Eliana Willis

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A passing star could fling Earth out of orbit

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Bad news, earthlings. Computer simulations of the solar system’s future reveal a new risk facing us all: The gravitational tug of a passing star could either cause another planet to smack into Earth or else fling our planet into the sun or far away from it, where any inhabitants would freeze.

Blame Mercury. Astronomers have long known that the innermost planet’s orbit, which is fairly oval-shaped, can become even more elliptical due to gravitational jiggles from Jupiter. Passing stars exacerbate this danger, Nathan Kaib, an astronomer at the Planetary Science Institute who is based in Iowa, and Sean Raymond, an astronomer at the University of Bordeaux in France, report in work submitted to arXiv.org May 7. More

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  • 113 Shares24 Views

    in Space & Astronomy

    A passing star could fling Earth out of orbit

    Bad news, earthlings. Computer simulations of the solar system’s future reveal a new risk facing us all: The gravitational tug of a passing star could either cause another planet to smack into Earth or else fling our planet into the sun or far away from it, where any inhabitants would freeze.

    Blame Mercury. Astronomers have long known that the innermost planet’s orbit, which is fairly oval-shaped, can become even more elliptical due to gravitational jiggles from Jupiter. Passing stars exacerbate this danger, Nathan Kaib, an astronomer at the Planetary Science Institute who is based in Iowa, and Sean Raymond, an astronomer at the University of Bordeaux in France, report in work submitted to arXiv.org May 7. More

  • 125 Shares109 Views

    in Space & Astronomy

    Perseverance takes the first picture of a visible Martian aurora

    On some Martian nights, a subtle, green glow hangs low in the sky, wreathing the horizon in every direction.

    A visible Martian aurora has finally been observed for the first time, researchers report May 14 in Science Advances. The observation, made March 18, 2024, by the Perseverance rover, is also the first of an aurora from the surface of a planet that isn’t Earth. Moreover, it suggests future astronauts may witness ethereal Martian auroras with their own eyes. “It would be a dull or dim green glow to astronauts’ eyes,” says Roger Wiens, a planetary scientist at Purdue University in Lafayette, Ind.

    Auroras can appear when charged particles from space interact with a planet’s atmosphere. They’ve already been spotted on Mercury, Jupiter and every other non-Earth planet in our solar system, but only from orbit. And in Mars’ sky, scientists had only been able to detect auroral wavelengths of light invisible to the naked eye, using instruments. So it wasn’t clear how Martian auroras would appear to future, landed astronauts.

    On March 18, 2024, instruments aboard the Perseverance rover captured an image of a Martian aurora. Though relatively faint, the aurora’s green hues (left) can be made out by comparing the image with one of the typical inky Martian night (right). Due to the phenomenon’s subtle nature, the rover’s instruments were pointed at a low angle over the horizon to peer through a thick layer of the atmosphere. E.W. Knutsen et al/Science Advances 2025

    Compared to many Earthly aurora photos, the new image from Mars is fuzzy. There are a couple reasons for that. First, Perseverance’s cameras perform less well at night, Wiens says. “The instruments aren’t tremendously more sensitive than human eyes,” he says.

    And second, Mars doesn’t have a global magnetic field that concentrates auroras near its poles like Earth does. Instead, its crust is magnetized in patches. That means auroras can appear all over the planet, but they’re relatively dim. More

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    Check out some of the weird rocks that have turned up on Mars

    As the Mars rover Perseverance crested the top of Witch Hazel Hill, its operators back on Earth expected amazing things. This area on the western rim of the Jezero crater, along an ancient river delta that Perseverance has been exploring since it landed in 2021, is thought to contain some of the oldest rocks on the planet’s surface. The light-toned, layered materials promise a record of a wetter time, possibly one that hosted life.

    The team did not expect what they found on March 11: a dark rock resembling a clutch of frog’s eggs. Dubbed St. Paul’s Bay, the rock looks nothing like its neighbors. Where it came from and how it formed are a mystery. More

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    A new iron compound hints ‘primordial’ helium hides in Earth’s core

    Scientists have coaxed one of the universe’s most stubborn elements into a new compound.

    Formed under intense pressures, the newly discovered compound packs helium atoms into crystalline iron, researchers report February 25 in Physical Review Letters. The compound joins a short list of materials that incorporate the normally unreactive element and suggests that helium from the early solar system could be stored in the iron that makes up Earth’s core.

