Astronomy

NASA will talk about the delayed return to Earth of Boeing's Starliner capsule during a press conference today (June 18), and you can listen to it live.

Europe’s newest rocket soon launches, taking with it many space missions each with a unique objective, destination and team at home, cheering them on. Whether into Earth orbit to look back and study Earth, peer out to deep space or test important new technologies, Ariane 6’s first flight will showcase the versatility and flexibility of this impressive, heavy-lift launcher. Read on for all about Curium One, then see who else is flying first.

There are so many Russian landmines across Ukraine that removing them could take 700 years. To prioritise areas for de-mining, the Ukrainian government has turned to an artificial intelligence model that can identify the most important regions

There are so many Russian landmines across Ukraine that removing them could take 700 years. To prioritise areas for de-mining, the Ukrainian government has turned to an artificial intelligence model that can identify the most important regions

Astronomers have discovered thousands of exoplanets, revealing entirely new types of worlds that we don’t have in the Solar System. It is enough to start getting a rough sense of what kinds of planets are out there. What’s the big picture?

Jupiter’s Great Red Spot (GRS) is one of the Solar System’s defining features. It’s a massive storm that astronomers have observed since the 1600s. However, its date of formation and longevity are up for debate. Have we been seeing the same phenomenon all this time?

The GRS is a gigantic anti-cyclonic (rotating counter-clockwise) storm that’s larger than Earth. Its wind speeds exceed 400 km/h (250 mp/h). It’s an icon that humans have been observing since at least the 1800s, possibly earlier. Its history, along with how it formed, is a mystery.

Its earliest observations may have been in 1632 when a German Abbott used his telescope to look at Jupiter. 32 years later, another observer reported seeing the GRS moving from east to west. Then, in 1665, Giovanni Cassini examined Jupiter with a telescope and noted the presence of a storm at the same latitude as the GRS. Cassini and other astronomers observed it continuously until 1713 and he named it the Permanent Spot.

Unfortunately, astronomers lost track of the spot. Nobody saw the GRS for 118 years until astronomer S. Schwabe observed a clear structure, roughly oval and at the same latitude as the GRS. Some think of that observation as the first observation of the current GRS and that the storm formed again at the same latitude. But the details fade the further back in time we look. There are also questions about the earlier storm and its relation to the current GRS.

New research in Geophysical Research Letters combined historical records with computer simulations of the GRS to try to understand this chimerical meteorological phenomenon. Its title is “The Origin of Jupiter’s Great Red Spot,” and the lead author is Agustín Sánchez-Lavega. Sánchez-Lavega is a Professor of Physics at the University of the Basque Country in Bilbao, Spain. He’s also head of the Planetary Sciences Group and the Department of Applied Physics at the University.

“Jupiter’s Great Red Spot (GRS) is the largest and longest-lived known vortex of all solar system planets, but its lifetime is debated, and its formation mechanism remains hidden,” the authors write in their paper.

The researchers started with historical sources dating back to the mid-1600s, just after the telescope was invented. They analyzed the size, structure, and movement of both the PS and the GRS. But that’s not a simple task. “The appearance of the GRS and its Hollow throughout the history of Jupiter observations has been highly variable due to changes in size, albedo and contrast with surrounding clouds,” they write.

This figure from the research compares the Permanent Spot (PS) and the current GRS. a, b, and c are drawings by Cassini from 1677, 1690, and 1691, respectively. d is a current 2023 image of the GRS. Image Credit: Sánchez-Lavega et al. 2024.

“From the measurements of sizes and movements we deduced that it is highly unlikely that the current GRS was the PS observed by G. D. Cassini. The PS probably disappeared sometime between the mid-18th and 19th centuries, in which case we can say that the longevity of the Red Spot now exceeds 190 years at least,” said lead author Sánchez-Lavega. The GRS was 39,000 km long in 1879 and has shrunk to 14,000 km since then. It’s also become more rounded.

