The study of planets and moons
NASA is serving up a double scoop of delicious Saturn imagery in two flavors — near-infrared from the James Webb Space Telescope, and visible light from the Hubble Space Telescope.
The days are getting longer. Not by much though since we're talking about fractions of a millisecond, but the rate at which our planet is slowing down is, according to a new study, completely without precedent in the last 3.6 million years. The culprit isn't the Moon, the Sun or anything in Earth's interior. It's us, homo sapiens.
High in the Chilean Andes, at an altitude where the air is thin and the Sun is intense, a salt flat is hiding something remarkable. Locked inside ancient crystals of gypsum are the preserved remains of microscopic life, fossils of organisms that lived thousands of years ago, sitting alongside communities of microbes that are alive right now. Scientists studying this extraordinary place think it could be the closest thing on Earth to where life might once have existed on Mars.
When we think of asteroids, we almost immediately think of giant rocks bouncing around like the iconic chase scene in Empire Strikes Back, and we often hear how they are remnants from the birth of the solar system. While the asteroids that comprise the Main Asteroid Belt of our solar system are not only spread far apart from each other, they are also not all made of rock. One asteroid approximately the size of the State of Massachusetts called 16 Psyche is made of metal, which planetary scientists hypothesize could be the remnants of a protoplanet’s core that didn’t build into a full-fledged planet. But how did such a unique asteroid form?
What happens in a protoplanetary disk to create planetesimals around a star? We know the general story -- the material begins to clump together and eventually grows from dust grains to rocky bodies capable of sticking together to make planets. But, how does that dust begin the aggregation journey? That's what a research team from the Switzerland wanted to know. So, they did experiments aboard parabolic micro-gravity flights to find an answer.
One particularly well known fact about the Moon is that it doesn’t have much of a magnetosphere to speak of. There’s no blanket to protect it from the solar wind ravaging its surface, blowing away its atmosphere and charging the notoriously dangerous dust particles that make up its regolith. However, scientists have also known for around 60 years that some parts of the moon do experience sudden spikes in a magnetic field - some of which are up to 10 times stronger than the background magnetization. Since their discovery, these “lunar external magnetic enhancements” (LEMEs) have puzzled researchers - what was causing them, and why did they reach so high above the lunar surface that spacecraft could see them? A new paper published in The Astrophysical Journal Letters by Shu-Hua Lai and her colleagues at the National Central University in Taiwan explains for the first time what is likely causing these LEMEs - a novel type of the Kelvin-Helmholtz instability.
Beneath Europa's cracked and frozen shell lies a vast ocean of liquid water and what's seeping up through that ice may be one of the most compelling clues we have ever found about the moon's potential for life. A new analysis of James Webb Space Telescope observations has revealed that carbon dioxide on Europa's surface is far more widespread than previously thought, spreading across multiple regions of geological terrain in a distinctive lens like pattern. The findings are rewriting what we thought we knew about how material moves between Europa's hidden ocean and its surface.
Every planet with a magnetic field has a radiation belt, a region of space where charged particles get trapped and flung around at extraordinary speeds. Earth has two of them, and they've been puzzling scientists for decades. Now, a physicist at the University of Helsinki has built a model that defines a universal upper limit to just how energetic those belts can ever get. The answer applies not just to Earth, but to every planet in the Solar System, every gas giant, and even the strange objects sitting halfway between planets and stars.
So that's all nice. But why now? That's the question everyone asks. We went decades — centuries, millennia really — without seeing a single rock that didn't have a "Made in the Solar System" sticker on it. Then, in the span of less than ten years, we get the Big Three: 'Oumuamua, Borisov, and now 3I/ATLAS.
So why should we expect interstellar comets like 3I/ATLAS and 'Oumuamua and even to some extent Borisov to be different-different?
A NASA spacecraft that spent seven years mapping Earth's invisible radiation shields has made its final journey home and it came back years ahead of schedule. Van Allen Probe A, launched in 2012 to study the powerful belts of charged particles that wrap around our planet, re-entered Earth's atmosphere in March 2026, most of it burning up in a blaze of friction and heat. What brought it down early wasn't a malfunction or a mission decision. It was the Sun and that twist in the story tells us something important.
Multiple mobile phones, dashcams, and dedicated meteor cameras capture a fireball over part of Europe on Sunday night. Thousands of people witnessed it, and the ESA's Planetary Defence Team is analyzing it. So far, it looks like it was a few meters in diameter. It lit up the sky, and some debris even struck some buildings in Koblenz, Germany.
Scientists occasionally have a hard time figuring out whether data they are seeing is an actual physical phenomenon or just a trick of their instrumentation. A new paper in The Planetary Science Journal from Jessica Sunshine and their colleagues at the University of Maryland describes one such confusing scenario. In this case, the researchers noted some fan-like patterns across the surface of Dimorphos, the asteroid hit by NASA’s DART mission, and thought it might be a trick of their camera. But after some image correction, computation, and physical experimentation, they determined the patterns were caused by the first-ever documented cases of material transfer between two asteroids.
Jupiter's powerful, continuous aurorae dwarf those of Earth. Scientists know that Jupiter's Galilean moons created bright spots on Jupiter's northern aurora. The JWST observed these bright spots and generated infrared spectra of them for the first time. Those observations showed that Io's bright spot is extremely variable in both temperature and density, and researchers want to know why.
Asteroids are critical to unlock our understanding of the early solar system. These chunks of rock and dust were around at the very beginning, and they haven’t been as modified by planetary formation processes as, say, Earth has been. So scientists were really excited to get ahold of samples from Ryugu when they were returned by Hayabusa-2 a few years ago. However, when they started analyzing the magnetic properties of those samples, different research groups came up with different answers. Theorizing those conflicting results came from small sample sizes, a new paper recently published in JGR Planets from Masahiko Sato and their colleagues at the University of Tokyo used many more samples to finally dig into the magnetic history of these first ever returned asteroid samples.
Craters, craters, and yet more craters: this snapshot from ESA’s Mars Express is packed full of them, each as fascinating as the last.
The rocks that twelve astronauts carried home from the Moon fifty years ago have just rewritten our understanding of lunar history. A new analysis of Apollo samples has finally resolved one of the most stubborn debates in planetary science and the answer turns out to be one that neither side of the argument was entirely right about.
A visitor from another star system has just had its portrait taken by a spacecraft on its way to Jupiter and the image is superb. Comet 3I/ATLAS, only the third interstellar object ever discovered passing through our Solar System, has been captured in stunning detail by ESA's JUICE mission, revealing a glowing halo of gas, a sweeping tail, and hints of jets erupting from its ancient, icy heart. But the picture itself is just the beginning of the story.
Jupiter is the largest planet in the solar system and has proudly boasted about this since time immemorial, with its scientific confirmation occurring by Galileo Galilei in 1610. It was later found that Jupiter has a bulging equator caused by its rapid rotation, turbulent atmosphere, and complex interior mechanisms despite its massive size, and scientists have even measured its “waistline” down to a tenth of a kilometer. Now, imagine being the largest planet in the solar system and you’re told you’re not as big as you thought. Where probably most humans would be thrilled to find this out, how do you respond if you’re Jupiter?
Researchers in Brazil have discovered another tektite field. Tektites are gravel-sized chunks of natural glass formed by impacts and spread over a wide area. Their presence indicates that a powerful impact occurred 6 million years ago.
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