MORE than 400 years after Galileo reputedly dropped two cannonballs from the Leaning Tower of Pisa, French scientists are planning to recreate the experiment in space—and hoping to prove him wrong.
Galileo showed that the two balls would land at the same time, despite having different masses. Whether the story is true or not, this understanding eventually led to Einstein’s equivalence principle: gravity and acceleration have an equivalent effect on mass. This principle underlies the general theory of relativity.
The space-based experiment, called MICROSCOPE will be launched by ESA in 2004 to test this principle much more accurately than…
