## From Nautilus: “The Impossible Mathematics of the Real World”

Nautilus

June 8, 2017
Evelyn Lamb

Using stiff paper and transparent tape, Craig Kaplan assembles a beautiful roundish shape that looks like a Buckminster Fuller creation or a fancy new kind of soccer ball. It consists of four regular dodecagons (12-sided polygons with all angles and sides the same) and 12 decagons (10-sided), with 28 little gaps in the shape of equilateral triangles. There’s just one problem. This figure should be impossible. That set of polygons won’t meet at the vertices. The shape can’t close up.

Kaplan’s model works only because of the wiggle room you get when you assemble it with paper. The sides can warp a little bit, almost imperceptibly. “The fudge factor that arises just from working in the real world with paper means that things that ought to be impossible actually aren’t,” says Kaplan, a computer scientist at the University of Waterloo in Canada.

Impossibly real: This shape, which mathematician Craig Kaplan built using paper polygons, is only able to close because of subtle warping of the paper. Craig Kaplan

It is a new example of an unexpected class of mathematical objects that the American mathematician Norman Johnson stumbled upon in the 1960s. Johnson was working to complete a project started over 2,000 years earlier by Plato: to catalog geometric perfection. Among the infinite variety of three-dimensional shapes, just five can be constructed out of identical regular polygons: the tetrahedron, cube, octahedron, dodecahedron, and icosahedron. If you mix and match polygons, you can form another 13 shapes from regular polygons that meet the same way at every vertex—the Archimedean solids—as well as prisms (two identical polygons connected by squares) and “anti-prisms” (two identical polygons connected by equilateral triangles).

In 1966 Johnson, then at Michigan State University, found another 92 solids composed only of regular polygons, now called the Johnson solids. And with that, he exhausted all the possibilities, as the Russian mathematician Viktor Zalgaller, then at Leningrad State University, proved a few years later. It is impossible to form any other closed shapes out of regular polygons.

Yet in completing the inventory of polyhedra, Johnson noticed something odd. He discovered his shapes by building models from cardboard and rubber bands. Because there are relatively few possible polyhedra, he expected that any new ones would quickly reveal themselves. Once he started to put the sides into place, the shape should click together as a matter of necessity. But that didn’t happen. “It wasn’t always obvious, when you assembled a bunch of polygons, that what was assembled was a legitimate figure,” Johnson recalls.

A model could appear to fit together, but “if you did some calculations, you could see that it didn’t quite stand up,” he says. On closer inspection, what had seemed like a square wasn’t quite a square, or one of the faces didn’t quite lie flat. If you trimmed the faces, they would fit together exactly, but then they’d no longer be exactly regular.

Intent on enumerating the perfect solids, Johnson didn’t give these near misses much attention. “I sort of set them aside and concentrated on the ones that were valid,” he says. But not only does this niggling near-perfection draw the interest of Kaplan and other math enthusiasts today, it is part of a large class of near-miss mathematics.

There’s no precise definition of a near miss. There can’t be. A hard and fast rule doesn’t make sense in the wobbly real world. For now, Kaplan relies on a rule of thumb when looking for new near-miss Johnson solids: “the real, mathematical error inherent in the solid is comparable to the practical error that comes from working with real-world materials and your imperfect hands.” In other words, if you succeed in building an impossible polyhedron—if it’s so close to being possible that you can fudge it—then that polyhedron is a near miss. In other parts of mathematics, a near miss is something that is close enough to surprise or fool you, a mathematical joke or prank.

Some mathematical near misses are, like near-miss Johnson solids, little more than curiosities, while others have deeper significance for mathematics and physics.

he ancient problems of squaring the circle and doubling the cube both fall under the umbrella of near misses. They look tantalizingly open to solution, but ultimately prove impossible, like a geometric figure that seems as though it must close, but can’t. Some of the compass-and-straight-edge constructions by Leonardo da Vinci and Albrecht Dürer fudged the angles, producing nearly regular pentagons rather than the real thing.

Shell game: When the top shape is cut up into four pieces and rearranged, a gap appears, due to warping. Wikipedia

Then there’s the missing-square puzzle. In this one (above), a right triangle is cut up into four pieces. When the pieces are rearranged, a gap appears. Where’d it come from? It’s a near miss. Neither “triangle” is really a triangle. The hypotenuse is not a straight line, but has a little bend where the slope changes from 0.4 in the blue triangle to 0.375 in the red triangle. The defect is almost imperceptible, which is why the illusion is so striking.

A numerical coincidence is perhaps the most useful near miss in daily life: 27/12 is almost equal to 3/2. This near miss is the reason pianos have 12 keys in an octave and the basis for the equal-temperament system in Western music. It strikes a compromise between the two most important musical intervals: an octave (a frequency ratio of 2:1) and a fifth (a ratio of 3:2). It is numerically impossible to subdivide an octave in a way that ensures all the fifths will be perfect. But you can get very close by dividing the octave into 12 equal half-steps, seven of which give you a frequency ratio of 1.498. That’s good enough for most people.

Sometimes near misses arise within the realm of mathematics, almost as if mathematics is playing a trick on itself. In the episode “Treehouse of Horror VI” of The Simpsons, mathematically inclined viewers may have noticed something surprising: the equation 178212 + 184112 = 192212. It seemed for a moment that the screenwriters had disproved Fermat’s Last Theorem, which states that an equation of the form xn + yn = zn has no integer solution when n is larger than 2. If you punch those numbers into a pocket calculator, the equation seems valid. But if you do the calculation with more precision than most hand calculators can manage, you will find that the twelfth root of the left side of the equation is 1921.999999955867 …, not 1922, and Fermat can rest in peace. It is a striking near miss—off by less than a 10-millionth.

But near misses are more than just jokes. “The ones that are the most compelling to me are the ones where they’re potentially a clue that there’s a big story,” says University of California-Riverside mathematician John Baez. That’s the case for a number sometimes called the Ramanujan constant. This number is eπ √163, which equals approximately 262,537,412,640,768,743.99999999999925—amazingly close to a whole number. A priori, there’s no reason we should expect that these three irrational numbers—e, π, and √163—should somehow combine to form a rational number, let alone a perfect integer. There’s a reason they get so close. “It’s not some coincidence we have no understanding of,” says mathematician John Baez of the University of California, Riverside. “It’s a clue to a deep piece of mathematics.” The precise explanation is complicated, but hinges on the fact that 163 is what is called a Heegner number. Exponentials related to these numbers are nearly integers.

Or take the mathematical relationship fancifully known as “Monstrous Moonshine.” The story goes that in 1978 mathematician John McKay made an observation both completely trivial and oddly specific: 196,884 = 196,883 + 1. The first number, 196,884, had come up as a coefficient in an important polynomial called the j-invariant, and 196,883 came up in relation to an enormous mathematical object called the Monster group. Many people probably would have shrugged and moved along, but the observations intrigued some mathematicians, who decided to take a closer look. They uncovered connections between two seemingly unrelated subjects: number theory and the symmetries of the Monster group. These linkages may even have broader, as yet ungrasped, significance for other subjects. The physicist Edward Witten has argued that the Monster group may be related to quantum gravity and the deep structure of spacetime.

Mathematical near misses show the power and playfulness of the human touch in mathematics. Johnson, Kaplan, and others made their discoveries by trial and error—by exploring, like biologists trudging through the rainforest to look for new species. But with mathematics it can be easier to search systematically. For instance, Jim McNeill, a mathematical hobbyist who collects near misses on his website, and Robert Webb, a computer programmer, have developed software for creating and studying polyhedra.

Near misses live in the murky boundary between idealistic, unyielding mathematics and our indulgent, practical senses. They invert the logic of approximation. Normally the real world is an imperfect shadow of the Platonic realm. The perfection of the underlying mathematics is lost under realizable conditions. But with near misses, the real world is the perfect shadow of an imperfect realm. An approximation is “a not-right estimate of a right answer,” Kaplan says, whereas “a near-miss is an exact representation of an almost-right answer.”

In this way, near misses transform the mathematician’s and mathematical physicist’s relationship with the natural world. “I am grateful for the imperfections of the real world because it allows me to achieve a kind of quasi-perfection with objects that I know are intrinsically not perfect,” Kaplan says. “It allows me to overcome the limitations of mathematics because of the beautiful brokenness of reality.”

Stem Education Coalition

Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

## From Nautilus: “Unleashing the Power of Synthetic Proteins”

Nautilus

March 2017
David Baker, Baker Lab, U Washngton, BOINC Rosetta@home project

Dr. David Baker

Rosetta@home project

The opportunities for the design of synthetic proteins are endless.

Proteins are the workhorses of all living creatures, fulfilling the instructions of DNA. They occur in a wide variety of complex structures and carry out all the important functions in our body and in all living organisms—digesting food, building tissue, transporting oxygen through the bloodstream, dividing cells, firing neurons, and powering muscles. Remarkably, this versatility comes from different combinations, or sequences, of just 20 amino acid molecules. How these linear sequences fold up into complex structures is just now beginning to be well understood (see box).

Even more remarkably, nature seems to have made use of only a tiny fraction of the potential protein structures available—and there are many. Therein lies an amazing set of opportunities to design novel proteins with unique structures: synthetic proteins that do not occur in nature, but are made from the same set of naturally-occurring amino acids. These synthetic proteins can be “manufactured” by harnessing the genetic machinery of living things, such as in bacteria given appropriate DNA that specify the desired amino acid sequence. The ability to create and explore such synthetic proteins with atomic level accuracy—which we have demonstrated—has the potential to unlock new areas of basic research and to create practical applications in a wide range of fields.

The design process starts by envisioning a novel structure to solve a particular problem or accomplish a specific function, and then works backwards to identify possible amino acid sequences that can fold up to this structure. The Rosetta protein modelling and design software identifies the most likely candidates—those that fold to the lowest energy state for the desired structure. Those sequences then move from the computer to the lab, where the synthetic protein is created and tested—preferably in partnership with other research teams that bring domain expertise for the type of protein being created.

At present no other advanced technology can beat the remarkable precision with which proteins carry out their unique and beautiful functions. The methods of protein design expand the reach of protein technology, because the possibilities to create new synthetic proteins are essentially unlimited. We illustrate that claim with some of the new proteins we have already developed using this design process, and with examples of the fundamental research challenges and areas of practical application that they exemplify:

This image shows a designed synthetic protein of a type known as a TIM-barrel. Naturally occurring TIM-barrel proteins are found in a majority of enzymes, the catalysts that facilitate biochemical reactions in our bodies, in part because the circular cup-like or barrel shape at their core provides an appropriate space for the reaction to occur. The synthetic protein shown here has an idealized TIM-barrel template or blueprint that can be customized with pockets and binding sites and catalytic agents specific to particular reactants; the eight helical arms of the protein enhance the reaction space. This process can be used to design whole new classes of enzymes that do not occur in nature. Illustration and protein design prepared by Possu Huang in David Baker’s laboratory, University of Washington.

Catalysts for clean energy and medicine. Protein enzymes are the most efficient catalysts known, far more so than any synthesized by inorganic chemists. Part of that efficiency comes from their ability to accurately position key parts of the enzyme in relation to reacting molecules, providing an environment that accelerates a reaction or lowers the energy needed for it to occur. Exactly how this occurs remains a fundamental problem which more experience with synthetic proteins may help to resolve.

Already we have produced synthetic enzymes that catalyze potentially useful new metabolic pathways. These include: reactions that take carbon dioxide from the atmosphere and convert it into organic molecules, such as fuels, more efficiently than any inorganic catalyst, potentially enabling a carbon-neutral source of fuels; and reactions that address unsolved medical problems, including a potential oral therapeutic drug for patients with celiac disease that breaks down gluten in the stomach and other synthetic proteins to neutralize toxic amyloids found in Alzheimer’s disease.

We have also begun to understand how to design, de novo, scaffolds that are the basis for entire superfamilies of known enzymes (Fig. 1) and other proteins known to bind the smaller molecules involved in basic biochemistry. This has opened the door for potential methods to degrade pollutants or toxins that threaten food safety.

New super-strong materials. A potentially very useful new class of materials is that formed by hybrids of organic and inorganic matter. One naturally occurring example is abalone shell, which is made up of a combination of calcium carbonate bonded with proteins that results in a uniquely tough material. Apparently, other proteins involved in the process of forming the shell change the way in which the inorganic material precipitates onto the binding protein and also help organize the overall structure of the material. Synthetic proteins could potentially duplicate this process and expand this class of materials. Another class of materials are analogous to spider silk—organic materials that are both very strong and yet biodegradable—for which synthetic proteins might be uniquely suited, although how these are formed is not yet understood. We have also made synthetic proteins that create an interlocking pattern to form a surface only one molecule thick, which suggest possibilities for new anti-corrosion films or novel organic solar cells.

Targeted therapeutic delivery. Self-assembling protein materials make a wide variety of containers or external barriers for living things, from protein shells for viruses to the exterior wall of virtually all living cells. We have developed a way to design and build similar containers: very small cage-like structures—protein nanoparticles—that self-assemble from one or two synthetic protein building blocks (Fig. 2). We do this extremely precisely, with control at the atomic level. Current work focuses on building these protein nanoparticles to carry a desired cargo—a drug or other therapeutic—inside the cage, while also incorporating other proteins of interest on their surface. The surface protein is chosen to bind to a similar protein on target cells.

These self-assembling particles are a completely new way of delivering drugs to cells in a targeted fashion, avoiding harmful effects elsewhere in the body. Other nanoparticles might be designed to penetrate the blood-brain barrier, in order to deliver drugs or other therapies for brain diseases. We have also generated methods to design proteins that disrupt protein-protein interactions and proteins that bind to small molecules for use in biosensing applications, such as identifying pathogens. More fundamentally, synthetic proteins may well provide the tools that enable improved targeting of drugs and other therapies, as well as an improved ability to bond therapeutic packages tightly to a target cell wall.

A tiny 20-sided protein nanoparticle that can deliver drugs or other therapies to specific cells in the body with minimal side effects. The nanoparticle self-assembles from two types of synthetic proteins. Illustration and protein design prepared by Jacob Bale in David Baker’s laboratory, University of Washington.

Novel vaccines for viral diseases. In addition to drug delivery, self-assembling protein nanoparticles are a promising foundation for the design of vaccines. By displaying stabilized versions of viral proteins on the surfaces of designed nanoparticles, we hope to elicit strong and specific immune responses in cells to neutralize viruses like HIV and influenza. We are currently investigating the potential of these nanoparticles as vaccines against a number of viruses. The thermal stability of these designer vaccines should help eliminate the need for complicated cold chain storage systems, broadening global access to life saving vaccines and supporting goals for eradication of viral diseases. The ability to shape these designed vaccines with atomic level accuracy also enables a systematic study of how immune systems recognize and defend against pathogens. In turn, the findings will support development of tolerizing vaccines, which could train the immune system to stop attacking host tissues in autoimmune disease or over-reacting to allergens in asthma.

New peptide medicines. Most approved drugs are either bulky proteins or small molecules. Naturally occurring peptides (amino acid compounds) that are constrained or stabilized so that they precisely complement their biological target are intermediate in size, and are among the most potent pharmacological compounds known. In effect, they have the advantages of both proteins and small molecule drugs. The antibiotic cyclosporine is a familiar example. Unfortunately such peptides are few in number.

We have recently demonstrated a new computational design method that can generate two broad classes of peptides that have exceptional stability against heat or chemical degradation. These include peptides that can be genetically encoded (and can be produced by bacteria) as well as some that include amino acids that do not occur in nature. Such peptides are, in effect, scaffolds or design templates for creating whole new classes of peptide medicines.

In addition, we have developed general methods for designing small and stable proteins that bind strongly to pathogenic proteins. One such designed protein binds the viral glycoprotein hemagglutinin, which is responsible for influenza entry into cells. These designed proteins protect infected mice in both a prophylactic and therapeutic manner and therefore are potentially very powerful anti-flu medicines. Similar methods are being applied to design therapeutic proteins against the Ebola virus and other targets that are relevant in cancer or autoimmune diseases. More fundamentally, synthetic proteins may be useful as test probes in working out the detailed molecular chemistry of the immune system.

Protein logic systems. The brain is a very energy-efficient logic system based entirely on proteins. Might it be possible to build a logic system—a computer—from synthetic proteins that would self-assemble and be both cheaper and more efficient than silicon logic systems? Naturally occurring protein switches are well studied, but building synthetic switches remains an unsolved challenge. Quite apart from bio-technology applications, understanding protein logic systems may have more fundamental results, such as clarifying how our brains make decisions or initiate processes.

