A group of physicists are questioning our understanding of how quarks – a type of elementary particle – arrange themselves under extreme conditions. And their quest is revealing that elements beyond the edge of the periodic table might be far more weird than we thought.
Periodic table Sept 2017. Wikipedia
Deep in the depths of the periodic table there are monsters made of a unique arrangement of subatomic particles. As far as elements go, they come no bigger than oganesson – a behemoth that contains 118 protons and has an atomic mass of just under 300.
That’s not to say protons and neutrons can’t be arranged into even bigger clumps and still remain somewhat stable for longer than an eye blink. But for all practical purposes, nobody has discovered it yet.
While scientists speculate over how far the frontiers of the periodic table stretch, it’s becoming clear that as atoms get bigger, the usual rules governing their behaviour change.
In this latest study, physicists from the University of Toronto argue that the constituent particles making up an atom’s protons and neutrons could break their usual bonds under extreme conditions and still retain enough stability for the atom to stick around.
There are six types of these particles, called quarks, with the rather odd names of up, down, charm, strange, top, and bottom. Protons contain two up types and a down type. Neutrons, on the other hand, are made of two downs and a single up.
Quarks aren’t limited to these configurations, though finding other arrangements is often rare thanks to the fact few stay stable very long.
A little over thirty years ago, a physicist named Edward Witten proposed that the energy keeping combinations of quarks in triplets could achieve something of a balance if put under sufficient pressure, such as that inside a neutron star.
This ‘strange quark matter’ (or SQM) would be a relatively equal mix of up, down, and strange quarks arranged not in threes, but as a liquid of numerous buzzing particles.
Given the fact up and down quarks get along well enough to form teams inside protons and neutrons, the possibility of making quark matter without strange quarks to mix things up has been generally dismissed.
According to physicists Bob Holdom, Jing Ren, and Chen Zhang, doing the actual sums reveals up-down quark matter, or udQM, might not only be possible, but preferable.
“Physicists have been searching for SQM for decades,” the researchers told Lisa Zyga at phys.org. “From our results, many searches may have been looking in the wrong place.”
The team went back to basics and question the lowest energy state of a big bunch of squirming quarks.
They discovered that the ground state – that comfortable lobby of energy levels for particles – for udQM could actually be lower than both SQM and the ground state of the triplets inside protons and neutrons.
So if bunches of quarks are given enough of a push, they could force the ups and downs to pool into a liquid mess at energies that don’t need the help of strange quarks.
Neutron stars could provide just such a squeeze, but it’s no secret that the hearts of atoms themselves are pretty intense places as far as forces go.
The team suggest elements with atomic masses greater than 300 might also provide the right conditions to force up and down quarks to loosen up and party.
Making these elements would be a challenge that would require some way to pile on the neutrons to make supermassive elements stable enough.
But the lower ground states of udQM point the way to stable regions beyond the edges of the periodic table.
Exactly what these heavy elements look like or how they behave is hard to say for now, but it’s unlikely they’d be following the usual rules.
There’s also a chance that udQM could shoot across the Universe in the form of cosmic rays, and potentially be caught here on Earth. Or even produced inside particle accelerators.
“Knowing better where to look for udQM might then help to achieve an old idea: that of using quark matter as a new source of energy,” the researchers claim.
Stable droplets of quarks wouldn’t behave like usual quark clusters found in protons and neutrons, with lower masses that could potentially make them easier to control.
Quark matter reactors sound like the stuff of science fiction. But if this research is anything to go by, a whole new field of applied physics could be just over the horizon.
Established in 1827, the University of Toronto has one of the strongest research and teaching faculties in North America, presenting top students at all levels with an intellectual environment unmatched in depth and breadth on any other Canadian campus.
Established in 1827, the University of Toronto has one of the strongest research and teaching faculties in North America, presenting top students at all levels with an intellectual environment unmatched in depth and breadth on any other Canadian campus.
In an exciting first, Indian scientists have discovered a sub-Saturn exoplanet orbiting a Sun-like star around 600 light-years away.
The planet has been named EPIC 211945201b or K2-236b and it’s big – around 27 times more massive than Earth. The find sees India join a small group of countries to have confirmed a planet outside our Solar System.
Exoplanets themselves aren’t that rare these days – we have confirmed the existence of 3,786 of them.
But the vast majority (~2,600) have been spotted and then confirmed as planets by NASA’s Kepler space telescope.
This latest planet was also first spotted and listed as a candidate planet by Kepler, but it was a team of Indian scientists that confirmed it was a planet, rather than simply a comet or another astronomical object – which is the tricky part.
ISRO
The team was led by Abhijit Chakraborty from the Physical Research Laboratory (PRL), Ahmedabad.
They spent a year a half at PRL’s Gurushikhar Observatory in Mount Abu, India, studying the changes in light coming from the planet’s host star, EPIC 211945201 or K2-236, and performing an independent confirmation of its mass.
Isro-PRL’s observatory at Mt Abu
“We report here strong evidence for a sub-Saturn around EPIC 211945201 and confirm its planetary nature,” the team reports in the American Astronomical Society’s The Astronomical Journal.
While the planet is orbiting a Sun-like star, it’s also roughly more than seven times closer to its star than Earth is to the Sun, which means the temperature could be around 600 degrees Celsius and likely too hot and dry to support life.
Here’s what we know so far:
EPIC 211945201b’s mass is around 27 times that of Earth’s and it’s estimated to be around six times greater in radius.
The planet orbits a Sun-like star 600 light-years away.
It’s estimated to be more than seven times closer to its star than we are, which means a year lasts just roughly 19.5 days.
It also means the planet’s surface temperature is roughly 600 degrees Celsius.
Importantly, this discovery could help scientists understand how these types of planets form so close to their host star.
Beyond that, it shows that India now has the technology and expertise to confirm exoplanets on their own.
The Indian Space Research Organisation (ISRO) has made great strides in recent years, setting new records for satellite launches and putting a probe into orbit around Mars – all for incredibly efficient prices.
Obviously when it comes to space, it doesn’t matter who’s doing the research. But having more minds and telescopes searching our galaxy for signs of extraterrestrial life or even future homes for humanity is never a bad thing.
Known as the cradle of Space Sciences in India, the Physical Research Laboratory ( PRL ) was founded in 1947 by Dr. Vikram Sarabhai. As a unit of Department of Space, Government of India, PRL carries out fundamental research in selected areas of Physics, Space & Atmospheric Sciences, Astronomy, Astrophysics & Solar Physics, and Planetary & Geo-Sciences.
India decided to go to space when Indian National Committee for Space Research (INCOSPAR) was set up by the Government of India in 1962. With the visionary Dr Vikram Sarabhai at its helm, INCOSPAR set up the Thumba Equatorial Rocket Launching Station (TERLS) in Thiruvananthapuram for upper atmospheric research.
Indian Space Research Organisation, formed in 1969, superseded the erstwhile INCOSPAR. Vikram Sarabhai, having identified the role and importance of space technology in a Nation’s development, provided ISRO the necessary direction to function as an agent of development. ISRO then embarked on its mission to provide the Nation space based services and to develop the technologies to achieve the same independently.
