Science is on brink of a materials revolution

Ability to control subatomic ‘spin’ crucial to designing advanced new materials set to change the world



Particle spin occurs in the subatomic world where the laws of quantum physics apply

Seán Duke
Thu Sep 22 2022 - 

Imagine a world where super-strong, super-light, flexible, durable new materials, which don’t exist in nature could be made to order. New breakthroughs in the understanding of “spin”, a characteristic of subatomic particles — like mass and charge — mean we are on the brink of such a revolution.

“The ability to control spin, one of the fundamental properties of particles, is crucial to us being able to design advanced new materials that will change the world,” says Prof Alessandro Lunghi, a physicist at Trinity College Dublin, who heads up a team investigating the phenomenon.

The scientific concepts of particle mass and charge are widely understood and known, but the third property of particles — that of spin — remains mysterious to most. It’s a concept that even many scientists struggle to understand.

Prof Alessandro Lunghi, a physicist at Trinity College Dublin: 'Spin is a very exciting and fragile property of particles and disturbs very easily.'

“This is a tricky one,” says Lunghi. “In the early 1900s when spin was first discovered it was called spin because the mathematical equation describing the behaviour of this property of particles resembled that which also described a classical rigid body rotating — or spinning — on itself.

“The first time that people might hear of spin in school might have been when a teacher asked them to imagine an electron, a tiny ball of electrical charge, spinning on itself, either clockwise or anticlockwise,” he adds.

“We know that this typical description of spin is very far from the reality of what spin is,” Lunghi notes. “It can only be fully understood by getting right down to the nitty gritty of quantum mechanics, but it’s a starting point.”

Particle spin occurs in the subatomic world where the weird laws of quantum physics apply. This is a world of possibilities — but few certainties — where something can be two things at once, or even in two places at the same time.

Different particles have different spin, and this affects whether they are drawn to come together in strong chemical bonds or repel one another. It is also true that spin can be easily disturbed by tiny movements in the environment; something that has been known since at least the 1940s.

The Schrodinger equation famously provides the means to calculate how particles will behave at quantum level. These calculations are difficult but are made far easier through the use of powerful supercomputers, such as those available through the Irish Centre for High-End Computing (ICHEC).

The Lunghi team at TCD used ICHEC facilities to apply the Schrodinger equation to better understand spin, and to pin down how molecular motion can disrupt particle spin. This breakthrough research was published in Science Advances.

“We want to study spin, to accelerate the development of new materials,” says Lunghi. “There are an infinite number of molecules and compounds that make up materials, which we can produce in the lab, but we want to focus on developing the ones that are most promising, and to do this faster.”

TCD's spin materials lab

The goal of Lunghi and his colleagues is to use artificial intelligence (AI) and machine learning to look at information, accumulated over many decades of particle research and processes it in more clever ways. “That means instead of reading an endless number of scientific papers to try and come up with a ‘recipe’ for new materials, we use computers to do that. We have started to developed algorithms in my laboratory that can do this, and the early results are very encouraging.”

Applications

The study of particle spin is far from being an academic exercise, and it is already being applied in key areas. The exploitation of spin is at the heart of magnetic resonance imaging (MRI) technology that produces detailed anatomical images from inside the body in a safe and non-invasive way.

“We often talk about the possible spinning directions of a particle with one spin type converting into another,” says Lunghi. “With an MRI scan you are measuring the conversion rate of one spin type to another, and this is what provides the contrasts between body tissues during the scanning.”

Spin is also something very important to magnets, which are all around us, from the playful magnets that we put on our fridge to the electric cars we drive, or the hard drives that store images of the pictures we took when on holiday.

Industry is always keen to find new, and better magnets, for new applications. Up to now this has proven extremely difficult, but new insights into spin could change that.

Physicists such as Lunghi are providing greater insight into spin and how it works. That’s crucially important, but the huge challenge for the future is to find ways to control spin and to apply this to develop new quantum sensors.

The fact that spin is so sensitive to tiny changes in the environment means it can applied very effectively into better, more sensitive and effective quantum sensors.

“Spin is a very exciting and fragile property of particles and disturbs very easily,” says Lunghi. “Yet, if we have something that is easily disturbed by the environment then we can use it to sense the environment itself. Atoms are wobbling around, and this constant atomic motion disturbs spin and that is what we are trying to fight against.”

“Our recent paper in Science Advances was about trying to understand that,” he says. “If we can achieve spin stabilisation then it opens the door to a world of new, advanced materials that we can develop in the future.”

Spin control, says Lunghi, can lead to the design of new materials such as quantum sensors, magnets or MRI contrast agents. “In my lab we use machine learning to speed up the design of spin-based materials in a similar way to how other people are doing it to speed up the design of drugs.”

Jonathan Coleman, a professor of chemical physics at TCD, has led research into wearable sensors using graphene and rubber bands

Graphene: manipulating nature down to the level of single atoms

Prof Jonathan Coleman is head of the school of physics at TCD, and principal investigator at the Science Foundation Ireland Centre for Advanced Materials and Bioengineering Research (Amber), where Lungi also works.

Coleman, while not involved in investigating spin, is very much involved in the development of advanced new materials through the manipulation of atoms and molecules — and on developing the new applications that can change the world.

One material he is particularly interested in is graphene, a type of carbon that is made of a two-dimensional, single layer of atoms. Graphite — the stuff in pencils — is made up of layers of graphene, arranged like a deck of cards. Coleman’s group discovered a way to make these sheets.

“In graphite, those building blocks sheets of carbon are just one atom thick,” says Coleman. “We can make this one-atom-thick sheets and use them in new applications. We can manipulate nature, down to the level of the single atom.”

Graphite is not the only layered material around. There are, says Coleman, thousands of layered materials. “That’s important because these materials have different properties to graphene and can be used for different things,” he says.

“It turned out that the real strength and importance of our method for making graphene was that it could be used to make all of these other layered 2D materials. We have used this method for maybe 30 materials up to this point.”

“You might have a 2D material that’s a fantastic battery electrode material,” says Coleman. Or you might have a 2D material that is a fantastic semiconductor for making a transistor. Or you might have a 2D material that’s super strong, to put in a plastic to reinforce the plastic.”

“We can make loads of different 2D materials, depending on what applications study we want to do,” he adds.

HIS MOTHER WAS A WITCH

Why Johannes Kepler is a scientist’s best role model

When people pick the greatest scientist of all-time, Newton and Einstein always come up. Perhaps they should name Johannes Kepler, instead.

