A Tour of a Black Hole Outburst Caught on Video

Astronomers have caught a black hole hurling hot material into space at close to the speed of light. This flare-up was captured in a new movie from NASA's Chandra X-ray Observatory.

The black hole and its companion star make up a system called MAXI J1820+070, located in our Galaxy about 10,000 light years from Earth. The black hole in MAXI J1820+070 has a mass about eight times that of the Sun. This makes it a so-called stellar-mass black hole, formed by the destruction of a massive star.

The companion star orbiting the black hole has about half the mass of the Sun. The black hole's strong gravity pulls material away from the companion star into an X-ray emitting disk surrounding the black hole.

Some of the hot gas in the disk will cross what is called the event horizon, or, the point of no return, and fall into the black hole. But some of it is also blasted away from the black hole in a pair of short beams of material, or jets. These jets are pointed in opposite directions, launched from outside the event horizon along magnetic field lines.

Using four observations obtained by Chandra in 2018 and 2019, astronomers were able to capture footage of this black hole's behavior.

Just how fast are the jets of material moving away from the black hole? From Earth's perspective, it looks as if the northern jet is moving at 60% the speed of light, while the southern one is traveling at an impossible-sounding 160% of light speed!

This is an example of superluminal motion, a phenomenon that occurs when something travels towards us near the speed of light, along a direction close to our line of sight. This means the object travels almost as quickly towards us as the light it generates, giving the illusion that the jet's motion is more rapid than the speed of light. In the case of MAXI J1820+070, the southern jet is pointing towards us and the northern jet is pointing away from us, so the southern jet appears to be moving faster than the northern one. The actual velocity of the particles in both jets is greater than 80% of the speed of light, which is, amazingly, about 500 million miles per hour.