Throughout the years, ISRO has upheld its mission of bringing space to the service of the common man, to the service of the Nation. In the process, it has become one of the six largest space agencies in the world. ISRO maintains one of the largest fleet of communication satellites (INSAT) and remote sensing (IRS) satellites, that cater to the ever growing demand for fast and reliable communication and earth observation respectively. ISRO develops and delivers application specific satellite products and tools to the Nation: broadcasts, communications, weather forecasts, disaster management tools, Geographic Information Systems, cartography, navigation, telemedicine, dedicated distance education satellites being some of them.
richardmitnick
4:23 pm on May 21, 2018 Permalink
| Reply Tags: Asteroid 2015 BZ509, Astronomy ( 6,647 ), Astrophysics ( 3,782 ), Basic Research ( 9,237 ), Cosmology ( 3,979 ), Jupiter tugs on the asteroid which prevents it from tumbling Sun-ward and the Sun tugs it back preventing it from falling into Jupiter, Of the thousands and thousands of asteroids and comets and planetesimals and planets and moons only 95 are known to orbit the Sun clockwise or retrograde. This makes them pretty rare, Science Alert, So far "it's one-of-a-kind", They found that it went all the way back to the birth of the Solar System 4.5 billion years ago and it could maintain that orbit for 43 billion years
Interstellar asteroid ‘Oumuamua raised an interesting possibility: if objects could enter our Solar System from somewhere out beyond its reaches, maybe it’s happened before. New research has found that that is indeed the case – and that interstellar object has been living here a long time.
It’s the first known permanent fixture of our Solar System that wasn’t formed here.
Pannstars telescope, U Hawaii, Mauna Kea, Hawaii, USA, Altitud 3,052 m (10,013 ft)
As it turns out, that’s because it’s one-of-a-kind.
Most objects in the Solar System – including all of the planets – orbit the Sun in the same direction: anticlockwise, or prograde. Of the thousands and thousands of asteroids and comets and planetesimals and planets and moons, only 95 are known to orbit the Sun clockwise, or retrograde. This makes them pretty rare.
Not only does 2015 BZ509 (affectionately nicknamed Bee-Zed by some astronomers) orbit the Sun clockwise, it’s the only known retrograde object to share an orbit with a planet.
Bee-Zed is co-orbital with Jupiter on a 1:1 resonance, which means it orbits the Sun at more or less the same speed as the planet – just in the opposite direction.
Jupiter shares its orbital space with around 6,000 known asteroids, most of which travel in the same direction. There are a few other retrograde asteroids, but none with the co-orbital resonance the planet shares with Bee-Zed.
And its delicately balanced gravitational relationship with both the Sun and Jupiter allows it to maintain its eccentric orbit, which it has been in for at least a million years, according to a paper [https://www.nature.com/articles/nature22029Nature] released last year.
The two bodies pass within just 176 million kilometres (109 million miles) of each other twice an orbit; Jupiter tugs on the asteroid, which prevents it from tumbling Sun-ward; and the Sun tugs it back, preventing it from falling into Jupiter.
“How the asteroid came to move in this way while sharing Jupiter’s orbit has until now been a mystery,” explained astronomer and cosmologist Fathi Namouni of the Observatoire de la Côte d’Azur in France.
“If 2015 BZ509 were a native of our system, it should have had the same original direction as all of the other planets and asteroids, inherited from the cloud of gas and dust that formed them.”
Namouni and astronomer Helena Morais of the Universidade Estadual Paulista, Brazil, ran computer simulations to see how far back Bee-Zed’s orbital stability could be traced.
They found that it went all the way back to the birth of the Solar System, 4.5 billion years ago – and that, all else remaining as is (it won’t, because the Sun is going to die), it could maintain that orbit for 43 billion years.
U Arizona Large Binocular Telescope, Mount Graham, Arizona, USA, Altitude 3,221 m (10,568 ft). The Large Binocular Telescope Interferometer, or LBTI, is a ground-based instrument connecting two 8-meter class telescopes on Mount Graham in Arizona to form the largest single-mount telescope in the world. The interferometer is designed to detect and study stars and planets outside our solar system. Image credit: NASA/JPL-Caltech.
“Asteroid immigration from other star systems occurs because the Sun initially formed in a tightly-packed star cluster, where every star had its own system of planets and asteroids,” Morais said.
“The close proximity of the stars, aided by the gravitational forces of the planets, help these systems attract, remove and capture asteroids from one another.”
If Bee-Zed always orbited this way, then it could not have formed alongside all the objects with a prograde orbit. This means that it had to have come from elsewhere.
So, are other retrograde objects in the Solar System also immigrants from other star systems? Not necessarily.
When Wiegert and team found that Bee-Zed’s orbit had been stable for at least a million years, that was two orders of magnitude longer than other retrograde resonant asteroids that have been temporarily captured by Jupiter and Saturn.
This means that Bee-Zed’s origin may be different from most retrograde asteroids.
But it also may mean that there are other interstellar asteroids currently present in the Solar System.
Identifying these, and studying Bee-Zed in greater detail, could help provide clues about the early Solar System, as far back as the stellar nursery in which our Sun was born.
Scientists have found a new lineage of microbes in the famously hot and acidic spring waters of Yellowstone National Park in the US, a discovery that promises to teach us more about the origins of life on our planet.
These single-cell organisms, from the archaea domain of life, seem to thrive in the thermal springs of Yellowstone where iron oxide is the main mineral.
Because the surface of Mars is made up of the same sort of materials, the researchers have named the lineage Marsarchaeota.
The conditions inside the springs of Yellowstone are thought to match the conditions on the early Earth, and that’s why these Marsarchaeota microbes can be so helpful – they can show us how organisms sparked into life, and what role iron oxide may have played.
“The discovery of archaeal lineages is critical to our understanding of the universal tree of life and evolutionary history of Earth,” write the researchers [Nature Microbiology].
“The broad distribution of Marsarchaeota in geothermal, microaerobic iron oxide mats suggests that similar habitat types probably played an important role in the evolution of archaea.”
Using a variety of techniques – including microscopic analysis and genome sequencing – the team studied microbial mats in Yellowstone Park springs that are about as acidic as grapefruit juice.
Two groups of Marsarchaeota were identified, one living in temperatures above 50 degrees Celsius (122 degrees Fahrenheit) and the other living in temperatures between 60 and 80 degrees Celsius (140 to 176 degrees Fahrenheit).
Samples were taken from across Yellowstone Park, with these archaea lineages sometimes making up as much as half the organisms inside a single microbial mat.
The mats themselves have been turned red by the iron oxide, which also slows the passage of water across the top of the mats. Oxygen is captured from the atmosphere and supplied to the Marsarchaoeta as water trickles over them – though the microbes are very deep, they only require low levels of oxygen.
“Physics comes together with chemistry and microbiology,” says senior researcher William Inskeep, from Montana State University. “It’s like a sweet spot of conditions that this group of organisms likes.”
