Galaxies come in three main types: spiral galaxies like our Milky Way, elliptical galaxies which are mainly the end result of two or more merged galaxies and irregular galaxies, which are all the other galaxies with unusual and irregular shapes. Galaxies contain between 10 million stars - these galaxies are called dwarf galaxies - and more than hundred trillion stars. There are more than 170 billion galaxies just in the observable universe (which is only a part of the whole universe).

The closest galaxies to the Milky Way are the Small Magellanic Cloud (a dwarf galaxy) and the Large Magellanic Cloud (an irregular galaxy). They are 150 000 to 200 000 light years distant. Only Canis Major Dwarf is still closer – 25000 light years - but it will soon be part of the Milky Way since it is being cannibalised by the Milky Way right now. The stars with all their planets will survive and then be part of the Milky Way, so maybe the word cannibalised is a bit exaggerated.