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Testing Relativity
MGDruss writes "NASA are proposing an empirical measurement on the ISS which would test general relativity to a precision within the bounds of superstring (and other) theories to predict deviation." We mentioned the Cassini experiment last year.
Thus sayeth the article:
" LATOR would measure this deflection with a billion (109) times the precision of Eddington's experiment and 30,000 times the precision of the current record-holder: a serendipitous measurement using signals from the Cassini spacecraft on its way to explore Saturn."
AND
"The 0.02 as accuracy of LATOR is good enough to reveal deviations from Einstein's relativity predicted by the aspiring Theories of Everything, which range from roughly 0.5 to 35 as. Agreement with LATOR's measurements would be a major boost for any of these theories. But if no deviation from Einstein is found even by LATOR, most of the current contenders--along with their 11 dimensions, pixellated space, and inconstant constants--will suffer a fatal blow and "pass on" to that great dusty library stack in the sky."
So in other words they think that taking the measurements with 30,000 times the precision of the current measurements is enough to show if the current flock of string theories is plausable.
Every wrong attempt discarded is a step forward - T. Edison
You're probably referring to Occam's Razor. One way of expressing that principle is that if two theories completely and correctly explain a phenomenon, the simpler one is preferred. If you think the simplest explanation is always correct, you're liable to believe that me when I say "apples fall towards the Earth because that's where you plant them" or "the Earth was created 5000 years ago". There's more to truth than simplicity.
Gates' Law: Every 18 months, the speed of software halves.
Thank you for playing.
Scientists, _know_ that Quantum Mechanics and General Relativity are inconsistent with each other. It is believed that both are basically special, simplified cases of a more encompasing theory - and that neither can be 'built' on to agree with the other the way you suggest.
Note that that this doesn't mean that either theory is completely wrong within the boundaries of their frameworks. Just as it's perfectly acceptable to design an everyday building or car or airplane using Newton's law of gravity, NASA put those satellites into orbits using General Relativity and design the lasers on them using ordinary Quantum Mechanics.
Check The Official String Theory site if you're confused about all these concepts. When you've done that, you will have gained some answers, but will of course get even more questions. :-)
Beware: In C++, your friends can see your privates!
It's not so much that Einstein's relativity is wrong so much that it's incomplete. General relativity (and special relativity) have passed with flying colors every test we've ever put them to. Quantum field theory (the framework of particle physics) has done at least as well (in fact, it predicts some numbers in nature to more than 10 decimal places - far better than general relativity!). These theories are GOOD - they give the right answers. The problem is that both are incomplete in some way we don't quite understand. There are fundamental problems with making a quantum field theory of gravity - the two frameworks are very different, and they don't play well together. I wouldn't say that either is "wrong", they're just both incomplete. Both theories are probably nearly-perfect approximations to some sort of underlying framework (for example, string theory). Since neither theory can be the whole story, we expect that when we impose difficult enough tests on either one, they will begin to break down slightly - the world won't quite do what the theory seems to say. This is an excellent way to look for clues as to how these two frameworks fit together. You can look at this as an extension to relativity or a replacement for it.
Loop quantum gravity predicts that space comes in discrete lumps, the smallest of which is about a cubic Plank length, or 10^-99 cubic centimeter. Time proceeds in discrete ticks of about a Plank time, or 10^-43 second. The effects of this discrete structure (non-continuous) might be seen in experiments in the near future. One of these will be measuring radiation from distant gamma-ray bursts. These occur billions of light-years away and emit a huge amount of gamma rays within a short span. According to loop quantum gravity, each photon occupies a region of lines at each instant as it moves through the spin network that is space. The discrete nature of space causes higher-energy gamma rays to travel slightly faster than lower-energy ones. The difference is tiny, but its effect steadily accumulates during the rays' billion-year voyage. If a burst's gamma rays arrive at Earth at slightly different times according to their energy, that would be evidence for loop quantum gravity. The GLAST satellite, which is scheduled to be launched in 2006, will have the required sensitivity for the experiment. Recommend the cover story of this past January's Scientific American. Also an online pdf giving more technical details is available at http://arxiv.org/ftp/physics/papers/0108/0108026.p df