Posted on 03/15/2007 2:14:24 PM PDT by blam
Did a giant impact create the two faces of Mars?
16:29 15 March 2007
NewScientist.com news service
David Shiga, Houston
Mars's northern hemisphere is lower in elevation – by about 5 kilometres – than its southern hemisphere (see image below). This coloured topographical map shows low elevations in blue and high elevations in yellow and red. The map is centred on a latitude of 55° north (Illustration: Mike Caplinger/MSSS)
Mars's southern hemisphere is higher and more heavily cratered than the northern hemisphere, suggesting it is older terrain. The two low elevations (blue) in this map, which is centred on the southern mid-latitudes, are the impact basins Argyre and Hellas (Illustration: Mike Caplinger/MSSS) The impact of a giant asteroid could explain why Mars has two very different faces – but only if it struck the planet with a glancing blow, computer simulations suggest.
A longstanding puzzle about Mars is why its northern and southern hemispheres are so different. The northern hemisphere is much flatter and lies lower than the southern hemisphere, with a difference in elevation between the two of about 5 kilometres.
In the 1980s, scientists suggested a giant impact by an asteroid about 300 kilometres across in Mars's early history could have led to a permanent depression in the planet's northern hemisphere.
Now, two teams of scientists have created the first computer simulations testing whether such an impact could have produced the observed differences.
Shawn Hart of the University of California in Santa Cruz, US, led one of the simulation teams. His team found that such an impactor would produce huge amounts of lava – enough to cover the planet in an ocean of molten rock somewhere between 14 and 48 kilometres thick. That would have ended up erasing any record that an impact happened
(Excerpt) Read more at space.newscientist.com ...
http://webster.aip.org/enews/physnews/1999/split/pnu432-3.htm
Physics News Update
The American Institute of Physics Bulletin of Physics News
Number 432 (Story #3), June 7, 1999 by Phillip F. Schewe and Ben Stein
THE SURFACE OF MARS has been mapped to 13-meter precision, better than for some places on Earth. Laser light sent from and returning to the orbiting Mars Global Surveyor spacecraft reveals that the southern hemisphere is one big highland (6 km higher) compared to the northern hemisphere. Surface water, if there was any, would have collected in the North, although there is not yet definitive proof of any boreal ocean. One thing that is known about the northern lowland: it is the flattest place in the solar system. The South's elevation is due at least in part to an immense amount of material raised during an ancient impact which fashioned a huge crater known as the Hellas basin. (Science, 28 May 1999.)
The main difference between the two shots is that in the earlier shot, "The Face" is made up of about three dozen pixels. The Face on Mars is indeed an artifact, but it is merely the artifact of the Viking orbiter camera resolution.
But nothing about cosmic collisions.
Heh... the atmosphere's too thin to carve, but apparently just thick enough (similar to Earth's at 40 miles altitude -- Everest is about six miles) to support a civilization. ;')
Excellent point. But, that was then, and this is now, and after the Martians built "the face", they migrated to Earth because Mars' atmosphere was being blown away by global warming caused by Martian activity.
:') That's precisely my point -- if the atmosphere has thinned out and destroyed the supposed civilization, how can Hoaxland claim that it was previously "too thin to carve"? As is generally the case, he's full of it.
And he has a sense of humor too.
However, as a taxpayer, I'm insulted that he wants NASA to drop everything to chase after his personal white whales.
I sometimes think he's a NASA plant to hype it's funding requests to they can hire even more astronauts to go crazy sitting around doing nothing for a decade or more.
:')
Here's a Catastrophism ping list topic. This one shows up at the top, but is the last of the ones I've pinged you two to. :')
http://nssdc.gsfc.nasa.gov/planetary/mgs_cydonia.html
That image shows straight lines and Bezier curves on a three-mile scale; Ma Nature don't do stuff like that.
Most interesting new photo from the neighborhood of Mars is the HIRISE image of Phobos:
In fact if you do a google search on just "phobos", that image is now the first item that turns up. That's right, real moons are supposed to be made out of dirt and green cheese and stuff like that which doesn't reflect light all over the place and can't be formed into planks like that. As Hoagland says, you can almost count the rivets.
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