So, a team of scientists in the UK claims they’ve found evidence for alien life coming to Earth. According to their paper, published in the Journal of Cosmology (more on that in a moment) they lofted a balloon to a height of 22-27 kilometers (13-17 miles). When they retrieved it, they found a single particle that appears to be part of a diatom, a microscopic plant. This, they claim, is evidence of life coming from space.
Um, yeah. Except really not so much.
A Bit of History…
First off, I’ll note that the team publishing this paper includes one Chandra Wickramasinghe. This is the same man who has claimed, time and again, to have found diatoms in meteorites. However, his previous claims have been less than convincing: The methodology was sloppy, the conclusions were not at all supported by the evidence, and heck, he hadn’t even established that the rocks they found were in fact meteorites! He also has a history of seeing life from space everywhere based on pretty thin evidence.
Given that, any claims associated with his work should be taken with a large grain of salt. Moreover, this team published their results in the Journal of Cosmology, an online journal that doesn’t have the most discerning track record with science—see here and here and links therein (and even more in the links in the paragraph above) for plenty of evidence of this.
But what about their actual claims?
They found what appears to be a fragment of a frustrule, the hard outer casing around a diatom. It certainly does look like one. But is it?
Weirdly, they apparently didn’t even check. Seriously, in the paper they describe the photo of the object and say [emphasis mine],
On one stub was discovered part of a diatom which, we assume, is clear enough for experts on diatom taxonomy to precisely identify.
That implies very strongly they didn’t ask an expert in diatoms to look at their sample. That’s bizarre. If I were claiming this were an ET plant, that’s the very first thing I’d do!
Still, let’s go with it. Diatoms are endemic on Earth, found essentially everywhere there is water. Did this one come from Earth? They do claim they took precautions to make sure none could contaminate their sample, so that’s good. I wouldn’t rule it out, but again, let’s go with that as well. The diatom looks very like known species on Earth (they comment on this fact in the paper, actually). How would it get up to the stratosphere?
Volcanoes would be a possible mechanism, though they say no volcanoes had erupted recently, and claim that a particle that size would fall out of the stratosphere rapidly. But I’m not so sure that’s the case. They quote a paper showing how rapidly a particle would fall from various heights, and say the diatom would fall within hours. But I read the paper, and it assumes the atmosphere is stable and unmoving; it specifically mentions no other forces acting on the particle except gravity and buoyancy. There is, however, wind and turbulence in the stratosphere that could conceivably keep a tiny object like that aloft for quite some time. I’m not saying it did, but there’s no indication in their paper they firmly eliminated the possibility.
And just because they can’t think of a way to get it up there doesn’t mean there isn’t one. Given the alternative is alien life, for which we have zero other evidence (despite their linking to Wickramasinghe’s previous claims about diatoms in meteorites, which I am satisfied are wrong), they should try a lot harder to look for more mundane ways this beastie made it up there. They dismiss other pathways, just stating they won’t work, but I’m unconvinced.
Clearly, though, they are. In the paper itself they stop just short of claiming it’s alien for sure, but in the press release they are not so circumspect:
In the absence of a mechanism by which large particles like these can be transported to the stratosphere we can only conclude that the biological entities originated from space.
In other words, if they can’t figure it out, it must be aliens. This “god of the gaps” argument leaves me underwhelmed. They’re making an extraordinary claim: This diatom originated in space, perhaps in a comet, and got into the stratosphere as part of a meteor or meteoric material.
There are a lot of reasons to think this claim is unfounded, but one is right in their very paper. Look at the picture they published of the diatom (shown above): It appears clean, even pristine. As they themselves say,
It is noticeable that the diatom fragment is remarkably clean and free of soil or other solid material…
which would be incredibly unlikely if it did come from a comet or a meteoroid. Why wasn’t it embedded in some bit of rock? That point works against them more than it supports their claims.
It seems to me to be far more likely that like the other claims about diatoms from space, this is actually a case of one from Earth getting into their sample.
I’ll note that I find the idea of panspermia—life on Earth originating in space—really interesting. We certainly have good circumstantial evidence life could exist in space; conditions on Mars looked pretty good a billion years ago, and we’ve found amino acids in comets and meteorites. What we don’t have is direct evidence.
Panspermia is worth investigating, but it’s worth investigating correctly. Outrageous claims on thin evidence with huge conclusion-jumping don’t comprise the best way to do it. Stories like this one are sexy and sure bait for an unskeptical media, of course. But at the very least they don’t help the public understand science and the scientific process, and I know some scientists take an even dimmer view of it (for example, read this, and this).
The lead author, Milton Wainwright of the University of Sheffield, says he is “95% convinced” the diatom didn’t come from Earth. That may be the case, but the evidence given in the paper doesn’t support it.