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 

© 2022 Science X Network

No one in physics dares say so, but the race to invent new particles is pointless

In private, many physicists admit they do not believe the particles they are paid to search for exist – they do it because their colleagues are doing it

‘The Large Hadron Collider (LHC) hasn’t seen any of the particles theoretical physicists have hypothesised, even though many were confident it would.’ A technician works on the LHC, near Geneva, Switzerland. Photograph: Laurent Gilliéron/AP

Sabine Hossenfelder

THE GUARDIAN
Mon 26 Sep 2022

Imagine you go to a zoology conference. The first speaker talks about her 3D model of a 12-legged purple spider that lives in the Arctic. There’s no evidence it exists, she admits, but it’s a testable hypothesis, and she argues that a mission should be sent off to search the Arctic for spiders.

The second speaker has a model for a flying earthworm, but it flies only in caves. There’s no evidence for that either, but he petitions to search the world’s caves. The third one has a model for octopuses on Mars. It’s testable, he stresses.

Kudos to zoologists, I’ve never heard of such a conference. But almost every particle physics conference has sessions just like this, except they do it with more maths. It has become common among physicists to invent new particles for which there is no evidence, publish papers about them, write more papers about these particles’ properties, and demand the hypothesis be experimentally tested. Many of these tests have actually been done, and more are being commissioned as we speak. It is wasting time and money.

Since the 1980s, physicists have invented an entire particle zoo, whose inhabitants carry names like preons, sfermions, dyons, magnetic monopoles, simps, wimps, wimpzillas, axions, flaxions, erebons, accelerons, cornucopions, giant magnons, maximons, macros, wisps, fips, branons, skyrmions, chameleons, cuscutons, planckons and sterile neutrinos, to mention just a few. We even had a (luckily short-lived) fad of “unparticles”.

All experiments looking for those particles have come back empty-handed, in particular those that have looked for particles that make up dark matter, a type of matter that supposedly fills the universe and makes itself noticeable by its gravitational pull. However, we do not know that dark matter is indeed made of particles; and even if it is, to explain astrophysical observations one does not need to know details of the particles’ behaviour. The Large Hadron Collider (LHC) hasn’t seen any of those particles either, even though, before its launch, many theoretical physicists were confident it would see at least a few.

Talk to particle physicists in private, and many of them will admit they do not actually believe those particles exist. They justify their work by claiming that it is good practice, or that every once in a while one of them accidentally comes up with an idea that is useful for something else. An army of typewriting monkeys may also sometimes produce a useful sentence. But is this a good strategy

Experimental particle physicists know of the problem, and try to distance themselves from what their colleagues in theory development do. At the same time, they profit from it, because all those hypothetical particles are used in grant proposals to justify experiments. And so the experimentalists keep their mouths shut, too. This leaves people like me, who have left the field – I now work in astrophysics – as the only ones able and willing to criticise the situation.

There are many factors that have contributed to this sad decline of particle physics. Partly the problem is social: most people who work in the field (I used to be one of them) genuinely believe that inventing particles is good procedure because it’s what they have learned, and what all their colleagues are doing.

But I believe the biggest contributor to this trend is a misunderstanding of Karl Popper’s philosophy of science, which, to make a long story short, demands that a good scientific idea has to be falsifiable. Particle physicists seem to have misconstrued this to mean that any falsifiable idea is also good science.

In the past, predictions for new particles were correct only when adding them solved a problem with the existing theories. For example, the currently accepted theory of elementary particles – the Standard Model – doesn’t require new particles; it works just fine the way it is. The Higgs boson, on the other hand, was required to solve a problem. The antiparticles that Paul Dirac predicted were likewise necessary to solve a problem, and so were the neutrinos that were predicted by Wolfgang Pauli. The modern new particles don’t solve any problems.

In some cases, the new particles’ task is to make a theory more aesthetically appealing, but in many cases their purpose is to fit statistical anomalies. Each time an anomaly is reported, particle physicists will quickly write hundreds of papers about how new particles allegedly explain the observation. This behaviour is so common they even have a name for it: “ambulance-chasing”, after the anecdotal strategy of lawyers to follow ambulances in the hope of finding new clients.

