A black hole is stirring gas across 300,000 light-years
I read about this yesterday and I still keep thinking about how big it is.
There is a quasar called H1821+643, over in the constellation Draco, about 3.4 billion light-years away. A quasar is a supermassive black hole eating gas so fast that the whole thing outshines a galaxy. We have known about this one for a while, so it is not a new object.
The new part is that Japan's XRISM X-ray satellite took a careful look at it. XRISM measures X-ray light precisely enough to tell how fast gas is moving. It does that by watching the emission lines from iron ions shift and smear. A team led by Yamada, with people from Kanazawa University and Tokyo Metropolitan University, used that to measure the turbulence in the hot gas around the quasar.
The number came out about 100 times higher than the models predicted. The churning gas covers roughly 300,000 light-years, which is well past the edge of the black hole's own galaxy. The write-ups say the energy involved is comparable to several billion supernovae. The paper is in Nature Astronomy.
The bit I keep coming back to is that this is one object, and its wind reaches across a region bigger than the galaxy it sits in. Astronomers already thought black holes push gas around and shut down star formation in the process. This says the effect is a lot stronger than anyone had it in the models.
I also like that the instrument doing the work here is basically a very good thermometer for X-rays. I did not expect that to be the thing that made the measurement possible.
Source: https://www.sciencedaily.com/releases/2026/09/260914102429.htm