Skip to comments.Almighty Smash Left Record Crater On Mars
Posted on 06/25/2008 1:29:46 PM PDT by blam
Almighty smash left record crater on Mars
25 June 2008
From New Scientist Print Edition.
A giant impact explains why Mars's two hemispheres are so different (Illustration: Jeff Andrews-Hanna)
Five minutes after Mars was hit by an asteroid travelling at 40 times the speed of sound, pieces of the planet's crust (orange blobs) are flung into space, while a shock wave propagates into the planet's molten core (yellow) (Illustration: Francis Nimmo)
A suspected crater in the planet's northern hemisphere forms a kidney shape (blue region at left), but when researchers studied the variations in the strength of gravity above the region, they found the crater was actually a near-perfect ellipse (right) that had been partially covered over by lava (Illustration: J Andrews-Hanna et al/Nature)
EVERY scar tells a story, yet a huge gash on Mars has long proven very hard to read. Now a peek beneath the planet's surface reveals that the scar is the largest known impact structure in the solar system - gouged out by a collision that reshaped the Red Planet.
The surface of Mars's northern hemisphere lies about 6 kilometres lower than that of the southern hemisphere. This has greatly influenced the planet's evolution, says Jeffrey Andrews-Hanna of the Massachusetts Institute of Technology.
The northern hemisphere's thinner crust means more magma has been able to push to the surface to fuel volcanism, and the difference in altitude meant that ancient outbursts of liquid water tended to flow from south to north.
It also means that atmospheric pressure on northern surfaces is higher than in the south, encouraging winds there to scour the surface more than in the opposite hemisphere. As a result, it seems likely that more dust has been blown from
(Excerpt) Read more at space.newscientist.com ...
Is that the asteroid that wiped out the dinosaurs?
Nah. That was the Chicxulub Meteor, 65 million years ago.
He meant the Martian dinosaurs, Blam.
No this is the asteroid that wiped out the Barsoomians
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Andrews-Hanna and co-authors Maria Zuber of MIT and Bruce Banerdt of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., report the new findings in the journal Nature this week. A giant northern basin that covers about 40 percent of Mars’ surface, sometimes called the Borealis basin, is the remains of a colossal impact early in the solar system’s formation, the new analysis suggests. At 5,300 miles across, it is about four times wider than the next-biggest impact basin known, the Hellas basin on southern Mars. An accompanying report calculates that the impacting object that produced the Borealis basin must have been about 1,200 miles across.
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“It’s a very old idea, but nobody had done the numerical calculations to see what would happen when a big asteroid hits Mars,” said Francis Nimmo, associate professor of Earth and planetary sciences at UCSC and first author of one of the papers.
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Phoenix Mars lander puts soil in chemistry lab
UNIVERSITY OF ARIZONA NEWS RELEASE
Posted: June 25, 2008
TUCSON, Ariz. — NASA’s Phoenix Mars Lander placed a sample of Martian soil in the spacecraft’s wet chemistry laboratory today for the first time. Results from that instrument, part of Phoenix’s Microscopy, Electrochemistry and Conductivity Analyzer, are expected to provide the first measurement of the acidity or alkalinity of the planet’s soil.
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:’) Just in case...