User:Robertinventor/meteorites from Mars possibilities (OR)

This is background research to help with the article User:Robertinventor/Concerns for an early Mars sample return backup which is now deleted, but may be useful in some way in the future for refs or to reuse the material.

At present it is OR but I expect that someone in the published research has gone through a similar line of argument. I haven't yet found any papers that present this entire argument so at present is OR and can't be included in the article.

Obviously when I find a source I will present the argument as it is in the source rather in the form presented here. Researching here as a way into the literature, and also helping with background understanding and material.

Re Zubrins argument (OR)
This is OR so can't go into the article and am trying to find any recent research into it post the NRC report. The ESF report doesn't discuss Mars meteorite transfer to Earth, just one sentence that (obviously) the possibility of Mars meteorite transfer means you can't reduce the probability to 0.

Anyway first, the Martian meteorites we have are nearly all igneous rocks. Many show sign of internal shock with internal spaces filled with a black glass, and are distinguished from lunar meteorites by being much more shock transformed. Curiously, there are almost no meteorites discovered yet that resemble any of the samples analysed on the surface. Just one that is a breccia.

http://www.imca.cc/mars/martian-meteorites.htm

Lots of links here. On cursory reading seems that a 100 km crater on Mars is needed to send large amounts of unshocked material to Earth. No idea how often those happen but seems like a starting point for deciding how long ago the meteorites we receive from Mars spent on their voyage to Earth. Perhaps also that can be measured directly by looking e.g. at effect of cosmic radiation on the meteorite?

http://users.tpg.com.au/users/tps-seti/swaprock.html

A couple of things from the NSF report - first - that they mention that no micro-organisms have yet been discovered in any of the Martian meteorites of non terrestrial origin. Of course that would be hard to prove that any micro-organism is from Mars but does mean that ideas of transfer from Mars via the meteorites are theoretical and not based on any evidence yet.

Ejection ages here: http://curator.jsc.nasa.gov/antmet/mmc/Chap%20I.pdf - interestingly, strongly clustered with similar rock types having similar ejection ages. With ages 1 million, 3 million, 4 million, 10 million, 15 millino and 20 million years approximately. Does look very like they come from a series of distinct impacts on Mars that occur every few million years. Seem also quite reasonable time periods for creation of 100 km radius impact craters on Mars.

The thing is - so far all this is OR and SYNTHESIS. Does any author make a similar point in a discussion of back contamination of Earth by Martian meteorites?

Here is what the NRC report says for reference:

The Significance of Martian Meteorites


 * Hmmm. So it says there have been no discernible effects, but there may have been effects. Well, if the effects are not discernible, I can live with them. Also, please get it through your head that there is no NSF report. Cheers, Warren Platts (talk) 21:58, 21 June 2013 (UTC)


 * Also, it's well known that bacteria can live in fractures within igneous rocks. And if they're not surface rocks, that's all the more reason to think they might harbor life, because as you well know, the thinking is that if there's life on Mars, it's most likely located well below the surface. So congratulations: you just strengthened Zubrin's argument... Warren Platts (talk) 22:01, 21 June 2013 (UTC)

http://www.lpi.usra.edu/meetings/metsoc2012/pdf/5271.pdf

- the authors present this as a reason for a MSR. But it does also work the other way around (OR of course) to serve as a reason for expecting that the meteorites on Earth are likley to be sterilized of life and not include much life from either present day sedimentary rocks or ancient life evidence, so may be a reason for believing that transfer of life from Mars to Earth is rare.