In a first, Galileo’s gravity experiment is re-created in space | Science News

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In a first, Galileo’s gravity experiment is re-created in space

Equivalence principle holds up inside an orbiting satellite

By
6:00am, December 4, 2017
satellite illustration

FREE-FALLIN’  Scientists compared the acceleration of two objects in free fall in a satellite orbiting 710 kilometers above Earth (illustrated).

Galileo’s most famous experiment has taken a trip to outer space. The result? Einstein was right yet again. The experiment confirms a tenet of Einstein’s theory of gravity with greater precision than ever before.

According to science lore, Galileo dropped two balls from the Leaning Tower of Pisa to show that they fell at the same rate no matter their composition. Although it seems unlikely that Galileo actually carried out this experiment, scientists have performed a similar, but much more sensitive experiment in a satellite orbiting Earth. Two hollow cylinders within the satellite fell at the same rate over 120 orbits, or about eight days’ worth of free-fall time, researchers with the MICROSCOPE experiment report December 4 in Physical Review Letters. The cylinders’ accelerations match within two-trillionths of a percent.

The result confirms a foundation of Einstein

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