The opportunities for the design of synthetic proteins are endless, with new research frontiers and a huge variety of practical applications to be explored. In effect, we have an emerging ability to design new molecules to solve specific problems—just as modern technology does outside the realm of biology. This could not be a more exciting time for protein design.

Predicting Protein Structure

If we were unable to predict the structure that results from a given sequence of amino acids, synthetic protein design would be an almost impossible task. There are 20 naturally-occurring amino acids, which can be linked in any order and can fold into an astronomical number of potential structures. Fortunately the structure prediction problem is now well on the way toward being solved by the Rosetta protein modeling software.

The Rosetta tool evaluates possible structures, calculates their energy states, and identifies the lowest energy structure—usually, the one that occurs in a living organism. For smaller proteins, Rosetta predictions are already reasonably accurate. The power and accuracy of the Rosetta algorithms are steadily improving thanks to the work of a cooperative global network of several hundred protein scientists. New discoveries—such as identifying amino acid pairs that co-evolve in living systems and thus are likely to be co-located in protein structures—are also helping to improve prediction accuracy.

Our research team has already revealed the structures for more than a thousand protein families, and we expect to be able to predict the structure for nearly any protein within a few years. This is an important achievement with direct significance for basic biology and biomedical science, since understanding structure leads to understanding the function of the myriad proteins found in the human body and in all living things. Moreover, predicting protein structure is also the critical enabling tool for designing novel, “synthetic” proteins that do not occur in nature.

How to Create Synthetic Proteins that Solve Important Problems

A graduate student in the Baker lab and a researcher at the Institute for Protein Design discuss a bacterial culture (in the Petri dish) that is producing synthetic proteins. Source: Laboratory of David Baker, University of Washington.

Now that it is possible to design a variety of new proteins from scratch, it is imperative to identify the most pressing problems that need to be solved, and focus on designing the types of proteins that are needed to address these problems. Protein design researchers need to collaborate with experts in a wide variety of fields to take our work from initial protein design to the next stages of development. As the examples above suggest, those partners should include experts in industrial scale catalysis, fundamental materials science and materials processing, biomedical therapeutics and diagnostics, immunology and vaccine design, and both neural systems and computer logic. The partnerships should be sustained over multiple years in order to prioritize the most important problems and test successive potential solutions.

A funding level of \$100M over five years would propel protein design to the forefront of biomedical research, supporting multiple and parallel collaborations with experts worldwide to arrive at breakthroughs in medicine, energy, and technology, while also furthering a basic understanding of biological processes. Current funding is unable to meet the demands of this rapidly growing field and does not allow for the design and production of new proteins at an appropriate scale for testing and ultimately production, distribution, and implementation. Private philanthropy could overcome this deficit and allow us to jump ahead to the next generation of proteins—and thus to use the full capacity of the amino acid legacy that evolution has provided us.

My BOINC

Stem Education Coalition

Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

## From Nautilus: “Opening a New Window into the Universe”

Nautilus

April 2017
Andrea Ghez, UCLA, UCO

Andrea Ghez. PBS NOVA

The UCO Lick C. Donald Shane telescope is a 120-inch (3.0-meter) reflecting telescope located at the Lick Observatory, Mt Hamilton, in San Jose, California

Keck Observatory, Mauna Kea, Hawaii, USA

New technology could bring new insights into the nature of black holes, dark matter, and extrasolar planets.

Earthbound telescopes see stars and other astronomical objects through a haze. The light waves they gather have traveled unimpeded through space for billions of years, only to be distorted in the last millisecond by the Earth’s turbulent atmosphere. That distortion is now even more important, because scientists are preparing to build the three largest telescopes on Earth, each with light-gathering surfaces of 20 to 40 meters across.

The new giant telescopes:

ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile

TMT-Thirty Meter Telescope, proposed for Mauna Kea, Hawaii, USA

Giant Magellan Telescope, to be at Las Campanas Observatory, to be built some 115 km (71 mi) north-northeast of La Serena, Chile

In principle, the larger the telescope, the higher the resolution of astronomical images. In practice, the distorting veil of the atmosphere has always limited what can be achieved. Now, a rapidly evolving technology known as adaptive optics can strip away the veil and enable astronomers to take full advantage of current and future large telescopes. Indeed, adaptive optics is already making possible important discoveries and observations, including: the discovery of the supermassive black hole at the center of our galaxy, proving that such exotic objects exist; the first images and spectra of planetary systems around other stars; and high-resolution observations of galaxies forming in the early universe.

But adaptive optics has still not delivered its full scientific potential.

ESO 4LGSF Adaptive Optics Facility (AOF)

Existing technology can only partially correct the atmospheric blurring and cannot provide any correction for large portions of the sky or for the majority of the objects astronomers want to study.

The project we propose here to fully exploit the potential of adaptive optics by taking the technology to the next level would boost research on a number of critical astrophysical questions, including:

What are supermassive black holes and how do they work? Adaptive Optics has opened a new approach to studying supermassive black holes—through stellar orbits—but only the brightest stars, the tip of the iceberg, have been measured. With next generation adaptive optics we will be able to take the next leap forward in our studies of these poorly understood objects that are believed to play a central role in our universe. The space near the massive black hole at the center of our galaxy, for example, is a place where gravitational forces reach extreme levels. Does Einstein’s general theory of relativity still apply, or do exotic new physical phenomena emerge? How do these massive black holes shape their host galaxies? Early adaptive optics observations at the galactic center have revealed a completely unexpected environment, challenging our notions on the relationship between black holes and galaxies, which are a fundamental ingredient to cosmological models. One way to answer both of these questions is to find and measure the orbits of faint stars that are closer to the black hole than any known so far—which advanced adaptive optics would make possible.
The first direct images of an extrasolar planet—obtained with adaptive optics—has raised fundamental questions about star and planet formation. How exactly do new stars form and then spawn planets from the gaseous disks around them? New, higher resolution images of this process—with undistorted data from larger telescopes—can help answer this question, and may also reveal how our solar system was formed. In addition, although only a handful of new-born planets has been found to date, advanced adaptive optics will enable astronomers to find many more and help determine their composition and life-bearing potential.
Dark matter and dark energy are still completely mysterious, even though they constitute most of the universe.

Dark Energy Camera [DECam], built at FNAL

NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam

But detailed observations using adaptive optics of how light from distant galaxies is refracted around a closer galaxy to form multiple images—so-called gravitational lensing—can help scientists understand how dark matter and dark energy change space itself.

In addition, it is clear that telescopes endowed with advanced adaptive optics technology will inspire a whole generation of astronomers to design and carry out a multitude of innovative research projects that were previously not possible.

The laser system used to make artificial guide stars that sense the blurring effects of the Earth’s atmosphere being used on both Keck I and Keck II during adaptive optics observations of the center of our Galaxy. Next Generation Adaptive Optics would have multiple laser beams for each telescope. Ethan Tweedie

Sag A* NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way

The technology of adaptive optics is quite simple, in principle. First, astronomers measure the instantaneous turbulence in the atmosphere by looking at the light from a bright, known object—a “guide star”—or by using a laser tuned to make sodium atoms in a thin layer of the upper atmosphere fluoresce and glow as an artificial guide star.

ESO VLT Adaptive Optics new Guide Star laser light

The turbulence measurements are used to compute (also instantaneously) the distortions that turbulence creates in the incoming light waves. Those distortions are then counteracted by rapidly morphing the surface of a deformable mirror in the telescope. Measurements and corrections are done hundreds of times per second—which is only possible with powerful computing capability, sophisticated opto-mechanical linkages, and a real-time control system. We know how to build these tools.

Of course, telescopes that operate above the atmosphere, such as the Hubble Space Telescope, don’t need adaptive optics.

NASA/ESA Hubble Telescope

But both the Hubble and the coming next generation of space telescopes are small compared to the enormous earth-based telescopes now being planned.

LSST Camera, built at SLAC

LSST telescope, currently under construction at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

And for the kinds of research that require very high resolution, such as the topics mentioned above and many others, there is really no substitute for the light-gathering power of telescopes too huge to be put into space.

The next generation of adaptive optics could effectively take even the largest earth-bound telescopes “above the atmosphere” and make them truly amazing new windows on the universe. We know how to create this capability—the technology is in hand and the teams are assembled. It is time to put advanced adaptive optics to work.

Adaptive optics (AO) imaging technology is used to improve the performance of optical systems by correcting distortions on light waves that have traveled through a turbulent medium. The technology has revolutionized fields from ophthalmology and vision science to laser communications. In astronomy, AO uses sophisticated, deformable mirrors controlled by fast computers to correct, in real-time, the distortion caused by the turbulence of the Earth’s atmosphere. Telescopes equipped with AO are already producing sharper, clearer views of distant astronomical objects than had ever before been possible, even from space. But current AO systems only partially correct for the effects of atmospheric blurring, and only when telescopes are pointed in certain directions. The aim of Next Generation Adaptive Optics is to overcome these limitations and provide precise correction for atmospheric blurring anywhere in the sky.

One current limitation is the laser guide star that energizes sodium atoms in the upper atmosphere and causes them to glow as an artificial star used to measure the atmospheric distortions. This guide “star” is relatively close, only about 90 kilometers above the Earth’s surface, so the technique only probes a conical volume of the atmosphere above the telescope, and not the full cylinder of air through which genuine star light must pass to reach the telescope. Consequently, much of the distorting atmospheric structure is not measured. The next generation AO we propose will employ seven laser guide stars, providing full coverage of the entire cylindrical path travelled by light from the astronomical object being studied.

The next generation of adaptive optics will have several laser-created artificial guide stars, better optics, higher performance computers, and more advanced science instruments. Such a system will deliver the highest-definition images and spectra over nearly the entire sky and will enable unique new means of measuring the properties of stars, planets, galaxies, and black holes.
J.Lu (U of Hawaii) & T. Do (UCLA)

This technique can map the 3-D structure of the atmosphere, similar to how MRI medical imaging maps the human body. Simulations demonstrate that the resulting corrections will be excellent and stable, yielding revolutionary improvements in imaging. For example, the light from a star will be concentrated into a tiny area of the focal plane camera, and be far less spread out than it is with current systems, giving sharp, crisp images that show the finest detail possible.

This will be particularly important for existing large telescopes such as the W. M. Keck Observatory (WMKO) [above]—currently the world’s leading AO platform in astronomy. Both our team—the UCLA Galactic Center Group (GCG)—and the WMKO staff have been deeply involved in the development of next generation AO systems.

The quantum leap in the quality of both imaging and spectroscopy that next generation AO can bring to the Keck telescopes will likely pave the way for advanced AO systems on telescopes around the globe. For the next generation of extremely large telescopes, however, these AO advances will be critical. This is because the cylindrical volume of atmosphere through which light must pass to reach the mirrors in such large telescopes is so broad that present AO techniques will not be able to provide satisfactory corrections. For that reason, next generation AO techniques are critical to the future of infrared astronomy, and eventually of optical astronomy as well.

The total proposed budget is \$80 million over five years. The three major components necessary to take the leap in science capability include the laser guide star system, the adaptive optics system, and a powerful new science instrument, consisting of an infrared imager and an infrared spectrograph, that provides the observing capability to take advantage of the new adaptive optics system. This investment in adaptive optics will also help develop a strong workforce for other critical science and technology industries, as many students are actively recruited into industry positions in laser communications, bio-medical optics, big-data analytics for finance and business, image sensing and optics for government and defense applications, and the space industry. This investment will also help keep the U.S. in the scientific and technological lead. Well-funded European groups have recognized the power of AO and are developing competitive systems, though the next generation AO project described here will set an altogether new standard.

Federal funding agencies find the science case for this work compelling, but they have made clear that it is beyond present budgetary means. Therefore, this is an extraordinary opportunity for private philanthropy—for visionaries outside the government to help bring this ambitious breakthrough project to reality and open a new window into the universe.

Andrea Ghez is the Lauren B. Leichtman & Arthur E. Levine Chair in Astrophysics Director, UCLA Galactic Center Group.

Stem Education Coalition

Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

## From Nautilus: “The Origin of the Universe”

Nautilus

April 2017
John Carlstrom

The current South Pole telescope measuring small variations in the cosmic microwave background radiation that permeates the universe. Multiple telescopes with upgraded detectors could unlock additional secrets about the origins of the universe. Jason Gallicchio

Measuring tiny variations in the cosmic microwave background will enable major discoveries about the origin of the universe.

CMB per ESA/Planck

ESA/Planck

How is it possible to know in detail about things that happened nearly 14 billion years ago? The answer, remarkably, could come from new measurements of the cosmic microwave radiation that today permeates all space, but which was emitted shortly after the universe was formed.

Previous measurements of the microwave background showed that the early universe was remarkably uniform, but not perfectly so: There are small variations in the intensity (or temperature) and polarization of the background radiation. These faint patterns show close agreement with predictions from what is now the standard theoretical model of how the universe began. That model describes an extremely energetic event—the Big Bang—followed within a tiny fraction of a second by a period of very accelerated expansion of the universe called cosmic inflation.

Alan Guth, Highland Park High School, NJ, USA and M.I.T., who first proposed cosmic inflation

HPHS Owls

Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex MittelmannColdcreation

Alan Guth’s notes. http://www.bestchinanews.com/Explore/4730.html

During this expansion, small quantum fluctuations were stretched to astrophysical scales, becoming the seeds that gave rise to the galaxies and other large-scale structures of the universe visible today.

Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

After the cosmic inflation ended, the expansion began to slow and the primordial plasma of radiation and high-energy sub-atomic particles began to cool. Within a few hundred thousand years, the plasma had cooled sufficiently for atoms to form, for the universe to become transparent to light, and for the first light to be released. That first light has since been shifted—its wavelengths stretched 1,000-fold into the microwave spectrum by the continuing expansion of the universe—and is what we now measure as the microwave background [see above].

Inflationary Universe. NASA/WMAP

Recently the development of new superconducting detectors and more powerful telescopes are providing the tools to conduct an even more detailed study of the microwave background. And the payoff could be immense, including additional confirmation that cosmic inflation actually occurred, when it occurred, and how energetic it was, in addition to providing new insights into the quantum nature of gravity. Specifically the new research we propose can address a wide range of fundamental questions:

1. The accelerated expansion of the universe in the first fraction of a second of its existence, as described by the inflation model, would have created a sea of gravitational waves. These distortions in spacetime would in turn would have left a distinct pattern in the polarization of the microwave background. Detecting that pattern would thus provide a key test of the inflation model, because the level of the polarization links directly to the time of inflation and its energy scale.
2. Investigating the cosmic gravitational wave background would build on the stunning recent discovery of gravity waves, apparently from colliding black holes, helping to further the new field of gravitational wave astronomy.
3. These investigations would provide a valuable window on physics at unimaginably high energy scales, a trillion times more energetic than the reach of the most powerful Earth-based accelerators.
4. The cosmic microwave background provides a backlight on all structure in the universe. Its precise measurement will illuminate the evolution of the universe to the present day, allowing unprecedented insights and constraints on its still mysterious contents and the laws that govern them.

The origin of the universe was a fantastic event. To gain an understanding of that beginning as an inconceivably small speck of spacetime and its subsequent evolution is central to unraveling continuing mysteries such as dark matter and dark energy. It can shed light on how the two great theories of general relativity and quantum mechanics relate to each other. And it can help us gain a clearer perspective on our human place within the universe. That is the opportunity that a new generation of telescopes and detectors can unlock.

How to Measure Variations in the Microwave Background with Unparalleled Precision

Figure 1Ultra-sensitive superconducting bolometer detectors manufactured with thin-film techniques. The project proposes to deploy 500,000 such detectors. Chrystian Posada Arbelaez.

The time for the next generation cosmic microwave background experiment is now. Transformational improvements have been made in both the sensitivity of microwave detectors and the ability to manufacture them in large numbers at low cost. The advance stems from the development of ultra-sensitive superconducting detectors called bolometers. These devices (Figure 1) essentially eliminate thermal noise by operating at a temperature close to absolute zero, but also are designed to make sophisticated use of electrothermal feedback—adjusting the current to the detectors when incoming radiation deposits energy, so as to keep the detector at its critical superconducting transition temperature under all operating conditions. The sensitivity of these detectors is limited only by the noise of the incoming signal—they generate an insignificant amount of noise of their own.

Equally important are the production advances. These new ultra-sensitive detectors are manufactured with thin film techniques adapted from Silicon Valley—although using exotic superconducting materials—so that they can be rapidly and uniformly produced at greatly reduced cost. That’s important, because the proposed project needs to deploy about 500,000 detectors in all—something that would not be possible with hand-assembled devices as in the past. Moreover, the manufacturing techniques allow these sophisticated detectors to automatically filter the incoming signals for the desired wavelength sensitivity.

