What is Black Hole?
A black hole is a region of space from which nothing, not even light, can escape. It is formed as the result of the collapse of a massive star. The term Black hole is a misnomer as they do not have any holes. It consist of a huge amount of matter packed densely into a small area, giving it an immense gravitational pull. The boundary of region from which no escape is possible is called the event horizon.
Since no light can escape, black holes are invisible. However, space telescopes with special instruments can help find black holes.
Black holes were first predicted by the legendary scientist Albert Einstein. He had first predicted their existence on the basis of his new theory of gravity, the general theory of relativity, in 1916. But the term ‘black hole’ was first coined by astronomer John Wheeler in 1967.
Cygnus X-I was the first detected black hole in 1964. This Black Hole is estimated to be about the size of three Suns. Sagittarius A*, M87 and Centaurus A are some of the famous black holes. It is believed that the central object of Milky Way Galaxy is a black hole.
The First Image of Black Hole Released
The scientists of the international collaboration, the Event Horizon Telescope (EHT) project unveiled the first ever image of a Black hole on 10th April 2019 at the headquarters of the European Commission.
The image is of the black hole located at the centre of Messier 87, a massive galaxy in the constellation of Virgo. This black hole is located 55 million light-years from Earth and has a mass 6.5-billion times larger than our sun.The stunning image looked like an uneven gold ring, heavier at the lower end than the upper.
How EHT took the image of a Black Hole?
EHT is a global network of eight telescopes that had been attempting to capture the first photograph of a black hole ever. For producing the image of a black hole, a huge earth-sized telescope was necessary. But instead of setting up such a huge single telescope, a fleet of the most powerful radio telescopes was assembled in various parts of earth –Hawaii, Arizona, Chile, Mexico and Spain, and at the South Pole — and synchronized these to form an array called a Very Large Baseline Interferometer. The basic concept is to combine the signal strength of the observatories on different corners of the globe to form an array as wide as Earth itself. At least 200 people from 40 different countries participated in the project.