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By NASA
6 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Sunlight reflects off the ocean surface near Norfolk, Virginia, in this 1991 space shuttle image, highlighting swirling patterns created by features such as internal waves, which are produced when the tide moves over underwater features. Data from the international SWOT mission is revealing the role of smaller-scale waves and eddies.NASA The international mission collects two-dimensional views of smaller waves and currents that are bringing into focus the ocean’s role in supporting life on Earth.
Small things matter, at least when it comes to ocean features like waves and eddies. A recent NASA-led analysis using data from the SWOT (Surface Water and Ocean Topography) satellite found that ocean features as small as a mile across potentially have a larger impact on the movement of nutrients and heat in marine ecosystems than previously thought.
Too small to see well with previous satellites but too large to see in their entirety with ship-based instruments, these relatively small ocean features fall into a category known as the submesoscale. The SWOT satellite, a joint effort between NASA and the French space agency CNES (Centre National d’Études Spatiales), can observe these features and is demonstrating just how important they are, driving much of the vertical transport of things like nutrients, carbon, energy, and heat within the ocean. They also influence the exchange of gases and energy between the ocean and atmosphere.
“The role that submesoscale features play in ocean dynamics is what makes them important,” said Matthew Archer, an oceanographer at NASA’s Jet Propulsion Laboratory in Southern California. Some of these features are called out in the animation below, which was created using SWOT sea surface height data.
This animation shows small ocean features — including internal waves and eddies — derived from SWOT observations in the Indian, Atlantic, and Pacific oceans, as well as the Mediterranean Sea. White and lighter blue represent higher ocean surface heights compared to darker blue areas. The purple colors shown in one location represent ocean current speeds.
NASA’s Scientific Visualization Studio “Vertical currents move heat between the atmosphere and ocean, and in submesoscale eddies, can actually bring up heat from the deep ocean to the surface, warming the atmosphere,” added Archer, who is a coauthor on the submesoscale analysis published in April in the journal Nature. Vertical circulation can also bring up nutrients from the deep sea, supplying marine food webs in surface waters like a steady stream of food trucks supplying festivalgoers.
“Not only can we see the surface of the ocean at 10 times the resolution of before, we can also infer how water and materials are moving at depth,” said Nadya Vinogradova Shiffer, SWOT program scientist at NASA Headquarters in Washington.
Fundamental Force
Researchers have known about these smaller eddies, or circular currents, and waves for decades. From space, Apollo astronauts first spotted sunlight glinting off small-scale eddies about 50 years ago. And through the years, satellites have captured images of submesoscale ocean features, providing limited information such as their presence and size. Ship-based sensors or instruments dropped into the ocean have yielded a more detailed view of submesoscale features, but only for relatively small areas of the ocean and for short periods of time.
The SWOT satellite measures the height of water on nearly all of Earth’s surface, including the ocean and freshwater bodies, at least once every 21 days. The satellite gives researchers a multidimensional view of water levels, which they can use to calculate, for instance, the slope of a wave or eddy. This in turn yields information on the amount of pressure, or force, being applied to the water in the feature. From there, researchers can figure out how fast a current is moving, what’s driving it and —combined with other types of information — how much energy, heat, or nutrients those currents are transporting.
“Force is the fundamental quantity driving fluid motion,” said study coauthor Jinbo Wang, an oceanographer at Texas A&M University in College Station. Once that quantity is known, a researcher can better understand how the ocean interacts with the atmosphere, as well as how changes in one affect the other.
Prime Numbers
Not only was SWOT able to spot a submesoscale eddy in an offshoot of the Kuroshio Current — a major current in the western Pacific Ocean that flows past the southeast coast of Japan — but researchers were also able to estimate the speed of the vertical circulation within that eddy. When SWOT observed the feature, the vertical circulation was likely 20 to 45 feet (6 to 14 meters) per day.
This is a comparatively small amount for vertical transport. However, the ability to make those calculations for eddies around the world, made possible by SWOT, will improve researchers’ understanding of how much energy, heat, and nutrients move between surface waters and the deep sea.