Johannes Kepler, whose life spanned from the late 1500s to the early 1600s, was perhaps most remarkable as a scientist for his discovery that planets moved in ellipses around the Sun. Without the ability to throw out his own brilliant idea, he never could've gotten there.
(Credits: August Köhler/public domain (L); Datumizer/Wikimedia Commons (R)

KEY TAKEAWAYS

The annals of history are filled with scientists who had incredible, revolutionary ideas, sought out and found the evidence to support them, and initiated a scientific revolution.

 
But much rarer is someone who has a brilliant idea, discovers that the evidence doesn't quite fit, and instead of doggedly pursuing it, tosses it aside in favor of a newer, better, more successful idea.

 
That's exactly what separates Johannes Kepler from all of the other great scientists throughout history, and why, if we have to choose a scientific role model, we should admire him so thoroughly.

Ethan Siegel

For a great many people in the world, the three hardest words to say are simply, “I was wrong.” Even if the evidence is overwhelmingly decisive that your idea or conception is unsupported, most people will instead find a way to discount or ignore that evidence and stick to their guns. People’s minds are notoriously resistant to change, and the greater their own personal stake in the outcome of the issue under debate, the less open they are to even the possibility that they might be mistaken.

Although it’s often asserted that science is the exception to this general rule, that’s only true of science as a collective enterprise. On an individual basis, scientists are just as susceptible to confirmation bias — overweighting the supporting evidence and discounting the evidence to the contrary — as anyone in any other walk of life. In particular, the greatest difficulties await those who themselves have formulated ideas and invested tremendous efforts, often amounting to years or even decades of time, in hypotheses that simply cannot explain the full suite of data that humanity has amassed. This applies even to the greatest minds in all of history.Albert Einstein could never accept quantum indeterminism as a fundamental property of nature.

Arthur Eddington could never accept quantum degeneracy as a source for holding white dwarfs up against gravitational collapse.

Newton could never accept the experiments that demonstrated the wave nature of light, including interference and diffraction.

And Fred Hoyle could never accept the Big Bang as the correct story of our cosmic origins, even nearly 40 years after the critical evidence, in the form of the Cosmic Microwave Background, was discovered.

But one person stands above the rest as an exemplar for how to behave when the evidence comes in against your brilliant idea: Johannes Kepler, who showed us the way more than 400 years ago. Here’s the story of his scientific evolution, an example we should all strive to emulate.

This chart, from around 1660, shows the signs of the zodiac and a model of the solar system with Earth at the centre. For decades or even centuries after Kepler clearly demonstrated that not only is the heliocentric model valid, but that planets move in ellipses around the Sun, many refused to accept it, instead hearkening back to the ancient idea of Ptolemy and geocentrism.

(Credit: Johannes Van Loon, Andreas Cellarius Harmonia Macrocosmica, 1660/61)

For thousands of years, humans assumed that the Earth was a static, stable, and unchanging point in the Universe, and that all the heavens literally moved around us. Observations seemed to support this: there was no detectable motion occurring on our surface that supported an Earth that either rotated on its axis or revolved around the Sun through space. Instead, there were three key observations that had been made that helped people determine what our best model of the Universe would be.

The entire sky appeared to rotate a full 360 degrees over the course of 24 hours, most evident at night, as the stars rotated about either the northern or southern celestial pole.

The stars themselves appeared to remain fixed in their relative position to one another from night-to-night and even over much longer timescales.

However, there were a few objects that did move relative to one another from night-to-night or day-to-day: the planets, or “wanderers” of the sky.

Additionally, the Sun and Moon shifted in the night as well, as did the entire canopy of stars over longer periods of time. However, it was the first observation that led to the static, stable, unchanging conception of the Universe.

This timelapse view of the night sky from Hyatt Lake shows the sky as it appeared just after the summer solstice on June 21, 2020. The apparent motion of the objects in Earth’s sky could either be explained by the Earth rotating beneath our feet or by the heavens above rotating about a fixed Earth. Simply by watching the skies, we cannot tell these two explanations apart.

(Credit: Bureau of Land Management OR & WA/Kyle Sullivan)

Think about the above observation: that everything in the sky appears to rotate a full 360 degrees over the span of a full day. This could be caused by one of two potential explanations. Either the Earth itself was rotating about some axis, and that our world completed a full rotation once per 24 hours, or the Earth was stationary and everything in the heavens was rotating around it, also once per 24 hours.

How, physically, could we tell these two situations apart? The answers were twofold.

First, it should be possible, if the Earth were rotating, to note a curved trajectory to falling objects. The higher they fell from, the greater the curve would be. Yet no curve was ever observed; in fact this effect wouldn’t be measured until the demonstration of the Foucault pendulum in the 19th century.

Second, a rotating Earth would lead to a difference in the relative positions of the stars from dusk until dawn. The Earth was big, and its diameter had been measured precisely by Eratosthenes in the 3rd century B.C.E., so if any of the stars were closer than most of them, a parallax would appear: similar to holding your thumb out and watching it shift relative to the background as you alternated which eye you used to view it. But no parallax could be seen; in fact this wouldn’t be observed until the 19th century as well! 

The stars that are closest to Earth will appear to shift periodically with respect to the more distant stars as the Earth moves through space in orbit around the Sun. Before the heliocentric model was established, we weren’t looking for “shifts” with a ~300,000,000 kilometer baseline over the span of ~6 months, but rather a ~12,000 kilometer baseline over the span of one night: Earth’s diameter as it rotated on its axis.(Credit: ESA/ATG medialab)

It’s easy to see, based on what we knew and could observe at the time, how we’d conclude that the Earth was static and fixed, while the heavenly bodies all moved around us.

Then, there were those additional observations that required an explanation: why did the stars remain fixed relative to one another while the planets appeared to “wander” through the sky?

It was quickly modeled that the planets, as well as the Sun and the Moon, must be closer to Earth than the stars were, and that these bodies must be in motion relative to one another.

With a fixed, static Earth, that meant that it must be the planets themselves that were in motion. The motion must have been incredibly complex, however. While the planets overwhelmingly appeared to move in one direction relative to the backdrop of stars on a night-to-night basis, every once in a while, the planets would:slow down in their usual motion,
come to a complete stop,
reverse their motion to move opposite their original direction (a phenomenon known as retrograde motion),
would then slow and stop again,
and finally would continue on in their normal (prograde) direction of motion.

This phenomenon was the most challenging aspect of planetary motion to model and understand.

