[adrianN]

The most realistic sci-fi engines are nuclear pulse engines where you ride the shockwaves of thousands of fusion bombs to reach a few percent of the speed of light. Those we could probably build right now if we were willing to spend the money. Replacing the fusion bombs with antimatter bombs would be a nice improvement for the basic design

[gpderetta]

I think the more "practical" idea is to replace the fission stage of a fusion bomb with antimatter annihilation.

[gpderetta]

i.e.: https://en.wikipedia.org/wiki/Antimatter-catalyzed_nuclear_p..., although it doesn't really replace the primary, just decreases the required quantity.

[mr_mitm]

Is there a way to slow down using fusion bombs? Even if you manage to bring thousands of fusion bombs with you? Sounds like this is only a sensible approach for sending probes, which will then zip by their target at huge speeds.

[xavxav]

you just need to speed up in the opposite direction by flipping around and firing bombs on the other side.

[ajuc]

Which means if we get discovered by an alien probe it will look a lot like getting on the wrong end of a nuclear war.

I remember there was a quote from some sci-fi universe that there's "no such thing as an unarmed space ship".

[arethuza]

I believe that is the "Kzinti Lesson" from Larry Niven:

"A reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive."

https://tvtropes.org/pmwiki/pmwiki.php/Main/WeaponizedExhaus...

[froh42]

If you can get any kind of spaceship up to speeds to reach other stars within reasonable time - you've got an amazing weapon. Just ram into something at full speed. Ok, if you have enough energy to correct course to aim, only.

[RangerScience]

It’s more than twice(1) as easy to make a rocket-propelled bullet than a rocket-propelled vehicle!

1) It’d be exactly twice as easy but for Tsiolkovsky!

[emmavis]

Thanks for explanation!

[nrhrjrjrjtntbt]

How do you do that and not die?

[ajuc]

Long stick and radiation shield between you and the bombs