I have seen approximately eleventy bazillion scifi/horror movies where someone sees a meteor, it hits the ground, they go over to investigate, and the meteorite infects them with some sort of alien microbial goo that turns them into the Blob or the nearest trope equivalent. 

But what happens if we find a meteorite and it is chock full o’ life? What then?

Well, it’s happened. Kinda. And it’s a serious problem, though not in the way usually depicted.

It wasn’t a meteorite per se, but samples of an asteroid brought back to Earth via spacecraft (also a scifi stereotype, for what that’s worth). In 2014, the Japanese Space Agency JAXA launched the Hayabusa2 spacecraft to the asteroid Ryugu. Its mission was to map out the asteroid, take tons of data, and then scoop up a sample to send to Earth. It performed beautifully, and in December 2020 the sample return capsule landed in Australia carrying 5 precious grams of asteroidal material.

Having these on hand is a huge scientific boon. Meteorites come from asteroids, but we can’t always know which asteroid. Plus once they land on Earth they get rained on or snowed on or fall in a swamp and then picked up by people and moved around, all without any sort of contamination protocol, so it’s hard to know what’s actual asteroid and what glommed off of someone hands who didn’t wash the last time they ate a messy sandwich. 

These pristine samples of Ryugu also are time capsules from the early solar system, relatively unaffected by the ravages of time and events since. Studying them is like having a time machine set to 4.6 billion BCE. 

The samples were secured at Japan’s Planetary Material Sample Curation Facility, where scientists could study them in clean and controlled conditions.

What did they find? Well, not to put too fine a point on it: life. Yes, actual life, prokaryotes that were busily building a microbial community inside the alien rock.

[Link to research journal article]

So why don’t you hear about scientists bellowing about this from the rooftops of every research facility across the planet, screaming “ALIEN LIFE!!!” to every reporter who will listen?

Because yeah, it’s life, but it’s not alien. It’s us.

Or more accurately, Earth life. The microbes are almost certainly terrestrial that somehow got onto the samples. So how did this contamination happen? The protocols for containing the samples in the return capsule, moving them to the facility, and storing them are tight, and very probably kept the samples pristine. But the team of scientists who studied the microbes did something clever: they watched the wee beasties multiply in the sample over 64 days, and backtracked the growth to get a date for when the contamination likely occurred. The time fits well with when the rock was cut to prepare it for initial examination, so it’s likely the infiltration happened at that time.

The obvious lesson here is that we need to have better protocols at all stages of this sort of thing, but especially when the samples are being handled for preparation. 

But there’s another point, and one that’s actually scientifically very interesting indeed: terrestrial organisms were able to survive by metabolizing (eating, if you will) material from an asteroid! That’s phenomenal.

This has been studied before; scientists cultured bacteria on a type of meteorite called a carbonaceous chondrite. All the basics can be available for a yummy microbial repast, including things like carbon, sulfur, and iron, with water locked into asteroid material as well. So our local microorganisms were fruitful, and multiplied.

That’s just cool. Plus it implies, however speculatively, that microbes could live on asteroids. The lack of atmosphere and the exposure to intense sunlight (including ultraviolet light) would make it difficult, though, to say the least, but it’s fun to think about. 

It also highlights how easy it is to contaminate a sample. If this can happen to one that’s had serious engineering to keep it safe, how likely is some kind of infiltration for a space rock someone finds sitting in their front yard?

…which sparks a memory. In 2009 and thereabouts I was busily involved with making a TV show for the Discovery channel called Phil Plait’s Bad Universe, based on my book Death from the Skies! In the biz it’s what’s called a back door pilot; a three-part miniseries meant to test the waters and, if it performs well, could then be expanded into a full-blown series. That didn’t happen, which is a tale for another time. 

The overall plot was about dangers from space, including for example asteroid impacts and solar storms. The second episode was about alien invasion; yes, seriously. We dealt with the possibility of actual technologically advanced civilizations coming to Earth, but also about the likelihood of being infested by alien bacteria and viruses. The conclusion, of course, is that any and all of this is not going to happen in any real sense.

But at one point we went spelunking in a cave in New Mexico to look at extremophiles, bacteria that live in hostile conditions and grow very slowly. We also visited a lab where scientists were examining such things, and I was standing over one biologist’s shoulder as he showed me microphotographs of slices of meteorites. As he paged through them, one showed a very obviously biological structure; it looked like two fried eggs next to each other, and, more to the point, like a cell caught in the act of mitosis. 

I remember exclaiming when I saw it, and we did a little aside on the program about it. Could it be evidence of alien life in a meteorite?

Here’s the thing: Yeah, no. It was almost certainly contamination from when the rock sat on the ground or in a lab or during processing. At the time I wasn’t really well versed on such things, and so it went into the episode. I’m embarrassed about that now, but that episode had a few other behind-the-scenes issues that I wish could have been caught in time. Again, a tale for some future moment.

Anyway, since then I’ve debunked lots of claims of such things, including a crackpot whose whole raison d’etre seems to be thinking that life on Earth started in space and was brought here by meteorites, and he has claimed that he has found diatoms in meteorites, which, to be clear, is baloney (feel free to insert stronger language there if you care to).

The point is, microbes in meteorites is a whole thing, ranging from garbage pseudoscience to being a thorn in the side of real scientists trying to study asteroids. And there is a chance, a very teeny small one, that maybe someday we find something on an asteroid or comet. It’s much more likely we’ll find the precursors of life, building blocks like proteins and such (amino acids, the building blocks of proteins, are common in space).

In the meantime, this paper about contaminated Ryugu samples just came out last week, so be aware that if it gets picked up by mainstream sources it’ll likely make its way to the usual chuckleheads on Tiktok and other places who will talk about aliens and UFOs and coverups despite the fact that actual scientists wrote an actual paper on this and published it in an actual planetary science journal which anyone can read. Arg.

So screw them. The science on this is pretty danged cool, and keeps us informed about the real universe. Turns out, it’s a pretty interesting place. 

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