By adding these archaea to “the universal tree of life”, we can get a better idea of the ancient organisms that first sprung up on the planet, and maybe then answer the broader question of how they evolved into multi-celled eukaryotes – animals and plants.
One idea is that these Marsarchaeota might be involved in converting iron into a simpler form. They don’t produce iron oxide themselves, as other microbes do.
“Iron cycling has been implicated as being extremely important in early Earth conditions,” says Inskeep.
More close observation will be required to figure out how this particular type of microbe can flourish in these conditions, and what its role might have been before any other type of life appeared on Earth.
And the potential benefits to science don’t end there. Further down the line these microorganisms could give us more clues about how life is potentially surviving on Mars, as well as some of the fundamentals about biology at higher temperatures.
“Knowing about this new group of archaea provides additional pieces of the puzzle for understanding high-temperature biology,” says Inskeep.
“That could be important in industry and molecular biology.”
And what precisely about the origin of life is this supposed to point to? The Mars/iron association is hardly more than wishful association. There is some interesting science relative to archaea and such, but hardly any solution to any of the intractable naturalistic conjectures being offered as serious solutions to naturalistic origin of life. The prospect of offering any serious contribution to the origin of life is overly optimistic faith in an ideology that has no viable solutions.
Artist’s impression of a rotating neutron star. (Pitris/iStock)
Astronomers have discovered a record-breaking star system. It’s called IGR J17062-6143, and it’s a very compact binary, where one of the stars is a rapidly spinning, superdense neutron star called an X-ray pulsar.
The two stars take just 38 minutes to orbit each other. That’s the fastest orbital period of any X-ray pulsar binary ever observed.
IGR J17062-6143 (or J17062 for short) was only discovered in 2006; it’s very low mass, and very faint, and around 7.3 kiloparsecs, or 23,809 light-years, away.
It’s been studied fairly extensively, but finding out more about it required some pretty up-to-date technology – NASA’s Neutron star Interior Composition Explorer (NICER), an X-ray detection instrument installed on the International Space Station in June 2017.
NASA NICER on the ISS
NASA/NICER
Previous research had revealed an accretion disc associated with the binary, and that one of the stars was a pulsar, but a 20-minute 2008 observation using NASA’s Rossi X-Ray Timing Explorer could only set a lower limit for the binary’s orbital period.
NASA/ROSSI
Neutron stars are also extremely hot, and shine extremely brightly. However, because they’re so small, they’re difficult for us to see – except in X-ray. They can also spin incredibly fast, which creates an electric field that accelerates electrons away from the poles, creating relativistic radiation jets. If this beam passes between us and the pulsar, we can see it flash, or “pulse”, like a cosmic lighthouse.
In the case of binary X-ray pulsars, these jets are fed by the matter stolen from the donor star. This material falls to the surface of the pulsar, where it travels along its strong magnetic field lines to the poles.
It was by observing these X-ray jets that the 2008 observation led to the discovery – the J17062 pulsar was rotating 163 times per second, nearly 9,800 revolutions per minute.
NICER has been able to observe the system for a lot longer – over 7 hours of observing time taken over 5.3 days in August 2017. This has allowed researchers to obtain a lot more detailed information.
As well as the 38-minute orbital period, researchers were able to ascertain that the two stars are separated by a distance of just 300,000 kilometres (186,000 miles) – less than the distance that separates Earth and the Moon.
These two factors, and analysis of the spectra produced by the binary, has led the research team on the new paper to the conclusion that the pulsar’s companion star is a very low-mass, low-hydrogen white dwarf, only around 1.5 percent the mass of the Sun. “It’s not possible for a hydrogen-rich star, like our Sun, to be the pulsar’s companion,” said lead researcher Tod Strohmayer, an astrophysicist at NASA Goddard.
“You can’t fit a star like that into an orbit so small.”
The pulsar, by comparison, is around 1.4 times the mass of the Sun, but much, much smaller. Neutron stars – of which pulsars are a subset – are the collapsed cores of stars below around three times the mass of the Sun, in the final stage of their life cycle. They’re usually only around 10-20 kilometres in diameter.
Because they’re so massive, though, neutron stars have a pretty strong gravitational pull – hence the accretion disc, as the J17062 pulsar pulls material from the white dwarf, the binary’s ‘donor star’. That high mass imbalance also means that the central point of the orbit – circular, as the team discovered – is much closer to the pulsar, just 3,000 kilometres (1,900 miles) from it. It’s so close that the white dwarf almost seems to be orbiting a stationary star; but, although faint, it does exert a gravitational pull on the pulsar.
“The distance between us and the pulsar is not constant,” Strohmayer said. “It’s varying by this orbital motion. When the pulsar is closer, the X-ray emission takes a little less time to reach us than when it’s further away.” “This time delay is small, only about 8 milliseconds for J17062’s orbit, but it’s well within the capabilities of a sensitive pulsar machine like NICER.”
NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.
Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.
Black holes could be making cataclysmic collisions across the Universe every few minutes. Unfortunately, the aftermath is too faint to alert our current detection technology.
But a clever new technique could allow us to “hear” these collisions by finding their signals in the background static that LIGO-Virgo’s detectors are picking up all the time.
Even though we humans can’t hear any sounds coming from space, the gravitational wave signal of two black holes or neutron stars colliding can be translated into a sound wave.
This has been done for the six confirmed gravitational wave signals picked up since that first groundbreaking detection in 2015.
But these events are much more frequent than we have detected to date, according to Eric Thrane and Rory Smith of the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) and Monash University.
Both of these researchers participated in that first discovery, as well as last year’s jaw-dropping neutron star collision.
The first optical image of a gravitational wave source was taken by a team led by Ryan Foley of UC Santa Cruz using the Swope Telescope at the Carnegie Institution’s Las Campanas Observatory in Chile. This image of Swope Supernova Survey 2017a (SSS17a, indicated by arrow) shows the light emitted from the cataclysmic merger of two neutron stars. (Image credit: 1M2H Team/UC Santa Cruz & Carnegie Observatories/Ryan Foley)
Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile
A neutron star forms when a massive star runs out of fuel and explodes as a supernova, throwing off its outer layers and leaving behind a collapsed core composed almost entirely of neutrons. Neutrons are the uncharged particles in the nucleus of an atom, where they are bound together with positively charged protons. In a neutron star, they are packed together just as densely as in the nucleus of an atom, resulting in an object with one to three times the mass of our sun but only about 12 miles wide.
“Basically, a neutron star is a gigantic atom with the mass of the sun and the size of a city like San Francisco or Manhattan,” said Foley, an assistant professor of astronomy and astrophysics at UC Santa Cruz.
These objects are so dense, a cup of neutron star material would weigh as much as Mount Everest, and a teaspoon would weigh a billion tons. It’s as dense as matter can get without collapsing into a black hole.
THE MERGER
Like other stars, neutron stars sometimes occur in pairs, orbiting each other and gradually spiraling inward. Eventually, they come together in a catastrophic merger that distorts space and time (creating gravitational waves) and emits a brilliant flare of electromagnetic radiation, including visible, infrared, and ultraviolet light, x-rays, gamma rays, and radio waves. Merging black holes also create gravitational waves, but there’s nothing to be seen because no light can escape from a black hole.
