Aliens have been a part of science fiction for a very long time. You only need to look the success of Star Wars and Star Trek to see this. Both franchises suggest a galaxy teeming with alien life, from the cellular level to interstellar empires. Aliens that could be anything from a human with a bumpy forehead to a floating brain that can see through time. The infinite possibilities of an infinite universe suggest that there could genuinely be millions of alien races out there. Even if we haven’t met any yet, our fiction is full of them, and will likely be just as full of them for the foreseeable future.

But while they seem to be everywhere in the books I read, I’ve never been all that keen on aliens. While I love the cultural discovery angle they present, I prefer my SF on the harder end of the scale. Which is a real problem when it comes to English-speaking aliens that breathe our atmosphere. I’ve always wondered what a hard SF alien encounter could look like. Not so much in the near future, but in a more space operatic setting. What would the collision of two spacefaring species look like?

There are two aspects I’m looking at right now. The Fermi Paradox and the Kardashev Scale.

The Fermi Paradox is a fairly simple one, and not really a paradox at all. It asks a simple question: assuming Earth is not rare and there are thousands of aliens out there, why haven’t we met them yet. The two part answer is, as it so often with SF, space and time.

If the universe is infinite, then alien cultures are infinitely spread out. Even within our own Galaxy, empires could rise without ever coming across one another. Think how many undiscovered animals there are on Earth alone.

But the universe is not only massive, it is also ancient. Even if two species rose to control millions of star systems, they could do so millions of years apart. In that gap any trace of said species could disappear.

So. The likelihood of humans ever meeting aliens is vanishing slim. But imagine we could? After all, imagination is what our genre does best. What sort of aliens might they be?

This is where the Kardashev Scale comes in. It measures, in a very rough way, how much energy a species can harness. Level 1 can harness their entire planet. Level 2 their local star. Level 3 an entire galaxy. For reference, humans are currently less than 1, though that is a matter of infrastructure as much as technology.

Clearly this scale is less than perfect. Harnessing energy does not necessarily equate to technological advances, nor does it say anything about society. But it’s a good benchmark.

Level 1 planets are the most likely, and can develop fairly quickly. But they’re also vulnerable to calamity. A single meteor or solar event could wipe out any trace.

Any truly spacefaring species would likely be level 2. This is where they travel beyond their own star system. The majority of SF deals with aliens of this type. Quite frankly, they’re the most interesting.

At level 3, aliens are essentially godlike. As well as making for boring fiction, they would probably be bad to encounter in real life. A species that powerful probably won’t care for the likes of us.

These are all just general thoughts. I’m no scientist, just a writer. But I think these things are worth bearing in mind when it comes to creating alien races. Certainly they are things I would like to see reflected in the books I read. And if I can’t read them, I guess I’ll have to write them.