Four views of Jupiter and its GRS. a is a drawing of the Permanent Spot by G. D. Cassini from 19 January 1672. b is a drawing by S. Swabe from 10 May 1851. It shows the GRS area as a clear oval with limits marked by its Hollow (drawn by a red dashed line). c is a Photograph by A. A. Common from 1879. d is a photograph from Observatory Lick with a yellow filter on 14 October 1890. Each image is an astronomical image of Jupiter with south up and east down. Image Credit: Sánchez-Lavega et al. 2024.

The historical record is valuable, but we have different tools at our disposal now. Space telescopes and spacecraft have studied the GRS in ways that would’ve been unimaginable to Cassini and others. NASA’s Voyager 1 captured our first detailed image of the GRS in 1979, when it was just over 9,000,000 km from Jupiter.

Jupiter’s Great Red Spot as imaged by Voyager 1 in 1979. The intricate wave patterns were unseen until this image. Image Credit: By NASA – http://photojournal.jpl.nasa.gov/catalog/PIA00014, Public Domain, https://commons.wikimedia.org/w/index.php?curid=86812

Since Voyager’s image, the Galileo and Juno spacecraft have both imaged the GRS. Juno, in particular, has given us more detailed images and data on Jupiter and the GRS. It captured images of the planet from only 8,000 km above the surface. Juno takes raw images of the planet with its Junocam, and NASA invites anyone to process the images, leading to artful images of the GRS like the one below.

A different take on Jupiter and its GRS. Image Credit: NASA / SwRI / MSSS / Navaneeth Krishnan S © CC BY

Juno also measured the depth of the GRS, something previous efforts couldn’t achieve. Recently, “various instruments on board the Juno mission in orbit around Jupiter have shown that the GRS is shallow and thin when compared to its horizontal dimension, as vertically it is about 500 km long,” explained Sánchez-Lavega.

Jupiter’s atmosphere contains winds running in opposite directions at different latitudes. North of the GRS, winds blow in a westerly direction and reach speeds of 180 km/h. South of the GRS, the winds flow in the opposite direction at speeds of 150 km/h. These winds generate a powerful wind shear that fosters the vortex.

In their supercomputer simulations, the researchers examined different forces that could produce the GRS in these circumstances. They considered the eruption of a gigantic superstorm like the kind that happens, though rarely, on Saturn. They also examined the phenomenon of smaller vortices created by the wind shear that merged together to form the GRS. Both of those produced anti-cyclonic storms, but their shapes and other properties didn’t match the current GRS.

“From these simulations, we conclude that the super-storm and the mergers mechanisms, although they generate a single anticyclone, are unlikely to have formed the GRS,” the researchers write in their paper.

The authors also point out that if either of these had happened, we should’ve seen them. “We also think that if one of these unusual phenomena had occurred, it or its consequences in the atmosphere must have been observed and reported by the astronomers at the time,” said Sánchez-Lavega.

However, other simulations proved more accurate in reproducing the GRS. Jupiter’s winds are known to have instabilities called the South Tropical Disturbance (STrD). When the researchers performed supercomputer simulations of the STrD, they created an anti-cyclonic storm very similar to the GRS. The STrD captured the different winds in the region and trapped them in an elongated shell like the GRS. “We therefore propose that the GRS generated from a long cell resulting from the STrD, that acquired coherence and compactness as it shrank,” the authors write.

These images from the research show how the GRS formed. a is a drawing by T. E. R. Phillips in 1931–1932 of the STrD. The red arrows indicate the flow direction with the longitude scale indicated. b and c are maps drawn from images taken by the New Horizons spacecraft. The yellow arrows mark position-velocity changes in the STrD. The STrD trapped winds and created a long cell that generated the Great Red Spot. Image Credit: Sánchez-Lavega et al. 2024.

The simulations show that over time, the GRS would rotate more rapidly as it shrank and became more coherent and compact until the elongated cell more closely resembled the current GRS. Since that’s what the GRS appears like now, the researchers settled on this explanation.