Foley’s team was the first to observe the light from a neutron star merger that took place on August 17, 2017, and was detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO).
VIRGO Gravitational Wave interferometer, near Pisa, Italy
Caltech/MIT Advanced aLigo Hanford, WA, USA installation
Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA
Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project
Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib
ESA/eLISA the future of gravitational wave research
Skymap showing how adding Virgo to LIGO helps in reducing the size of the source-likely region in the sky. (Credit: Giuseppe Greco (Virgo Urbino group)
Now, for the first time, scientists can study both the gravitational waves (ripples in the fabric of space-time), and the radiation emitted from the violent merger of the densest objects in the universe.
The UC Santa Cruz team found SSS17a by comparing a new image of the galaxy N4993 (right) with images taken four months earlier by the Hubble Space Telescope (left). The arrows indicate where SSS17a was absent from the Hubble image and visible in the new image from the Swope Telescope. (Image credits: Left, Hubble/STScI; Right, 1M2H Team/UC Santa Cruz & Carnegie Observatories/Ryan Foley)
It’s that combination of data, and all that can be learned from it, that has astronomers and physicists so excited. The observations of this one event are keeping hundreds of scientists busy exploring its implications for everything from fundamental physics and cosmology to the origins of gold and other heavy elements.
A small team of UC Santa Cruz astronomers were the first team to observe light from two neutron stars merging in August. The implications are huge.
ALL THE GOLD IN THE UNIVERSE
It turns out that the origins of the heaviest elements, such as gold, platinum, uranium—pretty much everything heavier than iron—has been an enduring conundrum. All the lighter elements have well-explained origins in the nuclear fusion reactions that make stars shine or in the explosions of stars (supernovae). Initially, astrophysicists thought supernovae could account for the heavy elements, too, but there have always been problems with that theory, says Enrico Ramirez-Ruiz, professor and chair of astronomy and astrophysics at UC Santa Cruz.
The violent merger of two neutron stars is thought to involve three main energy-transfer processes, shown in this diagram, that give rise to the different types of radiation seen by astronomers, including a gamma-ray burst and a kilonova explosion seen in visible light. (Image credit: Murguia-Berthier et al., Science)
A theoretical astrophysicist, Ramirez-Ruiz has been a leading proponent of the idea that neutron star mergers are the source of the heavy elements. Building a heavy atomic nucleus means adding a lot of neutrons to it. This process is called rapid neutron capture, or the r-process, and it requires some of the most extreme conditions in the universe: extreme temperatures, extreme densities, and a massive flow of neutrons. A neutron star merger fits the bill.
Ramirez-Ruiz and other theoretical astrophysicists use supercomputers to simulate the physics of extreme events like supernovae and neutron star mergers. This work always goes hand in hand with observational astronomy. Theoretical predictions tell observers what signatures to look for to identify these events, and observations tell theorists if they got the physics right or if they need to tweak their models. The observations by Foley and others of the neutron star merger now known as SSS17a are giving theorists, for the first time, a full set of observational data to compare with their theoretical models.
According to Ramirez-Ruiz, the observations support the theory that neutron star mergers can account for all the gold in the universe, as well as about half of all the other elements heavier than iron.
RIPPLES IN THE FABRIC OF SPACE-TIME
Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity, but until recently they were impossible to observe. LIGO’s extraordinarily sensitive detectors achieved the first direct detection of gravitational waves, from the collision of two black holes, in 2015. Gravitational waves are created by any massive accelerating object, but the strongest waves (and the only ones we have any chance of detecting) are produced by the most extreme phenomena.
Two massive compact objects—such as black holes, neutron stars, or white dwarfs—orbiting around each other faster and faster as they draw closer together are just the kind of system that should radiate strong gravitational waves. Like ripples spreading in a pond, the waves get smaller as they spread outward from the source. By the time they reached Earth, the ripples detected by LIGO caused distortions of space-time thousands of times smaller than the nucleus of an atom.
The rarefied signals recorded by LIGO’s detectors not only prove the existence of gravitational waves, they also provide crucial information about the events that produced them. Combined with the telescope observations of the neutron star merger, it’s an incredibly rich set of data.
LIGO can tell scientists the masses of the merging objects and the mass of the new object created in the merger, which reveals whether the merger produced another neutron star or a more massive object that collapsed into a black hole. To calculate how much mass was ejected in the explosion, and how much mass was converted to energy, scientists also need the optical observations from telescopes. That’s especially important for quantifying the nucleosynthesis of heavy elements during the merger.
LIGO can also provide a measure of the distance to the merging neutron stars, which can now be compared with the distance measurement based on the light from the merger. That’s important to cosmologists studying the expansion of the universe, because the two measurements are based on different fundamental forces (gravity and electromagnetism), giving completely independent results.
“This is a huge step forward in astronomy,” Foley said. “Having done it once, we now know we can do it again, and it opens up a whole new world of what we call ‘multi-messenger’ astronomy, viewing the universe through different fundamental forces.”
IN THIS REPORT
Neutron stars
A team from UC Santa Cruz was the first to observe the light from a neutron star merger that took place on August 17, 2017 and was detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO)
Graduate students and post-doctoral scholars at UC Santa Cruz played key roles in the dramatic discovery and analysis of colliding neutron stars.Astronomer Ryan Foley leads a team of young graduate students and postdoctoral scholars who have pulled off an extraordinary coup. Following up on the detection of gravitational waves from the violent merger of two neutron stars, Foley’s team was the first to find the source with a telescope and take images of the light from this cataclysmic event. In so doing, they beat much larger and more senior teams with much more powerful telescopes at their disposal.
“We’re sort of the scrappy young upstarts who worked hard and got the job done,” said Foley, an untenured assistant professor of astronomy and astrophysics at UC Santa Cruz.
David Coulter, graduate student
The discovery on August 17, 2017, has been a scientific bonanza, yielding over 100 scientific papers from numerous teams investigating the new observations. Foley’s team is publishing seven papers, each of which has a graduate student or postdoc as the first author.
“I think it speaks to Ryan’s generosity and how seriously he takes his role as a mentor that he is not putting himself front and center, but has gone out of his way to highlight the roles played by his students and postdocs,” said Enrico Ramirez-Ruiz, professor and chair of astronomy and astrophysics at UC Santa Cruz and the most senior member of Foley’s team.
“Our team is by far the youngest and most diverse of all of the teams involved in the follow-up observations of this neutron star merger,” Ramirez-Ruiz added.
Charles Kilpatrick, postdoctoral scholar
Charles Kilpatrick, a 29-year-old postdoctoral scholar, was the first person in the world to see an image of the light from colliding neutron stars. He was sitting in an office at UC Santa Cruz, working with first-year graduate student Cesar Rojas-Bravo to process image data as it came in from the Swope Telescope in Chile. To see if the Swope images showed anything new, he had also downloaded “template” images taken in the past of the same galaxies the team was searching.
