3 ms·

There's always many considerations. Energy density, stability, what kind of energy can you convert it to, can it be directed easily, how hard is it to store etc

There's always many considerations. Energy density, stability, what kind of energy can you convert it to, can it be directed easily, how hard is it to store etc...

whatshisface 5y ago
Antimatter's reputation for being incredibly difficult to store comes from the fact that it's produced as individual particles. A superconducting antimatter hockey puck would be much easier to store than a cloud of antiprotons of the same mass. And yeah, you'll need a way to build gamma ray mirrors before antimatter reactions will push you in any direction (the energy comes flying out isotropically and we can't presently do anything to stop or direct it), but we can cross that parsec when we come to it. :-)
- ashtonkem 5y ago
  Gamma ray mirrors sound like they’d be extremely useful for nuclear power too.
- 8note 5y ago
  Superconductors pretty notoriously need to be kept cold, which adds another difficulty of cooling the antimatter without touching it
  - whatshisface 5y ago
    If it was surrounded by a cold mass that it could radiate photons to across a vacuum, its equilibrium temperature would be that of its container.
  - kadoban 5y ago
    For now. By the time anyone could even possibly create enough antimatter to matter (heh), critical temperatures should be much higher. The record is broken fairly commonly.
- human 5y ago
  I would be so nervous to be in the middle of space with an hockey puck of antimatter.
  - yccs27 5y ago
    I guess I'd be just as nervous in space with thousands of tonnes of explosive propellant. Spaceflight always operates on the very edge of what's possible, not of what's safe.
- coldacid 5y ago
  I think that's what the dilithium crystals are for. ;D
- jjk166 5y ago
  Presumably antimatter would be your energy source, but not your propellant. The gamma rays from a small number of annihilations would heat up a much larger amount of normal matter. At least for the first generation, you likely also wouldn't be using antimatter as the main source of energy, but rather as a method of initiating some other reaction. For example where in a conventional fission reaction you get a relatively clean split of a nucleus into two halves plus a few extra neutrons to drive a chain reaction, an antiproton will blast apart such a nucleus like a billiard break, allowing fission reactions with much less than a conventional critical mass. A quick burst of positrons hitting the surface of some lithium deuteride would be able to replace a fission primary and make a pure-fusion explosion. Either of these options could be used as either incredibly low-mass nukes for an orion drive or as a light weight reactor for a more conventional nuclear propulsion method. While about 600 times less energy dense than pure antimatter, you're still talking 10 million times better energy density than our best current rocket fuels, while using several orders of magnitude less antimatter.

There's always many considerations. Energy density, stability, what kind of energy can you convert it to, can it be directed easily, how hard is it to store etc...

whatshisface 5y ago

Antimatter's reputation for being incredibly difficult to store comes from the fact that it's produced as individual particles. A superconducting antimatter hockey puck would be much easier to store than a cloud of antiprotons of the same mass. And yeah, you'll need a way to build gamma ray mirrors before antimatter reactions will push you in any direction (the energy comes flying out isotropically and we can't presently do anything to stop or direct it), but we can cross that parsec when we come to it. :-)

ashtonkem 5y ago
Gamma ray mirrors sound like they’d be extremely useful for nuclear power too.
8note 5y ago
Superconductors pretty notoriously need to be kept cold, which adds another difficulty of cooling the antimatter without touching it
- whatshisface 5y ago
  If it was surrounded by a cold mass that it could radiate photons to across a vacuum, its equilibrium temperature would be that of its container.
- kadoban 5y ago
  For now. By the time anyone could even possibly create enough antimatter to matter (heh), critical temperatures should be much higher. The record is broken fairly commonly.
human 5y ago
I would be so nervous to be in the middle of space with an hockey puck of antimatter.
- yccs27 5y ago
  I guess I'd be just as nervous in space with thousands of tonnes of explosive propellant. Spaceflight always operates on the very edge of what's possible, not of what's safe.
coldacid 5y ago
I think that's what the dilithium crystals are for. ;D
jjk166 5y ago
Presumably antimatter would be your energy source, but not your propellant. The gamma rays from a small number of annihilations would heat up a much larger amount of normal matter. At least for the first generation, you likely also wouldn't be using antimatter as the main source of energy, but rather as a method of initiating some other reaction. For example where in a conventional fission reaction you get a relatively clean split of a nucleus into two halves plus a few extra neutrons to drive a chain reaction, an antiproton will blast apart such a nucleus like a billiard break, allowing fission reactions with much less than a conventional critical mass. A quick burst of positrons hitting the surface of some lithium deuteride would be able to replace a fission primary and make a pure-fusion explosion. Either of these options could be used as either incredibly low-mass nukes for an orion drive or as a light weight reactor for a more conventional nuclear propulsion method. While about 600 times less energy dense than pure antimatter, you're still talking 10 million times better energy density than our best current rocket fuels, while using several orders of magnitude less antimatter.