PDA

View Full Version : Instantaneous gravitational effects?



cosmocrazy
2008-Mar-21, 08:33 PM
This is my first question on this site , and from what i have read most members who post on this site are a lot more knowledgeable than me so i,m looking forward to learning lots!. Hello to everyone and thanks for viewing my thread! :)

Does gravitational effect happen instantaneously or is it constrained to the speed of light? for example if the sun was suddenly to disappear would there be a delay in the gravitational effect (or lack of) felt by the earth instantaneously or would there be the 8 minutes or so delay (the time it takes for the light to travel to the earth from the sun) ? If so either way, would these effects apply to the other 3 fundamental forces known to physics? electromagnetism, strong and weak nuclear forces?? also is there a experiment possible to prove the effects either way? :think:

The universe has to be the way it is, so we are able to ask why the universe is the way it is.

Infinity Watcher
2008-Mar-21, 11:25 PM
This is my first question on this site , and from what i have read most members who post on this site are a lot more knowledgeable than me so i,m looking forward to learning lots!. Hello to everyone and thanks for viewing my thread! :)

Does gravitational effect happen instantaneously or is it constrained to the speed of light? for example if the sun was suddenly to disappear would there be a delay in the gravitational effect (or lack of) felt by the earth instantaneously or would there be the 8 minutes or so delay (the time it takes for the light to travel to the earth from the sun) ? If so either way, would these effects apply to the other 3 fundamental forces known to physics? electromagnetism, strong and weak nuclear forces?? also is there a experiment possible to prove the effects either way? :think:

The universe has to be the way it is, so we are able to ask why the universe is the way it is.

I'm no cosmologist or physicist, my experience with gravity is mostly confined to falling over, but I understand gravity is thought to propagate at the speed of light so if the sun were to disappear we wouldn't notice it for about the 8 minutes it takes, as I understand it the other forces are also SOL limited, as for experiments well we've measured the speed of light several times, not sure about the rest though, I'll leave that to wiser heads than mine.

Cougar
2008-Mar-22, 01:11 AM
...is there a experiment possible to prove the effects either way?
Welcome to the board, Cosmo. Apparently it's not an easy experiment to show that gravity propagates at c. However, here (http://en.wikipedia.org/wiki/Speed_of_gravity#Experimental_measurement.3F) is a brief write-up explaining what indications we do have that point toward confirmation.

EvilEye
2008-Mar-22, 01:34 AM
If the sun were to suddenly disappear from existence, we would go dark at the same moment that our orbit would fail.

There is no "propogation" so to speak.... it doesn't travel.

It just takes that long for the "effect" to be noticeable.

cosmocrazy
2008-Mar-22, 09:49 AM
thanks guys for your thoughts! i'll check out that write up Cougar, cheers.

trinitree88
2008-Mar-22, 05:33 PM
If the sun were to suddenly disappear from existence, we would go dark at the same moment that our orbit would fail.

There is no "propogation" so to speak.... it doesn't travel.

It just takes that long for the "effect" to be noticeable.

EvilEye. The 24 hour diurnal oscillation of the solar neutrino flux, seen at the Sudbury Neutrino Observatory in Ontario, would cease also at the speed of light travel, when the gravitational effect was observed. No sun, no solar neutrinos.:dance: pete