Ariadna Murguia-Berthier, graduate student
“In one image I saw something there that was not in the template image,” Kilpatrick said. “It took me a while to realize the ramifications of what I was seeing. This opens up so much new science, it really marks the beginning of something that will continue to be studied for years down the road.”
At the time, Foley and most of the others in his team were at a meeting in Copenhagen. When they found out about the gravitational wave detection, they quickly got together to plan their search strategy. From Copenhagen, the team sent instructions to the telescope operators in Chile telling them where to point the telescope. Graduate student David Coulter played a key role in prioritizing the galaxies they would search to find the source, and he is the first author of the discovery paper published in Science.
Matthew Siebert, graduate student
“It’s still a little unreal when I think about what we’ve accomplished,” Coulter said. “For me, despite the euphoria of recognizing what we were seeing at the moment, we were all incredibly focused on the task at hand. Only afterward did the significance really sink in.”
Just as Coulter finished writing his paper about the discovery, his wife went into labor, giving birth to a baby girl on September 30. “I was doing revisions to the paper at the hospital,” he said.
It’s been a wild ride for the whole team, first in the rush to find the source, and then under pressure to quickly analyze the data and write up their findings for publication. “It was really an all-hands-on-deck moment when we all had to pull together and work quickly to exploit this opportunity,” said Kilpatrick, who is first author of a paper comparing the observations with theoretical models.
César Rojas Bravo, graduate student
Graduate student Matthew Siebert led a paper analyzing the unusual properties of the light emitted by the merger. Astronomers have observed thousands of supernovae (exploding stars) and other “transients” that appear suddenly in the sky and then fade away, but never before have they observed anything that looks like this neutron star merger. Siebert’s paper concluded that there is only a one in 100,000 chance that the transient they observed is not related to the gravitational waves.
Ariadna Murguia-Berthier, a graduate student working with Ramirez-Ruiz, is first author of a paper synthesizing data from a range of sources to provide a coherent theoretical framework for understanding the observations.
Another aspect of the discovery of great interest to astronomers is the nature of the galaxy and the galactic environment in which the merger occurred. Postdoctoral scholar Yen-Chen Pan led a paper analyzing the properties of the host galaxy. Enia Xhakaj, a new graduate student who had just joined the group in August, got the opportunity to help with the analysis and be a coauthor on the paper.
Yen-Chen Pan, postdoctoral scholar
“There are so many interesting things to learn from this,” Foley said. “It’s a great experience for all of us to be part of such an important discovery.”
Abbott et al., Nature, A gravitational-wave standard siren measurement of the Hubble constant (The LIGO Scientific Collaboration and The Virgo Collaboration, The 1M2H Collaboration, The Dark Energy Camera GW-EM Collaboration and the DES Collaboration, The DLT40 Collaboration, The Las Cumbres Observatory Collaboration, The VINROUGE Collaboration & The MASTER Collaboration)
Writing: Tim Stephens
Video: Nick Gonzales
Photos: Carolyn Lagattuta
Header image: Illustration by Robin Dienel courtesy of the Carnegie Institution for Science
Design and development: Rob Knight
Project managers: Sherry Main, Scott Hernandez-Jason, Tim Stephens
NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet
Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet
Noted in the video but not in the article:
NASA/Chandra Telescope
NASA/SWIFT Telescope
NRAO/Karl V Jansky VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA
CTIO PROMPT telescope telescope built by the University of North Carolina at Chapel Hill at Cerro Tololo Inter-American Observatory in Chilein the Chilean Andes.
Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA
The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.
Lick Observatory’s Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building
Search for extraterrestrial intelligence expands at Lick Observatory
New instrument scans the sky for pulses of infrared light
March 23, 2015
By Hilary Lebow
The NIROSETI instrument saw first light on the Nickel 1-meter Telescope at Lick Observatory on March 15, 2015. (Photo by Laurie Hatch) UCSC Lick Nickel telescope
Astronomers are expanding the search for extraterrestrial intelligence into a new realm with detectors tuned to infrared light at UC’s Lick Observatory. A new instrument, called NIROSETI, will soon scour the sky for messages from other worlds.
“Infrared light would be an excellent means of interstellar communication,” said Shelley Wright, an assistant professor of physics at UC San Diego who led the development of the new instrument while at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics.
Wright worked on an earlier SETI project at Lick Observatory as a UC Santa Cruz undergraduate, when she built an optical instrument designed by UC Berkeley researchers. The infrared project takes advantage of new technology not available for that first optical search.
Infrared light would be a good way for extraterrestrials to get our attention here on Earth, since pulses from a powerful infrared laser could outshine a star, if only for a billionth of a second. Interstellar gas and dust is almost transparent to near infrared, so these signals can be seen from great distances. It also takes less energy to send information using infrared signals than with visible light.
UCSC alumna Shelley Wright, now an assistant professor of physics at UC San Diego, discusses the dichroic filter of the NIROSETI instrument. (Photo by Laurie Hatch)
Frank Drake, professor emeritus of astronomy and astrophysics at UC Santa Cruz and director emeritus of the SETI Institute, said there are several additional advantages to a search in the infrared realm.
“The signals are so strong that we only need a small telescope to receive them. Smaller telescopes can offer more observational time, and that is good because we need to search many stars for a chance of success,” said Drake.
The only downside is that extraterrestrials would need to be transmitting their signals in our direction, Drake said, though he sees this as a positive side to that limitation. “If we get a signal from someone who’s aiming for us, it could mean there’s altruism in the universe. I like that idea. If they want to be friendly, that’s who we will find.”
Scientists have searched the skies for radio signals for more than 50 years and expanded their search into the optical realm more than a decade ago. The idea of searching in the infrared is not a new one, but instruments capable of capturing pulses of infrared light only recently became available.
“We had to wait,” Wright said. “I spent eight years waiting and watching as new technology emerged.”
Now that technology has caught up, the search will extend to stars thousands of light years away, rather than just hundreds. NIROSETI, or Near-Infrared Optical Search for Extraterrestrial Intelligence, could also uncover new information about the physical universe.
“This is the first time Earthlings have looked at the universe at infrared wavelengths with nanosecond time scales,” said Dan Werthimer, UC Berkeley SETI Project Director. “The instrument could discover new astrophysical phenomena, or perhaps answer the question of whether we are alone.”
NIROSETI will also gather more information than previous optical detectors by recording levels of light over time so that patterns can be analyzed for potential signs of other civilizations.
“Searching for intelligent life in the universe is both thrilling and somewhat unorthodox,” said Claire Max, director of UC Observatories and professor of astronomy and astrophysics at UC Santa Cruz. “Lick Observatory has already been the site of several previous SETI searches, so this is a very exciting addition to the current research taking place.”
NIROSETI will be fully operational by early summer and will scan the skies several times a week on the Nickel 1-meter telescope at Lick Observatory, located on Mt. Hamilton east of San Jose.
The NIROSETI team also includes Geoffrey Marcy and Andrew Siemion from UC Berkeley; Patrick Dorval, a Dunlap undergraduate, and Elliot Meyer, a Dunlap graduate student; and Richard Treffers of Starman Systems. Funding for the project comes from the generous support of Bill and Susan Bloomfield.
