[fleddr]

Exactly. For an optimist, we might one day colonize Mars. Next, getting out of our solar system is incredibly unlikely as the first habitable destination in our own galaxy is just so far away.

Say we stretch our optimism and do make it. Now the colonization of the Milky Way starts. It's a 100,000 light years to the other end. You'd be a completely different species by the time you arrive. Say you achieve that (you won't), now we need some type of coordination and communication. Suck badly though that messages have a delay of 100.000 years. There is no such thing as the human species if we spread out as the delay between even closest habitable zones would be so large that orchestration is impossible.

And we're still within the bounds of a single galaxy, not even intergalactic travel. It simply can't be done. We'll never even escape the solar system.

Long before that would even become a question, it's questionable whether our species continues to exist in its current form. Human level AI is at the horizon within our lifetime. And will then accelerate away. Add a few centuries to that and it's strange to assume we'll still be there, unchanged, as primates controlling a machine a billion times more intelligent. The only path would be to become a machine instead, slowly replacing biological parts with superior silicone. Until nothing biological remains.

Sounds crazy or unlikely? The idea that we remain as-is is far crazier.

[pharke]

I don't think we will remain as is but I also don't think we will never leave the solar system. Everyone seems to miss the next great technological advance that's currently under way. Biology as a practical science is still in its infancy. We haven't yet learned to fully control the cell and its many forms and functions but I don't doubt that we will given enough time. Once we do, there is no reason we could not adapt fully to space travel.

[rewgs]

It's very late and I don't have the energy to look up the math, but:

Assuming you're traveling at light speed across the Milky Way, a distance of 100,000 light years, the trip would take 100,000 years for the person traveling, no? I wonder then how long it would be for everyone left on Earth. Millions of years?

[ncmncm]

No.

The closer you get to light speed, the less time it seems to you to take getting there. If you could get close to light speed, "only" 100,000+ years would pass back home, never less, but could be any larger amount. At 1/10 light speed, a million years pass back home and almost a million on board.

If you don't get really, really close to light speed, it still takes thousands of years, on board.

Getting close takes way, way more energy than (e.g.) getting to half light speed did, which itself takes unimaginably much; getting to 3/4 takes way more than getting to 1/2.

You probably can't carry enough material to produce that much energy, but everything you encounter on the way is blasting you at a good fraction of lightspeed. Maybe a laser from home can keep providing you energy, but that has to keep working for 100,000+ years. The faster you go, the less energy it can provide; and the farther away you are.

[rewgs]

So, even though “100,000 light years” means “it will take 100,000 years to travel this distance at the speed of light,” those traveling won’t experience it as 100,000 years, but rather a much shorter time period? How long would the travelers experience that as?

To be clear I’m not talking about “almost light speed,” I’m talking about traveling at exactly the speed of light (ignoring for a moment whether that’s possible).

[ncmncm]

At exactly the speed of light you would experience no duration at all. But it would take infinite energy to get going that fast, and infinite energy again to stop, and would still take 100,000 years as seen by anybody watching at either end.

[rewgs]

Ah got it. Mind-boggling. Thank you!

[abhishekjha]

>The only path would be to become a machine instead, slowly replacing biological parts with superior silicone. Until nothing biological remains.

Reproduction has to be intact. But I do agree. We as a species are not fit to these interstellar or intergalactic travels. It has to be dominantly machines.

[folbec]

C. Stross - Saturn's Children.

https://www.amazon.com/Saturns-Children-Freyaverse-Charles-S...

[hoseja]

No it doesn't; if you replace the blind captain with a seeing one.

[7thaccount]

SETI scientist Paul Davies says his belief is that "all biological life is transitory". Essentially a temporary blip on the road to something greater. I assume he just means intelligent life.