Ambulance-chasing is a good strategy to further one’s career in particle physics. Most of those papers pass peer review and get published because they are not technically wrong. And since ambulance-chasers cite each other’s papers, they can each rack up hundreds of citations quickly. But it’s a bad strategy for scientific progress. After the anomaly has disappeared, those papers will become irrelevant.

This procedure of inventing particles and then ruling them out has been going on so long that there are thousands of tenured professors with research groups who make a living from this. It has become generally accepted practice in the physics community. No one even questions whether it makes sense.

 At least not in public.

I believe there are breakthroughs waiting to be made in the foundations of physics; the world needs technological advances more than ever before, and now is not the time to idle around inventing particles, arguing that even a blind chicken sometimes finds a grain. As a former particle physicist, it saddens me to see that the field has become a factory for useless academic papers.



Sabine Hossenfelder is a physicist at the Frankfurt Institute for Advanced Studies, Germany. She is author of Existential Physics: A Scientist’s Guide to Life’s Biggest Questions and creator of the YouTube Channel Science Without the Gobbledygook.

INSIGHT-Coal rush! Energy crisis fires global hunt for polluting fuel




* Tanzania expects thermal coal exports to double this year

* European buyers prepared to pay top dollar, miners say

* Loss of Russian energy leads to rush for polluting coal

* Landlocked Botswana also exports to Europe as prices surge

By Sudarshan Varadhan, Helen Reid, Nuzulack Dausen, Jonathan Saul and Nina Chestney

DAR ES SALAAM, Sept 20 (Reuters) - The sleepy Tanzanian port of Mtwara mainly dealt in cashew nuts until late last year. Now it bustles with vessels loading up with coal, as Russia’s invasion of Ukraine drives a worldwide race for the polluting fuel.

Tanzania traditionally exports thermal coal only to neighbouring countries in east Africa; sending it further afield was out of the question, as it required trucking the material more than 600 km from mines in its southwest to Mtwara, the nearest Indian Ocean port.

Europe’s crippling energy crisis has changed all that.

Prices for thermal coal, used to generate electricity, have leapt to record levels as a result of the war, which has led to many European countries losing access to vital supplies of natural gas and coal from their top provider Russia.

Buyers in Europe and beyond are now vying to pay top dollar for coal from often remote mines in places such as Tanzania, Botswana and even potentially Madagascar. The resurgent coal demand, driven by governments trying to wean themselves off Russian energy while keeping a lid on power prices, clashes with climate plans to shift away from the most polluting fossil fuel.

“European players, after the Russian war, are going to any place where there is coal,” Rizwan Ahmed, managing director of coal miner Bluesky Minings said in Dar es Salaam, Tanzania. “They are offering to pay very good prices.”

Commodities trader Cargill has seen a marked rise in coal shipments into Europe in recent months, said Jan Dieleman, president of Cargill’s ocean transportation division, with the company transporting 9 million tonnes of coal globally in the June-August period compared with 7 million a year earlier.

“Europe is competing with other buyers and the alternative is more expensive, which is gas,” said Dieleman. “Europe should be able to source coal and we will see very strong flows into Europe from Colombia, South Africa and even further away.”

Even though the window of opportunity may be short should the geopolitical winds shift, some countries with coal resources see the margins to be gained as too good a chance to miss.

Front-month physical thermal coal at Australia’s Newcastle port - a global benchmark - was trading at $429 a tonne on Sept. 16, just below an all-time high of $483.50 in March and up from around $176/tonne this time last year.

Mtwara has seen 13 vessels load up with coal since November last year when it launched its first-ever coal shipment, according to a port official; the latest, the MV Miss Simona, a bulk carrier with 34,529-tonne capacity, docked last week, loaded up and sailed off to France.

Since the end of June, 57 cargo orders - requests for available vessels - to ship Tanzanian coal have been seen on the spot freight market compared with just two in the same period last year, according to analysis from maritime and commodities data platform Shipfix.