Figure 2The current focal plane on the South Pole Telescope with seven wafers of detectors plus hand-assembled individual detectors. A single detector wafer of the advanced design proposed here would provide more sensitivity and frequency coverage than this entire focal plane; the project would deploy several hundred such wafers across 10 or more telescopes. Jason Henning.

To deploy the detectors, new telescopes are needed that have a wide enough focal plane to accommodate a large number of detectors—about 10,000 per telescope to capture enough incoming photons and see a wide enough area of the sky (Figure 2). They need to be placed at high altitude, exceedingly dry locations, so as to minimize the water vapor in the atmosphere that interferes with the incoming photons. The plan is to build on the two sites already established for ongoing background observations, the high Antarctic plateau at the geographic South Pole, and the high Atacama plateau in Chile. Discussions are underway with the Chinese about developing a site in Tibet; Greenland is also under consideration. In all, about 10 specialized telescopes will be needed, and will need to operate for roughly 5 years to accomplish the scientific goals described above. Equally important, the science teams that have come together to do this project will need significant upgrades to their fabrication and testing capabilities.

The resources needed to accomplish this project are estimated at \$100 million over 10 years, in addition to continuation of current federal funding. The technology is already proven and the upgrade path understood. Equally important, a cadre of young, enthusiastic, and well-trained scientists are eager to move forward. Unfortunately, constraints on the federal funding situation are already putting enormous stress on the ability of existing teams just to continue, and the expanded resources to accomplish the objectives described above are not available. This is thus an extraordinary opportunity for private philanthropy—an opportunity to “see” back in time to the very beginning of the universe and to understand the phenomena that shaped our world.

Stem Education Coalition

Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

## From Nautilus: “The Physicist Who Denies Dark Matter” Revised and Improved from post of 2017/03/01

Nautilus

May 18, 2017
Oded Carmeli

Mordehai Milgrom. Cosmos on Nautilus

Maybe Newtonian physics doesn’t need dark matter to work.

He is one of those dark matter people,” Mordehai Milgrom said about a colleague stopping by his office at the Weizmann Institute of Science. Milgrom introduced us, telling me that his friend is searching for evidence of dark matter in a project taking place just down the hall.

“There are no ‘dark matter people’ and ‘MOND people,’ ” his colleague retorted.

“I am ‘MOND people,’” Milgrom proudly proclaimed, referring to Modified Newtonian Dynamics, his theory that fixes Newtonian physics instead of postulating the existence of dark matter and dark energy—two things that, according to the standard model of cosmology, constitute 95.1 percent of the total mass-energy content of the universe.

This friendly incident is indicative of (“Moti”) Milgrom’s calmly quixotic character. There is something almost misleading about the 70-year-old physicist wearing shorts in the hot Israeli summer, whose soft voice breaks whenever he gets excited. Nothing about his pleasant demeanor reveals that this man claims to be the third person to correct Newtonian physics: First Max Planck (with quantum theory), then Einstein (with relativity), now Milgrom.

This year marks Milgrom’s 50th year at the Weizmann.

Weizmann Institute Campus

I visited him there to learn more about how it feels to be a science maverick, what he appreciates about Thomas Kuhn’s The Structure of Scientific Revolutions, and why he thinks dark matter and dark energy don’t exist.

NASA

What inspired you to dedicate your life to the motion of stars?

I remember very vividly the way physics struck me. I was 16 and I thought: Here is a way to understand how things work, far beyond the understanding of my peers. It wasn’t a long-term plan. It was a daily attraction. I simply loved physics, the same way other people love art or sports. I never dreamed of one day making a major discovery, like correcting Newton.

I had a terrific physics teacher at school, but when you study textbook material, you’re studying done deals. You still don’t see the effort that goes into making breakthrough science, when things are unclear and advances are made intuitively and often go wrong. They don’t teach you that at school. They teach you that science always goes forward: You have a body of knowledge, and then someone discovers something and expands that body of knowledge. But it doesn’t really work that way. The progress of science is never linear.

How did you get involved with the problem of dark matter?

Toward the end of my Ph.D., the physics department here wanted to expand. So they asked three top Ph.D. students working on particle physics to choose a new field. We chose astrophysics, and the Weizmann Institute pulled some strings with institutions abroad so they would accept us as postdocs. And so I went to Cornell to fill my gaps in astrophysics.

After a few years in high energy astrophysics, working on the physics of X-ray radiation in space, I decided to move to yet another field: The dynamics of galaxies. It was a few years after the first detailed measurements of the speed of stars orbiting spiral galaxies came in. And, well, there was a problem with the measurements.

To understand this problem, one needs to wrap one’s head around some celestial rotations. Our planet orbits the sun, which, in turn, orbits the center of the Milky Way galaxy. Inside solar systems, the gravitational pull from the mass of the sun and the speed of the planets are in balance. By Newton’s laws, this is why Mercury, the innermost planet in our solar system, orbits the sun at over 100,000 miles per hour, while the outermost plant, Neptune, is crawling at just over 10,000 miles per hour.

Milky Way NASA/JPL-Caltech /ESO R. Hurt

Now, you might assume that the same logic would apply to galaxies: The farther away the star is from the galaxy’s center, the slower it revolves around it; however, while at smaller radiuses the measurements were as predicted by Newtonian physics, farther stars proved to move much faster than predicted from the gravitational pull of the mass we see in these galaxies. The observed gap got a lot wider when, in the late 1970s, radio telescopes were able to detect and measure the cold gas clouds at the outskirts of galaxies. These clouds orbit the galactic center five times farther than the stars, and thus the anomaly grew to become a major scientific puzzle.

One way to solve this puzzle is to simply add more matter. If there is too little visible mass at the center of galaxies to account for the speed of stars and gas, perhaps there is more matter than meets the eye, matter that we cannot see, dark matter.

What made you first question the very existence of dark matter?

What struck me was some regularity in the anomaly. The rotational velocities were not just larger than expected, they became constant with radius. Why? Sure, if there was dark matter, the speed of stars would be greater, but the rotation curves, meaning the rotational speed drawn as a function of the radius, could still go up and down depending on its distribution. But they didn’t. That really struck me as odd. So, in 1980, I went on my Sabbatical in the Institute for Advance Studies in Princeton with the following hunch: If the rotational speeds are constant, then perhaps we’re looking at a new law of nature. If Newtonian physics can’t predict the fixed curves, perhaps we should fix Newton, instead of making up a whole new class of matter just to fit our measurements.

If you’re going to change the laws of nature that work so well in our own solar system, you need to find a property that differentiates solar systems from galaxies. So I made up a chart of different properties, such as size, mass, speed of rotation, etc. For each parameter, I put in the Earth, the solar system and some galaxies. For example, galaxies are bigger than solar systems, so perhaps Newton’s laws don’t work over large distances? But if this was the case, you would expect the rotation anomaly to grow bigger in bigger galaxies, while, in fact, it is not. So I crossed that one out and moved on to the next properties.

I finally struck gold with acceleration: The pace at which the velocity of objects changes.

NASA

We usually think of earthbound cars that accelerate in the same direction, but imagine a merry-go-round. You could be going in circles and still accelerate. Otherwise, you would simply fall off. The same goes for celestial merry-go-rounds. And it’s in acceleration that we find a big difference in scales, one that justifies modifying Newton: The normal acceleration for a star orbiting the center of a galaxy is about a hundred million times smaller than that of the Earth orbiting the sun.

For those small accelerations, MOND introduces a new constant of nature, called a0. If you studied physics in high school, you probably remember Newton’s second law: force equals mass times acceleration, or F=ma. While this is a perfectly good tool when dealing with accelerations much greater than a0, such as those of the planets around our sun, I suggested that at significantly lower accelerations, lower even than that of our sun around the galactic center, force becomes proportional to the square of the acceleration, or F=ma2/a0.

To put it in other words: According to Newton’s laws, the rotation speed of stars around galactic centers should decrease the farther the star is from the center of mass. If MOND is correct, it should reach a constant value, thus eliminating the need for dark matter.

I didn’t share these thoughts with my colleagues at Princeton. I was afraid to come across as, well, crazy. And then, in 1981, when I already had a clear idea of MOND, I didn’t want anyone to jump on my wagon, so to speak, which is even crazier when you think about it. Needless to say [laughs] no one jumped on my wagon, even when I desperately wanted them to.

Well, you were 35 and you proposed to fix Newton.

Why not? What’s the big deal? If something doesn’t work, fix it. I wasn’t trying to be bold. I was very naïve at the time. I didn’t understand that scientists are just as swayed as other people by conventions and interests.

Like Thomas Kuhn’s The Structure of Scientific Revolutions.

I love that book. I read it several times. It showed me how my life’s story has happened to so many others scientists throughout history. Sure, it’s easy to make fun of people who once objected to what we now know is good science, but are we any different? Kuhn stresses that these objectors are usually good scientists with good reasons to object. It is just that the dissenters usually have a unique point of view of things that is not shared by most others. I laugh about it now, because MOND has made such progress, but there were times when I felt depressed and isolated.

What’s it like being a science maverick?

By and large, the last 35 years have been exciting and rewarding exactly because I have been advocating a maverick paradigm. I am a loner by nature, and despite the daunting and doubting times, I much prefer this to being carried with the general flow. I was quite confident in the basic validity of MOND from the very start, which helped me a lot in taking all this in stride, but there are two great advantages to the lingering opposition to MOND: Firstly, it gave me time to make more contributions to MOND than I would had the community jumped on the MOND wagon early on. Secondly, once MOND is accepted, the long and wide resistance to it will only have proven how nontrivial an idea it is.

By the end of my sabbatical in Princeton, I had secretly written three papers introducing MOND to the world. Publishing them, however, was a whole different story. At first I sent my kernel paper to journals such as Nature and Astrophysical Journal Letters, and it got rejected almost off-hand. It took a long time until all three papers were published, side by side, in Astrophysical Journal.

The first person to hear about MOND was my wife Yvonne. Frankly, tears come to my eyes when I say this. Yvonne is not a scientist, but she has been my greatest supporter.

The first scientist to back MOND was another physics maverick: The late Professor Jacob Bekenstein, who was the first to suggest that black holes should have a well-defined entropy, later dubbed the Bekenstein-Hawking entropy. After I submitted the initial MOND trilogy, I sent the preprints to several astrophysicists, but Jacob was the first scientist I discussed MOND with. He was enthusiastic and encouraging from the very start.

Slowly but surely, this tiny opposition to dark matter grew from just two physicists to several hundred proponents, or at least scientists who take MOND seriously. Dark matter is still the scientific consensus, but MOND is now a formidable opponent that proclaims the emperor has no clothes, that dark matter is our generation’s ether.

So what happened? As far as dark matter is concerned, nothing really. A host of experiments searching for dark matter, including the Large Hadron Collider, many underground experiments and several space missions, have failed to directly observe its very existence. Meanwhile, MOND was able to accurately predict the rotation of more and more spiral galaxies—over 150 galaxies to date, to be precise.

All of them? Some papers claim that MOND wasn’t able to predict the dynamics of certain galaxies.

That’s true and it’s perfectly fine, because MOND’s predictions are based on measurements. Given the distribution of regular, visible matter alone, MOND can predict the dynamics of galaxies. But that prediction is based on our initial measurements. We measure the light coming in from a galaxy to calculate its mass, but we often don’t know the distance to that galaxy for sure, so we don’t know for certain just how massive that galaxy really is. And there are other variables, such as molecular gas, that we can’t observe at all. So yes, some galaxies don’t perfectly match MOND’s predictions, but all in all, it’s almost a miracle that we have enough data on galaxies to prove MOND right, over and over again.

Your opponents say MOND’s greatest flaw is its incompatibility with relativistic physics.

In 2004, Bekenstein proposed his TeVeS, or Relativistic Gravitational Theory for MOND.

Since then, several different relativistic MOND formulations have been put forth, including one by me, called Bimetric MOND, or BIMOND.

So, no, incorporating MOND into Einsteinian physics is no longer a challenge. I hear this statement still made, but only from people who parrot others, who themselves are not abreast with the developments of the last 10 years. There are several relativistic versions of MOND. What remains a challenge is demonstrating that MOND can account for the mass anomalies in cosmology.

Another argument that cosmologists often make is that dark matter is needed not just for motion within galaxies, but on even larger scales. What does MOND have to say about that?

According to the Big Bang theory, the universe began as a uniform singularity 13.8 billion years ago. And, just as in galaxies, observations made of the cosmic background radiation from the early universe suggest that the gravity of all the matter in the universe is simply not enough to form the different patterns we currently see, like galaxies and stars, in just 13.8 billion years. Once again, dark matter was called to the rescue: It does not emit radiation, but it does engage visible material with gravitation. And so, starting from the 1980s, the new cosmological dogma was that dark matter constituted a staggering 95 percent of all matter in the universe. That lasted, well, right until the bomb hit us in 1998.

It turned out that the expansion of the universe is accelerating, not decelerating like all of us originally thought.

Timeline of the universe, assuming a cosmological constant. Coldcreation/wikimedia, CC BY-SA

Any form of genuine matter, dark or not, should have slowed down acceleration. And so a whole new type of entity was invented: Dark energy. Now the accepted cosmology is that the universe is made up of 70 percent dark energy, 25 percent dark matter, and 5 percent regular matter..

Dark energy depiction. Image: Volker Springle/Max Planck Institute for Astrophysics/SP)

But dark energy is just a quick fix, the same as dark matter is. And just as in galaxies, you can either invent a whole new type of energy and then spend years trying to understand its properties, or you can try fixing your theory.

Among other things, MOND points to a very deep connection between structure and dynamics in galaxies and cosmology. This is not expected in accepted physics. Galaxies are tiny structures within the grand scale of the universe, and those structures can behave differently without contradicting the current cosmological consensus. However, MOND creates this connection, binding the two.

This connection is surprising: For whatever reason, the MOND constant of a0 is close to the acceleration that characterizes the universe itself. In fact, MOND’s constant equals the speed of light squared, divided by the radius of universe.

So, indeed, to your question, the conundrum pointed to is valid at present. MOND doesn’t have a sufficient cosmology yet, but we’re working on it. And once we fully understand MOND, I believe we’ll also fully understand the expansion of the universe, and vice versa: A new cosmological theory would explain MOND. Wouldn’t that be amazing?

What do you think about the proposed unified theories of physics, which merge MOND with quantum mechanics?

These all hark back to my 1999 paper on MOND as a vacuum effect, where it was pointed out that the quantum vacuum in a universe such as ours may produce MOND behavior within galaxies, with the cosmological constant appearing in the guise of the MOND acceleration constant, a0. But I am greatly gratified to see these propositions put forth, especially because they are made by people outside the traditional MOND community. It is very important that researchers from other backgrounds become interested in MOND and bring new ideas to further our understanding of its origin.

And what if you had a unified theory of physics that explains everything? What then?

You know, I’m not a religious person, but I often think about our tiny blue dot, and the painstaking work we physicists do here. Who knows? Perhaps somewhere out there, in one of those galaxies I spent my life researching, there already is a known unified theory of physics, with a variation of MOND built into it. But then I think: So what? We still had fun doing the math. We still had the thrill of trying to wrap our heads around the universe, even if the universe never noticed it at all.

Stem Education Coalition

Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

## From Nautilus: “Defy the Stars” spoiler alert, this is SciFi.

Nautilus

May 11, 2017
Claudia Gray

Count to five, Noemi decides. If she’s cracking up—if the terror of the past few minutes has scrambled her mind to the point where she’s hallucinating—then this will all go away in a couple of seconds. If this is for real, the mech will be standing here waiting for orders when she’s done.

One. The mech remains still, expression curious and patient.

Two. Noemi takes a deep breath. She remains in her crouch, hand clutching her blaster so tightly her fingers have begun to cramp.

Three. Abel. The mech said its name was Abel. We were taught that there are twenty-five models of mech in the Mansfield Cybernetics line, alphabetical from B to Z. A was for a prototype.

Four. Abel’s face and posture haven’t shifted in the slightest. Would it stand here for an hour? A whole day? At any rate, it hasn’t made any move to get its weapon back.

Five.

Noemi grabs Abel’s blaster. “My friend in the docking bay—she needs medical help, now.”

“Understood. I’ll bring her to sick bay.” Abel takes off down the hallway so quickly that Noemi first thinks it’s escaping—but it’s apparently following her orders, just like it said it would.

Shoving herself to her feet, Noemi runs after the mech, unwilling to let the thing out of her sight even though she knows she can’t possibly keep up.

No image caption or credit.

