Astronomers have found evidence of a massive black hole at the heart of the Milky Way galaxy.

The hole is estimated to be one hundred times more massive than the sun.

If confirmed the black hole will be the second biggest to have been discovered in the Milky Way galaxy.

Sagittarius A, which is located at the centre of the galaxy is currently the largest, and has a mass of about 4 million suns.

The phenomenon was spotted by scientists who had been studying a huge toxic cloud swirling in the middle of the galaxy.

The gasses within the cloud were moving at an abnormal speed, leading scientists to suspect that a huge compact object was at its centre.

The scientists suspicions were further bolstered by radio waves from the middle of the cloud which were indicative of a black hole.

Observations of the phenomenon could help fill in a gap of astronomers knowledge of black holes.

Classed as an intermediate-mass black hole, the new discovery is not quite as big as a supermassive black hole, but bigger than the small black holes littered throughout the galaxy. The discovery could help scientists confirm how supermassive black holes form.

Currently the most popular theory is that smaller black holes coalesce into larger ones which come together to form supermassive black holes at the center of galaxies.

Previously there has been no evidence proving that this actually happens. The size of the new discovery could just be what scientists have been looking for all along to prove the theory correct.

Black holes are formed by large stars which have exploded, having reached the end of their life. They are not visible to the eye, but affect the way stars and gasses look around them.

There have been 60 small black holes discovered in the Milky Way, though there are an estimated 1 million in the galaxy.