We have yet to make contact with an extraterrestrial intelligence, making it exceedingly difficult for us to imagine what an alien civilization might be like. But that doesn’t mean we can’t make some educated guesses. Here’s what we know — and don’t know — about aliens.

Right at the outset I have to make it clear that this exercise is purely speculative. We’ve never met an extraterrestrial intelligence (ETI), nor can we even be certain they exist.

When we look into space, we see a seemingly rational and biophilic universe ruled by predictable laws — and it’s absolutely bursting with stars. Our galaxy alone hosts 400 billion of them. If we consider the entire visible universe itself, which may host upwards of 170 billion galaxies, there could be as many as one septillion stars. That’s a number with twenty-four zeros behind it (1024). Considering those figures, it would be improbable to the point of ludicrousness to suggest that we’re the only technological civilization across both space and time. Indeed, the universe may have started churning out intelligent civs as long as 5 billion years ago.

But there’s more to this exercise than just looking in awe at a star-filled universe that may or may not be friendly towards life. We have one very important data point to look at: Our own civilization. But it’s here where we have to apply some philosophical thinking.

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