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From a layman's point of view antimatter seems like an ideal spacecraft fuel. It's as energy dense as E = mc^2 allows, and if you have infrastructure to make i
by csense 6mo ago
From a layman's point of view antimatter seems like an ideal spacecraft fuel. It's as energy dense as E = mc^2 allows, and if you have infrastructure to make it, the only input you need to produce it is electricity.
Being able to transport it seems like an important piece of that puzzle.
Production and storage would need to be scaled by many orders of magnitude, but that's merely an engineering problem...right?
- scotty79 6mo agoTo propel things in space you don't need as much energy as you need momentum. With antimatter you just have momentum of the photons that were produced in the annihilation. I don't know if that's the best way of getting momentum. Might be.
- d_silin 6mo agoVery tough engineering problem. Amount transported is 92 atoms. A mole (1 gram) of anti-hydrogen is 6.23x10^23 atoms.
- wiredfool 6mo agoWhen I visited CERN, they mentioned that there were some large number of protons in the ring at a time, and the runs would last a significant amount of wall clock time. (Don’t remember the exact numbers, but I think it was like 10^19 atoms of H, and days of wall clock) The upshot was, it was likely that less than a mol of hydrogen had been run through the ring.
- d_silin 6mo agoIf humanity doesn't perish in the next hundred year and masters interplanetary spaceflight, antimatter drive is the logical next step in propulsion after fusion. Interstellar spaceflight will become (barely) feasible once spaceships can reach velocity between 0.02 to 0.1c are possible. Even assuming non-100% conversion efficiency, antimatter has enough energy density to provide this capability.
- JumpCrisscross 6mo ago> antimatter drive is the logical next step in propulsion after fusion Maybe. Beamed propulsion makes a hell of a lot more sense in the solar system.
- TheOtherHobbes 6mo agoInterstellar flight is a new physics problem, not a smash-the-tiny-rocks-together-to-make-bigger-bang problem. We're not going anywhere without a revolution in our understanding of the universe.
- inetknght 6mo agoNot with that attitude, we're not!
- d_silin 6mo agoYou don't need new physics for interstellar spaceflight - 16 km/s of dV is enough. you don't even need to go that much faster to slowly spread among the stars. There are a lot of smaller bodies all the way from Sun to Alpha Centauri. As long as you hop between them within reasonable time in a few thousand years you can become a true interstellar civilization, while going at much-slower-than-light velocity (similar to Polynesian colonization of Pacific).
- BobaFloutist 6mo agoMy memory is that 1g of constant acceleration grants sufficient relativity to make it to the edge of the known universe in a current human lifespan. Now, it's true, there's some slight issues such as radiation, food storage/production, psychological effects, and any random space rocks obliterating your craft, all of which could reasonably turn out to be enough to make it not work. We also don't have a fuel source that can provide 1g of constant acceleration for 80 years for a reasonably sized space ship, though again my memory is that nothing prohibits it from a physics perspective (this is where my knowledge/understanding get prohibitively poor. I'm not sure how the math works if you stick a thousand ion drives to a spaceship that's already in space or if you just need a huge snifter of compressed hydrogen or if you can just use nuclear propulsion but I'm pretty sure that antimatter would do it, if you could bring yourself to waste the money. But maybe we don't have a plausible way to contain it so what do I know). Maybe I'm remembering wrong, or maybe I glossed over what's currently considered a physics, rather than engineering/economic/materials science problem, but that's what it looked like last I checked.
- adrianN 6mo agoBlack holes are good star ship engines because they turn everything into Hawking radiation.
- throwaway894345 6mo agoCan you elaborate? Why is HR useful for starship engines?
- yibg 6mo agoNot familiar with the subject so genuine question. HOW would antimatter be used as fuel? There is energy released in matter antimatter annihilation, but where would the force to move a spacecraft come from?
- goda90 6mo agoUse the antimatter as an electricity source to power ion thrusters, maybe?
- jjmarr 6mo ago> Various antiproton-powered rocket systems have been proposed. All of which rely on the particles released to supply direct thrust or to heat a working fluid by interparticle collisions or by heating a solid core first [14]. There is also the possibility to use the heated working fluid to generate electricity for electric propulsion systems [14]. > Following Fig. 9, beam core and plasma core configurations can produce direct thrust by directing the charged particles produced into an exhaust beam using a magnetic nozzle. Gas core systems use the energy released from the reaction to heat a gas that is exhausted for thrust. Finally, solid core configuration heats a metal core like Tungsten that acts as a heat exchanger to a propellant that is then exhausted from a regular nozzle. Not the same paper, but goes into more detail. https://www.sciencedirect.com/science/article/pii/S2666202724004518 https://www.sciencedirect.com/science/article/pii/S266620272...
- daveguy 6mo agoThe always excellent PBS Space Time recently did an episode on antimatter drives: https://m.youtube.com/watch?v=eA4X9P98ess https://m.youtube.com/watch?v=eA4X9P98ess
- BiraIgnacio 6mo agomy absolutely-non-expert guess is that it would work much like any other fuel? Combine with matter, get a lot of head out of it and use that in the best way we know.
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- amelius 6mo ago> ideal spacecraft fuel If you're ok with the looming threat of total annihilation. I suppose at least it will kill you faster than your neurons can communicate so you wouldn't even notice.
- crooked-v 6mo agoIf you're on a spacecraft you're sitting on a tank of rocket fuel anyway. It's the same problem, just slightly less total.
- amelius 6mo agoExcept rocket fuel lines are often leaking, and the most common cause of launch delays. With antimatter the tiniest leak will annihilate your ship.
- sigmoid10 6mo agoAverage human threat perceptions simply aren't useful here. People will also make wild assumptions about what kind of catastrophic thing could happen in aviation and then happily enter their car to drive somewhere without a thought in the world. In fact noone thought about designing gasoline fuel tanks in a safe way before we had cars. Not even really until people started burning. If we're already thinking about transporting antimatter safely today, this kind of technology will probably have an even better track record than planes.
- queuebert 6mo agoAntimatter reactions are about a million times more powerful than conventional combustion. They surpass even nuclear explosions in energy release. That means even a small mishap becomes a large mishap.
- AngryData 6mo agoYeah but when you are talking about energy levels in the nuclear bomb range, the threat to the passenger stops going up. If im in a craft with 1 Hiroshima bomb of energy and another guy is in one with a million tsar bombs worth of energy, we would both be obliterated before we knew anything was wrong no matter how small of a mishap.
- bovermyer 6mo agoFrom a layman's point of view, I'm more interested in antimatter's potential as a weapon. Not necessarily because I want to use it, but because I have a vague idea of what it's capable of, and what that would mean in the hands of certain groups capable of producing it.
- ReptileMan 6mo agoNot that great. Chances are you will destroy your country before you destroy some other.
- mastersummoner 6mo agoThat's just an engineering problem as well.
- everforward 6mo agoIt’s a fundamentally different and riskier paradigm. Nuclear weapons at rest are inert, and can even be disarmed. If the lock falls off the gate at the compound, the nukes won’t spontaneously explode. Antimatter is always “armed” and is only rendered safe by containment. If containment fails, it explodes. It’s more like keeping a massive stockpile of fluorine, but somehow worse and harder to contain.
- fragmede 6mo agoNot to be dramatic, but wouldn't that level of destruction threaten all life on Earth? After the immediate destruction of the first county, extreme climate change would cause the same kind of problems as nuclear winter would, no?
- TheOtherHobbes 6mo agoAntimatter bombs are not a realistic technology. Aside from the unsolved technical issues - many, and fatal - no country has the GDP needed to make 1g of antimatter, which would make an explosion around 40kT. We can't afford to blow up ourselves that way. There are plenty of other ways we can afford, so antimatter isn't top of anyone's worries.
- pfdietz 6mo agoThe confinement scheme used here is likely a Penning Trap. Such devices are limited in the amount of antimatter they can store by the Brillouin limit. The energy stored will be no more than the magnetic energy of the field of the trap, and so much less than the explosive yield of a mass of TNT (say) equal to the mass of the trap. https://en.wikipedia.org/wiki/Non-neutral_plasma https://en.wikipedia.org/wiki/Non-neutral_plasma
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- estimator7292 6mo agoI don't like antimatter because it's the most volatile fuel possible. If power is ever interrupted for any reason for any amount of time, the entire mass explodes. A slightly less insane fuel source is a micro black hole. Drag a tiny black hole behind your ship and drip-feed it any kind of mass you come across. You still get >90% mass-energy efficiency which is far beyond anything else we know of. Besides, one of the big problems with antimatter is that it's a battery, not a fuel source. We must first collect the unimaginable amount of energy and then process it into antimatter one particle at a time. If you build a ton of factories around a star you can get meaningful production. But a black hole drive can suck up interstellar gas or any asteroids you come across. Matter is easy to get. Don't ask where the micro black hole comes from.
- andrewflnr 6mo agoBlack holes have similar problems to antimatter. A micro black hole is pretty close to an ongoing antimatter explosion in terms of effects on its surroundings. If any part of your shielding fails, it irradiates you or melts you. Their radiation increases as they get smaller, and if not fed they're always getting smaller, until they "explode" (yes, but even more so) and disappear. So you still have the problem that if you don't maintain it just right, it will annihilate your ship. So, "less insane" is dubious IMO. (Still my favorite starship idea, though.)
- ant6n 6mo agoHow heavy is the micro black hole? How do you “drag” it?