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By NASA
6 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
This artist’s concept shows a brown dwarf — an object larger than a planet but not massive enough to kickstart fusion in its core like a star. Brown dwarfs are hot when they form and may glow like this one, but over time they get closer in temperature to gas giant planets like Jupiter. NOIRLab/NSF/AURA/R. Proctor An unusual cosmic object is helping scientists better understand the chemistry hidden deep in Jupiter and Saturn’s atmospheres — and potentially those of exoplanets.
Why has silicon, one of the most common elements in the universe, gone largely undetected in the atmospheres of Jupiter, Saturn, and gas planets like them orbiting other stars? A new study using observations from NASA’s James Webb Space Telescope sheds light on this question by focusing on a peculiar object that astronomers discovered by chance in 2020 and called “The Accident.”
The results were published on Sept. 4 in the journal Nature.
As shown in this graphic, brown dwarfs can be far more massive than even large gas planets like Jupiter and Saturn. However, they tend to lack the mass that kickstarts nuclear fusion in the cores of stars, causing them to shine. NASA/JPL-Caltech The Accident is a brown dwarf, a ball of gas that’s not quite a planet and not quite a star. Even among its already hard-to-classify peers, The Accident has a perplexing mix of physical features, some of which have been previously seen in only young brown dwarfs and others seen only in ancient ones. Because of those features, it slipped past typical detection methods before being discovered five years ago by a citizen scientist participating in Backyard Worlds: Planet 9. The program lets people around the globe look for new discoveries in data from NASA’s now-retired NEOWISE (Near-Earth Object Wide-field Infrared Survey Explorer), which was managed by NASA’s Jet Propulsion Laboratory in Southern California.
The brown dwarf nicknamed “The Accident” can be seen moving in the bottom left corner of this video, which shows data from NASA’s now-retired NEOWISE (Near-Earth Object Wide-Field Infrared Survey Explorer), launched in 2009 with the moniker WISE. NASA/JPL-Caltech/Dan Caselden The Accident is so faint and odd that researchers needed NASA’s most powerful space observatory, Webb, to study its atmosphere. Among several surprises, they found evidence of a molecule they couldn’t initially identify. It turned out to be a simple silicon molecule called silane (SiH4). Researchers have long expected — but been unable — to find silane not only in our solar system’s gas giants, but also in the thousands of atmospheres belonging to brown dwarfs and to the gas giants orbiting other stars. The Accident is the first such object where this molecule has been identified.
Scientists are fairly confident that silicon exists in Jupiter and Saturn’s atmospheres but that it is hidden. Bound to oxygen, silicon forms oxides such as quartz that can seed clouds on hot gas giants, bearing a resemblance to dust storms on Earth. On cooler gas giants like Jupiter and Saturn, these types of clouds would sink far beneath lighter layers of water vapor and ammonia clouds, until any silicon-containing molecules are deep in the atmosphere, invisible even to the spacecraft that have studied those two planets up close.
Some researchers have also posited that lighter molecules of silicon, like silane, should be found higher up in these atmospheric layers, left behind like traces of flour on a baker’s table. That such molecules haven’t appeared anywhere except in a single, peculiar brown dwarf suggests something about the chemistry occurring in these environments.
“Sometimes it’s the extreme objects that help us understand what’s happening in the average ones,” said Faherty, a researcher at the American Museum of Natural History in New York City, and lead author on the new study.
Happy accident
Located about 50 light-years from Earth, The Accident likely formed 10 billion to 12 billion years ago, making it one of the oldest brown dwarfs ever discovered. The universe is about 14 billion years old, and at the time that The Accident developed, the cosmos contained mostly hydrogen and helium, with trace amounts of other elements, including silicon. Over eons, elements like carbon, nitrogen, and oxygen forged in the cores of stars, so planets and stars that formed more recently possess more of those elements.
Webb’s observations of The Accident confirm that silane can form in brown dwarf and planetary atmospheres. The fact that silane seems to be missing in other brown dwarfs and gas giant planets suggests that when oxygen is available, it bonds with silicon at such a high rate and so easily, virtually no silicon is left over to bond with hydrogen and form silane.
So why is silane in The Accident? The study authors surmise it is because far less oxygen was present in the universe when the ancient brown dwarf formed, resulting in less oxygen in its atmosphere to gobble up all the silicon. The available silicon would have bonded with hydrogen instead, resulting in silane.
