It strikes me as quietly ridiculous, sitting in Middlemarch with a telescope barely bigger than a coffee mug, peering 60 million light-years into the dark. But there I was last week, watching a gentle arc of galaxies sweep across Virgo, trailing through the sky like a wisp of smoke from some cosmic campfire. It is called Markarian’s Chain. The name belongs to the Armenian astronomer Benjamin Markarian, who in the 1960s used one of the great survey instruments of the Soviet era to map groups of galaxies that appeared physically connected rather than merely scattered by chance across the heavens. Markarian’s Chain belongs to the Virgo Cluster, a gathering of more than a thousand galaxies, all huddled together some 55 to 65 million light-years from here. Through the eyepiece, it shows up as a gentle curve of faint, glowing smudges. Each one is a galaxy, home to billions, perhaps even trillions of stars. Some are giant ellipticals. Others are spirals, their arms busy with newborn stars and streaks of darkness.…