Topic: Mid May Astronomy Bulletin

[Clive]

URANUS’ MOONS MAY HOLD WATER
NASA

Re-analysis of data from NASA’s Voyager spacecraft, along with new computer modelling, has led NASA scientists to conclude that four of Uranus’ largest moons likely contain an ocean layer between their cores and icy crusts. Their study is the first to detail the evolution of the interior makeup and structure of all five large moons: Ariel, Umbriel, Titania, Oberon, and Miranda. The work suggests four of the moons hold oceans that could be dozens of miles deep. In all, at least 27 moons circle Uranus, with the four largest ranging from Ariel, at 720 miles across, to Titania, which is 980 miles across. Scientists have long thought that Titania, given its size, would be most likely to retain internal heat, caused by radioactive decay. The other moons had previously been widely considered too small to retain the heat necessary to keep an internal ocean from freezing, especially because heating created by the gravitational pull of Uranus is only a minor source of heat. The National Academies’ 2023 Planetary Science and Astrobiology Decadal Survey prioritized exploring Uranus. In preparation for such a mission, planetary scientists are focusing on the ice giant to bolster their knowledge about the mysterious Uranus system. Published in the Journal of Geophysical Research, the new work could inform how a future mission might investigate the moons, but the paper also has implications that go beyond Uranus.

The study revisited findings from NASA’s Voyager 2 flybys of Uranus in the 1980s and from ground-based observations. The authors built computer models infused with additional findings from NASA’s Galileo, Cassini, Dawn, and New Horizons (each of which discovered ocean worlds), including insights into the chemistry and the geology of Saturn’s moon Enceladus, Pluto and its moon Charon, and Ceres – all icy bodies around the same size as the Uranian moons. The researchers used that modelling to gauge how porous the Uranian moons’ surfaces are, finding that they’re likely insulated enough to retain the internal heat that would be needed to host an ocean. In addition, they found what could be a potential heat source in the moons’ rocky mantles, which release hot liquid, and would help an ocean maintain a warm environment – a scenario that is especially likely for Titania and Oberon, where the oceans may even be warm enough to potentially support habitability. By investigating the composition of the oceans, scientists can learn about materials that might be found on the moons’ icy surfaces as well, depending on whether substances underneath were pushed up from below by geological activity. There is evidence from telescopes that at least one of the moons, Ariel, has material that flowed onto its surface, perhaps from icy volcanoes, relatively recently. In fact, Miranda, the innermost and fifth largest moon, also hosts surface features that appear to be of recent origin, suggesting it may have held enough heat to maintain an ocean at some point. The recent thermal modelling found that Miranda is unlikely to have hosted water for long: It loses heat too quickly and is probably frozen now.

But internal heat wouldn’t be the only factor contributing to a moon’s subsurface ocean. A key finding in the study suggests that chlorides, as well as ammonia, are likely abundant in the oceans of the icy giant’s largest moons. Ammonia has been long known to act as antifreeze. In addition, the modelling suggests that salts likely present in the water would be another source of antifreeze, maintaining the bodies’ internal oceans. Of course, there still are a lot of questions about the large moons of Uranus. Digging into what lies beneath and on the surfaces of these moons will help scientists and engineers choose the best science instruments to survey them. For instance, determining that ammonia and chlorides may be present means that spectrometers, which detect compounds by their reflected light, would need to use a wavelength range that covers both kinds of compounds. Likewise, they can use that knowledge to design instruments that can probe the deep interior for liquid. Searching for electrical currents that contribute to a moon’s magnetic field is generally the best way to find a deep ocean, as Galileo mission scientists did at Jupiter’s moon Europa. However, the cold water in the interior oceans of moons such as Ariel and Umbriel could make the oceans less able to carry these electrical currents and would present a new kind of challenge for scientists working to figure out what lies beneath.


