[taylodl]

We're not going beyond our solar system. Ever. The nearest star is 4 light-years away. Assuming you could even travel at the speed of light, which you can't, it takes 1 year to reach the speed of light while accelerating at a comfortable 1G. But, as I said, we're not ever traveling at the speed of light. 20% of the speed of light is about the best we'll realistically ever be able to do - but that still makes the nearest star over 20 years of travel away!

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.

[Turing_Machine]

> We're not going beyond our solar system. Ever.

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..

[taylodl]

> Multi-generation starships don't violate any laws of physics.

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.

[Turing_Machine]

Any practical multi-generation starship is going to be the size of a small town, at a minimum, with open spaces and greenery inside.

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.

[taylodl]

Yet they yearned for adventure - and many, many people went on such adventures. Now we live in an age of mass transportation where people routinely leave their towns to venture elsewhere. They take airplanes to fly to different parts of the world, they take their cars to go on trips, they go on cruises: they travel. They may live in the same town in which they grew up, but they've travelled quite further.

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.

[bluescrn]

> Now we live in an age of mass transportation where people routinely leave their towns to venture elsewhere

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.

[taylodl]

That world you describe is a dystopia and it would probably be better for humanity to wink-out at that point. Then again, maybe by then we'll have bio-engineered ourselves to have a native port into VR working directly with our visual cortex. Then again, by the time we get to the point we need to be serious about getting out of the solar system (100 million years) we arguably wouldn't even be the same species as today - especially as we'll have been bioengineering ourselves for millions of years by that point.

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.

[Turing_Machine]

> Yet they yearned for adventure

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.

[bluescrn]

> We're not going beyond our solar system. Ever.

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.

[taylodl]

I'm sorry. We know physics very well. There's no "unimaginable technologies" that are going to be developed that gets us around the fact that we're not going to travel much faster than 20% of the speed of light - and that doesn't change the fact that the average star you see with your own eyes is 60-100 lightyears away and will by dying at roughly the same time as our sun.

The most important point to realize about science fiction is that it is fiction.

[AlessandroF6587]

> We know physics very well.

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?

[taylodl]

I think it's very important to understand the Relativity Of Wrong.

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.

[davidivadavid]

> we can put boundary boxes around what is possible

Based on our incomplete knowledge. So we really can't. What would a proof that something is physically impossible look like?

[taylodl]

Did you even read the article I linked?

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.

[inawarminister]

There are people that will be willing to lose decades of subjective time getting iced.

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.