Galaxies are sprawling systems of dust, gas and dark matter. They contain anywhere from a million to a trillion stars that are held together by gravity. Nearly all large galaxies are thought to contain supermassive black holes at their centres.
The deeper we look into the universe, the more galaxies we see. It is estimated that the observable universe contains two trillion (2,000,000,000,000) galaxies. Some are similar to our own Milky Way galaxy, while others are quite different.
All images were taken with the equipment shown in the equipment section.