45-YEAR VOYAGER 2 MISSION EXTENDED
Gizmodo

At 12 billion miles (20 billion kilometers) from Earth, Voyager 2 is so far that it takes more than 22 hours for NASA’s signals to reach the probe. With its power gradually diminishing, mission planners thought they might have to shut down one of its five scientific instruments next year, but a newly implemented plan has resulted in a welcomed delay. A recent adjustment, in which the probe redirects a tiny amount of power meant for an onboard safety system, means all five scientific instruments aboard Voyager 2 can stay active until 2026. There’s a modicum of risk involved, as the affected system protects Voyager 2 from voltage irregularities, but NASA says the probe can now keep its science instruments turned on for a while longer. Voyager 2, along with its twin companion Voyager 1, are the probes that just keep on ticking. Launched in 1977, the spacecraft visited several planets in the outer solar system before tickling the outer fringes of the heliosphere—a protective bubble-like region of space that surrounds the Sun and shields us from harmful radiation pouring in from interstellar space. The probes are still active and gathering unprecedented data about the heliosphere and its protective qualities.

Generators on both probes lose power each year as the result of a continual decay process. This hasn’t affected their science gathering, but mission planners have had to turn off heaters and other non-essential systems to compensate for the ongoing power loss. For Voyager 2, it was getting to the stage where one science instrument needed to be turned off soon—as early as next year. As a result of the newly implemented hack, Voyager 2 is now using a small amount of backup power provisioned for an onboard safety mechanism designed to protect the craft from potentially damaging voltage spikes. The probe is stealing some of this juice—not a lot—to keep all five of its science instruments on. Although the spacecraft’s voltage will not be tightly regulated as a result, even after more than 45 years in flight, the electrical systems on both probes remain relatively stable, minimizing the need for a safety net. The engineering team is also able to monitor the voltage and respond if it fluctuates too much. If the new approach works well for Voyager 2, the team may implement it on Voyager 1 as well. Voyager 1 passed the heliosphere in 2012, while its twin did the same in 2018, the gap being the result of Voyager 2’s slower speed and alternate direction. An onboard scientific instrument failed early during the Voyager 1 mission, making it less reliant on power than Voyager 2. Voltage spikes are a minor risk at this stage of the mission and the payoff—more science from Voyager 2—is worth it.



FOMALHAUT HAS ASTEROID BELT
NASA

Astronomers used the James Webb Space Telescope to image the warm dust around a nearby young star, Fomalhaut, in order to study the first asteroid belt ever seen outside of our solar system in infrared light. But to their surprise, the dusty structures are much more complex than the asteroid and Kuiper dust belts of our solar system. Overall, there are three nested belts extending out to 14 billion miles from the star; that’s 150 times the distance of Earth from the Sun. The scale of the outermost belt is roughly twice the scale of our solar system’s Kuiper Belt of small bodies and cold dust beyond Neptune. The inner belts – which had never been seen before – were revealed by Webb for the first time. The belts encircle the young hot star, which can be seen with the naked eye as the brightest star in the southern constellation Piscis Austrinus. The dusty belts are the debris from collisions of larger bodies, analogous to asteroids and comets, and are frequently described as “debris disks. The Hubble Space Telescope and Herschel Space Observatory, as well as the Atacama Large Millimeter/submillimeter Array (ALMA), have previously taken sharp images of the outermost belt. However, none of them found any structure interior to it. The inner belts have been resolved for the first time by Webb in infrared light. These belts most likely are carved by the gravitational forces produced by unseen planets. Similarly, inside our solar system Jupiter corrals the asteroid belt, the inner edge of the Kuiper Belt is sculpted by Neptune, and the outer edge could be shepherded by as-yet-unseen bodies beyond it. As Webb images more systems, we will learn about the configurations of their planets.

