T0aD said:

Hi, I feel I have enough knowledge and willingness to be a moderator of the Science and Technology forum. There are already 4 mods but one more will just make it better  

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1) What is the speed of gravity?

2) What were Kepler's three laws of planetary motion?

3) What is the air speed velocity of an unladen swallow?

PS: You're a good guy TOaD, we'll keep you in mind!

Quote:

In the Einsteinian universe, instantaneity--that is, event X instantaneously causes effect Y at distance Z -- is impossible in a meaningful sense, since for reasons we needn't delve into it would involve communication at faster-than-light speeds. [Therefor], gravitational effects travel at exactly c, just like light.

This inspires two obvious questions: (a) How do we know gravity travels exactly at c? Answer: We don't, but it seems consistent with other things we know. To put it in technical terms, general relativity is only self-consistent if the speed of gravity is Lorentz invariant (that is, the same for all observers), and the only speed for which that works is c. (b) If gravity travels at the same speed as light, is it propagated by waves and particles, as light is? Answer: It seems likely. In fact, the gravitational particle has already been given a name: the graviton. But even though Einstein's theory of general relativity, which posited gravitational waves, was published in 1916, no unambiguous instance of gravitational waves or particles has ever been directly detected.?Indirect evidence for gravitational waves is very strong, however, such as the observations of the binary pulsar, which won the 1974 Nobel prize.

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II. Correct!

III. Also Correct! It was another trick question.  

Seuss said:

Almost correct. On Earth, the above is true. On the moon, the above is not true.

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