“We weren’t looking to solve a mystery about Jupiter and Saturn with these observations,” said JPL’s Peter Eisenhardt, project scientist for the WISE (Wide-field Infrared Survey Explorer) mission, which was later repurposed as NEOWISE. “A brown dwarf is a ball of gas like a star, but without an internal fusion reactor, it gets cooler and cooler, with an atmosphere like that of gas giant planets. We wanted to see why this brown dwarf is so odd, but we weren’t expecting silane. The universe continues to surprise us.”
Brown dwarfs are often easier to study than gas giant exoplanets because the light from a faraway planet is typically drowned out by the star it orbits, while brown dwarfs generally fly solo. And the lessons learned from these objects extend to all kinds of planets, including ones outside our solar system that might feature potential signs of habitability.
“To be clear, we’re not finding life on brown dwarfs,” said Faherty. “But at a high level, by studying all of this variety and complexity in planetary atmospheres, we’re setting up the scientists who are one day going to have to do this kind of chemical analysis for rocky, potentially Earth-like planets. It might not specifically involve silicon, but they’re going to get data that is complicated and confusing and doesn’t fit their models, just like we are. They’ll have to parse all those complexities if they want to answer those big questions.”
More about WISE, Webb
A division of Caltech, JPL managed and operated WISE for NASA’s Science Mission Directorate. The mission was selected competitively under NASA’s Explorers Program managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland. The NEOWISE mission was a project of JPL and the University of Arizona in Tucson, supported by NASA’s Planetary Defense Coordination Office.
For more information about WISE, go to:
https://www.nasa.gov/mission_pages/WISE/main/index.html
The James Webb Space Telescope is the world’s premier space science observatory, and an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
To learn more about Webb, visit:
https://science.nasa.gov/webb
News Media Contacts
Calla Cofield
Jet Propulsion Laboratory, Pasadena, Calif.
626-808-2469
calla.e.cofield@jpl.nasa.gov
Christine Pulliam
Space Telescope Science Institute, Baltimore, Md.
cpulliam@stsci.edi
2025-113
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Last Updated Sep 09, 2025 Related Terms
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By NASA
Patricia White is a contracting officer at NASA’s Stennis Space Center, where she contributes to NASA’s Artemis program that will send astronauts to the Moon to prepare for future human exploration of Mars. NASA/Danny Nowlin When NASA’s Artemis II mission launches in 2026, it will inspire the world through discovery in a new Golden Age of innovation and exploration.
It will be another inspiring NASA moment Patricia White can add to her growing list.
White supports the Artemis program to send astronauts to the Moon to prepare for future human exploration of Mars as a contracting officer at NASA’s Stennis Space Center near Bay St. Louis, Mississippi.
White takes special pride in the test operations contract she helped draft. The contract provides support to the Fred Haise Test Stand, which tests the RS-25 engines that will help power NASA’s SLS (Space Launch System) rocket on Artemis missions.
“I was awestruck the first time I witnessed an engine test,” White said. “I remember how small I felt in comparison to this big and fascinating world, and I wondered what that engine would see that I would never be able to see.”
Four RS-25 engines tested at NASA Stennis will help launch Artemis II with four astronauts to venture around the Moon. As the first crewed Artemis mission, it will represent another milestone for the nation’s human space exploration effort.
From Interstate Signs to NASA Career
White describes NASA Stennis as a hidden gem. Growing up in nearby Slidell, Louisiana, she had driven by the interstate signs pointing toward NASA Stennis her entire life.
When she heard about a job opportunity at the center, she immediately applied. Initially hired as a contractor with only a high school diploma in February 2008, White found her motivation among NASA’s ranks.
“I work with very inspiring people, and it only took one person to say, ‘You should go to college’ to give me the courage to go so late in life,” she said.
Hard But Worth It
White began college classes in her 40s and finished at 50. She balanced a marriage, full-time job, academic studies, and household responsibilities. When she started her educational journey, her children were either toddlers or newborns. They were growing up as she stayed in school for nine years while meeting life’s challenges.
“It was hard, but it was so worth it,” she said. “I love my job and what I do, and even though it is crazy busy, I look forward to working at NASA every single day.”
She joined NASA officially in 2013, going from contractor to civil servant.
