Echus Chasma From Mars Express

echus chasma. Credits: ESA/ DLR/ FU Berlin (G. Neukum)

 

Do these valleys on Mars come from gushes of water from past rainfall, or groundwater springs, or could they have possibly been formed from magma flows on Mars surface? That’s the debate surrounding the many valleys, chasms and dry gullies found on the Red Planet.

The majority of planetary geologists seem to favor the idea of water flowing on Mars surface in the past. The images shown here of Echus Chasma are from the European Space Agency’s Mar’s Express, and its High-Resolution Stereo Camera (HRSC). Echus Chasma is believed to be one of the largest water source regions on the Red Planet. The valleys, cut into the landscape look similar to drainage networks found on Earth.

The image here has a ground resolution of approximately 17 m/pixel, and is so clear and distinct it almost makes you feel like you’re there!

echus chasma.  Credits: ESA/ DLR/ FU Berlin (G. Neukum)
Image of the Echus Chasma showing elevation. Credits: ESA/ DLR/ FU Berlin (G. Neukum)

Echus Chasma is approximately 100 km long and 10 km wide. Echus Chasma is believed to be the water source region that formed Kasei Valles, a large valley which extends thousands of kilometers to the north. It’s located in the Lunae Planum high plateau, north of Valles Marineris – the Grand Canyon of Mars. This image indicates elevation data, also obtained by the HRSC.

Echus Chasma mosaic.  Credits: ESA/DLR/ FU Berlin (G. Neukum)
Echus Chasma mosaic. Credits: ESA/DLR/ FU Berlin (G. Neukum)

An impressive cliff, up to 4000 m high, is located in the eastern part of Echus Chasma. Possibly, gigantic water falls may once have plunged over these cliffs on to the valley floor. The remarkably smooth valley floor was later flooded by basaltic lava.

Echus Chasma. Credits: ESA/ DLR/ FU Berlin (G. Neukum)
Overhead view of the Echus Chasma. Credits: ESA/ DLR/ FU Berlin (G. Neukum)

The smaller valleys, also called sapping canyons, are believed to originate from the discharge of groundwater.

Original News Source: ESA

Where Do Meteorites Come From?

If you’ve ever held a real meteorite in your hand, you probably wanted to know, “Where has this rock been in space and where did it come from?” Until now, no one has been able to definitively establish where the majority of meteorites found on Earth came from because of the changes that occur in meteorites after they are ejected from the asteroids they were originally part of. The most common type of meteorite found on Earth, about 75% of those identified, are chondrites, stony bits of space rocks that didn’t undergo any melting while out in space. Two astronomers say have determined that most of these meteorites come from the asteroid belt between Mars and Jupiter. Using the GEMINI telescope, they found that asteroids in that region are similar to chondrites found on Earth.

This discovery is the first observational match between the most common meteorites and asteroids in the main belt. It also confirms the role of space weathering in altering asteroid surfaces.

To find the parent asteroid of a meteorite, the astronomers compared the spectra of a meteorite specimen to those of asteroids. This is a difficult task because meteorites and their parent asteroids underwent different processes after the meteorite was ejected. In particular, surfaces of asteroids are known to be altered by a process called “space weathering”, which is probably caused by micrometeorite and solar wind action that changes the surface and spectra of asteroid surfaces.

Meteoroids are created, usually when there is a collision between asteroids. When an impact of a large asteroid occurs, the fragments broken off can follow the same orbit as the primary asteroid. These groups of fragments are called “asteroid families.” Until recently, most of the known asteroid families have been very old (they were formed 100 million to billions of years ago), and younger families are more difficult to detect because asteroid fragments are closer to each other.

In 2006, four new, extremely young asteroid families were identified, with an age ranging from 50,000 to 600,000 years. The astronomers, Thais Mothé-Diniz from Brazil and David Nesvorný from the US observed these asteroids, obtaining visible spectra. They compared the asteroids spectra to the spectra of an ordinary chondrite (the Fayetteville meteorite, shown in the top photo) and found they matched.

Identifying the parent asteroid of a meteorite is a unique tool when studying the history of our solar system because one can infer both the time of geological events (from the meteorite that can be analyzed through dating techniques) and their location in the solar system (from the location of the parent asteroid).

Meteorites are also a major tool for knowing the history of the solar system because their composition is a record of past geologic processes that occurred while they were still incorporated in the parent asteroid.

