09-01-2003 16:38									#1
	It is proven. Gravity expands at speed of light Support Apolyton, buy Civilization III: Complete

Gravity expands at speed of light

It was proven today that gravity expands at the speed of light. This proves Einsteains theory. newton was convinced that the speed of gravity was infinite. The speed of gravity has until now been an unknown constant.

It was discovered that the planet Jupiter would pass by (as seen from earth) the quasar JO842+1835 on september 8 2002. This meant that radiowaves from the quasar would be slightly bent as they passed the gravitational pull of Jupiter on their way to earth. the signal was picked up by the Very Long Baseline Array, a collection of large radio recievers on Earth placed in Hawaii, United States and Germany.
The accuracy of the experiment compares to measuring the thickness of a human hair as seen from a distance of 400 kilometres.

Until know gravity has been the great unknown and it is thus a step forwards towards a total and collective understanding of laws of the universe.

	09-01-2003 16:45									#2
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Link?

	09-01-2003 16:46									#3
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Speaking as a postgraduate Physics student, how does that prove anything beyond the fact the light is affected by gravity? Please give us a link, or explain further. You have intrigued me - can you give me more?

	09-01-2003 16:46									#4
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http://www.jamaicaobserver.com/news...AVITY_SPEED.asp

	09-01-2003 16:48									#5
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It's in today's New Scientist...there's a link on the New Scientist site to snippets from the article.

	09-01-2003 16:49									#6
	Re: It is proven. Gravity expands at speed of light Tired of ads?

quote: Originally posted by Tripledoc The accuracy of the experiment compares to measuring the thickness of a human hair as seen from a distance of 400 kilometres.

Such analogies can be misleading.

Here it is: gravity does move at the same speed as light. Our actual figure was 1.06 times the speed of light, but we have an error of plus or minus 0.21. (...) This vindicates Einstein's instinct when formulating his general theory of relativity."

	09-01-2003 16:51									#7
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www.space.com

I am Cybersix on their boards, but I don't post much 'cause they're overrun by UFO nuts and van Flandern foolios.

What does this mean for Inflation? How can space expand faster than gravity, if gravity is the curvature of space?

	09-01-2003 17:08									#8
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My information was from the Tycho Brahe institute in Denmark. Incidentally Ole Roemer, another Dane, was the first to approximate the speed of light sometime in the 17th century. Funnily enough by observing Jupiters moons.

edit: name confusion corrected

Last edited by Tripledoc on 09-01-2003 at 19:31

	09-01-2003 17:28									#9
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Why do I always feel like a 4 year in these kinds of threads

* and another thing flies over alva's head *

	09-01-2003 17:34									#10
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It's not really much of a surprise since GR has been experimentally tested and gravity propagating at c is an essential ingredient of GR. But it is nice to have a direct test too

	09-01-2003 20:07									#11
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quote: Originally posted by alva Why do I always feel like a 4 year in these kinds of threads * and another thing flies over alva's head *

yep, i'm the same, i'm interested in this sort of stuff, but need it broken down into 'coffee table book' style before i can digest it!!

	09-01-2003 21:01									#12
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I don't know much about the theoritical stuff either.
But I think its fun to think that the force which keeps you to the ground has a definate speed.

By the way is an anti-gravitational device possible in theory?

	09-01-2003 21:12									#13
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Is gravity a wave or a particle or both?

	09-01-2003 21:21									#14
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I think both, but it could be neither.

Both, because everything has wavelike properties. But AFAIK, the wave's frequency is a function of It's mass, and I really don't see the messanger particles of gravity being influenced by each other.

In short: I don't know.

	09-01-2003 21:26									#15
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quote: Originally posted by MrWhereItsAt Speaking as a postgraduate Physics student, how does that prove anything beyond the fact the light is affected by gravity? Please give us a link, or explain further. You have intrigued me - can you give me more?