    Helium is one of the least reactive elements on the periodic table. Like the other noble gases, helium doesn’t gain or lose electrons easily and so does not normally form chemical compounds. But under extremely high pressures, helium can interact with a few other elements, including nitrogen and sodium — and now iron, research shows.

    An iron-helium compound, shown here in artificial color using a technique called secondary ion mass spectrometry, forms under high temperature and pressure. Blue and black areas mark the background, while the orange and red area represents the sample. ©2025 Hirose et al. CC-BY-ND

    To make the new iron compound, physicist Kei Hirose of the University of Tokyo and his colleagues squeezed iron and helium together in a diamond anvil cell, a high-pressure device that subjected the elements to pressures greater than 50,000 Earth atmospheres and temperatures above 1,000 degrees Celsius. This compression formed crystals containing both iron and helium.

    The volume of the crystal formed was larger than that of a crystal of pure iron at the same pressure, the team found. The researchers attributed this increase to helium ions packing into interstitial sites, the tiny spaces between iron atoms in the crystal. But the helium atoms don’t bond directly to iron — they’re too unreactive, even at extreme conditions. More

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    in Space & Astronomy

    Uranus emits more heat than previously thought

    Uranus emits more energy than it gets from the sun, two new studies report — a discovery that contradicts findings from the venerable Voyager spacecraft.

    When Voyager 2 sped past Uranus on January 24, 1986, the spacecraft detected no significant excess heat from the planet, making it seemingly unique among the sun’s giant worlds. However, new observations from space- and ground-based telescopes reveal that Uranus does in fact radiate more energy than sunlight provides, two research teams report in work submitted to arXiv.org in late February. More

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    Juno reveals dozens of lava lakes on Jupiter’s moon Io

    Jupiter’s moon Io, the most volcanically active body in the solar system, is littered with hundreds of erupting volcanoes. High-resolution images now reveal several dozen lava lakes, researchers report in the February Journal of Geophysical Research: Planets. These lakes are far larger than their analogs on Earth, and their structure sheds light on how magma moves beneath the surface of Io. 

    Io’s volcanism — probably present over the moon’s entire 4.6-billion-year existence — was discovered when the Voyager spacecraft flew by in 1979. The volcanic activity is caused by the intense gravitational pulls of Jupiter and nearby moons, which deform Io by tens of meters. “This squeezing is heating the body,” says Alessandro Mura, a planetary scientist at Italy’s National Institute for Astrophysics in Rome. More

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    A private mission to Venus aims to look for signs of life

    BOSTON —Droplets of Venus’ clouds may someday come to Earth. Researchers are testing a device that can gather mist from our planetary neighbor’s atmosphere and deliver it to scientists so they can test the samples for signs of life.

    Venus is not an obvious place to look for life. Its globe-spanning cloud decks are made of sulfuric acid, “a feature that was long believed to be sterile for any organic chemistry,” said MIT planetary scientist Iaroslav Iakubivskyi in a Feb. 15 talk at a meeting of the American Association for the Advancement of Science.

    But in the last few years, lab experiments by Iakubivskyi and colleagues have suggested that sulfuric acid can support the organic chemistry that gives rise to stable nucleic and amino acids — the building blocks of DNA and proteins. Together, the data suggest that “rather than being a disruptive force, sulfuric acid might actually serve as a potential solvent for life-essential molecules,” he said. “Still, we have to go to Venus to test it.”

    A future mission to Venus could include floating a cloud-catching device from a giant balloon in the planet’s sulfuric acid atmosphere, as shown in this illustration.W. Buchanan

    Iakubivskyi’s team is working with the private spaceflight company Rocket Lab on a series of Venus probes called the Morning Star Missions. The first, a probe that will fall through Venus’ atmosphere and measure the sizes of sulfuric acid droplets, is slated to launch in 2026. A later mission would use a two-ton rocket to launch samples into Venus’ orbit to be picked up by a spacecraft returning to Earth. If successful, Morning Star would be the first private mission to another planet.

    Inspired by fog-catching plants in the Atacama desert, the team built a prototype cloud catcher from four layers of wire mesh. The wires can be charged to ionize atmospheric droplets and attract them to the mesh. More

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    A weird ice that may form on alien planets has finally been observed

    A strange type of ice thought to dwell deep in the oceans of alien planets has finally been proven to exist.

    For the first time, researchers have directly observed a sort of hybrid phase of water called plastic ice, which forms at high temperatures and pressures and exhibits traits of both solid ice and liquid water. The observations, reported February 12 in Nature, may help researchers better understand the internal architecture and processes of other worlds in our solar system and beyond, some of which might be habitable. More