Fomalhaut’s dust ring was discovered in 1983 in observations made by NASA’s Infrared Astronomical Satellite (IRAS). The existence of the ring has also been inferred from previous and longer-wavelength observations using submillimeter telescopes on Mauna Kea, Hawaii, NASA’s Spitzer Space Telescope, and Caltech’s Submillimeter Observatory. The idea of a protoplanetary disk around a star goes back to the late 1700s, when astronomers Immanuel Kant and Pierre-Simon Laplace independently developed the theory that the Sun and planets formed from a rotating gas cloud that collapsed and flattened due to gravity. Debris disks develop later, following the formation of planets and dispersal of the primordial gas in the systems. They show that small bodies like asteroids are colliding catastrophically and pulverizing their surfaces into huge clouds of dust and other debris. Observations of their dust provide unique clues to the structure of an exoplanetary system, reaching down to Earth-sized planets and even asteroids, which are much too small to see individually.


SUPERFLARE WITH MASSIVE HIGH-VELOCITY ERUPTION
National Institutes of Natural Sciences

A team of Japanese astronomers used simultaneous ground-based and space-based observations to capture a more complete picture of a superflare on a star. The observed flare started with a very massive, high-velocity prominence eruption. These results give us a better idea of how superflares and stellar prominence eruptions occur. Some stars have been seen releasing superflares over 10 times larger than the largest solar flare ever seen on the Sun. The hot ionized gas released by solar flares can influence the environment around the Earth, referred to as space weather. More powerful superflares must have an even greater impact on the evolution of any planets forming around the star, or the evolution of any life forming on those planets. But the details of how superflares and prominence eruptions on stars occur have been unclear. The team used the 3.8-m Seimei Telescope in Japan and the Transiting Exoplanet Survey Satellite (TESS) to monitor the binary star system V1355 Orionis which is known to frequently release large-scale superflares. V1355 Orionis is located 400 light years away in the constellation Orion. The team succeeded in capturing a superflare with continuous, high temporal resolution observations. Data analysis shows that the superflare originated with a phenomenon known as a prominence eruption. Calculating the velocity of the eruption requires making some assumptions about aspects that aren't directly observably, but even the most conservative estimates far exceed the escape velocity of the star (347 km/s), indicating that the prominence eruption was capable of breaking free of the star's gravity and developing into Coronal Mass Ejections (CMEs). The prominence eruption was also one of the most massive ever observed, carrying trillions of tons of material.


WEBB FINDS WATER VAPOUR IN VICINITY OF RED DWARF STAR
NASA/Goddard Space Flight Center

The most common stars in the Universe are red dwarf stars, which means that rocky exoplanets are most likely to be found orbiting such a star. Red dwarf stars are cool, so a planet has to hug it in a tight orbit to stay warm enough to potentially host liquid water (meaning it lies in the habitable zone). Such stars are also active, particularly when they are young, releasing ultraviolet and X-ray radiation that could destroy planetary atmospheres. As a result, one important open question in astronomy is whether a rocky planet could maintain, or re-establish, an atmosphere in such a harsh environment. To help answer that question, astronomers used NASA's James Webb Space Telescope to study a rocky exoplanet known as GJ 486 b. It is too close to its star to be within the habitable zone, with a surface temperature of about 430 degrees Celsius. And yet, their observations using Webb's Near-Infrared Spectrograph (NIRSpec) show hints of water vapour. If the water vapour is associated with the planet, that would indicate that it has an atmosphere despite its scorching temperature and close proximity to its star. Water vapour has been seen on gaseous exoplanets before, but to date no atmosphere has been definitely detected around a rocky exoplanet. However, the team cautions that the water vapour could be on the star itself -- specifically, in cool starspots -- and not from the planet at all.

