Equivalence principle in space test
Since Galileo Galilei and Newton, the assumption is valid that inert and heavy mass are equivalent. This is, however, questioned by new physical theories such as the String theory. Now, the equivalence principle is put to test with so far unachieved accuracy within the scope of the "Microscope" space project - a German-French cooperation. PTB has developed the manufacturing and measuring methods for the test masses which are required for the acceleration experiments in a near-Earth orbit, and has manufactured the first test pieces. more...