Do matter/anitmatter annihilations have special properties over regular nuclear of conventional (volcanoes, metoerites, etc..) explosions (with potentially orders of magnitude more enrgy involved)? I suppose that as annihilations take much less time than a nuclear chain reaction, volcanic explosion or a meteor impact this is possible.
How do you get around storing antimatter (cheaply)?
Well electron/positron annihilations produce a lot of gamma radiation, useful for the heat it produces as a method of generating electricity but is very bad for human flesh, and can't be useful as a propellant. proton/anti-proton annihilations produce high frequency photons like the former electron/positron interactions but most importantly it produces heavy particles like pions and k-meson among others, although short lived (lets just say most live less than one nanosecond before decaying into other particles), they can be used as a propellant. And I think the easiest way to store anti matter is to make ionic anti-atoms (positrons orbiting anti-protons) and contain them in a container with charged walls. When annihilating them, you get a lot of heat and some propellant. The heat can generate electricity for a charged tube that will propell the other annihilation exhaust out the back of the ship at a high velocity.
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Originally posted by Stoo
Isn't Hawking radiation evidence of negative energy? The theory is that pairs of virtual particles are continuously appearing and cancelling each other out. One of each pair has positive energy, the other negative, giving no problem with conservation of energy. (I'm slightly confused by the conservation of momentum issue though: wouldn't they both go in the same direction?)
If the virtual particle with negative energy falls into a black hole but the postive energy one doesn't, the black hole loses energy (and therefore mass). This energy loss is balanced by the positive energy virtual particle being "emitted" by the black hole as radiation.
Positive energy particles don't make the black hole any larger because ordinary positive particles falling into the black hole lose some energy when they encounter the negative energy virtual particle.
I've no idea if negative energy can be used.
I think what you are decribing is called a 'quantum vacuum' and has root in the Heisenberg uncertainty principal. I just read a book about a particular aspect of this quantum vacuum state that may help think of a way to use the enery of virtual particles... But I don't think it's negative energy. On the event horizon of a black hole, normal physics takes a back seat to the special rules that govern what happens in and around a black hole. But the particles that escape the surface of a black hole have paid their energy price (borrowed energy from the black hole when it gave up some X-Rays) and while sacrificing their partner, they can escape into space as real partlicles. The black hole shrinks ever so slightly. In quadrillions and quadrillions of years, after all stars stop burning and the universe has gone cold, black holes will have evaporated enough to the point where they don't have enough mass to keep the singularity intact. They will explode in a shower of new particles... hmm
Interstellar travel and more, intergalactical ones, will never be possible without dramatical new discoveries in Physic. Traveling at speed faster than the light imply traveling in a different dimension or time.
Even if people are interested in Worms, nobody can said what should arrive to people or object enter in it.
Fondamental science has to move and improve, if we want to have a chance to make space travel.
There is also a possibility that space travel at speed faster than the light are not possible. It may looks as a damnation, but it may also be the best protection against dangerous aliens. The universe is so big, that it's not possible to imagine that we are alone, and the most advanced. And if some creatures are more advanced, it does not means they are more kind and respecteful. Therefore, it's possible if the humankind exist it's because we are protected by the physical laws againsts aliens invaders.
I don't know. They said we couldn't break the sound limit either. And Einstein's theories, however ingenious, are not infallible. Who knows what future discoveries hold.
I don't know. They said we couldn't break the sound limit either. And Einstein's theories, however ingenious, are not infallible. Who knows what future discoveries hold.
Yes who knows ? we don't know if the scientist who will make the next big giant step in fondamental physics, is already born.
Concerning the sound limit theorie was a joke. Each days thousands of meteorites falled in earth and brake the sound limit. Scientists of the time declared that it was impossible, even if it happened in a regular basis around them.
The einstein lightspeed limit is far difficult to break, we don't know if it's possible to break, since some experiments in physics have demonstrates speed higher than the light (if it's not a failure of the experimental process).