That process likely began in the mid-1800s when the GRS was much larger than it is now. That leads to the conclusion that the GRS is only about 150 years old.

The post The Great Red Spot Probably Formed in the Early 1800s appeared first on Universe Today.

The advent of “cumulative culture”—teaching others and passing down that knowledge—may have reached an inflection point around the time Neandertals and modern humans split from a common ancestor

The early Universe was a strange place. Early in its history—in the first quintillionth of a second—the entire cosmos was nothing more than a stunningly hot plasma. And, according to researchers at the Massachusetts Institute of Technology (MIT), this soup of quarks and gluons was accompanied by the formation of weird little primordial black holes (PHBs). It’s entirely possible that these long-vanished PHBs could have been the root of dark matter.

MIT’s David Kaiser and graduate student Elba Alonso-Monsalve suggest that such early super-charged black holes were very likely a new state of matter that we don’t see in the modern cosmos. “Even though these short-lived, exotic creatures are not around today, they could have affected cosmic history in ways that could show up in subtle signals today,” Kaiser said. “Within the idea that all dark matter could be accounted for by black holes, this gives us new things to look for.” That means a new way to search for the origins of dark matter.

Dark matter is mysterious. No one has directly observed it yet. However, its influence on regular “baryonic” matter is detectable. Scientists have many suggestions for what dark matter could be, but until they can observe it, it’s tough to tell what the stuff is, exactly. Black holes could be likely candidates. But the mass of all the observable ones isn’t enough to account for the amount of dark matter in the cosmos. However, there may be a connection to black holes after all.

Black Holes Through Cosmic Time

Most of us are familiar with the idea of at least two types of black holes: stellar-mass and supermassive. There is also a population of intermediate-mass black holes, which are rare. The stellar-mass objects form when massive stars explode as supernovae and collapse to form black holes. These exist throughout many galaxies. The supermassive ones aggregate many millions of solar masses together. They form “hierarchically” from smaller ones and exist in the hearts of galaxies. The intermediate-mass ones probably form hierarchically as well and could be a hidden link between the other two types.

An image based on a supercomputer simulation of the cosmological environment where primordial gas undergoes the direct collapse to create black holes. Credit: Aaron Smith/TACC/UT-Austin.

Black holes have formed throughout the history of the Universe. That’s why the idea of primordial black holes isn’t too much of a surprise, although they remain elusive. In their very primitive state, they’d be ultradense objects with the mass of an asteroid punched down into something the size of an atom. They probably didn’t last very long—maybe another quintillionth of a second. After formation, they either blinked out of existence or got scattered across the expanding Universe.

The Link Between Primordial Black Holes and Dark Matter

So, how could these weird PHBs affect the formation of dark matter if they winked in and out of existence so quickly? That’s where Kaiser and his student’s work come in. They suggest that as the first PHBs scattered, they somehow “tugged” on space-time and changed something that could explain dark matter. That same process could have produced even smaller black holes with a curious property called “color charge.” And, there’s a dark matter connection.

“Color charge” is a property of quarks and gluons, and it ends up gluing them together. Think of it as a “super-charge”. Kaiser and Alonso-Monsalve suggest that some of the very early PHBs had this “supercharge” in the same way as the quarks and gluons had it. If that’s true, then the earliest super-color-charged PHBs would have been an entirely new state of matter. We don’t see them around anymore because they likely evaporated a fraction of a second after they spawned. But, their existence was necessary, particularly to the formation of dark matter.

Even during their short life span, however, the earliest supercharged PHBs could have influenced a key cosmological transition: the time when the first atomic nuclei were forged. Those color-charged black holes could have affected the balance of fusing nuclei. And, they could have done it in a way that astronomers might someday detect with future measurements. Such an observation would point convincingly to primordial black holes as the root of all dark matter today.

What Were Those Early PHBs Made Of?

