Tagged: Lawrence Krauss Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 12:37 pm on October 27, 2017 Permalink | Reply
    Tags: , Is he feeling optimistic about the world right now?, Lawrence Krauss, Lawrence Krauss eyes the clock   

    From COSMOS: “Lawrence Krauss eyes the clock” 

    Cosmos Magazine bloc

    COSMOS Magazine

    27 October 2017
    Andrew Masterson

    1
    Cosmologist Lawrence Krauss: pessimistic, but not gloomy. Brian de Rivera Simon/WireImage

    [Krauss said once that all scientists should be militant atheists. I object always to militancy of any kind. Beyond that people are free to choose as they wish.]

    A few days from now, theoretical physicist, cosmologist and author Lawrence Krauss will meet with other distinguished scientists to decide the next move in a project that was started just after World War II by Albert Einstein and Robert Oppenheimer.

    In his day job Krauss is the Foundation Professor of the School of Earth and Space Exploration at Arizona State University in the US, but in his downtime he also heads up the board of sponsors for the Bulletin of Atomic Scientists.

    In January every year the Bulletin folk garner a hefty burst of media coverage, because the organisation maintains the well-known Doomsday Clock: the visual and symbolic measure of how close the Earth is to the point of total environmental disaster.

    This year, citing among other matters new US president Donald Trump’s active antipathy to climate change mitigation and nuclear weapons abolition, the boffins twitched the big hand forward. It now sits at two-and-half-minutes to midnight.

    Very soon, the Bulletin must decide what do next time. Krauss has already made his mind up, but isn’t in a sharing mood.

    “If I told you I’d have to kill you,” he laughs.

    (And then, by the way, he eats a Halloween-themed candy that looks like a brain. It is faintly disturbing.)

    The Doomsday Clock’s current position suggests humanity’s prospects are parlous. The simplest explanation for this is to attribute it is to the rise in influence of alt-right anti-science lobbies and the consequent abandonment of evidence as a basis for policy-making.

    Krauss agrees, but finds fault too with himself and fellow scientists, and with everyone who until recently wrote off fundamentalist religion and climate change denial as products of fringe communities.

    “We were complacent, for sure,” he says.

    “I don’t think they were so much on the fringe. They are not on the fringe. I wish they had been. People have been intimidated. Now we’re in a position where government leaders are obviously anti-science and in many cases religious fundamentalists.

    “And that’s a huge problem because they are making policies that are clearly ridiculous. That’s a new concern, but there’s always been another one, which is more pervasive.

    “There are people, millions of them, who feel they are bad people because they question the existence of god.”

    In the US, he explains, agnosticism, much less atheism, is rarely discussed. Those who question the existence of deities often, thus, feel isolated, alone and damaged.

    This needs to change, he says. The godless need to get together and get loud.

    “What we haven’t done enough of is encourage more people to openly ridicule stupid ideas,” he says.

    “Or at least encourage people to ask questions. I think we’ve been far too polite and far too lenient – at least in my country – on religious fundamentalism.”

    That, however, needs to be but one prong of a two-pronged assault.

    “We also have not done a good job of teaching science,” he continues. “These are intimately related, because how do you tell the difference between sense and nonsense in this modern political arena filled with ‘alternative facts’?

    “We have this problem, and I really do think it stems from teaching science the wrong way. We teach it as if it’s a bunch of facts, but it’s not: it’s a process for deriving facts.”

    Over the years, Krauss has made solid contributions not just to his own fields of research but also to the cause of popularising science. His mass market books, such as The Physics of Star Trek in 1995 and A Universe from Nothing in 2012 have been best-sellers.

    Now he has embarked on a new type of teaching journey, teaming up with evolutionary biologist Richard Dawkins in a travelling two-man show called Science In The Soul.

    While neither scientist is a stranger to publicity or controversy, Krauss draws a distinction between the way they approach their tasks.

    “It’s one of the discussions I often have with Richard,” he says,

    “And I think it’s because Richard has lived in [the UK academic city of] Oxford his whole life, or almost.

    “He’s one of the most impatient persons with irrationality that I’ve ever known, whereas I live in the United States so I’m quite used to it.”

    Dawkins and Krauss are bringing their show to Australia in May next year. Tickets are on sale now.

    By then, of course, we and the rest of the world will know whether the Bulletin of Atomic Scientists decided to move the hand of the Doomsday Clock closer to midnight.

    Krauss – being a media pro as much as a scientist – will never be tempted to break embargo and let us know the decision early, but perhaps we can seek a clue obliquely.

    Is he feeling optimistic about the world right now?

    “No,” he answers. “I think that’s the sensible answer. Like my friend [novelist] Cormac McCarthy once said, ‘I’m a pessimist but that’s no reason to be gloomy’.

    “We are living in dangerous times and certainly there are many indicators that suggest that the world is getting more dangerous against various existential threats.

    “So I’m not optimistic at this point, but that doesn’t mean we give up hope, and that doesn’t mean we give up acting. And part of the point of the Bulletin is to speak out and get people to act.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
    • stewarthoughblog 10:43 pm on October 27, 2017 Permalink | Reply

      Krauss is becoming more irrational, bigoted and biased with each of his anti-intellectual surges. His none book is duplicitous usurpation of science and knowledge to suit his own ideological mandates.

      Like

    • richardmitnick 7:55 am on October 28, 2017 Permalink | Reply

      I only approved your comment for freedom o speech. I agree, on atheism, Krauss is a demigod. But he is entitled to his own opinions. He should keep them to himself. Yet, in Astronomy and Cosmology he is a rock star. I keep all non-science issues out of my blog.

      Like

  • richardmitnick 12:52 pm on March 16, 2017 Permalink | Reply
    Tags: , Lawrence Krauss, Nauilus, , , , Supersymetry   

    From Nautilus: “A Brief History of the Grand Unified Theory of Physics” 

    Nautilus

    Nautilus

    March 16, 2017
    Lawrence M. Krauss
    Paintings by Jonathan Feldschuh

    Particle physicists had two nightmares before the Higgs particle was discovered in 2012. The first was that the Large Hadron Collider (LHC) particle accelerator would see precisely nothing.


    CERN ATLAS Higgs Event

    CERN ATLAS detector


    CERN CMS Higgs Event


    CERN CMS detector




    LHC at CERN

    For if it did, it would likely be the last large accelerator ever built to probe the fundamental makeup of the cosmos. The second was that the LHC would discover the Higgs particle predicted by theoretical physicist Peter Higgs in 1964 … and nothing else.

    Each time we peel back one layer of reality, other layers beckon. So each important new development in science generally leaves us with more questions than answers. But it also usually leaves us with at least the outline of a road map to help us begin to seek answers to those questions. The successful discovery of the Higgs particle, and with it the validation of the existence of an invisible background Higgs field throughout space (in the quantum world, every particle like the Higgs is associated with a field), was a profound validation of the bold scientific developments of the 20th century.

    2
    Particles #22

    However, the words of Sheldon Glashow continue to ring true: The Higgs is like a toilet. It hides all the messy details we would rather not speak of. The Higgs field interacts with most elementary particles as they travel through space, producing a resistive force that slows their motion and makes them appear massive. Thus, the masses of elementary particles that we measure, and that make the world of our experience possible is something of an illusion—an accident of our particular experience.

    As elegant as this idea might be, it is essentially an ad hoc addition to the Standard Model of physics—which explains three of the four known forces of nature, and how these forces interact with matter.


