In a world with escape velocity greater than the speed of light, would a civilization be able to reach space?
Htrae is a planet with an abnormally strong gravity. In Htrae, the escape velocity is greater than the speed of light. Suppose a civilization like humans (call them snamuhs) evolves, with the unique ability to withstand Htrae's abnormal gravity. If the snamuhs have the ability to become as technologically advanced as possible without breaking the laws of physics, will they eventually be able to leave the planet Htrae and go into space?
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No, they will not be able to reach space. At least if we assume that our understanding of physics is correct. Since you do not state anything to the contrary, that's an assumption I am willing to make.
Basically, what you have is a (very small) black hole. A black hole is a mass that is so dense that the escape velocity becomes greater than the speed of light. In order to get that, you need absurd densities; for comparison, if our moon were to somehow magically collapse into a black hole of identical mass, it would have an event horizon the size of a grain of sand. At these scales, many of the equations we can use to describe our everyday world (including Newtonian mechanics and some of the simpler solutions to special and general relativity) are no longer valid. See also Are black holes very dense matter or empty? over on the Physics SE.
Because nothing can go faster than light, and the escape velocity of their world is greater than the speed of light, your species cannot accelerate beyond the escape velocity of their world, meaning they cannot leave it. Apparently (see the discussion in the comments to AmiralPatate's answer to this question) they won't even be able to establish a stable orbit around their planet, because the orbital velocity only drops below $c$ well beyond the event horizon, and being able to establish a stable orbit seems the lowest usable definition of "reach space", let alone leave the planet (suborbital spaceflight has very few applications that atmospheric flight cannot cover at a significantly lower cost).
Actually, though, it's worse than that. When dealing with the absurd gravities of black holes and similar objects, gravitational spaghettification becomes one of the things that you need to worry about. Basically, the gravitational pull is so intense that the difference in gravity is noticeable along macroscopic lengths, which destroys the matter that makes up objects of interest to us. Hence, even if we ignore the issue of real estate prices on such a tiny world, such beings could not possibly evolve, because there is no matter (as commonly thought of) that could come together to form these beings and remain in a coherent shape under the gravitational stress!
And in a way, it's even worse than that. If the planet is dense enough to have an escape velocity greater than the speed of light, I would love to learn more about the star it is in orbit around, because stars tend to be vastly more massive than their planets. For comparison, in our solar system, the Sun is approximately 1,047.8 times more massive than Jupiter, or 333,000 times more massive than Earth. If the planet has an escape velocity greater than the speed of light, that makes me wonder what its insolation from its sun is like...
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