If those PHBs did exist, what were THEY made of? Unlike other black holes, there’s not much evidence for something like a star or another black hole that “birthed” these early ones. To figure that one out, Alonso-Monsalve and Kaiser did some exploration. They calculated the PHB formation “era” as happening just after the Big Bang. “Typical” microscopic black holes formed within this short “flash of time.” Those would have been as massive as an asteroid and as small as an atom. But, they also found that a tiny population of exponentially smaller black holes came into being. Those had the mass of a rhino and a size much smaller than a single proton.

This process probably started around one second after the Big Bang. That gave all these PBHs plenty of time to disrupt the equilibrium conditions that would have prevailed when the first nuclei began to form from the quark-gluon plasma. The super-charged black holes would have quickly evaporated. That probably happened about the time when the first atomic nuclei began to form. “These objects might have left some exciting observational imprints,” Alonso-Monsalve said. “They could have changed the balance of this versus that, and that’s the kind of thing that one can begin to wonder about.”

From Plasma to PHBs to Dark Matter

The backdrop for the formation of these short-lived black holes? The quark-gluon plasma. And, it should have a distribution of “color charge”. Kaiser and Alonso-Monsalve determined the size of an area in the plasma that could collapse to form a PBH. It turns out there wouldn’t have been much color charge in most typical black holes formed in the moment. That’s because they probably formed by absorbing a huge number of regions that had a mix of charges. Thus, they wouldn’t be “supercharged.”

But the smallest black holes would have been highly color-charged. They would have contained the maximum amount of any type of charge allowed for a black hole. And, by their formation, they could well have produced the tiniest bit of change that led to the formation of dark matter.

For More Information

Exotic Black holes Could be a Byproduct of Dark Matter
Preprint: Primordial Black Holes with QCD Color Charge

The post A New Way to Prove if Primordial Black Holes Contribute to Dark Matter appeared first on Universe Today.

The vicinity of Sagittarius A* (Sgr A*), the supermassive black hole at the Milky Way’s center, is hyperactive. Stars, gas, and dust zip around the black hole’s gravitational well at thousands of kilometers per hour. Previously, astronomers thought that only mature stars had been pulled into such rapid orbits. However, a new paper from the University of Cologne and elsewhere in Europe found that some relatively young stars are making the rounds rather than older ones, which raises some questions about the models predicting how stars form in these hyperactive regions.

Astronomers have known about the highly mobile stars surrounding Sgr A* for over thirty years now. They even have their own categorization, known as S stars. However, researchers lacked the equipment to analyze the age of some of these stars, and theories pointed to older, dimmer stars being the most likely to survive near a black hole.

But then, as it does so often with science, evidence that challenged the old and dim star theory began to pile up. Twelve years ago, researchers found an object they believed was a cloud of gas that was in the process of being eaten by Sgr A*. More recently, evidence has begun to hint that that gas cloud might surround a newly born star, known as a “Young Stellar Object” (YSO) in astronomy jargon.

Video showing the motion of stars around Sgr A*, from the corresponding author of the new paper.
Credit – Florian Peißker YouTube Channel

As Sgr A* started to receive more observational time with more powerful telescopes over the years, researchers were able to focus in on other interesting objects, the paper describes dozens of potential YSOs in the vicinity of the previously known S stars. Interestingly, they also seem to follow similar orbits.

Those orbits have the new YSOs zipping in front of the black hole at thousands of kilometers per hour, much faster than typical star formation theories allow. Maybe some intricacy of the black hole’s gravitational field is causing this dramatic motion, or maybe there is some other unknown aspect of stellar formation that can account for these fast-moving young stars, but for now, how they are formed remains a mystery.

However, the researchers made another interesting discovery as part of their work. They found that these YSOs, along with their S star counterparts, orbit in very well-defined formations. In a press release from the University of Cologne, they compare this to how bees from the same hive fly in formation when together. In this case, the black hole appears to be forcing them into this common formation, though other explanations could also account for it, and that analysis wasn’t part of the current research.

Fraser digs into the long term future of our supermassive black hole.

