Jupiter and Saturn images from VLT/MUSE observations in March 2020. They show Jupiter's clouds as well as those in Saturn's atmosphere. Courtesy Irwin, et al. 2026, JGR Planets.
Jupiter’s clouds aren’t what we thought they were. Planetary atmosphere experts have studied them for many years, uncovering new and puzzling mysteries. Recently, several researchers banded together to solve a long-standing mystery about those clouds. It turns out they aren’t made of ammonia ice, which is what everyone has thought for years. Instead, they seem to be largely a mix of smog and ammonium hydrosulfide. That compound forms in the atmosphere as hydrogen sulfide gas passes through ammonia.
A few hundred million years after its formation, the Moon was subject to intense volcanic activity. The distance between the Earth and the Moon was much smaller back then than it is today. Lunar surface rocks reflect a younger age due to a "melting" event at the time. MPS / Alexey Chizhik, CC BY-NC-ND
How old is the Moon? Astronaut-gathered samples from the lunar surface put its age at about 4.35 billion years. However, other evidence suggests it’s much older, around 4.53 billion years old. A team of scientists published a recent paper that suggests the Moon’s surface age was “reset” in a melting event.
The earliest Mars explorers will live in their landers or other Earth-provided habitats while they use local resources to build more permanent colonies and settlements. Credit: NASA
Imagine you’ve just gotten to Mars as part of the first contingent of settlers. Your first challenge: build a long-term habitat using local materials. Those might include water from the polar caps mixed with specific surface soils. They might even require some very personal contributions—your blood, sweat, and tears. Using such in situ materials is the challenge a team of Iranian engineers studied in a research project looking at local materials on Mars.
Artist's rendering of the Starship HLS on the Moon's surface. NASA has contracted with SpaceX to provide the lunar landing system. Credit: SpaceX
The Artemis moon landings are delayed again due to technical difficulties. This time, the problem is with the Orion spacecraft heat shield. NASA administrator Bill Nelson announced that the new landing dates are in April of 2026 for Artemis II and sometime in 2027 for the first human landing during the Artemis III mission.
Radio image of Sagittarius A* black hole in the center of the Milky Way galaxy, obtained from re-analysis by new research. The structure is elongated from east to west. The east side is bright and the west side is dark, which the research team interprets to mean that the east side is moving towards us.
Credit: Miyoshi et al.
Remember that amazing “first image” of Sagittarius A* (Sgr A) black hole at the heart of the Milky Way? Well, it may not be completely accurate, according to researchers at the National Astronomical Observatory of Japan (NAOJ). Instead, the accretion disk around Sgr A* may be more elongated, rather than the circular shape we first saw in 2022.
Astronomers have detected thousands of planets, including dozens that are potentially habitable. To winnow them down, they need to understand their atmospheres and other factors. (NASA Illustration)
Everybody knows that for life to thrive on any world, you need water, warmth, and something to eat. It’s like a habitability mantra. But, what other factors affect habitability? What if you relaxed the conditions conducive to life? Would it still exist? If so, what would it be?
This image shows the galaxy REBELS-25 as seen by the Atacama Large Millimeter/submillimeter Array (ALMA), overlaid on an infrared image of other stars and galaxies. Courtesy ESO.
The early Universe continues to offer surprises and the latest observations of infant galaxies are no exception. Astronomers found a surprisingly Milky Way-like galaxy that existed more than 13 billion years ago. That was a time when the Universe was really just an infant and galaxies should still be early in their formation. A well-formed one in such early history is a bit of a surprise.
The newly discovered galaxy is called REBELS-25. It was found as part of the “Reionization Era Bright Emission Line Survey (REBELS) survey using the Atacama Large Millimeter Array (ALMA) in Chile. The idea of the survey is to search out and measure early galaxies.
REBELS-24 is a massive disc-like galaxy with structures that look like spiral arms. That’s pretty similar to our Milky Way Galaxy. It’s more than 13 billion years old and took billions of years to evolve into its present shape. Like REBELS-25, the Milky Way began as a clumpy, disorganized proto-galaxy not long after the Universe began. It merged with other protogalaxies and evolved into a beautiful spiral shape. It appears to be actively forming stars and is incredibly massive for such a young galaxy.
Early Spirals Aren’t New
So, REBELS-25 raises a big question: why is it so massive and well-evolved at a time when the infant Milky Way was still a clump? That’s what astronomers are working to figure out. “According to our understanding of galaxy formation, we expect most early galaxies to be small and messy looking,” said Jacqueline Hodge, an astronomer at Leiden University, the Netherlands. The fact that REBELS-25 looks so “modern” after less than a billion years does—in a sense—rebel against the generally accepted theories about galaxy formation and evolution.