Researchers can do similar calculations for such submesoscale features as an internal solitary wave — a wave driven by forces like the tide sloshing over an underwater plateau. The SWOT satellite spotted an internal wave in the Andaman Sea, located in the northeastern part of the Indian Ocean off Myanmar. Archer and colleagues calculated that the energy contained in that solitary wave was at least twice the amount of energy in a typical internal tide in that region.
This kind of information from SWOT helps researchers refine their models of ocean circulation. A lot of ocean models were trained to show large features, like eddies hundreds of miles across, said Lee Fu, SWOT project scientist at JPL and a study coauthor. “Now they have to learn to model these smaller scale features. That’s what SWOT data is helping with.”
Researchers have already started to incorporate SWOT ocean data into some models, including NASA’s ECCO (Estimating the Circulation and Climate of the Ocean). It may take some time until SWOT data is fully a part of models like ECCO. But once it is, the information will help researchers better understand how the ocean ecosystem will react to a changing world.
More About SWOT
The SWOT satellite was jointly developed by NASA and CNES, with contributions from the Canadian Space Agency (CSA) and the UK Space Agency. Managed for NASA by Caltech in Pasadena, California, JPL leads the U.S. component of the project. For the flight system payload, NASA provided the Ka-band radar interferometer (KaRIn) instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations. The Doppler Orbitography and Radioposition Integrated by Satellite system, the dual frequency Poseidon altimeter (developed by Thales Alenia Space), the KaRIn radio-frequency subsystem (together with Thales Alenia Space and with support from the UK Space Agency), the satellite platform, and ground operations were provided by CNES. The KaRIn high-power transmitter assembly was provided by CSA.
To learn more about SWOT, visit:
https://swot.jpl.nasa.gov
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Last Updated May 15, 2025 Related Terms
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6 min read NASA’s Magellan Mission Reveals Possible Tectonic Activity on Venus
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By NASA
1 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Will the Sun ever burn out?
Well, the Sun, just like the stars we see at night, is a star. It’s a giant ball of super hot hydrogen.
Gravity squeezes it in and it creates energy, which is what makes the Sun shine. Eventually, it will use up all of that hydrogen. But in the process, it’s creating helium. So it will then use the helium. And it will continue to use larger and larger elements until it can’t do this anymore.
And when that happens, it will start to expand into a red giant about the size of the inner planets. Then it will shrink back down into a very strange star called a white dwarf — super hot, but not very bright and about the size of the Earth.
But our Sun has a pretty long lifetime. It’s halfway through its 10-billion-year lifetime.
So the Sun will never really burn out, but it will change and be a very, very different dim kind of star when it reaches the end of its normal life.
[END VIDEO TRANSCRIPT]
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4 min read Eclipses, Auroras, and the Spark of Becoming: NASA Inspires Future Scientists
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By NASA
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NASA Observes First Visible-light Auroras at Mars
On March 15, 2024, near the peak of the current solar cycle, the Sun produced a solar flare and an accompanying coronal mass ejection (CME), a massive explosion of gas and magnetic energy that carries with it large amounts of solar energetic particles. This solar activity led to stunning auroras across the solar system, including at Mars, where NASA’s Perseverance Mars rover made history by detecting them for the first time from the surface of another planet.
The first visible-light image of green aurora on Mars (left), taken by the Mastcam-Z instrument on NASA’s Perseverance Mars rover. On the right is a comparison image of the night sky of Mars without aurora but featuring the Martian moon Deimos. The moonlit Martian night sky, lit up mostly by Mars’ nearer and larger moon Phobos (outside the frame) has a reddish-brown hue due to the dust in the atmosphere, so when green auroral light is added, the sky takes on a green-yellow tone, as seen in the left image. NASA/JPL-Caltech/ASU/MSSS/SSI “This exciting discovery opens up new possibilities for auroral research and confirms that auroras could be visible to future astronauts on Mars’ surface.” said Elise Knutsen, a postdoctoral researcher at the University of Oslo in Norway and lead author of the Science Advances study, which reported the detection.
Picking the right aurora
On Earth, auroras form when solar particles interact with the global magnetic field, funneling them to the poles where they collide with atmospheric gases and emit light. The most common color, green, is caused by excited oxygen atoms emitting light at a wavelength of 557.7 nanometers. For years, scientists have theorized that green light auroras could also exist on Mars but suggested they would be much fainter and harder to capture than the green auroras we see on Earth.
