Humans need Earth-like ecosystem for deep-space living

Even on future cosmic outposts like Mars, depicted in this artistic rendering, humans must consider closely replicating natural conditions found on Earth, according to a new theory called Pancosmorio.
Illustration Credit: NASA/JPL

Can humans endure long-term living in deep space?

The answer is a lukewarm maybe, according to a new theory describing the complexity of maintaining gravity and oxygen, obtaining water, developing agriculture and handling waste far from Earth, which a Cornell researcher developed after examining the long-term physical needs of humans living far from Earth.

Dubbed the Pancosmorio theory – a word coined to mean “all world limit” – it was described in “Pancosmorio (World Limit) Theory of the Sustainability of Human Migration and Settlement in Space,” published in March in Frontiers in Astronomy and Space Sciences.

“For humans to sustain themselves and all of their technology, infrastructure and society in space, they need a self-restoring, Earth-like, natural ecosystem to back them up,” said co-author Morgan Irons, a doctoral student conducting research with Johannes Lehmann, the Liberty Hyde Bailey Professor in the School of Integrative Plant Science, College of Agriculture and Life Sciences. Her work focuses on soil organic carbon persistence under Earth’s gravity and varying gravity conditions. “Without these kinds of systems, the mission fails.”

Birth of a very distant cluster of galaxies from the early Universe

This image shows the protocluster around the Spiderweb galaxy (formally known as MRC 1138-262), seen at a time when the Universe was only 3 billion years old. Most of the mass in the protocluster does not reside in the galaxies that can be seen in the centre of the image, but in the gas known as the intracluster medium (ICM). The hot gas in the ICM is shown as an overlaid blue cloud.   The hot gas was detected with the Atacama Large Millimeter/submillimeter Array (ALMA), of which ESO is a partner. As light from the cosmic microwave background –– the relic radiation from the Big Bang –– travels through the ICM, it gains energy when it interacts with the electrons in the hot gas. This is known as the Sunyaev-Zeldovich effect. By studying this effect, astronomers can infer how much hot gas resides in the ICM, and show that the Spiderweb protocluster is in the process of becoming a massive cluster held together by its own gravity. 
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Image Credit: ESO/Di Mascolo et al.; HST: H. Ford

Using the Atacama Large Millimeter/submillimeter Array (ALMA), of which ESO is a partner, astronomers have discovered a large reservoir of hot gas in the still-forming galaxy cluster around the Spiderweb galaxy — the most distant detection of such hot gas yet. Galaxy clusters are some of the largest objects known in the Universe and this result, published today in Nature, further reveals just how early these structures begin to form.

Galaxy clusters, as the name suggests, host a large number of galaxies — sometimes even thousands. They also contain a vast “intracluster medium” (ICM) of gas that permeates the space between the galaxies in the cluster. This gas in fact considerably outweighs the galaxies themselves. Much of the physics of galaxy clusters is well understood; however, observations of the earliest phases of formation of the ICM remain scarce.

Previously, the ICM had only been studied in fully-formed nearby galaxy clusters. Detecting the ICM in distant protoclusters — that is, still-forming galaxy clusters – would allow astronomers to catch these clusters in the early stages of formation. A team led by Luca Di Mascolo, first author of the study and researcher at the University of Trieste, Italy, were keen to detect the ICM in a protocluster from the early stages of the Universe. 

New Study Reveals Potential Link Between Two of Astronomy’s Most Mysterious Phenomena

Artist's conception of fast radio burst reaching Earth.
Illustration Credit: Jingchuan Yu, Beijing Planetarium

International team of scientists reports a possible correlation between gravitational waves from neutron star mergers and fast radio bursts; results could improve understanding of how some deep-space bursts occur.

The secrets of deep space may be starting to reveal themselves, as rapid advances in technology and stronger research collaborations are making it possible for astronomers to piece together cosmological clues like never before.