Original News Source: Astronomy and Astrophysics

Spacewalk Retrieves Explosive Bolt

Two cosmonauts at the International Space Station conducted a spacewalk on Thursday and performed the delicate operation of removing an explosive bolt from the Soyuz capsule attached to the station. Ten explosive bolts in all on the Soyuz break the connections between the spacecraft’s crew capsule and its propulsion module during descent back to Earth. Engineers suspect one bad bolt delayed the compartment’s jettison during landings in October 2007 and April 2008, leading to steep, high-G descents, causing the capsule to land off-course and hit the ground harder than it should. Sergei Volkov and Oleg Kononenko removed the bolt located in the same spot as the ones diagnosed as being faulty on the other capsules. They placed it inside a blast-proof canister, which will be returned home aboard the Soyuz when the crew completes its mission in October.

The spacewalk took 6 hours and 18 minutes to complete. US astronaut Greg Chamitoff remained in the Soyuz during the spacewalk, part of the contingency plan for the unlikely event the Pirs airlock could not be repressurized. Otherwise he would not have had access to the station’s lifeboat through a depressurized Pirs. “We do not like to separate the crew from (the) escape vehicle,” flight director Bob Dempsey told reporters in a briefing last week. “Therefore Greg will be staying in there. He will have some laptops, books and computers to work on while he’s there.”

Although engineers assured the bolt would not denoted, Russian mission control repeatedly told the cosmonauts to go slow and take their time. About halfway into the spacewalk, the bolt had been removed and placed in the container. “Good! Thank God, it is in,” one cosmonaut exclaimed. Mission control then told the cosmonauts to take a five minute break “without any motions, without moving,” before moving on to complete their tasks.

Chamitoff will have another stay in the Soyuz next Tuesday, as Volkov and Kononenko will conduct another spacewalk on July 15 to outfit the Russian segment’s exterior, install one scientific experiment and retrieve another.

News Sources: NASA, NASA TV

Phoenix Lander Tries Out Soil Probe and Atomic Microscope

It’s not that the Phoenix lander’s mission to Mars is over – not by a longshot. But Phoenix did stick a fork in it. The “fork” is a four-pronged thermal and electrical conductivity probe that Phoenix poked into the Martian soil for the first time. The probe tool can help the science team assess how easily heat and electricity move through the soil from one spike to another. These measurements can provide information about frozen or unfrozen water in the soil. The probe is mounted on the “knuckle” of Phoenix’s Robotic Arm. The probe has already been used for assessing water vapor in the atmosphere when it is held above the ground.

The image above is a series of six images, taken on July 8, 2008, during the Phoenix mission’s 43rd Martian day, or sol, since landing. The insertion visible from the shadows cast on the ground on that sol was a validation test of the procedure. The spikes on the probe are about 1.5 centimeters or half an inch long.

Phoenix also tried out another instrument: atomic force microscope. This Swiss-made microscope builds an image of the surface of a particle by sensing it with a sharp tip at the end of a spring, all micro- fabricated from a sliver of silicon. The sensor rides up and down following the contour of the surface, providing information about the target’s shape.

“The same day we first touched a target with the thermal and electrical conductivity probe, we first touched another target with a needle about threeorders of magnitude smaller — one of the tips of our atomic force microscope,”said Michael Hecht of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., lead
scientist for the suite of instruments on Phoenix that includes both the conductivity probe and the microscopy station.

The atomic force microscope can provide details of soil-particle shapes as small as about 100 nanometers, less than one-hundredth the width of a human hair. This is about 20 times smaller than what can be resolved with Phoenix’s opticalmicroscope, which has provided much higher-magnification imaging than anythingseen on Mars previously.

The team for the robotic arm is still working out the best way to get samples of ice from the trench dug earlier called “Snow White,” and be able to transfer the samples quickly into the Thermal and Evolved-Gas Analyzer (TEGA) which heats samples and identifies vapors from them.

Scientists have yet to release any information about the second test from the Wet Chemistry Lab. They are still analyzing the results.

Original News Source: NASA’s Phoenix site

Nano-materials Could Protect Spacecraft and Satellites From Debris

Space junk in Earth orbit is becoming a big problem (here’s an previous UT article that illustrates the problem.) If the International Space Station or an operating communications or science satellite were struck by debris such as an old satellite, launch vehicle parts, or even something as small as a paint chip, it could mean disaster. Space debris also threatens the lives of astronauts and the launch of new satellites today, says Dr. Noam Eliaz, Head of the Biomaterials and Corrosion Laboratory at the School of Mechanical Engineering at Tel Aviv University. An expert in materials science and engineering, Dr. Eliaz is working to create and test new nano-materials and polymers to protect satellites and astronauts alike.

