On Wednesday, NASA released the first ever photograph of a black hole and its shadow. The photograph was captured by an international network of radio telescopes called the Event Horizon Telescope (EHT).
Why was a black hole never photographed before? By definition, a black hole is a region in space where the pulling force of gravity is so strong that neither matter nor light can ever escape. For anything approaching a black hole, the point of no return is called the “event horizon”; anything that comes within the event horizon will be consumed forever. Because no light can escape from it, a black hole is invisible. Follow updates
However, advanced space telescopes can identify black holes by observing the behaviour of material and stars that are very close to black holes.
This hot disk of material encircling a black hole, as NASA explained, shines bright. And against this disk, a black hole appears to cast a shadow. This is how the photograph of the black hole was achieved.
The image released shows the shadow of a supermassive black hole in the centre of Messier 87 (M87), an elliptical galaxy some 55 million light-years from Earth. This black hole is 6.5 billion times the mass of the Sun. Catching its shadow involved eight ground-based radio telescopes around the globe, operating together as if they were one telescope the size of our entire planet, NASA said in a statement.
Einstein’s general theory of relativity predicts how spacetime is warped by the extreme mass of a black hole. ‘Science News’ magazine reported that the image aligns with expectations of what a black hole should look like based on that theory.