Comets have always been afforded a special place in the minds of human beings. In fact, from the earliest days of recorded history up through the 17th century, most people thought they were harbingers of doom or portents or some incredibly important events – perhaps good but usually bad. Thought to be specters from beyond, ghosts sent from heaven or hell and carrying wickedness or good, comets spent the entire history of human culture being misunderstood until just the last 300 years. And the real understanding of comets, as we’ve seen, has only developed over the past century. It’s difficult to blame the ancients for singling out comets, as so few things in the sky seem to change over short time intervals. To most, the sky, filled with stars, seems essentially static. Even the motions of the planets, the Moon, and the Sun are comfortable. But comets were outside the realm of the comfortable, and their uninvited, sudden appearances would shake the foundations of belief.

The Roman philosopher Lucius Annaeus Seneca, aka Seneca the Younger (ca. 4 b.c.–a.d. 65), summarized the early take on comets – as opposed to the always-visible parts of the heavens, the Sun, Moon, and so on – in one of his writings. “No man is so utterly dull and obtuse,” he penned,