Eliaz is developing nano-based materials with special mechanical properties, such as high strength and wear resistance, and controllable electrical and thermal properties. “This could lead to a superior material for the external blankets of spacecraft,” says Eliaz. Some of the materials Eliaz has researched are being used by biomedical device companies and by aircraft industries worldwide.

One candidate Eliaz and his colleagues have investigated is a hybrid nano-material which incorporates small silicon-containing cages that can open and react with atomic oxygen to prevent further polymer degradation. Basically, a silicon skin would form to “patch” a puncture caused by a debris hit.

The team has also conducted space durability studies on polymers developed by the U.S. Air Force and Hybrid Plastics Inc, and the results are being reviewed by NASA and the European Space Agency (ESA). “Our simulation studies were done on Earth to determine how space debris will impact new polymers developed to protect space vehicles,” says Dr. Eliaz.

Original News Source: American Friends of Tel Aviv University

Cruising the Cloud Tops of Venus With a Solar-Powered Airplane

With all the orbital missions at the various planets in our solar system, scientists have been able to glean an amazing amount of data to help us understand our neighboring worlds. But imagine a mission that could fly lower than orbital altitudes — actually flying in the atmosphere of another planet and closer to the surface — and imagine how much more detailed the data could be. This type of mission would be especially helpful on Venus, where the intense heat and crushing air pressure at the surface basically precludes the success of any type of lander mission. So, last year, when NASA formed a Science and Technology Definition Team (STDT) to study the concept of a flagship mission to Venus, waiting in the wings was Dr. Geoffrey Landis. For the past several years Landis and a group of scientists and engineers from NASA’s Glenn Research Center have been studying the concept of a solar-powered airplane at Venus. Landis says a small aircraft powered by solar energy could fly continuously in Venus’ atmosphere, and would be an ideal vehicle for gathering data on both the planet’s atmosphere and surface, with the ability to maneuver almost anywhere.

“There’s a lot of interest in Venus at the moment,” said Landis. “We’ve been looking at Mars quite a bit lately, and in some ways Mars is Earth’s twin, but in even more ways, Venus is Earth’s twin. So we learn a lot about Earth by studying Venus.”

A solar powered airplane has been a long-time interest for Landis. “I spent a lot of time in college building model airplanes, so the idea of flying an airplane on Venus sounded very interesting to me,” he said.

Since 2000, Landis and his team have been studying this concept, and Landis recently presented their findings to NASA’s STDT for Venus. “I’ve been trying to drum up enthusiasm for the things we’ve done,” he said. The main work the group has done so far has been focusing on the airplane itself, verifying that the concept is actually going to work.

“We’ve done a thorough design study to determine if there are any showstoppers,” said Landis. “We don’t think there are. We think it’s a very doable project.”

The airplane would have to fold up to fit inside a small aeroshell for a “Discovery” class scientific mission. After arriving at Venus the craft would deploy from the aeroshell, unfold and begin gliding through the atmosphere. With solar cells covering the entire surface, the airplane would fly strictly on solar power, not needing fuel. The team has come up with a foldable design that has a wingspan of 9 meters and a length of just under 7 meters.

Surprisingly, the density of Venus’ atmosphere shouldn’t be a problem for a solar airplane mission. “At the altitudes we’ll be flying, it would be like flying at moderate altitudes on Earth,” said Landis. “Venus is actually a very easy planet to fly on. Interestingly, the problem on Venus is the wind. It turns out it’s a very windy planet, and we would like to be able to keep our solar airplane flying underneath the sun, so we have to fly faster than the wind so we can stay in the sunlight. If we can do that we can basically fly forever.”

The craft would have to be capable of sustained flight at or above the wind speed, about 95 m/sec at the cloud-top level, 65 to 75 km above the surface. For exploration at lower altitudes, the aircraft could glide down for periods of several hours and then climb back to higher altitudes, allowing the cloud layers to be probed. But the airplane would have to be in sunlight for a majority of the time. The team’s analysis of a flight using battery storage shows that it wouldn’t work to keep the aircraft aloft on battery power during the passage across the night side of the planet.

As far as the science that can be gleaned from a solar-powered airplane at Venus, Landis’ team has primarily envisioned a mission to study Venus’ atmosphere. However, they’ve also looked at using it for a radar mission, and in particular if two airplanes could be used, one could be a transmitter and the other a receiver to do what’s called “bistatic radar” where you vary the angle between the transmission and the receiver to provide additional information about the planet. But mainly, an airplane flies much closer to the surface than an orbiting spacecraft, to gather greater detailed information about the planet.

