For several days, the news has been burbling with hints that the first direct image of a black hole will be revealed to the public at parallel news conferences on Wednesday, concurrent with the publication of the image in a peer-reviewed scientific journal.
"When a black hole starts to suck in mass - which forms around it in what we call an accretion disk - it is this mass that starts to shine", explained Paul McNamara, an astrophysicist at the European Space Agency.
The black hole depicted in the movie "Interstellar".
The US National Science Foundation has scheduled a news conference in Washington to announce a "groundbreaking result from the Event Horizon Telescope (EHT) project", an worldwide partnership formed in 2012 to try to directly observe the immediate environment of a black hole.
The black holes are expected to appear "as a tiny shadow backlit by the glow of radio energy at the galactic center".
One news conference, at the National Press Club in Washington, D.C. will be presided over by France Córdova, head of the National Science Foundation.
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Sagittarius A* - Sag A* for short - is smack in the middle of the Milky Way, some 26,000 light years from Earth. That theory, put forward in 1915, was meant to explain the laws of gravity and their relation to other natural forces.
The EHT's other target, M87, is notable for shooting out a fast jet of charged subatomic particles that stretches for some 5 000 light years. Everything science knows about black holes is based on inference rather than actually witnessing one with our own eyes (electronic or otherwise), but that may be about to change.
The telescope is not a single instrument but a collaboration involving radio observatories around the world, including facilities in Hawaii, Chile, Europe and at the South Pole.
The images, once we see them, will have been made possible by a planet-wide network of telescopes working in unison to peer deeper into the galaxy than ever before.
The scientists also will be trying to detect for the first time the dynamics near the black hole as matter orbits at near light speeds before being swallowed into oblivion. The scientists will be looking for a ring of light - radiation and matter circling at tremendous speed at the edge of the event horizon - around a region of darkness representing the actual black hole.
Dr. Urry pointed out that evidence for the existence of black holes has mounted steadily since the 1960s, including the Nobel Prize-winning detection, in 2015, of vibrations in spacetime from two colliding black holes by the LIGO experiment. If Einstein's predictions are correct, it will permit accurate measurements of the object's size and shape. "If we find it to be different than what the theory predicts, then we go back to square one and we say, 'Clearly, something is not exactly right'".