On Thursday, astronomers announced the first observations of the effect of a black hole’s gravitational redshift — light coming from a star in the gravitational field near a black hole looked redder than it would’ve outside the black hole’s influence.

The black hole responsible was Sagittarius A* (pronounced “Sagittarius A-star�), the supermassive black hole at the center of our Milky Way galaxy. Astronomers think that most large galaxies like the Milky Way should have supermassive black