Loftwings and Demons

Blob of hot gas swirls around Milky Way black hole at 30% speed of light

I have a fascination with objects travelling at relativistic speeds, but it can be kind of difficult to find such motion relative to our own. Naturally I was fascinated to hear about an object travelling at 30% the speed of light, even if it was just an intermittent blob of gas that didn't even last 2 hours before being ripped apart again.  

Scientists don’t fully grasp what causes flares such as the one Chandra detected. One theory points to interactions between material in the black hole's accretion disk and the magnetic field surrounding the black hole. In the case of Sgr A*, the researchers think the magnetic field acts as a barrier, preventing the black hole from devouring as much material as it otherwise would. This magnetic blockage causes gas and dust to clump up in certain areas around the black hole. 

Eventually, this built-up tension causes one of the magnetic field lines to temporarily break, allowing the black hole to gorge itself. The breakage also releases energy into the surrounding material, forming a hot bubble of plasma. 

Initially, these hot spots might primarily emit X-rays, Wielgus told Astronomy. “Maybe it needs a bit of time to cool down to show up at low frequencies corresponding to millimeter [radio] wavelengths.” It was these latter wavelengths that ALMA was able to detect. 

On average, a hot spot typically lasts for a single orbit before being sheared apart by the black hole. In this case, the clump of gas was zipping around the Milky Way's black hole at some 30 percent the speed of light. At those mind-bending speeds, it was able to complete a lap in about 70 minutes, and it was torn apart some 35 minutes later. 

I also love learning more about black holes, and Sgr A* is the big one in the Milky Way, so I've been following the research on it.