Could these meteorites hold the first evidence of extraterrestrial life?

Scientists in Wales are claiming that they may have found fossilized microbes in meteorites that crashed to the ground a few years ago in Sri Lanka. The meteorites have a geological composition characteristic of comets, but when the researchers cracked them open they found something unexpected.

They discovered microscopic structures that look an awful lot like ancient algae found on Earth. According to the researchers, these space fossils' age and position within the meteorites suggest that they aren't the results of contamination and that they did genuinely originate offworld.

Right now, however, the evidence is purely structural — these look like algae fossils, but more testing is needed to verify that that's what they are. Over at Bad Astronomy, Phil Plait says they are absolutely not fossil life forms. He also explains why these may not even be meteorites here. So take this with a grain of salt.

Could these meteorites hold the first evidence of extraterrestrial life?

Technology Review reports:

The most startling claims, however, are based on electron microscope images of structures within the stones (see above). Wallis and co. say that one image shows a complex, thick-walled, carbon-rich microfossil about 100 micrometres across that bares similarities with a group of largely extinct marine dinoflagellate algae.

They say another image shows well-preserved flagella that are 2 micrometres in diameter and 100 micrometres long. By terrestrial standards, that’s extremely long and thin, which Wallis and co. interpret as evidence of formation in a low-gravity, low-pressure environment.

Wallis and co. also measured the abundance of various elements in the samples to determine their origin. They say that low levels of nitrogen in particular rule out the possibility of contamination by modern organisms which would have a much higher nitrogen content. The fact that these samples are also buried within the rock matrix is further evidence, they say.

Wallis and co. are convinced that the lines of evidence they have gathered are powerful and persuasive. “This provides clear and convincing evidence that these obviously ancient remains of extinct marine algae found embedded in the Polonnaruwa meteorite are indigenous to the stones and not the result of post-arrival microbial contaminants,” they conclude.

Read more on Technology Review, or read the researchers' report on Arxiv. Thanks for the tip, Matt MCC!