This discovery could help explain how so-called high velocity clouds (HVCs) remain mostly intact during their mergers with the disks of galaxies, where they would provide fresh fuel for a new generation of stars.
Currently, the Smith Cloud is hurtling toward the Milky Way at more than 150 miles per second and is predicted to impact in approximately 30 million years.
When it does, astronomers believe, it will set off a spectacular burst of star formation. But first, it has to survive careening through the halo, or atmosphere, of hot ionized gas surrounding the Milky Way.
Lead author Alex Hill, an astronomer at Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO), said that 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.
Earlier research had indicated that the Smith Cloud has already survived punching through the disk of our Galaxy once and -- at about 8,000 light-years from the disk -- is just beginning its re-entry now.
When the Smith Cloud eventually merges with the Milky Way, it could produce a bright ring of stars similar to the one relatively close to our Sun known as Gould's Belt.
The study has been published in the Astrophysical Journal.
--ANI (Posted on 02-11-2013)