Can FTL Travel Be Used as a Weapon in Sci-Fi?

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I'm just curious, there are a lot of "warp speed" and "Faster than Light" and "Hyperspace" things in movies and books. It seems to me that such technology would be somewhat devastating if not policed or controlled properly.

For example - the Death Star in star wars. It is a technology to destroy planets, but I can't help but think that, were the empire to fly an (empty) star destroyer into a planet at light speed, it would surely destroy said planet utterly, with no prior warning and not colossal, ominous moon with an easily accessed "off" switch.

Does anyone know of any movies or books which feature using "warp speed" as a weapon, rather than simply as a means of travel?
 
on Phys.org
You don't need FTL, all you really need is http://www.projectrho.com/public_html/rocket/reactionlessdrive.php
And even if you, the science fiction author, hand-waved one into existence for your SF novel, you've still got problems.

A working reactionless drive could turn a cheap solar power array and a brick into civilization destroying weapon of ubermassive destruction.

Burnside's Advice is Friends Don't Let Friends Use Reactionless Drives In Their Universes.
 
some bloke said:
I'm just curious, there are a lot of "warp speed" and "Faster than Light" and "Hyperspace" things in movies and books. It seems to me that such technology would be somewhat devastating if not policed or controlled properly.

For example - the Death Star in star wars. It is a technology to destroy planets, but I can't help but think that, were the empire to fly an (empty) star destroyer into a planet at light speed, it would surely destroy said planet utterly, with no prior warning and not colossal, ominous moon with an easily accessed "off" switch.

Does anyone know of any movies or books which feature using "warp speed" as a weapon, rather than simply as a means of travel?
In "The Last Jedi", The Laura Dern character used a ship in hyperdrive to punch through a star destroyer.
But, I think maybe one reason you couldn't use such a method to destroy a planet is that, assuming a FTL drive assumes that you found a way around the infinite energy requirement for reaching light speed. In other words, you've gotten the energy you need to expend to reach FTL down to something your ship could reasonably produce.
But that, in turn, limits the energy your ship traveling at FTL would have or could release in a collision.
A ship traveling at FTL would not have anywhere near the energy of a ship traveling near the speed of light, but got there by conventional propulsion.
 
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Depending on the FTL, it may not be able to be a weapon. Any method where the ship is 'outside' our universe and not interacting with it would preclude a direct form of attack, and when the ship returns to our universe, you are back to normal e=mc2 attacks. But an Alcubierre drive would work as a weapon (okay, could work, it's theoretical, obviously so this is speculative) and the Owner Trilogy by Neal Asher has such an example.

Wormholes are also used as weapons in many stories, with 'wormhole taps' placing one end into the interior of a star and the other end being used as a stellar energy fire hose. Dropping explosive devices into stars is similar, and Gary Gibson's Shoal Sequence has weapons like this to send stars nova.

As with most things, FTL could be used for good and for bad...but for bad makes for some great plot lines!
 
some bloke said:
Does anyone know of any movies or books which feature using "warp speed" as a weapon, rather than simply as a means of travel?

In "Singularity Sky" Charles Stross suggests that the violation of causality resulting from FTL travel could be used as a weapon.
 
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DrStupid said:
In "Singularity Sky" Charles Stross suggests that the violation of causality resulting from FTL travel could be used as a weapon.

I've read it, but don't recall much of it, how did causality work as a weapon?

Aside from that, I feel that introducing causality into a sci-fi novel is fraught. Alastair Reynolds's The House of Suns has causality breaking as a consequence of wormholes and it makes no sense because the end point 'disappears' from view to those at the entry point. And by 'end point', we are talking whole galaxies suddenly becoming an abeyance in space. It was really contrived and the problem for me is that if you introduce causality, you are admitting to GR and that prohibits FTL in the first place. So, better to just assume post-Einstein physics and get on with it!

Though Derek Künske's The Quantum Garden has an interesting use of causality and wormholes. That's a recent release so...

The protagonist, Belisarius, has stolen a wormhole that has been, via handwavium, entangled with another to create a time machine. So, if Belisarius views an event in his current time, but only has limited knowledge of it, he can use the time machine to go back and change what is then his future. But, if he knows too much about it, that collapses his worldview to a definitive future and he cannot change it. That aspect is 'quantum' gobbledygook in the story, but Künske is a good storyteller so you mostly are swept along for the ride!
 
Tghu Verd said:
I've read it, but don't recall much of it, how did causality work as a weapon?

An attacking fleet tried to send itself tactical information about the enemy back in time. They actually found the time capsule. But it appeard to be a double-edged sword. Maybe it reather was a weapon sent by the enemy (or somebody else).
 
DrStupid said:
An attacking fleet tried to send itself tactical information about the enemy back in time. They actually found the time capsule. But it appeard to be a double-edged sword. Maybe it reather was a weapon sent by the enemy (or somebody else).

So it was the uncertainty of whether the information was correct? That's a good point, though you can get your brain into painful logic loops with that because if they'd found it sooner than they sent it, they'd know it would need to include incontrovertible proof of origin, so when they sent it, they would include it. Or not, time travel is very confusing :nb)
 
Tghu Verd said:
So it was the uncertainty of whether the information was correct?

You can't even be sure that the capsule contains information at all. It could also be a bomb to destroy or at least damage the fleet before the battle begins - some kind of temporal Trojan horse.
 
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Tghu Verd said:
So it was the uncertainty of whether the information was correct? That's a good point, though you can get your brain into painful logic loops with that because if they'd found it sooner than they sent it, they'd know it would need to include incontrovertible proof of origin, so when they sent it, they would include it. Or not, time travel is very confusing :nb)

What'll really cook your noodle is if you consider the idea that they send it back with proof (let's say, a marble), but they use the marble they found in the capsule in the first place. the questions are: how old is that marble, and where did it come from?

There's certainly some room for a very, very mind-bending twist with that concept...
 
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some bloke said:
the questions are: how old is that marble, and where did it come from?

The marble knows where it comes from but where do all you zombies come from?
 
DrStupid said:
The marble knows where it comes from but where do all you zombies come from?

Have you seen Predestination, @DrStupid? I'd say inspired by Heinlein's short though others say based on it, it's just about the most comprehensively mind bending, yet cohesive, time travel flick around.
 
Tghu Verd said:
Have you seen Predestination, @DrStupid? I'd say inspired by Heinlein's short though others say based on it, it's just about the most comprehensively mind bending, yet cohesive, time travel flick around.

I'd say it's close enough to '—All You Zombies—' to be based on it. It's the craziest time-travel story I'm aware of - and it's more than 60 years old.