Cassini Experiment Confirms General Relativity

MikeZilla writes "An experiment by Italian scientists using data from NASA's Cassini spacecraft, currently en route to Saturn, confirms Einstein's theory of general relativity with a precision that is 50 times greater than previous measurements."

Comments

Cute, but

[CheshireCatCO]

Nice measurement, no doubt. But the article is a bit misleading. This isn't the most precise measurement of GR, just the most precise mesurement of this prediction. It sounds like they got this measurement to an error of one part per fifty thousand. If memeory serves, the measurements of the orbit on pulsar 1933+16 (the one that netted Taylor and Hulse the Nobel Prize about a decade ago) are precise to one part in something lik ten to the eleventh. And they agree with GR.

One some level it amazes me that GR passes every test we throw at it with such flying colors. On another level, I agree with Albert: the theory is too beautiful *not* to be true.

Re:Theory

[Narchie Troll]

That's not really true. "Law" is something of a layman's term. In mathematics and science, there are no absolute facts, just postulates and theorems. General relativity is basically identical to Newton's theory of gravity in basic situations, but it differs when you're working with high speeds and large scales. In fact, Newtonian physics is proven wrong for many planetary-scale gravitational effects.

It's a "law" because it seems immovable to us.

Re:Theory

[Alsee]

What a lot of people don't seem to know is that the fact that it is still called the 'theory' of relativity means that it hasn't been accepted as gospel by scientists yet.

That's not a very good description of the situation.

Contrast this with the 'law' of gravity, which has.

Actually the 'law' of gravity have been proven incorrect. It has been superceded by relativity. The common usage of 'theory' and 'law' don't quite match up with the scientific usage :)

According to the "law of gravity" the results from this measurement should have been zero. Relativity says the value isn't zero, and the value given by relativity is at least a 99.998% match for the measured value. The remaining 0.002% doesn't indicate a problem with relativity, it is just the limit of the accuracy of devices they used to make the measurement.

Relativity has been challenged with the most stringent scientific testing ever devised in countless ways. Actually part of the "problem" is that relativity is "too good". Absolutely everything it describes it does so with unbelievable accuracy. The irony is that you can't learn anything new when every single measurements exactly matches your predictions. It leaves them without anything to grab on to to try to explore the things that relativity doesn't explain.

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