  In the March 27 issue of the journal Nature Astronomy, an international team of scientists shows for the first time a possible relationship between neutron star mergers and fast radio bursts (FRBs) – two of the most mysterious cosmological phenomena studied over the past two decades.

  The team, which includes researchers from UNLV, University of Western Australia (UWA), and Curtin University, reports on the observation of a deep space neutron star merger followed just 2 ½ hours later by an observed FRB. If confirmed, the correlation between the two events could unlock part of the mystery of how FRBs are generated.

  Fast radio bursts (FRBs) are millisecond-long pulses of electromagnetic radio waves that occur in deep space and produce the energy equivalent to the sun’s annual output. Most FRBs occur as one-off events, while others present as repeating bursts. Though their origins are still a bit of a mystery, the fraction of FRBs emitted as repeated bursts are likely produced by highly magnetized neutron stars known as magnetars.

Searching for life with space dust

Space dust. This piece of interplanetary dust is thought to be part of the early solar system and was found in our atmosphere, demonstrating lightweight particles could survive atmospheric entry as they do not generate much heat from friction.
Photo Credit: 2023 NASA CC-0

Following enormous collisions, such as asteroid impacts, some amount of material from an impacted world may be ejected into space. This material can travel vast distances and for extremely long periods of time. In theory this material could contain direct or indirect signs of life from the host world, such as fossils of microorganisms. And this material could be detectable by humans in the near future, or even now.

When you hear the words vacuum and dust in a sentence, you may groan at the thought of having to do the housework. But in astronomy, these words have different connotations. Vacuum of course refers to the void of space. Dust, however, means diffuse solid material floating through space. It can be an annoyance to some astronomers as it may hinder their views of some distant object. Or dust could be a useful tool to help other astronomers learn about something distant without having to leave the safety of our own planet. Professor Tomonori Totani from the University of Tokyo’s Department of Astronomy has an idea for space dust that might sound like science fiction but actually warrants serious consideration.

Surprisingly simple explanation for alien comet ‘Oumuamua’s weird orbit

An artist’s depiction of the interstellar comet ‘Oumuamua, as it warmed up in its approach to the sun and outgassed hydrogen (white mist), which slightly altered its orbit. The comet, which is most likely pancake-shaped, is the first known object other than dust grains to visit our solar system from another star.
Image Credit: NASA, ESA and Joseph Olmsted and Frank Summers of STScI

In 2017, a mysterious comet dubbed ‘Oumuamua fired the imaginations of scientists and the public alike. It was the first known visitor from outside our solar system, it had no bright coma or dust tail, like most comets, and a peculiar shape — something between a cigar and a pancake — and its small size more befitted an asteroid than a comet.

But the fact that it was accelerating away from the sun in a way that astronomers could not explain perplexed scientists, leading some to suggest that it was an alien spaceship.

Now, a University of California, Berkeley, astrochemist and a Cornell University astronomer argue that the comet’s mysterious deviations from a hyperbolic path around the sun can be explained by a simple physical mechanism likely common among many icy comets: outgassing of hydrogen as the comet warmed up in the sunlight.

What made ‘Oumuamua different from every other well-studied comet in our solar system was its size: It was so small that its gravitational deflection around the sun was slightly altered by the tiny push created when hydrogen gas spurted out of the ice.

Hunting Venus 2.0: Scientists sharpen their sights

Composite view of Venus consisting of two images from Japan's Akatsuki mission, taken at two different distances.
Image Credit: JAXA / ISAS / DARTS / Damia Bouic

With the first paper compiling all known information about planets like Venus beyond our solar system, scientists are the closest they’ve ever been to finding an analog of Earth’s “twin.” 

If they succeed in locating one, it could reveal valuable insights into Earth’s future, and our risk of developing a runaway greenhouse climate as Venus did. 

Scientists who wrote the paper began with more than 300 known terrestrial planets orbiting other stars, called exoplanets. They whittled the list down to the five most likely to resemble Venus in terms of their radii, masses, densities, the shapes of their orbits, and perhaps most significantly, distances from their stars. 

