If Andromeda Were Brighter, This is What You'd See
Andromeda is the closest large galaxy to us. At 140,000 light years across, it’s 40% bigger than our 100,000 light year diameter Milky Way. Andromeda is 2.5 million light years away from us, or about 25 Milky Way diameters. Light takes 2.5 million years to pass between the two galaxies, so if a fancy Andromeda alien is viewing us with a telescope right now, it’s seeing a bunch of Australopithecus walking around being unappealing.