The current focus of Landis’ team has been deciding what type of science could be done, and how it could best be achieved. “What we’ve been doing lately is just studying Venus and asking ourselves, what do we want to do,” said Landis. “Is an airplane the right thing? We’ve also been looking at airships. You can make a zeppelin fly at the planet Venus, which has both advantages and disadvantages over an airplane, so we’re asking ourselves, at what altitude in the clouds do we want to fly — above, below, or in the clouds — and what science we can do? The very hard part on Venus is flying low. It’s very easy to fly high, but the lower you could fly, the better the science you could accomplish. But flying low will be tricky.”

Interestingly enough, last year, students from Boston University also conducted a design study of a solar airplane at Venus, and they looked at the design that Landis’ team had come up with. The BU students also concluded such as mission was quite feasible. “They looked at the basic airplane design: Can you actually fly on Venus? We looked at things like, could you fold it up into the aeroshell, and how would it be deployed, etc.,” Landis said. “We found this second study to be a very useful sanity check for us, that an independent group of people looked at our ideas, and said that no, this isn’t out of the question.”

So, when could a solar-powered airplane mission be ready to fly over Venus? “It depends on how hard the mission you want to do is,” said Landis. “If you’re doing a simple solar airplane mission, we’ve shown that there aren’t any technology showstoppers in the airplane itself, so I think it’s something we could do in the near term, by the next decade. But the more difficult the mission you’re interested in, say if you’re interested in flying low or in the polar regions, places where it’s harder to fly, we’d have to back off and think about what the correct type of vehicle would be.”

This paper discusses more information about the Venus Solar Powered Airplane

Baby Boomer Galaxy Found

This galaxy, Zw II 96 (about 500 million light-years away) resembles the Baby Boom galaxy which lies about 12.3 billion light-years away and appears in images as only a smudge.

A group of telescopes got together recently to check out a little hanky-panky going on in a galaxy in a very remote part of the universe. The Hubble and Spitzer Space Telescopes, Japan’s Subaru Telescope, the James Clerk Maxwell and the Keck Telescopes, all on Mauna Kea in Hawaii, and the Very Large Array in New Mexico pooled their various optical, infrared, submillimeter and radio capabilities to see why a distant galaxy appears to be conceiving stars at a tremendously fast rate. This galaxy, which has now been dubbed the “Baby Boom” galaxy, is giving birth to about 4,000 stars per year. In comparison, our own Milky Way galaxy turns out an average of just 10 stars per year. These telescopes weren’t just playing the part of a Peeping Tom; astronomers want to find out more about this incredibly fertile galaxy.

“This galaxy is undergoing a major baby boom, producing most of its stars all at once,” said Peter Capak of NASA’s Spitzer Science Center at the California Institute of Technology, Pasadena. “If our human population was produced in a similar boom, then almost all of the people alive today would be the same age.”

The discovery goes against the most common theory of galaxy formation, the Hierarchical Model. According to the theory galaxies slowly bulk up their stars over time, and not in one big burst as “Baby Boom” appears to be doing.

The Baby Boom galaxy, which belongs to a class of galaxies called starbursts, is the new record holder for the brightest starburst galaxy in the very distant universe, with brightness being a measure of its extreme star-formation rate. It was discovered and characterized using a suite of telescopes operating at different wavelengths. NASA’s Hubble Space Telescope and Japan’s Subaru Telescope, atop Mauna Kea in Hawaii, first spotted the galaxy in visible-light images, where it appeared as an inconspicuous smudge due to is great distance.

It wasn’t until Spitzer and the James Clerk Maxwell Telescope, also on Mauna Kea in Hawaii, observed the galaxy at infrared and submillimeter wavelengths, respectively, that the galaxy stood out as the brightest of the bunch. This is because it has a huge number of youthful stars. When stars are born, they shine with a lot of ultraviolet light and produce a lot of dust. The dust absorbs the ultraviolet light but, like a car sitting in the sun, it warms up and re-emits light at infrared and submillimeter wavelengths, making the galaxy unusually bright to Spitzer and the James Clerk Maxwell Telescope.

To learn more about this galaxy’s unique youthful glow, Capak and his team followed up with a number of telescopes. They used optical measurements from Keck to determine the exact distance to the galaxy — a whopping12.3 billion light-years. That’s looking back to a time when the universe was 1.3 billion years old (the universe is approximately 13.7 billion years old today).