The paper, published in The Astronomical Journal, also ranked the most Venus-like planets in terms of the brightness of the stars they orbit, which increases the likelihood that the James Webb Space Telescope would get more informative signals regarding the composition of their atmospheres.

Uracil found in Ryugu samples

A conceptual image for sampling materials on the asteroid Ryugu containing uracil and niacin by the Hayabusa2 spacecraft
Image Credit: NASA Goddard/JAXA/Dan Gallagher

Samples from the asteroid Ryugu collected by the Hayabusa2 mission contain nitrogenous organic compounds, including the nucleobase uracil, which is a part of RNA.

Researchers have analyzed samples of asteroid Ryugu collected by the Japanese Space Agency’s Hayabusa2 spacecraft and found uracil—one of the informational units that make up RNA, the molecules that contain the instructions for how to build and operate living organisms. Nicotinic acid, also known as Vitamin B3 or niacin, which is an important cofactor for metabolism in living organisms, was also detected in the same samples. 

This discovery by an international team, led by Associate Professor Yasuhiro Oba at Hokkaido University, adds to the evidence that important building blocks for life are created in space and could have been delivered to Earth by meteorites. The findings were published in the journal Nature Communications.

“Scientists have previously found nucleobases and vitamins in certain carbon-rich meteorites, but there was always the question of contamination by exposure to the Earth’s environment,” Oba explained. “Since the Hayabusa2 spacecraft collected two samples directly from asteroid Ryugu and delivered them to Earth in sealed capsules, contamination can be ruled out.”

First results from ESO telescopes on the aftermath of DART’s asteroid impact

This series of images, taken with the MUSE instrument on ESO’s Very Large Telescope, shows the evolution of the cloud of debris that was ejected when NASA’s DART spacecraft collided with the asteroid Dimorphos.  The first image was taken on 26 September 2022, just before the impact, and the last one was taken almost one month later on 25 October. Over this period several structures developed: clumps, spirals, and a long tail of dust pushed away by the Sun’s radiation. The white arrow in each panel marks the direction of the Sun.  Dimorphos orbits a larger asteroid called Didymos. The white horizontal bar corresponds to 500 kilometers, but the asteroids are only 1 kilometer apart, so they can’t be discerned in these images.  The background streaks seen here are due to the apparent movement of the background stars during the observations while the telescope was tracking the asteroid pair. 
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Image Credit: ESO/Opitom et al.

Using ESO’s Very Large Telescope (VLT), two teams of astronomers have observed the aftermath of the collision between NASA’s Double Asteroid Redirection Test (DART) spacecraft and the asteroid Dimorphos. The controlled impact was a test of planetary defense, but also gave astronomers a unique opportunity to learn more about the asteroid’s composition from the expelled material.

On 26 September 2022 the DART spacecraft collided with the asteroid Dimorphos in a controlled test of our asteroid deflection capabilities. The impact took place 11 million kilometers away from Earth, close enough to be observed in detail with many telescopes. All four 8.2-metre telescopes of ESO’s VLT in Chile observed the aftermath of the impact, and the first results of these VLT observations have now been published in two papers.

”Asteroids are some of the most basic relics of what all the planets and moons in our Solar System were created from,” says Brian Murphy, a PhD student at the University of Edinburgh in the UK and co-author of one of the studies. Studying the cloud of material ejected after DART’s impact can therefore tell us about how our Solar System formed. “Impacts between asteroids happen naturally, but you never know it in advance,” continues Cyrielle Opitom, an astronomer also at the University of Edinburgh and lead author of one of the articles. “DART is a really great opportunity to study a controlled impact, almost as in a laboratory.”

‘Terminator zones’ on distant planets could harbor life

Some exoplanets have one side permanently facing their star while the other side is in perpetual darkness. The ring-shaped border between these permanent day and night regions is called a “terminator zone.” In a new paper in The Astrophysical Journal, physics and astronomy researchers at UC Irvine say this area has the potential to support extraterrestrial life.
Illustration Credit: Ana Lobo / University of California, Irvine

In a new study, University of California, Irvine astronomers describe how extraterrestrial life has the potential to exist on distant exoplanets inside a special area called the “terminator zone,” which is a ring on planets that have one side that always faces its star and one side that is always dark.

