Does gravity have a "speed"?

Question

What is the speed of gravity and how does it compare to the speed of light?

Answer 1

No.

Acceleration DUE TO (earth) gravity is approx.9.8 m/s^2.

THINGS falling have an instantaneous speed.

Gravity is a FORCE.

Only MATTER in motion can have SPEED.

.

Answer 2

If you are looking for the "speed" of gravity Sal's answer is correct.  Newton looked at gravity as force.  If it is a force, then if the sun were to suddenly go away, then the pull the sun puts on the earth would go away in the same instant.  However, under Einstein's theory,  the earth would continue to orbit the sun until the same instant that the last ray of light got to the earth.  At that moment it would proceed in a straight line tangent to its former orbit.  So Einstein postulated the "speed of gravity" as equal to the speed of light.

There is quite a difference in the acceleration due to gravity which is how gravity accelerates a body over time.   Acceleration due to gravity is different on the earth than it is on the moon or any other body in our solar system.

Answer 3

the speed of gravity if 9.8 meters per second, but I don't know anything specific about the speed of light. sorry

Answer 4

Not sure that the anwer to this is known. The speed of light is one guess, but other observations suggest that it may well be instantaneous.

There are two effects assocaited with mass gravity and inertia. The gravity is the easier of the two to explain away, the inertia is a bit more problematic and may require gravity to propagate instantaneously (see Mach's principle).

Answer 5

Gravity accelerates things at a rate of 9.8 meters per second which is INCREDIBLY SLOW compared to speed of light. Technically, since it is downward, it is -9.8m/s. There you go.

Oh, it's acceleration, not speed. They are different.

Answer 6

Gravity is a force, while the speed of light in vacuum is a velocity. Forces induce acceleration, which is a change in velocity. So no, gravity doesn't have a speed.

However, the hypothesised gravity particles, called gravitons, are thought to be massless themselves, so their velocity can be as high as the speed of light in vacuum. You could say that gravity 'has' a speed at which it lets masses interact gravitationally. Actually, all causal interaction between anything in the universe is limited by this specific velocity, as pointed out in the second answer.

Note that light does not necessarily travel as fast as photons (light 'particles') in vacuum. When photons pass through a non-vacuum, they slow down.

Answer 7

it doesn't technically have a speed but according to einstein, if one were to remove the Sun from our solar system, each planet would not leave their orbit instantly.  He said that it would take about 8 minutes, same time it takes for the suns rays to reach earth, for earth to leave the orbit tangent to its current position and proportionately the same for other planets.

Answer 8

The action and properties of gravity is still not understood well.

Some theories regard it as an exchange of momentum via 'gravitons', elementary particles that have either the speed of light, or (according to the CPH theory) a speed 10^20 times the speed of light.

Other theories treat gravity as if it were a curvature of space. The acceleration vector due to gravity points in the direction of where the two massive bodies are now, not where they were when light arriving now was emitted. This is equivalent to assuming that the force of gravity having an infinite speed.

Answer 9

gravity has an acceleration of 9.8 m/s squared

speed of light is  299 792 458 m/s or 3.0x10^8 m/s for easier calculations.

i found some websites on the internet that may help you. the one quotes, "When we apply these techniques to gravity, they all yield propagation speeds too great to measure, substantially faster than lightspeed. This is because gravity, in contrast to light, has no detectable aberration or propagation delay for its action, even for cases (such as binary pulsars) where sources of gravity accelerate significantly during the light time from source to target"

this tells me that it's not possible to see if gravity is faster than light. from what i know about gravity, i see it as somethign that is constantly accelerating where the speed of light is a constant speed, impossible to compare the two. it's like apples and oranges!!  hope this helps a bit

Answer 10

A good question! A previous answer is confusing acceleration, due to Earths gravity at sea level, with what I think you mean. The light from the sun takes eight minutes to reach Earth. The sun has a powerful effect on the gravity on Earth. If the sun suddenly ceased to exist we wouldn't observe it until eight minutes later. Your question, I believe, is would the effect on gravity on Earth take eight minutes, would it take longer or be instantaneous? I have read recently that physicists claim it would be instantaneous. Therefore, the speed of gravity is infinite. I'm sorry that, without reading the last four books on modern physics again, I can't give you a reference.

Answer 11

hello i hope this answers you're question...

every solid objects has a gravity field, even you and me. If i stand next to a bouncy ball for the rest of my life gradually it will get closer to me because my gravity force is pulling it too me .The size of the mass determines the amount of gravity it exerts. Because the earth has such a big mass it has a high gravity force, whereas the moon has a smaller gravity force because it has a smaller mass. So the bigger the mass and the gravity force the quicker the object pulls things to the centre.

Answer 12

Current theory is that gravity travels at or near the speed of light. If the sun were to instantaneously cease to exist, we would not know about it for about 8.3 minuets, the time it takes light to reach us. Earth would then move in a straight line into space.