Why do on non-spherical objects create Gravitational waves?

Question

Sorry i meant to say why do ONLY non-spherical objects emmit graviatational waves

Ok im taking alot of heat for this question. But i was reading that scientists are trying to detect gravitational waves generated by quasars, black holes, etc. And the article said only non spherical objects would emit them. And some guy named semichild or somthing was the first guy to realize singularities may exist, but his model was based on a perfectley spherical black hole or neutron star or whatever he was working on. And that it would not generate the Gravitational waves

Answer 1

Where did you hear that only non-spherical objects can generate gravity waves? Any shape object, including spheres, should be able to generate gravity waves.

Gravity, or more properly the effect of gravity, is believed to "move" at the speed of light. Picture a large mass, like a planet, with gravity that extends to infinity. A distant object would be pulled toward the planet by it's gravity. More distant objects are pulled less strongly than nearby objects, but at least in theory the force pulling is never exactly zero no matter how far away you get. Now assume the planet suddenly moves to the left. An object 186,000 miles away would continue to be pulled toward the old location of the planet for a whole second after the planet moved, then it would feel the pull toward the new location of the planet, if gravity travels at the speed of light. Another object 1,860,000 miles away would still be feeling the pull toward the old position of the planet for 9 more seconds and then it too would feel the pull shift toward the new location of the planet. What is happening is the change in the direction of the pull of gravity of the planet propagates out into space at the speed of light. There is a kink in that gravity traveling out from the planet at the speed of light. That is a gravity wave. Now, a very heavy mass orbiting very fast around another very heavy mass would be a source of very strong gravity that was changing location all the time, producing continuous sine waves of gravity. It is believed that pairs of black holes orbiting each other very closely can make such a wave strong enough to be detected even light years away. But since the gravity of even a black hole is extremely small when felt from light years away, we would need EXTREMELY precise measurements to detect it. It would be measured kind of like this: Two balls on springs have their positions carefully measured. The first ball shifts position slightly as the direction of gravity changes when the wave passes, and a fraction of a second later the other ball shifts slightly. By measuring the distance between the balls to an accuracy of about a billionth of an inch and doing that about a billion times a second, in theory we could detect gravity waves. Of course any little shaking if the experimental setup would totally overwhelm such a small effect, so there are now proposals to do it in space by measuring the exact distance between two satellites flying in formation. The delicacy of measurement needed boggles the mind!

At least that is the theory as I understand it. So the shape of the mass makes no difference at all. But if gravity moves infinitely fast and not at the speed of light (or some other finite speed) then gravity waves are impossible. So detection of gravity waves would be proof positive that gravity is limited to the speed of light, or at least to some speed less than infinity. In fact the measurement should tell you how fast the wave moves as it passes the balls! BTW, they don’t have to be balls, any shape should work.

Answer 2

Okay enough of this lol. Gravity occurs simplisticly with four things. (1) Size of the object. (2) What it's made of as a whole. Does it have an iron core? (3) Rotation speed (4) speed with which it is traveling around our sun. Even our moon has a slight gravitational pull. Motion and size. Here on earth you weigh what your weighing sayyy 120 pounds. On Jupiter you'd weigh quite a bit more. Also because Jupiter has such a huge gravitational pull it keeps us and all the other planets in synch. Fancy that. All the planets have effect on each other pushing and pulling on each other. If it didn't occur we'd probably would have been a crispy critter before now.

Answer 3

Don't know where you got the notion that only non-spherical objects emit gravity waves. ANY object (mass) is capable of generating gravity waves, although such waves have not yet been detected. Two prime candidates for gravity-wave generation are colliding neutron stars and/or black holes, both spherical objects.

Answer 4

Gravity is a function of mass and the distance between the centre of two bodies. All objects with mass will create a gravitational field, including Earth, our sun, and the chair you are sitting on. Shape does not matter, except for finding distance from the centre of two bodies (it's much easier with a spherical object).

Answer 5

Its a pity the numpties did not read your question properly before giving you heat.

Yes, all bodies with mass act under gravity. But that does NOT mean they produce gravity waves. That would be like saying that because all wires react to electricity, they all spontaneously emit radio wave. Its just plain STUPID.

Your answer on the quadrupolar nature of gravity waves is spot on - you need changes in the gravitational potential to create gravity waves.

PS they are darned hard to detect.

Answer 6

gravitational radiation is quadrupolar. mass has to be oscillating alone two perpendicular axes. a single body needs to oscillate between being flattened at the poles to being elongated at the poles. two bodies in orbit also oscillate along two perpendicular axes. an imaginary line between the two masses rotates as they orbit so distribution of mass changes orientation every quarter orbit. it is not the individual bodies that emit gravitational radiation. it is the fact that they are orbiting each other.

did you read my answer? it is true, only non-spherical objects create gravitational radiation, but the mass of the object has to be oscillating. an object has to change shape, or objects have to orbit each other.


look here:
http://einstein.phys.uwm.edu/
http://en.wikipedia.org/wiki/Gravitational_radiation

Answer 7

Opps- functional mind's eye ! Theoretically it ought to look that he sphere will glow for ever (or perpetually ! ) yet almost no longer ! The source and the detector will bog down the mirrored image ! There must be proper 0 air / vacuum contained in the field, the floor of the field must be particularly skinny so as that no aberration is crated, The reflections from a number of aspects will intervene with one yet another. finally no longer some thing is eternal in this Universe ! !

Answer 8

All matter creates gravity, no matter its shape or size.