Members Can Post Anonymously On This Site
-
Similar Topics
-
By NASA
5 min read
Percolating Clues: NASA Models New Way to Build Planetary Cores
NASA’s Perseverance rover was traveling in the channel of an ancient river, Neretva Vallis, when it captured this view of an area of scientific interest nicknamed “Bright Angel” – the light-toned area in the distance at right. The area features light-toned rocky outcrops that may represent either ancient sediment that later filled the channel or possibly much older rock that was subsequently exposed by river erosion. NASA/JPL-Caltech A new NASA study reveals a surprising way planetary cores may have formed—one that could reshape how scientists understand the early evolution of rocky planets like Mars.
Conducted by a team of early-career scientists and long-time researchers across the Astromaterials Research and Exploration Science (ARES) Division at NASA’s Johnson Space Center in Houston, the study offers the first direct experimental and geochemical evidence that molten sulfide, rather than metal, could percolate through solid rock and form a core—even before a planet’s silicate mantle begins to melt.
For decades, scientists believed that forming a core required large-scale melting of a planetary body, followed by heavy metallic elements sinking to the center. This study introduces a new scenario—especially relevant for planets forming farther from the Sun, where sulfur and oxygen are more abundant than iron. In these volatile-rich environments, sulfur behaves like road salt on an icy street—it lowers the melting point by reacting with metallic iron to form iron-sulfide so that it may migrate and combine into a core. Until now, scientists didn’t know if sulfide could travel through solid rock under realistic planet formation conditions.
Working on this project pushed us to be creative. It was exciting to see both data streams converge on the same story.
Dr. Jake Setera
ARES Scientist with Amentum
The study results gave researchers a way to directly observe this process using high-resolution 3D imagery—confirming long-standing models about how core formation can occur through percolation, in which dense liquid sulfide travels through microscopic cracks in solid rock.
“We could actually see in full 3D renderings how the sulfide melts were moving through the experimental sample, percolating in cracks between other minerals,” said Dr. Sam Crossley of the University of Arizona in Tucson, who led the project while a postdoctoral fellow with NASA Johnson’s ARES Division. “It confirmed our hypothesis—that in a planetary setting, these dense melts would migrate to the center of a body and form a core, even before the surrounding rock began to melt.”
Recreating planetary formation conditions in the lab required not only experimental precision but also close collaboration among early-career scientists across ARES to develop new ways of observing and analyzing the results. The high-temperature experiments were first conducted in the experimental petrology lab, after which the resulting samples—or “run products”—were brought to NASA Johnson’s X-ray computed tomography (XCT) lab for imaging.
A molten sulfide network (colored gold) percolates between silicate mineral grains in this cut-out of an XCT rendering—rendered are unmelted silicates in gray and sulfides in white. Credit: Crossley et al. 2025, Nature Communications X-ray scientist and study co-author Dr. Scott Eckley of Amentum at NASA Johnson used XCT to produce high-resolution 3D renderings—revealing melt pockets and flow pathways within the samples in microscopic detail. These visualizations offered insight into the physical behavior of materials during early core formation without destroying the sample.
The 3D XCT visualizations initially confirmed that sulfide melts could percolate through solid rock under experimental conditions, but that alone could not confirm whether percolative core formation occurred over 4.5 billion years ago. For that, researchers turned to meteorites.
“We took the next step and searched for forensic chemical evidence of sulfide percolation in meteorites,” Crossley said. “By partially melting synthetic sulfides infused with trace platinum-group metals, we were able to reproduce the same unusual chemical patterns found in oxygen-rich meteorites—providing strong evidence that sulfide percolation occurred under those conditions in the early solar system.”
To understand the distribution of trace elements, study co-author Dr. Jake Setera, also of Amentum, developed a novel laser ablation technique to accurately measure platinum-group metals, which concentrate in sulfides and metals.