When two black holes or neutron stars collide, the event is so massive and disruptive that it sends gravitational waves rippling out across the fabric of space-time.
Although predicted by Einstein’s theory of general relativity in 1915, it wasn’t until 100 years later that we were able to develop instrumentation sensitive enough to detect these ripples.
The technology is still in its infancy and is being refined over time. This means, potentially, that there is a lot we still can’t detect.
Every year, the researchers say, there are over 100,000 gravitational wave events that are too faint for the interferometers of the LIGO-Virgo collaboration to detect unambiguously.
These are caused by smaller black hole collisions, and collisions much farther away. Rather than showing up as individual signal spikes, their signals resolve into a sort of “hum”.
Researchers have been trying to find this hum for years – and now Thrane, Smith and their team believe they may have developed a method sensitive enough to detect it among the gravitational wave background static picked up by the interferometers.
“Measuring the gravitational-wave background will allow us to study populations of black holes at vast distances,” Thrane said.
“Someday, the technique may enable us to see gravitational waves from the Big Bang, hidden behind gravitational waves from black holes and neutron stars.”
The team has developed an algorithm that can comb through the LIGO-Virgo static data and pick out the signals of the black hole collisions – when converted to audio, it’s an upsweep of sound that ends in a sort of loud “BLOOP.”
“It’s the same thing your brain does when your car radio goes out of reception and goes to static,” Smith told the Sydney Morning Herald.
“Little bits and pieces of radio stations still come through – but your brain is able to put them together and work out what song is playing.”
To test it, they created simulations of black hole collisions, then had their algorithm try to pick them out of background static.
They found that it wasn’t fooled by artefacts such as background glitches, and was reliably able to pick out unpredictable signals.
It has yet to be applied to real data, but the researchers are confident it will work, especially run on a powerful new supercomputer at Swinburne University.
OzSTAR, with a peak performance of 1.2 petaflops, will be used to sort through the vast amounts of data being generated by gravitational wave detectors, looking for black hole and neutron star mergers in real-time.
“It gives us a taste of the universe at its most extreme,” Matthew Bailes, director of OzGrav, told the ABC.
“It’s when you’ve sort of set the laws of physics to ‘stun’, and to a physicist that is an exciting place to probe.”
The team’s research has been accepted into the journal Physical Review X.
Monash University (/ˈmɒnæʃ/) is an Australian public research university based in Melbourne, Australia. Founded in 1958, it is the second oldest university in the State of Victoria. Monash is a member of Australia’s Group of Eight and the ASAIHL, and is the only Australian member of the influential M8 Alliance of Academic Health Centers, Universities and National Academies. Monash is one of two Australian universities to be ranked in the The École des Mines de Paris (Mines ParisTech) ranking on the basis of the number of alumni listed among CEOs in the 500 largest worldwide companies.[6] Monash is in the top 20% in teaching, top 10% in international outlook, top 20% in industry income and top 10% in research in the world in 2016.[7]
Monash enrolls approximately 47,000 undergraduate and 20,000 graduate students,[8] It also has more applicants than any university in the state of Victoria.
Monash is home to major research facilities, including the Australian Synchrotron, the Monash Science Technology Research and Innovation Precinct (STRIP), the Australian Stem Cell Centre, 100 research centres[9] and 17 co-operative research centres. In 2011, its total revenue was over $2.1 billion, with external research income around $282 million.[10]
The university has a number of centres, five of which are in Victoria (Clayton, Caulfield, Berwick, Peninsula, and Parkville), one in Malaysia.[11] Monash also has a research and teaching centre in Prato, Italy,[12] a graduate research school in Mumbai, India[13] and a graduate school in Jiangsu Province, China.[14] Since December 2011, Monash has had a global alliance with the University of Warwick in the United Kingdom.[15] Monash University courses are also delivered at other locations, including South Africa.
The Clayton campus contains the Robert Blackwood Hall, named after the university’s founding Chancellor Sir Robert Blackwood and designed by Sir Roy Grounds.[16]
In 2014, the University ceded its Gippsland campus to Federation University.[17] On 7 March 2016, Monash announced that it would be closing the Berwick campus by 2018.
Scientists have just performed the world’s most precisely controlled chemical reaction, sticking together just two atoms from elements that wouldn’t normally form a molecule.
The two elements – sodium and caesium – produced an interesting alloy-like molecule. On top of that, this method of creation could set the way of making just the kind of materials we might need in future technology.
A team of Harvard University scientists used laser ‘tweezers’ to manipulate individual atoms of the two alkali metals into close proximity, and provided a photon to help them bond into a single molecule.
Chemical reactions are usually hit-and-miss affairs, where vast numbers of atoms are thrown together under the right conditions, and probability does the rest.
This ‘stochastic’ method of chemical reactions is all well and good if the combination of elements are a decent match. But when scientists want a really exotic pairing, they need to get creative.
Sodium (Na) and caesium (Cs) are both found in the same group on the periodic table – as you may remember from high school chemistry, it means they tend to have similar reactive properties.
Periodic table Sept 2017. Wikipedia
They also don’t tend to bump into each other and easily bond as a molecule.
Which is really a shame – the polarised electrical properties of a molecule of NaCs would make it super useful for storing quantum ‘qubit’ states of superposition that can also interact easily with other components.
This all-in-one combination of qubit storage plus interaction is something desperately needed in future technology.
“The direction of quantum information processing is one of the things we’re excited about,” says lead researcher and chemist Kang-Kuen Ni.
Improbable doesn’t mean impossible, though: if these two atoms happen to be close enough with the right energy, a connection can form.
To achieve this perfect mix of energy and timing, the researchers held single atoms in overlapping magneto-optical traps and pelted them with photons to cool them down to a fraction of a degree above absolute zero.
Meanwhile, they used a pair of lasers tuned to create an electrical effect, causing each atom to move towards each laser’s focus, as if they were pulled into two sci-fi tractor beams.
Nearby, the two atoms can collide easily. This still doesn’t necessarily guarantee they’ll bond, given the need to conserve the right momentum and energy levels.
It’s a tricky juggle of conditions, one the researchers managed using the right laser pulses.
The end result is a brief flicker of a bond between two atoms in the same quantum state, providing the researchers with details on what’s happening on an extremely fine level.
Ni says the next step would be to create longer lasting molecules by combining them while in a ground state, rather than an excited one.
“I think that a lot of scientists will follow, now that we have shown what is possible,” says Ni.
The ultimate goal would be to tailor the creation of far more complex molecules, making use not only of their classical shapes but creating tiny quantum components for the next generation of computing.
And for this kind of construction, nothing can be left to sheer chance.
“The experimental demonstration represents for the first time that a chemical reaction process is deterministically controlled,” Jun Ye of the US National Institute of Standards and Technology told David Bradley from Chemistryworld.
Though Ye wasn’t part of the study, he expressed excitement over the results.
“Control of molecular interactions, including reaction, at the most fundamental level has been a long-standing goal in physical science.”
