ANALYSIS: Israeli Meteorite Misadventures
And then there's the meteorite fragments themselves. 628 fragments were collected from a large 10 kilometer-wide rice field fall zone, of which only three were positively identified by the team as originating from space. One sample is shown here.
But there's a problem... that doesn't look like a meteorite. It's kinda porous. And jagged-looking. It's crumbling a bit, too.
Usually meteorites are dense, smooth, dark rocks with a tell-tail fusion crust. Even fragments from a parent fireball don't look like that. But it's OK! They measured the oxygen isotopes contained within the samples to confirm "unequivocally" the ratios match that of known space rocks.
Sadly, as Bad Astronomer Phil Plait points out, there's no mention on how the team avoided carbonate contamination of the sample - contamination that can throw oxygen isotope measurements. "But even if they had (carried out the correct procedure), the non-standard oxygen isotope ratio is not proof of extraterrestriality, it just isn't necessarily inconsistent with it. So really, their claim that the isotope ratio proves ‘unequivocally' these are meteorites is wrong, plain and simple." So there's every chance that either the rocks are meteorites (but they were contaminated) or they are, you know, rocks. As in rocky rocks; rocks that came from the ground (on Earth).
Now... about those "aliens," that, interestingly, are never referred to as such in the publication. Remarkably well-preserved "fossils" (pictured top) of alleged diatoms that have allegedly been found inside the samples of alleged meteorite samples. Diatoms are a type of algae. Needless to say, the discovery of this type biology inside a meteorite would be historic. Unfortunately, despite the researchers' claims to the contrary, they are likely contamination.
ANALYSIS: Has Evidence for Alien Life Been Found?
"Wickramasinghe's team claims they found diatoms deep inside the samples, and therefore can't be contaminated," wrote Plait. "But this is incorrect. I've talked to biologists who look for life in rocks, and they say that contamination is a huge problem. These buggers are small and can find their ways into the smallest cracks and fissures." Also, as these "meteorite" fragments fell in a rice field - known to be a pretty wet place - contamination with Sri Lankan algae would probably be the most likely explanation.
At first glance, the research seems genuine, but after a little reading, it becomes clear that the correct procedure has not been carried out. Also, the fact that experts in the fields of meteorites and diatoms were not consulted is another red flag. This is not peer-reviewed science. Add all this to the fact that none of this work was published in a mainstream journal should be a warning that the extraordinary conclusions are baseless.
The hypothesis that life was seeded by hitchhiking microbes inside space rocks from planet to planet - known as panspermia - is grounded in real science, however. But there is currently no evidence supporting the hypothesis, so far. Personally, I think the hypothesis makes a whole lot of sense, but until we have real evidence to support this idea, it will remain a hypothesis, nothing more.
It is my concern that knee-jerk studies such as this and the inevitable tabloid headlines they produce cheapen the genuine science being done by astrobiologists. The search for extraterrestrial life, and potential transfer mechanisms like panspermia, is one of the most profound hunts of our time - in fact, of any time. It is critical that the scientific due diligence is done before claims of extraterrestrial biology is even hinted at.
For more detail and analysis, be sure to check out Bad Astronomy at Slate.com
Publication: "The Polonnaruwa meteorite: oxygen isotope, crystalline and biological composition," arXiv:1303.1845 [q-bio.OT]
Image: Wickramasinghe et al.