Gravity & Time

[phil_newby]

I wonder about Gravity; why is it apparently so weak and yet we hope there is loads of dark matter to explain how strong it is overall - and is it really so different from the other forces?

 

if it is a force mediated by a particle like a graviton - similar to the photon mediating the EM force, can a graviton escape the gravity of a black hole in a way that photos can't - or do they only go inwards?

 

i've heard speculation that gravity's apparent weakness might be that it seeps away into/through other hidden dimensions. As time is also a dimension - could gravity seep through time in a way that other forces don't seem to?

Could the gravitational effects we describe as dark matter actually be the accumulated effect of the gravity of past and future masses seeping through time?

 

Is gravity's bending effect on space-time another way of describing this seepage?

Edited July 23, 2015 by phil_newby

[ajb]

if it is a force mediated by a particle like a graviton - similar to the photon mediating the EM force, can a graviton escape the gravity of a black hole in a way that photos can't - or do they only go inwards?

If we treat classical gravitons on a fixed background then gravitons would follow null geodesics just as light does. I do not think they would escape from an event horizon. Maybe something funny could happen in the full quantum theory, we just don't know.

 

i've heard speculation that gravity's apparent weakness might be that it seeps away into/through other hidden dimensions. As time is also a dimension - could gravity seep through time in a way that other forces don't seem to?

This is one possible explanation; gravitons could propagate in higher dimensions and so create a weaker force from our perspective. However, these extra dimensions are usually 'spacial' and so I am not sure how to answer your question. People do think about theories with more than one time, but I am no expert in that.

 

 

Could the gravitational effects we describe as dark matter actually be the accumulated effect of the gravity of past and future masses seeping through time?

 

Is gravity's bending effect on space-time another way of describing this seepage?

That is an interesting idea, but I have no idea how to formulate that properly. One obvious problem is that of causality and time travel in general relativity. It is not obviously ruled out and so you could be thinking of gravitons whizzing round closed time-like curves. I am not sure how much people have thought along these lines.