An international team of scientists collaborated to find the first-ever visual evidence of a supermassive black hole in a faraway galaxy (Credit: EHT Collaboration et al 2019)

The existence of black holes, first proposed by Albert Einstein in his 1916 general theory of relativity, has been known for decades. However, astrophysicists have thus far relied on indirect evidence, such as the stars orbiting a large and invisible object in the center of the Milky Way galaxy, to prove their presence. That changed on April 10, 2019, with the release of the first-ever direct visual evidence of a black hole in the center of the galaxy M87, located 55 million light-years from Earth.