gravity waves ......?

Question

is the speed of gravity waves infinity or do they move at the speed of
light? Is there any experimental data to support either answer. If it is instantaneous could GW be used as the ultimate long rangecommunication tool?If an object is 5000 light years away and then dissappears how can anobject 5000 years later be attracted to something that is not there ifGW is limited to the speed of light?

Answer 1

General relativity predicts the existence of gravity waves that travel at the speed of light. There is no direct experimental evidence this, since gravity waves have never been detected directly. Theradiative decay of the orbit of a binary pulsar was the first indirect measurement of the effect of gravity waves, but did not establish a velocity for the waves. General relativity is well supported by experimental evidence and, so far as I know, any plausible theory of gravitation predicts gravity waves that travel at the speed of light.

The second part of your question is about the speed of propagation of gravitational fields, not of gravity waves. Again, however, they propagate at the speed of light. If a massive object suddenly moves,remote objects experience a force that points to the old position,until the disturbance in the gravitational field reaches them,traveling at the speed of light.Exactly the same is true for the electric field of a charged particle.

Answer 2

Einstein's work in special and general relativity showed that gravity is not instantaneous as Newtonian physics assumed. Instead, gravity is something like a wave, as you said. The wave spreads out towards infinity over time, but weakens as it travels further from the source. (The image of a bowling ball on an old mattress is often used to show how gravity bends space, but the idea of ripples in a pond better illustrate how gravity 'waves' expand.) Thus something 5000 light years away could indeed feel the gravitational pull of an object that isn't even there anymore. However, the object would have to be incredibly massive (like a couple black holes hanging out together) for the effect to be noticeable.

Answer 3

Gravitational waves are predicted to travel at the speed of light, according to Einstein's General Theory of Relativity. This was one of its testable predictions; however, as of yet it has not been experimentally confirmed because they are so difficult to detect and measure. Since the General Theory has essentially otherwise been proven as true, it is safe to assume that this prediction is true as well, but there are still people trying to measure it.

It is important to note that in Newton's theory of gravitation, which is written simply as F = G x m1 x m2 / r^2, where G is the gravitational constant, there is no reference to any kind of speed or time. The gravitational constant has no units as such. This is in contradistinction to the equations for electricity and magnetism, for which there results a constant which actually HAS units of meters/sec. This constant is, of course, 3 x 10^9 meters/sec, which is the speed of light.

Since the equations for electromagnetism produce a constant that refers to a speed, but gravity does not, for many years, people assumed this meant gravity travels at infinite speed, which seems an intuitive, if somewhat presumptuous conclusion.

The General Theory of Relativity concludes that gravity is simply a distortion in space-time caused by the presence of matter. The theory actually derives the speed of the motion of these distortions, and calculates that they travel at the speed of light. However, the theory does NOT explain why this should be or how it works, only that it happens.

More recently of course, people have hypothesized these "distortions" are caused by the radiation of gravitons, theoretical massless, non-interactive particles that trigger these space-time distortions. However, there is so little empirical evidence to support this area of theory that much of it is still controversial.

Answer 4

Hi. Current thinking is that the force of gravity may use the exchange of particles called 'gravitons'. They're VERY weak. The wake from a passing ship can reach you long after the ship is out of sight. Same with gravity waves. The strongest, and maybe just detectable, gravity waves may be released by two merging black holes or maybe even neutron stars. They would orbit in times approaching zero and 'shake up' the surrounding space.

Answer 5

First, I have to assume you mean gravational waves, not gravity waves.

Gravaional waves travel at the speed of light according to the latest theory (however, while they have been indirectly shown to exist, they have never been directly detected, so no direct measurement of their speed has been made).

Also, you would need a method of generating these waves in order to use them for communications or anything else.

Answer 6

There are no gravity waves as such. Gravitational radiation has not been measured, it has only been shown to exist and only as it relates to the curvature of space-time.

Gravity itself is not a wave or a particle. It is a force, and that force does not TRAVEL at all. Mass attracts mass. The force by which it attracts is called gravity. Gravity does not propagate outward, it simply exists as a force and is static as the mass is static.