Gravity Probe B - Testing Einstein's Theories

Gravity Probe B has tested- and proven,  two effects of the general relativity theory developed by Albert Einstein developed in 1916. Orbiting around the earth, the spacecraft has the perfect opportunity to measure this, as the earth itself is a large enough mass to warp space-time noticably. The sensitive gyroscopic sensors were able to prove:
"1.The geodetic effect—the amount by which the Earth warps the local spacetime in which it resides.


2.The frame-dragging effect—the amount by which the rotating Earth drags its local spacetime around with it."(GP-B Mission)
The Geodetic effect is an essential component of the General Relativity theory, as it rests upon the tenet that mass can warp space-time. This allows for the existence of black holes, quasars, and other space phenomena.
The frame dragging effect had never been tested before. It can be visualized as a ball spinning in a bowl of a thick liquid such as syrup. As it spins it drags the syrup in a spiral around it.
In theory testing relativity is a simple concept. According to GP-B Mission;
 
"1.Place a gyroscope and a telescope in a polar-orbiting satellite, 642 km (400 mi) above the Earth. (GP-B actually uses four gyroscopes for redundancy.)


2.At the start of the experiment, align both the telescope and the spin axis of each gyroscope with a distant reference point—a guide star.

3.Keep the telescope aligned with the guide star for a year, as the spacecraft makes over 5,000 orbits around the Earth, and measure the change in the spin-axis alignment of each gyro over this period in both the plane of the orbit (the geodetic precession) and orthogonally in the plane of the Earth's rotation (frame-dragging precession).

The predicted geodetic gyro-spin-axis precession is a tiny angle of 6,606 milliarcseconds (0.0018 degrees) in the orbital plane of the spacecraft. The orthogonal frame-dragging precession is a minuscule angle of 39 milliarcseconds (1.1x10-5 degrees). "
Links:
Official Site
NASA GP-B Mission
Paper model of the Spacecraft

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Sincerely, Space Cadet