Spacetime displacement.

[Themohawkninja]

I was thinking the other day about how every military sci-fi space ship that I have ever seen uses naval terms. You have the port and starboard sides, you might have torpedoes instead of missiles. The highest ranking officer is an admiral, an he may or may not command a fleet of ships.

So, to keep with the motif of naval terms, I was thinking, could you get away with replacing the mass of a space ship, with its' spacetime displacement? That is to say, a ship with a spacetime displacement of x (kg/T/whatever) means that the ship distorts spacetime as if it had the mass of x (kg/T/whatever).

[Winter Man]

Thing is, for every ship it'd have a value of 'negligible'.

[Themohawkninja]

Thing is, for every ship it'd have a value of 'negligible'.

Why do you say that?

I suppose it should be noted here that such a term is meant for a universe whereby we could accurately detect such spacetime distortions.

[DaveofDefeat]

Seems like it'd be easier to say it weighs 10,000 metric tons than to say it has a gravity displacement of 10^-100

[Winter Man]

Why do you say that?

I suppose it should be noted here that such a term is meant for a universe whereby we could accurately detect such spacetime distortions.

Because a planet will distort spacetime noticeably, but we're talking something 18 orders or magnitude larger than a very large spaceship (6E24 vs. around 1E6). If we had accelerometers accurate enough to detect the gravity of a spaceship even within a few kilometres, they'd be thrown off awfully by your own crew moving around your ship.

[Themohawkninja]

Seems like it'd be easier to say it weighs 10,000 metric tons than to say it has a gravity displacement of 10^-100

You'd still say 10,000 metric tonnes, it's just that you are indirectly referring to it's mass.

[Themohawkninja]

Because a planet will distort spacetime noticeably, but we're talking something 18 orders or magnitude larger than a very large spaceship (6E24 vs. around 1E6). If we had accelerometers accurate enough to detect the gravity of a spaceship even within a few kilometres, they'd be thrown off awfully by your own crew moving around your ship.

You wouldn't bother weighing it with people on board then.

[Winter Man]

It might also be worth pointing out that spacetime doesn't 'displace' like a fluid. It distorts, but you can't really measure how deep a gravity well is without knowing the distance to an object as well as your 'gradient' on the curve. So it's kind of pointless to even bother describing it in such a roundabout way.

[Wahgineer]

slightly out of context: Yeah, almost everything in sci-fi military has a navy term: like for how a space ship is called a spaceship.

Back on target: the ships mass IS a measure of its space time displacement.

[dharak1]

Tons and kilograms are mass though. Newtons are force. Unless I'm crazy.

[Themohawkninja]

It might also be worth pointing out that spacetime doesn't 'displace' like a fluid. It distorts, but you can't really measure how deep a gravity well is without knowing the distance to an object as well as your 'gradient' on the curve. So it's kind of pointless to even bother describing it in such a roundabout way.

I know, but I figure that a distortion is a sort of displacement, since you are displacing part of the space it a given area, even if it isn't a translational displacement.

[Themohawkninja]

Tons and kilograms are mass though. Newtons are force. Unless I'm crazy.

No, that's correct.

[Winter Man]

I know, but I figure that a distortion is a sort of displacement, since you are displacing part of the space it a given area, even if it isn't a translational displacement.

Problem is the distortion isn't actually real, just a convenient way of looking at things. Like how when we're young we're told electrons orbit an atom. The analogy completely breaks down. The two sensor readings on your ship are acceleration and distance, they combine to give you mass. The only use for such a system is identifying an unknown object, be it ship, asteroid, etc. in which case your ship will be crewed. Could make a good plot point in a sci fi, having them all have to stay completely still and silent while they were scanning, kind of like on a submarine (albeit reversed).

[MC.STEEL]

and suddenly le wild sci fi movie/game that uses this idea appears.