if we use Antimatter as method of propulsion is it possible to reach speed of light ?

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    $\begingroup$ Nothing that has mass can reach speed of light. No matter what propulsion you use. $\endgroup$
    – SF.
    May 28, 2018 at 2:20

1 Answer 1



Accelerating mass to the speed of light requires infinite energy. A matter-antimatter reaction releases a huge amount of energy, but $huge \neq \infty$, not even close.

On the other hand, if you want to accelerate something without mass to the speed of light, you don't need anything fancy such as antimatter. Just turn on a flashlight.

  • 3
    $\begingroup$ Photons are not accelerated to the speed of light, they have that speed when they are generated. It is not possible to accelerate or deccelerate a photon. $\endgroup$
    – Uwe
    May 28, 2018 at 8:39
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    $\begingroup$ Extending your answer, I would mention that 1 tons of matter-antimatter mix accelerating 1 tons of payload would be close to the speed of the light (around 200000 km/s would be reachable, $c$ is around 300000 km/s), thus I doubt the "not even close" part from a theoretical view. I agree it from a practical/engineering view (we are not even close to produce even similar). $\endgroup$
    – peterh
    May 28, 2018 at 10:44
  • $\begingroup$ @peterh Is that assuming 100% efficiency in converting the energy release into kinetic energy? $\endgroup$ May 28, 2018 at 14:20
  • $\begingroup$ @RussellBorogove Well, considering the temperature of baryonic matter annihillation (in order of some billions K), I think we could assume a nearly 100% thermodynamical effectivity. Well, I also ignored the neutrino losses (estimated around 60%). But I think the largest problem with it is not this, the problem is that we didn't create a single milligram of antimatter in the whole human history. $\endgroup$
    – peterh
    May 28, 2018 at 15:06
  • $\begingroup$ "I think we could assume a nearly 100% thermodynamical effectivity" .... ohhh....kay? Now, direct it. $\endgroup$ May 28, 2018 at 16:44

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