Mars, like most planets, normally migrates very slowly across the sky in one predominant direction. However, a little less than once a year, Mars will appear to slow down in its migration across the sky, stop, reverse directions, speed up and slow down, and then stop again, resuming its original motion. This retrograde (west-to-east) period stands in contrast to Mars’s normal prograde (east-to-west) motion.(Credit: E. Siegel/Stellarium)

The prevailing assumption, since the Earth had already been deemed to be static, was that the planets themselves each typically moved in circular paths around the Earth, but atop those circles were smaller circles known as “epicycles” that they moved about as well. When the motion through the smaller circle proceeded in the opposite direction from the main motion through the larger circle, the planet would appear to reverse course for a brief while: a period of retrograde motion. Once the two motions lined up in the same direction again, prograde motion would resume.

Although epicycles did not start with Ptolemy — with whose name they are now synonymous — Ptolemy did make the best, most successful model of the Solar System that incorporated epicycles. In his model, the following occurred.Each planet’s orbit was dominated by a “great circle” that it moved along, moving around the Earth.
Atop each great circle, a smaller circle (an epicycle) existed, with the planet moving along the outskirts of that small circle, with the center of the small circle always moving along the larger one.
And the Earth, rather than being at the center of the great circle, was offset from that center by a particular amount, with the specific amount differing for each planet.

That was the Ptolemaic theory of epicyclic motion, leading to a geocentric model of the Solar System.

One of the great puzzles of the 1500s was how planets moved in an apparently retrograde fashion. This could either be explained through Ptolemy’s geocentric model (L), or Copernicus’ heliocentric one (R). However, getting the details right to arbitrary precision was something that would require theoretical advances in our understanding of the rules underlying the observed phenomena, which led to Kepler’s laws and eventually Newton’s theory of universal gravitation.(Credit: E. Siegel/Beyond the Galaxy)

Going all the way back to ancient times, there was some evidence — from Archimedes and Aristarchus, among others — that a Sun-centered model for planetary motion was considered. But once again, the lack of any detectable motion for the Earth or of any detectable parallax for the stars failed to provide the corroborating evidence. The idea languished in obscurity for centuries, but was finally revived in the 16th century by Nicolaus Copernicus.

The great idea of Copernicus was that if the planets moved in circles around the Sun, then during most times, the inner planets would orbit more quickly than the outer ones. From the perspective of any one planet, the others would appear to migrate relative to the fixed stars. But whenever an inner planet passed by and overtook an outer planet, then retrograde motion would occur, as the normal apparent direction-of-motion would appear to reverse.

Copernicus realized this and put forth his theory of a Sun-centered Solar System, or a heliocentric (rather than geocentric) one, offering it up as an exciting and possibly superior alternative to Ptolemy’s older Earth-centered model

.
This simulation of the Solar System over the duration of one Earth-year shows the innermost planet, Mercury, “overtaking” the Earth from an interior orbit three independent times during the year. With Mercury’s orbital period of just 88 days, three or four retrograde periods exist every year for Mercury: the only planet annually with more than one. The outer planets, by contrast, experience retrograde only when Earth overtakes them: roughly once per year for all planets except Mars, which experiences them less frequently.(Credit: dynamicdiagrams.com, 2011, now defunct)

But in science, we always have to follow the evidence, even if we loathe the path it leads us down. It’s not aesthetics, elegance, naturalness, or personal preference that decides the issue, but rather the success of the model in predicting what can be observed. Leveraging circular orbits for both the Ptolemaic and the Copernican models, Copernicus was frustrated to discover that his model gave less successful predictions when compared against Ptolemy’s. The only way Copernicus could devise to equal Ptolemy’s successes, in fact, relied on employing the same ad hoc fix: by adding epicycles, or small circles, atop his planetary orbits!

In the decades following Copernicus, others took interest in the Solar System. Tycho Brahe, for example, constructed the best naked eye astronomy setup in history, measuring the planets as precisely as human vision allows: to within one arc-minute (1/60th of a degree) during every night that planets were visible towards the end of the 1500s. His assistant, Johannes Kepler, attempted to make a glorious, beautiful model that fit the data precisely.

Given that there were six known planets (if you included the Earth as one of them), and exactly five (and only five) perfect polyhedral solids — the tetrahedron, cube, octahedron, icosahedron, and dodecahedron — Kepler constructed a system of nested spheres called the Mysterium Cosmographicum

.
Kepler’s original model of the Solar System, the Mysterium Cosmographicum, consisted of the 5 Platonic solids defining the relative radii of 6 spheres, with the planets orbiting around the circumferences of those spheres. As beautiful as this is, it couldn’t describe the Solar System as well as ellipses could, or even as well as Ptolemy’s model could.(Credit: Johannes Kepler, 1597)

In this model, each planet orbited along a circle defined by the circumference of one of the spheres. Outside of it, one of the five Platonic solids was circumscribed, with the sphere touching each of the faces in one spot. Outside of that solid, another sphere was circumscribed, with the sphere touching each of the solid’s vertices, with the circumference of that sphere defining the orbit of the next planet out. With six spheres, six planets, and five solids, Kepler made this model where “invisible spheres” held up the Solar System, accounting for the orbits of each of Mercury, Venus, Earth, Mars, Jupiter, and Saturn.

Kepler formulated this model in the 1590s, and Brahe boasted that only his observations could put such a model to the test. But no matter how Kepler did his calculations, not only did disagreements with observation remain, but Ptolemy’s geocentric model still made superior predictions.

In the face of this, what do you think Kepler did?Did he tweak his model, attempting to save it?
Did he distrust the critical observations, demanding new, superior ones?
Did he make additional postulates that could explain what was truly occurring, even if it was unseen, in the context of his model?

No. Kepler did none of these. Instead, he did something revolutionary: he put his own ideas and his own favored model aside, and looked at the data to see if there was a better explanation that could be derived from demanding that any model needed to agree with the full suite of observational data.
Kepler’s second law states that planets sweep out equal areas, using the Sun as one focus, in equal times, regardless of other parameters. The same (blue) area is swept out in a fixed time period. The green arrow is velocity. The purple arrow directed towards the Sun is the acceleration. Planets move in ellipses around the Sun (Kepler’s first law), sweep out equal areas in equal times (his second law), and have periods proportional to their semimajor axis raised to the 3/2 power (his 3rd law).

(Credit: Gonfer/Wikimedia Commons, using Mathematica)

If only we could all be so brave, so brilliant, and at the same time, so humble before the Universe itself! Kepler calculated that ellipses, not circles, would better fit the data that Brahe had so painstakingly acquired. Although it defied his intuition, his common sense, and even his personal preferences for how he felt the Universe ought to have behaved — indeed, he thought that the Mysterium Cosmographicum was a divine epiphany that had revealed God’s geometrical plan for the Universe to him — Kepler was successfully able to abandon his notion of “circles and spheres” and instead used what seemed to him to be an imperfect solution: ellipses.