GJ 486 b is about 30% larger than Earth and three times as massive, which means it is a rocky world with stronger gravity than Earth. It orbits a red dwarf star in just under 1.5 Earth days. It is expected to be tidally locked, with a permanent day side and a permanent night side. GJ 486 b transits its star, crossing in front of the star from our point of view. If it has an atmosphere, then when it transits starlight would filter through those gasses, imprinting fingerprints in the light that allow astronomers to decode its composition through a technique called transmission spectroscopy. The team observed two transits, each lasting about an hour. They then used three different methods to analyze the resulting data. The results from all three are consistent in that they show a mostly flat spectrum with an intriguing rise at the shortest infrared wavelengths. The team ran computer models considering a number of different molecules, and concluded that the most likely source of the signal was water vapour. While the water vapour could potentially indicate the presence of an atmosphere on GJ 486 b, an equally plausible explanation is water vapor from the star. Surprisingly, even in our own Sun, water vapour can sometimes exist in sunspots because these spots are very cool compared to the surrounding surface of the star. GJ 486 b's host star is much cooler than the Sun, so even more water vapour would concentrate within its starspots. As a result, it could create a signal that mimics a planetary atmosphere. A water vapour atmosphere would be expected to gradually erode due to stellar heating and irradiation. As a result, if an atmosphere is present, it would likely have to be constantly replenished by volcanoes ejecting steam from the planet's interior. If the water is indeed in the planet's atmosphere, additional observations are needed to narrow down how much water is present.


STAR DISCOVERED DEVOURING PLANET
NASA

A new study documents the first observation of an aging star swallowing a planet. After running out of fuel in its core, the star began to grow in size, shrinking the gap with its neighbouring planet, eventually consuming it entirely. In about 5 billion years, our Sun will go through a similar aging process, possibly reaching 100 times its current diameter and becoming what’s known as a red giant. During that growth spurt, it will absorb Mercury, Venus, and possibly Earth. Astronomers have identified many red giant stars and suspected that in some cases they consume nearby planets, but the phenomenon had never been directly observed before. This type of event has been predicted for decades, but until now we have never actually observed how this process plays out. Researchers discovered the event – formally called ZTF SLRN-2020 – using multiple ground-based observatories and NASA’s NEOWISE (Near-Earth Object Wide Field Infrared Survey Explorer) spacecraft, which is managed by the agency’s Jet Propulsion Laboratory. The planet was likely about the size of Jupiter, with an orbit even closer to its star than Mercury’s is to our Sun. The star is at the beginning of the final phase of its life – its red giant phase, which can last more than 100,000 years.

As the star expanded, its outer atmosphere eventually surrounded the planet. Drag from the atmosphere slowed the planet down, shrinking its orbit and eventually sending it below the star’s visible surface, like a meteor burning up in Earth’s atmosphere. The transfer of energy caused the star to temporarily increase in size and become a few hundred times brighter. Recent observations show the star has returned to the size and brightness it was before merging with the planet. The flash of optical light after the planet’s demise showed up in observations by the Caltech-led Zwicky Transient Facility (ZTF), an instrument based at Palomar Observatory in Southern California that looks for cosmic events that change in brightness rapidly, sometimes in a matter of hours. The team was using ZTF to search for events called novae – when a dead, collapsed star (known as a white dwarf) cannibalizes hot gas from another nearby star. Novae are always surrounded by flows of hot gas, but follow-up observations of the flash by other ground-based telescopes showed much cooler gas and dust surrounding the star, meaning it didn’t look like a nova or anything else astronomers had ever seen.

So they turned to the NEOWISE observatory, which scans the entire sky in infrared light (a range of wavelengths longer than visible light) every six months. Launched in 2009 and originally called WISE, the observatory produces all-sky maps that enable astronomers to see how objects change over time. Looking at the NEOWISE data, it was seen that the star brightened almost a year before ZTF spotted the flash. That brightening was evidence of dust (which emits infrared light) forming around the star. The team think the dust indicates that the planet didn’t go down without a fight and that it pulled hot gas away from the puffy star’s surface as it spiralled toward its doom. As the gas drifted out into space, it would have cooled and become dust – like water vapour becoming snow. Even more gas was then flung into space during the collision of the star and the planet, producing more dust visible to both the ground-based infrared observatories and NEOWISE. Five billion years from now, when our Sun is expected to become a red giant, swallowing up Mercury, Venus, and possibly Earth, the light show should be much more subdued, since those planets are many times smaller than the Jupiter-size planet in the ZTF-captured event.


