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By NASA
5 Min Read Making Mars’ Moons: Supercomputers Offer ‘Disruptive’ New Explanation
A NASA study using a series of supercomputer simulations reveals a potential new solution to a longstanding Martian mystery: How did Mars get its moons? The first step, the findings say, may have involved the destruction of an asteroid.
The research team, led by Jacob Kegerreis, a postdoctoral research scientist at NASA’s Ames Research Center in California’s Silicon Valley, found that an asteroid passing near Mars could have been disrupted – a nice way of saying “ripped apart” – by the Red Planet’s strong gravitational pull.
The team’s simulations show the resulting rocky fragments being strewn into a variety of orbits around Mars. More than half the fragments would have escaped the Mars system, but others would’ve stayed in orbit. Tugged by the gravity of both Mars and the Sun, in the simulations some of the remaining asteroid pieces are set on paths to collide with one another, every encounter further grinding them down and spreading more debris.
Many collisions later, smaller chunks and debris from the former asteroid could have settled into a disk encircling the planet. Over time, some of this material is likely to have clumped together, possibly forming Mars’ two small moons, Phobos and Deimos.
To assess whether this was a realistic chain of events, the research team explored hundreds of different close encounter simulations, varying the asteroid’s size, spin, speed, and distance at its closest approach to the planet. The team used their high-performance, open-source computing code, called SWIFT, and the advanced computing systems at Durham University in the United Kingdom to study in detail both the initial disruption and, using another code, the subsequent orbits of the debris.
In a paper published Nov. 20 in the journal Icarus, the researchers report that, in many of the scenarios, enough asteroid fragments survive and collide in orbit to serve as raw material to form the moons.
“It’s exciting to explore a new option for the making of Phobos and Deimos – the only moons in our solar system that orbit a rocky planet besides Earth’s,” said Kegerreis. “Furthermore, this new model makes different predictions about the moons’ properties that can be tested against the standard ideas for this key event in Mars’ history.”
Two hypotheses for the formation of the Martian moons have led the pack. One proposes that passing asteroids were captured whole by Mars’ gravity, which could explain the moons’ somewhat asteroid-like appearance. The other says that a giant impact on the planet blasted out enough material – a mix of Mars and impactor debris – to form a disk and, ultimately, the moons. Scientists believe a similar process formed Earth’s Moon.
The latter explanation better accounts for the paths the moons travel today – in near-circular orbits that closely align with Mars’ equator. However, a giant impact ejects material into a disk that, mostly, stays close to the planet. And Mars’ moons, especially Deimos, sit quite far away from the planet and probably formed out there, too.
“Our idea allows for a more efficient distribution of moon-making material to the outer regions of the disk,” said Jack Lissauer, a research scientist at Ames and co-author on the paper. “That means a much smaller ‘parent’ asteroid could still deliver enough material to send the moons’ building blocks to the right place.”
It’s exciting to explore a new option for the making of Phobos and Deimos – the only moons in our solar system that orbit a rocky planet besides Earth’s.
Jacob Kegerreis
Postdoctoral research scientist at NASA’s Ames Research Center
Testing different ideas for the formation of Mars’ moons is the primary goal of the upcoming Martian Moons eXploration (MMX) sample return mission led by JAXA (Japan Aerospace Exploration Agency). The spacecraft will survey both moons to determine their origin and collect samples of Phobos to bring to Earth for study. A NASA instrument on board, called MEGANE – short for Mars-moon Exploration with GAmma rays and Neutrons – will identify the chemical elements Phobos is made of and help select sites for the sample collection. Some of the samples will be collected by a pneumatic sampler also provided by NASA as a technology demonstration contribution to the mission. Understanding what the moons are made of is one clue that could help distinguish between the moons having an asteroid origin or a planet-plus-impactor source.
Before scientists can get their hands on a piece of Phobos to analyze, Kegerreis and his team will pick up where they left off demonstrating the formation of a disk that has enough material to make Phobos and Deimos.
“Next, we hope to build on this proof-of-concept project to simulate and study in greater detail the full timeline of formation,” said Vincent Eke, associate professor at the Institute for Computational Cosmology at Durham University and a co-author on the paper. “This will allow us to examine the structure of the disk itself and make more detailed predictions for what the MMX mission could find.”
For Kegerreis, this work is exciting because it also expands our understanding of how moons might be born – even if it turns out that Mars’ own formed by a different route. The simulations offer a fascinating exploration, he says, of the possible outcomes of encounters between objects like asteroids and planets. These events were common in the early solar system, and simulations could help researchers reconstruct the story of how our cosmic backyard evolved.
