Read the whole article for the details; basically, three groups of scientists are trying to find a very small deviation from the Equivalence Principle (which states that gravity affects all materials equally) that would support various forms of String Theory. These experiments need to be extremely accurate (to within at least one part in 10 trillion (10[sup]13[/sup]: the experimenters claim they'll detect deviations up to 1 quintillion (10[sup]18[/sup]), 1 quadrillion (10[sup]15[/sup]), and 100 quadrillion (10[sup]17[/sup])); and if a deviation is indeed found, String Theory would see some much sought-after experimental support. These are exciting times in theoretical physics; we may be a step closer to the Grand Unified Theory.
"Some variants of string theory predict the existence of a very weak force that would make gravity slightly different depending on an object's composition," says Will. "Finding a variation in gravity for different materials wouldn't immediately prove that string theory is correct, but it would give the theory a dose of supporting evidence."
This new facet of gravity, if it exists, would be so astonishingly weak that detecting it is a tremendous challenge. Gravity itself is a relatively weak force—it's a trillion trillion trillion (1036) times more feeble than electromagnetism. Theorists believe the new force would be at least ten million million (1013) times weaker than gravity.
No experiment to date has detected this tiny difference. But now three groups of scientists are proposing space-borne missions that would hunt for this effect with greater sensitivity than ever before.
|
No comments:
Post a Comment