It cannot be emphasized enough what an achievement this is for science. Yes, there are many reasons to be critical of Kepler. He continued to promote his Mysterium Cosmographicum even though it was clear ellipses fit the data better. He continued to mix astronomy with astrology, becoming the most famous astrologer of his time. And he continued the long tradition of apologetics: claiming that ancient texts meant the opposite of what they said in order to reconcile the acceptability of the new knowledge that had emerged.

But it was through this revolutionary action, of abandoning his model for a new one that he himself devised to explain the observations more successfully than ever before, that Kepler’s laws of motion became elevated to scientific canon.

Tycho Brahe conducted some of the best observations of Mars prior to the invention of the telescope, and Kepler’s work largely leveraged that data. Here, Brahe’s observations of Mars’s orbit, particularly during retrograde episodes, provided an exquisite confirmation of Kepler’s elliptical orbit theory.(Credit: Wayne Pafko)

Even today, more than four full centuries after Kepler, we all learn his three laws of planetary motion in schools.Planets move in ellipses around the Sun, with the Sun at one of the ellipse’s two focal points.
Planets sweep out equal areas, with the Sun at once focus, in equal amounts of time.
And planets orbit in time periods proportional to their semimajor axes (half of the longest-axis of the ellipse) to the 3/2 power.

These were the first calculations that advanced the science of astronomy beyond the stagnated realm of Ptolemy, and they paved the way for Newton’s theory of universal gravitation, which transformed these laws from simple descriptions of how motion occurred to one that was physically motivated. By the end of the 17th century, all of Kepler’s laws could be derived simply from the laws of Newtonian gravity.

But the greatest achievement of all was the day Kepler put his own idea of a Mysterium Cosmographicum — an idea that he was arguably more emotionally attached to than any other — in order to follow the data, wherever it led him. That brought him to elliptical orbits for the planets, which kicked off the revolution in our understanding the physical universe around us, i.e., the modern sciences of physics and astronomy, that continues to the present day. Like all scientific heroes, Kepler certainly had his faults, but the ability to admit when you’re wrong, to reject your insufficient ideas, and to follow the data wherever it leads are traits we should all aspire to. Not only in science, of course, but in all aspects of our lives.

XAOS AND ALL THAT


Jasmin Merdan//Getty Images

BY SARAH WELLS

POP MECH

PUBLISHED: SEP 22, 2022

A branch of math called chaos theory looks at how small changes to a system can result in unpredictable behavior.

Chaos theory explains how complex systems work in multiple fields, including astrophysics, climate change, and neuroscience.

Chaos doesn’t always mean systems are totally unpredictable. Researchers have identified patterns that help them predict overall movements.

“Does the flap of a butterfly’s wings in Brazil set off a tornado in Texas?” Might sound like the type of question posed by science fiction explorers to reveal the precarity of time travel, but in reality it’s the title of an MIT professor’s 1972 paper presented in a Sheraton conference room to members of the American Association for the Advancement of Science.

Meteorologist Edward Lorenz wrote the paper, and while the concept seems far-fetched, the analogy actually highlights an idea underlying everything from planetary motion to climate change: chaos.

More precisely, this example works to explain a kind of math called chaos theory, which looks at how small changes made to a system’s initial conditions—like the extra gust of wind from a butterfly’s wings—can result in seemingly unpredictable behavior. (For example, a tornado in Texas.)

While mathematicians wouldn’t necessarily call themselves chaos theorists today, the theory does play a role in the study of dynamical systems, which Kevin Lin, associate professor of math at the University of Arizona, says helps us study everything from climate change to neuroscience.

“Chaos is a fact of life … and a part of dynamical systems theory,” Lin explains to Popular Mechanics in an email. “Some systems are inherently chaotic, while others are not. Many [mathematicians] are also very interested in how certain systems can exhibit both types of behavior, and transition between these different regimes under different conditions.”

The Origins of Chaos Theory

While Lorenz might be known for coining the “Butterfly Effect” in relation to chaos theory, Lin says that the discovery of chaos theory actually dates back to the 1890s and a mathematician and physicist named Henri Poincaré. In his relatively short life, Poincaré made an impact on a wide range of topics, from gravitational waves to quantum mechanics.

These efforts also included explaining why the famed three-body problem—which tries to explain the motion of three planetary bodies orbiting each other—could not be solved. Chief among those reasons was that the system was sensitive to small, unpredictable perturbations ... AKA, chaos.

photovideostock//Getty Images

“Prior to Poincaré, mathematicians studying dynamics, i.e., the behavior of systems governed by differential equations … focused on one solution at a time,” Lin says. “Poincaré introduced concepts and tools for thinking about dynamics ‘globally,’ that is, how whole sets of solutions evolve in time.”

Despite not being first to the idea, it was Lorenz’s discovery of chaos that “broke into popular culture,” Mark Levi, professor and head of the math department at Penn State, tells Popular Mechanics in an email.

Butterfly analogy aside, Lorenz’s discovery was actually made when using an early computer to study weather models. When re-running a weather simulation from partway through its calculation, Lorenz was surprised to see that the same data and conditions had somehow made drastically different predictions. As it turns out, the difference came down to the significant digits used by the machine for calculation, demonstrating that systems like weather patterns can be very sensitive to their initial conditions.

Is Chaos Always Unpredictable?

While many natural systems have chaotic behavior, this doesn’t necessarily mean that they’re all unpredictable, or non-deterministic. When studying how these systems behave in phase space—a kind of multidimensional map of the system’s states through time—researchers have identified patterns that help them predict the overall movement of a system.

Artwork of a Lorenz Attractor, named after Edward Lorenz, who developed a system of ordinary differential equations. The Lorenz attractor is a set of chaotic solutions of the Lorenz system which, when plotted, resemble a butterfly or figure eight. For the system’s sensitivity to initial conditions, Lorenz coined the term butterfly effect. This effect is the underlying mechanism of deterministic chaos.

PASIEKA//Getty Images

Like gravity attracts planetary bodies or an ocean current directs sea creatures, researchers found that there are invisible “attractors” that chaotic systems are drawn to. These attractors look different for different systems, but often take the form of recursive, fractal shapes.

Sadly, finding an attractor for every type of chaotic system is a bit of pipe dream, says Levi.