    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    It is added to the theory to do what is required to accurately model the world of our experience. But it is not required by the theory. The universe could have happily existed with massless particles and a long-range weak force (which, along with the strong force, gravity, and electromagnetism, make up the four known forces). We would just not be here to ask about them. Moreover, the detailed physics of the Higgs is undetermined within the Standard Model alone. The Higgs could have been 20 times heavier, or 100 times lighter.

    Why, then, does the Higgs exist at all? And why does it have the mass it does? (Recognizing that whenever scientists ask “Why?” we really mean “How?”) If the Higgs did not exist, the world we see would not exist, but surely that is not an explanation. Or is it? Ultimately to understand the underlying physics behind the Higgs is to understand how we came to exist. When we ask, “Why are we here?,” at a fundamental level we may as well be asking, “Why is the Higgs here?” And the Standard Model gives no answer to this question.

    Some hints do exist, however, coming from a combination of theory and experiment. Shortly after the fundamental structure of the Standard Model became firmly established, in 1974, and well before the details were experimentally verified over the next decade, two different groups of physicists at Harvard, where both Sheldown Glashow and Steven Weinberg were working, noticed something interesting. Glashow, along with Howard Georgi, did what Glashow did best: They looked for patterns among the existing particles and forces and sought out new possibilities using the mathematics of group theory.

    In the Standard Model the weak and electromagnetic forces of nature are unified at a high-energy scale, into a single force that physicists call the “electroweak force.” This means that the mathematics governing the weak and electromagnetic forces are the same, both constrained by the same mathematical symmetry, and the two forces are different reflections of a single underlying theory. But the symmetry is “spontaneously broken” by the Higgs field, which interacts with the particles that convey the weak force, but not the particles that convey the electromagnetic force. This accident of nature causes these two forces to appear as two separate and distinct forces at scales we can measure—with the weak force being short-range and electromagnetism remaining long-range.

    Georgi and Glashow tried to extend this idea to include the strong force, and discovered that all of the known particles and the three non-gravitational forces could naturally fit within a single fundamental symmetry structure. They then speculated that this symmetry could spontaneously break at some ultrahigh energy scale (and short distance scale) far beyond the range of current experiments, leaving two separate and distinct unbroken symmetries left over—resulting in separate strong and electroweak forces. Subsequently, at a lower energy and larger distance scale, the electroweak symmetry would break, separating the electroweak force into the short-range weak and the long-range electromagnetic force.

    They called such a theory, modestly, a Grand Unified Theory (GUT).

    At around the same time, Weinberg and Georgi along with Helen Quinn noticed something interesting—following the work of Frank Wilczek, David Gross, and David Politzer. While the strong interaction got weaker at smaller distance scales, the electromagnetic and weak interactions got stronger.

    It didn’t take a rocket scientist to wonder whether the strength of the three different interactions might become identical at some small-distance scale. When they did the calculations, they found (with the accuracy with which the interactions were then measured) that such a unification looked possible, but only if the scale of unification was about 15 orders of magnitude in scale smaller than the size of the proton.

    This was good news if the unified theory was the one proposed by Howard Georgi and Glashow—because if all the particles we observe in nature got unified this way, then new particles (called gauge bosons) would exist that produce transitions between quarks (which make up protons and neutrons), and electrons and neutrinos. That would mean protons could decay into other lighter particles, which we could potentially observe. As Glashow put it, “Diamonds aren’t forever.”

    Even then it was known that protons must have an incredibly long lifetime. Not just because we still exist almost 14 billion years after the big bang, but because we all don’t die of cancer as children. If protons decayed with an average lifetime smaller than about a billion billion years, then enough protons would decay in our bodies during our childhood to produce enough radiation to kill us. Remember that in quantum mechanics, processes are probabilistic. If an average proton lives a billion billion years, and if one has a billion billion protons, then on average one will decay each year. There are a lot more than a billion billion protons in our bodies.

    However, with the incredibly small proposed distance scale and therefore the incredibly large mass scale associated with spontaneous symmetry breaking in Grand Unification, the new gauge bosons would get large masses. That would make the interactions they mediate be so short-range that they would be unbelievably weak on the scale of protons and neutrons today. As a result, while protons could decay, they might live, in this scenario, perhaps a million billion billion billion years before decaying. Still time to hold onto your growth stocks.

    With the results of Glashow and Georgi, and Georgi, Quinn, and Weinberg, the smell of grand synthesis was in the air. After the success of the electroweak theory, particle physicists were feeling ambitious and ready for further unification.

    How would one know if these ideas were correct, however? There was no way to build an accelerator to probe an energy scale a million billion times greater than the rest mass energy of protons. Such a machine would have to have a circumference of the moon’s orbit. Even if it was possible, considering the earlier debacle over the Superconducting Super Collider, no government would ever foot the bill.


    Superconducting Super Collider map, in the vicinity of Waxahachie, Texas.

    Happily, there was another way, using the kind of probability arguments I just presented that give limits to the proton lifetime. If the new Grand Unified Theory predicted a proton lifetime of, say, a thousand billion billion billion years, then if one could put a thousand billion billion billion protons in a single detector, on average one of them would decay each year.

    Where could one find so many protons? Simple: in about 3,000 tons of water.

    So all that was required was to get a tank of water, put it in the dark, make sure there were no radioactivity backgrounds, surround it with sensitive phototubes that can detect flashes of light in the detector, and then wait for a year to see a burst of light when a proton decayed. As daunting as this may seem, at least two large experiments were commissioned and built to do just this, one deep underground next to Lake Erie in a salt mine, and one in a mine near Kamioka, Japan. The mines were necessary to screen out incoming cosmic rays that would otherwise produce a background that would swamp any proton decay signal.

    Both experiments began taking data around 1982–83. Grand Unification seemed so compelling that the physics community was confident a signal would soon appear and Grand Unification would mean the culmination of a decade of amazing change and discovery in particle physics—not to mention another Nobel Prize for Glashow and maybe some others.

    Unfortunately, nature was not so kind in this instance. No signals were seen in the first year, the second, or the third. The simplest elegant model proposed by Glashow and Georgi was soon ruled out. But once the Grand Unification bug had caught on, it was not easy to let it go. Other proposals were made for unified theories that might cause proton decay to be suppressed beyond the limits of the ongoing experiments.

    On Feb. 23, 1987, however, another event occurred that demonstrates a maxim I have found is almost universal: Every time we open a new window on the universe, we are surprised. On that day a group of astronomers observed, in photographic plates obtained during the night, the closest exploding star (a supernova) seen in almost 400 years.

    3
    NASA is celebrating the 30th anniversary of SN 1987A by releasing new data.

    The star, about 160,000 light-years away, was in the Large Magellanic Cloud—a small satellite galaxy of the Milky Way observable in the southern hemisphere.


    Large Magellanic Cloud. Adrian Pingstone December 2003

    If our ideas about exploding stars are correct, most of the energy released should be in the form of neutrinos, despite that the visible light released is so great that supernovas are the brightest cosmic fireworks in the sky when they explode (at a rate of about one explosion per 100 years per galaxy). Rough estimates then suggested that the huge IMB (Irvine- Michigan-Brookhaven) and Kamiokande water detectors should see about 20 neutrino events.

    5
    Irvine- Michigan-Brookhaven detector


    Super Kamiokande detector

    When the IMB and Kamiokande experimentalists went back and reviewed their data for that day, lo and behold IMB displayed eight candidate events in a 10-second interval, and Kamiokande displayed 11 such events. In the world of neutrino physics, this was a flood of data. The field of neutrino astrophysics had suddenly reached maturity. These 19 events produced perhaps 1,900 papers by physicists, such as me, who realized that they provided an unprecedented window into the core of an exploding star, and a laboratory not just for astrophysics but also for the physics of neutrinos themselves.

