Articles and information regarding individual Galaxies. A galaxy is a system of stars, dust, and gas held together by gravity. Our solar system is in a galaxy called the Milky Way. Scientists estimate that there are more than 100 billion galaxies scattered throughout the visible universe. Astronomers have photographed millions of them through telescopes. The most distant galaxies ever photographed are as far as 10 billion to 13 billion light-years away. A light-year is the distance that light travels in a vacuum in a year -- about 5.88 trillion miles (9.46 trillion kilometers). Galaxies range in diameter from a few thousand to a half-million light-years. Small galaxies have fewer than a billion stars. Large galaxies have more than a trillion.  ^[1]  Image: "NGC 4565: Galaxy on the Edge."