Swimming through spacetime

Nov 2017
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#1
Ever heard of this? https://www.sciencemag.org/news/2003/02/swimming-through-spacetime

I have an idea for a propellantless vehicle if this theory works, which is a pair of wheels on the same plane (axes of the wheels are parallel to each other) attached to each other and each driven by motors that spin them in opposite directions. I hypothesize that arrangement would allow this vehicle to both translate and rotate in spacetime on this plane, by adjusting the speed and direction of each wheel, and there's no propellant involved, so the motors could be powered with solar cells. To make one that can move around in spacetime in 3 (spatial) dimensions, just add a third wheel, and mount each wheel in planes in such an arrangement that makes them 120 degrees out of phase relative to each other.

The idea is that at the center of this vehicle, spacetime is compressed, and the points on the wheels closest to each other are moving through a distorted spacetime field relative to the spacetime field where the points on the wheels farthest away from each other.
 
Nov 2012
39,884
11,562
Lebanon, TN
#2
Solar power would not work. once they leave the solar system they have no solar energy to charge the solar cells.

Nuclear would be a better option.
 
Likes: Neil
Nov 2017
1,452
798
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#3
Solar power would not work. once they leave the solar system they have no solar energy to charge the solar cells.

Nuclear would be a better option.
That may be true, or there may be enough light radiating from all the stars in every direction - all over the "sky" - to provide the vehicle with enough of the energy that it needs, but what are we talking about here when we say "work"? Does it need to do work, or how much work does it need to exert to achieve much?

A car has to do work to keep itself moving to overcome deceleration from friction & wind resistance; on the other hand, by the law of conservation of energy, an object tossed out into the substantially empty void of space will essentially maintain its motion and direction indefinitely. If aimed correctly at its desired destination then it won't need to expend energy to make course adjustments.

Shoot for the stars - if the goal is to have the vehicle reach another star or solar system, it only has to get into the necessary (inverse square law) proximity of that star or sun in that solar system to draw enough energy from them.

There would be a problem if it's displacement in spacetime depended on these "flywheels" to keep spinning continuously and their bearings were introducing friction that dragged down their rotational speed, but the principles involved here could be applied to solve that problem: https://www.sciencedirect.com/science/article/pii/S1876610212001890
 
Jul 2014
13,525
8,187
massachusetts
#4
That may be true, or there may be enough light radiating from all the stars in every direction - all over the "sky" - to provide the vehicle with enough of the energy that it needs, but what are we talking about here when we say "work"? Does it need to do work, or how much work does it need to exert to achieve much?

A car has to do work to keep itself moving to overcome deceleration from friction & wind resistance; on the other hand, by the law of conservation of energy, an object tossed out into the substantially empty void of space will essentially maintain its motion and direction indefinitely. If aimed correctly at its desired destination then it won't need to expend energy to make course adjustments.

Shoot for the stars - if the goal is to have the vehicle reach another star or solar system, it only has to get into the necessary (inverse square law) proximity of that star or sun in that solar system to draw enough energy from them.

There would be a problem if it's displacement in spacetime depended on these "flywheels" to keep spinning continuously and their bearings were introducing friction that dragged down their rotational speed, but the principles involved here could be applied to solve that problem: https://www.sciencedirect.com/science/article/pii/S1876610212001890

That is the inertial drive system used to orient satellites, three flywheels each on different axis. Speed up the flywheel the satellite turns one way, slow it down the satellite turns the other way.
When A flywheel reaches it's maximum speed, you unload it against a thruster.
 
Likes: Neil
Nov 2017
1,452
798
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#5
That is the inertial drive system used to orient satellites, three flywheels each on different axis. Speed up the flywheel the satellite turns one way, slow it down the satellite turns the other way.
When A flywheel reaches it's maximum speed, you unload it against a thruster.
Yeah & I wonder how large & massive a set of flywheels would have to be in order to be able to produce a noticeable translation displacement (assuming this swimming through spacetime concept does work/exist); I'm not very familiar with the physics details & formulas involved, so it may have to be flywheels that are hundreds of meters in diameter (let's essentially suppose that it's an aluminum wheel with around a 1 cm squared cross sectional area, as opposed to say a hard polystyrene foam wheel).
 
Nov 2013
2,254
928
NM
#6
Yah. There's a discussion of this (July 2009) in a physics forum. The argument seems to be that this is more of a thought-experiment, with no or very little impact in the macro world. See Swimming in space-time

The conditions attached to the setup in the article referenced in the OP make me think in order to get this effect to work in the World we live in, you'd have to somehow replicate the conditions in the here & now. That's a tall order, it will take some very fancy mathematical footwork & serious engineering (& probably materials science, too).