The pattern they formed was three-dimensional, so it wasn’t as simple as one stellar object following the orbital path of another around the black hole. However, the complexity still needs to be studied in detail, and theories that would account for this new information about orbital patterns are hard to come by.

As more telescope time on increasingly powerful systems is devoted to watching one of the most intriguing parts of our galaxy, there will be plenty of data for future astronomers to puzzle over. But for now, this is a step toward understanding the hyperactive world around Sgr A* and the world of stellar birth more generally and how extreme forces play a role in both.

Learn More:
University of Cologne – High-speed baby stars circle the supermassive black hole Sgr A* like a swarm of bees
Peißker et al. – Candidate young stellar objects in the S-cluster: Kinematic analysis of a subpopulation of the low-mass G objects close to Sgr A*
UT – Three Baby Stars Found at the Heart of the Milky Way
UT – Baby Stars Discharge “Sneezes” of Gas and Dust

Lead Image:
Image of the galactic center, including Sgr A*
Credit – NASA/JPL-Caltech/ESA/CXC/STSci

The post Baby Stars are Swarming Around the Galactic Center appeared first on Universe Today.

Cashew nut shells are a source of low-emissions biofuel, which is being tested in several ships, but it is unlikely there will be enough to make much of a dent in the industry’s emissions

Cashew nut shells are a source of low-emissions biofuel, which is being tested in several ships, but it is unlikely there will be enough to make much of a dent in the industry’s emissions

NASA's Perseverance Mars rover has been rerouted across a Red Planet dune field to reach the Marian territory known as "Bright Angel"

Extremely cold atoms that perpetually move in repeating patterns could be a promising building block for quantum computers

Extremely cold atoms that perpetually move in repeating patterns could be a promising building block for quantum computers

New research offers the most precise measurements yet of pulsating Cepheid stars, which may hold clues about the immense size and scale of our universe.

In his classic book On the Structure of Scientific Revolutions, the philosopher Thomas Kuhn posited that, for a new scientific framework to take root, there has to be evidence that doesn’t sit well within the existing framework. For over a century now, Einstein’s theory of relativity and gravity has been the existing framework. However, cracks are starting to show, and a new paper from researchers at Case Western Reserve University added another one recently when they failed to find decreasing rotational energy in galaxies even millions of light years away from the galaxy’s center.

Galaxies are known to rotate – even our solar system travels in a circle around the center of the Milky Way galaxy at around 200 km per second, though we can’t perceive any motion on human time scales. According to Newtonian dynamics, this rotational speed should slow down the farther away a star is from the center of a galaxy. However, observations didn’t support this, showing that the speed kept up no matter how far away the star is.

That led scientists to create another force impacting the speed of rotation of the farthest-out stars. Today, we commonly call it dark matter. However, scientists have also spent decades trying to puzzle out what exactly dark matter is made of and have yet to come up with a coherent theory.

Anton dives into a weird quirk of galaxy rotation.
Credit – Anton Petrov YouTube Channel

But in some cases, even the existence of dark matter as we know it doesn’t match the observational data. Dr. Tobias Mistele, a post-doc at Case, found that the rotational speed of galaxies doesn’t drop off, no matter how far out they are and no matter how long they’ve been doing so. This data flies in the face of a traditional understanding of dark matter, where its gravitational influence is felt by a “halo” surrounding the dark matter itself. Even these dark matter halos have an effective area. Dr. Mistele and his co-authors found evidence of maintained rotational speed that should be well outside the sphere of influence of any dark matter halo existing in these galaxies.

To collect this data, the authors used a favorite tool of cosmologists – gravitational lensing. They collected data on galaxies that were far away and had their light amplified by a galaxy cluster or similarly massive object that was nearer. When collecting the data, Dr. Mistele analyzed the speed of rotation of the stars in a galaxy and plotted it against the distance of those stars from the galaxy’s center. This is known as a “Tully-Fisher” relation in cosmology.