From Darius Akide’s lectures on mechs, Noemi knows the A model was an experimental model never put into mass production. Could the mech be lying about what it is? Its programming could potentially allow it to lie. But like everyone else on Genesis, she has memorized the faces of every single model of mech. According to her history books, they used to fear infiltration, in the early days of the Liberty War. What if the machines had walked among them, pretending to be human, spying on them all?

While the Queens and Charlies are most familiar to her, Noemi could identify any of Mansfield’s mechs on sight—and she’s never seen this Abel’s face before.

Okay, you found a prototype. It doesn’t matter how it got out here as long as you can use it. Take care of Esther and worry about the rest later.

Her footsteps pound a staccato drumbeat along the corridor as Noemi dashes back to the docking bay. Panting, she stops in the doorway to stare at the scene in front of her. Abel leans over Esther’s damaged fighter, gently scooping her into its arms. Esther’s head lolls back as she murmurs, “Who—who are—”

“It’s a mech,” Noemi calls as she ditches her nearly dead blaster, then holsters Abel’s to her side. “The ship has a fully equipped sick bay. See? We can take care of you.”

Abel moves slowly, deliberately, until Esther rests against its chest in a firm embrace. Then Noemi barely has time to get out of the way before it rushes out, moving at a speed no human could match.

When she gets all the way back up to sick bay, Esther’s lying on a biobed. Abel’s deft fingers move across the controls so swiftly they seem to blur. Noemi goes to Esther’s side and takes her hand.

“The sensors are still assessing her condition,” Abel reports. “But I predict they’ll confirm preliminary findings of internal bleeding, multiple pelvic fractures, and a mild-to-moderate concussion. If internal bleeding is confirmed, she’ll need an immediate transfusion. I’ve administered pain medication.”

Enough medication to leave Esther dazed, her eyes half closed and her facial muscles slack—Good, Noemi thinks. Esther needs that. And the nauseous weight in her gut lessens, because those injuries sound survivable. Fixable. At least, if this Abel mech actually knows what it’s doing. “How are you—” She has to stop and gulp in another few breaths before she can continue talking. “You’re one of the medical models? I thought—thought that was the Tare mech.”

“To the best of my knowledge, the Tare mech remains the primary medical model,” Abel says, as amiably as if they were having tea. The ozone-seared air still stinks of their battle only minutes before. “However, I am programmed with the knowledge, skills, and specialties of the entire Mansfield Cybernetics line.” It glances over from the readouts to study Noemi’s face for a moment. “You’re experiencing extreme shortness of breath. This shouldn’t represent an emergency unless you have any underlying medical conditions. Do you?”

“What? No.” It’s so strange, talking to a mech. Standing beside one. It feels just like standing next to a person, even though nothing could be further from the truth. “I just— pushed myself. That’s all.”

“You could’ve remained in sick bay instead of following me down,” it points out.

“I don’t trust you.”

“I wasn’t asking for a justification for your actions. Humans have many reasons for behaving in an inefficient or irrational manner.” Abel’s tone is so mild that it takes Noemi a moment to recognize the insult.

But that’s stupid. She’s anthropomorphizing a mech—a recruit’s mistake, one she should be past. Apparently this prototype’s innovations don’t include tact.

The dark, glistening stuff in the bags Abel brings out must be synthetic blood. He’s very sure about that transfusion. Some faiths on Genesis won’t use synthetic blood, others won’t accept transfusions at all, but Esther’s family doesn’t belong to one of those.

Noemi imagines the Gatsons standing before her, tall and pale, their expressions disapproving. How could you let this happen? they might say. You were supposed to protect our daughter. After everything we did for you, how could you let her be hurt?

Smoothly, the mech slips the needle into Esther’s skin. Not a flicker of discomfort shows on her face. Is she that doped up, or is the mech that good? Probably both, Noemi decides. While Abel works, she studies its—his face in greater depth. There really is something different about this one. He looks younger than most mechs, as if he’s perhaps two or three years older she is. Instead of the customary, blandly appealing mech features, he has a distinctive face with piercing blue eyes, a strong nose, and, if she recalls correctly, a slightly asymmetrical smile.

Why make a mech so … specific? And so advanced? Akide had told them that mechs were calibrated to the level of intelligence they required for their duties, nothing more. Extra intelligence would only be a complication, another way for a mech to break down. There were even laws against developing mech intelligence too far, or there had been, the last anyone on Genesis heard about Earth laws. If Abel is telling her the truth—and by now she believes he is—he represents a significant step forward in cybernetics development.

Except that he can’t be. This ship was abandoned many years ago. As she brushes a strand of hair away from Esther’s cheek, Noemi asks, “How long have you been aboard the Daedalus?”

“Not quite thirty years,” Abel says. “I can provide the exact time down to the nanosecond if required.”

“It isn’t.” It so, so isn’t.

“I doubted it would be.” Abel turns away from the medical readouts to face her directly. “Upon further examination, the patient’s liver appears to be ruptured, and the internal bleeding is more severe than initially indicated. Surgery will be required.”

Noemi’s abdomen knots in sympathetic pain. “But—if Esther loses her liver, she won’t survive.”

Abel walks away from the biobed, toward various storage chambers—even past a few cryosleep pods against the wall. “The Daedalus is stocked with artificial organs in case emergency transplants are needed.”

She bites her lower lip. Although Genesis has retained more medical technology than any other kind, artificial organs are used very rarely. Yes, life is precious and must be preserved, but death is accepted as a part of life. Unnaturally avoiding death is seen as an act of futility, sometimes even one of cowardice. The Gatsons are particularly strict about these things. They spent weeks debating whether or not Mr. Gatson should even have laser surgery on his eyes.

This is different. Esther’s only seventeen! She was injured trying to protect our world. Noemi didn’t sign up for the Masada Run only to have Esther die anyway. “All right,” she says. “All right. Do it.”

From the biobed comes a whisper: “Don’t.”

Noemi looks down to see Esther gazing up. Her skin, always fair, has turned waxen. One of her pale green eyes is horribly marred, deep red where it ought to be white. But she’s awake.

“It’s okay.” Noemi tries to smile. “I’m here. Do you need more pain meds?”

“It doesn’t hurt.” Esther sighs deeply. Her eyelids droop, but for only a moment. She’s fighting so hard to stay awake. “No transplant.”

It’s like the chill of space outside the ship’s hull rushed in to freeze Noemi’s blood. She feels adrift, exposed, vulnerable. Like she’s the one in mortal danger instead of Esther. “No, no, it’s all right. This is an emergency—”

“It would make me part machine. That isn’t human life. Not the life I was given.”

Please, God, no. God doesn’t speak to Noemi’s heart, no matter how often she prays for guidance. But maybe he’ll speak to Esther’s. Show her it’s more important to stay alive no matter what. The Gatsons raised them so strictly, and Esther’s always obeyed her parents. Now, though—who could argue with this?

“Esther, please.” Noemi’s voice has begun to shake. “If you don’t have the transplant, you’ll die.”

“I know.” Esther feebly moves her hand, searching for Noemi’s; Noemi takes it and hangs on tight. Esther’s skin is growing cold. “I knew as soon as the mech tore through my ship. Please—don’t argue while we’re saying good-bye—”

“To hell with good-bye!” Noemi will make this up to Esther later. “You. Abel. Perform the transplant.”

Abel, who’s been standing in the middle of sick bay through this entire conversation, shakes his head no. “I’m sorry, but I can’t.”

“You just said you had all the talents of every mech ever! Were you lying?”

“I don’t mean that I am incapable of performing the transplant.” If she didn’t know better, she’d think Abel was offended. “And I cannot lie to you, as my commander.”

“That’s right. I’m your commander.” Noemi seizes onto this, the one weapon she has that might make Abel stop arguing and move, dammit. “So you have to follow my orders, and I’m ordering you to perform the transplant.”

“Noemi—” Esther whispers. The weakness in her voice slices through Noemi like a blade, but she doesn’t let herself look away from the mech. Abel is Esther’s only hope.

He doesn’t take a single step closer as he says, “Your authority over me is subject to a few strictly limited exceptions. One of those exceptions is that I must obey the wishes of a medical patient regarding end-of-life decisions. Esther’s choice is therefore final.”

No image caption or credit.

Damn, damn, damn! The same programming that saved her life is endangering Esther’s. Why would Mansfield build legions of killing machines and then program them with mock morality? Just one more way the people of Earth fool themselves into accepting the machines in their midst, like the human skin and hair. Noemi wants to scream at Abel but knows it would do no good. Programming is final. Absolute.

Instead she bends closer to Esther, brushing her friend’s pale-gold hair away from her face. “If you won’t do it for yourself, then do it for me. We’re on this spaceship out in the middle of nowhere, and I need your help to—to—”

But it’s not help she needs. It’s Esther herself. Noemi knows she’s only made one real friend in her life, but she only ever needed one, because it was Esther, who knew every awful thing about her and loved her anyhow. Noemi’s bad temper and awkwardness and distrust—the same stuff that pushed Mr. and Mrs. Gatson and Jemuel and everybody else away—Esther was the only person who didn’t think those things mattered. The only one who ever would.

A sob bubbles up in Noemi’s throat, but she chokes it back to whisper, once again, “Please. You’re supposed to be the one who goes back. You’re the one who’s going to make it.” The one who can be happy. The one who can be good, who can love and be loved. Noemi can only be the one left over.

“You were willing to die for me,” Esther says. For one moment she’s really able to focus on Noemi; maybe the blood flowing into her is helping a little. “At least now you won’t have to. Not if you take your name off the list. You can now. Promise me you will.”

“Esther—”

“Tell Mom and Dad I love them.”

Abel chooses this moment to interrupt. “I had a thought.”

“Is it about getting around your idiotic programming?” Noemi snaps. Oh, why did she have to say it like that? She doesn’t want Esther to hear her being mean, not now.

“Cryosleep.” Abel points at the pods against the wall. “Often even severely injured people can be successfully put into cryosleep. If she weren’t brought out of it until an organ could be cloned, perhaps—”

Esther wouldn’t agree to cloning either, but cryosleep would be okay. What they’d do after that … Noemi doesn’t have to think of that now. She can leave it to the doctors once they’re back on Genesis. “Yes! Please, yes, put her in cryosleep!”

“I’ll check on the pods.” Abel’s on it in an instant, finally making himself useful again. But after a few moments, he pauses. “I’m afraid the cryosleep pods’ power source was damaged in the attack on the Daedalus thirty years ago.”

“Isn’t there any way around it?” On a ship this size, Noemi knows, every vital system should have backup.

“Normally the ship’s main grid would provide backup power, but I took that offline.”

“I thought you were supposed to be helping me!”

“I am now,” Abel says, his tone maddeningly even. “I wasn’t when you first boarded the ship. At that point you were considered an intruder and—”

“It doesn’t matter!” Noemi’s almost screaming by now, and she doesn’t care. “Just bring the main grid back up!”

Abel nods and rushes toward sick bay’s main computer interface. Noemi takes a deep breath to steady herself before she leans back down toward Esther. “It’s going to be all right,” she whispers. “We’ve got a plan now. …”

Esther’s eyes are closed. She doesn’t hear. Noemi looks up at the biobed and sees the dark truth the sensors reveal: Esther is dying. Right now. This moment.

“Esther?” Noemi touches her friend’s shoulder, stricken. “Can you hear me?”

Nothing.

Please, God, please, if you won’t give me anything else, at least let me tell her good-bye. He’s never answered Noemi before, but if he does now, she’ll believe forever. I have to tell her good-bye.

The sensors flatline. Esther is gone.

In the very next instant, every computer interface in sick bay brightens to full illumination. The damned mech brought power back online just as soon as it was too late to save Esther.

Noemi stands as if frozen, staring down at Esther. Her eyes well with tears, but it’s like they’re crying without her. Instead of sobbing or shaking, she feels as if she’ll never move again.

She’s in heaven now. Noemi should believe that. She does, mostly, but the knowledge doesn’t comfort her. The words only echo in the hollow space that has replaced her heart. She finds herself remembering her family’s funeral more vividly than she has in years—the high winds that blew, tugging at everyone’s hair and clothes, and stealing the priest’s words before Noemi could really hear them. The way Noemi stared down into the grave and tried to imagine her parents lying there, baby Rafael between them, looking up at the sky for the last time before they were covered by dirt forever. More than anything else, she remembers Esther standing near her, all in black, crying as hard and loud as Noemi herself. Years later Esther had revealed that she made herself cry, so Noemi wouldn’t be alone.

Now Esther’s gone, too, and instead of being held close and told she was loved, she had to die listening to Noemi shriek at someone in anger. That ugly moment was the last one Esther ever knew.

It’s dangerous—being angry at God—but Noemi can’t deny the bitter rage she feels at this one last proof that she isn’t enough for God, for the Gatsons, for anyone at all.

The long silence is broken by Abel’s voice. “I didn’t attempt resuscitation because failure was all but certain. Her internal blood loss was too great. We would’ve had to begin the transfusion much earlier to save her.”

“Or we could’ve gotten her into cryosleep.” Noemi turns to stare at the mech. He stands near the computer interface, very still, so obviously unsure what to do that he looks almost human. This doesn’t move her; it enrages her. “If you hadn’t wasted time trying to kill me, Esther might still be alive! We could have put her into cryosleep and saved her!”

Abel doesn’t respond at first. But finally he says, “You are correct.”

As many times as Noemi has gone into battle against Earth forces—as many times as she’s seen friends and fellow soldiers torn apart by their mechs—she thought she knew how to hate with her whole heart. But she didn’t.

Now, only now, as she stares at the machine responsible for her best friend’s death, does Noemi feel what hatred really is.

Abel’s programming covers many situations involving interpersonal conflict.

Not this one.

The Genesis warrior—the dead one called her Noemi—stands next to the corpse, shaking with anger. Like all mechs, he has been constructed to endure human wrath in both its emotional and physical forms, and yet he finds himself uncertain. Wary. Even … worried.

Noemi has command over him unless and until he is released by someone with the authority to override her. Therefore, her power over him is all but absolute. It doesn’t matter that he could outrun her, outshoot her, that he could kill her with a single hand: He cannot defend himself against her any more than he can disobey her. Abel is at his commander’s mercy.

She takes a deep breath, stops trembling, and goes very still. He isn’t sure how, but he knows that’s worse.

“Where’s the nearest air lock?” Noemi asks.

“The equipment pod bay approximately halfway down the main ship’s corridor.” In other words, the cell in which Abel just spent the past three decades. Noemi seems unlikely to be interested in this information, so he says nothing else.

Noemi nods. “Walk toward it.”

Abel does so. She follows a few steps behind. Although she could potentially have many reasons for needing an air lock, he immediately understands which of her potential purposes is most likely—namely, his destruction. She will release him into the cold void of space, where he will cease operations.

Not instantaneously. Abel is built to withstand even the near-absolute-zero temperatures of outer space … for a time. But within seven to ten minutes, the damage to his organic tissues will be permanent. Total mechanical malfunction will swiftly follow.

He isn’t afraid to die. And yet, as he walks along the corridor to his doom, his executioner’s steps echoing behind him, Abel feels that this is wrong. Unjust, somehow.

Is this another of his strange emotional malfunctions? Perhaps his pride is occupying too large a part of his thoughts, because it galls Abel to think that he—the most complex mech ever created—is about to be tossed out an air lock like human refuse, for no reason other than the pique of an unhappy Genesis soldier.

After some consideration, he decides that yes, his pride is interfering with effective analysis of the situation. He is from Earth, and therefore he is this girl’s enemy. Although he knows how powerfully his programming controls him, she probably doesn’t trust it. If Genesis has held true to its anti-technology stance, then Noemi has probably never been in the same room with a mech before. She’d only have met them in battle. No wonder she finds him frightening. Taking into account the fact that he attacked and very nearly killed her not half an hour before, her decision to space him appears more reasonable. Almost logical.

That doesn’t make him feel any better about it.

When Abel reaches the equipment pod bay, he steps without hesitation through the door he was so grateful to escape not even an hour ago. He can see the irony of having been freed from this place only to come back here to die. In his mind he finds himself running through scenarios, possibilities—the seven different ways he could kill the Genesis soldier this instant. Why?

Then Abel realizes what it is: It’s not that he doesn’t want to die. It’s that he wants to live.

He wants more time. To learn more things, to travel through the galaxy and see all the colony worlds of the Loop, to return back home to Earth for at least one day. To find out what has become of Burton Mansfield and perhaps speak with his “father” once more. To watch Casablanca properly again instead of merely retelling himself the story. To ask more questions, even if he never gets the answers.

But what a mech wants doesn’t matter.

No image caption or credit.

