Posted on 01/18/2005 6:25:44 PM PST by NormsRevenge
LOS ANGELES - In a stroke of luck, the NASA (news - web sites) rover Opportunity has discovered a basketball-size metal meteorite sitting on the surface of Mars, the mission's main scientist said Tuesday.
Opportunity came upon the meteorite last week while it was taking a look at a spacecraft shell that was jettisoned before landing after protecting the rover during its plunge through the martian atmosphere.
Tests performed during the weekend confirm it is a nickel-iron meteorite, said Steve Squyres, a Cornell University scientist who is the principal investigator for NASA's Mars Exploration Rovers mission.
"I didn't see this one coming," Squyres said. "I try very hard to anticipate the things that we might find and the things we might need to know, and be prepared for things, but an iron meteorite was not something that I was expecting."
Whether or not other meteorites are found may help scientists determine whether the martian surface is being covered by wind-blown materials or whether surface material is being stripped away, Squyres said.
Opportunity landed Jan. 24 on the Meridiani plains, halfway around the planet from where its twin, Spirit, set down in the Gusev Crater region on Jan. 3, 2004.
Opportunity, a six-wheeled robot geologist, quickly discovered rocks showing that its area of Meridiani was once soaked in water, the major scientific finding of the twin-rover mission. After that it explored rocks in a deep crater and then went to conduct an engineering study of its jettisoned heat shield. The meteorite was sitting nearby.
"I've actually told the team that we probably shouldn't linger here long because this is obviously the place at Meridiani Planum where large metal objects fall from the sky," Squyres joked.
The meteorite immediately appeared different from anything scientists had seen at either landing site.
"And then we looked at it with our infrared spectrometer and it looked like the martian sky, which is really weird," he said. The metal surface, he explained, was reflecting sky radiation instead of emitting much of its own.
During the weekend, the rover drove to the meteorite and deployed its instrument arm to confirm its origin.
The rover used its brush to remove dust but did not try to grind into the meteorite with its rock abrasion tool because of the outcome of a test conducted by the tool's maker, Honeybee Robotics of Manhattan.
"We contacted the meteorite department at the American Museum of Natural History in New York and they were generous enough to give us a piece of nickel-iron meteorite to try grinding into, and in like an hour of grinding we wore away about 25 percent of the grinding heads," Squyres said.
"We designed our rock abrasion tool for rock. We didn't design it for nickel-iron alloys."
Scientists are not interested in the meteorite itself. Rather, they want to see if other objects spotted out on the Meridiani plains are also meteorites and what that might tell them about Mars.
"You've got sort of a steady rain of meteorites on to the martian surface. It's at a very slow rate, but they are going to accumulate over time." Squyres said.
If sand is continually blowing in and being deposited on the surface, burying things and building up terrain over time, meteorites will be covered and few will be seen, he said. But if fine surface material is being continuously stripped away by the wind, coarse things like meteorites will be left behind and their accumulation will show.
"So whether you're seeing a net accumulation or a net burial of the meteorites is going to tell you something about what the erosion or deposition rates are out on the plains," he said.
Please read Post 23 and report back.
My money's on the tribbles.
got a question?
If mars has gravity... Less than earths but still has enough. Why isnt their an impact crater around this metiorite?
perhaps a "grazing shot"?
Mars has windstorms.
Humor?
er... why isnt it buried? the surface appears flat. If it hit it would have caused a divit no? Okay then sand filled in the divit/crater but didnt cover the metieor? Not sure I understand... someone please get out the hand puppets.
Sandstorms deposit sand. Sandstorms also remove sand. We got lucky in that we were in the neighborhood while the the sands were blown off.
It's a nerf-ball meteorite.
Sometimes my golf ball does that ...
SAK
Why do you think it would sink? I drove an SUV (weighing several thousand pounds) over some sand last week; it didn't sink. Sand may slide around, but it will support lots of weight.
The lack of a crater though could show (guess work on my part here) that the thing landed; was covered; then the sand blew away. The crate could be large or small depending on speed on arrival.
But the atmosphere machines seem to be running slowly now.
What did happen to the sixteen-legged worm?
Maybe it went underground to the home of the black pirates?
It was only mentioned as one of the four creatures from the Tree of Life. The others (I think) had some history, but not the worm.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.