Due to the Red Planet’s lack of a global magnetic field, Mars has different types of auroras than those we have on Earth. One of these is solar energetic particle (SEP) auroras, which NASA’s MAVEN (Mars Atmosphere and Volatile EvolutioN) mission discovered in 2014. These occur when super-energetic particles from the Sun hit the Martian atmosphere, causing a reaction that makes the atmosphere glow across the whole night sky.
While MAVEN had observed SEP auroras in ultraviolet light from orbit, this phenomenon had never been observed in visible light from the ground. Since SEPs typically occur during solar storms, which increase during solar maximum, Knutsen and her team set their sights on capturing visible images and spectra of SEP aurora from Mars’ surface at the peak of the Sun’s current solar cycle.
Coordinating the picture-perfect moment
Through modeling, Knutsen and her team determined the optimal angle for the Perseverance rover’s SuperCam spectrometer and Mastcam-Z camera to successfully observe the SEP aurora in visible light. With this observation strategy in place, it all came down to the timing and understanding of CMEs.
“The trick was to pick a good CME, one that would accelerate and inject many charged particles into Mars’ atmosphere,” said Knutsen.
That is where the teams at NASA’s Moon to Mars (M2M) Space Weather Analysis Office and the Community Coordinated Modeling Center (CCMC), both located at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, came in. The M2M team provides real-time analysis of solar eruptions to the CCMC for initiating simulations of CMEs to determine if they might impact current NASA missions. When the simulations suggest potential impacts, the team sends out an alert.
At the University of California, Berkeley, space physicist Christina Lee received an alert from the M2M office about the March 15, 2024, CME. Lee, a member of the MAVEN mission team who serves as the space weather lead, determined there was a notable solar storm heading toward the Red Planet,which could arrive in a few days. She immediately issued the Mars Space Weather Alert Notification to currently operating Mars missions.
“This allows the science teams of Perseverance and MAVEN to anticipate impacts of interplanetary CMEs and the associated SEPs,” said Lee.
“When we saw the strength of this one,” Knutsen said, “we estimated it could trigger aurora bright enough for our instruments to detect.”
A few days later, the CME impacted Mars, providing a lightshow for the rover to capture, showing the aurora to be nearly uniform across the sky at an emission wavelength of exactly 557.7 nm. To confirm the presence of SEPs during the aurora observation, the team looked to MAVEN’s SEP instrument, which was additionally corroborated by data from ESA’s (European Space Agency) Mars Express mission. Data from both missions confirmed that the rover team had managed to successfully catch a glimpse of the phenomenon in the very narrow time window available.
“This was a fantastic example of cross-mission coordination. We all worked together quickly to facilitate this observation and are thrilled to have finally gotten a sneak peek of what astronauts will be able to see there some day,” said Shannon Curry, MAVEN principal investigator and research scientist at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder (CU Boulder).
The future of aurora on Mars
By coordinating the Perseverance observations with measurements from MAVEN’s SEP instrument, the teams could help each other determine that the observed 557.7 nm emission came from solar energetic particles. Since this is the same emission line as the green aurora on Earth, it is likely that future Martian astronauts would be able to see this type of aurora.
“Perseverance’s observations of the visible-light aurora confirm a new way to study these phenomena that’s complementary to what we can observe with our Mars orbiters,” said Katie Stack Morgan, acting project scientist for Perseverance at NASA’s Jet Propulsion Laboratory in Southern California. “A better understanding of auroras and the conditions around Mars that lead to their formation are especially important as we prepare to send human explorers there safely.”
On September 21, 2014, NASA’s MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft entered orbit around Mars. The mission has produced a wealth of data about how Mars’ atmosphere responds to the Sun and solar wind NASA/JPL-Caltech More About Perseverance and MAVEN
The Mars 2020 Perseverance mission is part of NASA’s Mars Exploration Program portfolio and NASA’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet. NASA’s Jet Propulsion Laboratory, which is managed for the agency by Caltech, built and manages operations of the Perseverance rover.