    Spurred on by the realization that large proton-decay detectors might serve a dual purpose as new astrophysical neutrino detectors, several groups began to build a new generation of such dual-purpose detectors. The largest one in the world was again built in the Kamioka mine and was called Super-Kamiokande, and with good reason. This mammoth 50,000-ton tank of water, surrounded by 11,800 phototubes, was operated in a working mine, yet the experiment was maintained with the purity of a laboratory clean room. This was absolutely necessary because in a detector of this size one had to worry not only about external cosmic rays, but also about internal radioactive contaminants in the water that could swamp any signals being searched for.

    Meanwhile, interest in a related astrophysical neutrino signature also reached a new high during this period. The sun produces neutrinos due to the nuclear reactions in its core that power it, and over 20 years, using a huge underground detector, physicist Ray Davis had detected solar neutrinos, but had consistently found an event rate about a factor of three below what was predicted using the best models of the sun. A new type of solar neutrino detector was built inside a deep mine in Sudbury, Canada, which became known as the Sudbury Neutrino Observatory (SNO).


    SNOLAB, Sudbury, Ontario, Canada.

    Super-Kamiokande has now been operating almost continuously, through various upgrades, for more than 20 years. No proton-decay signals have been seen, and no new supernovas observed. However, the precision observations of neutrinos at this huge detector, combined with complementary observations at SNO, definitely established that the solar neutrino deficit observed by Ray Davis is real, and moreover that it is not due to astrophysical effects in the sun but rather due to the properties of neutrinos. The implication was that at least one of the three known types of neutrinos is not massless. Since the Standard Model does not accommodate neutrinos’ masses, this was the first definitive observation that some new physics, beyond the Standard Model and beyond the Higgs, must be operating in nature.

    Soon after this, observations of higher-energy neutrinos that regularly bombard Earth as high-energy cosmic-ray protons hit the atmosphere and produce a downward shower of particles, including neutrinos, demonstrated that yet a second neutrino has mass. This mass is somewhat larger, but still far smaller than the mass of the electron. For these results team leaders at SNO and Kamiokande were awarded the 2015 Nobel Prize in Physics—a week before I wrote the first draft of these words. To date these tantalizing hints of new physics are not explained by current theories.

    The absence of proton decay, while disappointing, turned out to be not totally unexpected. Since Grand Unification was first proposed, the physics landscape had shifted slightly. More precise measurements of the actual strengths of the three non-gravitational interactions—combined with more sophisticated calculations of the change in the strength of these interactions with distance—demonstrated that if the particles of the Standard Model are the only ones existing in nature, the strength of the three forces will not unify at a single scale. In order for Grand Unification to take place, some new physics at energy scales beyond those that have been observed thus far must exist. The presence of new particles would not only change the energy scale at which the three known interactions might unify, it would also tend to drive up the Grand Unification scale and thus suppress the rate of proton decay—leading to predicted lifetimes in excess of a million billion billion billion years.

    As these developments were taking place, theorists were driven by new mathematical tools to explore a possible new type of symmetry in nature, which became known as supersymmetry.


    Standard model of Supersymmetry DESY

    This fundamental symmetry is different from any previous known symmetry, in that it connects the two different types of particles in nature, fermions (particles with half-integer spins) and bosons (particles with integer spins). The upshot of this is that if this symmetry exists in nature, then for every known particle in the Standard Model at least one corresponding new elementary particle must exist. For every known boson there must exist a new fermion. For every known fermion there must exist a new boson.

    Since we haven’t seen these particles, this symmetry cannot be manifest in the world at the level we experience it, and it must be broken, meaning the new particles will all get masses that could be heavy enough so that they haven’t been seen in any accelerator constructed thus far.

    What could be so attractive about a symmetry that suddenly doubles all the particles in nature without any evidence of any of the new particles? In large part the seduction lay in the very fact of Grand Unification. Because if a Grand Unified theory exists at a mass scale of 15 to 16 orders of magnitude higher energy than the rest mass of the proton, this is also about 13 orders of magnitude higher than the scale of electroweak symmetry breaking. The big question is why and how such a huge difference in scales can exist for the fundamental laws of nature. In particular, if the Standard Model Higgs is the true last remnant of the Standard Model, then the question arises, Why is the energy scale of Higgs symmetry breaking 13 orders of magnitude smaller than the scale of symmetry breaking associated with whatever new field must be introduced to break the GUT symmetry into its separate component forces?

    ____________________________________________________________________________
    Following three years of LHC runs, there are no signs of supersymmetry whatsoever.
    ____________________________________________________________________________

    The problem is a little more severe than it appears. When one considers the effects of virtual particles (which appear and disappear on timescales so short that their existence can only be probed indirectly), including particles of arbitrarily large mass, such as the gauge particles of a presumed Grand Unified Theory, these tend to drive up the mass and symmetry-breaking scale of the Higgs so that it essentially becomes close to, or identical to, the heavy GUT scale. This generates a problem that has become known as the naturalness problem. It is technically unnatural to have a huge hierarchy between the scale at which the electroweak symmetry is broken by the Higgs particle and the scale at which the GUT symmetry is broken by whatever new heavy field scalar breaks that symmetry.

    The mathematical physicist Edward Witten argued in an influential paper in 1981 that supersymmetry had a special property. It could tame the effect that virtual particles of arbitrarily high mass and energy have on the properties of the world at the scales we can currently probe. Because virtual fermions and virtual bosons of the same mass produce quantum corrections that are identical except for a sign, if every boson is accompanied by a fermion of equal mass, then the quantum effects of the virtual particles will cancel out. This means that the effects of virtual particles of arbitrarily high mass and energy on the physical properties of the universe on scales we can measure would now be completely removed.

    If, however, supersymmetry is itself broken (as it must be or all the supersymmetric partners of ordinary matter would have the same mass as the observed particles and we would have observed them), then the quantum corrections will not quite cancel out. Instead they would yield contributions to masses that are the same order as the supersymmetry-breaking scale. If it was comparable to the scale of the electroweak symmetry breaking, then it would explain why the Higgs mass scale is what it is.

    And it also means we should expect to begin to observe a lot of new particles—the supersymmetric partners of ordinary matter—at the scale currently being probed at the LHC.

    This would solve the naturalness problem because it would protect the Higgs boson masses from possible quantum corrections that could drive them up to be as large as the energy scale associated with Grand Unification. Supersymmetry could allow a “natural” large hierarchy in energy (and mass) separating the electroweak scale from the Grand Unified scale.

    That supersymmetry could in principle solve the hierarchy problem, as it has become known, greatly increased its stock with physicists. It caused theorists to begin to explore realistic models that incorporated supersymmetry breaking and to explore the other physical consequences of this idea. When they did so, the stock price of supersymmetry went through the roof. For if one included the possibility of spontaneously broken supersymmetry into calculations of how the three non-gravitational forces change with distance, then suddenly the strength of the three forces would naturally converge at a single, very small-distance scale. Grand Unification became viable again!

    Models in which supersymmetry is broken have another attractive feature. It was pointed out, well before the top quark was discovered, that if the top quark was heavy, then through its interactions with other supersymmetric partners, it could produce quantum corrections to the Higgs particle properties that would cause the Higgs field to form a coherent background field throughout space at its currently measured energy scale if Grand Unification occurred at a much higher, superheavy scale. In short, the energy scale of electroweak symmetry breaking could be generated naturally within a theory in which Grand Unification occurs at a much higher energy scale. When the top quark was discovered and indeed was heavy, this added to the attractiveness of the possibility that supersymmetry breaking might be responsible for the observed energy scale of the weak interaction.

