ROCHESTER, N.Y. — On Monday, April 8, the skies over Rochester will go dark at 3:20 p.m. as the moon casts its shadow over the entire sun during the total solar eclipse.

Solar eclipses not only leave viewer amazed but have helped to prove multiple scientific discoveries, including Albert Einstein’s theory of general relativity.

Eclipses are predictable. We know when they’re going to hit, where, and we can plan our celebrations accordingly. Eclipses also give us scientific chances we otherwise wouldn’t have, whether it’s looking at how animals react or studying the sun itself.

Jim Bader at the Rochester Museum and Science Center said that, in 1919, the eclipse helped prove Einstein’s theory of general relativity. That theory is foundational to our entire understanding of gravity and has all kinds of applications in modern technology.

Einstein developed the theory in 1915 but it was just words on paper. In 1919, it was put to the test for the first time during a total solar eclipse. The chance to look directly at the sun, something with a huge gravitational pull, was a perfect test.

A British scientist named Arthur Eddington built two observatories in the path of the eclipse so they could fact check Einstein. When Eddington’s team took photos and measurements, they found out he was right.

“This is a big deal, because this is another one of those moments where somebody did some math on a piece of paper and said this will happen, if you go and check for it,” Bader said. “Then another scientist from another part of the world, and in particular, in this specific case, this is during World War I. So you have a scientist on one side of the war saying that these things will probably happen, a scientist on the other side of the war saying I’ll check to see if that’s correct and it was.”

The theory of relativity has given us all kinds of incredible technology including the GPS. The math that decides how far away you are from something is only possible because of Einstein’s theory.