I hope that this the case, otherwise humanity will die on this planet. If there are no new physics then there is no faster-than-light travel and escaping earth will be pretty much impossible.
Although it brings to mind the irony that if one has the capability to live in space within artificial environments indefinitely, gather resources within it, and produce more of them there isn't technically a need to find any habitable planets. If such a state is reached there are only two things to worry about - self destruction and entropy or cosmic scale events that a planet wouldn't be safe from anyway.
(The same way inventiveness doesn't matter if you found yourself in the middle of Antarctica with no food, no heating, and no materials to make a compass).
I think if the Earth was something like 40% more massive, we wouldn't be able to leave the surface with chemical propulsion.
This QA goes more into this observation: https://space.stackexchange.com/questions/14383/how-much-big...
From what's there it looks like it's a lot higher than 40% as a limit.
And the technology is pretty much there, it's just that the will isn't.
Is taking an FTL ship to another galaxy, even with a known habitable planet, that much easier than creating a dome city on Mars? What if they're barely habitable?
Who is going to do that and what for? Same resources, and no one wants to because Earth already has it all (and yes, by the time they're exhausted, it will be too late for anything).
Colonize the solar system, and if FTL is created, great, if not, meh.
To the other side of the galaxy it would be 12 years
https://en.wikipedia.org/wiki/Space_travel_using_constant_ac...
Going to Mars using antimatter with the same 1g acceleration the entire time (reversing half way) will take a few weeks and require a small fraction of a gram of antimatter.
Ignoring the significant engineering problems like heat disappation, storage if it's not used instantly, you could get two years worth of thrust from antimatter measured in grams and cross the galaxy in just over a decade, in Earth time the trip would be >100,000 years.
Besides, we can always travel the slow way. Either with ships built for multi-generational habitation or some way to suspend/resume human life over long periods.
> No, that would have the same problem - being able to send information back in time.
Would it? If a wormhole is connecting two points in spacetime, then could time also be traversed at the same time? E.g. traveling through the wormhole would move you far enough forward in time to not cause any problems?
Well, the assumption abiut causality is based on our current understanding of physics. Perhaps we just don't understand the problem well enough and there are ways around the causality problem
In the long term, we have the entire solar system to work with, which should be plenty to keep us going for a very long time. The Earth is just a small fraction of what's available even if we're stuck with our sun. Frank Drake from SETI thinks that alien civilizations have no good reason to ever leave their home stars, because a star will provide all the energy they will ever need, and traveling light years just isn't worth the cost (assuming no FTL).
I mean, for comparison humans have been around in a modern form for about 50,000 years... well the chances of something not happening then are few and far between. Probably could have launched millions of generation ships between now and then.
Interstellar travel and colonization does not necessarily need superluminal travel; it could be done with sub-lightspeed spacecraft capable of hosting multiple generations of humans for many decades, possibly centuries.
However getting Earth's nations to cooperate on such a long-term undertaking may be no less difficult than achieving FTL travel.
[1] Meaning that, though it's not logically ruled out, you need flying Spaghetti Monster level subterfuge to make it compatible with what we know to be true.