    _____________________________________________________________________
    In order for Grand Unification to take place, some new physics at energy scales beyond those that have been observed thus far must exist.
    _____________________________________________________________________

    All of this comes at a cost, however. For the theory to work, there must be two Higgs bosons, not just one. Moreover, one would expect to begin to see the new supersymmetric particles if one built an accelerator such as the LHC, which could probe for new physics near the electroweak scale. Finally, in what looked for a while like a rather damning constraint, the lightest Higgs in the theory could not be too heavy or the mechanism wouldn’t work.

    As searches for the Higgs continued without yielding any results, accelerators began to push closer and closer to the theoretical upper limit on the mass of the lightest Higgs boson in supersymmetric theories. The value was something like 135 times the mass of the proton, with details to some extent depending on the model. If the Higgs could have been ruled out up to that scale, it would have suggested all the hype about supersymmetry was just that.

    Well, things turned out differently. The Higgs that was observed at the LHC has a mass about 125 times the mass of the proton. Perhaps a grand synthesis was within reach.

    The answer at present is … not so clear. The signatures of new super- symmetric partners of ordinary particles should be so striking at the LHC, if they exist, that many of us thought that the LHC had a much greater chance of discovering supersymmetry than it did of discovering the Higgs. It didn’t turn out that way. Following three years of LHC runs, there are no signs of supersymmetry whatsoever. The situation is already beginning to look uncomfortable. The lower limits that can now be placed on the masses of supersymmetric partners of ordinary matter are getting higher. If they get too high, then the supersymmetry-breaking scale would no longer be close to the electroweak scale, and many of the attractive features of supersymmetry breaking for resolving the hierarchy problem would go away.

    But the situation is not yet hopeless, and the LHC has been turned on again, this time at higher energy. It could be that supersymmetric particles will soon be discovered.

    If they are, this will have another important consequence. One of the bigger mysteries in cosmology is the nature of the dark matter that appears to dominate the mass of all galaxies we can see.


    Dark matter cosmic web and the large-scale structure it forms The Millenium Simulation, V. Springel et al

    There is so much of it that it cannot be made of the same particles as normal matter. If it were, for example, the predictions of the abundance of light elements such as helium produced in the big bang would no longer agree with observation. Thus physicists are reasonably certain that the dark matter is made of a new type of elementary particle. But what type?

    Well, the lightest supersymmetric partner of ordinary matter is, in most models, absolutely stable and has many of the properties of neutrinos. It would be weakly interacting and electrically neutral, so that it wouldn’t absorb or emit light. Moreover, calculations that I and others performed more than 30 years ago showed that the remnant abundance today of the lightest supersymmetric particle left over after the big bang would naturally be in the range so that it could be the dark matter dominating the mass of galaxies.

    In that case our galaxy would have a halo of dark matter particles whizzing throughout it, including through the room in which you are reading this. As a number of us also realized some time ago, this means that if one designs sensitive detectors and puts them underground, not unlike, at least in spirit, the neutrino detectors that already exist underground, one might directly detect these dark matter particles. Around the world a half dozen beautiful experiments are now going on to do just that. So far nothing has been seen, however.

    So, we are in potentially the best of times or the worst of times. A race is going on between the detectors at the LHC and the underground direct dark matter detectors to see who might discover the nature of dark matter first. If either group reports a detection, it will herald the opening up of a whole new world of discovery, leading potentially to an understanding of Grand Unification itself. And if no discovery is made in the coming years, we might rule out the notion of a simple supersymmetric origin of dark matter—and in turn rule out the whole notion of supersymmetry as a solution of the hierarchy problem. In that case we would have to go back to the drawing board, except if we don’t see any new signals at the LHC, we will have little guidance about which direction to head in order to derive a model of nature that might actually be correct.

    Things got more interesting when the LHC reported a tantalizing possible signal due to a new particle about six times heavier than the Higgs particle. This particle did not have the characteristics one would expect for any supersymmetric partner of ordinary matter. In general the most exciting spurious hints of signals go away when more data are amassed, and about six months after this signal first appeared, after more data were amassed, it disappeared. If it had not, it could have changed everything about the way we think about Grand Unified Theories and electroweak symmetry, suggesting instead a new fundamental force and a new set of particles that feel this force. But while it generated many hopeful theoretical papers, nature seems to have chosen otherwise.

    The absence of clear experimental direction or confirmation of super- symmetry has thus far not bothered one group of theoretical physicists. The beautiful mathematical aspects of supersymmetry encouraged, in 1984, the resurrection of an idea that had been dormant since the 1960s when Yoichiro Nambu and others tried to understand the strong force as if it were a theory of quarks connected by string-like excitations. When supersymmetry was incorporated in a quantum theory of strings, to create what became known as superstring theory, some amazingly beautiful mathematical results began to emerge, including the possibility of unifying not just the three non-gravitational forces, but all four known forces in nature into a single consistent quantum field theory.

    However, the theory requires a host of new spacetime dimensions to exist, none of which has been, as yet, observed. Also, the theory makes no other predictions that are yet testable with currently conceived experiments. And the theory has recently gotten a lot more complicated so that it now seems that strings themselves are probably not even the central dynamical variables in the theory.

    None of this dampened the enthusiasm of a hard core of dedicated and highly talented physicists who have continued to work on superstring theory, now called M-theory, over the 30 years since its heyday in the mid-1980s. Great successes are periodically claimed, but so far M-theory lacks the key element that makes the Standard Model such a triumph of the scientific enterprise: the ability to make contact with the world we can measure, resolve otherwise inexplicable puzzles, and provide fundamental explanations of how our world has arisen as it has. This doesn’t mean M-theory isn’t right, but at this point it is mostly speculation, although well-meaning and well-motivated speculation.

    It is worth remembering that if the lessons of history are any guide, most forefront physical ideas are wrong. If they weren’t, anyone could do theoretical physics. It took several centuries or, if one counts back to the science of the Greeks, several millennia of hits and misses to come up with the Standard Model.

    So this is where we are. Are great new experimental insights just around the corner that may validate, or invalidate, some of the grander speculations of theoretical physicists? Or are we on the verge of a desert where nature will give us no hint of what direction to search in to probe deeper into the underlying nature of the cosmos? We’ll find out, and we will have to live with the new reality either way.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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.

     
  • richardmitnick 8:50 am on September 1, 2016 Permalink | Reply
    Tags: , , , How Much More Can We Learn About the Universe?, Lawrence Krauss, ,   

    From Nautilus: “How Much More Can We Learn About the Universe?” Lawrence M. Krauss 

    Nautilus

    Nautilus

    September 1, 2016
    Lawrence M. Krauss

    1
    Jackie Ferrentino

    As a cosmologist, some of the questions I hear most frequently after a lecture include: What lies beyond our universe? What is our universe expanding into? Will our universe expand forever? These are natural questions to ask. But there is an even deeper question at play here. Fundamentally what we really want to know is: Is there a boundary to our knowledge? Are there fundamental limits to science?

    The answer, of course, is that we don’t know in advance. We won’t know if there is a limit to knowledge unless we try to get past it. At the moment, we have no sign of one. We may be facing roadblocks, but those give every indication of being temporary. Some people say to me: “We will never know how the universe began.” “We can never know what happened before the Big Bang.” These statements demonstrate a remarkable conceit, by suggesting we can know in advance the locus of all those things that we cannot know. This is not only unsubstantiated, but the history of science so far has demonstrated no such limits. And in my own field, cosmology, our knowledge has increased in ways that no one foresaw even 50 years ago.