The result was an almost perfectly straight line – the rotational speed of stars in a galaxy did not seem to diminish with distance from the galaxy’s center, as both traditional Newtonian dynamics and relativity via dark matter predicted it would. So, what alternative explanations are there?

Why do galaxy rotation curves matter? Nora explains.
Credit – Nora’s Guide to the Galaxy YouTube Channel

Paper co-author Stacy McGaugh points out in a press release that one theory in physics accurately predicted the data his team had collected—the modified Newtonian Dynamics (or MOND) theory. Designed explicitly to account for things like galaxy rotations, MOND was developed in 1983 and remains controversial to this day. It struggles with things like the gravitational lensing with which the paper’s data was collected. 

That disconnect points to the need for a deeper understanding of gravity – what Kuhn called a “crisis,” which many cosmologists already believe is afflicting the discipline. While there is no current consensus on what might resolve that crisis, the evidence is mounting for the need for resolution. If we’re truly going to understand our place in the universe, we will eventually need to figure out a solution – it just might take a while.

Learn More:
CWRU – New, groundbreaking research shows that rotation curves of galaxies stay flat indefinitely, corroborating predictions of modified gravity theory as an alternative to dark matter
Mistele et al. – Indefinitely Flat Circular Velocities and the Baryonic Tully-Fisher Relation from Weak Lensing
UT – Will Wide Binaries Be the End of MOND?
UT – New Measurements of Galaxy Rotation Lean Towards Modified Gravity as an Explanation for Dark Matter
UT – The Earliest Galaxies Rotated Slowly, Revving up Over Billions of Years

Lead Image:
Illustration of the galaxy rotation curve used in the research.
Credit – Mistele et al.

The post Rotation Curves of Galaxies Stay Flat Indefinitely appeared first on Universe Today.

In the years before the JWST’s launch, astronomers’ efforts to understand the early Universe were stymied by a stubborn obstacle: the light from the early Universe was red-shifted to an extreme degree. The JWST was built with extreme redshifts in mind, and one of its goals was to study Galaxy Assembly.

Once the JWST activated its segmented, beryllium eye, the Universe’s most ancient, red-shifted light became visible.

The light emitted by the first galaxies is not only faint but has been stretched by billions of years of cosmic expansion. The galaxies that emitted that light are called high-redshift galaxies, where redshift is indicated by the letter z. Since its shifted into the red, only infrared telescopes can see it. Telescopes like the Hubble and the Spitzer can see some redshifted light. But the JWST has far more power than its predecessors, allowing it to effectively see further back in time.

“Using advanced instruments such as JWST allows us to study more distant galaxies with greater detail than ever before.”

Yicheng Guo, Department of Physics and Astronomy, University of Missouri

Observations have shown that galaxies grow large through mergers and collisions and that up to 60% of all galaxies are spirals. But how did the process play out? When did the first spirals emerge? An answer to that question trickles down and affects other outstanding questions about galaxies.

Spiral arms host active star formation, where successive generations of stars create heavier elements. Those elements allow rocky planets to form and are also a requirement for life. So, an understanding of when spiral galaxies formed helps astronomers understand the parameters of star formation, rocky planet formation, and even, potentially, the appearance of life.

“Knowing when spiral galaxies formed in the universe has been a popular question in astronomy because it helps us understand the evolution and history of the cosmos.”

Vicki Kuhn, Department of Physics and Astronomy, University of Missouri

One of the JWST’s observing efforts is CEERS, the Cosmic Evolution Early Release Science Survey. In CEERS, the JWST was the first telescope to capture images of the Universe’s early galaxies. CEERS found the most distant active supermassive black hole and galaxies that existed in the distant past when the Universe was only about 500 to 700 million years old.

Image of CEERS scientists looking at the Epoch 1 NIRCam color mosaic in TACC’s visualization lab at UT Austin. Credit: R. Larson

New research published in The Astrophysical Journal Letters examined galaxies from CEERS to determine how many of these ancient galaxies were spirals. The title is “JWST Reveals a Surprisingly High Fraction of Galaxies Being Spiral-like at 0.5 ≤ z ≤ 4.” The first author is Vicki Kuhn, a graduate student in the University of Missouri’s Department of Physics and Astronomy.

