A black hole is blasting winds at 20% the speed of light
https://www.esa.int/Science_Exploration/Space_Science/XMM-Newton/Flaring_black_hole_whips_up_ultra-fast_winds?utm_source=join1440&utm_medium=email&utm_placement=newsletter&user_id=6934b7a4fb48023c5a0bc6f1
2 Comments
The actual title is
> Flaring black hole whips up ultra-fast winds
The point of the article is that these winds, which are a normal velocity for a black hole jet, appeared within a day of an xray flare.
Astronomer here! I’ve gotta say, 20% isn’t THAT high for a black hole- I study outflows from black holes that recently shredded stars, and while this is on the higher end for the majority of the “normal” population, where we see outflows at 10-20% the speed of light all the time. The way to think about this is it sounds like a lot, but this is actually roughly similar to what we see from a supernova explosion in terms of speed and energy.
(For those who are wondering what is an abnormal end of this population, maybe 1% of black holes that have winds and outflows also launch a [relativistic jet](https://nustar.caltech.edu/page/relativistic-jets), ie material going at nearly the speed of light. Lots of unanswered question there!)
What’s interesting to me IMO about this find is the fact that there is an X-ray flare associated with this particular wind ejection, which is a first (otherwise the data from this study is in ultraviolet). The reason X-ray is important is different kinds of physical processes emit in different parts of the electromagnetic spectrum, and X-ray traces some of the highest energy material present. Which allows us to pinpoint the velocities present in this particular outflow, for example, and how it changes over time! But that’s a bit more of a subtle argument for the public, so I could understand why the press release would go for an “omg 20% the speed of light!” headline even when that’s maybe not the most exciting thing going on here to a scientist. 🙂