David L. Chandler asks,
Are we all Martians? According to many planetary scientists, it’s conceivable that all life on Earth is descended from organisms that originated on Mars and were carried here aboard meteorites. If that’s the case, an instrument being developed by researchers at MIT and Harvard could provide the clinching evidence.- “Are you a Martian? We all could be, scientists say — and new instrument might provide proof” (Physorg March 23, 2011)
The article provides a useful summary of the state of the evidence, capped by
Christopher McKay, an astrobiologist at NASA-Ames Research Center in California who specializes in research related to the possibility of life on Mars, says this work is “very interesting and important.” He says, “it is not implausible that life on Mars will be related to life on Earth and therefore share a common genetics. In any case it would be important to test this hypothesis.”
Parts of the project I don’t get: The idea seems to be to search for sequences of DNA and RNA molecules that are “nearly universal in all forms of terrestrial life.”
Okay, but isn’t (almost) universal common descent the accepted explanation for that? Why drag Mars into it?
The researchers hope to find “living microbes” or their remains in Martian soil samples, and analyze them for the nearly universal code. Suppose they find some. Why should we suppose that we came from Mars rather than that the microbes came from Earth? The latter is vastly more plausible, I would say.
So far, it sounds like great sci-fi TV, and it would be a shame to take Occam’s Razor to it, so we won’t.