Mass of Hydrogen Gas Headed for Milky Way May Have Nothing to Fear

A gigantic mass of hydrogen gas headed straight for the Milky Way may not have anything to fear after all, a new study found.

According to researchers, the Smith Cloud may survive the collision scheduled to take place in roughly 30 million years thanks to a magnetic field located deep inside it.

If true, the finding may help explain why so many clouds like the Smith Cloud are able to come out of their mergers with galaxies' disks mostly in tact.

"The million-degree upper atmosphere of the Galaxy ought to destroy these hydrogen clouds before they ever reach the disk, where most stars are formed," said Alex Hill, an astronomer at Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) and lead author of a paper published in the Astrophysical Journal. "New observations reveal one of these clouds in the process of being shredded, but a protective magnetic field shields the cloud and may help it survive its plunge."

A fair amount of mystery still surrounds the Smith Cloud, with researchers still unsure as to its origins.

"The field we observe now is too large to have existed in its current state when the cloud was formed," Hill said. "The field was probably magnified by the cloud's motion through the halo."

Previous studies suggest this isn't the first time the Smith Cloud has collided with the Milky Way and is already beginning its prolonged re-entry.

"The Smith Cloud is unique among high-velocity clouds because it is so clearly interacting with and merging with the Milky Way," said Felix J. Lockman, an astronomer at the National Radio Astronomy Observatory. "Its comet-like appearance indicates it's already feeling the Milky Way's influence."

When the cloud finally does merge with the Milky Way, it's possible that it will create a ring of stars like Gould's Belt, located fairly close to the Sun.

"Our Galaxy is in an incredibly dynamic environment," Hill said, "and how it interacts with that environment determines whether stars like the Sun will continue to form."