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.
Truth to tell, I don't remember the worm. I remember the red man, the green man, the white man, the yellow man and the black man. Oh yes, and the nasty plant eaters in the valley of Dor.
But I can't remember if all of the aforementioned were distinct types from the tree of life, or if some of them were hybrids.
I relate this to the iron meteors that people find out in the Mojave desert, usually on the surface rather than in the middle of an impact crater. Sometimes objects bounce, sometimes they sit around for a few thousand years as the sand around it shifts.
That is an amazing picture - so clear.
From "The Gods of Mars":
"The First Born of Barsoom," he explained, "are the race of black men of which I am a Dator, or, as the lesser Barsoomians would say, Prince. My race is the oldest on the planet. We trace our lineage, unbroken, direct to the Tree of Life which flourished in the centre of the Valley Dor twenty-three million years ago.
"For countless ages the fruit of this tree underwent the gradual changes of evolution, passing by degrees from true plant life to a combination of plant and animal. In the first stages the fruit of the tree possessed only the power of independent muscular action, while the stem remained attached to the parent plant; later a brain developed in the fruit, so that hanging there by their long stems they thought and moved as individuals.
"Then, with the development of perceptions came a comparison of them; judgments were reached and compared, and thus reason and the power to reason were born upon Barsoom.
"Ages passed. Many forms of life came and went upon the Tree of Life, but still all were attached to the parent plant by stems of varying lengths. At length the fruit tree consisted in tiny plant men, such as we now see reproduced in such huge dimensions in the Valley Dor, but still hanging to the limbs and branches of the tree by the stems which grew from the tops of their heads.
"The buds from which the plant men blossomed resembled large nuts about a foot in diameter, divided by double partition walls into four sections. In one section grew the plant man, in another a sixteen-legged worm, in the third the progenitor of the white ape and in the fourth the primaeval black man of Barsoom.
"When the bud burst the plant man remained dangling at the end of his stem, but the three other sections fell to the ground, where the efforts of their imprisoned occupants to escape sent them hopping about in all directions.
"Thus as time went on, all Barsoom was covered with these imprisoned creatures. For countless ages they lived their long lives within their hard shells, hopping and skipping about the broad planet; falling into rivers, lakes, and seas, to be still further spread about the surface of the new world.
"Countless billions died before the first black man broke through his prison walls into the light of day. Prompted by curiosity, he broke open other shells and the peopling of Barsoom commenced.
"The pure strain of the blood of this first black man has remained untainted by admixture with other creatures in the race of which I am a member; but from the sixteen-legged worm, the first ape and renegade black man has sprung every other form of animal life upon Barsoom.
Of course, this is only aa theory (obligaory sticker).
Well, yeah, but where did the plant men come from mentioned in the "God's of Mars?" Obviously they are original descendents of the Tree of Life, but there was only one Tree of Life, and that died Eons ago.
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Whoa Nelly!
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