# meteorite from Mars? **URL:** \ **Category:** Factual Questions\ **Created:** [September 13, 2001, 5:11pm UTC](https://boards.straightdope.com/t/meteorite-from-mars/81376 "2001-09-13T17:11:29Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![justinh](https://avatars.discourse-cdn.com/v4/letter/j/9fc29f/32.png) [@justinh](https://boards.straightdope.com/u/justinh)\ **Post date:** [September 13, 2001, 5:11pm UTC](https://boards.straightdope.com/t/meteorite-from-mars/81376/1 "2001-09-13T17:11:29Z")
I have heard about the clues of life found on a meteorite from Mars. but how do they know it came from Mars. and how did it get knocked off Mars? ---
**Author:** ![Futile\_Gesture](https://avatars.discourse-cdn.com/v4/letter/f/f05b48/32.png) [@Futile\_Gesture](https://boards.straightdope.com/u/Futile_Gesture)\ **Post date:** [September 13, 2001, 5:24pm UTC](https://boards.straightdope.com/t/meteorite-from-mars/81376/2 "2001-09-13T17:24:29Z")
> [@](#): > > \*Originally posted by justinh \* > \*\*I have heard about the clues of life found on a meteorite from Mars. but how do they know it came from Mars. and how did it get knocked off Mars? \*\* Mineral composition of the rock would be identical to Mars. (not just chemically, but in particle formation, age, proportions, etc) It would have got knocked off by a **big** meteorite strike on Mars surface. ---
**Author:** ![The\_Great\_Gazoo](https://avatars.discourse-cdn.com/v4/letter/t/67e7ee/32.png) [@The\_Great\_Gazoo](https://boards.straightdope.com/u/The_Great_Gazoo)\ **Post date:** [September 13, 2001, 5:30pm UTC](https://boards.straightdope.com/t/meteorite-from-mars/81376/3 "2001-09-13T17:30:51Z")
> [@](#): > > \*Originally posted by justinh \* > \*\*I have heard about the clues of life found on a meteorite from Mars. but how do they know it came from Mars. and how did it get knocked off Mars? \*\* IANAM(Martian), but, a large asteroid or other large mass hitting Mars may drive some material into the atmosphere and it could reach escape velocity from Mars, thereby becoming a meteor. I believe they determine that it is from Mars by checking its composition - due to the inherent nature of Mars, there are certain patterns of radiation or actual amounts of different materials unique to Mars. (Hey! Wait a minute! I am a Martian! The Great Gazoo is from Mars!!! 😃 ) ---
**Author:** ![Podkayne](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Podkayne](https://boards.straightdope.com/u/Podkayne)\ **Post date:** [September 13, 2001, 5:39pm UTC](https://boards.straightdope.com/t/meteorite-from-mars/81376/4 "2001-09-13T17:39:44Z")
It is generally accepted that the structures found meteorite ALH 84001 could have been formed by non-biological processes, though not everyone agrees, and recently there’s been some more analysis that supports the assertion that some of these sturctures were formed by bacteria. Here’s a page on the many meteorites believed to have come from Mars, with links (many dead, sadly): [http://www.jpl.nasa.gov/snc/index.html](http://www.jpl.nasa.gov/snc/index.html) And here’s a very good page detailed page on ALH84001: [http://www.lpi.usra.edu/lpi/meteorites/life.html](http://www.lpi.usra.edu/lpi/meteorites/life.html) ---
**Author:** ![bup](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bup](https://boards.straightdope.com/u/bup)\ **Post date:** [September 13, 2001, 5:40pm UTC](https://boards.straightdope.com/t/meteorite-from-mars/81376/5 "2001-09-13T17:40:28Z")
I thought the consensus on that meteorite was that it was spewed (spewn?) out of a volcano when Mars was still geologically active. Oh, and at escape velocity, obviously. ---
**Author:** ![Podkayne](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Podkayne](https://boards.straightdope.com/u/Podkayne)\ **Post date:** [September 13, 2001, 6:13pm UTC](https://boards.straightdope.com/t/meteorite-from-mars/81376/6 "2001-09-13T18:13:22Z")
No, bup, that’s not a reasonable scenario. It was almost certainly thrown up by an impact, which can easily eject material, even from a large planet like Earth or Mars. ---
**Author:** ![justinh](https://avatars.discourse-cdn.com/v4/letter/j/9fc29f/32.png) [@justinh](https://boards.straightdope.com/u/justinh)\ **Post date:** [September 13, 2001, 7:03pm UTC](https://boards.straightdope.com/t/meteorite-from-mars/81376/7 "2001-09-13T19:03:51Z")
thanks a lot. the NASA site has all the scoop. never too old to learn. I always thought that the meteorites could have come from Mars, but they seem to have proven it.