Global seaborne thermal coal imports reached 97.8 million tonnes in July, the highest level on record and up more than 9% year-on-year, an analysis from ship broker Braemar shows. The volume dropped to 89 million tonnes in August, largely due to export disruptions from major producer Australia.

A LAST HURRAH FOR COAL?

Tanzania expects coal exports to double this year to around 696,773 tonnes, the country’s Mining Commission told Reuters, while production is expected to increase by 50% to about 1,364,707 tonnes.

Targeting sizeable tax revenues from this jump in exports, the government is considering building a railway that would link the coal-producing Ruvuma region to Mtwara, said Yahya Semamba, acting executive secretary of the Mining Commission, a government body.

Tanzania-based miner Ruvuma Coal has already exported at least 400,000 tonnes of coal via a trader to countries including the Netherlands, France and India since November, according to trade data reviewed by Reuters.

Ruvuma Coal declined to comment for this story.

Coal miners are enjoying unprecedented profit margins in what some see as a last hurrah for an industry facing intense pressure to cut production; with coal at $75 a tonne in late 2020, a coal mine might earn a cash margin of $15/tonne, said Rob West, analyst at consultancy Thunder Said Energy. But as prices hit $400/tonne, the cash margin increased to $235/tonne.

Indeed traders in Europe are willing to pay twice the price quoted by Asian buyers, according to some mine executives such as Bluesky’s Ahmed, who said his company didn’t currently export through Mtwara, but planned to do so, and had received requests from buyers in Germany, Poland and Britain.

Similarly, in landlocked Botswana, selling coal on the seaborne market used to be unthinkable, with most exports going to neighbouring South Africa, Namibia and Zimbabwe.

“Earlier, the logistics would kill us. However, at current prices, we can make this thing work,” said Morné du Plessis, CEO of Botswana-based coal miner Minergy.

Minergy has exported two shipments of around 30,000 tonnes each from Namibia’s Walvis Bay port, and sent two trains of coal to be exported from Mozambique’s Maputo port.

The island nation of Madagascar, the world’s top exporter of vanilla, could become another newbie on the global coal scene.

“The current prices comfortably support a business case for coal miners in Madagascar to start exporting coal for the first time in the country’s history,” said Prince Nyati, CEO of one of the companies developing a coal project in the country.

However, new entrants will have to ready themselves to pull back or even cease production if the market conditions become unfavourable, Nyati added.

1912

‘COAL HAS BEEN EMBRACED’

High demand and tight supplies of coal have redrawn trade routes, driving up global “deadweight tonne days” for the fossil fuel to record heights in July, according to Braemar research, referring to a measure of shipping levels in terms of fleet usage and the length of voyage

Thermal coal imports by the European Union from Australia, South Africa and Indonesia - which have traditionally supplied Asian markets - rose more than 11-fold in the four months after Russia invaded Ukraine, data from Indian consultancy Coalmint showed.

The invasion has forced EU nations to move to cut reliance on gas from Russia, which has reduced its vast supplies to the region. The bloc’s ban on Russian coal imports has further increased pressure on electricity generators to find alternative sources of the fuel.

Russia usually provides about 70% of the EU’s thermal coal, according to the Brussels-based think-tank Bruegel, while it typically supplies 40% of the bloc’s natural gas.

European countries have temporarily set aside environmental goals as they seek to stockpile the fuel and reopen mothballed coal plants to prepare for what could be a difficult winter.

“Strong incentives have pushed coal and lignite generation 25% above year-ago levels, despite a whole host of plant closures over the past three years,” analysts at Bank of America said about Europe.

The current ramp-up in thermal coal combustion could put countries on a collision course with ambitious CO2 emissions reduction goals; in the EU, burning more coal will increase CO2 emissions by 1.3% a year if Russian gas supplies are completely halted, according to energy think-tank Ember.

Governments in Europe say this is a temporary change, although that could depend on how long the energy crisis drags on. Germany is delaying planned shutdowns of some coal plants in order to ensure security of power supply.