Comments
Originally posted by Stoo
Do matter/anitmatter annihilations have special properties over regular nuclear of conventional (volcanoes, metoerites, etc..) explosions (with potentially orders of magnitude more enrgy involved)? I suppose that as annihilations take much less time than a nuclear chain reaction, volcanic explosion or a meteor impact this is possible.
How do you get around storing antimatter (cheaply)?
Well electron/positron annihilations produce a lot of gamma radiation, useful for the heat it produces as a method of generating electricity but is very bad for human flesh, and can't be useful as a propellant. proton/anti-proton annihilations produce high frequency photons like the former electron/positron interactions but most importantly it produces heavy particles like pions and k-meson among others, although short lived (lets just say most live less than one nanosecond before decaying into other particles), they can be used as a propellant. And I think the easiest way to store anti matter is to make ionic anti-atoms (positrons orbiting anti-protons) and contain them in a container with charged walls. When annihilating them, you get a lot of heat and some propellant. The heat can generate electricity for a charged tube that will propell the other annihilation exhaust out the back of the ship at a high velocity.
Originally posted by Stoo
Isn't Hawking radiation evidence of negative energy? The theory is that pairs of virtual particles are continuously appearing and cancelling each other out. One of each pair has positive energy, the other negative, giving no problem with conservation of energy. (I'm slightly confused by the conservation of momentum issue though: wouldn't they both go in the same direction?)
If the virtual particle with negative energy falls into a black hole but the postive energy one doesn't, the black hole loses energy (and therefore mass). This energy loss is balanced by the positive energy virtual particle being "emitted" by the black hole as radiation.
Positive energy particles don't make the black hole any larger because ordinary positive particles falling into the black hole lose some energy when they encounter the negative energy virtual particle.
I've no idea if negative energy can be used.
I think what you are decribing is called a 'quantum vacuum' and has root in the Heisenberg uncertainty principal. I just read a book about a particular aspect of this quantum vacuum state that may help think of a way to use the enery of virtual particles... But I don't think it's negative energy. On the event horizon of a black hole, normal physics takes a back seat to the special rules that govern what happens in and around a black hole. But the particles that escape the surface of a black hole have paid their energy price (borrowed energy from the black hole when it gave up some X-Rays) and while sacrificing their partner, they can escape into space as real partlicles. The black hole shrinks ever so slightly. In quadrillions and quadrillions of years, after all stars stop burning and the universe has gone cold, black holes will have evaporated enough to the point where they don't have enough mass to keep the singularity intact. They will explode in a shower of new particles... hmm
Originally posted by Powerdoc
Interstellar travel and more, intergalactical ones, will never be possible without dramatical new discoveries in Physic. Traveling at speed faster than the light imply traveling in a different dimension or time.
Even if people are interested in Worms, nobody can said what should arrive to people or object enter in it.
Fondamental science has to move and improve, if we want to have a chance to make space travel.
There is also a possibility that space travel at speed faster than the light are not possible. It may looks as a damnation, but it may also be the best protection against dangerous aliens. The universe is so big, that it's not possible to imagine that we are alone, and the most advanced. And if some creatures are more advanced, it does not means they are more kind and respecteful. Therefore, it's possible if the humankind exist it's because we are protected by the physical laws againsts aliens invaders.
I don't know. They said we couldn't break the sound limit either. And Einstein's theories, however ingenious, are not infallible. Who knows what future discoveries hold.
Originally posted by Outsider
I don't know. They said we couldn't break the sound limit either. And Einstein's theories, however ingenious, are not infallible. Who knows what future discoveries hold.
Yes who knows ? we don't know if the scientist who will make the next big giant step in fondamental physics, is already born.
Concerning the sound limit theorie was a joke. Each days thousands of meteorites falled in earth and brake the sound limit. Scientists of the time declared that it was impossible, even if it happened in a regular basis around them.
The einstein lightspeed limit is far difficult to break, we don't know if it's possible to break, since some experiments in physics have demonstrates speed higher than the light (if it's not a failure of the experimental process).