MASSIVE TOUCHING STARS WILL COLLIDE AS BLACK HOLES
University College London

Two massive touching stars in a neighbouring galaxy are on course to become black holes that will eventually crash together, generating waves in the fabric of space-time. The researchers found that the stars, located in a neighbouring dwarf galaxy called the Small Magellanic Cloud, are in partial contact and swapping material with each other, with one star currently "feeding" off the other. They orbit each other every three days and are the most massive touching stars (known as contact binaries) yet observed. Comparing the results of their observations with theoretical models of binary stars' evolution, they found that, in the best-fit model, the star that is currently being fed on will become a black hole and will feed on its companion star. The surviving star will become a black hole shortly after. These black holes will form in only a couple of million years, but will then orbit each other for billions of years before colliding with such force that they will generate gravitational waves -- ripples in the fabric of space-time -- that could theoretically be detected with instruments on Earth. Thanks to gravitational wave detectors Virgo and LIGO, dozens of black hole mergers have been detected in the last few years. But so far we have yet to observe stars that are predicted to collapse into black holes of this size and merge in a time scale shorter than or even broadly comparable to the age of the Universe. The best-fit model suggests these stars will merge as black holes in 18 billion years. Finding stars on this evolutionary pathway so close to our Milky Way galaxy presents us with an excellent opportunity learn even more about how these black hole binaries form.

This binary star is the most massive contact binary observed so far. The smaller, brighter, hotter star, 32 times the mass of the Sun, is currently losing mass to its bigger companion, which has 55 times our Sun's mass. The black holes that astronomers see merge today formed billions of years ago, when the Universe had lower levels of iron and other heavier elements. The proportion of these heavy elements has increased as the Universe has aged and this makes black hole mergers less likely. This is because stars with a higher proportion of heavier elements have stronger winds and they blow themselves apart sooner. The well-studied Small Magellanic Cloud, about 210,000 light years from Earth, has by a quirk of nature about a seventh of the iron and other heavy metal abundances of our own Milky Way galaxy. In this respect it mimics conditions in the Universe's distant past. But unlike older, more distant galaxies, it is close enough for astronomers to measure the properties of individual and binary stars. In their study, the researchers measured different bands of light coming from the binary star (spectroscopic analysis), using data obtained over multiple periods of time by instruments on NASA's Hubble Space Telescope (HST) and the Multi Unit Spectroscopic Explorer (MUSE) on ESO's Very Large Telescope in Chile, among other telescopes, in wavelengths ranging from ultraviolet to optical to near infrared. With this data, the team were able to calculate the radial velocity of the stars -- that is, the movement they made towards or away from us -- as well as their masses, brightness, temperature and orbits. They then matched these parameters with the best-fit evolutionary model. Their spectroscopic analysis indicated that much of the outer envelope of the smaller star had been stripped away by its larger companion. They also observed the radius of both stars exceeded their Roche lobe -- that is, the region around a star where material is gravitationally bound to that star -- confirming that some of the smaller star's material is overflowing and transferring to the companion star. The smaller star will become a black hole first, in as little as 700,000 years, either through a spectacular explosion called a supernova or it may be so massive as to collapse into a black hole with no outward explosion. They will be uneasy neighbours for around three million years before the first black hole starts accreting mass from its companion, taking revenge on its companion. After only 200,000 years, an instant in astronomical terms, the companion star will collapse into a black hole as well. These two massive stars will continue to orbit each other, going round and round every few days for billions of years.


NEARBY BLACK HOLE DEVOURING STAR
Massachusetts Institute of Technology

Once every 10,000 years or so, the centre of a galaxy lights up as its supermassive black hole rips apart a passing star. This "tidal disruption event" happens in a literal flash, as the central black hole pulls in stellar material and blasts out huge amounts of radiation in the process. Astronomers know of around 100 tidal disruption events (TDE) in distant galaxies, based on the burst of light that arrives at telescopes on Earth and in space. Most of this light comes from X-rays and optical radiation. MIT astronomers, tuning past the conventional X-ray and UV/optical bands, have discovered a new tidal disruption event, shining brightly in infrared. It is one of the first times scientists have directly identified a TDE at infrared wavelengths. What's more, the new outburst happens to be the closest tidal disruption event observed to date: The flare was found in NGC 7392, a galaxy that is about 137 million light-years from Earth, which corresponds to a region in our cosmic backyard that is one-fourth the size of the next-closest TDE. This new flare, labeled WTP14adbjsh, did not stand out in standard X-ray and optical data. The scientists suspect that these traditional surveys missed the nearby TDE, not because it did not emit X-rays and UV light, but because that light was obscured by an enormous amount of dust that absorbed the radiation and gave off heat in the form of infrared energy.