Minergy, the Botswana coal miner, sees the coal market remaining strong until at least mid-2023, if not longer. It hopes to double its production capacity.

“The negative narrative surrounding coal has been abandoned, and coal has been embraced as the go-to energy source in the energy crises arising from the war,” the company said.

Reporting by Nuzulack Dausen in Dar Es Salaam, Sudarshan Varadhan in New Delhi, Helen Reid in Johannesburg, Jonathan Saul and Nina Chestney in London; Editing by Veronica Brown and Pravin Char

The Jackson Water Crisis Is a Disaster Created by Austerity

Jackson, Mississippi’s water crisis is an omen of climate disasters to come. But August floods were only the straw that broke the Jackson water system’s back. More fundamentally, the crisis is the result of decades of disinvestment and austerity.

The Salvation Army of Jackson and Walmart distribute bottled water in

 Jackson, Mississippi on August 31, 2022. (Brad Vest / Getty Images)

BY  RYAN ZICKGRAF

JACOBIN
09.06.2022

After a crisis which left 150,000 residents without drinking water for weeks, water pressure in Jackson, Mississippi is back as of Monday. But safe, clean drinking water remains elusive, and it’s unclear when that will change.

The head of the Federal Emergency Management Agency (FEMA) says it’s still too soon to declare the crisis over, and the city warned of “additional challenges” on the horizon. Jackson residents are still under the same boil-water advisory implemented in late July. For over a month, faucets have gushed a cloudy, discolored liquid that’s unsafe for drinking and cooking. Health officials told residents they could take a shower with the tainted water — albeit with mouths shut so as not to swallow it accidentally.

“It’s like we’re living in a nightmare right now,” a local high school sophomore told CNN.

The crisis was kicked off when heavy rain flooded the Pearl River and knocked out the pumps at Jackson, Mississippi’s water treatment facility for a week. Many commentators have rightly focused on climate change, identifying Jackson as a sign of disasters to come when increasingly extreme weather inevitably damages core infrastructure. But Jackson’s water problems can’t be blamed on the climate crisis alone. They’re also the result of decades of disinvestment, dysfunction, and systemic racism at every level of government.

“Deliberate Indifference”

Jackson’s mayors and city council have called for repairs on roughly fifteen hundred miles of century-old water mains off and on since the 1940s, according to Jackson’s Clarion Ledger. Back in 1978, the Environmental Protection Agency ((EPA) warned city leaders that significant improvements to the water infrastructure were needed. Yet decades of white flight and capital disinvestment from Mississippi’s capital city — now 82 percent black with a poverty rate of 25 percent — reduced the revenue officials say the water system needed to maintain full operations. An estimated $1 billion worth of necessary upgrade requests went unfulfilled.

Consequently many Jacksonians have lacked clean drinking water for years. The EPA first reported high lead levels in the city’s tap water in 2015. Since then, local officials have advised pregnant women and children under five not to drink from the tap. The lead issue has not yet been properly addressed, nor have many of the two dozen violations of the Safe Drinking Water Act that the EPA has issued over the past eight years.

Last year, two lawsuits were filed in federal court over Jackson’s lead level, with one suit alleging that the city of Jackson and the state’s Health Department made “conscience-shocking decisions and have shown deliberate indifference that has led to Plaintiffs’ exposure to toxic lead in Jackson’s drinking water.”

The lines were said to be as fragile as “peanut brittle” a year and a half ago, a time when most residents lost access to running water during back-to-back wintery storms. While the nation was panicking over the arrival of COVID-19 in February of 2020, roughly forty-three thousand Jacksonians also had to deal with losing water access for more than two weeks.

“We’ve been going it alone for the better part of two years when it comes to the Jackson water crisis,” Mayor Chokwe Antar Lumumba said. “I have said on multiple occasions that it’s not a matter of if our system would fail, but a matter of when our system would fail.”

Build Back Never?

Residents were placed under a boil-water notice in late July. August floods only exacerbated the preexisting problems, acting as the straw that broke the camel’s back.

