Sun-like star co-orbiting with black hole Gaia BH1 is a Sun-like star co-orbiting with a black hole estimated at 10 times the Sun's mass. (ESO/L. Calcada) In 1916, Karl Schwarzchild theorized the existence of black holes as a resolution to Einstein's field equations for his Theory of General Relativity. By the mid-20th century, astronomers began detecting black holes for the first time using indirect methods, which consisted of observing their effects on surrounding objects and space. Since the 1980s, scientists have studied supermassive black holes (SMBHs), which reside at the center of most massive galaxies in the Universe. And by...