A French satellite, just launched, will test a basic theory of famed physics innovator Albert Einstein that, if proven wrong, could undermine the whole foundation of physics.
The satellite, called Microscope, launched Monday, will test the concept that in a vacuum, all bodies fall at the same speed -- an idea on which Einstein based the theory of general relativity that made him famous.
The principle has been tested before, but according to the French space agency, this experiment will be more exacting than any of its predecessors. The experiment will test the idea that two objects of different weights would behave exactly the same way in a vacuum.
Aboard the satellite, two cylindrical masses -- one made of titanium and one of a platinum-rhodium alloy -- will be controlled to remain motionless. If the same force can be applied to each to keep it still, the principle is verified. If it takes different levels of force, Einstein's idea would be proven wrong, and the basic concepts of physics would have to be re-examined.
The French space agency CNES has not said when the experiment will be finished.