“These planets have a permanent day side and a permanent night side,” said Ana Lobo, a postdoctoral researcher in the UCI Department of Physics & Astronomy who led the new work, which was just published in The Astrophysical Journal. Lobo added that such planets are particularly common because they exist around stars that make up about 70 percent of the stars seen in the night sky – so-called M-dwarf stars, which are relatively dimmer than our sun.

The terminator is the dividing line between the day and night sides of the planet. Terminator zones could exist in that “just right” temperature zone between too hot and too cold.

“You want a planet that’s in the sweet spot of just the right temperature for having liquid water,” said Lobo, because liquid water, as far as scientists know, is an essential ingredient for life.

On the dark sides of terminator planets, perpetual night would yield plummeting temperatures that could cause any water to be frozen in ice. The side of the planet always facing its star could be too hot for water to remain in the open for long.

Scientists have new tool to estimate how much water might be hidden beneath a planet’s surface

Exoplanets similar to Earth, artist concept.
Image Credit: NASA

Scientists from the University of Cambridge now have a way to estimate how much water a rocky planet can store in its subterranean reservoirs. It is thought that this water, which is locked into the structure of minerals deep down, might help a planet recover from its initial fiery birth.

The researchers developed a model that can predict the proportion of water-rich minerals inside a planet. These minerals act like a sponge, soaking up water which can later return to the surface and replenish oceans. Their results could help us understand how planets can become habitable following intense heat and radiation during their early years.

Planets orbiting M-type red dwarf stars — the most common star in the galaxy — are thought to be one of the best places to look for alien life. But these stars have particularly tempestuous adolescent years — releasing intense bursts of radiation that blast nearby planets and bake off their surface water.

Could Space Dust Help Protect the Earth from Climate Change?

Illustration Credit: Ben Bromley/University of Utah

On a cold winter day, the warmth of the Sun is welcome. Yet as humanity emits more greenhouse gases, the Earth's atmosphere traps more and more of the Sun's energy, which steadily increases the Earth's temperature. One strategy for reversing this trend is to intercept a fraction of sunlight before it reaches our planet.

For decades, scientists have considered using screens or other objects to block just enough of the Sun’s radiation — between 1 or 2 percent — to mitigate the effects of global warming. Now, a new study led by scientists at the Center for Astrophysics | Harvard & Smithsonian and the University of Utah explores the potential of using dust to shield sunlight.

The paper, published today in the journal PLOS Climate, describes different properties of dust particles, quantities of dust and the orbits that would be best suited for shading Earth. The team found that launching dust from Earth to a way station at the "Lagrange Point" between Earth and the Sun would be most effective but would require an astronomical cost and effort.

The team proposes moondust as an alternative, arguing that lunar dust launched from the Moon could be a low-cost and effective way to shade the Earth.

Simulations show aftermath of black hole collision

New simulations of two black holes colliding near the speed of light reveal the mysterious physics of what one astrophysicist calls "one of the most violent events you can imagine in the universe."

"It's a bit of a crazy thing to blast two black holes head-on very close to the speed of light," said Thomas Helfer, a postdoctoral fellow at Johns Hopkins University who produced the simulations. "The gravitational waves associated with the collision might look anticlimactic, but this is one of the most violent events you can imagine in the universe."

The work, which appears today in Physical Review Letters, is the first detailed look at the aftermath of such a cataclysmic clash, and shows how a remnant black hole would form and send gravitational waves through the cosmos.

Black hole mergers are one of the few events in the universe energetic enough to produce detectable gravitational waves, which carry energy produced by massive cosmic collisions. Like ripples in a pond, these waves flow through the universe distorting space and time. But unlike waves traveling through water, they are extremely tiny, and propagate through "spacetime," the mind-bending concept that combines the three dimensions of space with the idea of time.

