Unusual Spiral Galaxy M66
Why isn't spiral galaxy M66 symmetric? Usually density waves of gas, dust, and newly formed stars circle a spiral galaxy 's center and create a nearly symmetric galaxy . The differences between M66 's spiral arms and the apparent displacement of its nucleus are all likely caused by the tidal gravitational pull of nearby galaxy neighbor M65 . Spiral galaxy M66, pictured above , spans about 100,000 light years , lies about 35 million light years distant, and is the largest galaxy in a group including M65 and NGC 3628 known as the Leo Triplet . Like many spiral galaxies, the long and intricate dust lanes of M66 are seen intertwined with the bright stars and nebulas that light up the spiral arms.