Setting an Example
White’s proudest work moment came when she brought home the NASA Early Career Achievement award and medal. It served as a tangible symbol of her success she could share with her family.
“It was a long road from being hired as an intern, and we all made extraordinary sacrifices,” she said. “I wanted to share it with them and set a good example for my children.”
As Artemis II prepares to carry humans back to lunar orbit for the first time in over 50 years, White takes pride knowing her work helps power humanity’s return to deep space exploration. Her work is proof that sometimes the most important journeys begin right in one’s own backyard.
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By NASA
Explore This Section Overview Science Science Findings Juno’s Orbits Spacecraft People Stories Multimedia JunoCam Images Jupiter hosts the brightest and most spectacular auroras in the Solar System. Near its poles, these shimmering lights offer a glimpse into how the planet interacts with the solar wind and moons swept by Jupiter’s magnetic field. Unlike Earth’s northern lights, the largest moons of Jupiter create their own auroral signatures in the planet’s atmosphere — a phenomenon that Earth’s Moon does not produce. These moon-induced auroras, known as “satellite footprints,” reveal how each moon interacts with its local space environment.
Juno capturing the marks on Jupiter of all four Galilean moons. The auroras related to each are labeled Io, Eur (for Europa), Gan (for Ganymede), and Cal (for Callisto). NASA/JPL-Caltech/SwRI/UVS team/MSSS/Gill/Jónsson/Perry/Hue/Rabia Before NASA’s Juno mission, three of Jupiter’s four largest moons, known as Galilean moons — Io, Europa, and Ganymede — were shown to produce these distinct auroral signatures. But Callisto, the most distant of the Galilean moons, remained a mystery. Despite multiple attempts using NASA’s Hubble Space Telescope, Callisto’s footprint had proven elusive, both because it is faint and because it most often lies atop the brighter main auroral oval, the region where auroras are displayed.
NASA’s Juno mission, orbiting Jupiter since 2016, offers unprecedented close-up views of these polar light shows. But to image Callisto’s footprint, the main auroral oval needs to move aside while the polar region is being imaged. And to bring to bear Juno’s arsenal of instruments studying fields and particles, the spacecraft’s trajectory must carry it across the magnetic field line linking Callisto and Jupiter.
These two events serendipitously occurred during Juno’s 22nd orbit of the giant planet, in September 2019, revealing Callisto’s auroral footprint and providing a sample of the particle population, electromagnetic waves, and magnetic fields associated with the interaction.
Jupiter’s magnetic field extends far beyond its major moons, carving out a vast region (magnetosphere) enveloped by, and buffeted by, the solar wind streaming from our Sun. Just as solar storms on Earth push the northern lights to more southern latitudes, Jupiter’s auroras are also affected by our Sun’s activity. In September 2019, a massive, high-density solar stream buffeted Jupiter’s magnetosphere, briefly revealing — as the auroral oval moved toward Jupiter’s equator — a faint but distinct signature associated with Callisto. This discovery finally confirms that all four Galilean moons leave their mark on Jupiter’s atmosphere, and that Callisto’s footprints are sustained much like those of its siblings, completing the family portrait of the Galilean moon auroral signatures.
An international team of scientists led by Jonas Rabia of the Institut de Recherche en Astrophysique et Planétologie (IRAP), CNRS, CNES, in Toulouse, France, published their paper on the discovery, “In situ and remote observations of the ultraviolet footprint of the moon Callisto by the Juno spacecraft,” in the journal Nature Communications on Sept. 1, 2025.
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Last Updated Sep 02, 2025 Related Terms
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By NASA
NASA A Titan-Centaur rocket carrying the Viking 1 spacecraft launches from Complex 41 at Cape Canaveral Air Force Station on Aug. 20, 1975. Viking 1 touched down on the red planet on July 20, 1976, becoming the first truly successful landing on Mars. Viking 1 was the first of a pair of complex deep space probes that were designed to reach Mars and to collect evidence on the possibility on life on Mars.
NASA’s exploration of Mars continues, with rovers exploring the planet’s surface and spacecraft studying from orbit. The agency’s Artemis missions will also lay the groundwork for the first crewed missions to Mars.
Learn more about Viking 1 and see the first photo it took upon landing.
Image credit: NASA
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By Space Force
The visit marked Bentivegna’s first official multi-nation tour of the EUCOM AOR since assuming the top enlisted position in the U.S. Space Force.
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