This piece argues that antimatter could be feasible for space propulsion and we could start developing it now: https://news.ycombinator.com/item?id=46073414
https://youtube.com/watch?v=i6jMnz6nlkw
(Angela is genuinely a great science communicator and that video is time well spent if you are interested in this topic.)
-"a SBH could be artificially created by firing a huge number of gamma rays from a spherically converging laser. The idea is to pack so much energy into such a small space that a BH will form."
Otherwise you just have a bomb.
Reactors are much much simpler to pull off, which is why US had the first reactor whole 2.5 years before a nuclear bomb.
It's closely related to the Unruh effect, which is a direct consequence of pure QFT. The Unruh effect describes how an accelerated observer sees a different vacuum from an inertial observer - they see radiation that the inertial observer doesn't.
Hawking radiation is essentially this same effect, except that "acceleration" is replaced by "gravity" (Einstein's equivalence principle.) There's a bit more to it, but that's the basic intuition.
For Hawking radiation to be wrong would require some fundamental changes to GR, QFT, or both.
For example? What I mean by “fundamental” is that we have very strong reasons to believe in the correctness of a prediction, because e.g. it follows mathematically from more than one model (in this case), and doesn’t involve dependence on uncertain physics.
> Wouldnt it be awesome to learn that blackholes, in fact, do not evaporate at all? That would be exciting
These kinds of attitudes don’t seem to me to involve an interest in science. You don’t appear to actually have much understanding or knowledge of what we’re discussing. You’re just looking for a fix.
What form of power and through what principle?
Now as to whether you could use all that power....
First nuclear reactor was 1942, and bomb was 1945.
Once the science is established, we have smart engineers to make a short work out of it.
Fusion energy is really the only counterexample in history, which makes me think we are still missing some crucial physics about how it works, for example in stars. Specifically the particle physics view of how it's reliably triggered with minimal energy.
Also, 25 years to the breakthrough discussed in the article seems like a reasonably good pace.
This is magical thinking. We know how fusion works in great detail. And “reliably triggered with minimal energy” is essentially not a thing, unless by minimal energy you mean something like 10 million times the energy of an air particle at room temperature, for every particle in a reactor.
What we’re trying to do is recreate the conditions at the core of a star - which is powered by gravity due to hundreds of thousands of Earth masses. And since we don’t have the benefit of gravity anything like that, we actually have to make our plasmas significantly hotter than the core of a star. And then contain that somehow, in a way that can be maintained over time despite how neutron radiation will compromise any material used to house it.
The reality is, we still don’t know if usable fusion power is even possible - there’s no guarantee that it is - let alone how to achieve it. The state of the art is orders of magnitude away from even being able to break even and achieve the same power out as was put into the whole system.
That is what I meant, I doubt we really understand what 'powered by gravity' means. You could win a Nobel prize or two by discovering all the details involved here. You would also win a Nobel prize by definitively proving that nothing special happens, you just have high temperatures and high pressures.
The way we are trying to study fusion is like rubbing larger and larger rocks to produce more fire.
[1] https://en.wikipedia.org/wiki/CNO_cycle
[2] https://en.wikipedia.org/wiki/Proton%E2%80%93proton_chain
Quantum physics tells us exactly why high temperatures and pressures are needed, and predicts numerically what values are needed. We have a great deal of confidence in its correctness, especially because classical physics predicted values that were far too high - it’s only with quantum tunneling that we get values that match observations.
> The way we are trying to study fusion is like rubbing larger and larger rocks to produce more fire.
This is an incorrect opinion borne of ignorance of the very well-understood physics involved.
If you're thinking along the lines that if we knew how gravity worked at the quantum scale, we might find some sort of way to achieve fusion under much less extreme conditions, we probably can't entirely rule that out, but there's been many decades of work in that area, so it's seeming pretty unlikely. Also, that has nothing to do with what's happening inside a star.
We know about the need to overcome the electrostatic Coulomb barrier, we know what energies are required to overcome it and have models that predict those energies very accurately, we know how quantum tunneling allows this barrier to be penetrated, etc.
We can even do things like muon-catalyzed fusion, where we substitute muons for electrons in hydrogen atoms, which lowers the Coulomb barrier.
As such, the claims in the comment I originally replied to were just completely wrong.
Also he proposes a few ways that antimatter could be practically used for propulsion, including as a catalyst for fission which seems interesting.