What is the speed of gravity?

[newtonian]

formulaterp - Here is a relatively non-biased article on Van Flandern and gravity.<br /><br />http://www.absoluteastronomy.com/encyclopedia/t/to/tom_van_flandern.htm<br /><br />The questions are reasonable and certainly deserved to be answered rather than rejected as our of hand.

 

[raghara2]

<font color="yellow">What is your conclusion as to the speed of gravity in view of that excellent summary? </font><br /><br />This article is cleanly and nicely done. Conservation of an angularm momentum should have precedency before general relativity. It also seems that no aberation would cause another big problem to general theory of relativity. <br />So gravity should at least in effect act instantenously/nearly instantenously. <br /><br />I'm not fanatic into Einstain work, I use Lorentz relativity if I need to work with electromagnetical waves. But it seems more like some people are trying to defend theory they learned in school, just because they would be afraid to be without "widely known" theory.<br />

 

[eric2006]

"EINSTEIN'S THEORY OF RELATIVITY <br /><br />In 1915 Einstein formulated a new theory of gravitation that reconciled the force of gravitation with the requirements of his theory of special relativity. He proposed that gravitational effects move at the speed of c. He called this theory general relativity to distinguish it from special relativity, which only holds when there is no force of gravitation. General relativity produces predictions very close to those of Newton's theory in most familiar situations, such as the moon orbiting the earth. Einstein's theory differed from Newton's theory, however, in that it described gravitation as a curvature of space and time."<br /><br />The difference in theory grows evident on larger scales doesn't it? Take for instance the orbit of Mercury. I think Newtonian Physics has not an explanation for it.

 

[newtonian]

ragharA2- Acknlowledged. I request time to study the article more, and do research - but thank you for the article.<br /><br />Meanwhile - Have you considered why gravity can be emitted from mass within black hole's event horizon?

 

[newtonian]

Eric 2006 - Yes, for local effects Newton's laws are fine.<br /><br />Relativity involves approach to high relative speeds.<br /><br />The paradox is that this is relative - the object may not "know" it is approaching c!<br /><br />Put another way: earth and solar system are approaching c from the viewpoint of an observer near our visibility horizon who is expanding from us approaching c!<br /><br />However - from another vantage point, you may not be moving at all - but at rest!<br /><br />OK, I forget the point about Mercury.<br /><br />Anyone remember?

 

[eric2006]

From: http://en.wikipedia.org/wiki/Mercury_%28planet%29#Orbit<br /><br />Orbit<br />The orbit of Mercury has a high eccentricity, with the planet's distance from the Sun ranging from 46 million to 70 million kilometres; only Pluto among the major planets has a more eccentric orbit. However, because of the smallness of Mercury's orbit, all of the planets except the Earth and Venus have a larger spread between perihelion and aphelion (Mars' is 42.6 Gm to Mercury's 23.8 Gm, for example); there are even several outer planet satellites that beat Mercury's spread: Saturn's S/2004 S 18 (with 30.8 Gm) and Neptune's S/2003 N 1 and S/2002 N 4 (42.0 and 47.9 Gm, respectively).<br /><br />When it was discovered, the slow precession of Mercury's orbit around the Sun could not be completely explained by Newtonian mechanics, and for many years it was hypothesised that another planet might exist in an orbit even closer to the Sun to account for this perturbation (other explanations considered included a slight oblateness of the Sun, and so forth). The hypothetical planet was even named Vulcan, but in the early 20th century, Albert Einstein's General Theory of Relativity provided a full explanation for the observed precession. Mercury's precession showed the effects of mass dilation, providing a crucial observational confirmation of Einstein's predictions. This was a very slight effect: the Mercurian relativistic perihelion advance excess is a mere 43 arcseconds per century. The effect is even smaller for the remaining planets, being 8.6 arcseconds per century for Venus, 3.8 for the Earth and 1.3 for Mars.<br /><br />Research indicates that the eccentricity of Mercury's orbit varies chaotically from 0 (circular) to a very high 0.47 over millions of years. This is thought to explain Mercury's 3:2 spin-orbit resonance (rather than the more usual 1:1), since this state is more likely to arise during a period o