    2
    ON A CLEAR DAY YOU CAN’T SEE FOREVER: The farthest you see, in principle, is 45.3 billion light-years. Although that represents a direct limitation on our knowledge, it doesn’t keep us from grasping the basic workings of nature. NASA / Bill Ingalls

    his is not to say that nature doesn’t impose limits on what we can observe and how we can observe it. For example, the Heisenberg uncertainty principle constrains what we can know about the motion of a particle at any time, and the speed of light restricts how far we can see or travel in a given interval. But these limits merely tell us what we cannot observe, not what we cannot eventually learn. The uncertainty principle hasn’t gotten in the way of learning the rules of quantum mechanics, understanding the behavior of atoms, or discovering that so-called virtual particles, which we can never see directly, nevertheless exist.

    The observation that the universe is expanding does imply a beginning, because if we extrapolate backward, then at some point in the distant past, everything in our observable universe was co-located at a single point. At that instant, which now goes by the name of the Big Bang, the laws of physics as we know them break down, because general relativity, which describes gravity, cannot be successfully integrated with quantum mechanics, which describes physics on microscopic length scales. But most scientists do not view this as a fundamental boundary to knowledge, because we expect that general relativity will have to be modified as part of a consistent quantum theory. String theory is one of the major ongoing efforts to do so.

    Given such a theory, we might be able to answer the question of what, if anything, came before the Big Bang. The simplest possible answer is perhaps also the least satisfying. Both special and general relativity tie together space and time into a single entity: spacetime. If space was created in the Big Bang, then perhaps time was as well. In that case, there was no “before.” It simply wouldn’t be a good question. This is not the only possible answer, though, and we will need to await a quantum theory of gravity and its experimental confirmation before we will have any confidence in our reply.

    Then there is the question of whether we can know what lies beyond our own universe, spatially. What are the boundaries of our universe? Again, we can hazard a guess. If our spacetime arose spontaneously—which, as I argued at length in my last book, A Universe from Nothing, seems the most likely possibility—then it probably has zero total energy: The energy represented by matter is exactly offset by the energy represented by gravitational fields. Put simply, something can arise from nothing if the something amounts to nothing. Right now, the only universe that we can verify has zero total energy is a closed universe. Such a universe is finite yet unbounded. Just like you can move around the surface of a sphere forever without encountering any boundaries, the same may be true of our universe. If we look far enough in one direction, we would see the back of our heads.

    In practice, we cannot do that, probably because our visible universe is only part of a much larger volume. The reason has to do with something called inflation. Most universes that arise spontaneously with microscopic size will re-collapse in a microscopic time, rather than endure for billions of years. But, in some, empty space will be endowed with energy, and that will cause the universe to expand exponentially fast, at least for a brief period. We think that such a period of inflation occurred during the earliest moments of our Big Bang expansion and prevented the universe from re-collapsing immediately. In the process, the universe puffed up in size to become so great in extent that, for all intents and purposes, it would now appear flat and infinite—like a cornfield in Kansas that looks infinite despite being located on the huge sphere we call Earth. This is why we don’t see the backs of our heads when we look up in space, even though our universe may be closed on its largest scales. In principle, though, we could see the whole thing if we waited long enough, as long as inflation hadn’t resumed in our visible universe, and is not occurring elsewhere in regions of space we cannot observe.

    As for the possibility that regions we cannot yet observe, or may never observe, may be inflating, in fact our current theories suggest that this is the most likely possibility. If we consider the phrase “our universe” to refer to that region of space with which we once could have communicated or with which we one day may communicate, then inflation generally creates other universes beyond ours. Inflation may have been brief within our volume of space, but the rest of space expands exponentially forever, with isolated regions like ours occasionally decoupling from the expansion, just as isolated ice patches can form on the surface of fast-moving water when the temperature is below freezing. Each such universe had a beginning, pegged to the time when inflation ended within its spatial volume. In this case, the beginning of our universe may not have been the beginning of time itself—further reason to doubt whether the Big Bang represents an ultimate limit to our knowledge.

    3
    COLLIDING GALAXIES: Such cosmic commotion will one day cease to occur, and observers in the distant future may never realize how dynamic our universe once was. NASA

    Depending on the processes that cause each universe to decouple from the background space, the laws of physics might be different in each one. We have come to call this collection of possible universes a “multiverse.” The idea of a multiverse has gained traction in the scientific community not only because it is motivated by phenomena like inflation, but also because the possibility of many different universes, each with its own laws of physics, might explain various seemingly inexplicable fundamental parameters of our universe. Those parameters are simply the values that randomly arose when our universe was born.

    If other universes are out there, they are separated from ours by huge distances and recede at super-light relative velocities, so we can never detect them directly. Is the multiverse then just metaphysics? Does verifying the possible existence of a multiverse thus represent a fundamental boundary to our knowledge? The answer is: not necessarily. Although we may never see another universe directly, we can still test the theory that may have produced it empirically—for example, by observing gravitational waves that inflation would produce. This would allow us in principle to test the detailed nature of the inflationary process that resulted in our universe. These waves are similar to the gravitational waves recently discovered by LIGO, but differ in their origin. They come not from cataclysmic events such as the collisions of massive black holes in distant galaxies, but from the earliest moments of the Big Bang, during the putative period of inflation. If we can detect them directly—as we might be able to do in a variety of experiments that are now looking for the signature they would leave in the cosmic microwave background radiation left over from the Big Bang—we can probe the physics of inflation and then determine whether eternal inflation is a consequence of this physics. Thus, indirectly, we could test whether other universes must exist, even if we cannot detect them directly.

    In short, we have discovered that even the very deepest metaphysical questions—which previously we might have imagined would never be empirically addressable, including the possible existence of other universes—may in fact be accessible, if we are clever enough. No limits to what we may learn from the application of reason combined with experimental observation are yet known.

    A universe without limits is appealing and motivates us to continue searching. But can we be confident there will be no limits to our knowledge, ever? Not quite.

    Inflation does place a fundamental limit on knowledge—specifically, knowledge of the past. It essentially resets the universe, destroying potentially all the information about the dynamical processes that preceded it. The rapid expansion of space during inflation severely dilutes the contents of any region. So it may have wiped out traces of, for example, magnetic monopoles, a type of particle that theory suggests the very early universe produced in profusion. That was one of the original virtues of inflation: It reconciled the fact we have never seen such particles with predictions of their production. But in getting rid of a discrepancy, inflation erased aspects of our past.

    Worse, the erasure may not be over. We are apparently living in another period of inflation right now. Measurements of the recession of distant galaxies indicates that the expansion of our universe is currently speeding up, not slowing down, as it would be if the dominant gravitational energy resided in matter or radiation, and not in empty space. We currently have no understanding of the origin of this energy. Each of the potential explanations suggests fundamental limits to the progress of knowledge and even to our very existence.

    The energy of empty space could suddenly disappear if the universe undergoes some kind of phase transition, a cosmic version of steam condensing into liquid water. If that were to happen, the nature of fundamental forces might change, and all the structures we see in the universe, from atoms on up, might become unstable or disappear. We would disappear along with everything else.

    But even if the expansion continues, the future is still rather dismal. Within about 2 trillion years—which may seem like a long time on human scales, but is not so long on cosmic scales—the rest of the universe will disappear from our view. Any observers who evolve on planets around stars in this distant future will imagine that they live on a single galaxy surrounded by an eternal empty space, with no signs of acceleration or even any evidence of an earlier Big Bang. Just as we have lost sight of monopoles, they will be blind to the history that we readily see. (To be sure, they may have access to observable phenomenon we do not yet have access to, so we shouldn’t feel too superior.)

