4 ms·

"imposed by known physics" I've heard a physicist say that we do know a lot about what's possible physically and that isn't going to change with more knowledge

"imposed by known physics" I've heard a physicist say that we do know a lot about what's possible physically and that isn't going to change with more knowledge. Is that really true or just short sighted hubris? If we don't go extinct and keep progressing for 500,000 (or 50,000,000) more years, are we confident that we aren't going to get FTL travel? The answer to this question seems to bear a lot on the probability of alien visitation.

krapp 5y ago
It can't simply be short sighted hubris since the value of the speed of light as a constant derives from Maxwell's equations, and the relationship between mass, energy and the speed of light come from relativity, and that's a lot of science to have been wrong about all along. If FTL is possible, it's possible in a universe that has all of the properties of one in which it is impossible, where the math which most accurately describes it says it's impossible, where all of our experiments validate it to be impossible, and all of our technology that depends on those models (such as GPS satellites, which have to take relativistic time dilation into account to remain synchronized) still works. That doesn't seem likely. Also, there's the matter of the Fermi Paradox. The lack of any evidence of widespread interstellar colonization suggests that FTL isn't possible.
- fighterpilot 5y ago
  > It can't simply be short sighted hubris What about warp drive tech, are we reasonably confident that that won't be possible in 50 million years? Also, what about travel through wormholes. If an advanced civilization sent probes out 2 billion years ago that travelled at 0.5*c and created wormholes, couldn't they feasibly now travel FTL in a 1 billion light year radius? > Also, there's the matter of the Fermi Paradox. Right, but we're talking about whether some UFOs are actually alien visitations. For the people that think that, they believe the Fermi Paradox isn't really a paradox because aliens are already here.
  - krapp 5y ago
    The problem with warp drives and wormholes is that so far they only exist on paper and require things like negative mass and exotic matter or an entire Jupiter's worth of mass energy to even theoretically be feasible. Even then, there are some models which suggest neither would actually work for FTL travel anyway. If you want to stick to we can actually prove, wormholes don't exist, and neither does negative mass or exotic matter, and we have absolutely no idea how to actually create a "warp bubble," like none. Otherwise you could just as well invoke divine intervention or simulation theory. Although that would make for an interesting sci-fi story. It turns out the secret to FTL travel is discovering the universe is a simulation and hacking it, and the solution to the Fermi Paradox is being caught by the universe's AV software. It isn't hubris to doubt when all of the available evidence points in that direction, it's hubris to dismiss all evidence to the contrary and assume that all scientists and skeptics are simply short-sighted when all you have to contradict them is a low-resolution, blurry photo or video of some dots in the sky.
    - fighterpilot 5y ago
      Even if these particular theoretical approaches to FTL are later shown to be impossible, couldn't there be other ideas later on that we can't foresee (in terms of manipulating space, not necessarily travelling through space at > c)? Isn't human history littered with such examples? How long have we been doing physics for, and how stupid are we as a species? It seems that you place the subjective probability of either the wormhole/warpdrive ideas working out, or some as-yet undiscovered alternative coming about in the distant future, at sub-1%. To me that seems quite low. This seems distinct to me to saying that a specific math proof will be true eternally, since that's a deductive pursuit. Also FTL doesn't seem to be necessary. An alien civilization could feasibly have sent out Von Neumann probes at sub-light speed and have populated an extremely large radius over the span of a few billion years. > low-resolution, blurry photo This is a common refrain, but there exists high quality UFO footage. It could all be CGI or ball lightning, and the burden of proof is higher than mere video, but not all footage is low-quality.
      - krapp 5y ago

krapp 5y ago

It can't simply be short sighted hubris since the value of the speed of light as a constant derives from Maxwell's equations, and the relationship between mass, energy and the speed of light come from relativity, and that's a lot of science to have been wrong about all along. If FTL is possible, it's possible in a universe that has all of the properties of one in which it is impossible, where the math which most accurately describes it says it's impossible, where all of our experiments validate it to be impossible, and all of our technology that depends on those models (such as GPS satellites, which have to take relativistic time dilation into account to remain synchronized) still works. That doesn't seem likely. Also, there's the matter of the Fermi Paradox. The lack of any evidence of widespread interstellar colonization suggests that FTL isn't possible.

fighterpilot 5y ago
> It can't simply be short sighted hubris What about warp drive tech, are we reasonably confident that that won't be possible in 50 million years? Also, what about travel through wormholes. If an advanced civilization sent probes out 2 billion years ago that travelled at 0.5*c and created wormholes, couldn't they feasibly now travel FTL in a 1 billion light year radius? > Also, there's the matter of the Fermi Paradox. Right, but we're talking about whether some UFOs are actually alien visitations. For the people that think that, they believe the Fermi Paradox isn't really a paradox because aliens are already here.
- krapp 5y ago
  The problem with warp drives and wormholes is that so far they only exist on paper and require things like negative mass and exotic matter or an entire Jupiter's worth of mass energy to even theoretically be feasible. Even then, there are some models which suggest neither would actually work for FTL travel anyway. If you want to stick to we can actually prove, wormholes don't exist, and neither does negative mass or exotic matter, and we have absolutely no idea how to actually create a "warp bubble," like none. Otherwise you could just as well invoke divine intervention or simulation theory. Although that would make for an interesting sci-fi story. It turns out the secret to FTL travel is discovering the universe is a simulation and hacking it, and the solution to the Fermi Paradox is being caught by the universe's AV software. It isn't hubris to doubt when all of the available evidence points in that direction, it's hubris to dismiss all evidence to the contrary and assume that all scientists and skeptics are simply short-sighted when all you have to contradict them is a low-resolution, blurry photo or video of some dots in the sky.
  - fighterpilot 5y ago
    Even if these particular theoretical approaches to FTL are later shown to be impossible, couldn't there be other ideas later on that we can't foresee (in terms of manipulating space, not necessarily travelling through space at > c)? Isn't human history littered with such examples? How long have we been doing physics for, and how stupid are we as a species? It seems that you place the subjective probability of either the wormhole/warpdrive ideas working out, or some as-yet undiscovered alternative coming about in the distant future, at sub-1%. To me that seems quite low. This seems distinct to me to saying that a specific math proof will be true eternally, since that's a deductive pursuit. Also FTL doesn't seem to be necessary. An alien civilization could feasibly have sent out Von Neumann probes at sub-light speed and have populated an extremely large radius over the span of a few billion years. > low-resolution, blurry photo This is a common refrain, but there exists high quality UFO footage. It could all be CGI or ball lightning, and the burden of proof is higher than mere video, but not all footage is low-quality.
    - krapp 5y ago