This research is a collaborative effort between Ames and Durham University, supported by the Institute for Computational Cosmology’s Planetary Giant Impact Research group. The simulations used were run using the open-source SWIFT code, carried out on the DiRAC (Distributed Research Utilizing Advanced Computing) Memory Intensive service (“COSMA”), hosted by Durham University on behalf of the DiRAC High-Performance Computing facility.
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Members of the news media interested in covering this topic should reach out to the NASA Ames newsroom.
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Last Updated Nov 20, 2024 Related Terms
Mars Ames Research Center Ames Research Center's Science Directorate General High-Tech Computing Mars Moons Martian Moon Exploration (MMX) Missions NASA Centers & Facilities Planets Technology The Solar System Explore More
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By USH
While observing the Orion Nebula with his 12-inch Dobsonian telescope, a sky-watcher noticed an unusual flashing object. As stars appeared to drift due to Earth's rotation, this particular object while flashing approximately every 20 seconds clearly travels through deep space.
The observer wonders whether it might be a rotating satellite or not. However, this isn’t the first sighting of cigar-shaped UFOs or other mysterious objects traveling through space near the Orion Nebula, so it is quite possible that it could be an interstellar craft.
Over the years, I have shared several articles, complete with images and videos, documenting similar UFO sightings around the Orion Nebula. You can explore these under the tag: Orion Nebula.
Interestingly, these sightings have all occurred between November and February, suggesting there may be a seasonal pattern to these observations.
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By NASA
Curiosity Navigation Curiosity Home Mission Overview Where is Curiosity? Mission Updates Science Overview Instruments Highlights Exploration Goals News and Features Multimedia Curiosity Raw Images Images Videos Audio Mosaics More Resources Mars Missions Mars Sample Return Mars Perseverance Rover Mars Curiosity Rover MAVEN Mars Reconnaissance Orbiter Mars Odyssey More Mars Missions The Solar System The Sun Mercury Venus Earth The Moon Mars Jupiter Saturn Uranus Neptune Pluto & Dwarf Planets Asteroids, Comets & Meteors The Kuiper Belt The Oort Cloud 3 min read
Sols 4352-4354: Halloween Fright Night on Mars
NASA’s Mars rover Curiosity acquired this image of the target surface feature nicknamed “Reds Meadow,” using its Mars Hand Lens Imager (MAHLI), located on the turret at the end of the rover’s robotic arm. Curiosity captured the image Oct. 31, 2024, at 19:09:10 UTC, on sol 4350 — Martian day 4,350 of the Mars Science Laboratory Mission. NASA/JPL-Caltech/MSSS Earth planning date: Friday, Nov. 1, 2024
Yesterday evening (Thursday) was Halloween for many of us here on Earth. My neighborhood in eastern Canada was full of small (and not so small!) children, running around in the dark collecting sweets and candy but also getting scared by the ghostly decorations hung at each house. Little did we suspect that our poor rover on Mars was also getting spooked. Curiosity completed about a meter (about 3 feet) of the planned drive before becoming unsettled … scared, if you will! … when its left front wheel got hung up on a rock and stopped moving.
Luckily, we understood this kind of frightened behavior and were able to resume planning today as per usual. That meter was enough to give us a whole new set of targets to choose from. As APXS Strategic Planner this week, I had chosen darker-looking targets in the workspace — “Ladder Lake” and “Reds Meadow” (shown in the accompanying MAHLI image) — earlier in the week. I was happy that bumping backwards by a meter allowed us to reach some of the more typical pale colored bedrock at “Eureka Valley” and a second APXS analysis on “Black Bear Lake,” which is a mixture of both pale bedrock and some darker layers. MAHLI added in a bonus set of images on “Stag Dome,” focusing on small, rougher patches on the pale bedrock.
ChemCam is taking advantage of the short bump, too, adding a passive observation on the brushed Reds Meadow target, analyzed by APXS and MAHLI in Monday’s plan. A ChemCam LIBS target “Hoist Ridge” focuses on a small vertical face of dark material. Two long distance images planned for ChemCam’s Remote Micro Imager (RMI) look at the distribution of rocks along the Gediz Vallis ridge in the distance.
Mastcam is taking several mosaics this weekend (must have gotten extra energy from the Halloween sugar!). Close to the rover, Mastcam will acquire single-frame images of the targets Hoist Ridge and Eureka Valley, and a small mosaic of some surficial troughs just a little further away. Moving further afield, a small 3×1 mosaic (three images in one row) will image the same area as the ChemCam RMI of the Gediz Vallis ridge, and a larger 9×2 mosaic will focus on the faraway yardang unit, where we hopefully will be in a few years.
Then for the really big images: Mastcam will image the whole landscape in a special 360-degree view, so big it needs to be broken into two parts. The first will have 43×4 frames, the second 34×5 frames. These mosaics are huge, so we save them for when we are at a really good vantage point to allow us to capture as much detail as possible for science and engineering planning.