“Working on this project pushed us to be creative,” Setera said. “To confirm what the 3D visualizations were showing us, we needed to develop an appropriate laser ablation method that could trace the platinum group-elements in these complex experimental samples. It was exciting to see both data streams converge on the same story.”
When paired with Setera’s geochemical analysis, the data provided powerful, independent lines of evidence that molten sulfide had migrated and coalesced within a solid planetary interior. This dual confirmation marked the first direct demonstration of the process in a laboratory setting.
Dr. Sam Crossley welds shut the glass tube of the experimental assembly. To prevent reaction with the atmosphere and precisely control oxygen and sulfur content, experiments needed to be sealed in a closed system under vacuum. Credit: Amentum/Dr. Brendan Anzures The study offers a new lens through which to interpret planetary geochemistry. Mars in particular shows signs of early core formation—but the timeline has puzzled scientists for years. The new results suggest that Mars’ core may have formed at an earlier stage, thanks to its sulfur-rich composition—potentially without requiring the full-scale melting that Earth experienced. This could help explain longstanding puzzles in Mars’ geochemical timeline and early differentiation.
The results also raise new questions about how scientists date core formation events using radiogenic isotopes, such as hafnium and tungsten. If sulfur and oxygen are more abundant during a planet’s formation, certain elements may behave differently than expected—remaining in the mantle instead of the core and affecting the geochemical “clocks” used to estimate planetary timelines.
This research advances our understanding of how planetary interiors can form under different chemical conditions—offering new possibilities for interpreting the evolution of rocky bodies like Mars. By combining experimental petrology, geochemical analysis, and 3D imaging, the team demonstrated how collaborative, multi-method approaches can uncover processes that were once only theoretical.
Crossley led the research during his time as a McKay Postdoctoral Fellow—a program that recognizes outstanding early-career scientists within five years of earning their doctorate. Jointly offered by NASA’s ARES Division and the Lunar and Planetary Institute in Houston, the fellowship supports innovative research in astromaterials science, including the origin and evolution of planetary bodies across the solar system.
As NASA prepares for future missions to the Moon, Mars, and beyond, understanding how planetary interiors form is more important than ever. Studies like this one help scientists interpret remote data from spacecraft, analyze returned samples, and build better models of how our solar system came to be.
For more information on NASA’s ARES division, visit: https://ares.jsc.nasa.gov/
Victoria Segovia
NASA’s Johnson Space Center
281-483-5111
victoria.segovia@nasa.gov
Share
Details
Last Updated May 22, 2025 Related Terms
Astromaterials Planetary Science Planetary Science Division The Solar System Explore More
6 min read NASA’s Dragonfly Mission Sets Sights on Titan’s Mysteries
Article
2 hours ago
4 min read Eclipses, Auroras, and the Spark of Becoming: NASA Inspires Future Scientists
Article
1 week ago
6 min read NASA Observes First Visible-light Auroras at Mars
Article
1 week ago
Keep Exploring Discover More Topics From NASA
Planetary Science Stories
Astromaterials
Latest NASA Science News
Solar System
View the full article
-
By NASA
5 Min Read Planetary Alignment Provides NASA Rare Opportunity to Study Uranus
Artist's illustration showing a distant star going out of sight as it is eclipsed by Uranus – an event known as a planetary stellar occultation. Credits: NASA/Advanced Concepts Laboratory When a planet’s orbit brings it between Earth and a distant star, it’s more than just a cosmic game of hide and seek. It’s an opportunity for NASA to improve its understanding of that planet’s atmosphere and rings. Planetary scientists call it a stellar occultation and that’s exactly what happened with Uranus on April 7.
Observing the alignment allows NASA scientists to measure the temperatures and composition of Uranus’ stratosphere – the middle layer of a planet’s atmosphere – and determine how it has changed over the last 30 years since Uranus’ last significant occultation.