State and federal officials have declared a state of emergency, but aren’t taking any responsibility for years of inaction as the crisis unfolded in plain sight. Last year, two bills designed to raise money for water system repairs died in the legislature. In 2020, Mississippi governor Tate Reeves, a Republican, vetoed legislation meant to assist residents struggling to pay overdue water bills, which would have in turn delivered the city much-needed revenue. Reeves instead passed the state’s largest-ever tax cut in the nation’s poorest state.

“We’re facing an environmental injustice, and we have been ignored,” said Maisie Brown, a community activist and organizer in Jackson. “Jacksonians and people around the area have been ignored by state leadership, and now they want to swoop in — all hands on deck, fixing the problem — but we’ve been asking for help for years, not even just from this administration,”

Help is coming but it’s not enough. The state is receiving $429 million from Joe Biden’s $1.2 trillion infrastructure bill for water system repairs. But that money that will be spread throughout the state and won’t begin to cover the $1 billion estimated to fix Jackson’s ailing water systems. The federal government even bungled the effort to pass out water bottles: residents were seen waiting in mile-long lines at Hawkins Field Airport for hours last Tuesday to get just one case of bottled water. When the seven hundred cases of water ran out, many Jacksonians were eventually turned away.

It’s true that Jackson’s crisis is a sign of things to come if we don’t halt climate change and ward off extreme weather. But pinning Jackson’s problems on the August floods is the equivalent of pinning the Titanic disaster on the iceberg. Jackson’s water woes aren’t an act of God. They’re a manmade disaster happening in slow motion.

This work has been made possible by the support of the Puffin Foundation.

Ryan Zickgraf is an Alabama-based journalist and is the editor of Third Rail Mag.

4 parties agree in debate - fur farms need to banned in Quebec, CAQ doesn't participate


Christine Long
CTV News Montreal Videojournalist

Updated Sept. 22, 2022

The Montreal SPCA recently hosted the first ever provincial electoral debate on animal protection, and the organization is demanding that fur farms be banned in Quebec.

At fur farms, after spending their lives in small wire cages, minks and foxes are then euthanized for their fur.

"Anal electrocutions for fox and asphyxiations for mink, these are the standard practices," said Sophie Gaillard, director of animal advocacy and legal affairs and the interim director at the Montreal SPCA.

There are three fur farms left in Quebec, and the SPCA wants them closed.

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"Over 15 countries have banned fur farming due to the inherent cruelty, and British Colombia has banned mink farming." said Gaillard.

The SPCA invited the five major provincial political parties to a debate on animal protection.

Quebec Solidaire, the Conservative Party of Quebec, the Parti Quebecois (PQ) and the Liberal party participated, and all agreed that fur farming has to end.

"Amazing all four parties committed to banning fur farming in Quebec," said Gaillard.

However, the party that didn't show is the one most likely to be in power again after Oct. 3.

"The CAQ did not take us up on our invitation," said Gaillard.

Veterinarian Dr. Marion Demarchelais says fur farming is out of date.

"It's not compatible with the animal welfare standards in 2022," she said.

Her letter of support for the SPCA says that in both life and death, the code of practices still in effect in Quebec allows these animals to be mistreated.

"All the time they are being handled with gloves and other retraining devices is highly stressful, like terrifying," said Desmarchelais. "Both the SPCA and this veterinarian agree that whoever is in power -- fur farms have to be banned."

 
RELATED IMAGES


Minks on a conveyor belt to be skinned, at Sydvestjysk Pelscenter A.m.b.a. in Varde, Denmark, Saturday, Nov. 7, 2020. 200 More than a quarter million Danes have gone into lockdown in a northern region of the country where a mutated variation of the coronavirus has infected minks being farmed for their fur, leading to an order to kill millions of the animals. Prime Minister Mette Frederiksen said Friday's move was contain the virus, and it came two days after the government ordered the cull of all 15 million minks bred at Denmark’s 1,139 mink farms. (John Randeris/Ritzau Scanpix via AP)