As ever, we continue our environmental monitoring of conditions, with Mastcam and Navcam movies and images looking at dust in the atmosphere above and around us in Gale crater, and watching out for dust devils.
Written by Catherine O’Connell-Cooper, Planetary Geologist at University of New Brunswick
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Last Updated Nov 04, 2024 Related Terms
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By NASA
3 Min Read November’s Night Sky Notes: Snowballs from Space
This diagram compares the size of the icy, solid nucleus of comet C/2014 UN271 (Bernardinelli-Bernstein) to several other comets. The majority of comet nuclei observed are smaller than Halley’s comet. They are typically a mile across or less. Comet C/2014 UN271 is currently the record-holder for big comets. And, it may be just the tip of the iceberg. There could be many more monsters out there for astronomers to identify as sky surveys improve in sensitivity. Though astronomers know this comet must be big to be detected so far out to a distance of over 2 billion miles from Earth, only the Hubble Space Telescope has the sharpness and sensitivity to make a definitive estimate of nucleus size. Credits:
Illustration: NASA, ESA, Zena Levy (STScI) by Kat Troche of the Astronomical Society of the Pacific
If you spotted comet C/2023 A3 (Tsuchinshan-ATLAS) in person, or seen photos online this October, you might have been inspired to learn more about these visitors from the outer Solar System. Get ready for the next comet and find out how comets are connected to some of our favorite annual astronomy events.
Comet Composition
A comet is defined as an icy body that is small in size and can develop a ‘tail’ of gas as it approaches the Sun from the outer Solar System. The key traits of a comet are its nucleus, coma, and tail.
The nucleus of the comet is comprised of ice, gas, dust, and rock. This central structure can be up to 80 miles wide in some instances, as recorded by the Hubble Space Telescope in 2022 – large for a comet but too small to see with a telescope. As the comet reaches the inner Solar System, the ice from the nucleus starts to vaporize, converting into gas. The gas cloud that forms around the comet as it approaches the Sun is called the coma. This helps give the comet its glow. But beware: much like Icarus, sometimes these bodies don’t survive their journey around the Sun and can fall apart the closer it gets.
The most prominent feature is the tail of the comet. Under moderately dark skies, the brightest comets show a dust tail, pointed away from the Sun. When photographing comets, you can sometimes resolve the second tail, made of ionized gases that have been electronically charged by solar radiation. These ion tails can appear bluish, in comparison to the white color of the dust tail. The ion tail is also always pointed away from the Sun. In 2007, NASA’s STEREO mission captured images of C/2006 P1 McNaught and its dust tail, stretching over 100 million miles. Studies of those images revealed that solar wind influenced both the ion and dust tail, creating striations – bands – giving both tails a feather appearance in the night sky.
Comet McNaught over the Pacific Ocean. Image taken from Paranal Observatory in January 2007. Credits: ESO/Sebastian Deiries Coming and Going
Comets appear from beyond Uranus, in the Kuiper Belt, and may even come from as far as the Oort Cloud. These visitors can be short-period comets like Halley’s Comet, returning every 76 years. This may seem long to us, but long-period comets like Comet Hale-Bopp, observed from 1996-1997 won’t return to the inner Solar System until the year 4385. Other types include non-periodic comets like NEOWISE, which only pass through our Solar System once.
But our experiences of these comets are not limited to the occasional fluffy snowball. As comets orbit the Sun, they can leave a trail of rocky debris in its orbital path. When Earth finds itself passing through one of these debris fields, we experience meteor showers! The most well-known of these is the Perseid meteor shower, caused by Comet 109P/Swift-Tuttle. While this meteor shower happens every August in the northern hemisphere, we won’t see Comet Swift-Tuttle again until the year 2126.
The Perseids Meteor Shower. NASA/Preston Dyches See how many comets (and asteroids!) have been discovered on NASA’s Comets page, learn how you can cook up a comet, and check out our mid-month article where we’ll provide tips on how to take astrophotos with your smartphone!
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By USH
Over the years, numerous mysterious events have been witnessed in the sky, defying explanation. Recently, yet another unusual sky phenomenon was observed over Southern Australia capturing attention and sparking curiosity.
Video footage reveals what appears to be a dome-shaped structure, with an even stranger detail: lightning seems to bounce off or perhaps even originate from within the dome.
The mysterious formation has led to numerous theories. Some viewers suggest it could be a unique (red) rainbow or a rare weather event like a haboob (sandstorm). Others speculate it might be the result of weather manipulation or even an energy field projected over the region.
Opinions also vary on the lightning, some say it’s bouncing off the dome, while others believe it could be emanating from within. Although it may just be an unusual natural phenomenon, the seemly strange interaction with the lightning remains unexplained.
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