Abel turns to face Noemi before she can hit the controls that will seal this door, allowing her to open the outer hatch and vent him into space. He went so long without seeing a human face or speaking to anyone. It helps him to look at her, even if that means watching her take the steps that will kill him. Although he doesn’t expect this to affect her in any way, her dark-brown eyes widen when they’re face-to-face again.

Noemi doesn’t speak. She lifts her hand to the control panel … and does nothing.

Seconds tick by. When Abel judges that this pause has gone on an inordinately long time, he ventures, “Do you need help understanding the controls?”

“I understand the controls.” Her voice is thick from the tears she’s still holding back.

Abel cocks his head. “Have I misinterpreted your purpose in bringing me here?”

“What do you think my purpose is?”

“To space me.”

“You got it.” Her smile is twisted by grief. “That’s why we came here.”

“Then may I ask why you have not yet done so?”

“Because it’s stupid,” Noemi says. “Hating you. I want to hate you because you might’ve saved Esther and you didn’t—but what’s the point? You’re not a person. You don’t have a soul. You obey your programming, because you have to, and without free will there can be no sin.” She breathes out sharply in frustration, looks up at the ceiling as if that will keep the tears from trickling beyond her eyes. “I might as well hate a wheel.”

A few more seconds elapse before Abel feels emboldened to say, “May I now step out of the air lock door?”

Noemi moves back, making room for him. This reads as permission, and so Abel steps out of the equipment pod bay with profound relief. Only then does Noemi hit the controls, once again sealing off the bay.

He offers, “If you would feel safer with me immobilized, the cryosleep pods would be effective. Mechs cannot be put in true cryosleep, but exposure to the chemicals activates our dormant mode.”

“I don’t need you to be dormant. I need you to be useful.” She wipes at her eyes, attempts to act like the soldier she is. “We’ll—I’ll take care of Esther later. First I have to make a plan. Wasn’t the bridge back that way?”

“Yes, ma’am.”

She winces. “Please don’t call me that.”

She’s still pulling herself together. “My name is Noemi Vidal.”

“Yes, Captain Vidal.”

“Noemi’s fine.” She turns and trudges toward the bridge. Her voice is hoarse, her exhaustion and grief obvious, but she remains focused on survival. “Follow me, Abel.”

She’ll let me use her first name, Abel thinks. No human being has ever allowed him that much liberty before. The thought pleases him, though he can’t determine why.

Nor does he know the reason why he glances over his shoulder, back at the equipment pod bay he has escaped twice today. Surely after thirty years he has seen enough of it.

Perhaps it’s just because it feels so good to leave that place behind.

This is the navigational position for the pilot, right?” Noemi runs her hands through her hair as they stand on the Daedalus’ bridge. The curved walls allow the ship’s viewscreen to wrap almost entirely around and above them, displaying the surrounding starfield in such detail that the bridge appears to be a dull metallic platform in the middle of outer space. “The captain’s chair is obvious, and I figure this is for external communications. And that’s the ops station.”

“Correct. Your technological sophistication is surprising for a soldier of Genesis.”

She turns toward him, frowning. “We limit technology by choice, not out of ignorance.”

“Of course. But in time, the first must inevitably lead to the second.”

“Why do you have to act so superior?”

Abel considers her assertion. “I am superior, in most respects.”

Noemi’s hands close around the back of the captain’s chair, gripping it too hard, and when she speaks again, she grinds out every word. “Could you. Knock it. Off.”

“Modesty is not one of my chief operating modes,” he admits, “but I will try.”

She sighs. “I’ll take what I can get.”

No image caption or credit.

He assesses her as she paces the length of the bridge, her formfitting emerald-green exosuit outlining her athletic body vividly against the blackness of space. Amid the stars glow the larger, gently shaded planets of the Genesis system. Abel can make out the circle that is Genesis itself, brilliant green and blue, with its two moons visible as tiny pinpoints of white.

“Do we have fuel?” Noemi asks. “Can the Daedalus get back home?”

Abel replies, “Fuel stores are sufficient for full-ship operations lasting two years, ten months, five days, ten hours, and six minutes.” He leaves out the seconds and milliseconds. “The ship took damage in its final battle, but the damage doesn’t appear to have been extreme.” Hardly even threatening. He frowns at the readouts scrolling past on the console. Did Captain Gee panic? Did she convince Mansfield to abandon ship when there was no real need? “Travel through a Gate would be difficult—”

“We’re not going through a Gate. We’re going home.”

Of course. Earth is Abel’s home, not Noemi’s. He continues, “After minor repairs with instruments we have on hand, we should be able to reach Genesis without difficulty.”

“Good.”

What will become of him on Genesis? Will he be dismantled? Sent back out into space? Made to serve in their armies? Abel cannot guess, and thinks it would be a bad idea to ask. He has no control over the situation. He may as well learn his fate when it comes to pass.

Noemi sits heavily in the nearest chair, the one at the ops station, which like all the stations aboard the Daedalus is thickly padded and covered with soft black material. Running her hand along it, she frowns. “Was this some kind of luxury cruiser or something? Regular Earth ships can’t all be like this … can they?”

“The Daedalus is a research vessel, customized especially for its owner and my creator, Burton Mansfield.”

“Did you say Burton Mansfield?” She sits up straight and gapes at him. “The Burton Mansfield?”

At last. It’s good to see Noemi finally responding with appropriate awe. “The founder and architect of the Mansfield Cybernetics line? Yes.”

He watches for her reaction, anticipating her amazement—and instead sees her scowl. “That son of a bitch. This is his ship? You’re his mech?”

“… yes.” How dare she call his father such names? But Abel can’t object, so he forces himself not to think of it any longer.

“I can’t believe it,” Noemi mutters. “You’re telling me Mansfield himself came to this system thirty years ago, and he got away?”

“All humans aboard abandoned ship,” Abel answers as simply as he can. “As I wasn’t on the bridge at that time, I cannot know how successful their escape was, nor their reasons for abandoning a functional ship.”

“We scared them. That’s why they ran.” Energized, Noemi gets to her feet and reexamines every station on the bridge, as if it requires further consideration now that she knows who it belongs to. “But why would Burton Mansfield come to the Genesis system to start with? Why would he throw himself into the middle of a war?”

And there it is—the question Abel had hoped Noemi would not think to ask.

As long as she’s his commander, he cannot lie to her. However, he has enough discretion to … omit certain facts, as long as her questions are not direct.

He tries indirection first. “Mansfield had undertaken critical scientific research.”

“In a war zone? What was he researching?”

A direct question: Full disclosure is now required. “Mansfield was studying a potential vulnerability in the Gate between Genesis and Earth.”

Noemi goes very still. She’s realizing the true significance of what she’s found. “By vulnerability—do you mean a potential malfunction, or—tell me, exactly, what?”

Abel remembers the day Mansfield realized the worst. The endless hours of research and sensor readings required, the immense leap of insight it took for Mansfield to grasp the answer: All of this, Abel now has to deliver to a soldier of Genesis. “By vulnerability, I mean he was investigating a way a Gate could be destroyed.”

Noemi’s face lights up. Under different circumstances, Abel would be pleased to have brought his commander so much joy. “Did you find one?”

They ought to have foreseen it, Abel thinks. They shouldn’t have left me here. It was … tactically unwise.

Because I have no choice but to betray them.

“Answer me,” Noemi says. “Did you find a way to destroy a Gate?”

He’s lying.

Noemi knows the mech—Abel—can’t lie to her while she’s his commander, which somehow she is. But the enormity of what he’s said makes it feel like the ship’s gravity is shifting beneath her feet, forcing her off-balance. Her grief for Esther weighs on her too heavily to allow for the sudden, staggering return of hope.

“How?” She takes one step toward Abel. The viewscreen dome shows re-fog trails of the galaxy’s arm, stretching their glowing tendrils overhead. “How can anyone destroy a Gate?”

“Gates are capable of creating and stabilizing wormholes, which are essentially shortcuts in space-time,” he begins, talking down to her again. “When a wormhole is fully stable, a ship can travel through, thereby crossing enormous distances in an instant.”

The Masada Run will destabilize the Genesis Gate, but only for a while. Months, probably. Two or three years, if they’re lucky. Possibly just a matter of weeks. All those lives, including her own, will be spent for the mere chance that Genesis might gain an opportunity to rebuild and rearm itself, to beat their plowshares into swords, and then to plunge back into a war that they almost certainly can’t win.

Abel continues, “A wormhole can only be permanently stabilized through the use of so-called exotic matter. In the Gates, this exotic matter takes the form of supercooled gases kept even colder than the space beyond it, mere nanokelvins above absolute zero.”

Colder than outer space. Noemi has tried to imagine that before, but she can’t. The intensity of that chill is beyond any human reckoning.

Abel continues, “These gases are cooled by magnetic fields generated by several powerful electromagnets that make up the components of the Gate—”

“But all those components—they’re programmed to reinforce one another. It’s almost impossible to destroy one while the others are backing it up.”

He cocks his head. “You understand more about the components of a Gate than I would have thought.”

“To judge by the extremely outdated and dilapidated condition of your current ships and armaments, Genesis appears to have all but abandoned scientific and technological advancement.”

From anyone else, that would be an insult. From Abel, it’s a simple, factual assessment. The insult would’ve been easier to take. “Apparently not, because I understand how a Gate works. Which means I know they’re supposed to be invulnerable. You say they’re not. How do we destroy one?”

He hesitates, and his reluctance is uncannily genuine. Too genuine, in Noemi’s opinion; Mansfield was showing off with this one. “Most efforts to damage or destroy a Gate are targeted at destroying the magnetic fields inside. However, it is not necessary to destroy the fields to collapse the Gate. Only to disrupt them.”

Noemi shakes her head. “But we can’t even manage that, not with every component supporting one another.”

“You’ve failed to see the obvious alternative.” Abel catches himself. “You shouldn’t feel that this failure reflects negatively on you. Relatively few humans are capable of the insight necessary to—”

“Just tell me.”

“Disrupting the fields doesn’t have to mean weakening or destroying them. It can also mean strengthening them.”

She opens her mouth to object. Strengthen it? How can making the Gate stronger possibly help them? Then the answer takes shape in her mind. “Strengthening the fields would warm the gases inside. When the exotic matter becomes too warm, the Gate will implode.”

Abel inclines his head, not quite a nod. “And destroy the wormhole forever.”

Noemi sinks into the nearest station, overwhelmed by the possibilities and problems she now sees. “But—any device powerful enough to overcome the Gate’s magnetic fields—where would we get that? Do any of those even exist?”

“There are thermomagnetic devices capable of creating that level of heat on their own. Not many, of course. The practical applications are limited.”

“But they are out there? We could find one?”

“Yes.”

She wants to hope—wants it so badly she can taste it—but Noemi can see all the problems with this plan already. “You’d have to activate it on the verge of the Gate. Otherwise the heat would melt your ship before you even reach the Gate. And you can’t just launch it remotely either. You’d have to have a pilot to work around the Gate’s defenses.”

“You understand a great deal about piloting for someone from a planet that has stubbornly refused to go anywhere.”

And that reminds her of the guilty longings she sometimes feels when she sees the speed of Earth ships, the complexity of the Gate, even the inhuman reflexes of their mechs. Noemi doesn’t want to be like people from Earth, but … she can’t help wanting to know what they know. To discover. To explore.

Her next flash of insight eclipses all those old dreams in an instant. “No human could do it. A human pilot would lose control or die from the heat too quickly.”

“True. Also, even if the human pilot could succeed, the Gate’s implosion would kill her instantly.”

Noemi hadn’t bothered worrying about that. Collapsing the Gate—saving her world—it’s worth one life. Her willingness to make that sacrifice is irrelevant if she would only fail. But there’s another possibility. “A mech could do it, right?”

Abel hesitates before answering, just long enough for her to be aware of it. “Not most mechs. They’re programmed to go into basic utility mode during self-damaging tasks. You’d need an advanced model. One capable of thinking even at the point of destruction.”

He straightens. “Yes.”

Abel clearly has no instinct for self-preservation that overrides the orders given by his commander. The air lock proved that. If she tells him to destroy the Gate and be destroyed along with it, he will.

Noemi would gladly lay down her life to save Genesis. So she can ask a mech to give up … whatever it is he has.

Slowly she rises from the chair. The projected starlight shines softly around her, making the moment even more dreamlike than it already is.

Her only plan had been steering the Daedalus toward Genesis and bringing Esther’s body home. She’d had a vague idea of turning the ship and the mech over to her superior officers, in case they could be used in the war effort. Some small contributions that would outlive her, that could go on serving after the Masada Run.

Instead she’s found a mech not only aware of how to destroy a Gate but also capable of helping her do it. And a ship that could take her through the Loop to find the device she needs—Earth would come after any Genesis ship, she thinks, but they won’t be on the lookout for this one. This could actually work.

It means throwing herself through the galaxy, to planets she’s never seen before. It means risking her life, maybe even winding up in an Earth prison, defeated and helpless—which would be so much worse than dying in the Masada Run. It means leaving Genesis behind, maybe forever.

She turns to Abel. “We’re going to destroy this Gate.”

“Very well,” he replies as easily as if she’d asked him the time. “We should run an in-depth diagnostic on the Daedalus. Although my initial scans indicate that she remains fully fueled and in good condition, we will want to be certain of that before we begin to travel. It should take no more than an hour or two.”

It startles her that he understands they’re about to travel through the Gates to other worlds, but of course he does. Abel would’ve realized the implications as soon as he explained the Gate’s flaw to her. However, there’s one thing he doesn’t understand yet. “We have to wait.”

Abel gives her a look. “So you want to end a deadly and destructive war, but there’s … no rush?”

Noemi’s not sure why Mansfield decided to give a mech the capacity for sarcasm. “I’m only an ensign,” she says, tapping the single gray stripe on the cuff of her green exosuit sleeve. “This mission—it’s risky, and there could be drawbacks I haven’t seen—”

“I would have seen them.” His expression is so smug that Noemi wishes she had something in her hands to throw at him.

“Yeah, well, you’re Burton Mansfield’s mech. So forgive me if I don’t trust you completely.”

“If you don’t trust me, why are you undertaking this mission on my word alone?” Abel seems almost irritated. “If I could lie to you about the risks, I could also lie to you about the potential.”

That’s not a bad point, but Noemi doesn’t bother justifying herself to a mech. “My point is, I should run this by my superior officers if I can.”

“Do you wish to fly directly to Genesis?” Noemi opens her mouth to give the order, then thinks better of it. Yes, she should run this by Captain Baz at least—probably the whole Elder Council. She can imagine standing in their white marble chamber in her dress uniform, looking up at Darius Akide and the other elders, showing them this one chance they have to save their world.

And she can imagine them saying no.

They might not trust Abel’s word. What would it take to convince the Elder Council? They’re so sure the Masada Run is the only way—

She thinks about the various speeches that have been given, the vids they’ve seen in support of the Masada Run. Sacrifice your lives, they say. Sacrifice your children. Only through sacrifice can Genesis survive.

Now she’d be coming back to tell all of Genesis and the Council that there’s another way out. That the Masada Run isn’t necessary and never was. She, Noemi Vidal, a seventeen-year-old ensign, orphaned and newly friendless, backed up only by a mech.

Would the Elder Council even believe her? Worse, would they refuse to back down just to avoid admitting they were wrong?

It’s not that Noemi never doubted the Council before—but this is the first time she’s ever allowed herself to think that they might fail her world so completely. She’s not sure she really believes they would. But they could, and that risk alone is enough.

“Belay that order,” she says slowly. “Run the diagnostic. See if the ship’s ready to travel through the Gates.”

Abel raises one eyebrow. “Does that mean we’re proceeding without approval from your superiors?”

Noemi’s been taking orders her whole life. From the Gatsons, because they were good enough to take her into their family and deserved her obedience. From her teachers, from her commanding officers. She’s tried to obey all of them and the Word of God, too, despite all her doubts and confusion, putting aside her own dreams, because that’s her duty.

But her duty to protect Genesis goes beyond any of that.

“Yes,” Noemi says, staring out at the stars that will guide her. “We’re going to destroy the Gate on our own.”

To save her world, she must learn to stand alone.