    Either way, we should enjoy our brief moment in the sun and learn what we can, while we can. Work harder, graduate students!

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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.

     
  • richardmitnick 5:53 pm on June 26, 2016 Permalink | Reply
    Tags: , Lawrence Krauss, Philosophy and Religion,   

    From The Atlantic: “Has Physics Made Philosophy and Religion Obsolete?” 2012 but Very Important 

    Atlantic Magazine

    The Atlantic Magazine

    Apr 23, 2012
    Ross Andersen

    1
    No image caption. No image credit.

    It is hard to know how our future descendants will regard the little sliver of history that we live in. It is hard to know what events will seem important to them, what the narrative of now will look like to the twenty-fifth century mind. We tend to think of our time as one uniquely shaped by the advance of technology, but more and more I suspect that this will be remembered as an age of cosmology—as the moment when the human mind first internalized the cosmos that gave rise to it. Over the past century, since the discovery that our universe is expanding, science has quietly begun to sketch the structure of the entire cosmos, extending its explanatory powers across a hundred billion galaxies, to the dawn of space and time itself. It is breathtaking to consider how quickly we have come to understand the basics of everything from star formation to galaxy formation to universe formation. And now, equipped with the predictive power of quantum physics, theoretical physicists are beginning to push even further, into new universes and new physics, into controversies once thought to be squarely within the domain of theology or philosophy.

    In January, Lawrence Krauss, a theoretical physicist and Director of the Origins Institute at Arizona State University, published A Universe From Nothing: Why There Is Something Rather Than Nothing, a book that, as its title suggests, purports to explain how something—and not just any something, but the entire universe—could have emerged from nothing, the kind of nothing implicated by quantum field theory. But before attempting to do so, the book first tells the story of modern cosmology, whipping its way through the big bang to microwave background radiation and the discovery of dark energy. It’s a story that Krauss is well positioned to tell; in recent years he has emerged as an unusually gifted explainer of astrophysics. One of his lectures has been viewed over a million times on YouTube and his cultural reach extends to some unlikely places—last year Miley Cyrus came under fire when she tweeted a quote from Krauss that some Christians found offensive. Krauss’ book quickly became a bestseller, drawing raves from popular atheists like Sam Harris and Richard Dawkins, the latter of which even compared it to The Origin of Species for the way its final chapters were supposed to finally upend the “last trump card of the theologian.”

    By early spring, media coverage of A Universe From Nothing seemed to have run its course, but then on March 23rd the New York Times ran a blistering review of the book, written by David Albert, a philosopher of physics from Columbia University. Albert, who has a PhD in theoretical physics, argued that Krauss’ “nothing” was in fact a something and did so in uncompromising terms:

    “The particular, eternally persisting, elementary physical stuff of the world, according to the standard presentations of relativistic quantum field theories, consists (unsurprisingly) of relativistic quantum fields… they have nothing whatsoever to say on the subject of where those fields came from, or of why the world should have consisted of the particular kinds of fields it does, or of why it should have consisted of fields at all, or of why there should have been a world in the first place. Period. Case closed. End of story.”

    Because the story of modern cosmology has such deep implications for the way that we humans see ourselves and the universe, it must be told correctly and without exaggeration—in the classroom, in the press and in works of popular science. To see two academics, both versed in theoretical physics, disagreeing so intensely on such a fundamental point is troubling. Not because scientists shouldn’t disagree with each other, but because here they’re disagreeing about a claim being disseminated to the public as a legitimate scientific discovery. Readers of popular science often assume that what they’re reading is backed by a strong consensus. Having recently interviewed Krauss for a different project, I reached out to him to see if he was interested in discussing Albert’s criticisms with me. He said that he was, and mentioned that he would be traveling to New York on April 20th to speak at a memorial service for Christopher Hitchens. As it happened, I was also due to be in New York that weekend and so, last Friday, we were able to sit down for the extensive, and at times contentious, conversation that follows.

    I know that you’re just coming from Christopher Hitchens’ memorial service. How did that go?

    Krauss: It was a remarkable event for a remarkable man, and I felt very fortunate to be there. I was invited to give the opening presentation in front of all of these literary figures and dignitaries of various sorts, and so I began the only way I think you can begin, and that’s with music from Monty Python. That got me over my initial stage fright and my concern about what to say about someone as extraordinary as Christopher. I was able to talk about a lot of the aspects of Christopher that people may not know about, including the fact that he was fascinated by science. And I also got to talk about what it felt like to be his friend.

    I closed with an anecdote, a true story about the last time I was with him. I was reading the New York Times at his kitchen table, and there was an article about the ongoing effort to keep Catholic students at elite colleges like Yale from losing their faith. The article said something like “faced with Nietzsche, coed dorms, Hitchens, and beer pong, students are likely to stray.” There are two really amazing aspects of that. For one, to be so culturally ubiquitous that you can be mentioned in a sentence like that without any further explanation is pretty exceptional. But also to be sandwiched between “Nietzsche” and “beer pong” is an honor that very few of us can ever aspire to.

    I want to start with a general question about the relationship between philosophy and physics. There has been a fair amount of sniping between these two disciplines over the past few years. Why the sudden, public antagonism between philosophy and physics?

    Krauss: That’s a good question. I expect it’s because physics has encroached on philosophy. Philosophy used to be a field that had content, but then “natural philosophy” became physics, and physics has only continued to make inroads. Every time there’s a leap in physics, it encroaches on these areas that philosophers have carefully sequestered away to themselves, and so then you have this natural resentment on the part of philosophers. This sense that somehow physicists, because they can’t spell the word “philosophy,” aren’t justified in talking about these things, or haven’t thought deeply about them—

    Is that really a claim that you see often?

    Krauss: It is. Philosophy is a field that, unfortunately, reminds me of that old Woody Allen joke, “those that can’t do, teach, and those that can’t teach, teach gym.” And the worst part of philosophy is the philosophy of science; the only people, as far as I can tell, that read work by philosophers of science are other philosophers of science. It has no impact on physics what so ever, and I doubt that other philosophers read it because it’s fairly technical. And so it’s really hard to understand what justifies it. And so I’d say that this tension occurs because people in philosophy feel threatened, and they have every right to feel threatened, because science progresses and philosophy doesn’t.

    2
    Lawrence Krauss, author of A Universe From Nothing: Why There Is Something Rather Than Nothing

    On that note, you were recently quoted as saying that philosophy “hasn’t progressed in two thousand years.” But computer science, particularly research into artificial intelligence was to a large degree built on foundational work done by philosophers in logic and other formal languages. And certainly philosophers like John Rawls have been immensely influential in fields like political science and public policy. Do you view those as legitimate achievements?

    Krauss: Well, yeah, I mean, look I was being provocative, as I tend to do every now and then in order to get people’s attention. There are areas of philosophy that are important, but I think of them as being subsumed by other fields. In the case of descriptive philosophy you have literature or logic, which in my view is really mathematics. Formal logic is mathematics, and there are philosophers like Wittgenstein that are very mathematical, but what they’re really doing is mathematics—it’s not talking about things that have affected computer science, it’s mathematical logic. And again, I think of the interesting work in philosophy as being subsumed by other disciplines like history, literature, and to some extent political science insofar as ethics can be said to fall under that heading. To me what philosophy does best is reflect on knowledge that’s generated in other areas.

