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NASA Gravity Probe Launched
ping pong writes "Forty-five years in the making and 24 hours late, NASA launched the $700 million satellite into orbit today to test Albert Einstein's general theory of relativity. The satellite, which was inserted into a polar orbit, will spend two months getting ready, then 16 months making measurements." NASA's mission news has more.
The most facinating tidbit from the NASA article is the absoutely beyond perfect Niobium-coated Quartz spheres at the heart of the ultra-precise gyroscopes.
A quick Google found this link with more cool details, including:
* The 1.5-inch diameter rotors are within 40 atomic layers (0.3 millionths of an inch) of a perfect sphere.
* "Electrical sphericity" must be held to parts in ten million.
* Each rotor spins inside a quartz housing with clearances to the rotor of barely one thousandth of an inch.
* To lift the rotor on earth takes 1,000V. In space, only a fraction of a volt is needed.
* In 1,000 years the gyroscope should barely lose 1% of its starting speed.
* To isolate the gyroscope from the Earth's magnetic field, it will be shrouded in four layers of lead balloons, plus an outer shield of iron.
Plus these cool facts (and a ton more), there are steampunk-styled drawings of the manufacturing process.
Seems like NASA could make some money selling the rejects (you know there are plenty) as the ultimate shooters!
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
Wouldn't our understanding of something as fundamental as general relativity far out weigh any kind of understanding we could gain from Mars? Not necessarily. More has been learned from putting this experiment together than will be learned from its results - it is a fine-scale test of one of the most successful theories of all time. Going to Mars, though expensive and such, could be a big deal if only as a proof of concept. Look at how much was learned going to the Moon. Going to Mars is orders of magnitude more complex - interplanetary radiation, the technological and social advances that will let a crew live together for months, getting people there and back ... if we can get to Mars and back we can go anywhere in our Solar System with trivial amounts of scaling.
And, if we do find life on Mars (or elsewhere), that is potentially the most important discovery, um, ever. It tells us things about the fundamental nature of the universe too - and, short of an experiment either detecting gravity waves or detecting an overall curvature to spacetime, there isn't that much experiments will tell us about gravity right at the moment.