The Canis Majoris Dwarf Galaxy is the closest galaxy to our location in the Milky Way. At only 25,000 light-years away from the Solar System, it is even slightly closer to us than the core of our own galaxy. The Canis Majoris Dwarf Galaxy is about 42,000 light-years from the Milky Way’s Galactic Core. It is the latest in a series of newly discovered small galaxies found closer and closer to the Earth, the most recent being the Sagittarius Dwarf Elliptical Galaxy.
The Canis Majoris Dwarf Galaxy was discovered relatively recently, in 2003, by a team of astronomers from France, Italy, the UK, and Australia, using data derived via the Two-Micron All Sky Survey. The galaxy would have been discovered much sooner, but is located behind the galactic disc from our viewpoint, which is filled with opaque dust, and the galaxy itself is relatively small, with “only” a hundred million or so stars.
The Canis Majoris Dwarf Galaxy is an irregular-shaped galaxy, as it is currently in the process of being ripped apart by the gravitational force of the Milky Way Galaxy. In fact, before the galaxy itself was discovered, astronomers conducting the Sloan Digital Sky Survey found a wispy ring of stars circling the Milky Way, which was dubbed the Monoceros Ring. The Monoceros Ring is an example of a stellar stream, formed by tidal forces. It wraps around the Milky Way Galaxy a total of three times.
Hundreds of millions of years ago, the Canis Majoris Dwarf Galaxy was likely considerably larger than it is today, and some astronomers figure that it may have contributed as much as 1% of the Milky Way’s current stellar material. As our galaxy devours the Canis Majoris Dwarf through of gravity, eventually all of its stars will be integrated into the Milky Way, becoming all but indistinguishable from the primary mass.