It sounds strange to describe a black hole as "bright," but astronomers at Australian National University have spotted one so bright that were it in our home galaxy, it would outshine all the stars in the sky and even give the full moon a run for its money. This supermassive monster also happens to be the fastest-growing black hole ever seen, devouring the equivalent of the Sun every two days.

This supermassive black hole sits at the center of a quasar known by the catchy name of SMSS~J215728.21-360215.1. It's estimated to have the mass of about 20 billion times that of the Sun, and is growing extremely fast, at a rate of one percent every million years.

"This black hole is growing so rapidly that it's shining thousands of times more brightly than an entire galaxy, due to all of the gases it sucks in daily that cause lots of friction and heat," says Christian Wolf, an author of the study. "If we had this monster sitting at the center of our Milky Way galaxy, it would appear 10 times brighter than a full moon. It would appear as an incredibly bright pin-point star that would almost wash out all of the stars in the sky."

In that hypothetical scenario however, there wouldn't be anyone on Earth to enjoy the light show, since the quasar is emitting huge amounts of x-rays that would sterilize the planet. Thankfully, we're nice and safe at a distance of over 12 billion light-years – which of course means that astronomers are seeing it as it was 12 billion years ago, dating it to fairly soon after the Big Bang.

"We don't know how this one grew so large, so quickly in the early days of the universe," says Wolf.

The team found this supermassive black hole by combining data from the ESA's Gaia satellite, NASA's Wide-field Infrared Survey Explorer (WISE) and ANU's SkyMapper telescope.

"These large and rapidly-growing blackholes are exceedingly rare, and we have been searching for them with SkyMapper for several months now," says Wolf. "The hunt is on to find even faster-growing black holes."

The research was published in the journal Publications of the Astronomical Society of Australia.