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so most galaxies in the Universe tend to live near other galaxies  in clumps called groups or clusters.  Our own galaxy, the Milky Way, lives in  a rather insignificant cluster we call around 3 Mpc   (Megaparsecs; one parsec = 3.26 light years $= 3.1 \times 10^{16}$ m) in diameter called  the Local Group. This cluster has two three  big galaxies, galaxies:  our own and own,  the Andromeda Galaxy (M31), in  orbit and the   Triangulum galaxy (M33); as well as  around each other. 50 smaller satellite and dwarf galaxies.  Each of these two the  big galaxies is a spiral galaxy, with a radius of about 10 kpc (kilo-parsecs; one parsec = 3.26  light years $= 3.1  \times10^{16}$ m).  We live about radii in the range 10-30 kpc.  Our solar system is around  8 kpc from the centre of our galaxy, so we are right out near the edge.   In addition a little over  halfway  to the two biggies,  there are two medium sized galaxies in our group, the Magellanic  clouds, and another 10 or so dwarf galaxies, all in orbit around each  other. The radius of our local group is about 1 Mpc (Mega-parsec). edge.  When astronomers first started mapping the sky, looking for galaxies,  they discovered an enormous number of them in the constellation of Virgo.