NASA's Chandra Discovers Giant Black Holes on Collision Course

NASA’s Chandra X-ray Observatory helped identify two pairs of dwarf galaxies on track to merge.  Dwarf galaxies, which are at least about 20 times less massive than the Milky Way, likely formed larger galaxies through collisions in the early Universe.  These newly-discovered merging dwarf galaxies can be used as analogs for more distant ones that are too faint to observe.  The dwarf galaxies are on collision courses and are found in the galaxy clusters Abell 133 and Abell 1758S.
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Image Credit: X-ray: NASA/CXC/Univ. of Alabama/M. Micic et al.; Optical: International Gemini Observatory/NOIRLab/NSF/AURA

Astronomers have discovered the first evidence for giant black holes in dwarf galaxies on a collision course. This result from NASA’s Chandra X-ray Observatory has important ramifications for understanding how the first wave of black holes and galaxies grew in the early universe.

Collisions between the pairs of dwarf galaxies identified in a new study have pulled gas towards the giant black holes they each contain, causing the black holes to grow. Eventually the likely collision of the black holes will cause them to merge into much larger black holes. The pairs of galaxies will also merge into one.

Scientists think the universe was awash with small galaxies, known as “dwarf galaxies,” several hundred million years after the big bang. Most merged with others in the crowded, smaller volume of the early universe, setting in motion the building of larger and larger galaxies now seen around the nearby universe.

Meteorite crater discovered in French winery

The “Trou du Météore": The crater at the “Domaine du Météore" winery really was caused by a meteorite impact.
Photo Credit: Frank Brenker, Goethe University Frankfurt

With the aim of creating an appealing brand, the name of the “Domaine du Météore" winery near the town of Béziers in Southern France points to a local peculiarity: one of its vineyards lies in a round, 200-meter-wide depression that resembles an impact crater. By means of rock and soil analyses, scientists led by cosmochemist Professor Frank Brenker from Goethe University Frankfurt have now established that the crater was indeed once formed by the impact of an iron-nickel meteorite. In doing so, they have disproved a scientific opinion almost 60 years old, because of which the crater was never examined more closely from a geological perspective.

Countless meteorites have struck Earth in the past and shaped the history of our planet. It is assumed, for example, that meteorites brought with them a large part of its water. The extinction of the dinosaurs might also have been triggered by the impact of a very large meteorite. 

Meteorite craters that are still visible today are rare because most traces of the celestial bodies have long since disappeared again. This is due to erosion and shifting processes in the Earth's crust, known as plate tectonics. The “Earth Impact Database" lists just 190 such craters worldwide. In the whole of Western Europe, only three were previously known: Rochechouart in Aquitaine, France, the Nördlinger Ries between the Swabian Alb and the Franconian Jura, and the Steinheim Basin near Heidenheim in Baden-Württemberg (both in Germany). Thanks to millions of years of erosion, however, for laypersons the three impact craters are hardly recognizable as such.

On the track of the big bang: The most sensitive detector for measuring radioactivity is now in dresden

Prof. Kai Zuber (right) and Steffen Turkat
Photo Credit: Courtesy of Technische Universität Dresden

The "Felsenkeller" underground laboratory in Dresden now hosts the most sensitive setup for measuring radioactivity in Germany and one of the most sensitive setups in the world. With the new detector, researchers at the Technische Universität Dresden and the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) will in future be working at the highest international level on some of the most exciting questions in astrophysics, such as dark matter, stars or the Big Bang.

What is dark matter? What are neutrinos all about? How do stars work and what was actually going on in the universe in the first minutes after the Big Bang? To answer these questions, you need very sensitive detectors and a lot of skill. Only a few laboratories in the world have been able to perform such sensitive measurements so far. Recently, however, an ultra-sensitive detector has been set up in Germany, which will enable researchers to find answers to these questions in the future.