The MAVEN mission, also part of NASA’s Mars Exploration Program portfolio, is led by LASP at CU Boulder. It’s managed by NASA’s Goddard Space Flight Center and was built and operated by Lockheed Martin Space, with navigation and network support from NASA’s JPL.
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By Willow Reed
Laboratory for Atmospheric and Space Physics (LASP), University of Colorado Boulder
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By NASA
6 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
New research suggests vast surface features on Venus called coronae continue to be shaped by tectonic processes. Observations of these features from NASA’s Magellan mission include, clockwise from top left, Artemis Corona, Quetzalpetlatl Corona, Bahet Corona, and Aine Corona.NASA/JPL-Caltech Using archival data from the mission, launched in 1989, researchers have uncovered new evidence that tectonic activity may be deforming the planet’s surface.
Vast, quasi-circular features on Venus’ surface may reveal that the planet has ongoing tectonics, according to new research based on data gathered more than 30 years ago by NASA’s Magellan mission. On Earth, the planet’s surface is continually renewed by the constant shifting and recycling of massive sections of crust, called tectonic plates, that float atop a viscous interior. Venus doesn’t have tectonic plates, but its surface is still being deformed by molten material from below.
Seeking to better understand the underlying processes driving these deformations, the researchers studied a type of feature called a corona. Ranging in size from dozens to hundreds of miles across, a corona is most often thought to be the location where a plume of hot, buoyant material from the planet’s mantle rises, pushing against the lithosphere above. (The lithosphere includes the planet’s crust and the uppermost part of its mantle.) These structures are usually oval, with a concentric fracture system surrounding them. Hundreds of coronae are known to exist on Venus.
Published in the journal Science Advances, the new study details newly discovered signs of activity at or beneath the surface shaping many of Venus’ coronae, features that may also provide a unique window into Earth’s past. The researchers found the evidence of this tectonic activity within data from NASA’s Magellan mission, which orbited Venus in the 1990s and gathered the most detailed gravity and topography data on the planet currently available.
“Coronae are not found on Earth today; however, they may have existed when our planet was young and before plate tectonics had been established,” said the study’s lead author, Gael Cascioli, assistant research scientist at the University of Maryland, Baltimore County, and NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “By combining gravity and topography data, this research has provided a new and important insight into the possible subsurface processes currently shaping the surface of Venus.”
This artist’s concept of the large Quetzalpetlatl Corona located in Venus’ southern hemisphere depicts active volcanism and a subduction zone, where the foreground crust plunges into the planet’s interior. A new study suggests coronae are the locations of several types of tectonic activity.NASA/JPL-Caltech/Peter Rubin As members of NASA’s forthcoming VERITAS (Venus Emissivity, Radio science, InSAR, Topography, and Spectroscopy) mission, Cascioli and his team are particularly interested in the high-resolution gravity data the spacecraft will provide. Study coauthor Erwan Mazarico, also at Goddard, will co-lead the VERITAS gravity experiment when the mission launches no earlier than 2031.
Mystery Coronae
Managed by NASA’s Jet Propulsion Laboratory in Southern California, Magellan used its radar system to see through Venus’ thick atmosphere and map the topography of its mountains and plains. Of the geological features the spacecraft mapped, coronae were perhaps the most enigmatic: It wasn’t clear how they formed. In the years since, scientists have found many coronae in locations where the planet’s lithosphere is thin and heat flow is high.
“Coronae are abundant on Venus. They are very large features, and people have proposed different theories over the years as to how they formed,” said coauthor Anna Gülcher, Earth and planetary scientist at the University of Bern in Switzerland. “The most exciting thing for our study is that we can now say there are most likely various and ongoing active processes driving their formation. We believe these same processes may have occurred early in Earth’s history.”
The researchers developed sophisticated 3D geodynamic models that demonstrate various formation scenarios for plume-induced coronae and compared them with the combined gravity and topography data from Magellan. The gravity data proved crucial in helping the researchers detect less dense, hot, and buoyant plumes under the surface — information that couldn’t be discerned from topography data alone. Of the 75 coronae studied, 52 appear to have buoyant mantle material beneath them that is likely driving tectonic processes.