The researchers determined that WTP14adbjsh occurred in a young, star-forming galaxy, in contrast to the majority of TDEs that have been found in quieter galaxies. Scientists expected that star-forming galaxies should host TDEs, as the stars they churn out would provide plenty of fuel for a galaxy's central black hole to devour. But observations of TDEs in star-forming galaxies were rare until now. The new study suggests that conventional X-ray and optical surveys may have missed TDEs in star-forming galaxies because these galaxies naturally produce more dust that could obscure any light coming from their core. Searching in the infrared band could reveal many more, previously hidden TDEs in active, star-forming galaxies. The team did not intend to search for tidal disruption events. It was looking for signs of general transient sources in observational data, using a search tool developed by De. The team used De's method to look for potential transient events in archival data taken by NASA's NEOWISE mission, a space telescope that has made regular scans of the entire sky since 2010, at infrared wavelengths. The team discovered a bright flash that appeared in the sky near the end of 2014. They traced the flash to a galaxy 42 megarparsecs from Earth. The question then was, what set it off? To answer this, the team considered the brightness and timing of the flash, comparing the actual observations with models of various astrophysical processes that could produce a similar flash. Working through different possibilities of what the burst could be, the scientists were finally able to exclude all but one: The flash was most likely a TDE, and the closest one observed so far. from there, the researchers took a closer look at the galaxy where the TDE arose. They gathered data from multiple ground- and space-based telescopes which happened to observe the part of the sky where the galaxy resides, across various wavelengths, including infrared, optical, and X-ray bands. With this accumulated data, the team estimated that the supermassive black hole at the centre of the galaxy was about 30 million times as massive as the Sun. The team also found that the galaxy itself is actively producing new stars. Star-forming galaxies are a class of "blue" galaxies, in contrast to quieter "red" galaxies that have stopped producing new stars. Star-forming blue galaxies are the most common type of galaxy in the Universe.


DISTANT GAS CLOUDS HAVE LEFTOVERS OF FIRST STARS
ESO

Using ESO's Very Large Telescope (VLT), researchers have found for the first time the fingerprints left by the explosion of the first stars in the Universe. They detected three distant gas clouds whose chemical composition matches what we expect from the first stellar explosions. These findings bring us one step closer to understanding the nature of the first stars that formed after the Big Bang. Researchers think that the first stars that formed in the Universe were very different from the ones we see today. When they appeared 13.5 billion years ago, they contained just hydrogen and helium, the simplest chemical elements in nature. These stars, thought to be tens or hundreds of times more massive than our Sun, quickly died in powerful explosions known as supernovae, enriching the surrounding gas with heavier elements for the first time. Later generations of stars were born out of that enriched gas, and in turn ejected heavier elements as they too died. But the very first stars are now long gone, so how can researchers learn more about them? Primordial stars can be studied indirectly by detecting the chemical elements they dispersed in their environment after their death. Using data taken with ESO's VLT in Chile, the team found three very distant gas clouds, seen when the Universe was just 10-15% of its current age, and with a chemical fingerprint matching what we expect from the explosions of the first stars. Depending on the mass of these early stars and the energy of their explosions, these first supernovae released different chemical elements such as carbon, oxygen and magnesium, which are present in the outer layers of stars. But some of these explosions were not energetic enough to expel heavier elements like iron, which is found only in the cores of stars.

