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

The worlds most perfect Gyroscope
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 gyroscopes to generate the data required for an unprecedented test to precisely measure two effects predicted by Einstein's theory.
One is the geodetic effect, the amount by which the Earth warps the local space time in which it resides.
The other, called frame-dragging, is the amount by which the rotating Earth drags local space time around with it.

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, are expected to keep spinning for up to 15,000 years, without any other intervention!

Lots and lots of amazing reads of technology, plus short Videos, to keep everyone reading for days, if not weeks.

http://einstein.stanford.edu/TECH/technology1.html

http://www.nasa.gov/mission_pages/gpb/index.ht

Mike, your second link gave me a not found error. Any insight into why this is so?

(Rose, re second link: The last two letters were missing: http://www.nasa.gov/mission_pages/gpb/index.html)

What a beautiful piece of technology.

Unfortunately, the theory met some unexpected problems in practice:

http://space.newscientist.com/article/dn...dId=space_rss20 (20 May 2008)

"The probe's data was unexpectedly noisy due to solar flares in March 2005 that interrupted the satellite's observations, as well as unexpected torques on the gyroscopes that changed their orientation, mimicking relativistic effects...The noisy data meant that GPB could not measure the effects as precisely as astronomers had by firing laser beams at mirrors left on the Moon by the Apollo astronauts."