    I’m not sure that’s right. I think that in some cases philosophy actually generates new fields. Computer science is a perfect example. Certainly philosophical work in logic can be said to have been subsumed by computer science, but subsumed might be the wrong word—

    Krauss: Well, you name me the philosophers that did key work for computer science; I think of John Von Neumann and other mathematicians, and—

    But Bertrand Russell paved the way for Von Neumann.

    Krauss: But Bertrand Russell was a mathematician. I mean, he was a philosopher too and he was interested in the philosophical foundations of mathematics, but by the way, when he wrote about the philosophical foundations of mathematics, what did he do? He got it wrong.

    But Einstein got it wrong, too—

    Krauss: Sure, but the difference is that scientists are really happy when they get it wrong, because it means that there’s more to learn. And look, one can play semantic games, but I think that if you look at the people whose work really pushed the computer revolution from Turing to Von Neumann and, you’re right, Bertrand Russell in some general way, I think you’ll find it’s the mathematicians who had the big impact. And logic can certainly be claimed to be a part of philosophy, but to me the content of logic is mathematical.

    Do you find this same tension between theoretical and empirical physics?

    Krauss: Sometimes, but it shouldn’t be there. Physics is an empirical science. As a theoretical physicist I can tell you that I recognize that it’s the experiment that drives the field, and it’s very rare to have it go the other way; Einstein is of course the obvious exception, but even he was guided by observation. It’s usually the universe that’s surprising us, not the other way around.

    Moving on to your book “A Universe From Nothing,” what did you hope to accomplish when you set out to write it?

    Krauss: Every time I write a book, I try and think of a hook. People are interested in science, but they don’t always know they’re interested in science, and so I try to find a way to get them interested. Teaching and writing, to me, is really just seduction; you go to where people are and you find something that they’re interested in and you try and use that to convince them that they should be interested in what you have to say.

    The religious question “why is there something rather than nothing,” has been around since people have been around, and now we’re actually reaching a point where science is beginning to address that question. And so I figured I could use that question as a way to celebrate the revolutionary changes that we’ve achieved in refining our picture of the universe. I didn’t write the book to attack religion, per se. The purpose of the book is to point out all of these amazing things that we now know about the universe. Reading some of the reactions to the book, it seems like you automatically become strident the minute you try to explain something naturally.

    Richard Dawkins wrote the afterword for the book—and I thought it was pretentious at the time, but I just decided to go with it—where he compares the book to The Origin of Species. And of course as a scientific work it doesn’t some close to The Origin of Species, which is one of the greatest scientific works ever produced. And I say that as a physicist; I’ve often argued that Darwin was a greater scientist than Einstein. But there is one similarity between my book and Darwin’s—before Darwin life was a miracle; every aspect of life was a miracle, every species was designed, etc. And then what Darwin showed was that simple laws could, in principle, plausibly explain the incredible diversity of life. And while we don’t yet know the ultimate origin of life, for most people it’s plausible that at some point chemistry became biology. What’s amazing to me is that we’re now at a point where we can plausibly argue that a universe full of stuff came from a very simple beginning, the simplest of all beginnings: nothing. That’s been driven by profound revolutions in our understanding of the universe, and that seemed to me to be something worth celebrating, and so what I wanted to do was use this question to get people to face this remarkable universe that we live in.

    Your book argues that physics has definitively demonstrated how something can come from nothing. Do you mean that physics has explained how particles can emerge from so-called empty space, or are you making a deeper claim?

    Krauss: I’m making a deeper claim, but at the same time I think you’re overstating what I argued. I don’t think I argued that physics has definitively shown how something could come from nothing; physics has shown how plausible physical mechanisms might cause this to happen. I try to be intellectually honest in everything that I write, especially about what we know and what we don’t know. If you’re writing for the public, the one thing you can’t do is overstate your claim, because people are going to believe you. They see I’m a physicist and so if I say that protons are little pink elephants, people might believe me. And so I try to be very careful and responsible. We don’t know how something can come from nothing, but we do know some plausible ways that it might.

    But I am certainly claiming a lot more than just that. That it’s possible to create particles from no particles is remarkable—that you can do that with impunity, without violating the conservation of energy and all that, is a remarkable thing. The fact that “nothing,” namely empty space, is unstable is amazing. But I’ll be the first to say that empty space as I’m describing it isn’t necessarily nothing, although I will add that it was plenty good enough for Augustine and the people who wrote the Bible. For them an eternal empty void was the definition of nothing, and certainly I show that that kind of nothing ain’t nothing anymore.

    But debating physics with Augustine might not be an interesting thing to do in 2012.

    Krauss: It might be more interesting than debating some of the moronic philosophers that have written about my book. Given what we know about quantum gravity, or what we presume about quantum gravity, we know you can create space from where there was no space. And so you’ve got a situation where there were no particles in space, but also there was no space. That’s a lot closer to “nothing.”

    But of course then people say that’s not “nothing,” because you can create something from it. They ask, justifiably, where the laws come from. And the last part of the book argues that we’ve been driven to this notion—a notion that I don’t like—that the laws of physics themselves could be an environmental accident. On that theory, physics itself becomes an environmental science, and the laws of physics come into being when the universe comes into being. And to me that’s the last nail in the coffin for “nothingness.”

    It sounds like you’re arguing that ‘nothing’ is really a quantum vacuum, and that a quantum vacuum is unstable in such a way as to make the production of matter and space inevitable. But a quantum vacuum has properties. For one, it is subject to the equations of quantum field theory. Why should we think of it as nothing?

    Krauss: That would be a legitimate argument if that were all I was arguing. By the way it’s a nebulous term to say that something is a quantum vacuum in this way. That’s another term that these theologians and philosophers have started using because they don’t know what the hell it is, but it makes them sound like they know what they’re talking about. When I talk about empty space, I am talking about a quantum vacuum, but when I’m talking about no space whatsoever, I don’t see how you can call it a quantum vacuum. It’s true that I’m applying the laws of quantum mechanics to it, but I’m applying it to nothing, to literally nothing. No space, no time, nothing. There may have been meta-laws that created it, but how you can call that universe that didn’t exist “something” is beyond me. When you go to the level of creating space, you have to argue that if there was no space and no time, there wasn’t any pre-existing quantum vacuum. That’s a later stage.

    Even if you accept this argument that nothing is not nothing, you have to acknowledge that nothing is being used in a philosophical sense. But I don’t really give a damn about what “nothing” means to philosophers; I care about the “nothing” of reality. And if the “nothing” of reality is full of stuff, then I’ll go with that.

    But I don’t have to accept that argument, because space didn’t exist in the state I’m talking about, and of course then you’ll say that the laws of quantum mechanics existed, and that those are something. But I don’t know what laws existed then. In fact, most of the laws of nature didn’t exist before the universe was created; they were created along with the universe, at least in the multiverse picture. The forces of nature, the definition of particles—all these things come into existence with the universe, and in a different universe, different forces and different particles might exist. We don’t yet have the mathematics to describe a multiverse, and so I don’t know what laws are fixed. I also don’t have a quantum theory of gravity, so I can’t tell you for certain how space comes into existence, but to make the argument that a quantum vacuum that has particles is the same as one that doesn’t have particles is to not understand field theory.

    I’m not sure that anyone is arguing that they’re the same thing–

    Krauss: Well, I read a moronic philosopher who did a review of my book in the New York Times who somehow said that having particles and no particles is the same thing, and it’s not. The quantum state of the universe can change and it’s dynamical. He didn’t understand that when you apply quantum field theory to a dynamic universe, things change and you can go from one kind of vacuum to another. When you go from no particles to particles, it means something.