One key process is subduction: On Earth, it happens when the edge of one tectonic plate is driven beneath the adjacent plate. Friction between the plates can generate earthquakes, and as the old rocky material dives into the hot mantle, the rock melts and is recycled back to the surface via volcanic vents.
These illustrations depict various types of tectonic activity thought to persist beneath Venus’ coronae. Lithospheric dripping and subduction are shown at top; below are and two scenarios where hot plume material rises and pushes against the lithosphere, potentially driving volcanism above it.Anna Gülcher, CC BY-NC On Venus, a different kind of subduction is thought to occur around the perimeter of some coronae. In this scenario, as a buoyant plume of hot rock in the mantle pushes upward into the lithosphere, surface material rises and spreads outward, colliding with surrounding surface material and pushing that material downward into the mantle.
Another tectonic process known as lithospheric dripping could also be present, where dense accumulations of comparatively cool material sink from the lithosphere into the hot mantle. The researchers also identify several places where a third process may be taking place: A plume of molten rock beneath a thicker part of the lithosphere potentially drives volcanism above it.
Deciphering Venus
This work marks the latest instance of scientists returning to Magellan data to find that Venus exhibits geologic processes that are more Earth-like than originally thought. Recently, researchers were able to spot erupting volcanoes, including vast lava flows that vented from Maat Mons, Sif Mons, and Eistla Regio in radar images from the orbiter.
While those images provided direct evidence of volcanic action, the authors of the new study will need sharper resolution to draw a complete picture about the tectonic processes driving corona formation. “The VERITAS gravity maps of Venus will boost the resolution by at least a factor of two to four, depending on location — a level of detail that could revolutionize our understanding of Venus’ geology and implications for early Earth,” said study coauthor Suzanne Smrekar, a planetary scientist at JPL and principal investigator for VERITAS.
Managed by JPL, VERITAS will use a synthetic aperture radar to create 3D global maps and a near-infrared spectrometer to figure out what the surface of Venus is made of. Using its radio tracking system, the spacecraft will also measure the planet’s gravitational field to determine the structure of Venus’ interior. All of these instruments will help pinpoint areas of activity on the surface.
For more information about NASA’s VERITAS mission, visit:
https://science.nasa.gov/mission/veritas/
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Last Updated May 14, 2025 Related Terms
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6 min read NASA Studies Reveal Hidden Secrets About Interiors of Moon, Vesta
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By NASA
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Preparations for Next Moonwalk Simulations Underway (and Underwater)
This artist’s concept shows the Moon’s hot interior and volcanism about 2 to 3 billion years ago. It is thought that volcanic activity on the lunar near side (the side facing Earth) helped create a landscape dominated by vast plains called mare, which are formed by molten rock that cooled and solidified. NASA/JPL-Caltech Analyzing gravity data collected by spacecraft orbiting other worlds reveals groundbreaking insights about planetary structures without having to land on the surface.
Although the Moon and the asteroid Vesta are very different, two NASA studies use the same technique to reveal new details about the interiors of both.
In the lunar study, published May 14 in the journal Nature, researchers developed a new gravity model of the Moon that includes tiny variations in the celestial body’s gravity during its elliptical orbit around Earth. These fluctuations cause the Moon to flex slightly due to Earth’s tidal force — a process called tidal deformation — which provides critical insights into the Moon’s deep internal structure.
Using their model, the researchers produced the most detailed lunar gravitational map yet, providing future missions an improved way to calculate location and time on the Moon. They accomplished this by analyzing data on the motion of NASA’s GRAIL (Gravity Recovery and Interior Laboratory) mission, whose spacecraft, Ebb and Flow, orbited the Moon from Dec. 31, 2011, to Dec. 17, 2012.
These views of the Moon’s near side, left, and far side were put together from observations made by NASA’s Lunar Reconnaissance Orbiter. NASA/JPL-Caltech In a second study, published in the journal Nature Astronomy on April 23, the researchers focused on Vesta, an object in the main asteroid belt between Mars and Jupiter. Using NASA’s Deep Space Network radiometric data and imaging data from the agency’s Dawn spacecraft, which orbited the asteroid from July 16, 2011, to Sept. 5, 2012, they found that instead of having distinct layers as expected, Vesta’s internal structure may be mostly uniform, with a very small iron core or no core at all.
