This is an amazing experiment being run by NASA in order to experimentally test Einstein’s general theory of relativity. The probe is a finely-tuned gyroscope floating freely (!) within a larger satellite with a telescope attached to the main body that is aimed at a distant star to retain a set axis on which the gyroscope would spin, were it to not affected by the earth’s presence as per general relativity. The drift in the gyroscope’s axis of rotation over a year will test the following general-relativity-predicted effects:
- The geodetic effect—the amount by which the Earth warps the local spacetime in which it resides.
- The frame-dragging effect—the amount by which the rotating Earth drags its local spacetime around with it.
So cool! It’s amazing that we can actually even try to detect the effects of general relativity around the Earth; as the linked page explains, the effects being sought are the definition of infinitesimal! I am blown away by this kind of stuff.
[via crooked indifference]