Your humble moderator will grant you that it’ll take a significant amount of time, but the results of this one ought to be spectacular.

Science now reports:

It’s large, it’s fast, and it’s heading toward the Milky Way. Less than 40 million years from now, a giant cloud of hydrogen gas, clocked at 250 kilometers per second, will smash into our home galaxy, likely setting off a huge burst of star formation. In fact, the cloud contains enough gas to form a million stars like our sun, astronomers reported here today at the 211th meeting of the American Astronomical Society. The finding also indicates that pristine material is still entering the relatively mature Milky Way.

Many clouds of hydrogen surround the Milky Way. But astronomers didn’t start spotting them until a half-century ago–after the advent of radio telescopes, which are able to detect cold, neutral hydrogen gas. The early observations were not accurate enough to determine the clouds’ distances, masses, or directions of motion, however.

Now, thanks to more powerful telescopes such as the 100-meter Robert C. Byrd Green Bank Telescope in Green Bank, West Virginia, these clouds are finally getting their close-up. The first to be spotlighted in extreme detail is Smith’s Cloud, named after Dutch astronomy student Gail Smith, who discovered it in 1963. Curious about the cloud’s elongated shape, a team of astronomers led by Felix “Jay” Lockman of the National Radio Astronomy Observatory in Charlottesville, Virginia, took tens of thousands of radio brightness measurements. The data reveal that the cloud is just 8000 light-years away from the Milky Way’s central plane, making it the closest one known. Its cometary shape is apparently due to the tidal effects of the Milky Way.

According to this astronomy article, there should be some spectacuar fireworks when this gas cloud gets incorporated into the Milky Way, creating tens of thousand of massive clouds millions of years into the future. It’s going to be some kind of light show.