After long development work, researchers from the Institute for Nuclear and Particle Physics (Technische Universität Dresden) and the Institute for Radiation Physics (HZDR) have now put the setup into operation in the underground laboratory "Felsenkeller" Dresden. From now on, they will be able to analyze samples of substances and materials with radioactivity in the range of 100 microbequerels, in other words, samples with 100 million times less radioactivity than is present in the human body. This puts the measurement setup in the Felsenkeller laboratory among the world's most sensitive measuring instruments for radioactivity.

Unknown class of water-rich asteroids identified

Dwarf planet Ceres.
Image Credit: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / Justin Cowart

Small planets originate from the edge of our Solar System

New astronomical measurements in the infrared range have led to the identification of a heretofore unknown class of asteroids. An international research team including geoscientists from Heidelberg University has succeeded in characterizing these small planets using infrared spectroscopy. They are located in the asteroid belt between Mars and Jupiter and are – similar to the dwarf planet Ceres – rich in water. According to computer models, complex dynamic processes shifted these asteroids from the outer regions of our Solar System into today’s asteroid belt shortly after their creation.

With an equatorial diameter of approximately 900 kilometers, the dwarf planet Ceres is the largest object in the asteroid belt between Mars and Jupiter. Many other small planets orbit in this region as well. “These are the remains of the building materials from which the planets of our Solar System were created four and a half billion years ago. In these small bodies and their fragments, the meteorites, we find numerous relics that point directly to the process of planet formation,” explains Prof. Dr Mario Trieloff from the Institute of Earth Sciences of Heidelberg University. The current study shows that the small astronomical bodies originate from all regions of the early Solar System. By means of small bodies from the outer Solar System, water could have reached the still growing Earth in the form of asteroids, because the building blocks of the planets in the inner Solar System tended to be arid, according to Prof. Trieloff, who heads up the Geo- and Cosmochemistry research group.

Scientists find first observational evidence linking black holes to dark energy

Artist’s impression of a supermassive black hole. Cosmological coupling allows black holes to grow in mass without consuming gas or stars.
Image Credit: UH Manoa

Searching through existing data spanning 9 billion years, a University of Michigan physicist and colleagues have uncovered the first evidence of “cosmological coupling”—a newly predicted phenomenon in Einstein’s theory of gravity, possible only when black holes are placed inside an evolving universe.

Gregory Tarlé, U-M professor of physics, and researchers from the University of Hawaii and other institutions across nine countries studied supermassive black holes at the heart of ancient and dormant galaxies to develop a description of them that agrees with observations from the past decade. Their findings are published in two journal articles, one in The Astrophysical Journal and the other in The Astrophysical Journal Letters.

The first study found that these black holes gain mass over billions of years in a way that can’t easily be explained by standard galaxy and black hole processes, such as mergers or accretion of gas. According to the second paper, the growth in mass of these black holes matches predictions for black holes that not only cosmologically couple, but also enclose vacuum energy—material that results from squeezing matter as much as possible without breaking Einstein’s equations, thus avoiding a singularity.

Four classes of planetary systems

Artist impression of the four classes of planetary system architecture. A new architecture framework allows researchers to study an entire planetary system at the systems level. If the small planets within a system are close to the star and massive planets further away, such systems have ‘Ordered’ architecture. Conversely, if the mass of the planets in a system tends to decrease with distance to the star these systems are ‘Anti-Ordered’. If all planets in a system have similar masses, then the architecture of this system is ‘Similar’. ‘Mixed’ planetary systems are those in which the planetary masses show large variations. Research suggests that planetary systems which have the same architecture class have common formation pathways.
Illustration Credit: © NCCR PlanetS / Tobias Stierli

Astronomers have long been aware that planetary systems are not necessarily structured like our solar system. Researchers from the Universities of Bern and Geneva, as well as from the National Centre of Competence in Research PlanetS, have now shown for the first time that there are in fact four types of planetary systems. This classification will allow scientists to study planetary systems as a whole and to compare them with other systems. The results can be found in the journal Astronomy and Astrophysics.

