Submitted via IRC for TheMightyBuzzard
While focussing on the remains of an exploded star roughly 10,000 light-years away, a team of Japanese astronomers have stumbled across a mysterious cloud of molecules tearing through the Milky Way. So quickly, in fact, they've nick-named [...] the unknown phenomenon the 'Bullet'.
The cause of this cloud's ridiculous speed isn't clear, but so far all signs suggest it's been sent hurtling through space thanks to a rogue black hole.
On account of their light-sucking talent, black holes aren't known for being all that easy to spot. They sometimes reveal themselves by stealing material from a nearby star, heating it up and forcing it to emit X-rays.
If they're wandering alone in interstellar space, however, they tend to remain hidden.
Yet in this case, the shadowy influence of a black hole could explain why a cloud of molecules 2 light-years in size was moving forward at 120 kilometres per second (75 miles per second), and expanding at 50 kilometres per second (31 miles per second).
Weirder still, it was moving against the direction of the Milky Way's spin.
Source: http://www.sciencealert.com/astronomers-find-hints-of-a-black-hole-powered-supersonic-space-cloud
(Score: 3, Informative) by maxwell demon on Wednesday February 08 2017, @08:39AM
In the milky way: Somewhere between 100 m/s and 100 km/s, depending on where you are. [stackexchange.com]
Assuming it doesn't move through hot ionized medium, 120 km/s is very clearly above the speed of sound. However being a molecular cloud itself, it almost certainly doesn't move through a molecular cloud, which is at the lower range of sound speeds. Assuming the cloud moves through a warm medium, the cloud's Mach speed is at the order of Mach 10.
The Tao of math: The numbers you can count are not the real numbers.