IT HAS taken almost 50 years to conceive and build and has cost more than $700 million, but now NASA’s Gravity Probe B spacecraft could be upstaged by telescopes on the ground.
The craft is designed to accurately test Einstein’s general theory of relativity. According to the theory, a gyroscope orbiting a massive object such as the Earth should experience two forces that gradually cause it to “precess”, pushing its axis of spin out of alignment. The stronger force, known as the geodetic effect, is caused by the Earth warping the fabric of space-time. The other, known as the gravitomagnetic effect, is caused by the rotating…