In our solar system, everything seems to be in order: The smaller rocky planets, such as Venus, Earth or Mars, orbit relatively close to our star. The large gas and ice giants, such as Jupiter, Saturn or Neptune, on the other hand, move in wide orbits around the sun. In two studies published in the scientific journal Astronomy & Astrophysics, researchers from the Universities of Bern and Geneva and the National Centre of Competence in Research (NCCR) PlanetS show that our planetary system is quite unique in this respect. 

Spokes move along Saturn's rings

Spokes move along Saturn's rings
Seven Hubble Space Telescope images, each taken about four minutes apart, are stitched together to show "spoke" features rotating around Saturn. The puzzling, transient features have defied easy characterization. Their rotation rate does not quite match up with the rotation of the rings or of the planet's magnetic field. The spokes are known to appear during the period leading up to and following the planet's equinox. With the northern hemisphere autumnal equinox approaching on May 6, 2025, scientists are hoping new observations by Hubble will help them to put the clues together and solve the spoke mystery—what are they, and why do they form? Hubble observations will be compared with those made by NASA's Cassini spacecraft in the period surrounding Saturn's last equinox, in 2009. With the Cassini mission completed, Hubble's annual observations of Saturn as part of its Outer Planet Atmospheres Legacy (OPAL) program will be crucial to studying and better understanding this dynamic world.
Credits: SCIENCE: NASA, ESA, Amy Simon (NASA-GSFC) ANIMATION: Alyssa Pagan (STScI)

New images of Saturn from NASA's Hubble Space Telescope herald the start of the planet's "spoke season" surrounding its equinox, when enigmatic features appear across its rings. The cause of the spokes, as well as their seasonal variability, has yet to be fully explained by planetary scientists.

Like Earth, Saturn is tilted on its axis and therefore has four seasons, though because of Saturn's much larger orbit, each season lasts approximately seven Earth years. Equinox occurs when the rings are tilted edge-on to the Sun. The spokes disappear when it is near summer or winter solstice on Saturn. (When the Sun appears to reach either its highest or lowest latitude in the northern or southern hemisphere of a planet.) As the autumnal equinox of Saturn's northern hemisphere on May 6, 2025, draws near, the spokes are expected to become increasingly prominent and observable.

Breakthrough laboratory confirmation of key theory behind the formation of planets, stars and supermassive black holes

Pillars of Creation: By combining images of the iconic Pillars of Creation from two cameras aboard NASA’s James Webb Space Telescope, the universe has been framed in its glory. The pillars are the vast clouds of dust and gas in the foreground that swirl around and form celestial bodies. 
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Photo Credit: JWST/NASA

The first laboratory realization of the longstanding but never-before confirmed theory of the puzzling formation of planets, stars and supermassive black holes by swirling surrounding matter has been produced at the Princeton Plasma Physics Laboratory (PPPL). This breakthrough confirmation caps more than 20 years of experiments at PPPL, which is based at Princeton University.

The puzzle arises because matter orbiting around a central object does not simply fall into it, due to what is called the conservation of angular momentum that keeps planets and the rings of Saturn from tumbling from their orbits. That’s because the outward centrifugal force balances out the inward pull of gravity on the orbiting matter. However, the clouds of dust and plasma called accretion disks that swirl around and collapse into celestial bodies do so in defiance of the conservation of angular momentum.    

The solution to this puzzle, a theory known as the Standard Magnetorotational Instability (SMRI), was first proposed in 1991 by University of Virginia theorists Steven Balbus and John Hawley. They built on the fact that in a fluid that conducts electricity, whether the fluid be plasma or liquid metal, magnetic fields behave like springs connecting different sections of the fluid. This allows ubiquitous Alfvén waves, named after Nobel Prize winner Hannes Alfvén, to create a turbulent back-and-forth force between the inertia of the swirling fluid and the springiness of the magnetic field, causing angular momentum to be transferred between different sections of the disk.