Most of us are familiar with the basics of what Einstein discovered. One of those things is that nothing can travel faster than light. This isn’t relevant to our day to day lives, because we can’t possibly conceive of how fast light is. We can get a grasp on it when we think about distances where that speed is relevant. We’ve all thought about traveling the stars, about finding a new Earth or contacting aliens. When thinking on that scale, the speed of light is a very relevant thing. It’s possible future scientists will prove Einstein wrong or come up with some clever way that we don’t really break the rule, while breaking it in a practical fashion. For now, I’m assuming that doesn’t happen. Not because I’m convinced it’s the case, but because it’s a possible option and our societal view of the future doesn’t address it very well.
Here’s some facts that are relevant:
Light Year (ly) = time it takes light to travel that distance in one year (it’s very large, bigger than the solar system)
Nearby Stars: one at 4.5 ly, one at 8.5 ly, one at 10.5 ly, and four at about 11.5 ly
Span of our galaxy: 100,000 – 180,000 ly
Nearest galaxies (not satellites): 2,560,000 ly, 2,640,000 ly, and 3,390,000 ly
So with the most amazing engines following Einstein’s speed limit, we could reach those places in a little more than that amount of time. Four to twelve years for close stars, hundreds of thousands of years to cross the galaxy and millions to leave the galaxy. Communication across those spans would take just as long and twice that for a response.
Civilization would not be possible, at least not as we’ve come to know it. A 9-24 year delay for any communication is closer medieval speeds. We could colonize that local group of stars, hoping that there’s planets we can use in some fashion, but we’ll always remain separate. We have the potential to create a united humanity on earth, forging ahead with some grand goal. With some very advanced forms of organization we could manage it across the solar system. There is no hope beyond that.
So colonization is possible and even some interaction between the colonies. They’d never unite, but trade and immigration would be possible. We can remain optimistic, but that division would put us in constant danger of falling back into our violent ways. And with the weapons our technology could create…. Maybe this is the answer to the Fermi Paradox.
The span of the milky way effectively eliminates any possibility of humans colonizing it. Our physical and mental offspring may reach the edges of the Milky Way, but we certainly wont. Homo Sapiens have only existed for roughly 200,000 years. Our population size was vastly smaller for much of that time and also far more concentrated in a specific environment. We will not remain one species in the time it takes us to colonize the galaxy. We will not remain human. Even if we sent fertilized embryos on robotic ships, the variations that would evolve from one region to another would render us different species. It would be like the spread of language and writing across Eurasia. Each group would be somewhat similar to the one next to it, but the variations from one side to the other would be massive.
Within our galaxy we may not be able to colonize, but at least we can have some idea what it could look like. Not so on the next scale up.
Inter-Galactically it’s just too much to conceive of. Millions of years is beyond the point of even speculating with any shred of reality. The human mind can’t span that gap.
So what’s the point of all this speculation? We can draw one definite fact from it: Humans will not leave our small region of the galaxy. Maybe leave our solar system and reach nearby stars, but ultimately anything beyond say 1000 ly is beyond us.
We can send our seeds out there and hope for the best, but unless we breach Einstein’s ceiling we’re stuck here.