Question: What are the rocks from Mars made from, what materials do they contain and are there any specific particles found on the rocks that are found nowhere else;have you found any micro organisms or signs of life on the rocks that you are studying , also what is the texture of the rocks and do the erode after a while?

Jane MacArthur answered on 11 Nov 2014:

Wow, 7 questions in 1, and all good ones! Fundamentally, rocks on Mars are made from the elements we already know to exist on Earth, the main ones being oxygen, silicon, aluminium, iron, calcium, sodium, potassium, magnesium. Combinations of these make different minerals which also exist on Earth, such as quartz, olivine, feldspar, pyroxenes, etc.

I haven’t found any micro organisms or signs of life in the rocks I am studying. As meteorites are found on Earth and may have been lying there for 100s or 1000s of years, it is hard to distinguish weathering and features that may have happened on Earth to those which may have happened on Mars. This will always be a problem if anyone does find a possible sign of life in a meteorite and it would be hard to definitely prove it happened on Mars. This is why we’d like a sample return mission, which can obtain a sample from a known location on Mars, and return it to Earth with no contamination.

Meteorites hit the Earth all the time and the vast majority are never known or identified as they fall into the oceans or into forest/developed land where they are quickly eroded and weathered. The best locations for finding meteorites are in deserts (little wind, rain so little erosion) and Antarctica – NASA lead a special expedition called ANSMET (Antarctic Search for Meteorites) for 6 weeks every Antarctic summer, where usually a few hundred pristine meteorites can be found. A couple of years ago two of them turned out to be from Mars!