“Gravity is a unique and fundamental property of a planetary body that can be used to explore its deep interior,” said Park. “Our technique doesn’t need data from the surface; we just need to track the motion of the spacecraft very precisely to get a global view of what’s inside.”
Lunar Asymmetry
The lunar study looked at gravitational changes to the Moon’s near and far sides. While the near side is dominated by vast plains — known as mare — formed by molten rock that cooled and solidified billions of years ago, the far side is more rugged, with few plains.
NASA’s Dawn mission obtained this image of the giant asteroid Vesta on July 24, 2011. The spacecraft spent 14 months orbiting the asteroid, capturing more than 30,000 images and fully mapping its surface. NASA/JPL-Caltech/UCLA/MPS/DLR/IDA Both studies were led by Ryan Park, supervisor of the Solar System Dynamics Group at NASA’s Jet Propulsion Laboratory in Southern California, and were years in the making due to their complexity. The team used NASA supercomputers to build a detailed map of how gravity varies across each body. From that, they could better understand what the Moon and Vesta are made of and how planetary bodies across the solar system formed.
Some theories suggest intense volcanism on the near side likely caused these differences. That process would have caused radioactive, heat-generating elements to accumulate deep inside the near side’s mantle, and the new study offers the strongest evidence yet that this is likely the case.
“We found that the Moon’s near side is flexing more than the far side, meaning there’s something fundamentally different about the internal structure of the Moon’s near side compared to its far side,” said Park. “When we first analyzed the data, we were so surprised by the result we didn’t believe it. So we ran the calculations many times to verify the findings. In all, this is a decade of work.”
When comparing their results with other models, Park’s team found a small but greater-than-expected difference in how much the two hemispheres deform. The most likely explanation is that the near side has a warm mantle region, indicating the presence of heat-generating radioactive elements, which is evidence for volcanic activity that shaped the Moon’s near side 2 billion to 3 billion years ago.
Vesta’s Evolution
Park’s team applied a similar approach for their study that focused on Vesta’s rotational properties to learn more about its interior.
“Our technique is sensitive to any changes in the gravitational field of a body in space, whether that gravitational field changes over time, like the tidal flexing of the Moon, or through space, like a wobbling asteroid,” said Park. “Vesta wobbles as it spins, so we could measure its moment of inertia, a characteristic that is highly sensitive to the internal structure of the asteroid.”
Changes in inertia can be seen when an ice skater spins with their arms held outward. As they pull their arms in, bringing more mass toward their center of gravity, their inertia decreases and their spin speeds up. By measuring Vesta’s inertia, scientists can gain a detailed understanding of the distribution of mass inside the asteroid: If its inertia is low, there would be a concentration of mass toward its center; if it’s high, the mass would be more evenly distributed.
Some theories suggest that over a long period, Vesta gradually formed onion-like layers and a dense core. But the new inertia measurement from Park’s team suggests instead that Vesta is far more homogeneous, with its mass distributed evenly throughout and only a small core of dense material, or no core.
Gravity slowly pulls the heaviest elements to a planet’s center over time, which is how Earth ended up with a dense core of liquid iron. While Vesta has long been considered a differentiated asteroid, a more homogenous structure would suggest that it may not have fully formed layers or may have formed from the debris of another planetary body after a massive impact.
In 2016, Park used the same data types as the Vesta study to focus on Dawn’s second target, the dwarf planet Ceres, and results suggested a partially differentiated interior.
Park and his team recently applied a similar technique to Jupiter’s volcanic moon Io, using data acquired by NASA’s Juno and Galileo spacecraft during their flybys of the Jovian satellite as well as from ground-based observations. By measuring how Io’s gravity changes as it orbits Jupiter, which exerts a powerful tidal force, they revealed that the fiery moon is unlikely to possess a global magma ocean.
“Our technique isn’t restricted just to Io, Ceres, Vesta, or the Moon,” said Park. “There are many opportunities in the future to apply our technique for studying the interiors of intriguing planetary bodies throughout the solar system.”
News Media Contacts
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Last Updated May 14, 2025 Related Terms
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