Meteorites

[etvisitor7]

Chunks of rock from the Martian surface occasionally collide with our planet. By 1997 twelve meteorites were positively identified as being from Mars. They are called SNC meteorites (named after the first 3 meteorites found: Shergotty, Nakhla and Chassingy). Dr. Colin Pillinger of the U.K. Planetary Sciences Research Institute says, "100 tons of Martian material arrive on Earth each year."
In 1984 Martian meteorite ALH84001 was discovered in Antarctica. In August 1996 NASA scientists identified tiny tubular structures in ALH84001 as being, "possible microscopic fossils of bacteria-like organisms that may have lived on Mars more than 3.6 billion years ago." In October 1996 British scientists announced that a 2nd meteorite from Mars, EETA 79001, contained the chemical signatures of life, in this case, "organisms that could have existed on Mars as recently as 600,000 years ago."

[DippyHippy]

The existence of Martian microbes on ALH84001 is still very much in dispute with leading experts arguing the case on both sides. However, from what I know, most scientists consider that the microbes - if they are microbes - did not originate from Mars.

[jimmy]

Does anyone know how the Martian rocks were propelled from the planet?

[Duane]

Yes Jimmy, the rocks were propelled away as a direct result of a meterite strike on the martian surface.

Take a look at this: http://www.lpl.arizona.edu/~jmelosh/HeadSNC.pdf


It's a bit academic, but gives a good explanation of the way ejecta from a strike can reach escape velocity.

[jce1975]

This article written just this week confirms the findings of microbes in that meteorite from 1996 ...

http://www.universetoday.com/am/publish/fu...ite.html?522004

After reading this article, it makes me wonder if life on earth, actually came from Mars? Could we all be descendents of Martians?

[VanderL]

Depends on whether the material from Mars arrived before or after life started, and Martians could very well be our descendents (surely these meteorites can be swapped both ways).
Cheers.

[Sp1ke]

Looking at it simplistically, I'd guess more meteorites would go from Mars to Earth since the former has lower gravity so it's easier for chunks of rock to escape; and more likely that Earth would catch them. (If course Earth would attract more objects in the first place to cause impacts - anyone for meteorite ping pong?)

[jimmy]

Thanks for the explanation and link Duane. Wow, that must be some impact!

[Duane]

I like that question VanderL. Another to consider is, could different mutations in bacteria which formed on the two planets have gone back & forth for a time? Maybe "decendants" is too strong a word!

[VanderL]

Well, let's first try to find out how those impacts happened, maybe we can match some of our Martian meteorites with the places on Mars where there is something missing. Like Valles Marineris, where there is a huge amount of material gone without any sediment to account for it. Strange, that there are 9 km deep canyons (that's seriously deep&#33 and no sediment where all that stuff should be transported to.
Cheers.

[DippyHippy]

Interesting article - and a discovery that was apparently overlooked by the mainstream media now we have Iraq to think about.

Does anyone think there's living bacteria on Mars right now?

[damienpaul]

I would not be surprised in the slightest Dips, I mean if bacteria can live in lakes under glaciers or in solid rock, i am sure it could easily proliferate everywhere

[Sp1ke]

I agree, Damien. If all sorts of animals can colonize remote Pacific islands, I don't see it as impossible for a similar thing on a planet - just much, much harder to do so limited to something small and hardy like bacteria.

[ToSeek]

Arctic, Antarctic, Mars

When scientists examined a meteorite from Mars under a microscope, they discovered tiny mineral spheres that, some argued, were produced by living organisms. Now, researchers working in the high Arctic have found similar mineral features, produced not by microbes, but by a volcano.