Reply With QuoteSpeed of gravity? Don't you just drop something from a high place and measure how fast it goes?
Chinese scientists find evidence for speed of gravity
BEIJING, Dec. 27 (Xinhua) -- Chinese scientists revealed Wednesday that they have found evidence supporting the hypothesis that gravity travels at the speed of light based on data gleaned from observing Earth tides.
Scientists have been trying to measure the speed of gravity for years through experiments and observations, but few have found valid methods.
By conducting six observations of total and annular solar eclipses, as well as Earth tides, a team headed by Tang Keyun, a researcher with the Institute of Geology and Geophysics under the Chinese Academy of Sciences (CAS), found that the Newtonian Earth tide formula includes a factor related to the propagation of gravity.
http://news.xinhuanet.com/english/sc..._132067538.htm
Speed of gravity? Don't you just drop something from a high place and measure how fast it goes?
Not really, since friction and air resistance, etc...Originally Posted by dave81
That is correlative to earth's force of gravity on an object here on earth, not the Universal force of gravity and how fast it has an impact on two different objects.
Look at it this way; say the Sun would disappear in this instance. It would take 8 minutes for us here on earth to notice that the light would have gone out, but would the earth continue revolving around the same point too for 8 minutes or would it just shoot straight out of our system?
It has theoretically been established long time before that gravity moves at the same speed as light, meaning the earth, in the previous example, would still revolve around an empty speck of space for 8 minutes before gravity lets go.
The Chineses now seem to been able to prove it 'practically'.
Has nothing to do with the topic at hand. And the force of gravity differs quite wide across our universe.
That is gravitational acceleration, not speed of gravity. Basically the experimant in the OP is about the speed of gravity, like speed of EM waves.
PS: Read the original post. I am not sure if with a relative error of 5% the experiment can be termed as conclusive.
I am no expert, but I think it is even stranger. If you had a spaceship and could warp to an other star. When you get out of warp-speed, your ship is pulled by the star, but the star is also pulled by your mass, even though to a very smaller degree. For this examle, lets say you enter the gravity field of this sun at one astronomical unit (the earth-sun-distance).
But now comes the tricky part. Do you instantly pull the sun towards you or as Einstein said, does it take eight minutes (the time the light needs to reach you from the sun and according to Einstein the fastest speed information can travel) till the sun feels your gravity?
I could of course be completely wrong as I am a lawyer, not physicist
There really is no 'gravity fields' really. The force of gravity is a very very weak force that gets more and more diluted by the distance between the two objects. There's no distinct line where an object's gravity end.I am no expert, but I think it is even stranger. If you had a spaceship and could warp to an other star. When you get out of warp-speed, your ship is pulled by the star, but the star is also pulled by your mass, even though to a very smaller degree. For this examle, lets say you enter the gravity field of this sun at one astronomical unit (the earth-sun-distance).
But now comes the tricky part. Do you instantly pull the sun towards you or as Einstein said, does it take eight minutes (the time the light needs to reach you from the sun and according to Einstein the fastest speed information can travel) till the sun feels your gravity?
I could of course be completely wrong as I am a lawyer, not physicist
In your example neither the star's force or the force from the spaceship would exist until 8 minutes after you left 'warp-speed', if the ship were to stop at a total stand still. Thereafter the star's pull (and vice verce) would start to affect the ship.
Nothing particularly surprising, but well done to them nonetheless. Even barring the existence of gravitons, my understanding is that information--whether matter or energy--can't be transmitted through space faster than the speed of light. Ignore me of course if I'm completely off-base here. I don't know much about theoretical physics beyond an amateur interest.
Found the evidence? Oh, you mean stole it!
chinese steal anything .. aprt from how to ...................
They don't steal. They make copies.
Coupled quantum particles?
Gravity .... is like Space it can be folded and your journey will be in mili secs ...
It's so easy to alter time , bend space and amongst other things ....
I believe that quantum entanglement is basically explained as being able to see the same event at two different locations, rather than information being transmitted superluminally. How exactly that prevents an information paradox from occurring...don't ask me.
Yeah. Easy.
Since nothing can go faster than the speed of light, I would think it would take at least 8 minutes (if you stay stationary).
A little off-topic... but, hey, seasch, as a lawyer, do you know what a Boeing 747 full of lawyers at the bottom of the ocean is? (Yeah, this is a joke.)I could of course be completely wrong as I am a lawyer, not physicist
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