Harvard is the oldest institution of higher education in the United States, established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. It was named after the College’s first benefactor, the young minister John Harvard of Charlestown, who upon his death in 1638 left his library and half his estate to the institution. A statue of John Harvard stands today in front of University Hall in Harvard Yard, and is perhaps the University’s best known landmark.
Harvard University has 12 degree-granting Schools in addition to the Radcliffe Institute for Advanced Study. The University has grown from nine students with a single master to an enrollment of more than 20,000 degree candidates including undergraduate, graduate, and professional students. There are more than 360,000 living alumni in the U.S. and over 190 other countries.
In the summer of 1935, the physicists Albert Einstein and Erwin Schrödinger engaged in a rich, multifaceted and sometimes fretful correspondence about the implications of the new theory of quantum mechanics.
The focus of their worry was what Schrödinger later dubbed entanglement: the inability to describe two quantum systems or particles independently, after they have interacted.
Until his death, Einstein remained convinced that entanglement showed how quantum mechanics was incomplete. Schrödinger thought that entanglement was the defining feature of the new physics, but this didn’t mean that he accepted it lightly.
“I know of course how the hocus pocus works mathematically,” he wrote to Einstein on 13 July 1935. “But I do not like such a theory.”
Schrödinger’s famous cat, suspended between life and death, first appeared in these letters, a byproduct of the struggle to articulate what bothered the pair.
The problem is that entanglement violates how the world ought to work. Information can’t travel faster than the speed of light, for one.
But in a 1935 paper [Physical Review Journals Archive], Einstein and his co-authors showed how entanglement leads to what’s now called quantum nonlocality, the eerie link that appears to exist between entangled particles.
If two quantum systems meet and then separate, even across a distance of thousands of lightyears, it becomes impossible to measure the features of one system (such as its position, momentum and polarity) without instantly steering the other into a corresponding state.
Up to today, most experiments have tested entanglement over spatial gaps.
The assumption is that the ‘nonlocal’ part of quantum nonlocality refers to the entanglement of properties across space. But what if entanglement also occurs across time? Is there such a thing as temporal nonlocality?
The answer, as it turns out, is yes.
Just when you thought quantum mechanics couldn’t get any weirder, a team of physicists at the Hebrew University of Jerusalem reported in 2013 that they had successfully entangled photons that never coexisted.
Previous experiments involving a technique called ‘entanglement swapping’ had already showed quantum correlations across time, by delaying the measurement of one of the coexisting entangled particles; but Eli Megidish and his collaborators were the first to show entanglement between photons whose lifespans did not overlap at all.
Here’s how they did it.
First, they created an entangled pair of photons, ‘1-2’ (step I in the diagram below). Soon after, they measured the polarisation of photon 1 (a property describing the direction of light’s oscillation) – thus ‘killing’ it (step II).
(Provided)
Photon 2 was sent on a wild goose chase while a new entangled pair, ‘3-4’, was created (step III). Photon 3 was then measured along with the itinerant photon 2 in such a way that the entanglement relation was ‘swapped’ from the old pairs (‘1-2’ and ‘3-4’) onto the new ‘2-3’ combo (step IV).
Some time later (step V), the polarisation of the lone survivor, photon 4, is measured, and the results are compared with those of the long-dead photon 1 (back at step II).
The upshot? The data revealed the existence of quantum correlations between ‘temporally nonlocal’ photons 1 and 4. That is, entanglement can occur across two quantum systems that never coexisted.
What on Earth can this mean? Prima facie, it seems as troubling as saying that the polarity of starlight in the far-distant past – say, greater than twice Earth’s lifetime – nevertheless influenced the polarity of starlight falling through your amateur telescope this winter.
Even more bizarrely: maybe it implies that the measurements carried out by your eye upon starlight falling through your telescope this winter somehow dictated the polarity of photons more than 9 billion years old.
Lest this scenario strike you as too outlandish, Megidish and his colleagues can’t resist speculating on possible and rather spooky interpretations of their results.
Perhaps the measurement of photon 1’s polarisation at step II somehow steers the future polarisation of 4, or the measurement of photon 4’s polarisation at step V somehow rewrites the past polarisation state of photon 1.
In both forward and backward directions, quantum correlations span the causal void between the death of one photon and the birth of the other.
Just a spoonful of relativity helps the spookiness go down, though.
In developing his theory of special relativity, Einstein deposed the concept of simultaneity from its Newtonian pedestal.
As a consequence, simultaneity went from being an absolute property to being a relative one. There is no single timekeeper for the Universe; precisely when something is occurring depends on your precise location relative to what you are observing, known as your frame of reference.
So the key to avoiding strange causal behaviour (steering the future or rewriting the past) in instances of temporal separation is to accept that calling events ‘simultaneous’ carries little metaphysical weight.
It is only a frame-specific property, a choice among many alternative but equally viable ones – a matter of convention, or record-keeping.
The lesson carries over directly to both spatial and temporal quantum nonlocality.
Mysteries regarding entangled pairs of particles amount to disagreements about labelling, brought about by relativity.
Einstein showed that no sequence of events can be metaphysically privileged – can be considered more real – than any other. Only by accepting this insight can one make headway on such quantum puzzles.
The various frames of reference in the Hebrew University experiment (the lab’s frame, photon 1’s frame, photon 4’s frame, and so on) have their own ‘historians’, so to speak.
While these historians will disagree about how things went down, not one of them can claim a corner on truth. A different sequence of events unfolds within each one, according to that spatiotemporal point of view.
Clearly, then, any attempt at assigning frame-specific properties generally, or tying general properties to one particular frame, will cause disputes among the historians.
But here’s the thing: while there might be legitimate disagreement about which properties should be assigned to which particles and when, there shouldn’t be disagreement about the very existence of these properties, particles, and events.
These findings drive yet another wedge between our beloved classical intuitions and the empirical realities of quantum mechanics.
As was true for Schrödinger and his contemporaries, scientific progress is going to involve investigating the limitations of certain metaphysical views.
Schrödinger’s cat, half-alive and half-dead, was created to illustrate how the entanglement of systems leads to macroscopic phenomena that defy our usual understanding of the relations between objects and their properties: an organism such as a cat is either dead or alive. No middle ground there.
Most contemporary philosophical accounts of the relationship between objects and their properties embrace entanglement solely from the perspective of spatial nonlocality.
But there’s still significant work to be done on incorporating temporal nonlocality – not only in object-property discussions, but also in debates over material composition (such as the relation between a lump of clay and the statue it forms), and part-whole relations (such as how a hand relates to a limb, or a limb to a person).
For example, the ‘puzzle’ of how parts fit with an overall whole presumes clear-cut spatial boundaries among underlying components, yet spatial nonlocality cautions against this view. Temporal nonlocality further complicates this picture: how does one describe an entity whose constituent parts are not even coexistent?
Discerning the nature of entanglement might at times be an uncomfortable project. It’s not clear what substantive metaphysics might emerge from scrutiny of fascinating new research by the likes of Megidish and other physicists.
