Hierarchy of the Universe

• Our Sun is just one (rather boring) star in our Galaxy (out of about 100 billion)

• Our galaxy is part of the Local Group that includes M31 (Andromeda)

• The galaxies in our group are all gravitationally bound to each other

• None of the galaxies are moving fast enough to escape the group

• Some of the galaxies in the group are moving towards us (like M31) - blueshifted