Solid Answer to the Question: “Y No Aliens?”

Solid Answer to the Question: "Y No Aliens?"

If you love science fiction, you’ve asked yourself: “Y No Aliens?” I mean, really … where are they? We’re all a little curious. Wouldn’t it be cool to play ‘Close Encounters’ the home game? Hasn’t happened yet, but on the flip side, at least we haven’t been colonized and used for slave labor in the Shilean salt mines. So we have that going for us, which is nice. Nonetheless, from a scientific standpoint, we’re left with the real question.

I don’t have the time or inclination to nerd out about this, but someone on Reddit does. There are rational, logic-based reasons for a lack of appearance by our universal brethren. Here, Astrokiwi provides us with a solid Answer to the Question: “Y No Aliens?”

This is a large part of the Fermi Paradox. The galaxy is only about 100,000 light years across, so even at 1% of the speed of light, it takes 10 million years to cross the galaxy. We evolved from small mammals to tool-using humans with space rockets over less than 100 million years. The invention of writing to the Apollo Program is maybe 10,000 years or less. All of these time-scales are much shorter than the age of the Earth, let alone the universe. This means that if life intelligent evolved anywhere else within the galaxy, it’s unlikely that it appeared at the same time as us – it’s almost certain that any intelligent life would be millions of years more advanced or millions of years less advanced.

This tells us that galaxy-colonising advanced life must be rare, as if there is intelligent life that has the capability and intent to colonise the galaxy, anywhere within the galaxy, anywhere in the past X million or billion years, they should have reached Earth a very long time ago.

Of course, there are multiple reasons why galaxy-colonising advanced life might be rare.

  • they lack the intent, i.e. they could colonise the galaxy, but they choose not to leave their home planet, or they do explore the galaxy but leave us alone (basically the Zoo hypothesis)
  • they lack the ability, i.e. even with millions of years of advancement it’s not practical to leave a solar system in mass migrations, or a more advanced society generally becomes more at risk of destroying itself before it reaches that stage (“the great filter”)
  • intelligent life is rare. Life has thrived on Earth for billions of years before one species developed spaceflight. Evolution doesn’t inevitably lead towards developing life that can invent advanced technology. There may be many planets out there full of animals and plants, or even just bacteria, but it’s possible that humanity is a bit of a freak accident.
  • life is rare in general. We don’t really know how common life is. We know the ingredients seem to be fairly abundant, but how often do these combine to make something we would reasonably call “life”?
  • the conditions for life are rare. However, as we discover more and more exoplanets, it looks like there are quite a few planets that seem like they would be hospitable to life, so this is less of a factor than we used to think.

So this isn’t really a “paradox” in the common sense, because there are many ways to resolve it. But each of the resolutions involves stuff we just don’t know – we don’t know how frequently life evolves in the right conditions, we don’t know how frequently life evolves to form intelligent space-faring species, and we don’t know how often a space-faring space faring species would have the intent and capability to explore the galaxy. Any of these are plausible, and it could easily be a combination of everything.

So there you have it. A relatively simple, yet solid answer to the question: “Y No Aliens?” I’m a little wiser, but disappointed, that I won’t be able to trade my parents in for a star cruiser this year. In the meantime … keep watching the skies!

Also: I got turned onto a new scifi comedy podcast this week: Dark Air with Terry Carnation is a satire that answers “what if Fresh Air met Art Bell?” Rainn “Dwight Schrute from The Office (US)” Wilson stars as Terry Carnation and the callers (People like Nathan Fillion, Sam Neill, and Jason Reitman play cameos) are as weird as the premise.  It’s the same type of humor I used in ‘Planet Ugh,’ so if you’re a sci-fi fan, this is a must-listen. Check out Dark Air and start laughing now!