This isn’t the first time that astronomical observations uncovered early spirals. JWST observations suggest that perhaps a third of early galaxies are already spirals in the infant Universe. Its Cosmic Evolution Early Release Science Survey (CEERS) found many of these in the first 700 million years of cosmic history. So, finding this one looking almost “modern” some 13 billion years ago just adds to the mystery of their formation.
REBELS-25 showed up in ALMA observations, which also gave hints that it had a rotating disk. A set of follow-up observations confirmed the rotation of this galaxy and its spiral arm structures. In addition, the ALMA data found hints of a central bar (just like our Milky Way galaxy has). “ALMA is the only telescope in existence with the sensitivity and resolution to achieve this,” said Renske Smit, a researcher at Liverpool John Moores University in the UK and part of the team that worked on this discovery.
The ALMA data produced an image of REBELS-25 (left) and a map of gas motions in this galaxy which lies more than 13 billion light-years away. Blue coloring indicates movement towards Earth. Red indicates movement away from Earth, with a darker shade representing faster movement. In this case, the red-blue divide of the image shows clearly that the object is rotating, making REBELS-25 the most distant and early (13 billion years old) rotating disc galaxy ever discovered. Courtesy ESO.
Surprisingly, the ALMA data also hinted at more developed features similar to those of the Milky Way. It looks like there’s a central elongated bar, and even spiral arms in REBELS0-25. “Seeing a galaxy with such similarities to our own Milky Way, that is strongly rotation-dominated, challenges our understanding of how quickly galaxies in the early Universe evolve into the orderly galaxies of today’s cosmos,” said Lucie Rowland, a doctoral student at Leiden University who led the research into REBELS-25. “Finding further evidence of more evolved structures would be an exciting discovery, as it would be the most distant galaxy with such structures observed to date.”
What Does This Mean for Galaxy Evolution?
As astronomers discover more of these well-evolved galaxies in the early Universe, they’ll have to adjust the working model of galactic birth and evolution. In that model, the baby galaxies are clumps of stars and gas that come together in collisions and cannibalism to form larger galaxies. It’s typically considered a messy and turbulent time in cosmic history. Infant galaxies collided and grew. They combined their stars and gases to make larger structures. Over time they begin to rotate, which also influences the formation of structures inside the galaxy. Further collisions add more mass to the galaxy, and they also spur bursts of star formation. All of this takes billions of years to accomplish. Or so astronomers always thought.
REBELS-25 and other early spirals challenge that general model. For one thing, REBELS-25 looks like a galaxy that’s evolving at an accelerated pace. Compared to the Milky Way’s ponderous billions of years of evolution, REBELS-25 is going at warp speed. That implies something is pushing that acceleration. T he big thing now will be to explain its advanced evolution at a very young age.
The REBELS program should help astronomers understand more about the processes at work only a few hundred million years after the Big Bang. That survey will supply large enough amounts of data about high-mass galaxies in the early Universe. Those samples should allow astronomers to do targeted studies of more galaxies using both ALMA and JWST. Both observatories are powerful enough to give detailed looks at individual galaxies in those very early epochs of cosmic history.
Low-lying Pacific Ocean nations such as Kiribati are preparing for a future where sea level rise could swamp their coastlines. Credit: NASA Earth Observatory.
The small island nations of the South Pacific are facing the harsh reality of sea level rise. Within 50 years they will be swamped by rising seas linked to climate change. That’s part of a stark forecast from a sea level change science team at NASA and leading universities.
Here's Westerlund 1 in all its glory. This dense cluster of bright stars (with diffraction spikes from JWST's optics). They have a variety of sizes depending on their brightness and distance from us in the cluster, and different colors reflecting different types of star. Patches of billowing red gas can be seen in and around the cluster, lit up by the stars. Small stars in the cluster blend into a background of distant stars and galaxies on black. Courtesy ESA/Webb NASA & CSA, M. Zamani (ESA/Webb), M. G. Guarcello (INAF-OAPA) and the EWOCS team.
A long time ago, the Milky Way Galaxy was busy being a prodigious star-formation engine. In those times, it turned out dozens or hundreds of stars per year. These days, it’s rather more quiescent, cranking out only a few per year. Astronomers want to understand the Milky Way’s star-birth history, so they focus on some of the more recent star litters to study. One of them is Westerlund 1, a young so-called “super star cluster” that looks compact and contains a diverse array of older stars. It was part of a burst of star creation around 4 to 5 million years ago.
A data visualization of the motions of galaxies in structures called basins of attraction. The Milky Way is the red dot. Courtesy of the University of Hawai'i.
If you want to pinpoint your place in the Universe, start with your cosmic address. You live on Earth->Solar System->Milky Way Galaxy->Local Cluster->Virgo Cluster->Virgo Supercluster->Laniakea. Thanks to new deep sky surveys, astronomers now think all those places are part of an even bigger cosmic structure in the “neighborhood” called The Shapley Concentration.
