Interstellar Travel Statistics

Daydream with me. Let's assume, for the sake of argument, that Drake's Equation is basically correct and 2-10 civilizations as advanced as ours or more exist at any given moment in this galaxy. Given the size of the galaxy, and the number of stars in it (about 400 billion), its pretty unlikely that we would ever hear from them or they from us. I mean, that's something like 1 civilization per billion stars.
But what ho! Ours is not the only galaxy in the cosmos. In our known universe, recent estimates are that 70 sextillion stars exist. Which, plugging this number into the Drake Equation, means that there are potentially 70 trillion races of creatures as advanced as ours in the universe right now. That's 10,000 entire civilizations per human currently on Earth. Side note: I am taking the pessimistic interpretation of the Drake Equation. If optimists are right, add three zeros to the number of civilizations I used.

So it's not hard to believe that with so many civilizations, at least a few hundred million of them predate ours by several millenia. It's not impossible to also believe that of those, a few hundred thousand have the fortunate luck to be on a planet circling a star with more than one habitable planet. Of those, a few thousand have surely sent colonists to the other planets and habitated there, spreading their race and becoming one of the rare civilizations to reside on multiple planets.

Given all this, it isn't hard to believe that of those few civilizations that are equipped to colonize neighboring planets, at least a few hundred or so also have a nearby star system with other habitable planets. Certainly a hundred or so of these civilizations have had the tenacity to send colonists across the cosmos, landing them at that nearby star's planet, staking a claim, and ensuring the survival of their species beyond the death of their home star. And while the civilizations were doing this, at least half of them devised methods to travel back and forth between solar systems with a high rate of speed.

So, once again for the sake of argument, let's assume that faster-than-light FTL travel is indeed possible, given enough energy and a high enough level of technology.

So you've got several dozen civilizations with the ability to travel between stars rapidly. A dozen of these have the gumption to go to other star systems near their own and build Dyson Swarms around those stars, capturing enormous amounts of energy. They use this energy to charge the power systems that supply their FTL engines. And given the ability to travel faster than light, these civilizations can now hop from star to star, setting up camp and colonies.

And like I said, the Universe is not young. It's as likely as not that these civilizations may be millions of years ahead of us in the game of Life.

Given 70 trillion civilizations in a Universe that is 14+ billion years old, and given that ours went from furry tree-dwelling animalia to nuclear-armed, space-exploring bipeds in a mere 2 million years...and went from spear-throwing nomads to industrialized nations in a couple thousand years...it becomes statistically improbable that out there in the Universe there are no other intelligent beings. It becomes statistically unlikely that no other intelligent beings are more advanced than we are. And it becomes doubtful that no species of creature in the Universe has mastered interplanetary travel.


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