The astronomers made measurements at radio wavelengths with the National Science Foundation’s Very Large Array in New Mexico. Together with Spitzer and James Clerk Maxwell data, these observations allowed the astronomers to calculate a star-forming rate of about 1,000 to 4,000 stars per year. At that rate, the galaxy needs only 50 million years, not very long on cosmic timescales, to grow into a galaxy equivalent to the most massive ones we see today.

“Before now, we had only seen galaxies form stars like this in the teenaged universe, but this galaxy is forming when the universe was only a child,” said Capak. “The question now is whether the majority of the very most massive galaxies form very early in the universe like the Baby Boom galaxy, or whether this is an exceptional case. Answering this question will help us determine to what degree the Hierarchical Model of galaxy formation still holds true.”

“The incredible star-formation activity we have observed suggests that we may be witnessing, for the first time, the formation of one of the most massive elliptical galaxies in the universe,” said co-author Nick Scoville of Caltech.

Original News Source: JPL

How Old Am I? Star Cluster Perplexes Astronomers

Ever have one of those moments when you can’t remember how old you are? A group of astronomers may have felt they were having a “senior moment” when they couldn’t seem to figure out exactly the age of stars in the open star cluster NGC 6791, located in the constellation Lyra. Conventional thinking among astronomers is that stars in open clusters form at the same time, but in this particular cluster, researchers found stars at three different ages: one group of white dwarf stars appeared to be 4 billion years old, a second group of white dwarfs seemed to 6 billion years old, while the other regular stars were calculated to be 8 billion years of age. The astronomers say this dilemma may fundamentally challenge the way astronomers estimate cluster ages. Ivan King of the University of Washington and leader of the group using the Hubble Space Telescope to study this star cluster said: “This finding means that there is something about white dwarf evolution that we don’t understand.”

I just love it when astronomers say something like that, because it means they’ll return to their telescopes and the data in order to figure out the dilemma, and we’ll learn something new. And that’s just what they did. At least, partially.

“The age discrepancy is a problem because stars in an open cluster should be the same age. They form at the same time within a large cloud of interstellar dust and gas. So we were really puzzled about what was going on,” explained astronomer Luigi Bedin, who works at the Space Telescope Science Institute in Baltimore, Md.

After extensive analysis, members of the research team realized how the two groups of white dwarfs can look different and yet have the same age. It is possible that the younger- looking group consists of the same type of stars, but the stars are paired off in binary-star systems, where two stars orbit each other. Because of the cluster’s great distance, astronomers see the paired stars as a brighter single star.

Their brightness made them look younger.

Binary systems are also a significant fraction of the normal stellar population in NGC 6791, which contains over 10,000 stars, and are also observed in many other clusters. However, this would be the first time they have been found in a white-dwarf population.

“Our demonstration that binaries are the cause of the anomaly is an elegant resolution of a seemingly inexplicable enigma,” said team member Giampaolo Piotto the University of Padova in Italy.

Bedin and his colleagues are relieved that they now have only two ages to reconcile: an 8- billion-year age of the normal stellar population and a 6-billion-year age for the white dwarfs. All they need now is a process that slows down white-dwarf evolution.

Hubble’s Advanced Camera for Surveys analyzed the cooling rate of the entire population of white dwarfs in NGC 6791, from brightest to dimmest. White dwarfs are the smoldering embers of Sun-like stars that no longer generate nuclear energy and have burned out. Their hot remaining cores radiate heat for billions of years as they slowly fade into darkness. Astronomers have used white dwarfs as a reliable measure of the ages of star clusters, because they are the relics of the first cluster stars that exhausted their nuclear fuel.

White dwarfs have long been considered dependable because they cool down at a predictable rate. The older the dwarf, the cooler it is, making it a seemingly perfect clock that has been ticking for almost as long as the cluster has existed.

All right, astronomers, back to your telescopes to get this all figured out! And when they do, the rest of you can read about it on Universe Today. In the meantime, enjoy the lovely images above of star cluster NGC 6791.