To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video
This rendering demonstrates what is happening during a stellar occultation and illustrates an example of the light curve data graph recorded by scientists that enables them to gather atmospheric measurements, like temperature and pressure, from Uranus as the amount of starlight changes when the planet eclipses the star.NASA/Advanced Concepts Laboratory “Uranus passed in front of a star that is about 400 light years from Earth,” said William Saunders, planetary scientist at NASA’s Langley Research Center in Hampton, Virginia, and science principal investigator and analysis lead, for what NASA’s team calls the Uranus Stellar Occultation Campaign 2025. “As Uranus began to occult the star, the planet’s atmosphere refracted the starlight, causing the star to appear to gradually dim before being blocked completely. The reverse happened at the end of the occultation, making what we call a light curve. By observing the occultation from many large telescopes, we are able to measure the light curve and determine Uranus’ atmospheric properties at many altitude layers.”
We are able to measure the light curve and determine Uranus' atmospheric properties at many altitude layers.
William Saunders
Planetary Scientist at NASA's Langley Research Center
This data mainly consists of temperature, density, and pressure of the stratosphere. Analyzing the data will help researchers understand how the middle atmosphere of Uranus works and could help enable future Uranus exploration efforts.
To observe the rare event, which lasted about an hour and was only visible from Western North America, planetary scientists at NASA Langley led an international team of over 30 astronomers using 18 professional observatories.
Kunio Sayanagi, NASA’s principal investigator for the Uranus Stellar Occultation Campaign 2025, meeting virtually with partners and observing data from the Flight Mission Support Center at NASA’s Langley Research Center in Hampton, Virginia during Uranus’ stellar occultation event on April 7, 2025.NASA/Dave MacDonnell “This was the first time we have collaborated on this scale for an occultation,” said Saunders. “I am extremely grateful to each member of the team and each observatory for taking part in this extraordinary event. NASA will use the observations of Uranus to determine how energy moves around the atmosphere and what causes the upper layers to be inexplicably hot. Others will use the data to measure Uranus’ rings, its atmospheric turbulence, and its precise orbit around the Sun.”
Knowing the location and orbit of Uranus is not as simple as it sounds. In 1986, NASA’s Voyager 2 spacecraft became the first and only spacecraft to fly past the planet – 10 years before the last bright stellar occultation occured in 1996. And, Uranus’ exact position in space is only accurate to within about 100 miles, which makes analyzing this new atmospheric data crucial to future NASA exploration of the ice giant.
These investigations were possible because the large number of partners provided many unique views of the stellar occultation from many different instruments.
NASA planetary scientist William Saunders and Texas A&M University research assistant Erika Cook in the control room of the McDonald Observatory’s Otto Struve Telescope in Jeff Davis County, Texas, during the Uranus stellar occultation on April 7, 2025.Joshua Santana Emma Dahl, a postdoctoral scholar at Caltech in Pasadena, California, assisted in gathering observations from NASA’s Infrared Telescope Facility (IRTF) on the summit of Mauna Kea in Hawaii – an observatory first built to support NASA’s Voyager missions.
“As scientists, we do our best work when we collaborate. This was a team effort between NASA scientists, academic researchers, and amateur astronomers,” said Dahl. “The atmospheres of the gas and ice giant planets [Jupiter, Saturn, Uranus, and Neptune] are exceptional atmospheric laboratories because they don’t have solid surfaces. This allows us to study cloud formation, storms, and wind patterns without the extra variables and effects a surface produces, which can complicate simulations very quickly.”
On November 12, 2024, NASA Langley researchers and collaborators were able to do a test run to prepare for the April occultation. Langley coordinated two telescopes in Japan and one in Thailand to observe a dimmer Uranus stellar occultation only visible from Asia. As a result, these observers learned how to calibrate their instruments to observe stellar occultations, and NASA was able to test its theory that multiple observatories working together could capture Uranus’ big event in April.
Researchers from the Paris Observatory and Space Science Institute, in contact with NASA, also coordinated observations of the November 2024 occultation from two telescopes in India. These observations of Uranus and its rings allowed the researchers, who were also members of the April 7 occultation team, to improve the predictions about the timing on April 7 down to the second and also improved modeling to update Uranus’ expected location during the occultation by 125 miles.
