What is the closest galaxy to the Milky Way?
The closest known galaxy is often said to be the Canis Major Dwarf Galaxy, about 25,000 light-years from the Sun. The nearest large galaxy is Andromeda, 2.5 million light-years away.
The Milky Way is surrounded by dozens of small satellite galaxies. The Canis Major Dwarf, announced in 2003, appears to be a stream of stars being torn apart by our galaxy's gravity, and some astronomers argue it may not be a separate galaxy at all. If it is not counted, the Sagittarius Dwarf Galaxy, about 70,000 light-years away, takes the title.
The best-known neighbors are the Large and Small Magellanic Clouds, about 160,000 and 200,000 light-years away. They are easy to see with the naked eye from the Southern Hemisphere, looking like detached patches of the Milky Way. They are named after the explorer Ferdinand Magellan, whose crew described them during his voyage.
Our big neighbor
The Andromeda Galaxy is the nearest large spiral galaxy and the biggest member of our Local Group, a cluster of more than 50 galaxies. It contains roughly a trillion stars. When you look at Andromeda, you see light that left it about 2.5 million years ago, long before modern humans existed.
Did You Know?
Andromeda is the most distant object most people can see with the naked eye, although you need a dark sky away from city lights to spot it.