NASA's Hubble Space Telescope records a giant cloud of fiery gas taking a trajectory path as it goes back to the Earth's galaxy at a staggering speed of 700,000 mph.
Normally, hundreds of high-velocity clouds pass through the borders of the galaxy. They move at constant speed and paths so they are kept out of the galactic plane. However, the fiery gas, dubbed the Smith Cloud, is considered unique since its route is well-studied. A doctoral astronomy student, Gail Smith, discovered the Smith Cloud in the '60s.
It is much more distant and moves towards the Milky Way at an incredibly rapid speed. Astronomers suggest that this cloud was hurled from the external areas of the galactic plane by about 70 million years ago. Data shows that the giant cloud is likely to collide with the galaxy's disk in 30 million years, a long time for humans but a very short time for the galaxy.
"Our galaxy is recycling its gas through clouds, the Smith Cloud being one example, and will form stars in different places than before. Hubble's measurements of the Smith Cloud are helping us to visualize how active the disks of galaxies are," Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland, said.
Since its discovery, astronomers have assumed that the cloud may be a starless galaxy. For the first time, thanks to the Hubble Space Telescope, they were able to observe and determine the amount of heavier elements relative to helium and hydrogen.
They also identified sulfur in the cloud, which is known to absorb ultraviolet light. As expected, they found that the cloud is copious in sulfur, which means it was supplemented by compounds from stars. This somehow sheds light on the mystery of the Smith Cloud and its origin.
Many other issues, however, arise. It is yet to be explained how it reached where it is today and what event happened that propelled it from the Milky Way's galactic disk. Future research will further elaborate on the Smith Cloud as to where it came from.
