spacetime = . . .

[lemur]

Can it be said that any particle or object in the universe has a certain amount of force required to reach any given destination? So instead of talking about "escape velocity," couldn't one speak of "destination force?" "Escape velocity" implies that once a particle or object reaches a certain speed, it will no longer return to the gravity-well it's being launched out of, but what about its destination? If you took account of its destination, wouldn't any particle/object have a certain velocity (speed and direction) needed to escape ALL possible destinations and remain in its own gravitational frame forever? Likewise, wouldn't any other object be on a trajectory to some other gravity-well destination, and thus have a certain amount of force required for it to reach that destination? As such, couldn't spacetime be referred to in terms of the amount of force required for one object/particle to reach some other destination object/particle?

[swansont]

No. You can change force and still do the same amount of work by changing the distance over which you apply the force.

[lemur]

No. You can change force and still do the same amount of work by changing the distance over which you apply the force.

Maybe I should have said, "work to destination" instead of "force to destination." I forgot that force was an intensity instead of a quantity of action.

 

 

 

[swansont]

In that case, yes, it can be. It's the energy you need, for a bound system. For a free system, the lower bound is zero. In those cases the variable is how long it takes.

[lemur]

In that case, yes, it can be. It's the energy you need, for a bound system. For a free system, the lower bound is zero. In those cases the variable is how long it takes.

Ok, but then what if you extended this idea to the practical level and said, for example, that the amount of work required to move something from mercury to venus is the same as the same amount of work required to move the same mass from, say, uranus to neptune (assuming the amount of work would be the same). Then, could you say that the amount of spacetime between both sets of planets is the same because the same amount of work is required to reach each destination from the other?

[Essay]

Ok, but then what if you extended this idea to the practical level and said, for example, that the amount of work required to move something from mercury to venus is the same as the same amount of work required to move the same mass from, say, uranus to neptune (assuming the amount of work would be the same). Then, could you say that the amount of spacetime between both sets of planets is the same because the same amount of work is required to reach each destination from the other?

 

That might work for light, but for matter you'd have to know the destination beforehand; and while I don't know why, we don't seem to be able to predict things in macrospacetime.

 

The perspective you describe seems as if it would require that you account for the gravity of the destination as a part of the initial conditions... or words to that effect. I try to avoid thinking about physics too much; it takes up too much processing time and space (capacity)... hmmmmm: equating space and capacity.... See! Too much! So now I must go and think about the more comforting biochemistry of metabolic processes. But yea, I'm convinced we do need a different perspective on spacetime; you are on to something here I think. Cheers!

 

~

[swansont]

Ok, but then what if you extended this idea to the practical level and said, for example, that the amount of work required to move something from mercury to venus is the same as the same amount of work required to move the same mass from, say, uranus to neptune (assuming the amount of work would be the same). Then, could you say that the amount of spacetime between both sets of planets is the same because the same amount of work is required to reach each destination from the other?

 

I don't know about the phrase "amount of spacetime," but there are things you could probably relate about the curvature. Someone more familiar with GR could say more.

[lemur]

That might work for light, but for matter you'd have to know the destination beforehand; and while I don't know why, we don't seem to be able to predict things in macrospacetime.

 

The perspective you describe seems as if it would require that you account for the gravity of the destination as a part of the initial conditions... or words to that effect. I try to avoid thinking about physics too much; it takes up too much processing time and space (capacity)... hmmmmm: equating space and capacity.... See! Too much! So now I must go and think about the more comforting biochemistry of metabolic processes. But yea, I'm convinced we do need a different perspective on spacetime; you are on to something here I think. Cheers!

 

~

You're right, it would be less practical to come up with the destination of every spacetime-traversal at the point of embarking, but I'm not really arguing for methodology. My point is to theoretically address the idea of spacetime as being an "energetic separation" between points instead of viewing the points as passively inhabiting some kind of imaginary grid. So by viewing spacetime as a certain amount of potential-work between objects/particles, all motion would be is working to bring matter or energy waves into contact with each other. So spacetime would really just be an amount of work from A to B and of course the time experienced by the traveller (or an external observer) that the traveller is in transit. Is work/time energy or power or something like that?