Neither its nature nor origin have been totally explained.
Those words were written by a team of astronomers from Keio University in Japan to describe a strange, super fast cloud of molecules currently speeding through the Milky Way against the direction of the spin of our galaxy. The cloud measures over two light-years in size and is hurtling through the galaxy at speeds never observed in similar clouds of space dust. The cloud, nicknamed “the Bullet,” is traveling at speeds approaching 75 miles per second (120 km/s). The cloud is also stretching as it flies through space, expanding at nearly 31 miles per second (50 km/s). Yikes.
The cloud was spotted using telescopes at the Nobeyama Radio Observatory in Chile. Astronomers currently can’t explain the staggering speed of the cloud but have proposed two possible scenarios which both involve black holes. In the first scenario, an explosion caused by a massive supernova could have pushed a cloud of interstellar gasses and dust through a relatively small black hole. The gravitational force of that black hole could have acted like an engine, accelerating the portions of the cloud which managed to escape its event horizon.
Masaya Yamada, a graduate student at Keio University, states however that the speed of the strange cloud doesn’t quite fit with the models generated from data gathered from the remnants of the nearest known supernova, called W44:
Its kinetic energy is a few tens of times larger than that injected by the W44 supernova. It seems impossible to generate such an energetic cloud under ordinary environments.
The next possible scenario involves a small, super-dense black hole zooming through space. Were such a black hole to punch its way through a cloud of matter in space, it might be able to generate the type of directional velocity seen in the Bullet.
Black holes have been previously observed to hurtle through space, and astronomers detected a similar - although slower - exhaust plume shooting out of a black hole last year. Whichever scenario is eventually confirmed, the Bullet will likely demonstrate that there are many more black holes lurking in the vast blackness of space than we currently realize.