Breakthrough: FIRST IMAGE OF A BLACK HOLE AND ITS EVENT HORIZON (in Messier87, April 10 2019)As scientists know, most “active” galaxies house “supermassive black holes” right in their centers, and thought to be their gravitational engines; but up to now black holes had only been detected indirectly, sometimes by the curving of the light of a galaxy (reaching us) when a black hole passes in front of it -- and creating an apparent ring or gravitational lensing --, or by the jets they emit, mostly gamma rays.
On April 10, 2019, was published the first image of a supermassive black hole surrounded by its event horizon, the one set at the center of Messier 87, a large elliptical galaxy in the constellation of Virgo (part of our neighboring Virgo Galaxy Cluster). The ring shape on this image is “the bright emissions from the hot gasses immediately surrounding the colossal maw of a supermassive black hole’s event horizon” explains the Perimeter article.*
This supermassive black hole has a mass of 6.5 billion Suns, is ½ light-day across, and is 55-million light-years away. To give an idea of its gigantism, our own supermassive black hole in the center of our galaxy the Milky Way -- called Sagittarius A*, or Sgr A* for short – is 2.6 million solar masses, thus about 2500 times less massive.
(see image: Sagittarius A*, image taken with NASA's Chandra X-Ray Observatory. Ellipses indicate light echoes. Full-field is 12.5 arcmin across.)
It took almost two decades to create the EHT - the Event Horizon Telescope - a network of radio telescopes around the world that creates an Earth-sized virtual telescope; EHT uses Interferometry to combine images taken from widely distant observatories distributed all over earth, to gain a higher resolution picture.
Avery Broderick (professor at the University of Waterloo, associate faculty member at Perimeter Institute for Theoretical Physics, Cambridge, UK), is one of the key scientists and theorists of the project. The University of Waterloo’s News release, said about these black holes, referring to him, “This first image is undeniable proof of their existence and is a robust test of general relativity in the most extreme gravitational environment known, added Broderick. ‘A black hole is a gravitational feature that comes right out of Einstein’s theory of general relativity, first described over a century ago and implicated – but never proven – to exist. Until now.’” (https://uwaterloo.ca/news/news/first-image-black-hole-captured) Broderick disclosed that their next target was to be our own supermassive black hole, Sgr A*, as well as tracking the dynamics of these two.
“We now have exceptionally strong evidence for the link between supermassive black holes and the centres of active galaxies – this is how black holes shape our universe on galactic scales,” said EHT project director Sheperd S. Doeleman.* See https://insidetheperimeter.ca/black-hole-breakthrough-astronomers-release-landmark-image/
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