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Martian Microbe Fossils, Not So Debunked Anymore
rubycodez writes "Three meteorites, including one that has been in a British museum for over a century, are going to be put under the electron microscope and ion microprobe by NASA. We're 'very, very close to proving there is or has been life [on Mars],' said David McKay, chief of astrobiology at Johnson Space Center."
Disclaimer: I am a planetary scientist but do not work directly on the martian meteorites.
1) We know that the rocks are from Mars because they all have consistent isotope ratios between the various meteorites that are inconsistent with those isotope ratios on Earth but consistent with isotopic ratios on Mars
http://wapedia.mobi/en/Neutron_activation_analysis
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6T-41WBDHD-8&_coverDate=10%2F31%2F2000&_alid=445411040&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5823&_sort=d&view=c&_acct=C000053194&_version=1&_urlVersion=0&_userid=1495569&md5=1c1b0d04dba7f06365b072655bef68b3 (May need a subscription)
2) The age(s) of the possible fossils are greater than the time the meteorites have been on Earth. Again, this can be calculated using various isotope ratios. In essence, these things formed while the rocks were still on Mars.
3) I agree with your discomfort with the word "prove." Most scientific study is based on the Popper philosophy of disproving something rather than proving its opposite.
A) The new instrumentation and techniques being used on these meteorites are greatly advancing our understanding of them. The press announcement that AH84001 might have evidence of life was premature (what we call "science by press release"), but the publications by the team were certainly good and valid work, whether they are falsified or not...
B) The scientific word "prove" is more about the lack of any valid competing hypotheses. If you can't come up with a reasonable alternative explanation for the data, you have to accept the presented explanation.