“Even ridiculously simple systems, such as a pendulum with an oscillating pivot, are chaotic and too complex for complete understanding—never mind the motion of the atmosphere or the oceans,” he says.
How Chaos Helps Us Today

Chaos theory may be fairly theoretical at this point, but the study of dynamical systems is much more tangible, Lin says. As part of his research, Lin uses dynamics to study how seemingly random firings of neurons in our brains transform into complex information systems.

“The brain is an example of a system that is highly unpredictable when you look at it closely,” he says. “Nevertheless, it functions very reliably. Therein lies a conundrum: how can something seemingly random reliably encode and process information?”

Scientists and mathematicians don’t have a clear answer to this question yet, but Lin says he’s enjoying the ride through chaos. “At least for me,” Lin says,“it’s fun!”

SARAH WELLS is a science and technology journalist based in Boston interested in how innovation and research intersect with our daily lives. She has written for a number of national publications and covers innovation news at Inverse.

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How global warming affects astronomical observations

by University of Bern

The VLT's Laser Guide Star: A laser beam launched from VLT´s 8.2-meter Yepun telescope

 crosses the majestic southern sky and creates an artificial star at 90 km altitude in the 

high Earth´s mesosphere. The Laser Guide Star (LGS) is part of the VLT´s Adaptive 

Optics system and it is used as reference to correct images from the blurring effect of the 

atmosphere. Credit: ESO / G. Hüdepohl (atacamaphoto.com)

The quality of ground-based astronomical observations delicately depends on the clarity of the atmosphere above the location from which they are made. Sites for telescopes are therefore very carefully selected. They are often high above sea level, so that less atmosphere stands between them and their targets. Many telescopes are also built in deserts, as clouds and even water vapor hinder a clear view of the night sky.

A team of researchers led by the University of Bern and the National Centre of Competence in Research (NCCR) PlanetS shows in a study, published in the journal Astronomy & Astrophysics and presented at the Europlanet Science Congress 2022 in Granada, how one of the major challenges of our time—anthropogenic climate change—now even affects our view of the cosmos.

A blind spot in the selection process

"Even though telescopes usually have a lifetime of several decades, site selection processes only consider the atmospheric conditions over a short timeframe. Usually over the past five years—too short to capture long-term trends, let alone future changes caused by global warming," Caroline Haslebacher, lead author of the study and researcher at the NCCR PlanetS at the University of Bern, points out.

The team of researchers from the University of Bern and the NCCR PlanetS, ETH Zurich, the European Southern Observatory (ESO) as well as the University of Reading in the UK therefore took it upon themselves to show the long-term perspective.

Worsening conditions around the globe

Their analysis of future climate trends, based on high resolution global climate models, shows that major astronomical observatories from Hawaii to the Canary Islands, Chile, Mexico, South Africa and Australia will likely experience an increase in temperature and atmospheric water content by 2050. This, in turn, could mean a loss in observing time as well as a loss of quality in the observations.

"Nowadays, astronomical observatories are designed to work under the current site conditions and only have a few possibilities for adaptation. Potential consequences of the climatic conditions for telescopes therefore include a higher risk of condensation due to an increased dew point or malfunctioning cooling systems, which can lead to more air turbulence in the telescope dome," Haslebacher says.

The fact that the effects of climate change on observatories had not been taken into account before was not an oversight, as study co-author Marie-Estelle Demory says, but more due to modeling limitations. "This is the first time that such a study has been possible. Thanks to the higher resolution of the global climate models developed through the Horizon 2020 PRIMAVERA project, we were able to examine the conditions at various locations of the globe with great fidelity—something that we were unable to do with conventional models. These models are valuable tools for the work we do at the Wyss Academy," says the senior scientist at the University of Bern and member of the Wyss Academy for Nature.

"This now allows us to say with certainty that anthropogenic climate change must be taken into account in the site selection for next-generation telescopes, and in the construction and maintenance of astronomical facilities," says Haslebacher.Long-term liquid water also on non-Earth-like planets?

More information: C. Haslebacher et al, Impact of climate change on site characteristics of eight major astronomical observatories using high-resolution global climate projections until 2050. Projected increase in temperature and humidity leads to poorer astronomical observing conditions, Astronomy & Astrophysics (2022). DOI: 10.1051/0004-6361/202142493

Journal information: Astronomy & Astrophysics 

Provided by University of Bern 

Astronomers unveil new—and puzzling—features of mysterious fast radio bursts

by University of Nevada, Las Vegas

Artist's conception of Five-hundred-meter Aperture Spherical radio Telescope (FAST) in 

China. Credit: Jingchuan Yu

Fast radio bursts (FRBs) are millisecond-long cosmic explosions that each produce the energy equivalent to the sun's annual output. More than 15 years after the deep-space pulses of electromagnetic radio waves were first discovered, their perplexing nature continues to surprise scientists—and newly published research only deepens the mystery surrounding them.

In the Sept. 21 issue of the journal Nature, unexpected new observations from a series of cosmic fast radio bursts by an international team of scientists—including UNLV astrophysicist Bing Zhang—challenge the prevailing understanding of the physical nature and central engine of FRBs.

The cosmic FRB observations were made in late spring 2021 using the massive Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China. The team, led by Heng Xu, Kejia Lee, Subo Dong from Peking University, and Weiwei Zhu from the National Astronomical Observatories of China, along with Zhang, detected 1,863 bursts in 82 hours over 54 days from an active fast radio burst source called FRB 20201124A.

"This is the largest sample of FRB data with polarization information from one single source", said Lee.

Recent observations of a fast radio burst from our Milky Way galaxy suggest that it originated from a magnetar, which is a dense, city-sized neutron star with an incredibly powerful magnetic field. The origin of very distant cosmological fast radio bursts, on the other hand, remains unknown. And the latest observations leave scientists questioning what they thought they knew about them.

"These observations brought us back to the drawing board," said Zhang, who also serves as founding director of UNLV's Nevada Center for Astrophysics. "It is clear that FRBs are more mysterious than what we have imagined. More multi-wavelength observational campaigns are needed to further unveil the nature of these objects."

What makes the latest observations surprising to scientists is the irregular, short-time variations of the so-called "Faraday rotation measure", which is the strength of the magnetic field and density of particles in the vicinity of the FRB source. The variations went up and down during the first 36 days of observation and suddenly stopped during the last 18 days before the source quenched.

"I equate it to filming a movie of the surroundings of an FRB source, and our film revealed a complex, dynamically evolving, magnetized environment that was never imagined before," said Zhang. "Such an environment is not straightforwardly expected for an isolated magnetar. Something else might be in the vicinity of the FRB engine, possibly a binary companion," added Zhang.

