A black hole is an area of spacetime where gravity is so powerful that nothing can leave it, including particles and electromagnetic waves like light. Black holes are notoriously difficult to detect, with their presence being only inferred from their impact on their surroundings. This is due to the fact that black holes not only do they radiate light, but they also imprison photons behind an event horizon, making examining them directly in optical light very difficult.
Theories about Sagittarius A*(Sgr A*) and its gigantic inhabitant date back to the early 1930s, when Karl Jansky discovered a radio signal directed towards the Milky Way's core from a position in the direction of the Sagittarius constellation. Astronomers Bruce Balick and Robert L. Brown discovered the galactic center compact radio emitter Sagittarius A* in February 1974. Astronomers proposed in the 1980s that the core compact object was most likely a black hole of otherwise unbelievable scale.
Scientists released the first image of Sagittarius A*, the supermassive black hole at the center of our Milky Way galaxy, on May 12, 2022. The Event Horizon Telescope, a planet-wide array of observatories most known for catching the event horizon of a black hole in Messier 87 (M87) in 2019, provided the historic image of Sagittarius A*.
Sagittarius A* is a supermassive black hole at the center of our spiral galaxy, the Milky Way. It is pronounced, "Sagittarius A star." Sagittarius A* has a mass 4.3 million times that of the sun, according to astronomers Reinhard Genzel and Andrea Ghez.
The image was captured using submillimeter radio waves, demonstrating that a black hole exists in the Milky Way's core, devouring whatever hydrogen gas is available. After years of attempts to catch Sgr A*, which is significantly smaller than M87, the photograph represented a huge technological breakthrough.
The Event Horizon Telescope Collaboration is a multi-national scientific effort that uses a telescope to image black holes. Over 200 scientists and engineers are involved in the partnership, which uses telescopes all over the world. The name "Event Horizon Telescope" refers to the black hole's border, beyond which no radiation (including light) may escape. According to Einstein's theory of general relativity, photons cannot escape black holes.
The EHT photographed M87's event horizon in 2019, revealing the black hole's silhouette in great detail. Because the gas trapped in a swirl around the black hole produces a lot of radiation, it shows up so vividly. A follow-up mission in 2021 imaged the polarised light surrounding the black hole, revealing its magnetic fields. When light is emitted in a hot and magnetic environment, such as a black hole, it becomes polarised. The orientation and brightness of unpolarized and polarised light differ.
Sgr A* is obscured by a lot of dust in our galaxy, making it more difficult to see through all of the stuff, scientists noted, "further complicating things." "The radio waves are scattered, and the image is blurred. However, astronomers have been able to partially counteract the effects of this blurring thanks to years of observations at other wavelengths."