Milky Way Center Sagittarius A* SuperMassive black hole Discovery
Reinhard Genzel - The Nobel Prize in Physics 2020, for his research on black holes - Born: 24 March 1952, Bad Homburg vor der Höhe, Germany - Affiliation at the time of the award: Director at the Max Planck Institute for Extraterrestrial Physics, Garching, Germany; University of California, Berkeley, CA, USA - Prize motivation: “for the discovery of a supermassive compact object at the centre of our galaxy”, also the 2008 shaw prize in astronomy with a $1M award
Reinhard Genzel studies infrared and submillimetre astronomy. He and his group are active in developing ground- and space-based instruments for astronomy. They used these to track the motions of stars at the centre of the Milky Way, around Sagittarius A*, like moths around a flame and show that they were orbiting a very massive object, now known to be a SuperMassive black hole with a mass of 4.100 (± 0.034) million solar masses becoming a singularity. Genzel is also active in studies of the formation and evolution of galaxies.
Genzel is the director of the Max Planck Institute for Extraterrestrial Physics in Germany, with his team they used the Very Large Telescope in Chile to observe stars orbiting Sagittarius A*, using a technique called speckle imaging to improve the quality of their images by stacking many short-exposure pictures of stars together. It took Genzel and his team nearly 10 years to develop an infra red telescope capable of seeing enough detail through the clouds of dust and gas surrounding the galactic center, it took them a further thirteen years of painstaking observations before they saw the thing they were looking for, a star orbiting exceptionally close to a massive center.
Reinhard Genzel: The image is a nice result and a wonderful confirmation of our ultra-precise observations in infrared light. From the orbital motion of stars around the black hole Sagittarius A*, we determined its mass to an accuracy of 0.1% and its distance from Earth to an accuracy of 0.2%. From this, we deduced that the shadow of the black hole must have a radius of 26 microarcseconds. The size of the shadow measured by EHT colleagues agrees quite well with this prediction when taking into account the measurement errors. The event horizon of the object has a radius of 10 microarc seconds; this angle corresponds to a one-euro coin on the moon. This value also agrees quite well with the model of a black hole with the mass of four million suns determined by the VLT and Keck teams. According to relativity theory, there is a point with infinitely high density where space-time is no longer defined. This singularity is not accessible, and I don’t see how it could ever be studied now or in the future. I must therefore pass on this problem.
The Sagittarius A* SuperMassive black hole at the center of the Milky Way galaxy has a diameter of about 24 million kilometers. The distance from the center of Sagittarius A* to its event horizon is 12 million kilometers, which is known as the Schwarzschild radius, I have used a 1.4 SUN diameter sphere into the 24 diameter EVENT HORIZON sphere and calculated that you can fit 7,238 / 1.44 = 5,026 suns into the event horizon sphere, I can also use 24 / 1.4 = 17.14, and 17.4 cubed = 5,268 Suns,, but the EVENT HORIZON sphere has the mass of 4,100,000 suns inside that forms a singularity and it is infinitely small and infinitely dense. The black hole's shadow diameter is about 58 million kilometers, and it would fit inside a ball that could hold a few million Earths.
Milky Way Center Sagittarius A* SuperMassive black hole Discovery - The story of the findings and explanation by Prof Reinhard Genzel.