To observe the host galaxy of the FRB, the team also made use of the 10-m Keck telescopes located at Mauna Kea in Hawaii. Zhang says that young magnetars are believed to reside in active star-forming regions of a star-forming galaxy, but the optical image of the host galaxy shows that—unexpectedly—the host galaxy is a metal-rich barred spiral galaxy like our Milky Way. The FRB location is in a region where there is no significant star-forming activity.

"This location is inconsistent with a young magnetar central engine formed during an extreme explosion such as a long gamma-ray burst or a superluminous supernova, widely speculated progenitors of active FRB engines," said Dong.

The study, "A fast radio burst source at a complex magnetized site in a barred galaxy", appeared September 21 in the journal Nature and includes 74 co-authors from 30 institutions. In addition to UNLV, Peking University, and the National Astronomical Observatories of China, collaborating institutions also include Purple Mountain Observatory, Yunnan University, UC Berkeley, Caltech, Princeton University, University of Hawaii, and other institutions from China, the U.S., Australia, Germany, and Israel.Astronomers discover clues that unveil the mystery of fast radio bursts

More information: H. Xu et al, A fast radio burst source at a complex magnetized site in a barred galaxy, Nature (2022). DOI: 10.1038/s41586-022-05071-8

Journal information: Nature 

Provided by University of Nevada, Las Vegas 

A 4-BILLION-YEAR JOURNEY —

Asteroid Ryugu was once part of a much larger parent body, new results find

Hayabusa2 returned to Earth with soil samples from the asteroid in December 2020

JENNIFER OUELLETTE

- 9/26/2022, 

Enlarge / First spotted by astronomers in May 1999, 

Ryugu is essentially a large collection of loose rubble.

The Japanese spacecraft Hayabusa2 returned to Earth in December 2020 bearing soil samples collected from a nearby asteroid, 162173 Ryugu. Those samples were divided between six scientific teams around the world for cutting-edge analysis to determine their composition in hopes of learning more about how such bodies form. The results of the first year of analysis of those samples appeared in a new paper published in the journal Science and included the detection of a precious drop of water embedded in a crystal.

These findings suggest that Ryugu was once part of a much larger asteroid that formed out of various materials some two million years after our Solar System (some 4.5 billion years ago). Over the next 3 million years, the parent body's carbon dioxide ice melted, resulting in a water-rich interior and a drier surface. When another space rock hit the parent body about a billion years ago, it broke apart, and some of the resulting debris formed Ryugu. An accompanying computer simulation supports this formation history, backed by the results of the sample analyses.

First spotted by astronomers in May 1999, Ryugu is essentially a large collection of loose rubble. As much as 50 percent of its volume could be empty space. Like the asteroid Bennu, Ryugu is shaped a bit like a spinning top: a round shape with a sharp equatorial ridge. Its name derives from a Japanese folktale in which a fisherman travels to an underwater palace called Ryūgū-jō ("dragon palace") on the back of a turtle.

Scientists recovered a capsule containing samples

 from Ryugu after it landed in Australia.
JAXA

Hayabusa2 has been in space since 2014, and it slowly made its way to an orbit 20 km above the surface of the asteroid Ryugu. In late 2018, the spacecraft made a close approach to the asteroid and released two small, solar-powered robots that hopped around on the surface. One of those was called MASCOT, the Mobile Asteroid Surface Scout. Despite landing upside-down, the robot eventually jumped into the right orientation. MASCOT's camera, a magnetometer, a radiometer, and an infrared spectrometer also sent back images to give scientists some sense of the materials around it and associate their properties with specific rocks. As Ars Science Editor John Timmer reported in 2019:

The first was darker and rough, with a surface appearance the researchers describe as "cauliflower-like." The second was brighter and had smoother surfaces and more angular shapes.... The Hyabusa2 team suspects that the features of the two different materials are the product of the heating/cooling cycles that take place as the rocks are exposed first to sunlight and then to the darkness of space. In some cases, this leads to the shattering of the rock, producing the smoother surfaces seen among some of the materials. In others, the rock slowly disintegrates, losing its internal structure and producing the other rocks observed by MASCOT.

The weird thing about that, however, is that crumbling and shattering rocks typically produce dust and sand-like materials. Yet there were no signs of any of this... They assume the smaller grains are either lost to space or end up working their way into the interior of the rubble. But the rocks that could be seen by MASCOT were all tens of centimeters across or larger (some were tens of meters).

Hayabusa2 collected surface samples by snuggling up to the asteroid and shooting it. The probe had a sample-gathering "horn," which was placed against the asteroid's surface. Then Hayabusa2 fired a bullet into the asteroid's surface, blasting material loose that was gathered by the horn and stored for return to Earth. Hayabusa2 also carried a heavier bullet intended to blast off the surface material to expose material that has remained protected for billions of years. A capsule containing the capsules landed in Australia in December 2020.

Last month, one team of researchers published the results of their analysis of dust samples from Ryugu in The Astrophysical Journal Letters, concluding that some of those grains of dust are older than our Solar System. The age of the grains in their dust can be identified and dated by their isotopic signatures, and the team compared the Ryugu dust samples to grains found in carbonaceous chondrite meteorites that have been found on Earth. The Ryugu dust sample held grains identical to others that have been seen in some of those meteorites that predate our Solar System.


Enlarge / UChicago and Argonne beamline scientist Barbara Lavina observes one of the tiny asteroid fragments through a microscope, with the magnified image on the screen beside her.
Jason Creps/Argonne National Laboratory

This latest paper adds to those results to reveal even more of Ryugu's secrets. For instance, co-author scientists at Argonne National Laboratory used the ultra-bright X-ray beams of the Advanced Photon Source to determine the chemical and structural makeup of Ryugu samples at the atomic scale. (The samples are tiny, between 400 microns to 1 millimeter in diameter, but the beamline can be focused to 15 microns.)

That analysis showed a porous, fine-grained structure shared by all the samples and a chemical makeup similar to rare Cl chondrite meteorites that have hit the Earth. That porosity indicates the asteroid once held water and ice, while the grains that make up Ryugu are much finer than one would expect if it had formed at higher temperatures—in keeping with the prevailing hypothesis that the asteroid formed in the outer reaches of the Solar System. There was also a large amount of an iron sulfide called pyrrhotite, which was not found in the meteorite samples used for comparison.

“Our results and those from other teams show that these asteroid samples are different from meteorites, particularly because meteorites have been through fiery atmosphere entry, weatherization, and in particular oxidation on Earth,” said co-author Michael Hu, a physicist at Argonne. ​“This is exciting because it’s a completely different kind of sample, from way out in the Solar System.”