This image of Uranus from NIRCam (Near-Infrared Camera) on NASA’s James Webb Space Telescope exquisitely captures Uranus’s seasonal north polar cap and dim inner and outer rings. This Webb image also shows 9 of the planet’s 27 moons – clockwise starting at 2 o’clock, they are: Rosalind, Puck, Belinda, Desdemona, Cressida, Bianca, Portia, Juliet, and Perdita.NASA, ESA, CSA, STScI Uranus is almost 2 billion miles away from Earth and has an atmosphere composed of primarily hydrogen and helium. It does not have a solid surface, but rather a soft surface made of water, ammonia, and methane. It’s called an ice giant because its interior contains an abundance of these swirling fluids that have relatively low freezing points. And, while Saturn is the most well-known planet for having rings, Uranus has 13 known rings composed of ice and dust.
Over the next six years, Uranus will occult several dimmer stars. NASA hopes to gather airborne and possibly space-based measurements of the next bright Uranus occultation in 2031, which will be of an even brighter star than the one observed in April.
For more information on NASA’s Uranus Stellar Occultation Campaign 2025:
https://science.larc.nasa.gov/URANUS2025
Karen Fox / Molly Wasser
Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
Charles Hatfield
Langley Research Center, Hampton, Virginia
757-262-8289
charles.g.hatfield@nasa.gov
About the Author
Charles G. Hatfield
Science Public Affairs Officer, NASA Langley Research Center
Share
Details
Last Updated Apr 22, 2025 Related Terms
General Ice Giants Langley Research Center Planetary Science Division Uranus Explore More
4 min read NASA Tests Ultralight Antennas to Benefit Future National Airspace
Article 7 hours ago 3 min read Celebrating Earth as Only NASA Can
Article 1 day ago 3 min read NASA Studies Wind Effects and Aircraft Tracking with Joby Aircraft
Article 5 days ago Keep Exploring Discover More Topics From NASA
Missions
Humans in Space
Climate Change
Solar System
View the full article
-
-
By NASA
When Michael Ciancone joined NASA in 1983, he could hardly imagine what his 40-plus-year career would entail. From honoring and preserving spaceflight history to advancing safety standards, he has undoubtedly woven his knowledge and experience into NASA’s history as well as its future.
Ciancone currently serves as the Orion Program safety lead, overseeing the Office of Safety and Mission Assurance’s effort to ensure the safety of the Orion crew, vehicle, and associated hardware. In his role, he manages safety reviews of all flight hardware, with a current focus on Artemis II. His everyday success is backed by decades of learning and global collaboration within the areas of human spaceflight safety and history.
Michael Ciancone with Space Shuttle Atlantis at the launch gantry at NASA’s Kennedy Space Center in Florida in 2009. Image courtesy of Michael Ciancone In 1997, Ciancone transferred from NASA’s Glenn Research Center in Cleveland to Johnson Space Center in Houston to serve as the executive officer for the Shuttle/International Space Station Payload Safety Review Panel, as well as group lead for Payload Safety. To better understand the scope and nature of his new role, Ciancone sought opportunities to engage with other safety professionals at conferences and symposia. At the suggestion of his manager, Ciancone instead organized a conference on spaceflight safety for payloads at Johnson, creating a forum for colleagues from the international spaceflight community.
These efforts were the catalyst for the formation of the International Association for the Advancement of Spaceflight Safety (IAASS), an organization founded by Ciancone and Skip Larsen of Johnson along with Alex Soons and Tommaso Sgobba of the European Space Agency. The IAASS is committed to furthering international cooperation and scientific advancements in space system safety and is recognized as the pre-eminent international forum for spaceflight and safety professionals. The organization is responsible for hosting an annual conference, conducting specialized safety training, and publishing seminal books on the aspects of spaceflight safety.
