A black hole is a region of space-time exhibiting such strong gravitational effects that nothing and not even particles and electromagnetic radiation such as light – can escape from inside it. The theory
of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole.
The boundary of the region from which no escape is possible is called the event horizon. Although the event horizon has an enormous effect on the fate and circumstances of an object crossing it, no locally detectable features appear to be observed. In many ways, a black hole acts as an ideal black body, as it reflects no light.
The black hole itself – a cosmic trapdoor from which neither light nor matter can escape – is useable. But the latest observations take astronomers right to its threshold for the first time, illuminating the event horizon beyond which all known physical laws collapse.
The breakthrough image was captured by the Event Horizon Telescope (EHT), a network of eight radio telescopes spanning locations from Antarctica to Spain and Chile, in an effort involving more than 200 scientists.
Shepherd Doeleman, EHT director and Harvard University senior research fellow said: "Black holes are the most mysterious objects in the universe. We have seen what we thought was useable. We have taken a picture of a black hole."
To capture the image, astronomers reached across intergalactic space to Messier 87, or M87, a giant galaxy in the constellation Virgo. There, a black hole several billion times more massive than the sun is unleashing a violent jet of energy some 5,000 light-years into space.
The image offered a final, ringing affirmation of an idea so disturbing that even Einstein, from whose equations black holes emerged, was loath to accept it.
The results were announced simultaneously at the news conferences in Washington, D.C., and five other places around the world, befitting an international collaboration involving 200 members, nine telescopes and six papers for the Astrophysical Journal Letters.
