For a long time it was suspected, but now there is solid evidence, via a set of images, that the supermassive black hole (SMBH) — dubbed Sagittarius A* and pronounced A star — is present in our galaxy's midst.
Previous research calculated that this ‘monster’ black hole could be about 4 million times the mass of the Earth’s sun and located about 25,000 light-years away from our planet.
As the name suggests, SMBHs contain a million times more mass than a regular stellar black hole, though only a handful of them have been confirmed in-between large galaxies. It has not yet been exactly identified how supermassive black holes form, but scientists predict that they could originate as a result of the collapse of massive gas clouds during galaxy-formation.
It’s True, Sgr A* Lurks in Our Galaxy’s Midst
A team of astronomers, studying the Milky Way, have observed that the huge and stunning cosmic body, Sagittarius A* (or simply, Sgr A*) is drawing blobs of gas into its center at the rate of 30% of the speed of light.
The European Southern Observatory in Chile (i.e., the site of the finding) has stated that this is the first time ever such material has been keenly observed so close to a black hole.
Now, locating material near the ‘event horizon,’ or the region immediately around a black hole, is considered rare because it is believed that nothing can escape from here, neither light nor matter. Also, black holes are dense thus they have a high gravitational pull and suck in anything in areas surrounding them.
But, there is a point just outside the event horizon known as the innermost stable orbit. Here, matter can exist without being drawn into the black hole. It is reported that the flares (seen by ESO as a result of this finding) originated here.
The results of the study have been published in the latest issue of the Journal of Astronomy and Astrophysics.
What GRAVITY’s Data Revealed
The paper describes the detection of positional and polarization changes and orbital motion, as flares, near the black hole Sgr A*, with the help of a near-infrared instrument called GRAVITY-Very Large Telescope Interferometer (VLTI). Interferometry is a specialized technique that combines light from different telescopes and is considered a more sensitive and precise method of making observations and calculations in space.
Among others, three bright flares were reported and believed to be a result of friction, gravity and heated gases near the orbit of Sgr A*, and their interactions with the surrounding magnetic fields.
A visual simulation created by ESO, based on the data collected by GRAVITY, of the gas clouds and flares. (Source: Gfycat)
Noted astrophysicist, Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics (MPE), called this a “major breakthrough” and also said, “We have observed the galactic center by using four telescopes as a gigantic single telescope with an effective 130-meter diameter to make interferometric images about a thousand times fainter than what has been done before.”
Similarly, Oliver Pfuhl, also a scientist at MPE, referred to this observation as “mind boggling.” Additionally, he commented on the detail and precision provided by GRAVITY for this purpose.
In May 2018, GRAVITY also helped researchers measure the light emitted by S2, when it was closest to the super-powered gravitational field of Sagittarius A*, during the star’s 16-year orbit.
Astronomers at the European Southern Observatory (ESO) in Chile used the GRAVITY instrument to obtain pictures of the supermassive black hole in the center of the Milky Way. (Source: ESO/YouTube)
The distance of this black hole is yet debatable, as astrophysicist Tana Joseph told Business Insider, “If you were close enough to observe these flares, you'd be in a lot of trouble. We would see extremely bright flashes of optical light, and there would be lots of high energy radiation, like gamma rays and X-rays, that would be very damaging to our bodies.”
The group of astronomers and scientists of this study called this one of their “dream projects” and were overjoyed that it came to close to fulfillment quicker than expected.
Top Image: Artist’s impression of shifting coronas and X-ray flares encircling the supermassive black hole. (Source: NASA/JPL Caltech)
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