Sagittarius Loses Two Streams of Stars to the Milky Way

After analyzing data from the Sloan Digital Sky Survey (SDSS-III), investigators determined that two massive streams of stars were recently (in astronomical terms) removed from the Sagittarius dwarf galaxy, and incorporated into our own Milky Way.

Astronomers have been proposing that such streams should become apparent in the case of galactic collisions, but thus far actual instances of such events have not been noticed. Now, the SDSS-III shows two such streams in our galaxy's southern hemisphere.

At one point, the dwarf galaxy was one of the brightest companions the Milky Way had, but massive tidal forces have since crushed and stretched it by a huge amount. In just a few millions of years, the object will be completely incorporated into the galaxy.

In the near future, experts hope to use the new data to gain a deeper understanding of how the Milky Way grew through galactic collisions over the past few billion years. It is known to have consumed at least 3 or 4 dwarf galaxies since it first began developing, some 9 to 10 billion years ago.