News Source: Hubble press release

One More Item Found in Astounding HiRise Image of Phoenix Descending

Remember the amazing image that the HiRISE Camera on the Mars Reconnaissance Orbiter captured of the Phoenix Lander as it descended to Mars’ surface via parachute back on May 25? Well, the HiRISE scientists have done a little more processing of the image, and have turned up an additional detail they didn’t see at first: Phoenix’s heat shield. The heat shield, which had been jettisons just after parachute deployment, can be seen falling toward the surface. You have to look really, really close to see it. But that’s what these HiRISE folks do. It was incredible that they found the lander with the parachute in the image (go see the big, huge image they had to hunt for it HERE) and these guys get the eagle eyes of the year award for finding the heat shield.

HiRISE made history by taking the first image of a spacecraft as it descended toward the surface of another planetary body. Here’s the image again:

The image shows NASA’s Phoenix Mars Lander when the spacecraft was still tucked inside its aeroshell, suspended from its parachute, at 4:36 p.m. Pacific Daylight Time on landing day. Although Phoenix appears to be descending into an impressive impact crater, it actually landed 20 kilometers, or 12 miles, away.

Mars Reconnaissance Orbiter was about 760 kilometers, or 475 miles, away when it pointed the HiRISE camera obliquely toward the descending Phoenix lander. The camera viewed through the hazy Martian atmosphere at an angle 26 degrees above the horizon when it took the image. The 10-meter, or 30-foot, wide parachute was fully inflated. Even the lines connecting the parachute and aeroshell are visible, appearing bright against the darker, but fully illuminated Martian surface.

In further analyzing the image, the HiRISE team discovered a small, dark dot located below the lander.
Phoenix was equipped with a heat shield that protected the lander from burning up when it entered Mars’ atmosphere and quickly decelerated because of friction. Phoenix discarded its heat shield after it deployed its parachute.

“Given the timing of the image and of the release of the heat shield, as well as the size and the darkness of the spot compared to any other dark spot in the vicinity, we conclude that HiRISE also captured Phoenix’s heat shield in freefall,” said HiRISE principal investigator Alfred McEwen.

The multigigabyte HiRISE image also includes a portion recorded by red, blue-green and infrared detectors, and scientists have processed that color part of the image.

HiRISE’s color bands missed the Phoenix spacecraft but do show frost or ice in the bowl of the relatively recent, 10-kilometer (6-mile) wide impact crater unofficially called “Heimdall.” The frost shows up as blue in the false-color HiRISE data, and is visible on the right wall within the crater.

The HiRISE camera doesn’t distinguish between carbon dioxide frost and water frost, but another instrument called CRISM on the Mars Reconnaissance Orbiter could.

News Source: SpaceRef

The Sunny Side of Asteroids

Asteroids with moons, called binary asteroids, are fairly common in the solar system. But scientists haven’t been able to figure out the dynamics of these asteroids, especially how the moons form. But a group of astronomers studying binary asteroids say the surprising answer is sunlight, which can increase or decrease the spin rate of an asteroid. The researchers also say that since there are a number of “double craters” on Earth – side-by side craters that appear to have formed at about the same time — these binary asteroids may have hit our planet in the past. The image above is of twin circular lakes in Quebec, Canada, formed by the impact of an asteroidal pair which slammed into the planet approximately 290 million years ago. Similar double craters also can be found on other planets, as well.

Derek Richardson, of the University of Maryland, and Kevin Walsh and Patrick Michel at the Cote d’Azur Observatory, France outline a model showing that when solar energy “spins up” a “rubble pile” asteroid to a sufficiently fast rate, material is slung off from around the asteroid’s equator. This process also exposes fresh material at the poles of the asteroid.

If the spun off bits of asteroid rubble shed sufficient excess motion through collisions with each other, then the material coalesces into a satellite that continues to orbit its parent.

Link to an animated model of the spin-up and binary formation from two views, on the left is an overhead view. The right pane of the movie looks at the equator of the primary body, which is also the plane in which the asteroid’s satellite is formed (courtesy of the authors of the study).

Because the team’s model closely matches observations from binary asteroids, it neatly fills in missing pieces to a solar system puzzle. And, it could have much more down-to-earth implications as well. The model gives information on the shapes and structure of near-Earth binary asteroids that could be vital should such a pair need to be deflected away from a collision course with Earth.
The authors say that their current findings also suggest that a space mission to a binary asteroid could bring back material that might shed new light on the solar system’s early history. The oldest material in an asteroid should lie underneath its surface, explained Richardson, and the process of spinning off this surface material from the primary asteroid body to form its moon, or secondary body, should uncover the deeper older material.

“Thus a mission to collect and return a sample from the primary body of such a binary asteroid could give us information about the older, more pristine material inside an asteroid,” Richardson said.

Original News Source: PhysOrg