Stem Education Coalition

Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

## From Nautilus: “Gravity’s Kiss – The third ripple.

Nautilus

3.5.17
Harry Collins

Caltech/MIT Advanced aLigo Hanford, WA, USA installation

Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

VIRGO Gravitational Wave interferometer, near Pisa, Italy [not yet operational]

Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib

Gravitational waves are finding their way to the general public. There is massive television news coverage with never a doubt expressed; gravitational waves have simply “been detected”—exciting but no more dubious than, say, the moon landing. What is happening is that gravitational waves are being “domesticated” in the same way as black holes or the Higgs have been domesticated. Everyone knows what a black hole is—it is a feature of everyone’s day-to-day life embedded in a “semantic net” that includes “the cosmos,” “the big bang,” “Stephen Hawking,” “brilliant scientists,” “Einstein,” “space,” “alternative universes,” “time travel,” “worm-holes,” “astronomy,” “rockets,” and “being sucked into things”—and this is in spite of the fact that, before The Event, no black hole had been observed except by inference. As for the Higgs, everyone knows that it was found by the huge and brilliant team at CERN, but, familiar as it is, no one knows what it is. I know it is the last piece in the jigsaw puzzle of the particle “zoo” known as the standard model, but what I have is “beer-mat knowledge,” good for answering questions in Trivial Pursuit but that’s about it. On the other hand, the fact that we can imagine encountering questions about black holes and the Higgs while playing Trivial Pursuit is one of the things that makes them real: all this familiar knowledge makes stuff real. The moon landing, note, is pretty real for everyone but, just as in the case of what is building in respect of The Event, there are conspiracy theories about that too; and, just as in this case, you have to stray from the mainstream to find them.

On Friday I gather a good selection of the United Kingdom print newspapers; they are big contributors to the domestication process. The Guardian is a broadsheet for the left-liberal middle classes and its news section is 38 pages long. It gives the story the lead and whole of page 11. It had also given it the whole of page 3 on Wednesday, building the story on the rumors. On Saturday, The Guardian’s regular political cartoon features the Syrian peace talks represented as some kind of funny-looking celestial object with the caption: “Not gravitational waving but gravitational drowning.” Thus do gravitational waves spread into the ordinary language.

EXTRA! EXTRA!Newspaper front pages from around the world.
Courtesy of LIGO

The Independent has a similar readership to The Guardian but has a smaller tabloid format with 72 pages. It gives the story the entire page 1 and pages 6–8; it opines that this is “one of the greatest achievements in human history.”

The Telegraph is another broadsheet, with 38 pages in its news section. It is a right-wing, patriotic paper for the educated. It makes gravitational waves the second story on page 1, leading with:

A British scientist who was pivotal in the project to detect gravitational waves could not celebrate the momentous discovery with colleagues because he is suffering from dementia.

This, of course, is Ron Drever. The paper also gives up pages 10 and 11 to the story.

Martin Rees, the Astronomer Royal, writes columns in The Independent and the Telegraph. He opines that this is of similar importance to the discovery of the Higgs; most other commentators say it is much more important than the Higgs, but Rees has long been said by gravitational wave physicists to be less than enthusiastic about the enterprise.

The Daily Mail is a “little Englander” tabloid with 92 pages serving those with strong right-wing opinions. It gives the story half of page 10, mistakenly claiming that Einstein predicted that colliding stars would generate gravitational waves that could be detected on Earth, whereas he actually thought they would remain completely undetectable.

The Mirror is a left-leaning tabloid with 80 pages. It gives the story most of page 21 but says that LIGO was invented by Thorne and Weiss, missing out on Drever.

The Sun is a tabloid with 60 pages that began its life by publishing photographs of topless models on the notorious “page 3” (now dropped). The only science I could find was on the bottom third of page 15, head-lined: “Top Prof Dies in Rubber Suit with Dog Lead Round Neck.” The “Top Prof” does not seem to have been one of the gravitational wave team.

The Guardian website of February 12 includes a hilarious cartoon—one of a series called “First Dog on the Moon,” which anticipates one of my major sociological theses. The fourth panel of the cartoon opines:

Obviously we can’t see these waves—the only way we know they are real is by using another extremely sensitive device which detects scientists having feelings of excitement.

The excitement evoked in scientists by a gravitational wave is calibrated using the marginally smaller effect of a cheese salad sandwich as a standard candle.

Later I will discover that my major thesis about social construction, which turns on pointing out that no gravitational waves were seen but merely a few numbers that were interpreted as gravitational waves, has been thoroughly anticipated (albeit on a strange, flat-earther YouTube channel that appears to treat conspiracy theories as an art form). It claims scientists have not seen gravitational waves, nor has their machine seen gravitational waves, but that the machine produces lots of glitchy noises out of which they have picked one and interpreted it as a gravitational wave.

A member of the LIGO team has put together a collection of newspaper front pages from around the world. And, as though to put an indelible stamp on the soon to be taken for granted nature of this exotic phenomenon, in the United States the discovery is presented on Saturday Night Live and The Tonight Show, and, on Saturday, February 13, the humorous U.S. radio show A Prairie Home Companion devotes about five minutes to gravitational waves. Gravitational waves have arrived!

The physicists continue to do my job for me by gathering more indications of the domestication of gravitational waves. On February 16, a French (presumably humorous) website normalizes the waves in contemporary fashion by calling for a ban on them and the distribution of protective helmets. This is a Google translation from the French with my minor edits:

“For a Moratorium on Gravitational Waves

Bringing together hundreds of independent researchers, the “Collective for a moratorium on gravitational waves” (COMOG) sent us this platform. We publish it verbatim in our columns:

In recent days, highlighting the “gravitational waves” continues to make the press headlines. Everyone welcomes this alleged “scientific breakthrough,” which was published in the Physical Review Letters, a journal under orders of the nuclear lobby.

Now, our collective, consisting of independent researchers who wish to remain anonymous for their own reasons, is concerned about the apparent toxicity of gravitational waves.

To date, there is in fact no serious study establishing the actual safety of these waves. That is why we propose an action plan of four points.

1. We recall, first, that the oscillations of the curvature of space-time can present health risks found, especially on the neurological system of employees too long exposed to the gravitational waves. It is appropriate in this case to call for the government to strictly enforce the Labour Code, to limit the time of exposure to gravitational waves, and equip the wage earners with protective helmets.

2. To these health risks are added, as often environmental, of deleterious economic effects. The curvature of space-time is likely to cause untoward inconvenience, especially in the field of transport and travel. An example: If space-time is curved in the wrong direction when one performs a trip from Paris to Bordeaux, the journey can last more than 25 hours, according to our estimates. Gravitational waves expose the French economy to serious danger that cannot be underestimated.

3. It appears that the production of gravitational waves calls for masses of matter and energy that are absolutely astounding: black holes, neutron stars, washing machines, etc. We ask that the environmental and climate impact of gravitational waves be measured in France by an independent body and a carbon footprint be determined as quickly as possible.

4. As a result, we ask Ségolène Royal, Minister of Environment, Energy and the Sea, responsible for international relations on the climate, to apply the constitutional principle of precaution, and to take by decree related measures that are defined and recommended in principle 15 of the Rio Declaration. It seems to us urgent that France decide on a moratorium on gravitational waves.

If the government does not abide by these basic precautions, peaceful COMOG teams will be forced to resort to direct action. Within six months, we will proceed to the systematic dismantling of gravitational wave antennas. Our teams of volunteer harvesters shall uproot the plants of space-time curvatures. Finally, we will not hesitate to leave Paris to set up a zone to defend Proxima Centauri, even against the advice of the prefect.

We call upon our fellow citizens to join our fight. Gravitational waves, no thank you!”

On February 18, the Huddersfield Daily Examiner (Huddersfield is a town in North England with a football club—“Huddersfield Town”—all about as provincially English as can be) carries a story about the “Huddersfield Town Supporters Association” (HTSA). It includes:

Our HTSA column last week touched upon the subject of regional supporters groups and their recent cosmic rise in popularity. The Laser Interferometer Gravitational-Wave Observatory (LIGO) can probably demonstrate whether this is due to colliding Black Holes over Bexleyheath.

And Barack Obama had tweeted on February 11:

Einstein was right! Congrats to @NSF and @LIGO on detecting gravitational waves—a huge breakthrough in how we understand the universe.

At the forthcoming American Physical Society (APS) meeting, Dave Reitze, the director of LIGO, will present a slide showing a woman wearing a dress patterned with the waveform, an Australian competition swimmer with the waveform on his swim-cap, and a New York advertisement for apartments.

Fashionably wavy. More domestication of gravitational waves. No image credits.

I attend two meetings in March: a general relativity 100th anniversary meeting at Caltech and the LIGO-Virgo collaboration meeting in Pasadena. Of course, the cat is now out of the bag so a big topic at the Caltech meeting is The Event. I follow Barry Barish onto the platform; he describes the technicalities and I talk about the way small science and big science had combined to create this possibility, with Barish bringing about the necessary transformation, and I talk about what it meant for me as a sociologist to be confronted by such a sudden and certain result. At neither meeting is there any criticism but the LVC is selling huge numbers of T-shirts and polo shirts with the waveform of The Event printed or embroidered on them: The waveform is becoming an icon! Many more such garments will be sold at the April APS meeting.

At the March meeting of the APS—a much larger meeting than the April meeting I am going to attend—a group of physicists who have nothing to do with LIGO or gravitational waves performed a song based on the Neil Diamond/Monkees’ “I’m a Believer.” The lyrics are as follows:

“I’m a LIGO Believer.” Lyrics: Marian McKenzie. Tune: “I’m a Believer,” by Neil Diamond (courtesy Marian McKenzie).

I thought waves of gravity were fairy tales—fine for dilettantes, but not for me.
What’s the use of searching?
Noise is all you’ll find.
I don’t want to clutter up my mind—

[Chorus:] Then I saw the graph—Now I’m a believer!
You can laugh, and hold me in scorn.
I’m convinced, oooh, I’m a believer
In Weiss, Reitze, Drever, Gonzalez, and Thorne!

Einstein spoke of grav wave propagation.
Weber tried to find them on the moon.
BICEP2 announced them,
Then said “Never mind.”
—Do you wonder I was disinclined?

[Sing chorus] [instrumental interlude] and repeat”

The whole song can be seen and heard on YouTube.

surfing the googleEnormous spike in interest in gravitational waves around February 11. No image credit.

What about social media? Google Trends (see chart above) shows the huge spike in interest in gravitational waves around the February 11 press conferences by tracking hits on Google. Unfortunately, we have only the normalized trend, the scale having a maximum of 100, not absolute numbers.

Breaking the internet. The enormous spike in interest in gravitational waves compared to hits for Kim Kardashian.

Gravitational waves are not, however, about to take over the popular imagination. The chart above shows the same spike in comparison to Google hits for Kim Kardashian, the reality TV star. Gravitational waves’ enormous spike is a mere 2 percent as high as Kardashian’s peak performance and only about 5 percent as high as her average day-to-day score. Aside from the spike, gravitational waves score zero when compared to Kardashian’s average.

Stem Education Coalition

Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

## From Nautilus: “The Physicist Who Denies that Dark Matter Exists”

Nautilus

3.1.17
Oded Carmeli

Mordehai Milgrom Credit: Weizmann Institute

Maybe Newtonian physics doesn’t need dark matter to work, but Mordehai Milgrom instead.

He is one of those dark matter people,” Mordehai Milgrom said about a colleague stopping by his office at the Weizmann Institute of Science. Milgrom introduced us, telling me that his friend is searching for evidence of dark matter in a project taking place just down the hall.

“There are no ‘dark matter people’ and ‘MOND people,’” his colleague retorted.

“I am ‘MOND people,’” Milgrom proudly proclaimed, referring to Modified Newtonian Dynamics, his theory that fixes Newtonian physics instead of postulating the existence of dark matter and dark energy—two things that, according to the standard model of cosmology, constitute 95.1% of the total mass-energy content of the universe.

This friendly incident is indicative of (“Moti”) Milgrom’s calmly quixotic character. There is something almost misleading about the 70-year-old physicist wearing shorts in the hot Israeli summer, whose soft voice breaks whenever he gets excited. Nothing about his pleasant demeanor reveals that this man claims to be the third person to correct Newtonian physics: First Max Planck (with quantum theory), then Einstein (with relativity), now Milgrom.

This year marks Milgrom’s 50th year at the Weizmann. I visited him there to learn more about how it feels to be a science maverick, what he appreciates about Thomas Kuhn’s The Structure of Scientific Revolutions, and why he thinks dark matter and dark energy don’t exist.

What inspired you to dedicate your life to the motion of stars?

I remember very vividly the way physics struck me. I was 16 and I thought: Here is a way to understand how things work, far beyond the understanding of my peers. I was drawn to the beauty of finding deeper reasons for events, to the aesthetics of discovering hidden symmetries. It wasn’t a long-term plan. It was a daily attraction. I simply loved physics, the same way other people love art or sports. I never dreamed of one day making a major discovery, like correcting Newton.

I had a terrific physics teacher at school, but when you study textbook material, you’re studying done deals. You still don’t see the effort that goes into making breakthrough science, when things are unclear and advances are made intuitively and often go wrong. They don’t teach you that at school. They teach you that science always goes forward: You have a body of knowledge, and then someone discovers something and expands that body of knowledge. But it doesn’t really work that way. The progress of science is never linear.

How did you get involved with the problem of dark matter?

Toward the end of my Ph.D., the physics department here wanted to expand. So they asked three top Ph.D. students working on particle physics to choose a new field. We chose astrophysics, and the Weizmann Institute pulled some strings with institutions abroad so they would accept us as postdocs. And so I went to Cornell to fill my gaps in astrophysics.

After a few years in high energy astrophysics, working on the physics of X-ray radiation in space, I decided to move to yet another field: The dynamics of galaxies. It was a few years after the first detailed measurements of the speed of stars orbiting spiral galaxies came in. And, well, there was a problem with the measurements.

To understand this problem, one needs to wrap one’s head around some celestial rotations. Our planet orbits the sun, which, in turn, orbits the center of the Milky Way galaxy. Inside solar systems, the gravitational pull from the mass of the sun and the speed of the planets are in balance. By Newton’s laws, this is why Mercury, the innermost planet in our solar system, orbits the sun at over 100,000 miles per hour, while the outermost plant, Neptune, is crawling at just over 10,000 miles per hour.

Now, you might assume that the same logic would apply to galaxies: The farther away the star is from the galaxy’s center, the slower it revolves around it; however, while at smaller radiuses the measurements were as predicted by Newtonian physics, farther stars proved to move much faster than predicted from the gravitational pull of the mass we see in these galaxies. The observed gap got a lot wider when, in the late 1970s, radio telescopes were able to detect and measure the cold gas clouds at the outskirts of galaxies. These clouds orbit the galactic center five times farther than the stars, and thus the anomaly grew to become a major scientific puzzle.

One way to solve this puzzle is to simply add more matter. If there is too little visible mass at the center of galaxies to account for the speed of stars and gas, perhaps there is more matter than meets the eye, matter that we cannot see, dark matter.

MOND in the MakingMilgrom’s notes from 1981. On the left, each line represents the data from a separate galaxy. On the right is the MOND prediction, which is the line going through the data points.
Mordehai Milgrom

What made you first question the very existence of dark matter?

What struck me was some regularity in the anomaly. The rotational velocities were not just larger than expected, they became constant with radius. Why? Sure, if there was dark matter, the speed of stars would be greater, but the rotation curves, meaning the rotational speed drawn as a function of the radius, could still go up and down depending on its distribution. But they didn’t. That really struck me as odd. So, in 1980, I went on my Sabbatical in the Institute for Advance Studies in Princeton with the following hunch: If the rotational speeds are constant, then perhaps we’re looking at a new law of nature. If Newtonian physics can’t predict the fixed curves, perhaps we should fix Newton, instead of making up a whole new class of matter just to fit our measurements.

If you’re going to change the laws of nature that work so well in our own solar system, you need to find a property that differentiates solar systems from galaxies. So I made up a chart of different properties, such as size, mass, speed of rotation, etc. For each parameter, I put in the Earth, the solar system and some galaxies. For example, galaxies are bigger than solar systems, so perhaps Newton’s laws don’t work over large distances? But if this was the case, you would expect the rotation anomaly to grow bigger in bigger galaxies, while, in fact, it is not. So I crossed that one out and moved on to the next properties.

I finally struck gold with acceleration: The pace at which the velocity of objects changes.

We usually think of earthbound cars that accelerate in the same direction, but imagine a merry-go-round. You could be going in circles and still accelerate. Otherwise, you would simply fall off. The same goes for celestial merry-go-rounds. And it’s in acceleration that we find a big difference in scales, one that justifies modifying Newton: The normal acceleration for a star orbiting the center of a galaxy is about a hundred million times smaller than that of the Earth orbiting the sun.

For those small accelerations, MOND introduces a new constant of nature, called a0. If you studied physics in high school, you probably remember Newton’s second law: force equals mass times acceleration, or F=ma. While this is a perfectly good tool when dealing with accelerations much greater than a0, such as those of the planets around our sun, I suggested that at significantly lower accelerations, lower even than that of our sun around the galactic center, force becomes proportional to the square of the acceleration, or F=ma2/a0.