In a letter to Einstein, Schrödinger notes wryly (and deploying an odd metaphor): “One has the feeling that it is precisely the most important statements of the new theory that can really be squeezed into these Spanish boots – but only with difficulty.”
We cannot afford to ignore spatial or temporal nonlocality in future metaphysics: whether or not the boots fit, we’ll have to wear ’em.
Although we use it every day, time is complicated.
When we break it up into small pieces, most people are pretty good at organising time, but everything starts to get a bit wobbly when the timescales get larger.
If you keep zooming out on the history of the Universe, at a certain point time becomes simply incomprehensible for our puny human brains.
The team at Kurzgesagt has just released a new animated video to help explain time, with a timescale that will give you exceptionally weird feelings about the vastness of it all.
“Time makes sense in small pieces,” they begin. “But when you look at large stretches of time, it’s almost impossible to wrap your head around things.”
A lot of amazing things have happened just in 2018 alone, but even the 21st century is starting to get on.
Someone born at the start of the year 2000 (the year The Sims first came out) is now 18 – old enough to buy a drink nearly everywhere in the world.
As the video above explains, the oldest person living today was born closer to Napoleon’s rule over France than to the present day.
Even the advancement of science is mind-boggling – it’s only been 160 years since Charles Darwin’s On the Origin of Species, the modern cornerstone of our understanding of the basics of evolution. Modern physics isn’t that much older.
It gets even weirder when you start thinking about how relatively recent industrialisation was, considering how long human ancestors have been walking around Earth.
And that’s just humans.
Dinosaurs ruled Earth for 27 times as long as all of human history.
We’ll leave Kurzgesagt to explain what happens when you get to the stunningly large time scales of the cosmos in its entirety – and what will happen when it all ceases to exist. Thankfully, they point out it’s not quite the end of the world (or Universe) quite yet.
“The good news is, this is all far far away. The only time that actually matters is now,” they explain in the video.
“No one thought this was possible in solid materials.”
(Emily Edwards, University of Maryland)
One of the ultimate goals of modern physics is to unlock the power of superconductivity, where electricity flows with zero resistance at room temperature.
Progress has been slow, but physicists have just made an unexpected breakthrough. They’ve discovered a superconductor that works in a way no one’s ever seen before – and it opens the door to a whole world of possibilities not considered until now.
In other words, they’ve identified a brand new type of superconductivity.
Why does that matter? Well, when electricity normally flows through a material – for example, the way it travels through wires in the wall when we switch on a light – it’s fast, but surprisingly ineffective.
Electricity is carried by electrons, which bump into atoms in the material along the way, losing some of their energy each time they have one of these collisions. Known as resistance, it’s the reason why electricity grids lose up to 7 percent of their electricity.
But when some materials are chilled to ridiculously cold temperatures, something else happens – the electrons pair up, and begin to flow orderly without resistance.
This is known as superconductivity, and it has incredible potential to revolutionise our world, making our electronics unimaginably more efficient.
The good news is we’ve found the phenomenon in many materials so far. In fact, superconductivity is already used to create the strong magnetic fields in MRI machines and maglev trains.
The bad news is that it currently requires expensive and bulky equipment to keep the superconductors cold enough to achieve this phenomenon – so it remains impractical for broader use.
Now researchers led by the University of Maryland have observed a new type of superconductivity when probing an exotic material at super cool temperatures.
Not only does this type of superconductivity appear in an unexpected material, the phenomenon actually seems to rely on electron interactions that are profoundly different from the pairings we’ve seen to date. And that means we have no idea what kind of potential it might have.
To understand the difference, you need to know that the way electrons interact is dictated by a quantum property called spin.
In regular superconductors, electrons carry a spin referred to as 1/2.
But in this particular material, known as YPtBi, the team found that something else was going on – the electrons appear to have a spin of 3/2.
“No one had really thought that this was possible in solid materials,” explains physicist and senior author Johnpierre Paglione.
“High-spin states in individual atoms are possible but once you put the atoms together in a solid, these states usually break apart and you end up with spin one-half. ”
YPtBi was first discovered to be a superconductor a couple of years ago, and that in itself was a surprise, because the material doesn’t actually fit one of the main criteria – being a relatively good conductor, with a lot of mobile electrons, at normal temperatures.
According to conventional theory, YPtBi would need about a thousand times more mobile electrons in order to become superconducting at temperatures below 0.8 Kelvin.
But when researchers cooled the material down, they saw superconductivity happening anyway.
To figure out what was going on, the latest study looked at the way the material interacted with magnetic fields to get a sense of exactly what was going on inside.
Usually as a material undergoes the transition to a superconductor, it will try to expel any added magnetic field from its surface – but a magnetic field can still enter near, before quickly decaying away. How far they penetrate depends on the nature of the electron pairing happening within.
The team used copper coils to detect changes in YPtBi’s magnetic properties as they changed its temperature.
What they found was odd – as the material warmed up from absolute zero, the amount that a magnetic field could penetrate the material increased linearly instead of exponentially, which is what is normally seen with superconductors.
After running a series of measurements and calculations, the researched concluded that the best explanation for what was going on was that the electrons must have been disguised as particles with higher spin – something that wasn’t even considered as a possibility for a superconductor before.
While this new type of superconductivity still requires incredibly cold temperatures for now, the discovery gives the entire field a whole new direction.
“We used to be confined to pairing with spin one-half particles,” says lead author Hyunsoo Kim.
“But if we start considering higher spin, then the landscape of this superconducting research expands and just gets more interesting.”
This is incredibly early days, and there’s still a lot we have to learn about exactly what’s going on here.
But the fact that we have a brand new type of superconductivity to test and measure, adding a cool new breakthrough to the 100 years of this type of research, is pretty exciting.
“When you have this high-spin pairing, what’s the glue that holds these pairs together?” says Paglione.
“There are some ideas of what might be happening, but fundamental questions remain-which makes it even more fascinating.”
Driven by the pursuit of excellence, the University of Maryland has enjoyed a remarkable rise in accomplishment and reputation over the past two decades. By any measure, Maryland is now one of the nation’s preeminent public research universities and on a path to become one of the world’s best. To fulfill this promise, we must capitalize on our momentum, fully exploit our competitive advantages, and pursue ambitious goals with great discipline and entrepreneurial spirit. This promise is within reach. This strategic plan is our working agenda.
The plan is comprehensive, bold, and action oriented. It sets forth a vision of the University as an institution unmatched in its capacity to attract talent, address the most important issues of our time, and produce the leaders of tomorrow. The plan will guide the investment of our human and material resources as we strengthen our undergraduate and graduate programs and expand research, outreach and partnerships, become a truly international center, and enhance our surrounding community.
Our success will benefit Maryland in the near and long term, strengthen the State’s competitive capacity in a challenging and changing environment and enrich the economic, social and cultural life of the region. We will be a catalyst for progress, the State’s most valuable asset, and an indispensable contributor to the nation’s well-being. Achieving the goals of Transforming Maryland requires broad-based and sustained support from our extended community. We ask our stakeholders to join with us to make the University an institution of world-class quality with world-wide reach and unparalleled impact as it serves the people and the state of Maryland.
Reply