    I think the problem for me, coming at this as a layperson, is that when you’re talking about the explanatory power of science, for every stage where you have a “something,”—even if it’s just a wisp of something, or even just a set of laws—there has to be a further question about the origins of that “something.” And so when I read the title of your book, I read it as “questions about origins are over.”

    Krauss: Well, if that hook gets you into the book that’s great. But in all seriousness, I never make that claim. In fact, in the preface I tried to be really clear that you can keep asking “Why?” forever. At some level there might be ultimate questions that we can’t answer, but if we can answer the “How?” questions, we should, because those are the questions that matter. And it may just be an infinite set of questions, but what I point out at the end of the book is that the multiverse may resolve all of those questions. From Aristotle’s prime mover to the Catholic Church’s first cause, we’re always driven to the idea of something eternal. If the multiverse really exists, then you could have an infinite object—infinite in time and space as opposed to our universe, which is finite. That may beg the question as to where the multiverse came from, but if it’s infinite, it’s infinite. You might not be able to answer that final question, and I try to be honest about that in the book. But if you can show how a set of physical mechanisms can bring about our universe, that itself is an amazing thing and it’s worth celebrating. I don’t ever claim to resolve that infinite regress of why-why-why-why-why; as far as I’m concerned it’s turtles all the way down. The multiverse could explain it by being eternal, in the same way that God explains it by being eternal, but there’s a huge difference: the multiverse is well motivated and God is just an invention of lazy minds.

    In the past you’ve spoken quite eloquently about the Multiverse, this idea that our universe might be one of many universes, perhaps an infinite number. In your view does theoretical physics give a convincing account of how such a structure could come to exist?

    Krauss: In certain ways, yes—in other ways, no. There are a variety of multiverses that people in physics talk about. The most convincing one derives from something called inflation, which we’re pretty certain happened because it produces effects that agree with almost everything we can observe. From what we know about particle physics, it seems quite likely that the universe underwent a period of exponential expansion early on. But inflation, insofar as we understand it, never ends—it only ends in certain regions and then those regions become a universe like ours. You can show that in an inflationary universe, you produce a multiverse, you produce an infinite number of causally separated universes over time, and the laws of physics are different in each one. There’s a real mechanism where you can calculate it.

    And all of that comes, theoretically, from a very small region of space that becomes infinitely large over time. There’s a calculable multiverse; it’s almost required for inflation—it’s very hard to get around it. All the evidence suggests that our universe resulted from a period of inflation, and it’s strongly suggestive that well beyond our horizon there are other universes that are being created out of inflation, and that most of the multiverse is still expanding exponentially.

    Is there an empirical frontier for this? How do we observe a multiverse?

    Krauss: Right. How do you tell that there’s a multiverse if the rest of the universes are outside your causal horizon? It sounds like philosophy. At best. But imagine that we had a fundamental particle theory that explained why there are three generations of fundamental particles, and why the proton is two thousand times heavier than the electron, and why there are four forces of nature, etc. And it also predicted a period of inflation in the early universe, and it predicts everything that we see and you can follow it through the entire evolution of the early universe to see how we got here. Such a theory might, in addition to predicting everything we see, also predict a host of universes that we don’t see. If we had such a theory, the accurate predictions it makes about what we can see would also make its predictions about what we can’t see extremely likely. And so I could see empirical evidence internal to this universe validating the existence of a multiverse, even if we could never see it directly.

    You have said that your book is meant to describe “the remarkable revolutions that have taken place in our understanding of the universe over the past 50 years–revolutions that should be celebrated as the pinnacle of our intellectual experience.” I think that’s a worthy project and, like you, I find it lamentable that some of physics’ most extraordinary discoveries have yet to fully penetrate our culture. But might it be possible to communicate the beauty of those discoveries without tacking on an assault on previous belief systems, especially when those belief systems aren’t necessarily scientific?

    Krauss: Well, yes. I’m sympathetic to your point in one sense, and I’ve had this debate with Richard Dawkins; I’ve often said to him that if you want people to listen to you, the best way is not to go up to them and say, “You’re stupid.” Somehow it doesn’t get through.

    It’s a fine line and it’s hard to tell where to fall on this one. What drove me to write this book was this discovery that the nature of “nothing” had changed, that we’ve discovered that “nothing” is almost everything and that it has properties. That to me is an amazing discovery. So how do I frame that? I frame it in terms of this question about something coming from nothing. And part of that is a reaction to these really pompous theologians who say, “out of nothing, nothing comes,” because those are just empty words. I think at some point you need to provoke people. Science is meant to make people uncomfortable. And whether I went too far on one side or another of that line is an interesting question, but I suspect that if I can get people to be upset about that issue, then on some level I’ve raised awareness of it.

    The unfortunate aspect of it is, and I’ve come to realize this recently, is that some people feel they don’t even need to read the book, because they think I’ve missed the point of the fundamental theological question. But I suspect that those people weren’t open to it anyway. I think Steven Weinberg said it best when he said that science doesn’t make it impossible to believe in God, it just makes it possible to not believe in God. That’s a profoundly important point, and to the extent that cosmology is bringing us to a place where we can address those very questions, it’s undoubtedly going to make people uncomfortable. It was a judgment call on my part and I can’t go back on it, so it’s hard to know.

    You’ve developed this wonderful ability to translate difficult scientific concepts into language that can enlighten, and even inspire a layperson. There are people in faith communities who are genuinely curious about physics and cosmology, and your book might be just the thing to quench and multiply that curiosity. But I worry that by framing these discoveries in language that is in some sense borrowed from the culture war, that you run the risk of shrinking the potential audience for them—and that could ultimately be a disservice to the ideas.

    Krauss: Ultimately, it might be. I’ve gone to these fundamentalist colleges and I’ve gone to Fox News and it’s interesting, the biggest impact I’ve ever had is when I said, “you don’t have to be an atheist to believe in evolution.” I’ve had young kids come up to me and say that affected them deeply. So yes it’s nice to point that out, but I actually think that if you read my book I never say that we know all the answers, I say that it’s pompous to say that we can’t know the answers. And so yeah I think that maybe there will be some people who are craving this stuff and who won’t pick up my book because of the way I’ve framed it, but at the same time I do think that people need to be aware that they can be brave enough to ask the question “Is it possible to understand the universe without God?” And so you’re right that I’m going to lose some people, but I’m hoping that at the same time I’ll gain some people who are going to be brave enough to come out of the closet and ask that question. And that’s what amazes me, that nowadays when you simply ask the question you’re told that you’re offending people.

    But let me bring that back full circle. You opened this conversation talking about seduction. You’re not giving an account of seduction right now.

    Krauss: That’s true, but let me take it back full circle to Hitchens. What Christopher had was charm, humor, wit and culture as weapons against nonsense, and in my own small way what I try and do in my books is exactly that. I try and infuse them with humor and culture and that’s the seduction part. And in this case the seduction might be causing people to ask, “How can he say that? How can he have the temerity to suggest that it’s possible to get something from nothing? Let me see what’s wrong with these arguments.” If I’d just titled the book “A Marvelous Universe,” not as many people would have been attracted to it. But it’s hard to know. I’m acutely aware of this seduction problem, and my hope is that what I can do is get people to listen long enough to where I can show some of what’s going on, and at the same time make them laugh.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
    • makingsenseofcomplications 9:26 am on June 27, 2016 Permalink | Reply

      I haven’t read this yet, but believe the three address different facets of the (necessarily) human experience. I prefer the scientific realm, but religion and philosophy are unmistakable elements of the human experience, however illogical or off-base they may be.

      Like

c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: