| ▲ | csense 4 hours 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? |
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| ▲ | pfdietz 3 hours ago | parent | next [-] |
| The 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 |
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| ▲ | amelius 4 hours ago | parent | prev | next [-] |
| > 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. |
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| ▲ | teiferer 3 hours ago | parent | next [-] | | > If you're ok with the looming threat of total annihilation. Don't you have that problem with any energy-dense fuel? It's just that it doesn get more dense than that, so you can be very space and weight efficient. It's like everybody saying that a hydrogen car is a rolling bomb because of the energy stored in the hydrogen. Well, sure, but gasonline has just as much energy stored. Which is the whole point of fuel. To store energy. It's not like you are bringing 100x as much energy with you just because it's hydrogen. So that doesn't make an ICE car any less of a bomb... | | |
| ▲ | antonvs 3 hours ago | parent | next [-] | | Antimatter is a completely different story. The difference is that antimatter annihilates with any normal matter that it comes into contact with. This means you can't just put it in a tank, the way you can with hydrogen. You can't e.g. combine it with some metal to make a metal hydride to make it safer to store, the way you can with hydrogen. At an absolute minimum, you need extremely strong magnetic confinement and an extremely hard vacuum. And even then, you're going to get collisions with stray atoms and annihilation events which release gamma rays and other radiation products - although shielding is probably the least of your worries in this scenario. A typical research lab at a university or large corporation can't make a vacuum strong enough to store even tiny quantities of antimatter for more than a few minutes, and they can't produce the magnetic confinement strength required to store macro quantities of it, either. So the question with an antimatter-powered car is not if it's going to destroy the surrounding region and bathe it in hard radiation, but how many milliseconds (or less) it will take before that inevitably happens. But probably luckily for us, this is all moot, because we have no way of producing enough antimatter for this to be an issue. If all the antimatter that's ever been created by humans annihilated simultaneously, only scientists monitoring their instruments closely enough would notice, because it's such a microscopic amount. Edit: for perspective, you'd need about 7 billion times the 92 antiprotons transported in the truck in the story to produce the energy produced by a single grain of gunpowder. | | |
| ▲ | micw 2 hours ago | parent [-] | | You can easily put it into an antimatter tank ;-) | | |
| ▲ | antonvs 2 hours ago | parent [-] | | Only if you wear antimatter gloves while doing it. Also, now your tank is just fuel as well. |
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| ▲ | Tadpole9181 3 hours ago | parent | prev | next [-] | | Surely you understand there's a difference? Liquid gasoline does not spontaneously explode like an action movie. You can put a match in the fuel tank and (presuming infinite oxygen availability) it'd just start a small fire. Heck, may even just give a little puff and then put out the match. Antimatter in any sufficient fuel quantity, the moment it breaks confinement, will completely annihilate and release ALL it's energy in a single moment, setting off a chain reaction to the remaining antimatter. It's like sitting on an armed nuclear bomb, where you rely on electrified, highly sophisticated containment equipment never failing a single time for months to years... In a radiation-heavy environment known for causing sophisticated electronics to have errors. And, yes, hydrogen cars were looked at critically because of the perception they can Hindenburg (I'm unsure if it's true or not). Which is a good example because you don't particularly see any hydrogen blimps anymore - we made them illegal because they're dangerous. | | |
| ▲ | SoftTalker an hour ago | parent [-] | | Any compressed gas fuel is inherently dangerous. There's a video of a CNG-fueled bus falling off a lift and sending a fireball through the maintenance facility. Batteries have some of these same risks: they store a lot of energy and it can be released very quickly under the wrong circumstances. | | |
| ▲ | Tadpole9181 31 minutes ago | parent [-] | | Which is why we generally don't use highly volatile fuels in vehicles, like I just said? And, no, batteries can have outbursts but they're nowhere near as catastrophic as compressed, explosive gases or an antimatter bomb. |
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| ▲ | im3w1l 3 hours ago | parent | prev [-] | | Volatility and energy content are not necessarily related. | | |
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| ▲ | crooked-v 4 hours ago | parent | prev | next [-] | | If you're on a spacecraft you're sitting on a tank of rocket fuel anyway. It's the same problem, just slightly less total. | | |
| ▲ | sigmoid10 3 hours ago | parent | next [-] | | Average 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 3 hours ago | parent | prev | next [-] | | Antimatter 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. | | |
| ▲ | adrian_b 19 minutes ago | parent | next [-] | | Nuclear energy is limited to a little less than 1% of the energy release possible with antimatter, per mass. The practical limit for nuclear energy is about 5 to 10 times less than that, because the theoretical limit corresponds to the transmutation of hydrogen into iron, coupled with the capture of the entire energy, which will not be achievable any time soon. But there is an essential difference between nuclear energy and antimatter energy. Nuclear energy is stored in our environment and you just have to exploit it. Antimatter energy is a form of energy storage, so you need some other form of energy to make antimatter. The energy efficiency of making antimatter is many orders of magnitude worse than the factor of less than 100 that exists between nuclear energy and antimatter energy and the mass of the confinement device needed for storing antimatter is also orders of magnitude greater than the mass of the stored antimatter. For now, there is absolutely no hope of ever using antimatter in practice for storing energy. Such a thing could be enabled only if some technologies that we cannot imagine would be invented. Despite the great technological progress of the last couple of centuries, it is hard to say that there have been many inventions that have never been imagined before. After all, already 3 millennia ago the god Hephaestus did his metal smith work with the help of intelligent artificial robots. | |
| ▲ | ComputerGuru 3 hours ago | parent | prev [-] | | You can carry exactly (or roughly) as much energy in the form of antimatter as you would energy in the form of fuel. | | |
| ▲ | amelius 2 hours ago | parent [-] | | The problem is that a tiny leak will eat away your spacecraft, thereby making the situation worse. |
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| ▲ | amelius 3 hours ago | parent | prev [-] | | Except rocket fuel lines are often leaking, and the most common cause of launch delays. With antimatter the tiniest leak will annihilate your ship. |
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| ▲ | boxingdog an hour ago | parent | prev [-] | | [dead] |
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| ▲ | d_silin 4 hours ago | parent | prev | next [-] |
| Very tough engineering problem.
Amount transported is 92 atoms. A mole (1 gram) of anti-hydrogen is 6.23x10^23 atoms. |
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| ▲ | wiredfool 4 hours ago | parent [-] | | When 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 4 hours ago | parent [-] | | If 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. | | |
| ▲ | TheOtherHobbes an hour ago | parent | next [-] | | Interstellar 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. | | |
| ▲ | d_silin 23 minutes ago | parent | next [-] | | You 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). | |
| ▲ | inetknght 25 minutes ago | parent | prev [-] | | Not with that attitude, we're not! |
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| ▲ | JumpCrisscross 3 hours ago | parent | prev [-] | | > 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. |
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| ▲ | bovermyer 3 hours ago | parent | prev | next [-] |
| From 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. |
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| ▲ | pfdietz 3 hours ago | parent | next [-] | | The big advantage of nuclear weapons is they are very cheap per unit of energy yield. Bang for the buck, if you will. Antimatter production is so inefficient that they will be much more expensive per unit energy yield. | | |
| ▲ | garciasn 2 hours ago | parent [-] | | There are a lot of completely random statements about how much a gram costs floating around out there. Anywhere from $60T to $3,000T. According to, Michael Doser, a prominent particle physicist at CERN, "one 100th of a nanogram [of antimatter] costs as much as one kilogram of gold." S: https://www.abc.net.au/news/science/2023-02-19/antimatter-fa... | | |
| ▲ | thaumasiotes an hour ago | parent [-] | | > According to, Michael Doser, a prominent particle physicist at CERN, "one 100th of a nanogram [of antimatter] costs as much as one kilogram of gold." Those aren't comparable costs. The cost given for antimatter is the cost of producing it from nothing. The cost given for gold is the market price of buying gold that already exists. Consider the cost of producing one kilogram of gold from nothing. (Consider also the cost of ownership. Gold has a higher-than-average cost of ownership; you have to provide security or it will be stolen. Antimatter's cost of ownership is far, far beyond that.) |
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| ▲ | ReptileMan 3 hours ago | parent | prev [-] | | Not that great. Chances are you will destroy your country before you destroy some other. | | |
| ▲ | mastersummoner 3 hours ago | parent | next [-] | | That's just an engineering problem as well. | |
| ▲ | fragmede 2 hours ago | parent | prev [-] | | Not 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 2 hours ago | parent | next [-] | | Antimatter 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. | |
| ▲ | drfloyd51 2 hours ago | parent | prev [-] | | But they were wrong and we were right! |
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| ▲ | yibg 4 hours ago | parent | prev | next [-] |
| Not 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? |
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| ▲ | jjmarr 4 hours ago | parent | next [-] | | > 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/S266620272... | |
| ▲ | daveguy 3 hours ago | parent | prev | next [-] | | The always excellent PBS Space Time recently did an episode on antimatter drives: https://m.youtube.com/watch?v=eA4X9P98ess | |
| ▲ | 3 hours ago | parent | prev | next [-] | | [deleted] | |
| ▲ | goda90 4 hours ago | parent | prev | next [-] | | Use the antimatter as an electricity source to power ion thrusters, maybe? | |
| ▲ | BiraIgnacio 3 hours ago | parent | prev [-] | | my 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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| ▲ | adrianN 4 hours ago | parent | prev | next [-] |
| Black holes are good star ship engines because they turn everything into Hawking radiation. |
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| ▲ | 2 hours ago | parent | prev [-] |
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