Taking an image of Sgr A* at 27,000 light-years away from Earth is akin to taking a photo of a single grain of salt in New York City using a camera in Los Angeles. This is the second-ever image taken of a black hole in 2019, the EHT collaboration released an image of a black hole named M87*, at the center of the more distant Messier 87 galaxy. The new EHT image of Sgr A* shows that the 4 million solar masses are constrained within a diameter smaller than Mercury's orbit, providing clearer evidence that the object is indeed a black hole. The discovery earned Ghez and Genzel-together with Roger Penrose of the University of Oxford for related advances in the understanding of black holes- the 2020 Nobel Prize in Physics. So far, the most convincing evidence that Sgr A* is a supermassive black hole has been provided by Caltech alumna Andrea Ghez (MS '89, PhD '92) of the University of California, Los Angeles, and Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics in Germany and University of California, Berkeley, whose work revealed that Sgr A* is a compact object that has a mass nearly four million times that of the sun. (Katie) Bouman, He Sun, Junhan Kim and Aviad Levis

Black hole photo