This rapidly growing black hole is 500 times bigger than the one in our galaxy

An international team of astronomers, led by astronomers at The Australian National University (ANU), have discovered a rapidly growing black hole which consumes the equivalent of one Earth every second and is 500 times bigger than the black hole in our home galaxy - the Milky Way.

Dubbed the fastest-growing black hole of the last nine billion years, it has the mass of three billion suns and shines 7,000 times brighter than all the light from our own galaxy, making it visible to well-equipped backyard astronomers. According to the researchers, other black holes of a comparable size stopped growing so quickly billions of years ago.

Led by Dr Christopher Onken, the team describes the rapidly growing as a "very large, unexpected needle in the haystack".

"This black hole is such an outlier that while you should never say never, I don't believe we will find another one like this. We are fairly confident this record will not be broken. We have essentially run out of the sky where objects like this could be hiding," said co-author Associate Professor Christian Wolf.

With a visual magnitude of 14.5 - a measure of how bright an object appears to an observer on Earth - the black hole is visible to anyone with a decent telescope in a very dark backyard.

Samuel Lai, co-author and ANU PhD researcher, said, "It is 500 times bigger than the black hole in our own Galaxy. The orbits of the planets in our Solar System would all fit inside its event horizon - the black hole's boundary from which nothing can escape."

The research has been published in the arXiv database and submitted to Publications of the Astronomical Society of Australia.