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

Re:Help Me Here--some novice Questions

[deglr6328]

"It seems that, according to scientific philosophy today (and I say this as an observer, not a scientist), you still can't really believe this is _the_ truth about something. You have to keep thinking, "it might _not_ be true"."

I think basically that's right, it's just a matter of what theories we decide to keep testing to the limit to try to find any inconsistencies. For instance, when a new method of atomic mass spectroscopy is invented no one says 'hey I bet we could use this to test Dalton's theory of atoms down to the fraction of an AMU!', even though it could very well be used to do that. The reason we don't is because no one expects to find anything that would invalidate the atomic theory of elements. We know, however, that there must be something "beyond" Einstein's relativity in the same way that the orbit of mercury reveals a breakdown of Newtonian Physics. This experiment with Cassini was in a way looking for Einstein's 'Mercury problem'. The fact that it has not found any inconsistency with GR (along with countless other experiments done in the past century) is a testament to, not only our lack of tools to measure with extreme enough precision the physical phenomena effected by GR but also to the greatness of the theory of General Relativity itself. We will continue to test Einstein though, in December Gravity Probe B will be launched, using ultrahigh precision quartz sphere gyroscopes, it will be able to measure certain effects of GR to the parts per million range. Science is a search for ever greater truth.

Re:Theory

[Scarblac]

There's no difference between a "theory", a "theorem", a "law", etc in science. They're all just synonyms for theory, to give them different names. Science deals with theories. Math deals with theorems.

I've remarked before, it's only Americans that have this idea that a "law" is better than a "theory", etc.

Can someone explain to me why that is? Is this taught in schools? Is it caused by Creationists (another US phenomenon) trying to muddy the waters by suggesting "evolution theory" hasn't made it to "law status" yet?

Re:Theory

[00420]

I've remarked before, it's only Americans that have this idea that a "law" is better than a "theory", etc.
Can someone explain to me why that is? Is this taught in schools?

Yes. I was tought this in middle school. I was told the steps of the Scientific Method were:
1. Observe
2. Hypothosize
3. Experiment
4. Theory
5. More experiments
6. Law

Not only that but I was told that in order for something to become a law it had to hold up 100% of the time!

I was quite suprised when I got to college and learned that this was not true.