Complex Numbers

It Was Aliens

When faced with the unexplained, obviously, the explanation is aliens.

The Guy Who Discovered DNA Thought Aliens Sent It  

How did life on Earth start? No one knows.

But we have some pretty compelling hypotheses.

We know all about evolution and DNA replication...

No, we do not.

...much more than our ancestors did, but we still have nothing but theories when it comes to explaining how nonliving matter ever started living.

Cracked here is using "theories" in its layperson sense, not scientifically.

One theory says this process, abiogenesis, never happened on Earth at all. Life came to Earth fully formed as simple microbes from some other planet, then it spread and evolved. Earth has never had the conditions for abiogenesis as far as we can tell (whatever those conditions might be), but an alien planet could have those conditions.

Except that we're pretty sure Earth did have such conditions at one point.

I'm sure I've mentioned this before, but going to "aliens did it" just kicks the can down the road. What we know beyond any reasonable amount of doubt is that life, somehow, started; as evidence for that, well, look in a mirror: life on Earth exists. I'm not saying it definitely, absolutely, got its start from non-life here on Earth, but I think we'd need to rule that out before jumping to any extraterrestrial origin hypotheses.

Which doesn't mean that I think life doesn't exist elsewhere also. I'm just saying it's within the realm of possibility that nonliving matter began to do its organizational thing right here in our own oceans, leading eventually to the development of DNA, cells, mitochondria, and, eventually, Instagram influenzas, without aliens being involved in the process. Though I'm still not sure about the influenzas not being aliens.

Francis Crick—Nobel prize winner and part of the team who first observed the structure of DNA—weighed in on the subject in 1973.

Crick, of course, didn't work alone (James Watson got co-credited for the discovery, which happened almost exactly 70 years ago), and there's good reason to believe that it was Rosalind Franklin who actually discovered DNA as such, though for some reason—I can't quite put my finger on it—he got a Nobel Prize but she did not. None of this, however, diminishes Crick's contribution to the field. Going on about aliens might, though.

The idea that spores from a different planet just happened to make their way to Earth ("panspermia") is too unlikely, said Crick. But you know what he said is a lot more likely, and which we have to consider? A theory dubbed "directed panspermia": Aliens seeded life on Earth on purpose.

Again, sure, maybe. We don't know. But we shouldn't jump to that conclusion. (Also, it's entirely within the realm of possibility that spores can survive interstellar travel.) And it still doesn't answer the actual question, which is: how does nonlife become life? That is, whether it happened here or elsewhere.

Crick also had some more specific arguments beyond this speculation (at one point in his paper, he says, "the psychology of extraterrestrial societies is no better understood than terrestrial society," realizing his reasoning is getting kinda "out there"). Life evolved to require such rare elements as molybdenum, which would make more sense if it started somewhere in which that element was more common. Also, Crick discovered that all life shares a universal genetic code, which is odd but would make sense if we all evolved from one kind of germ that infected our planet. That germ's home planet, however, probably had numerous separate very different genetic codes.

That's a whole wheelbarrow of speculation right there. I'm certainly not an expert in biology, but there are multiple ways that rarer elements can get concentrated here on Earth through natural, pre-biotic processes. If that weren't the case, we wouldn't find deposits of said elements. All it would take would be one well-placed deposit. One straightforward way is a meteor hitting Earth, which I suppose actually qualifies as an extraterrestrial origin, though not "directed panspermia." Around the time that life started here on Earth, there were a lot more meteors flying around.

As for the "life shares a universal genetic code" thing, that can be explained by DNA out-competing any other potential blueprint for life, analogous to how sapiens eventually out-competed neanderthals.

We're all comforted to learn that aliens might have sent life to Earth, like in Prometheus.

No, I'm not comforted by that at all; I'd still want to know how life began in the first place, here or elsewhere. Not that comfort has anything to do with science. Besides, I didn't like that movie.

At least this article correctly labels this as "speculation." Speculation is an important part of science. But just because someone's a Nobel Prize winner doesn't mean they're always going to be right.

Occam's Razor indicates that we shouldn't needlessly multiply entities, and throwing sentient aliens into the mix absolutely multiplies entities unnecessarily. It's equivalent to saying "we don't know, so God did it." Sure, it could turn out that he was right all along. I'll be sure to ask the aliens when they finally show up here.