For the first time ever, astronomers have observed visible light in a black hole. And by “visible” they mean the light could even be seen by amateur astronomers with moderate-sized (20 cm/8 inch) telescopes. Is it OK to look directly into a black hole? Anyone? Bueller? Hawking?
By definition, a ‘black hole’ is a spot in space – most likely a dying star – where the gravitational pull is so strong that not even light can get out. That means they‘re invisible to anything but special telescopes that detect gravitational interactions with the area around them. Which is why researchers at Kyoto University in Japan were shocked to see light coming from V404 Cygni.
V404 Cygni is a black hole 7,800 light-years away from Earth in the Cygnus constellation (the Swan). According to their report in the current edition of the journal Nature, astronomers began watching V404 Cygni in June 2015 when it suddenly became active after 26 years in dormancy. During a two-week period, V404 Cygni emitted X-rays followed by flickers of visible light lasting anywhere from 100 seconds to 150 minutes.
What caused this first time ever black hole illumination? V404 Cygni has a companion star (smaller than the sun) that it rotates with every six-and-a-half days. V404 Cygni’s gravity pulled matter from this star into it, which released a visible burst of radiation.
So it’s not really light FROM the black hole but light CAUSED by the black hole pulling pieces of another star into its abyss. Still way cool. To prove this wasn’t a fluke, the astronomers pointed their telescopes at GRS 1915+105, another black hole with a companion star in the constellation Aquila (the eagle) and saw similar but dimmer lights.
So, is it safe to look directly into a black hole? That depends on how close you are. Even if you’re out of its gravitational pull, you could still get hit in the face with a cosmic belch of gases caused by the black hole swallowing stars, pieces of stars or gases. That’s according to a different report released a day later.
Astronomers using NASA's Chandra X-ray telescope looked at a supermassive black hole at the center of the spiral galaxy NGC 5195 and saw two arcs of X-rays they believe are remnants of two gas burps emitted from the black hole after it ate gases from a nearby galaxy.
Was it dangerous? Christine Jones, co-author of the report, had this to say:
This activity is likely to have had a big effect on the galactic landscape.
So check those black holes for light but watch out for the cosmic belches (a great name for a band).