Extra-terrestrial life found? Maybe.

A NASA researcher is claiming that he's found hard evidence of extra-terrestrial life, in the form of fossilized microbes on a meteorite:
Writing in the March edition of the Journal of Cosmology, Richard B. Hoover argues that an examination of a collection of 9 meteorites - called CI1 carbonaceous meteorites - contain "indigenous fossils" of bacterial life.
"The complex filaments found embedded in the CI1 carbonaceous meteorites represent the remains of indigenous microfossils of cyanobacteria, " according to Hoover. That matter-of-fact sentence also underscores the shout-out-loud implication that the detection of fossils of cyanobacteria in the CI1 meteorites raises the possibility of life on comets. And Hoover does not shy away from offering that very conclusion.
Well, not everyone is jumping on the bandwagon just yet. Phil Plait of Bad Astronomy writes,
Probably the biggest bump in the road for showing these things are life-forms is to show they are not the result of Earthly bacteria getting inside the meteorite after it hit. This is very tough to do, though Hoover says this in his paper:

Many of the filaments shown in the figures are clearly embedded in the meteorite rock matrix. Consequently, it is concluded that the Orgueil filaments cannot logically be interpreted as representing filamentous cyanobacteria that invaded the meteorite after its arrival. They are therefore interpreted as the indigenous remains of microfossils that were present in the meteorite rock matrix when the meteorite entered the Earth’s atmosphere.
Clearly, Hoover thinks terrestrial contamination is unlikely. However, contamination, no matter how unlikely, is a more mundane explanation than extraterrestrial life, and Occam’s Razor will always shave very closely here. We have to be very, very clear that contamination was impossible before seriously entertaining the idea that these structures are space-borne life.
It's a tantalizing possibility, one that if true could lend weight to the old panspermia theory, which holds that life on Earth was seeded by extra-terrestrial objects smashing into Earth. It's fascinating stuff, but let's take a wait-and-see attitude. 


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