Throughout his tenure, Ciancone has worked closely with colleagues from around the world and he emphasizes that human spaceflight is a global endeavor made possible through respect and collaboration. “[In human spaceflight] there are different and equally valid approaches for achieving a common goal. Successful partnership requires an understanding and respect for the experiences and history of international partners,” he said.
Michael Ciancone (far left) pictured with Spaceflight Safety team members from NASA, the European Space Agency (ESA), and Airbus during a joint NASA/ESA safety review of the European Service Module (ESM) of the Orion Program at the Airbus facility in Bremen, Germany. Image courtesy of Michael Ciancone In addition to his dedication to spaceflight safety, Ciancone is active in the field of spaceflight history. He serves as the chair of the History Committee of the American Astronautical Society and, as a member of the International Academy of Astronautics, he also serves on the History Committee. Working in this community has made Ciancone more keenly aware of dreams of spaceflight as viewed from a historical perspective and guides his daily work at NASA.
Michael Ciancone (left) with Giovanni Caprara, science editor for the Corriere della Sera and co-author of “Early Italian Contributions to Astronautics: From the First Visionary to Construction of the first Italian Liquid Propellant Rocket” during the 75th International Astronautical Congress in Milan, Italy. Image courtesy of Michael Ciancone Beyond his technical achievements, Ciancone has also found creative ways to spice up the spaceflight community. While at Glenn Research Center, he co-founded the NASA Hot Pepper Club—a forum for employees who share a passion for cultivating and consuming hot peppers and pepper products. The club served as a unique space for camaraderie and connection, adding flavor to NASA life.
Ciancone’s immersion in spaceflight history and spaceflight safety has shaped his unique and valuable perspective. In addition to encouraging others to embrace new challenges and opportunities, Ciancone paraphrases Albert Einstein to advise the Artemis Generation to “learn from the past, live in the moment, and dream of the future.” This mentality has enabled him to combine his interest in spaceflight history with his work on Orion over the past 15 years, laying the groundwork for what he refers to as “future history.”
View the full article
-
By NASA
2 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
NASA is bringing the world of planetary defense to the public with its new documentary, “Planetary Defenders.”
Dr. Shantanu Naidu, Asteroid Radar Researcher, from NASA’s Jet Propulsion Laboratory points toward the Goldstone Solar System Radar in Barstow, CA – the most powerful planetary radar on Earth.Credit: NASA What would humanity do if an asteroid were headed for Earth? The documentary takes viewers inside the real-life efforts of scientists and engineers working to detect, track, and mitigate potential asteroid threats. Featuring firsthand accounts from experts on the front lines, the film reveals the science, technology, and personal dedication behind planetary defense. The film also showcases the teamwork that drives this critical global effort.
Debuting on NASA+ Wednesday, April 16, NASA is inviting the public to participate in a special YouTube Premiere event at 4:30 p.m. EDT. During this interactive screening, viewers can watch the first public showing of the film together and ask questions to NASA planetary defense experts.
To engage audiences further, NASA is providing digital creators with a toolkit that includes resources, activities, and ways to join the mission of planetary defense.
Established in 2016, NASA’s Planetary Defense Coordination Office leads the agency’s mission to find, track, and understand asteroids and comets that could pose a risk to Earth.
Stay up to date on NASA’s planetary defense efforts: https://www.nasa.gov/planetarydefense
About the Author
Emily Furfaro
Share
Details
Last Updated Apr 09, 2025 Related Terms
General Planetary Defense Planetary Defense Coordination Office Planetary Science Division Science Mission Directorate Explore More
2 min read Welcome to the Mission Support Directorate
Article 19 hours ago 7 min read Eclipses, Science, NASA Firsts: Heliophysics Big Year Highlights
One year ago today, a total solar eclipse swept across the United States. The event…
Article 1 day ago 3 min read Meet Alex Olley: Air Force Veteran Powering the Space Station
Article 1 day ago Keep Exploring Discover More Topics From NASA
Missions
Humans in Space
Climate Change
Solar System
View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.