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Zircon Crystals Could Reveal Earth’s Path Among the Stars

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By Tom Metcalfe , Eos/AGU.  Excerpt: Tiny crystals in Earth’s crust may have recorded meteorite and comet impacts as our planet traveled through the spiral arms of the Milky Way over more than 4 billion years, according to new research. ...The key to the latest research was in the ratios of isotopes—forms of the same chemical element that have different numbers of neutrons—in the oxygen atoms of zircon’s silicate group. The relative levels of oxygen isotopes in samples of zircon crystals can tell geologists whether the crystals formed high in the crust, perhaps while interacting with water and sediments, or deeper within Earth’s mantle. ...The scientists evaluated the data’s “ kurtosis ,” or the measure of how flat or peaked a distribution is. ...The researchers determined that periods of high oxygen isotope kurtosis corresponded to times when our solar system was crossing the dense spiral arms of the Milky Way galaxy. Such crossings occurred roughly every 187 million years on aver...
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Scientists May Have Finally Detected a Solid Inner Core on Mars

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By Javier Barbuzano , Eos/AGU.  Excerpt: Almost a decade after NASA’s InSight mission put the first working seismometer on the Martian surface, ...scientists reported seismic evidence that Mars has a solid inner core, an unexpected finding that challenges earlier studies that suggested the planet’s core was entirely molten. ...the interior of Mars has layers... [with] different densities and can be solid or liquid. As seismic waves move through the layers, they are bent or reflected, especially at boundaries where density changes sharply. ...Previous analyses of InSight data had already mapped the structure of the Martian  crust  and  mantle  and also revealed that the planet has a surprisingly  large molten metallic core , spanning nearly half its radius. ...the new finding caught InSight scientists off guard....  Full article at https://eos.org/articles/scientists-may-have-finally-detected-a-solid-inner-core-on-mars .  See also Dust devil migrat...
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Exoplanet without a sun found gobbling up 6 billion tons of gas and dust per second

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By Victoria Corless , Space.com.  Excerpt: Scientists have identified a lone planet with a ferocious appetite. Located in the Chamaeleon constellation roughly 620 light-years away, the rogue planet, named Cha 1107-7626, exists in the vast emptiness of space, far from the warmth of any star. ...Using the  European Southern Observatory 's (ESO)  Very Large Telescope  (VLT), astronomers have caught it pulling in gas and dust at an astonishing rate: six billion tons every single second. Never before has a rogue planet, or any planet, been observed growing this fast. "This is the strongest accretion episode ever recorded for a planetary-mass object," Almendros-Abad said. With a mass equivalent to between five and 10 Jupiters, Cha 1107-7626 is one of the lowest-mass free-floating planets known to host a disk and show active accretion. Observations from ESO's VLT and NASA's  James Webb Space Telescope  (JWST) reveal telltale signs of a rich, evolving system ...sil...
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Winding up for planet formation

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By ScienceAdviser.  Excerpt: Understanding how planets form in the disks of dust and gas around newborn planets is a work in progress. Only recently have astronomers  spied planets carving out rings in the disks  by scooping up material. But some disks have a spiral structure. Is that the result of gravitational interactions in the disk itself, before planets form, or are newborn planets themselves warping the disk into a spiral? A team of astronomers say they’ve resolved this chicken-and-egg puzzle using the Atacama Large Millimeter/submillimeter Array (ALMA), a collection of 66 dish antennas high up in the Chilean Andes which can see dust in disks but not the planets themselves. If the spiral arms formed in the disk spontaneously, over time they would wind tighter, like the spring in a wind-up clock. Arms formed by planets would keep their shape as they move around the nascent star. The team used archival and new images taken over 7 years of the young star IM Lup to mak...
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Best Evidence Yet for Past Life on Mars?

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By David L. Chandler , Sky & Telescope.  Excerpt: The Perseverance has found compounds associated with life on Earth. But whether they indicate life on Mars awaits sample return. ...One rock,...is dotted with colored spots, ...The leopard spots, it turns out, appear to be  reaction fronts  — areas of contact between an expanding chemical reaction and surrounding rock. The material in the rings is composed of two different iron-rich minerals: vivianite (iron phosphate) and greigite (iron sulfide). Both of these minerals, on Earth, are usually associated with decaying plant matter or are products of microbial activity. ...The team cautions, however, that a non-biological formation process has not been ruled out.  Full article at https://skyandtelescope.org/astronomy-news/best-evidence-yet-for-past-life-on-mars/ .  See also New York Times article .
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How an Interstellar Interloper Spurred Astronomers into Action

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By Kimberly M. S. Cartier , Eos/AGU.  Excerpt: On 1 July 2025, astronomers detected a visitor from the deep reaches of space. At the time of discovery, the object was just inside Jupiter’s orbit and was zipping across our solar system 4 times faster than the New Horizons probe sped past Pluto. It was first spotted by the Asteroid Terrestrial-impact Last Alert System ( ATLAS ) in Chile, which was specifically designed to spot small, fast-moving objects like this. ATLAS sent out a public,  automated alert , and when astronomers saw it, they quickly went to work calculating the object’s orbit and trajectory....  Full article at https://eos.org/features/how-an-interstellar-interloper-spurred-astronomers-into-action .
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The Vera Rubin Observatory is ready to revolutionize astronomy

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By Lisa Grossman , Science News.  Excerpt: Perched on a high, flat-topped mountain called Cerro Pachón, the Rubin Observatory ...can investigate some of the universe’s slowest, most eternal processes, such as the assembly of galaxies and the expansion of the cosmos. And by mapping the entire southern sky every couple of nights, it can track some of the universe’s fastest and most ephemeral events, including exploding stars and  visits from interstellar comets . ...Rubin data will be made available online to anyone in the world, from professional astronomers to elementary school students. ...the observatory has what’s now the  largest digital camera ever built ...at 1.65 meters wide...It combines 189 individual CCDs...roughly the same number of pixels as 260 smartphone cameras. ...In June, the telescope hit another big milestone:  releasing Rubin’s first images  to the public. ...the Rubin team shared videos made up of hundreds of individual images from...
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