Science a GoGo's Home Page Forums General Discussion Physics Forum Remember Gravity Probe B?

It was the Worlds most Perfect Gyroscope
Recorded In the Guiness Book of Records as the most perfect Sphere in existence.
Exceeded only by the Ultra perfect Sphere of a Neutron Star.

The Gravity probe B, experiment uses four ultra-precise Quartz Balls as Gyroscopes, to generate the data required for an unprecedented test to precisely measure two effects predicted by Einstein's theory
One test is called "Frame-Dragging", is the amount by which the rotating Earth drags local space time around with it.
The other is the "Geodetic effect", the amount by which the Earth warps the local space time in which it resides.

The Gyroscope was launched by NASA in back in 2004. Once in Space, a stream of pure helium gas was used to spin up each of the four gyroscopes to approximately 4,000 rpm.

After that, all but a few molecules of the helium spin-up gas were evacuated from the housings, and the gyroscopes were left to spin on their own—a mere 32 microns (0.001 inches) from their housing walls, free from any mechanical or fluid supports. For the the experiment, the near-perfect spherical and homogeneous rotors, combined with the highly sophisticated Gyro Suspension System, in a perfect vacuum, was expected to keep spinning for up to 15,000 years, without any other intervention!
Guess what its still spinning out there in Space today,

After 4 years of spinning in Space NASA has just released the amazing figures that Einstein was right....today!
That....local time, and gravity, is being dragged around our rotating Earth.

Read about the epic experiment of the century below:-

http://science.nasa.gov/science-news/science-at-nasa/2011/04may_epic/

That's just beautiful!

Amazing engineering.

What a great example of the power of mathematics to describe the cosmos - in this case, almost a century before it was possible to show the description to be correct.

I'd be fascinated to hear from "Einstein was wrong" people on this one.

Just one more example of the continuing series of unrelated experiments that show just how right Einstein was. Last year there was the experiment where some experimenters built 2 new atomic clocks that were much more stable than any before, which is amazing itself, and then used them to test
GR. First they set them up in adjacent rooms and carefully compared their times. Then they jacked one of them up a few inches and compared their times again. And they were different, by just the amount that GR predicted for that small change in the gravitational potential. Then they slid one of them back and forth fairly slowly. And once again their times varied according to the rules of relativity.

And then there were the Voyager spacecraft. As they approached the edge of the solar system they weren't moving the way they were expected to. So some people suggested that gravity worked differently in interstellar space. Wrong, there was just now a study that showed that the problem was due to the heat generated by the spacecraft. So once again, Einstein got it right.

Bill Gill

Possibly you are more likely to hear from the "Einstein cribbed it from someone else" people.

Careful, Bill S, many a true word spoken in jest

Actually, I was not jesting. The smiley is attached to an unspoken thought as to where such a contribution might come from.

Oh dear, just when I thought we were seeing some humour in the forum. But seriously(!) yes, I know.