Black holes emit light visible to even amateur astronomers

7 Jan 2016

A new study into a black hole 7,800 light years from Earth has shown that flashes of light beaming out of its centre are visible to owners of even modest telescopes.

Black holes are a bit mad, when you think about it. Nothing can escape them, not light, not sound, not Harry Houdini. One you get too close you get swallowed up.

When a black hole sucks in any nearby matter, be it gas, dust or even stars, it can result in what is called an accretion disk at the point of entry.

If there’s enough matter being swallowed up, these disks can produce immense amounts of heat and, ultimately, a bright glow.

No need for professional gear

But these events aren’t easy to spot and, until now, it was thought that you needed a super-duper powerful telescope to even have a chance of seeing one such occurrence.

However, according to Mariko Kimura and her colleagues in Kyoto University in Japan, that may no longer be true. Looking at a black hole in the Cygnus constellation, 7,800 light years from Earth, Kimura’s team went back through the years.

The black hole, situated in a binary system called V404 Cygni, lay dormant for a quarter of a century until a two-week long event last year. The accretion disk activity was so prominent during that spell that the black hole, for a brief time, became one of the brightest sources of X-rays in the universe.

This resulted in a flicker of light, visible to amateur astronomers with just a 20cm telescope.

Moderate telescopes

“We find that activity in the vicinity of a black hole can be observed in optical light at low luminosity for the first time,” Kimura told

“These findings suggest that we can study physical phenomena that occur in the vicinity of the black hole using moderate optical telescopes without high-spec X-ray or gamma-ray telescopes.”

The event occurred when a star got too close to V404, was stripped of its surface matter and then got swallowed up.

With the findings published in Nature, Kimura’s team reckon the light originated from the actual way the star was gradually consumed. The long, drawn-out process, they claim, is the reason behind the brightness.

Black holes are already big news in 2016 it seems. Yesterday, we reported astronomers discovering two bizarre cases in different locations with one black hole showing itself to be burping and another to be undergoing a slimming regime.

Black hole image via Shutterstock

Gordon Hunt was a journalist with Silicon Republic