Galaxies are large systems of stars and interstellar matter, typically containing several million to
some trillion stars. Some masses are between several million and several trillion times that of
our Sun. Some galaxies contain extensions of a few thousand to several hundred thousand light
years, typically separated by millions of light years. They come in a variety of flavors: Spiral,
lenticular, elliptical and irregular. Besides simple stars, they typically contain various types of star
clusters and nebulae.
We live in a giant spiral galaxy, the Milky Way Galaxy, that measures 100,000 light years in
diameter, and has a mass of roughly a trillion solar masses. The nearest dwarf galaxies, satellites
of the Milky Way, are only a few 100,000 light years distant, while the nearest giant neighbor, the
Andromeda Galaxy, also a spiral, is about 2-3 million light years distant.
M31 - Andromeda Galaxy
Earlier Galaxy Images