Dark clouds nearly cover a partial solar eclipse.
Clouds can block out and ruin the total solar eclipse.
  • Humans have been studying total solar eclipses for millennia to better understand the cosmos.
  • Total eclipses have helped prove Einstein's theory of relativity and led to the discovery of helium.
  • Here are seven instances where total solar eclipses have helped advanced our grasp on science.

On April 8, millions of people across the US will all do the same thing: look up.