NASA Spacecraft Detects Impact Glass on Surface of Mars

NASA's Mars Reconnaissance Orbiter (MRO) has detected deposits of glass within impact craters on Mars. Though formed in the searing heat of a violent impact, such deposits might provide a delicate window into the possibility of past life on the Red Planet.
During the past few years, research has shown evidence about past life has been preserved in impact glass here on Earth. A 2014 study led by scientist Peter Schultz of Brown University in Providence, Rhode Island, found organic molecules and plant matter entombed in glass formed by an impact that occurred millions of years ago in Argentina. Schultz suggested that similar processes might preserve signs of life on Mars, if they were present at the time of an impact.
Fellow Brown researchers Kevin Cannon and Jack Mustard, building on the previous research, detail their data about Martian impact glass in a report now online in the journal Geology.
"The work done by Pete and others showed us that glasses are potentially important for preserving biosignatures," Cannon said. "Knowing that, we wanted to go look for them on Mars and that's what we did here. Before this paper, no one had been able to definitively detect them on the surface."
Cannon and Mustard showed large glass deposits are present in several ancient, yet well-preserved, craters on Mars. Picking out the glassy deposits was no easy task. To identify minerals and rock types remotely, scientists measured the spectra of light reflected off the planet's surface. But impact glass doesn't have a particularly strong spectral signal.
"Glasses tend to be spectrally bland or weakly expressive, so signature from the glass tends to be overwhelmed by the chunks of rock mixed in with it," said Mustard. "But Kevin found a way to tease that signal out."
In a laboratory, Cannon mixed together powders with a similar composition of Martian rocks and fired them in an oven to form glass. He then measured the spectral signal from that glass.
Once Mustard had the signal from the lab glass, he used an algorithm to pick out similar signals in data from MRO's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), for which he is the deputy principal investigator.
The technique pinpointed deposits in several Martian crater central peaks, the craggy mounds that often form in the center of a crater during a large impact. The fact the deposits were found on central peaks is a good indicator that they have an impact origin.
Knowing that impact glass can preserve ancient signs of life -- and now knowing that such deposits exist on the Martian surface today -- opens up a potential new strategy in the search for ancient Martian life.
"The researchers' analysis suggests glass deposits are relatively common impact features on Mars," said Jim Green, director of NASA's planetary science division at the agency's headquarters in Washington. "These areas could be targets for future exploration as our robotic scientific explorers pave the way on the journey to Mars with humans in the 2030s."
One of the craters containing glass, called Hargraves, is near the Nili Fossae trough, a 400-mile-long (about 650-kilometer-long) depression that stretches across the Martian surface. The region is one of the landing site contenders for NASA's Mars 2020 rover, a mission to cache soil and rock samples for possible return to Earth.
Nili Fossae trough is already of scientific interest because the crust in the region is thought to date back to when Mars was a much wetter planet. The region also is rife with what appear to be ancient hydrothermal fractures, warm vents that could have provided energy for life to thrive just beneath the surface.
"If you had an impact that dug in and sampled that subsurface environment, it's possible that some of it might be preserved in a glassy component," Mustard said. "That makes this a pretty compelling place to go look around, and possibly return a sample."
MRO has been examining Mars with CRISM and five other instruments since 2006.
"This significant new detection of impact glass illustrates how we can continue to learn from the ongoing observations by this long-lived mission," said Richard Zurek, MRO project scientist at NASA's Jet Propulsion Laboratory, Pasadena, California.

Fresh Crater on Mars Spied by NASA Spacecraft

A NASA Mars probe has photographed an impact crater that was blasted out of the Red Planet in just the last few years.

The HiRISE camera aboard NASA's Mars Reconnaissance Orbiter (MRO) captured the crater, which lies in the Red Planet's equatorial Elysium Planitia region, on Dec. 2, 2014. Scientists say the impact that gouged out the hole must have occurred between February 2012 and June 2014, based on previous images of the area.

The crater is about 40 feet (12 meters) wide, said HiRISE team member Ingrid Daubar of NASA's Jet Propulsion Laboratory in Pasadena, California.

"We've been finding new craters like this for a few years now, and from studying their frequency, we've come up with a cratering rate for Mars based on them," Daubar told Space.com via email.

"For craters this size (12 m diameter), we expect about 30 of these are forming over all of Mars each year," she added. "We only find a few of them, though, because we have to be looking in the right area. They're not as easy to find over non-dusty areas where they don't form these huge dark blast zones around the impact site."

The new photo is the first one HiRISE — short for High Resolution Imaging Science Experiment — has taken of the crater. The feature was actually discovered by MRO's Mars Context Camera, NASA officials said.

