Up until this May, 2019, Sagittarius A* (Sgr A*), the Milky Way’s central supermasive black hole appeared like a massive, dormant volcano, a sleeping monster, a slumbering region of spacetime where gravity is so strong that “what goes into them does not come out.”
“We’re so excited, and have been preparing for years to make these measurements,” said Andrea Ghez, who directs the UCLA Galactic Center Group. “For us, it’s visceral, it’s now—but it actually happened 26,000 years ago!” said Andrea Ghez, who directs the UCLA Galactic Center Group about photons from a star known as S0-2 that makes a complete orbit in three dimensions around the supermassive black hole at the center of the Milky Way confirming Einstein’s theory of general relativity. The full orbit takes 16 years; the black hole’s mass is about four million times that of the sun.
