raul_l said:I guess my point is that gravity may get faster from point A to point B but it doesn't necessarily mean that light is slower than gravity.
According to general relativity, the gravitational field produced by a rotating object (or any rotating mass-energy) can, in a particular limiting case, be described by equations that have the same form as the magnetic field in classical electromagnetism
...GR shows...(rapidly moving masses) will give rise to oscillatory gravitational waves which propagate at the same rate of speed as electromagnetic waves (pg213)...and are polarized resembling in this respect electromagnetic radiation...but having different polarization characteristics...(pg 137)...
mgb_phys said:Does gravity have the same absorption emmission effects as photons?
Anyway there is no reason things can't go faster than light in a medium, neutrinos go faster than light almost everywhere. In an extreme case such as a star it takes photons 100,000years to get out but neutrinos make it in almost 'c'
mgb_phys said:Yes, I don't think there is much of a refractive index for gravity waves (could be wrong) but my guess would be gravity first then neutrinos then light last!
mgb_phys said:Correct - strictly speaking gravity doesn't travel (it's a property of the local space time) changes in gravity do propagate at the speed of light.
mgb_phys said:Perhaps I didn't explain it very well.
Gravity is already here it's not a property of an object it's a property of space, but changes in gravity have to travel.
It's like standing in the sea - the water is a certain depth, but changes in the depth of water have to travel, in this case as waves, at a fixed speed.
if space is nothing, how can nothing have properties?
Good post ... if space were nothing, it wouldn't exist.Naty1 said:It likely can't. Hence it appears space IS something! It also contracts relativistically. And apparently have a minimum size: Planck length, a minimum area, Planck area, etc.
Likewise, time is something we know even less about it...how fast does it travel?? Without space, inflation theory suggests faster than light.
One "picture" (construct) of space is from Roger Penrose spin networks: a geodesic configuration with edges corresponding to areas and nodes corresponding to volumes, each in multiples of Planck length...these change in Planck multiples as gravity "curves" spacetime...
All in all, rather very theoretical...and a bit confusing!
And for those who think otherwise..try this from NASA on for size:
http://einstein.stanford.edu/content/relativity/a11134.html
Regarding the speed of light:
http://einstein.stanford.edu/content/relativity/q197.html
(question # 204)
gothspeed said:Good post ... if space were nothing, it wouldn't exist.
I'm guessing none yet...that's what my reference to Stanford/NASA suggests...I'm reasonably sure no gravitational waves have been detected...yet...hopefully that will make headlines!What experiments have been performed to actually measure the speed of gravity?
from... http://einstein.stanford.edu/content/relativity/q2381.htmlPhysically, curvature just represents a change in the strength of a gravitational field produced by either mass of energy that is located in some particular location in space, and at some particular instant in time.
Naty1 said:I'm guessing none yet...that's what my reference to Stanford/NASA suggests...I'm reasonably sure no gravitational waves have been detected...yet...hopefully that will make headlines!
...... I agreed with Naty1's reference:Topher925 said:Thats a bit of a paradox, don't you think?
..........
+1 ... :)Naty1 said:Goth.. Don't get too worked up if you agree...others will not...but nevertheless its an interesting subject area...
mgb_phys said:Does gravity have the same absorption emmission effects as photons?
Anyway there is no reason things can't go faster than light in a medium, neutrinos go faster than light almost everywhere. In an extreme case such as a star it takes photons 100,000years to get out but neutrinos make it in almost 'c'
sai_2008 said:WHAT? Neutrinos go faster than light? Really?
Neutrinos have non-zero rest mass so how can they go faster than c...??
ZapperZ said:Nothing that mgb said "in a medium...". This is how we detect neutrinos in the first place, and this is how we get cerenkov radiation.
Zz.
"Gravity Faster Than Light" is a theoretical concept that suggests the existence of particles or waves that travel faster than the speed of light. It challenges the fundamental principle of Einstein's theory of relativity, which states that the speed of light is the maximum speed at which any matter or information can travel.
The theory of relativity states that nothing can exceed the speed of light, and any object with mass becomes infinitely heavy as it approaches the speed of light. "Gravity Faster Than Light" proposes that certain particles or waves can travel faster than light, which would challenge the fundamental principles of the theory of relativity.
Currently, there is no direct evidence supporting the existence of "Gravity Faster Than Light." Some scientists have proposed that certain astronomical phenomena, such as the expansion of the universe, could be explained by particles or waves traveling faster than light. However, these theories are still speculative and require further research and evidence.
If "Gravity Faster Than Light" were proven to exist, it would challenge our current understanding of the laws of physics. It could potentially open up new possibilities for space travel and communication, as well as provide a deeper understanding of the universe and its origins.
Scientists are studying "Gravity Faster Than Light" through various theoretical and experimental methods. Some are conducting experiments with particle accelerators to search for evidence of particles traveling faster than light. Others are using mathematical models and simulations to explore the potential implications of this concept on the laws of physics.