The objects that create Martian craters such as this one strike the surface at very high speeds — an average of 22,000 mph (35,400 km/h) — and are almost always completely destroyed in the process, Daubar said.

Indeed, there is no sign of the impactor in the new HiRISE photo. The silvery crescent toward the right side of the crater is just the illuminated interior wall of the crater, Daubar said. (In the image, sunlight is coming from the lower left.)

The $720 million MRO mission launched in August 2005 and arrived in orbit around Mars in March 2006. The spacecraft has been studying the Red Planet ever since with six scientific instruments. MRO also serves as a vital communications link between Earth and NASA's active Mars surface craft, the Opportunity and Curiosity rovers.

Researchers in remote East Antarctica think a massive area of fractured ice discovered last month could be a newfound meteorite impact crater.

The mile-wide crater (about 2 kilometers across) is a circular scar marked by fractured, rumpled ice — a striking blot in this otherwise smooth section of Antarctica's King Baudouin Ice Shelf. It was spotted by German scientist Christian Müller during an aerial survey by plane on Dec. 20, 2014.

"I looked out of the window, and I saw an unusual structure on the surface of the ice," Müller said in a video describing the discovery. "There was some broken ice looking like icebergs, which is very unusual on a normally flat ice shelf, surrounded by a large, wing-shaped, circular structure," said Müller, a geoscientist with Fielax, a private company assisting Antarctic research.

Lucky find

The possible impact crater is about twice the size of Arizona's Barringer Meteor Crater. Satellite images suggest the broken-up ice could be at least 25 years old.

The crater was a serendipitous find, sighted by chance north of Belgium's Princess Elisabeth Research Station. German researchers at the station intended to remotely survey the surrounding bedrock, in order to gather new details on the Gondwana supercontinent's formation and breakup between 550 million and 180 million years ago. Flying over busted-up ice shelves — the floating extensions of the Antarctic Ice Sheet — was not part of the research plan.

"We were only flying that far in the north because the radar equipment had broken, and we didn't want to waste a good flying day," said Graeme Eagles, a scientist at Germany's Alfred Wegener Institute who is currently leading the geophysical research survey. "It's been a tremendously exciting couple of weeks," he added. "It really is a very raw form of science, with a lot of people speculating on what might or might not be the cause."
Antarctic researchers

At first, Müller connected the crater to a 2004 meteor blast detected above this part of East Antarctica. Recently, however, the German research team discovered the crater in satellite images dating back to 1996, Eagles said. "The [connection] to the 2004 event really piqued our interest in the first place, but I don't think what we've seen in the satellite images rules out the possibility of an impact origin," Eagles told Live Science. "It just fuzzies the story a little bit."

Extraordinary claims

If a space rock did crash-land on the ice shelf, the meteorite was likely relatively large. Indeed, the crater's sheer size warrants skepticism, experts said. [Crash! 10 Biggest Impact Craters on Earth]

As a rule of thumb, an object that formed a crater is usually about 10 to 20 times smaller than the crater itself, said Peter Brown, director of the Center for Planetary Science and Exploration at the University of Western Ontario in Canada. That means a 1.2-mile (2 km) crater would result from an object that measures roughly 325 feet (100 meters) across, Brown said.

"A very large explosion would have caused a 2-kilometer-wide crater — much larger than anything detected impacting Earth in recent history," Brown said. "So the feature seen is almost certainly not due to any meteorite impact."

Meteorite hunter Peter Jenniskens also found the crater idea implausible. "I don't think this is an impact crater," said Jenniskens, who holds dual affiliations at the SETI Institute and at NASA's Ames Research Center, both in California.

However, Eagles hinted that the German researchers have not shown all their cards. The scientists collected photos, video and data on a Dec. 26 trip to the crater site. The team mapped the ice surface in great detail with a laser-scanning instrument that records precise changes in topography. They also surveyed the area with a radar instrument that penetrates the upper surface of the ice and snow. A number of smaller circular and subcircular structures were spotted nearby on this trip. The researchers haven't yet analyzed the data, but they hope to publish their results in a scientific journal if the structure is indeed an impact crater, Eagles said.

"This thing is very unusual indeed," Eagles said. "Extraordinary claims require extraordinary evidence, and in this case, as far as we can tell, is does look like it is extraordinary evidence."

Rock hunters

The researchers now must complete their Gondwana study before squeezing in any more trips to the crater, Eagles said. For instance, the team would like to eventually hunt for meteorites around the site.

Antarctica's cold, dry conditions preserve meteorites that weather away on other continents, and more than 20,000 space rocks have been discovered in targeted searches on the frozen surface.

While scientists do come to Antarctica specifically to hunt for meteorites, finding a potential impact crater was an unexpected thrill for everyone at the research station, the researchers said. "There are new and exciting things to be discovered at any moment, anytime, in Antarctica, and you don't have to send probes to land on comets to make people's eyes sparkle," Eagles said.

