Einstein proved right on gravity

[Oceans11]

I always thought that gravity couldn't be measured, and if it didn't exist on earth we wouldn't know about it because it doesn't fit into any theories.
And if you travel at the speed of light, time stops...

Anyway, enough babbling...

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The speed of gravity has been measured for the first time, revealing that it does indeed travel at the speed of light.
It means that Einstein's General Theory of Relativity has passed yet another test with flying colours.

The measurement was made by Ed Fomalont of the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, and Sergei Kopeikin of the University of Missouri, in Columbia, both US.

Writing in New Scientist magazine, they say: "We became the first two people to know the speed of gravity, one of the fundamental constants of nature."

Higher dimensions

Isaac Newton believed the influence of gravity was instantaneous. Later, Albert Einstein assumed it travelled at the speed of light and built his 1915 General Theory of Relativity around that assumption.

If gravity travelled at the speed of light it would mean that if the Sun suddenly vanished from the Solar System, the Earth would remain in orbit for about eight minutes - the time taken for light to travel from the star to our planet. Then, in the absence of gravity, Earth would move off in a straight line.

Modern researchers say that knowing the speed of gravity is important in the study of branches of cosmology where the Universe has more spatial dimensions than the usual three.

Some of those theories suggest that gravity could take a short cut through higher dimensions and so appear to travel faster than the speed of light.

Jupiter's help

To measure gravity's velocity, Kopeikin determined that it could be determined with the help of the planet Jupiter, if its mass and velocity were known.

The perfect opportunity arose in September 2002, when Jupiter passed in front of a quasar - a distant, very active galaxy - that emits radio waves.

Fomalont and Kopeikin combined observations from a series of radio telescopes to measure the apparent change in the quasar's position as the gravitational field of Jupiter bent the passing radio waves.

From the observations the researchers determined that that gravity does indeed move at the same speed as light.

The results of the study have been presented to this weeks meeting of the American Astronomical Society (AAS) in Seattle.

http://news.bbc.co.uk/1/hi/sci/tech/2639043.stm

 

[BigGamesOnly]

This is interesting eek. I've heard this was a hotly debated topic.

On another note, there are forces that have been found to travel faster than the speed of light. One example is the patterns that form in a thin layer of oil. The speed in which they form the pattern happens faster than the speed of light.

I look forward to hearing more from you.

 

[Oceans11]

Originally posted by BigGamesOnly:
This is interesting eek. I've heard this was a hotly debated topic.

On another note, there are forces that have been found to travel faster than the speed of light. One example is the patterns that form in a thin layer of oil. The speed in which they form the pattern happens faster than the speed of light.

I look forward to reading your thesis on oil puddles in American scientific weekly.

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Faster than the Speed of Light
Q: My physics teacher said that it is imposible to go faster than the speed on light, but if you were standing on a train going at the speed of light and you walked from one end of the train to the other, then would'nt you be going faster than the speen of light relative to the ground? and what would happen if you were going at the speed on light or faster? Theoretically

Daimhin (age 17)
Unley High School
Australia


A: Daimhin -

You're right that theoretically that is what seems like should happen. The problem with physics is that it doesn't always work the way that it seems like it should. This is an issue that perplexed Albert Einstein a great deal - it's also part of what made him so famous.

You've probably learned that the speed of light is a constant (c). But what if you looked at it from different points of view? For instance, if you're standing on the Earth, then the speed of light is c. But what if you're standing on the train that's moving at the speed of light? Shouldn't it look like the light is standing still? Well, for all that it certainly seems like it should, it doesn't. The light moves at the same speed whether you're standing on the Earth, or on a speeding train.

But whoa! How can the light move at the same speed from the Earth's perspective as from the train's? Because velocity is equal to distance divided by time, and distance and time aren't changing. But are they? According to the study of special relativity (Einstein's work), distance and time don't work the way that we think they do either. At least not when you're talking about speeds close to the speed of light.

I know that this isn't exactly what you were asking, but I wanted to emphasize to you how things don't always happen according to the rules that you're used to. The problem with going faster than the speed of light isn't so much with going that fast. Instead, the problem is with getting yourself sped up that much.

We're currently going quite slowly compared to light. But let's say you went up in a very fast rocketship that could take you close to the speed of light (with respect to the Earth). Another thing that doesn't work the way most of us would like to think that it does is mass. The closer to the speed of light you are, the more massive you become. So when you're on a ship going close to the speed of light, your mass becomes incredibly high. And the very instant before you reach the speed of light, your mass becomes infinite.

So how much energy does it take to get from there to the speed of light? Well, energy is proportional to mass. So to get the rest of the way to the speed of light, it would take an infinite amount of energy, something that even Einstein couldn't come up with. If you can't get to the speed of light, you can't get past the speed of light. Hence the statement that it's impossible to go faster than the speed of light.


http://van.hep.uiuc.edu/van/qa/section/New_and_Exciting_Physics/Relativity/20010513103853.htm

 

[jointpleasures]

Stupid ass physics teachers had not figured this out until now? Government employees, what else would you expect.

 

[PatPatriot]

Dosen't take an Einstein to figure out you can't piss up a rope.

 

[JudgeWapner]

Pat,if you have enough beers you can.

 

[DarrylParsons]

Just to clarify...it is impossible to prove anything right in physics. All we can do is show that observations up to now match up with theory. This does not mean they will always do so. Newton's theory has been "proven right" for hundreds of years until it was proven wrong by Einstein. Also, Einstein has been "proven right" and then proven wrong by quantum theory.