Meanwhile, co-authors from Goethe University Frankfurt used synchrotron radiation-induced X-ray fluorescence computer tomography (SR-XRF-CT) on 16 sample particles from Ryugu. The presence of a fine vein of the iron oxide magnetite and a phosphate mineral called hydroxyapatite is in keeping with the asteroid forming at a surprisingly low temperature of less than 40° Celsius. The German team also picked up traces of rare earth metals at significantly higher concentrations than elsewhere in the solar system. The fact that those metal concentrations are equally distributed indicates that Ryugu "is a very pristine asteroid that represents the beginnings of our solar system," according to co-author Frank Brenker.

Perhaps the most intriguing finding: a drop of carbonated water (trapped in a crystal) containing salt and organic matter in samples from Ryugu. That's consistent with a hypothesis that asteroids like Ryugu may have brought water to Earth and helped seed the origin of life. Additional analytical results from the samples will be published in later papers and will eventually be compiled into a summary of the collective key findings.

DOI: Science, 2022. 10.1126/science.abn8671 (About DOIs).

Asteroid Ryugu is made of rubble from the outer solar system

Particles plucked from Ryugu and returned to Earth reveal the near-Earth asteroid originated beyond Jupiter, helping shed light on the evolution of the asteroid belt.

By Theo Nicitopoulos  |  Published: Monday, September 26, 2022

The Japanese spacecraft Hayabusa2 is hard at work dislodging and then collecting samples from asteroid Ryugu in this artist's concept.

JAXA

Early in the morning on Dec. 6, 2020, JAXA’s Hayabusa2’s sample-return capsule streaked through the sky over Woomera, Australia. The heat-shielded capsule, packed with material blasted from the surface of asteroid Ryugu in 2018, descended toward the desert sand. After tracking the precious cargo to its landing site, scientists successfully recovered the most pristine samples ever obtained of a carbon-rich asteroid.

Scientists have begun analyzing the samples. In one recent study published Aug. 15 in Nature Astronomy, researchers discovered the first evidence that Ryugu formed from material that originated in the outer solar system. The results also support the idea that the asteroid belt (located between Mars and Jupiter) may have been populated by planetesimals from two distinct sources when the solar system was still in its infancy.

“When I obtained the initial results from my instruments, I could not believe it,” Motoo Ito, a cosmochemist at the Japan Agency for Marine-Earth Science and Technology and lead author of the latter study, tells Astronomy.

Diving deep into asteroid dust

When Ito and his colleagues cracked open and analyzed the Ryugu particle samples, they found higher abundances of heavier hydrogen and nitrogen isotopes than what is typically seen on Earth and in meteorites. Ito analyzed the sample several times using different approaches to confirm the results.

Japan’s Hayabusa2 spacecraft casts its shadow on asteroid Ryugu after shooting it with a projectile to dislodge and collect surface samples.

JAXA

Ito’s team found that Ryugu has a composition similar to that of carbonaceous chondrite (CC) meteorites. Such objects have not experienced extensive heating, and hence are believed to have formed farther out in the solar system, beyond the orbit of Jupiter.

Carbonaceous chondrites are relatively rich in carbon and organic materials, and they contain minerals with chemically bound water, which indicates they originally contained water-ice. Non-CCs, on the other hand, are thought to have originated closer to the Sun, where temperatures would have vaporized any volatiles like water, leaving behind primarily silicate materials.

“The evidence from this study is the strongest we have so far that asteroids came from two different reservoirs,” says planetary scientist Bojan Novakovic of the University of Belgrade in Serbia, who was not involved in the study.

Some previously analyzed meteorites and interplanetary dust particles also show evidence of being from the outer solar system, but the Ryugu sample is the most pristine example recovered to date. That’s because the extraterrestrial material didn’t have to tear through our atmosphere to get to Earth — at least not unprotected.

“Exposure to the terrestrial environment is a problem,” says Ito. “The atmosphere is full of water and oxygen, and we are surrounded by organic material, so we have no idea which material is extraterrestrial.”

A cosmic trip

As for how far-flung carbonaceous chondrites ultimately ended up in the main asteroid belt, the most likely answer is that they were scattered inwards by the gas giants. Today’s solar system is well behaved, but early on, the orbits of the planets were likely migrating. The resulting gravitational interactions would have wreaked havoc on smaller bodies such as asteroids.

“Asteroids get a ‘kick’ if they have a close encounter with a planet,” says Novakovic.

Once in the main belt, the rubble from numerous past asteroid collisions would have accreted to form new amalgamated asteroids like Ryugu. Then, over time, weak but persistent thermal radiation forces, along with perturbations from Saturn’s gravity, would have nudged Ryugu even further inward, says Novakovic.

“Close encounters with Mars may have induced the final kick into near-Earth space,” he adds.

Ryugu’s journey may have happened relatively quickly in astronomical terms, perhaps tens of millions of years. Meanwhile, Hayabusa2’s round-trip journey took only seven years. That may have seemed long to researchers, but it’s a blink of the eye in cosmic terms.

“The first time I saw the sample in the chamber was surreal,” says Ito. “I had imagined for many years that these precious samples would arrive to conduct studies.”

Einstein’s theory of general relativity passes another test, with implications for dark matter and dark energy

The theory is accurate within at least one part in a quadrillion.

Credit: canbedone / Adobe Stock

Don Lincoln
 SEPTEMBER 23, 2022

KEY TAKEAWAYS

Scientists carried out an ultra-precise test of a core premise of Einstein’s modern theory of gravity. The theory stood up with an accuracy of one part in a quadrillion.

 
The assertion that inertial and gravitational mass are the same is known as the equivalence principle, and Einstein hard-wired equivalence into his theory of gravity.

 
The latest test rules out some alternative theories of gravity, but not all of them. The research has significant consequences for conjectural ideas such as dark energy and dark matter.

Researchers used a satellite orbiting the Earth to carry out an ultra-precise test of a core premise of Einstein’s theory of general relativity, which is the modern theory of gravity. The question is whether two different kinds of mass — gravitational and inertial — are identical. The scientists found that two objects aboard the satellite fell toward Earth at the same rate, with an accuracy of one part in a quadrillion. This successful test of Einstein’s theory has substantial implications for current cosmic mysteries — for example, the question of whether dark matter and dark energy exist.
Fooling the ancients

Gravity is the force that holds the Universe together, tugging at distant galaxies and guiding them in an eternal cosmic dance. The strength of gravity is governed partly by the distance between two objects, but also by the masses of objects. An object with more mass experiences more gravity. The technical name for this type of mass is “gravitational mass.”

