Almost a century ago, a solar eclipse revealed the geometry of spacetime. Now, physicists and amateur astronomers — armed with do-it-yourself gear — are going to double check that math during the Aug. 21 solar eclipse.
In his 1915 general theory of relativity, Albert Einstein predicted that the sun’s gravity should distort spacetime in its vicinity. Stars behind the sun would appear in different positions with respect to each other during an eclipse than they would on an ordinary night when the sun is nowhere in sight.