“Scientists formerly believed most spiral galaxies developed around 6 to 7 billion years after the universe formed,” said Yicheng Guo, an associate professor in Mizzou’s (University of Missouri) Department of Physics and Astronomy and co-author of the study. “However, our study shows spiral galaxies were already prevalent as early as 2 billion years afterward. This means galaxy formation happened more rapidly than we previously thought.”

In their research letter, the authors examined 873 galaxies from CEERS with redshift 0.5 ≤ z ≤ 4 and stellar mass ≤ 1010 solar masses. They found that 216 of them had spiral structures. “This fraction is surprisingly high and implies that the formation of spiral arms, as well as disks, was earlier in the Universe,” the authors write in their paper.

This figure from the research shows some of the galaxies in the sample. Redshift increases from left to right, and the rows from top to bottom show the range of galaxies classified as spiral to nonspiral. “Spiral structure is easier to see at the lower redshift ranges and becomes less pronounced at higher redshifts.” the authors write. The top three rows show galaxies identified as spirals with strong confidence, the middle three rows show galaxies identified as spirals with less confidence, and the bottom row shows non-spirals. Image Credit: Kuhn et al. 2024

“Knowing when spiral galaxies formed in the universe has been a popular question in astronomy because it helps us understand the evolution and history of the cosmos,” said lead author Kuhn. “Many theoretical ideas exist about how spiral arms are formed, but the formation mechanisms can vary amongst different types of spiral galaxies. This new information helps us better match the physical properties of galaxies with theories — creating a more comprehensive cosmic timeline.”

Spiral galaxies started as disks of gas. These results, when combined with other studies of high-redshift galaxies, paint a picture of the history of galaxy evolution in the early Universe. Dynamically hot gaseous disks appear around z = 4 to 5. These disks settled down to become dynamically cold gaseous disks around z = 3 to 4. Since stars form when gas cools and clumps together, large numbers of dynamically cold stellar disks appeared at z = 3 to 4, as indicated by their spiral arms.

This research also illuminates the relationships between spiral arms and other galaxy substructures. Gas-rich disks at high redshifts are very turbulent, and gravitational instabilities form giant clumps of star formation. Later, hot stars disperse young galaxies’ velocities, allowing them to settle down and become less turbulent. These bulges of star formation can also merge, helping to further stabilize the disks. The conclusion is that gravitational instabilities primarily lead to spiral arms, with clumps playing a secondary role since they co-exist with spirals at high redshifts.

The authors point out some caveats in their work. Galaxies that are merging can appear as spirals. The long tails prevalent during mergers can look like spiral arms, so their numbers could be off a little. But on the other hand, spirals can also look like mergers, adding to the uncertainty. “This situation is more severe for galaxies at z > 2, as the merger fraction is believed to be higher then,” the authors write.

But these facts likely don’t affect the conclusion much. “The observed spiral fraction decreases with increasing redshift, from ~43% at z = 1 to ~4% at z = 3,” the researchers conclude. So, while spirals are rarer the further we look back in time, they’re still more plentiful earlier than thought.

“Using advanced instruments such as JWST allows us to study more distant galaxies with greater detail than ever before,” Guo said. “A galaxy’s spiral arms are a fundamental feature used by astronomers to categorize galaxies and understand how they form over time. Even though we still have many questions about the universe’s past, analyzing this data helps us uncover additional clues and deepens our understanding of the physics that shaped the nature of our universe.”

The post Almost a Third of Early Galaxies Were Already Spirals appeared first on Universe Today.

The FAA is holding a virtual public meeting this evening (June 17) about the potential environmental impact of SpaceX's Starship operations in Florida, and you can participate.

Boeing Starliner has seen its one-week test mission in space double to about two weeks. That allowed time for an incredible aurora show during thruster testing on June 15.