Mass has another property, which one might call inertia. This is an object’s tendency to resist changes in motion. In other words, more massive things are harder to move: It’s easier to push a bicycle than a car. The technical name for this type of mass is “inertial mass.”

There is no reason a priori to assume that gravitational mass and inertial mass are the same. One governs the force of gravity, while the other governs motion. If they were different, heavy and light objects would fall at different rates, and indeed philosophers in ancient Greece observed that a hammer and a feather fall differently. Heavy objects certainly do seem to fall faster than light ones. We now know that air resistance is the culprit, but that was hardly obvious in the past.

The situation was clarified in the 17th century, when Galileo performed a series of experiments using ramps and spheres of different masses to show that objects of different masses fall at the same rate. (His oft-cited experiment of dropping balls from the Tower of Pisa is probably apocryphal.) And in 1971, astronaut David Scott convincingly repeated Galileo’s experiment on the airless Moon, when he dropped a hammer and a feather, and they fell identically. The ancient Greeks had been fooled.
Dark conjecture

The assertion that inertial and gravitational mass are the same is known as the equivalence principle, and Einstein hard-wired equivalence into his theory of gravity. General relativity successfully predicts how objects fall in most circumstances, and the scientific community accepts it as the best theory of gravity.

However, “most” circumstances does not mean “all,” and astronomical observations have revealed some perplexing mysteries. For one, galaxies rotate faster than their stars and the gases within them can account for or than Einstein’s theory of gravity can explain. The most accepted explanation for this discrepancy is the existence of a substance called dark matter — matter that does not emit light. Another cosmic conundrum is the observation that the expansion of the Universe is accelerating. To explain this oddity, scientists have postulated that the Universe is full of a repulsive form of gravity called dark energy.

However, these are matters of informed conjecture. It could be that we do not fully understand gravity or the laws of motion. Before we can have any confidence that dark matter and dark energy are real, we need to validate Einstein’s theory of general relativity with very high precision. To do that, we need to show that the equivalence principle is true.

While Isaac Newton tested the equivalence principle back in the 1600s, modern efforts are much more accurate. In the 20th century, astronomers bounced lasers off mirrors left on the moon by Apollo astronauts to show that inertial and gravitational mass are the same to an accuracy of one part in 10 trillion. That achievement was impressive. But the most recent experiment went further still.
General relativity passes another test

A group of researchers called the MicroSCOPE collaboration launched a satellite into space in 2016. Cylinders of titanium and platinum were on board, and the scientists’ intent was to test the equivalence principle. By putting their apparatus in space, they isolated the equipment from vibrations and small gravitational differences created by nearby mountains, underground oil and mineral deposits, and the like. The scientists monitored the location of the cylinders using electric fields. The idea is that if the two objects orbited differently, they would need to use two different electric fields to keep them in place.

What they found was that the required electric fields were the same, allowing them to determine that any differences in inertial and gravitational mass came out to less than one part in a quadrillion. Essentially, they made a precise validation of the equivalence principle.

While this is an expected outcome from the point of view of general relativity, it has very substantial consequences for the study of dark matter and dark energy. While those ideas are popular, some scientists believe that the rotational properties of galaxies can be better explained by new theories of gravity. Many of these alternative theories imply that the equivalence principle is not quite perfect.

The MicroSCOPE measurement saw no violation of the equivalence principle. Its results rule out some alternative theories of gravity, but not all of them. Researchers are preparing a second experiment, called MicroSCOPE2, that should be about 100 times more precise than its predecessor. If it sees deviations of the principle of equivalence, it will give scientists crucial guidance toward developing new and improved theories of gravity.

LA REVUE GAUCHE - Left Comment: Search results for DARK MATTER 

LA REVUE GAUCHE - Left Comment: Search results for DARK ENERGY 

LA REVUE GAUCHE - Left Comment: Search results for ETHER 

Cyclones circling Jupiter's poles still baffling space scientists

Infrared image of the northern hemisphere of Jupiter as seen by JIRAM. 

Credit: Nature Astronomy (2022). DOI: 10.1038/s41550-022-01774-0

A team of space scientists affiliated with multiple institutions in the U.S., working with a colleague from Italy and another from France has used modeling to partially explain the resilience of cyclones circling Jupiter's poles. In their paper published in the journal Nature Astronomy, the group describes how they analyzed images captured by the Juno space probe and used what they learned to create shallow water models that might at least partly explain how the cyclones last so long.

In 2016, NASA's Juno space probe entered an orbit around Jupiter. Unlike other such probes it has been circling the planet from pole to pole, rather than around its equator. As the probe began sending back pictures of the planet from this new perspective, researchers looking at them found a surprise. Not only was there a single cyclone sitting atop each of the poles, but both were surrounded by more cyclones. As time has passed, more pictures of the poles have arrived and the researchers studying them continue to be surprised by the stability of the cyclones—the original ones are still there today and have not even changed shape. Such behavior is of course unheard of here on Earth—cyclones take shape, travel around for awhile and then dissipate. Such behavior has left researchers scrambling to come up with a reasonable explanation for what they have observed.

Photos of the planet's north pole show that there are eight cyclones surrounding the central cyclone directly over the pole. All eight are in close proximity and all are nearly equidistant from the central cyclone—and are arranged in an octagonal pattern. At this time, it is not clear if the cyclones rotate around the center. There is a similar arrangement at the southern pole, only there are just five cyclones, shaped as a pentagon. In this new effort, the researchers have tried a new approach to explaining how it is that the cyclones hold in place for so long, and how they do it without changing their position or shape.

Vorticity and divergence derived from two independent determinations of the wind. 

Credit: Nature Astronomy (2022). DOI: 10.1038/s41550-022-01774-0

The work by the team involved analyzing pictures and other data from the Juno probe, looking specifically at wind speeds and direction. They then took what they learned and used it to create shallow water models and that led them to suggest that there is an "anticyclonic ring" of winds that move in the opposite direction of the cyclones, which is what keeps them in place. And while that may hold true, the team was unable to find signatures of convection, which would have helped to explain how heat was being used to fuel the cyclones. They acknowledge that much more work will need to be done to fully explain the behavior of Jupiter's cyclones.Ocean physics explain cyclones on Jupiter

More information: Andrew P. Ingersoll et al, Vorticity and divergence at scales down to 200 km within and around the polar cyclones of Jupiter, Nature Astronomy (2022). DOI: 10.1038/s41550-022-01774-0

Journal information: Nature Astronomy 

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