To put it in other words: According to Newton’s laws, the rotation speed of stars around galactic centers should decrease the farther the star is from the center of mass. If MOND is correct, it should reach a constant value, thus eliminating the need for dark matter.

I didn’t share these thoughts with my colleagues at Princeton. I was afraid to come across as, well, crazy. And then, in 1981, when I already had a clear idea of MOND, I didn’t want anyone to jump on my wagon, so to speak, which is even crazier when you think about it. Needless to say,” he laughs, “no one jumped on my wagon, even when I desperately wanted them to.

Well, you were 35 and you proposed to fix Newton.

Why not? What’s the big deal? If something doesn’t work, fix it. I wasn’t trying to be bold. I was very naïve at the time. I didn’t understand that scientists are just as swayed as other people by conventions and interests.

Like Thomas Kuhn’s The Structure of Scientific Revolutions.

I love that book. I read it several times. It showed me how my life’s story has happened to so many others scientists throughout history. Sure, it’s easy to make fun of people who once objected to what we now know is good science, but are we any different? Kuhn stresses that these objectors are usually good scientists with good reasons to object. It is just that the dissenters usually have a unique point of view of things that is not shared by most others. I laugh about it now, because MOND has made such progress, but there were times when I felt depressed and isolated.

What’s it like being a science maverick?

By and large, the last 35 years have been exciting and rewarding exactly because I have been advocating a maverick paradigm. I am a loner by nature, and despite the daunting and doubting times, I much prefer this to being carried with the general flow. I was quite confident in the basic validity of MOND from the very start, which helped me a lot in taking all this in stride, but there are two great advantages to the lingering opposition to MOND: Firstly, it gave me time to make more contributions to MOND than I would had the community jumped on the MOND wagon early on. Secondly, once MOND is accepted, the long and wide resistance to it will only have proven how nontrivial an idea it is.

By the end of my sabbatical in Princeton, I had secretly written three papers introducing MOND to the world. Publishing them, however, was a whole different story. At first I sent my kernel paper to journals such as Nature and Astrophysical Journal Letters, and it got rejected almost off-hand. It took a long time until all three papers were published, side by side, in Astrophysical Journal.

The first person to hear about MOND was my wife Yvonne. Frankly, tears come to my eyes when I say this. Yvonne is not a scientist, but she has been my greatest supporter.

The first scientist to back MOND was another physics maverick: The late Professor Jacob Bekenstein, who was the first to suggest that black holes should have a well-defined entropy, later dubbed the Bekenstein-Hawking entropy. After I submitted the initial MOND trilogy, I sent the preprints to several astrophysicists, but Jacob was the first scientist I discussed MOND with. He was enthusiastic and encouraging from the very start.

Slowly but surely, this tiny opposition to dark matter grew from just two physicists to several hundred proponents, or at least scientists who take MOND seriously. Dark matter is still the scientific consensus, but MOND is now a formidable opponent that proclaims the emperor has no clothes, that dark matter is our generation’s ether.

So what happened? As far as dark matter is concerned, nothing really. A host of experiments searching for dark matter, including the Large Hadron Collider, many underground experiments and several space missions, have failed to directly observe its very existence. Meanwhile, MOND was able to accurately predict the rotation of more and more spiral galaxies—over 150 galaxies to date, to be precise.

All of them? Some papers claim that MOND wasn’t able to predict the dynamics of certain galaxies.

That’s true and it’s perfectly fine, because MOND’s predictions are based on measurements. Given the distribution of regular, visible matter alone, MOND can predict the dynamics of galaxies. But that prediction is based on our initial measurements. We measure the light coming in from a galaxy to calculate its mass, but we often don’t know the distance to that galaxy for sure, so we don’t know for certain just how massive that galaxy really is. And there are other variables, such as molecular gas, that we can’t observe at all. So yes, some galaxies don’t perfectly match MOND’s predictions, but all in all, it’s almost a miracle that we have enough data on galaxies to prove MOND right, over and over again.

Your opponents say MOND’s greatest flaw is its incompatibility with relativistic physics.

In 2004, Bekenstein proposed his TeVeS, or Relativistic Gravitational Theory for MOND. Since then, several different relativistic MOND formulations have been put forth, including one by me, called Bimetric MOND, or BIMOND.

So, no, incorporating MOND into Einsteinian physics is no longer a challenge. I hear this statement still made, but only from people who parrot others, who themselves are not abreast with the developments of the last 10 years. There are several relativistic versions of MOND. What remains a challenge is demonstrating that MOND can account for the mass anomalies in cosmology.

Another argument that cosmologists often make is that dark matter is needed not just for motion within galaxies, but on even larger scales. What does MOND have to say about that?

According to the Big Bang theory, the universe began as a uniform singularity 13.8 billion years ago. And, just as in galaxies, observations made of the cosmic background radiation from the early universe suggest that the gravity of all the matter in the universe is simply not enough to form the different patterns we currently see, like galaxies and stars, in just 13.8 billion years. Once again, dark matter was called to the rescue: It does not emit radiation, but it does engage visible material with gravitation. And so, starting from the 1980s, the new cosmological dogma was that dark matter constituted a staggering 95 percent of all matter in the universe. That lasted, well, right until the bomb hit us in 1998.

It turned out that the expansion of the universe is accelerating, not decelerating like all of us originally thought. Any form of genuine matter, dark or not, should have slowed down acceleration. And so a whole new type of entity was invented: Dark energy. Now the accepted cosmology is that the universe is made up of 70 percent dark energy, 25 percent dark matter, and 5 percent regular matter.

But dark energy is just a quick fix, the same as dark matter is. And just as in galaxies, you can either invent a whole new type of energy and then spend years trying to understand its properties, or you can try fixing your theory.

Among other things, MOND points to a very deep connection between structure and dynamics in galaxies and cosmology. This is not expected in accepted physics. Galaxies are tiny structures within the grand scale of the universe, and those structures can behave differently without contradicting the current cosmological consensus. However, MOND creates this connection, binding the two.

This connection is surprising: For whatever reason, the MOND constant of a0 is close to the acceleration that characterizes the Universe itself. In fact, MOND’s constant equals the speed of light squared, divided by the radius of universe.

So, indeed, to your question, the conundrum pointed to is valid at present. MOND doesn’t have a sufficient cosmology yet, but we’re working on it. And once we fully understand MOND, I believe we’ll also fully understand the expansion of the universe, and vice versa: A new cosmological theory would explain MOND. Wouldn’t that be amazing?

What do you think about the proposed unified theories of physics, which merge MOND with quantum mechanics?

These all hark back to my 1999 paper on ‘MOND as a vacuum effect’, where it was pointed out that the quantum vacuum in a universe such as ours may produce MOND behavior within galaxies, with the cosmological constant appearing in the guise of the MOND acceleration constant, a0. But I am greatly gratified to see these propositions put forth, especially because they are made by people outside the traditional MOND community. It is very important that researchers from other backgrounds become interested in MOND and bring new ideas to further our understanding of its origin.

And what if you had a unified theory of physics that explains everything? What then?

You know, I’m not a religious person, but I often think about our tiny blue dot, and the painstaking work we physicists do here. Who knows? Perhaps somewhere out there, in one of those galaxies I spent my life researching, there already is a known unified theory of physics, with a variation of MOND built into it. But then I think: So what? We still had fun doing the math. We still had the thrill of trying to wrap our heads around the universe, even if the universe never noticed it at all.

Stem Education Coalition

Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

## From Nautilus: “Dark Matter May Show Quantum Effects on a Galactic Scale”

Nautilus

2.18.17
David “Doddy” Marsh

This weird type of dark matter would also puff up galaxies and make stars age prematurely.

Microwave cavity in the ADMX axion detection experiment at the University of Washington. Credit: ADMX.

An axion is a theoretical particle named after a laundry detergent. As particles go, it is a strange one. Its mass is tiny—somewhere between one trillionth the mass of the proton and one billion-trillion-trillionth. It is so lightweight, in fact, that it doesn’t even behave as a particle, but as a wave that could straddle a galaxy. It is also feeble—its influence extends over an almost absurdly short distance, a millionth of what the Large Hadron Collider is able to discern. These short distances stem from the possible relation between axions and very high energy physics, possibly even quantum gravity.

When I first heard of the axion, I had no idea it would become my life’s work. I was a new grad student looking for a starter project, and I came across a paper with such a peculiar title that I couldn’t help but read it: “String Axiverse.” It was written by a group of people including John March-Russell, a theoretical physicist in my department at Oxford. Speaking to John and cosmologist Pedro Ferreira (who both later became my Ph.D. advisors), I realized that the axion was just what I wanted to work on: a fascinating theoretical construct, but with direct connection to the exciting modern progress in cosmology.

An unknown particle that may exist in profusion: the axion is an ideal candidate for dark matter. But it is a very different beast than we’re used to thinking about, requiring us to go about the search for dark matter in a different way.

The Nobelist Frank Wilczek gave the axion its name because it cleaned up a problem in the Standard Model of particle physics. In the 1970s, he and others puzzled over a mismatch between the two forces that govern atomic nuclei: the strong and weak nuclear forces. The strong force has a symmetry in its workings that the weak lacks, even though, a priori, there is no reason it should. Helen Quinn and Robert Peccei proposed that the force is not innately symmetrical, but develops this symmetry under the action of a new field akin to the Higgs field. The axion particle is a remnant of this field.

To play its role, the axion must be extremely lightweight. For our current theories, that is awkward, because it creates an enormous gulf between this particle and all the others. But the low mass is entirely natural in string theory, our leading candidate for a unified theory of nature. String theory predicts there is not just one type of axion, but there are typically 30 or more different kinds, and it predicts that their masses are spread out over a wide range. Some therefore must be lightweight. String theory is often criticized for not making testable predictions, but that’s not quite right, because the theory does predict axions. Although I wouldn’t claim that discovering lots of axions would be evidence for string theory, I think it is fairly safe to say that, according to almost any theory other than string theory, it would be surprising if we discovered large numbers of them.

______________________________________________________________________
If axion dark matter exists, it is completely invisible to a conventional experiment.
______________________________________________________________________

Axions are like other candidates for dark matter in that they are dark—they have no electric charge and therefore do not emit or absorb light—and interact very weakly with ordinary matter. But there the resemblance stops. Compare it to the most commonly discussed type of dark matter, the WIMP, or weakly interacting massive particle.

It is a so-called thermal relic, which, according to theory, is produced the same way as protons, neutrons, and atomic nuclei: from the collisions between particles in the hot, dense, early universe. Given the amount of missing mass that astronomers infer, this production mechanism for WIMPs sets their mass and interaction strength: 100 times the mass of the proton (hence “massive”) with an interaction strength roughly equal to the weak nuclear force (hence “weakly interacting”). These would be lumbering particles, and that is just what astronomers need to explain the distribution of galaxies. If they exist, we should be able to detect them in particle detectors similar to those we use to detect neutrinos, and we should even be able to produce them ourselves by mimicking those hot, dense conditions in the Large Hadron Collider.

LHC at CERN

Axions, in contrast, have a different origin story. Their production is determined not by the temperature of the plasma in the early universe, but gravitationally, by the expansion of space in the big bang. This production mechanism sets their mass and interaction strength, which are vastly different from those of WIMPs.

Big Bang to today. http://www.sun.org/encyclopedia/a-short-history-of-the-universe

Axions would interact with ordinary matter to a limited degree, but only by a unique set of interactions. For this reason, if axion dark matter exists, it is completely invisible to a conventional experiment such a WIMP detector or even the Large Hadron Collider.

The poster-child axion direct-detection experiment is ADMX, which operates at the University of Washington and relies on a concept invented by Pierre Sikivie in 1983. Though “dark”, axions do interact with electromagnetism in other ways and, in the presence of a magnetic field, can metamorphose into photons or vice versa. ADMX attempts to perform the metamorphosis inside a microwave radio-frequency cavity like those used in radar equipment and microwave relay stations. So far ADMX have observed nothing, but it is sensitive only to axions whose wavelengths are comparable to the size of the cavity, and it has still not completed its full search program. Proposed experiments such as MADMAX and CASPEr would probe a much wider range of wavelengths.

In principle, axions might have shown up in experiments intended for other purposes. With colleagues at the University of Sussex, the Swiss Federal Institute of Technology, and the University of New South Wales, as well as two talented grad students, Nicholas Ayres and Michał Rawlik, I have been digging through the archives of the nEDM experiment, which ran for a number of years at the Institut Laue-Langevin in France and is now at the Paul Scherrer Institute in Switzerland. It has been measuring neutrons, which would oscillate in a particular way if a galactic axion wave happened to pass through it, and we are reanalyzing the data to look for this signal.

______________________________________________________________________________________

In this field, there’s room for young theorists such as me to make headway.
______________________________________________________________________________________

If axions exist, stars would produce them naturally. Some of the photons produced during nuclear fusion in the core could metamorphose into axions, and they would escape the star more readily than photons do. This would drain the star of energy and cause it to age faster. Astronomers have been combing through star clusters for stars that look older than they actually are, and they have found no evidence of extra cooling. This null result sets limits on how strongly axions can interact with the constituents of stars.

With my colleagues Dan Grin and Renée Hložek, I have also been searching for axions in cosmological data. Their wavelike properties might give them away. Over distances smaller than the axion wavelength, multiple axion waves would overlap and interfere with one another, causing them to exert an outward pressure and puff up galaxies. And indeed astronomers do find that galaxies are less clumpy than WIMPs should cause them to be (although there are many possible explanations for this, not just axions). My colleagues and I have been exploring this idea further by combining galaxy data with cosmic microwave background radiation measurements, as well as conducting simulations of galaxy formation with axion dark matter.

Finally, axions would alter what happened during cosmic inflation, the primeval period when the universe was expanding at a breakneck rate. Cosmologists generally think the inflationary process created a torrent of gravitational waves, but if dark matter is made of axions, it would have generated very few. So, the discovery of primordial gravitational waves could be taken as falsification of the axion idea, at least in a wide range of models. (If we ever detected both axion dark matter and these gravitational waves, then something would be wrong with standard inflationary theory.)

Only a small band of devotees have given much thought to axions. That makes it a fun field to be working in. There’s room for young theorists such as me to make headway and feel like we’re adding to the understanding of the community, which is much harder to do in a more mature field such studying WIMPs.

It should be said that there is room in the universe for both axions and WIMPs. Both have a firm grounding in fundamental physics and in cosmology, and both may exist out there. For me, one of the benefits of thinking about axions is that they force to think beyond WIMPs. If all we ever do is study and simulate WIMPs because it is relatively easy, as a community we run the risk of confirmation bias, where WIMPs always come up trumps because they are all we know. Thankfully, that doesn’t seem to be how the field of dark-matter research is going. People are exploring a huge range. Dark matter is out there and discovering it is just a matter of time. When we do discover it, whatever it is, it will revolutionize our ideas of particle physics and cosmology.

Stem Education Coalition

Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

## From Nautilus: “When Einstein Tilted at Windmills”

Nautilus

December 1, 2016
By Amanda Gefter

Illustrations by Jasu Hu

The young physicist’s quest to prove the theories of Ernst Mach.

When they met, Einstein wasn’t Einstein yet. He was just Albert Einstein, a kid, about 17, with a dark cloud of teenage angst and a violin. Michele Besso was older, 23, but a kindred spirit. Growing up in Trieste, Italy he had shown an impressive knack for mathematics, but he was kicked out of high school for insubordination and had to go live with his uncle in Rome.

Einstein could relate. At the Swiss Polytechnic, where he was now a student, his professors resented his intellectual arrogance, and had begun locking him out of the library out of spite.

Their first encounter was on a Saturday night in Zurich, 1896. They were at Selina Caprotti’s house by the lake for one of her music parties. Einstein was handsome—dark hair, moustache, soulful brown eyes. Besso was short with narrow, pointed features and a thick pile of coarse black hair on his head and chin. Einstein had a look of cool detachment. Besso had the look of a nervous mystic. As they chatted, Einstein learned that Besso worked at an electrical machinery factory; Besso learned that Einstein was studying physics. Perhaps they recognized something in each other then: They both wanted to get to the truth of things.

Besso would go on to become a sidekick, of sorts, to Einstein—a sounding board, as Einstein put it, “the best in Europe,” asking the right questions that would inspire Einstein to find the right answers. At times, though, he would seem to be something more—a collaborator, perhaps, making suggestions, working through calculations.

At other times he’d be the perfect fool—a schlemiel, Einstein called him. Like the time Besso was sent on a job to inspect some newly installed power lines on the outskirts of Milan but missed his train and then forgot to go the following day. On the third day he finally made it to his destination, but by that time he’d completely forgotten what he was supposed to be doing there in the first place. He sent a postcard to his boss: “Instructions should be wired.”

