Effects of gravity throughout space-time?

[TrentonF]

TL;DR

Because spacial and temporal dimensions are the same, and gravity affects space, would the effect of gravity extend through time?

Can the effects of gravity possibly extend through time? Is there a natural law that forbids this?

Could this be a possible explanation for dark matter?

 

[russ_watters]

Summary: Because spatial and temporal dimensions are the same, and gravity affects space, would the effect of gravity extend through time?

Can the effects of gravity possibly extend through time?

Well, yes, space and time are linked and gravity acts on both and objects/fields travel/extend through both.

Could this be a possible explanation for dark matter?

No, this bears no relation to dark matter.

 

[PeroK]

Summary: Because spatial and temporal dimensions are the same, and gravity affects space, would the effect of gravity extend through time?

Can the effects of gravity possibly extend through time? Is there a natural law that forbids this?

Could this be a possible explanation for dark matter?

Gravity is determined by the geometry of spacetime. In fact, you could say gravity is the geometry of spacetime.

Gravity influences the motion of particles and radiation.

 

[TrentonF]

No, this bears no relation to dark matter.

Isn't dark matter just an unidentified force of gravity that holds galaxies together?

If galaxies are held together by their own gravitational influence and that of a past state, could this not reasonably be an explanation for the excess of gravitational forces observed in galaxies?

Or is this already taken into account when determining the forces required to hold together a galaxy?

 

[PeroK]

Isn't dark matter just an unidentified force of gravity that holds galaxies together?

If galaxies are held together by their own gravitational influence and that of a past state, could this not reasonably be an explanation for the excess of gravitational forces observed in galaxies?

Or is this already taken into account when determining the forces required to hold together a galaxy?

If gravity behaved that way we would already see that in terms of the effect of the Sun's gravity on Earth etc.

An alternative to dark matter is "modified" gravity, where gravity is assumed to work differently, but in such a way that it is only noticeable over large distances.

You could search for MOND if you are interested.

 

[russ_watters]

Isn't dark matter just an unidentified force of gravity that holds galaxies together?

If galaxies are held together by their own gravitational influence and that of a past state, could this not reasonably be an explanation for the excess of gravitational forces observed in galaxies?

Or is this already taken into account when determining the forces required to hold together a galaxy?

There's 2 options:
A. There's matter in galaxies that we can't see.
B. We don't understand gravity as well as we think.

Scientists believe it is "A". Given how good the theory has worked relatively locally, it would be tough for there to be something major working differently at long distances.

 

[ohwilleke]

Scientists believe it is "A". Given how good the theory has worked relatively locally, it would be tough for there to be something major working differently at long distances.

Some scientists believe "A" and some believe "B" and many are agnostic. The data is constantly coming in and generally speaking, tilting the balance away from A and towards B, although not necessarily decisively, and most of the early dark matter particle models involving SUSY WIMPs have been all but ruled out.