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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 htt
by modeless 11mo ago
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://news.ycombinator.com/item?id=46073414
- p2detar 11mo agoThere was also a great episode on antimatter engines recently by PBS Space Time. https://www.youtube.com/watch?v=eA4X9P98ess https://www.youtube.com/watch?v=eA4X9P98ess
- IsTom 11mo agoIf you can electromagnetically trap enough antimatter to use it as fuel you could as well trap a miniature charged black hole that can be fed regular matter to produce power, which skips the whole inefficient part of making antimatter.
- DennisP 11mo agoDepends. Do we know how to obtain a miniature black hole?
- octaane 11mo agoThere have been several proposals. This paper proposes a feasable mechanism[1]: -"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." 1. https://arxiv.org/abs/0908.1803 https://arxiv.org/abs/0908.1803
- piannucci 11mo agoThere’s a recent paper on the formation of such a “kugelblitz”; it’s argued to be unfeasible. https://arxiv.org/abs/2405.02389 https://arxiv.org/abs/2405.02389
- randallsquared 11mo agoThe biggest problem is that if you're creating it with lasers, you're only going to get the energy out that you put in. You really want to be able to feed it matter, which would effectively make it an anything-to-gamma-radiation converter, which means you have to feed it quite a lot of matter, against the radiation pressure of all that energy coming out. The paper mentioned assumes a worst case of not being able to feed the black hole at all, but doesn't (in my skim) address the fact that this means you have to put in all the energy you'll be using for the lifetime of the black hole at the creation of it, which seems significantly more outrageously infeasible than the bare necessity of creating a black hole at all.
- jojobas 11mo agoDoes anyone address the fact that a black hole will be falling towards the center of the earth at 1g? How do you handle a black hole?
- impossiblefork 11mo agoMiniature black holes would just evaporate. Antimatter wouldn't.
- fooker 11mo agoNot before efficiently converting a large amount of mass into usable energy.
- GenerWork 11mo agoHow could we harness this energy and make it usable?
- einpoklum 11mo agoYou could pen a carefully-worded a letter of demands and send it to some Billionaire? A bit on the risky side, but - hey, you only live once etc.
- fooker 11mo agoIf I knew that, I'd probably have more important things to do than comment it here.
- remarkEon 11mo agoYou use it to boil water.
- 0-_-0 11mo agoIt's almost a meme at this point
- fooker 11mo agoThe real question is if we'll get back hole or antimatter powered steam engines before GTA 6
- Symmetry 11mo agoYou can even dissolve the uranium in the water and use the same substance for both fuel and propellant and so capable of reaching far higher temperatures than those that would cause any engine to melt. https://en.wikipedia.org/wiki/Nuclear_salt-water_rocket https://en.wikipedia.org/wiki/Nuclear_salt-water_rocket
- vkou 11mo ago> a miniature charged black hole that can be fed regular matter to produce power, What form of power and through what principle?
- andrewflnr 11mo agoHawking radiation, I think. Yes, this is at best speculatively feasible.
- manphone 11mo agoProbably more like a water wheel - matter spinning around the hole can be accelerated.
- Qem 11mo agoA spacecraft carrying a blackhole as propulsion means probably would have poor power to weight ratio.
- idiotsecant 11mo agoNot at all. It would have one of the best power to weight ratios possible. Now as to whether you could use all that power....
- galacticaactual 11mo agoThey made a movie about this. It didn’t end so well for the crew.
- gavinmckenzie 11mo agoI admit to invoking the phrase “Where we’re going, we won’t need eyes to see” at least once a year when something feels like it’s going horribly wrong.
- m4rtink 11mo agoBut it was one hell of a ride! ;-)
- dmead 11mo agoThe romulan empire does this.
- antonvs 11mo agoWe know how to make antimatter and have actually done it. We have no realistic way to obtain a black hole of any size.
- teamonkey 11mo agoFor those who are time-rich and knowledge-poor: https://youtube.com/watch?v=i6jMnz6nlkw 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.)
- doug713705 11mo agoYou can skip the first 42 minutes that are about how bad is an article titled "how antimatter space craft will work". This part is absolutely boring as hell !
- einpoklum 11mo agoWhat's the key point regarding how we would get a bajillion times more anti-matter than we can now generate, and without expending all the energy we now expend on getting it?
- modeless 11mo agoHis point seems to be that we haven't yet seriously tried optimizing for energy efficiency of producing antimatter. It's a call to action. If we actually tried it's plausible that we could get to a level that, while still fantastically inefficient in an absolute sense, would still be worthwhile for spaceflight propulsion, where energy density is vitally important. As far as I know, antimatter is the most energy dense fuel possible in known physics by many orders of magnitude. Also he proposes a few ways that antimatter could be practically used for propulsion, including as a catalyst for fission which seems interesting.
- pfdietz 11mo agoBefore we get too excited, this current "breakthrough" is making less than 1 antihydrogen atom per second. This corresponds to a delivered annihilation power of less than 1 nanowatt.
- fooker 11mo agoNeutrons were first definitively observed in 1932. 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.
- fsh 11mo agoThe antiproton decelerator at CERN has been operational for 25 years, and they have plenty of smart engineers there. Unlike in the 1940s, the underlying physics has been well understood for many decades. I would argue that nuclear fission is the counter example that happens to be surprisingly easy to do.
- fooker 11mo agoCERN is trying to do fundamental physics, not trying to weaponize antimatter. If/when it comes to that, the pace will pick up. Also, 25 years to the breakthrough discussed in the article seems like a reasonably good pace.
- fsh 11mo agoAll experiments at the AD are strongly limited by the low rates. If there was a straightforward way to improve this by many orders of magnitude, they would have done it a long time ago.
- antonvs 11mo ago> Fusion energy is really the only counterexample in history, which makes me think we are still missing some crucial physics about how it works 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.