How do you propose to travel for over 20 years?
It's clear then that robots will be exploring the solar system, not us. Even then it's going to take several centuries just to travel to, collect data from, and send back to earth just from the local stars we can see with the unaided eye.
When they say space is big, space is BIG.
Or if we can't do that (which would be weird since many complex mammals can hibernate already) then generation ships are possible. It'll probably be only done by culturally crazy groups, but hey! They're still counted as humans, and their expanding human habitats into new systems is still a win to us all.
We're not going within my lifetime, but we don't know what currently-unimaginable technologies could be developed in the future (if we don't destroy our civilization within the next few decades)
Significantly extending the lifespan of humans seems inevitable at some point. Robotics and AI will continue to improve. We may master fusion, or discover new ways to store energy. We'll probably mine asteroids and master construction in space.
Robots will lead the way, but humans are unlikely to lose the urge to explore.
The most important point to realize about science fiction is that it is fiction.
We should tell it to physicists ;-)
That was the same in 1700s. Laws of mechanics were well known and they were convinced that it was just about getting better in using math with it.
Then electricity and magnetism emerged.
Then nuclear physics and quantum theories and relativity.
And we know very well that they don't match up.
And we have anomalies all over in our measurements and no good theory to explain them.
But just using "known" physics theories we have warp drives and warmholes and quantum teleportation.
Going to the moon was something impossible and we accomplished it.
Before the same was for flying or going deep underwater.
Do you need more examples to get some fate?
https://www.sas.upenn.edu/~dbalmer/eportfolio/Nature%20of%20...
Our knowledge is incomplete, but we can put boundary boxes around what is possible. Just because our theories are incomplete doesn't mean that what we know is wrong. Our knowledge has been extensively tested over the past 100 years.
Based on our incomplete knowledge. So we really can't. What would a proof that something is physically impossible look like?
Newton was wrong, Einstein has provided us a better, more accurate, theory of gravity. Guess what? We still teach Newton in high school and college physics! Why? Because though it's wrong it's only wrong in the most extreme circumstances. Generally speaking it works quite well. The only observation we made contradicting Newton was Mercury's perihelion precession. But Einstein didn't change how fast apples fall to the ground.
Likewise, we know, or at least strongly suspect, Einstein is wrong. That doesn't mean everything we've observed the past 100 years corroborating General Relativity goes out the window with a new theory. No, instead that's what makes creating a new theory hard: you have to account for a century's worth of observations validating GR and reconcile with QFT (otherwise why bother).
But it wouldn't change anything about what we already know and what we've observed. That's why it's a boundary box. This is science, not magic.
Notably, the idea that a new theory simply takes existing "observations" and adds to them is historically unfounded. Indeed, many theories start as thought experiments that contradict observation and later turn out to be better models, not the other way around.
You also may or may not be familiar with the concepts of theory-ladenness and the commensurability of theories. If not, I suggest doing some reading about that so you can appreciate why those questions aren't as straightforward as you seem to believe.
[1] https://en.wikipedia.org/wiki/Theory-ladenness [2] https://en.wikipedia.org/wiki/Commensurability_(philosophy_o...
This is important in this discussion because we've never observed anything traveling faster than the speed of light in a vacuum. That would appear to rule-out faster-than-light travel, which for practical reasons would make traveling to other solar systems impossible.
Sorry, that simply isn't true. Multi-generation starships don't violate any laws of physics.
> How do you propose to travel for over 20 years?
By recognizing that you aren't coming back, and that even if you don't make it there, your children will.
I mean, we have examples of this even here on Earth. Moses and the Israelites supposedly wandered for 40 years. The pioneers who set out on the Oregon Trail largely knew it was a one-way trip. Other examples abound..
That's true - but they do violate what we know about psychology. You're signing on your progeny to be imprisoned on a ship from birth to death, when you yourself never had to endure that. Think about the sentiment behind the "Okay, Boomer..." memes and magnify that generational hatred several-fold. Someone is going to sabotage the ship and its crew long before they ever reach their destination. That's just how people work. Remember, we're not rational.
Plenty of people have lived out their lives while rarely or never leaving their small town.
In fact, that was the default for most of human history.
How is that going to work for your population confined to a ship the size of a small town? It isn't. It's science fiction.
Future generations may grow up in a world of much more limited travel, existing in small areas of '15-minute cities' without cars, minimal access to air travel, living in tiny apartments, and most likely spending most of their time in some sort of metaverse, with very limited food choices. We'll have stopped burning fossil fuels and given most of the planet back to nature, and can't allow the working-class masses the transport/freedoms to access/enjoy/ruin it again.
If that's what the world comes to, it'll be a lot closer to life on a generation ship than the world we're used to today.
Not that any of this solves the problem of humanity having nowhere to go. The trip is ultimately futile since the stars you're going to are also dying.
Some did. Most stayed in their little town for their entire lives.
> How is that going to work for your population confined to a ship the size of a small town?
The same way it worked for small towns before mass transportation was available.
It's a step on the way to going even further, beyond our solar system.