Positrons cost $25M/mg and antihydrogen costs $62.5B/mg.
An interstellar trip to Alpha Centauri using antihydrogen-hydrogen annihilation reactions would cost more than 50 years of the entire economic output of the planet (as of 2016) just for the fuel. Since we need a large portion of that economic output for basic survival needs, there will be no antimatter rockets built any time soon.
As far as I am aware, we currently lack the capability to create a singularity massive enough to persist long enough to observe as a black hole. But it is possible that we might be able to locate a primordial black hole near enough to build a propulsion system around it, or even trap one as it passes through Earth. This would, of course, require that primordial black holes exist, and that they emit Hawking radiation.
Yes, for now it is purely speculation. Anything beyond chemical-energy rockets is speculation until we actually demo the technology in a real spacecraft. If you launched today, bound for Alpha Centauri, the best you could do is drop fusion bombs behind your vessel until you get to about 0.08c, turn around at some point and throw fusion bombs in your path to decelerate, and be prepared to arrive a long, long time from now.
An interstellar trip to Alpha Centauri using antihydrogen-hydrogen annihilation reactions would cost more than 50 years of the entire economic output of the planet (as of 2016) just for the fuel. Since we need a large portion of that economic output for basic survival needs, there will be no antimatter rockets built any time soon.
As far as I am aware, we currently lack the capability to create a singularity massive enough to persist long enough to observe as a black hole. But it is possible that we might be able to locate a primordial black hole near enough to build a propulsion system around it, or even trap one as it passes through Earth. This would, of course, require that primordial black holes exist, and that they emit Hawking radiation.
Yes, for now it is purely speculation. Anything beyond chemical-energy rockets is speculation until we actually demo the technology in a real spacecraft. If you launched today, bound for Alpha Centauri, the best you could do is drop fusion bombs behind your vessel until you get to about 0.08c, turn around at some point and throw fusion bombs in your path to decelerate, and be prepared to arrive a long, long time from now.