If Besso never seemed to know quite what he was doing, it wasn’t for a lack of smarts. “The great strength of Besso resides in his intelligence,” Einstein would write, “which is out of the ordinary, and in his endless devotion to both his moral and professional obligations; his weakness is his truly insufficient spirit of decision. This explains why his successes in life do not match up with his brilliant aptitudes and with his extraordinary scientific and technical knowledge.”

Still other times, Besso would play the role of Einstein’s conscience—urging him to work things out with his future wife, Mileva, or to be a better father to his sons. Besso took care of those sons on Einstein’s behalf when Mileva was sick. “Nobody else is so close to me, nobody knows me so well,” Einstein would write in 1918.

But there was something uncanny about Besso. Over the coming years, he would always show up at exactly the right moment, the perfect deus ex machina, handing Einstein books, innocently offering suggestions, prodding him, goading him, nudging him onto the right path, as if he had a plan. “I … watch my friend Einstein struggle with the great Unknown,” he would write, “the work and torment of a giant, of which I am the witness—a pygmy witness—but a pygmy witness endowed with clairvoyance.”

That Saturday night, though, all of that lay in the future. For now, they became fast friends—best friends, really. They talked for hours on end. For his first act of camaraderie, Besso handed Einstein two books, insisting that he read them. They were the works of Ernst Mach, the final actor in this three-man play.

Perhaps you’ve heard of Ernst Mach. Mach 1, Mach 2, Mach 3, that Mach.

Ernst Mach

His name is a unit of speed, and—despite his beard—a brand of razors. He was a physicist, a physiologist, a philosopher. A little bit of everything, really. You could find the young Mach in the Austrian countryside carefully observing nature—staring at a leaf or a shadow or a cloud with the utmost concentration and scrutiny, then scrutinizing his scrutinizing, noting his every sensory glitch and glimmer, building a taxonomy of tricks that our eyes can play. He collected bugs and butterflies. He tested the reactions of various materials—in trying to see whether camphor would ignite, he burned off his eyelashes and eyebrows. But it was when he was 15 years old that a single moment changed everything.

“On a bright summer day in the open air, the world with my ego suddenly appeared to me as one coherent mass of sensations,” he later wrote. He felt, in that moment, there was no reality sitting “out there,” independent of his sensations, and likewise that there was no self sitting “in here,” independent of its sensations. He grew certain that there could be no real difference between mind and matter, between perceiving subject and perceived object. “This moment was decisive for my whole view,” he wrote.

From that day forward, he vehemently rejected any form of dualism: the idea that the external world was made up of substantial material objects—things—while the mind was made of something else, so that the world we experience in consciousness is a mere copy of an actual world that lies forever hidden from us. Instead he grew convinced that mind and matter were made of the same basic ingredient. It couldn’t be a physical ingredient, he argued, because how would bare matter ever give rise to subjective experience? But it couldn’t be a mental ingredient either, he said, because he was certain that the self was equally an illusion. The only way to unite mind and matter, he decided, was to presume that they were made not of objective atoms, and not of subjective qualia, but of some neutral thing, an “element,” he called it, which in one configuration would behave as material substance and in another as immaterial mentation, though in itself it would be neither and nothing.

“There is no rift between the psychical and the physical, no inside and outside, no “sensation” to which an external “thing,” different from sensation, corresponds,” he wrote. “There is but one kind of elements, out of which this supposed inside and outside are formed—elements which are themselves inside or outside, according to the aspect in which, for the time being, they are viewed.” These elements “form the real, immediate, and ultimate foundation.”

Mach’s view—neutral monism, it would later be called—required that every single aspect of reality, from physical objects to subjective sensations, be purely relational, so that whether something was “mind” or “matter” was determined solely by its relations with other elements and not by anything inherent to itself. It was a radical idea, but it seemed plausible. After all, Mach said, science is based on measurement, but “the concept of measurement is a concept of relation.” What we call length or weight, for instance, is really the relation between an object and a ruler, or an object and a scale.

It dawned on Mach, then, that if we could rewrite science solely in terms of what can measured, then the world could be rendered entirely relational—entirely relative—and the mind and universe could be unified at last. But that was going to require a new kind of physics.

By 1904, Don Quixote had become one of Einstein’s favorite books.

Two years earlier, an unemployed Einstein had put an ad in the newspaper offering physics tutoring for three francs an hour, and a philosophy student named Maurice Solovine had shown up at his door. They started talking about physics and philosophy and didn’t stop; the whole tutoring thing never even came up. Soon Conrad Habicht, a mathematics student, joined the conversation, and the three young bohemians formed something of a book club for highbrowed degenerates. They read works of philosophy and literature and discussed them, sometimes until one in the morning, smoking, eating cheap food, getting rowdy and waking the neighbors. They met several nights a week. In mockery of stuffy academia, they dubbed themselves the Olympia Academy.

Besso was in Trieste working as an engineering consultant, but he came when he could, and as Einstein’s closest friend, he was made an honorary member of the Academy. Under Besso’s influence, the Olympians read and discussed Mach. Eventually Einstein landed a job at the Patent Office in Bern, and in 1904 he got Besso a job in the same office, so they could work side by side. In the evenings, the Academy read Don Quixote. It struck a chord with Einstein—later, when his sister Maja lay dying, he would read it to her. As for the Olympia boys, who can say whether they noticed it then: how Besso had become the Sancho Panza to Einstein’s Quixote. When Solovine and Habicht left, it was just Einstein and Besso, walking home together from the patent office, discussing the nature of space and time and, as always, Mach.

Mach’s plan to unite matter and mind required that every last bit of world be rendered relative, with nothing left over. But there was one stubborn obstacle standing in the way: According to physics, all motion was defined relative to absolute space, but absolute space wasn’t defined relative to anything. It just existed, self-defined, like the basement level of reality—it wouldn’t budge. Mach knew of this obstacle, and it rankled. He criticized Newton’s “conceptual monstrosity of absolute space”—the idea of space as a thing unto itself. But how to get around it?

For years it had been bugging Einstein that all attempts on an observer’s part to determine whether or not he was at rest relative to absolute space were doomed to fail. For every experiment he could think of, nature seemed to have a clever trick up its sleeve to hide any evidence of absolute motion. It was so downright conspiratorial that one might suspect, as Einstein did, that absolute space simply didn’t exist.

Following Mach’s lead, Einstein wanted to assert that motion was not defined by reference to absolute space, but only relative to other motion. Unfortunately, the laws of physics seemed to suggest otherwise. The laws of electromagnetism, in particular, insisted that light had to travel at 186,000 miles per second regardless of the observer’s frame of reference. But if all motion was relative, the light’s motion would have to be relative too—traveling 186,000 miles per second in one reference frame and some other speed in another, in blatant violation of electromagnetic law.

So Einstein went to see Besso. “Today I come here to battle against that problem with you,” he announced when he arrived.

They discussed the situation from every angle. Einstein was ready to give up, but they hammered away.

The next day, Einstein returned. “Thank you,” he said. “I’ve completely solved the problem.” Within five weeks, his Theory of Special Relativity was complete.

What magic words had Besso uttered in that fateful conversation? It seems he reminded Einstein of Mach’s central idea: a measurement is always a relation.

Einstein and Besso discussed this—what two quantities we compare in order to measure time. “All our judgments in which time plays a part are always judgments of simultaneous events,” Einstein realized. “If, for instance, I say, ‘That train arrives here at 7 o’clock,’ I mean something like this: ‘The pointing of the small hand of my watch to 7 and the arrival of the train are simultaneous events.”

But how does one know that two events are simultaneous? Perhaps you’re standing still and you see two distant lights flash at precisely the same moment. They’re simultaneous. But what if you had been moving? If you happened to be moving in the direction of flash A and away from flash B, you’d see A happen first, because B’s light would take ever so slightly longer to reach you.

Simultaneity is not absolute. There’s no single “now” in which all observers live. Time is relative. Space, too.

It all dawned on Einstein then: It was possible for all observers to see light moving at exactly 186,000 miles per second regardless of their own state of motion. The light’s speed is a measure of how much distance it covers in a given amount of time. But time changes depending on your state of motion. So even if you’re moving relative to the light, time itself will slow down precisely long enough for you to measure light’s speed at the very one required by Maxwell’s equations.

Einstein’s 1905 paper On the Electrodynamics of Moving Bodies introduced the world to the theory of relativity, in which time and space can slow and stretch to account for an observer’s relative motions. It included no references whatsoever, but it ended with this final paragraph: “In conclusion I wish to say that in working at the problem here dealt with I have had the loyal assistance of my friend and colleague M. Besso, and that I am indebted to him for several valuable suggestions.”

Einstein proudly sent his work to Mach, and seemed almost giddy when Mach responded with his approval. “Your friendly letter gave me enormous pleasure,” Einstein replied. “I am very glad that you are pleased with the relativity theory … Thanking you again for your friendly letter, I remain, your student, A. Einstein.”

Einstein had a long way to go, however, to see Mach’s vision through. The problem was that special relativity only relativized motion for observers moving at a constant speed. The question of accelerated observers—those who were changing speed or rotating—was far trickier. Within special relativity, there was no way to blame the force that comes with acceleration on relative motion. Absolute space lingered.

In 1907, Einstein made a breakthrough. It was the happiest thought of his life, he would later say: In small regions of space, an observer would be unable to tell whether he was accelerating or at rest in a gravitational field. This suggested that it might be possible to do away with the absolute nature of acceleration—and with it absolute space—once and for all. Gravity, it seemed, was the secret ingredient that made all motion relative, just as Mach had wanted. And that gave a whole new meaning to the very nature of gravity: The path of an accelerated observer through spacetime traces a curve, so if acceleration was equivalent to gravity, then gravity was the curvature of spacetime. It would be some time before Einstein brought his General Theory of Relativity to fruition, but for now, he knew he was on the right track.

Excited, Einstein wrote a letter to Mach informing him of his progress and the publication of his newest paper. A new theory of gravity was underway, he said, and as soon as he could prove it correct, “your inspired investigations into the foundations of mechanics … will receive a splendid confirmation.” In other words: I’ve done what you wanted. He published his theory of general relativity in 1915; the next year, Mach died.

Einstein wrote a long and moving obituary, glowing with praise for Mach’s scientific vision, with its central point, as Einstein wrote, that “physics and psychology are to be distinguished from each other not by the objects they study but only by the manner of ordering and relating them.” He argued that Mach himself was close to coming up with the theory of relativity, and wrote, with palpable admiration and innocence, that Mach “helped me a lot, both directly and indirectly.”

That, however, was the apogee of the kinship between Einstein and Mach’s philosophy. Einstein would eventually disavow the pure relativism of his mentor, and even to split from his Sancho. The rift begins with a most unlikely event: words from beyond the grave.

In 1921, Mach’s book The Principles of Physical Optics was published posthumously, and contained a preface written by the author around 1913, shortly after Einstein had sent him the early paper on general relativity.

“I am compelled in what may be my last opportunity, to cancel my views of the relativity theory,” Mach wrote. “I gather from the publications which have reached me, and especially from my correspondence, that I am gradually becoming regarded as the forerunner of relativity … I must as assuredly disclaim to be a forerunner of the relativists …”

Mach had likely seen what Einstein would only later come to terms with—that the so-called general theory of relativity did not live up to its name. General relativity was an unprecedented intellectual feat—but it didn’t make everything relative, as Mach had dreamed. In the final version of the theory, the equivalence between acceleration and gravitation, which had seemed to make all motion relative, turned out to hold only for infinitesimally small regions of space. Patching together local regions into one big universe produced misalignments at their edges, like flat tiles on a round globe. The misalignments revealed the curvature of spacetime—a global geometry that couldn’t be transformed away by a mere change in perspective. Each local region—a self-consistent, relative world—turned out to be the tiny tip of an enormous, four-dimensional iceberg, forever hidden from sight and decidedly not relative.

It must have been an unsettling feeling for Einstein—watching his theory gather steam and speed away from him, proving the very thing he had set out to disprove. The problem was that, according to the theory, spacetime geometry was not fully determined by the distribution of matter in the universe, so that even if you removed everything observable, some extra ingredient still remained—spacetime itself, dynamic yet absolute. It created an unbridgeable divide between the physical world and the mind, inviting, in its realist stance, a whiff of pure belief, even mysticism—the belief in a four-dimensional substratum, the paper on which reality is drawn, though the paper itself is invisible.

Einstein continued to push Mach’s view for several years after publishing general relativity in 1915, living in total denial of the fact that his own theory went against it. He tried everything under the sun to mold his theory into the shape of Mach’s philosophy—making the universe finite but unbounded, adding a cosmological constant—but it just wouldn’t fit. “The necessity to uphold [Mach’s principle] is by no means shared by all colleagues,” he said, “but I myself feel it is absolutely necessary to satisfy it.”

So when Einstein first read Mach’s preface, it must have stung. We can hear his hurt in a comment he made at a lecture in Paris in 1922, shortly after Mach’s preface was published. Mach was un bon mecanicien, Einstein said bitterly, but a “deplorable philosophe.” He would no longer claim that his theory was one of Machian relativism, and by 1931 he would abandon Mach’s views completely. “The belief in an external world independent of the perceiving subject is the basis of all natural science,” he wrote. When asked how he could believe in anything beyond our sensory experience, he replied: “I cannot prove my conception is right, but that is my religion.” And in 1954, a year before his death: “We ought not to speak about the Machian Principle anymore.”

What Mach had never known—couldn’t have known—was that his true devotee had never been Einstein. It was Besso.

Besso, that pygmy witness endowed with clairvoyance, saw exactly where Einstein’s departure from Mach would soon lead him astray: in the realm of quantum mechanics.

As Einstein came to grips with Mach’s rejection of relativity, the world of physics was rocked by quantum theory, a revolution Einstein had helped to spark but now refused to join. While he was making peace with an absolute spacetime—an absolute reality—quantum mechanics was rendering the world even more relative. The theory suggested that the outcomes of measurements could be defined only in relation to a given experiment: An electron might be a wave relative to one measuring apparatus and a particle relative to another, though in itself it was neither and nothing. In the words of Niels Bohr, the purpose of the theory was “to track down, so far as it is possible, relations between the manifold aspects of our experience”—relations and nothing more. In other words, quantum theory picked up Mach’s program right where Einstein left off, a point that both Bohr and Besso were quick to emphasize.

When Einstein, complaining about a colleague’s work, joked to Besso that, “He rides Mach’s poor horse to exhaustion,” Besso replied, “As to Mach’s little horse, we should not insult it; did it not make possible the infernal journey through the relativities? And who knows—in the case of the nasty quanta, it may also carry Don Quixote de la Einsta through it all!”

“I do not inveigh against Mach’s little horse,” Einstein responded, “but you know what I think about it. It cannot give birth to anything living.”

The truth was, Einstein’s belief in a hidden reality had lain dormant for years, ever since he was a little boy—4, maybe 5—and his father had come to his bedside and handed him a compass. Einstein had held it in his hand, and found himself trembling in awe. The way the needle quivered, tugged northward by some invisible force, overwhelmed him with the feeling that “something deeply hidden had to be behind things.” Now he glimpsed it again in the mathematics of general relativity. With Mach’s approval moot, the awe he’d felt as a boy returned to him. When Besso tried to steer him away—toward Mach, toward the quantum— Einstein reproached his faithful squire: “It appears that you do not take the four-dimensionality of reality seriously.”

The reinvention of Einstein as a young iconoclast who embraced Mach’s view and ran with it, determined to create a theory of pure relativity despite his natural realist leanings—was it actually Besso’s doing? Had the squire steered his master? In the short story “The Truth About Sancho Panza,” Franz Kafka suggests that this reversal is, in fact, the key to Cervantes’ tale. Don Quixote, he wrote, was Sancho Panza’s own creation, an alter ego invented to carry out some inner vision Panza himself was ill equipped to face. “I owe to you the scientific synthesis that without such a friendship one would never have acquired—at least, not without expending all one’s personal forces,” Besso wrote to Einstein—as if to say, thanks for working out that theory for me. But the synthesis was incomplete. Having guided Einstein to water, Besso appears to have failed to make him drink.

Besso never gave up on luring Einstein back to Machian relativity. But Don Quixote had abandoned the knighthood for good, leaving Sancho to fend off the windmills for himself. In Princeton, New Jersey, his hair now white and wild, Einstein sat at a cluttered desk and struggled with reality while physics marched on without him. In Geneva, Switzerland, in the University mathematics library, his wiry beard now blanched with time, Besso sat hunched over his own pile of books, and worked—quietly, mysteriously—alone.

Stem Education Coalition

Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r