I am with you. The test only detects electromagnetic waves, not gravity. If anything, it shows that EM waves travel at c, which is something we know.

	09-01-2003 21:37									#16
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I think I agree as well. The gravitational pull of Jupiter influenced on the radiowave all the way from the Quasar, It's not that a new source of gravity has popped up, and after some time passed has actually bent the wave that way. If that would be the case, we could say that gravity's velocity was: (distance between the wave and the gravity source when the gravity source appeared) divided by (the time from the appearance of the object to the distortion of the wave)

I can't wait for the physics cources next simester.

	09-01-2003 21:50									#17
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from www.space.com
"Jupiter's gravity would bend the light ever so slightly, they knew. The question was by how much. Theory predicted two separate circles, slightly offset from one another, that the galaxy should appear to describe on the sky as Jupiter got close, closer, and then moved away.

The results show, within a 20 percent margin of error, that gravity worked at the speed of light."

I think this actually clarifies. It is the speed of gravity which have been observed.

Am I correct that they were able te 'see' two galaxies at the same time?

	09-01-2003 21:59									#18
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Some scientific papers claim that the speed of light was faster way back when than it is now. If this is true how would it compare to the new finding and what would the implications be for the age of the earth?

	09-01-2003 22:15									#19
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The speed of light thing dealt with changes in the early universe (we're talking first fractions of a second here)...I don't think they have any effect on the ~12 billion year age of the universe as currently observed.

	09-01-2003 22:18									#20
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The stuff I read (sorry no link) talks about huge differences in the speed of light. Much faster before. It might have declined gradually.

	09-01-2003 22:35									#21
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Interesting, surely that would be expected as the gravitational influence of a planet would coincide with where the planet is visualised anyway?

	09-01-2003 22:51									#22
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quote: Originally posted by Azazel I think both, but it could be neither. Both, because everything has wavelike properties. But AFAIK, the wave's frequency is a function of It's mass, and I really don't see the messanger particles of gravity being influenced by each other. In short: I don't know.

isnt graviton a particle of gravity?

	09-01-2003 23:18									#23
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sorry I don't believe it.

I have heard that the rate the universe is expanding is acclerating. Therefore it cannot stay at the speed of light. Has to deal with dark energy.

	09-01-2003 23:23									#24
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quote: Originally posted by Calc II isnt graviton a particle of gravity?

It's still just theoretical.

	09-01-2003 23:44									#25
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the de-broglie equation says that all things have wavelike properties. The smaller the particle is, the more it is relevant. For example, contrary to what many people think, you can't see the electrons mooving around the nucleus in nice circular patterns. The electron is actually a cloud around the nucleus. That cloud takes different forms, for different atoms ( long story to explain ). for hydrogen for example, there single electron forms a cloud of probability, with the highest probability to find him being near the nucleus. That cloud never ends, though, so there is an infinetly small chance that electrons from your body are now actually in the alpha centauri system (!)

With my humble knowledge I see a problem to describe the wavelike features of a graviton according to the de-broglie equation, because the wave's frequency is a function of the particle's mass. But do gravitons have mass? I don't think so.

	09-01-2003 23:51									#26
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	09-01-2003 23:53									#27
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and this helps out human civilization how?

	09-01-2003 23:56									#28
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don't be an ignoramus, Sava. almost all theoretical science leads better technology.

'electricity- and this helps human civilization how?'

	10-01-2003 00:00									#29
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I understand, it doesn't mean I want to understand though

I never did get on well with all that quantum stuff, did some for the chemistry options in my degree, but bleh to quantum...

	10-01-2003 00:16									#30
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I find it cool. I would have done physics if I had a chance to work in cosmology or as a nuclear physicist. sadly I didn't. I wanted to go to biochemistry to cure cancer, and stop aging. The army didn't let me. Now I am in Chemistry, to make better Shampoos. I envy you, Richard. ( OMG, I don't believe I've just said it.... j/k )