So, what’s it all about, GP-B? The mission’s ultimate goal is to prove (yet again) Einstein’s Theory of Relativity – only a part of it that’s actually never been tested at all. The most common and commonly studied effects of relativity occur when a stationary observer watches a speeding object that moves at close to the speed of light. The speeding object seems to elastically stretch, become more massive, and mark the passage of time more slowly as measured by the stationary observer. This has been observed so many times, mostly from observations of sub-atomic particles, that it is now a critical bedrock component of our physics despite its inherent strangeness. Just how critical? Well, Slim Pickens may have rode one American bomb down to its target in Dr. Strangelove, but in a very real sense Albert Einstein rides them all down these days. So-called “smart bombs” have onboard computers that apply a vital relativity correction factor to satellite GPS readings to insure they hit, say, a specific window in downtown Baghdad instead of some desolate piece of worthless desert…the difference between the two being…er…nevermind.
Anyway, besides the so-called dilation of distance and mass and time, Einstein predicted yet another relativity effect. To oversimplify a bit, he predicted that if you orbited a planet long enough, your perception and definition of which way was “north” would become different compared to that of someone who was stationary on the planet. This effect is called “frame dragging” and is expected to be so miniscule that it never has been or even could be observed – until the technology to build Gravity Probe B came along.
That technology was twenty years in development before the first piece of metal was ever cut for the actual spacecraft, and it is a technology laced with incredible superlatives achieved at very great and often unexpected expense. Everything about GP-B is an engineer’s dream – or nightmare. Gravity Probe B will basically put a couple of ping-pong balls in polar orbit around Earth and start them spinning with their axis of rotation pointed at a certain star. Sounds simple. Ha, ha, ha. In the entire known Universe, the only thing more perfectly spherical than a GP-B ping-pong ball is a neutron star, and the ability to make that statement didn’t come cheap. These ping-pong balls are SO perfectly spherical, SO perfectly balanced, SO perfectly pointed towards the target star, SO perfectly spun, SO perfectly isolated from all possible outside interferences, that only Einstein’s predicted frame-grabbing can disturb them. If it exists.
And therein lies the inherent paradox of Gravity Probe B. Everybody has been lulled into believing that Einstein nailed the theory of relativity – hey, the “smart bombs” work – and so everybody is expecting that the existance of frame-grabbing is going to be a slam-dunk, too. NASA and most physicists are so sure there’s no surprises that writing off decades of labor and cash, forgetting about four blown fuses, and saving a few paltry tens of millions in the current budgetary environment looks pretty tempting. But if that thing shows frame grabbing is different than what we expect…or doesn’t even exist at all…well, it would be the Ultraviolet Catastrophe of the 21st Century, and what’s THAT worth?