Skip to comments.Meteorite Impacts Expose Ice on Mars
Posted on 09/25/2009 10:41:29 AM PDT by Dallas59
"This ice is a relic of a more humid climate from perhaps just several thousand years ago," says Shane Byrne of the University of Arizona, Tucson.
Byrne is a member of the team operating the orbiter's High Resolution Imaging Science Experiment, or HiRISE camera, which captured the unprecedented images. Byrne and 17 co-authors report the findings in the Sept. 25 edition of the journal Science.
"We now know we can use new impact sites as places to look for ice in the shallow subsurface," adds Megan Kennedy of Malin Space Science Systems in San Diego, a co-author of the paper and member of the team operating the orbiter's Context Camera.
So far, the camera team has found bright ice exposed at five Martian sites with new craters that range in depth from approximately half a meter to 2.5 meters (1.5 feet to 8 feet). The craters did not exist in earlier images of the same sites. Bright patches darkened in the weeks following initial observations, as freshly exposed ice vaporized into the thin Martian atmosphere.
The finds indicate water-ice occurs beneath Mars' surface halfway between the north pole and the equator, a lower latitude than expected in the dry Martian climate.
During a typical week, the spacecraft's Context Camera returns more than 200 images of Mars that cover a total area greater than California. The camera team examines each image, sometimes finding dark spots that fresh, small craters make in terrain covered with dust. Checking earlier photos of the same areas can confirm a feature is new. In this way, the team has found more than 100 fresh impact sites.
see captionAn image from the camera on Aug. 10, 2008, showed apparent cratering that occurred after an image of the same ground was taken 67 days earlier. The opportunity to study such a fresh impact site prompted a look by the orbiter's higher resolution camera on Sept. 12, 2009, confirming a cluster of small craters.
Right: The patch of ice exposed at this late-2008 crater was large enough for the orbiter's spectrometers to take readings and confirm that it is H2O. [more]
"Something unusual jumped out," Byrne said. "We observed bright material at the bottoms of the craters with a very distinct color. It looked a lot like ice."
The bright material at that site did not cover enough area for a spectrometer instrument on the orbiter to determine its composition. "Was it really ice?" the team wondered. The answer came from another crater with a much larger area of bright material.
"We were excited [when we saw it], so we did a quick-turnaround observation," said co-author Kim Seelos of Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "Everyone thought it was water-ice, but it was important to get the spectrum for confirmation."
Mars Reconnaissance Orbiter Project Scientist Rich Zurek, of NASA's Jet Propulsion Laboratory, Pasadena, Calif., said, "This mission is designed to facilitate coordination and quick response by the science teams. That makes it possible to detect and understand rapidly changing features."
Thanks for this post. I hadn’t seen this.
Incredible. Thanks for posting this.
Possible the oceans are still there but covered with drifting dust?
Saw last night on the Science Channel that the water was extremely salty and welled up occasionally due to the interior of Mars still being hot. Of course we won’t really know until we get there...
That is what you';d expect. Our own oceans became salty at the time of the flood and the flood in all likelihood amounted to the oceans of Mars getting dumped onto this planet. That would also be the basic answer to the question of where Mars' former oceans went.
I can see the Elvis picture in the one on the left. I’m surprised that Hoagland fans haven’t turned up with intricate details of railroad yards and landing sites.
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