Fresh Crater on Mars Spied by NASA Spacecraft (Photo)

This Mars Reconnaissance Orbiter image shows a new impact crater in Elysium Planitia that formed between February 2012 and June 2014.

A NASA Mars probe has photographed an impact crater that was blasted out of the Red Planet in just the last few years.

The HiRISE camera aboard NASA's Mars Reconnaissance Orbiter (MRO) captured the crater, which lies in the Red Planet's equatorial Elysium Planitia region, on Dec. 2, 2014. Scientists say the impact that gouged out the hole must have occurred between February 2012 and June 2014, based on previous images of the area.

The crater is about 40 feet (12 meters) wide, said HiRISE team member Ingrid Daubar of NASA's Jet Propulsion Laboratory in Pasadena, California.
"We've been finding new craters like this for a few years now, and from studying their frequency, we've come up with a cratering rate for Mars based on them," Daubar told Space.com via email.

"For craters this size (12 m diameter), we expect about 30 of these are forming over all of Mars each year," she added. "We only find a few of them, though, because we have to be looking in the right area. They're not as easy to find over non-dusty areas where they don't form these huge dark blast zones around the impact site."

The new photo is the first one HiRISE — short for High Resolution Imaging Science Experiment — has taken of the crater. The feature was actually discovered by MRO's Mars Context Camera, NASA officials said.

The objects that create Martian craters such as this one strike the surface at very high speeds — an average of 22,000 mph (35,400 km/h) — and are almost always completely destroyed in the process, Daubar said.

Indeed, there is no sign of the impactor in the new HiRISE photo. The silvery crescent toward the right side of the crater is just the illuminated interior wall of the crater, Daubar said. (In the image, sunlight is coming from the lower left.)

The $720 million MRO mission launched in August 2005 and arrived in orbit around Mars in March 2006. The spacecraft has been studying the Red Planet ever since with six scientific instruments. MRO also serves as a vital communications link between Earth and NASA's active Mars surface craft, the Opportunity and Curiosity rovers.

Violent Asteroid Collision Recreated with High-Speed Cannon (Video)

esta, the solar system's brightest asteroid, used to be round until it got pounded by another space rock. The collision not only carved out a huge crater and left Vesta somewhat flattened, but it also cracked opened deep rifts around the asteroid's equator, some of them wider than the Grand Canyon.

To understand how Vesta's belt of fractures formed, scientists tried to recreate this violent impact in a lab and watch it slow motion, by shooting beads at softball-sized spheres with a high-speed cannon.

Scientists recently got a close look at the craggy surface of Vesta, the second most massive body in the asteroid belt, thanks to NASA's Dawn probe. Between 2011 and 2012, the spacecraft orbited the 330-mile-wide (530 kilometers) protoplanet.

"Vesta got hammered," Peter Schultz, a professor of earth, environmental, and planetary sciences at Brown University in Rhode Island, said in a statement. "The whole interior was reverberating, and what we see on the surface is the manifestation of what happened in the interior."

To get a better idea of how that reverberation played out, Schultz and colleagues turned to a massive cannon at the NASA's Ames Research Center in Moffett Field, California.

Dubbed the Ames Vertical Gun Range, the cannon has 14-foot (4.2 meters) barrel that's used to mimic celestial collisions, launching projectiles up to 16,000 mph (25,750 km/h) in vacuum chamber. For these experiments, Schultz's team shot tiny Pyrex beads at larger spheres that were about 4 inches (10 centimeters) in diameter and made of PMMA, a brittle, transparent acrylic material. PMMA is a good substitute for rock because it has mechanical properties similar to that of Earth's upper crust and it becomes opaque under stress, which allows researchers to track the damage.
Images taken with superfast cameras that capture a million shots per second show that the damage starts at the impact point. But then cracks start to form in the sphere's interior, opposite the impact point, the researchers said. These cracks extend to the sphere's center and grow outward toward the sphere's surface, in a pattern that looks like a blooming "rosette," according to the study. The edges of these "petals" are responsible for Vesta's deep canyons.

The experiments also shed light on the orientation of those canyons, which circle Vesta like a belt.

"The belt is askew, as if Vesta were making a fashion statement," Schultz said. That flashy placement suggests the impact object struck at an angle less than 40 degrees, at about 11,000 mph (17,700 km/h).

"Vesta was lucky," Schultz added. "If this collision had been straight on, there would have been one less large asteroid and only a family of fragments left behind."

The study was led Angela Stickle, a former graduate student at Brown, who is now a researcher at the Johns Hopkins University Applied Physics Laboratory. The results have already been published online and will appear in the February 2015 issue of the journal Icarus.