To search for the telltale sign of these very first stars that exploded as low energy supernovae, the team therefore looked for distant gas clouds poor in iron but rich in the other elements. And they found just that: three faraway clouds in the early Universe with very little iron but plenty of carbon and other elements -- the fingerprint of the explosions of the very first stars. This peculiar chemical composition has also been observed in many old stars in our own galaxy, which researchers consider to be second-generation stars that formed directly from the 'ashes' of the first ones. This new study has found such ashes in the early Universe, thus adding a missing piece to this puzzle. The discovery opens new avenues to indirectly study the nature of the first stars, fully complementing studies of stars in our galaxy. To detect and study these distant gas clouds, the team used light beacons known as quasars -- very bright sources powered by supermassive black holes at the centres of faraway galaxies. As the light from a quasar travels through the Universe, it passes through gas clouds where different chemical elements leave an imprint on the light. To find these chemical imprints, the team analysed data on several quasars observed with the X-shooter instrument on ESO's VLT. X-shooter splits light into an extremely wide range of wavelengths, or colours, which makes it a unique instrument with which to identify many different chemical elements in these distant clouds. This study opens new windows for next generation telescopes and instruments, like ESO's upcoming Extremely Large Telescope (ELT) and its high-resolution ArmazoNes high Dispersion Echelle Spectrograph (ANDES). "With ANDES at the ELT we will be able to study many of these rare gas clouds in greater detail, and we will be able to finally uncover the mysterious nature of the first stars. .

EARLY-UNIVERSE PREQUEL TO HUGE GALAXY CLUSTER
NASA/Goddard Space Flight Center

Every giant was once a baby, though you may never have seen them at that stage of their development. NASA's James Webb Space Telescope has begun to shed light on formative years in the history of the Universe that have thus far been beyond reach: the formation and assembly of galaxies. For the first time, a protocluster of seven galaxies has been confirmed at a distance that astronomers refer to as redshift 7.9, or a mere 650 million years after the big bang. Based on the data collected, astronomers calculated the nascent cluster's future development, finding that it will likely grow in size and mass to resemble the Coma Cluster, a monster of the modern Universe. The precise measurements captured by Webb's Near-Infrared Spectrograph (NIRSpec) were key to confirming the galaxies' collective distance and the high velocities at which they are moving within a halo of dark matter -- more than two million miles per hour (about one thousand kilometers per second). The spectral data allowed astronomers to model and map the future development of the gathering group, all the way to our time in the modern Universe. The prediction that the protocluster will eventually resemble the Coma Cluster means that it could eventually be among the densest known galaxy collections, with thousands of members. Galaxy clusters are the greatest concentrations of mass in the known Universe, which can dramatically warp the fabric of spacetime itself. This warping, called gravitational lensing, can have a magnifying effect for objects beyond the cluster, allowing astronomers to look through the cluster like a giant magnifying glass. The research team was able to utilize this effect, looking through Pandora's Cluster to view the protocluster; even Webb's powerful instruments need an assist from nature to see so far.

Exploring how large clusters like Pandora and Coma first came together has been difficult, due to the expansion of the Universe stretching light beyond visible wavelengths into the infrared, where astronomers lacked high-resolution data before Webb. Webb's infrared instruments were developed specifically to fill in these gaps at the beginning of the Universe's story. The seven galaxies confirmed by Webb were first established as candidates for observation using data from the Hubble Space Telescope's Frontier Fields program. The program dedicated Hubble time to observations using gravitational lensing, to observe very distant galaxies in detail. However, because Hubble cannot detect light beyond near-infrared, there is only so much detail it can see. Webb picked up the investigation, focusing on the galaxies scouted by Hubble and gathering detailed spectroscopic data in addition to imagery. The research team anticipates that future collaboration between Webb and NASA's Nancy Grace Roman Space Telescope, a high-resolution, wide-field survey mission, will yield even more results on early galaxy clusters. With 200 times Hubble's infrared field of view in a Roman will be able to identify more protocluster galaxy candidates, which Webb can follow up to confirm with its spectroscopic instruments. The Roman mission is currently targeted for launch by May 2027.