On July 13, 1862, while a young experiment in democracy was being ripped asunder by its first Civil War, The Springfield Republican reported a strange and wondrous celestial sighting in the undivided sky, as bright as Polaris. Within days, Lewis Swift and Horace Parnell Tuttle independently observed the phenomenon and determined it to be a colossal comet within days. Comet Swift-Tuttle — the largest Solar System object to periodically pass near Earth — is now known to return every 133 years, dragging in its long wake a dazzling annual gift: Each summer, as our lonely planet crosses the orbit of Swift-Tuttle and the debris shed by the icy colossus burn up in our atmosphere, the Perseid meteor shower streaks across the familiar sky, washing the whole of humanity with wonder.
For millennia, the Perseids have lit up the summer sky in an annual celestial spectacle — one of the most staggering on Earth, with as many as 200 vibrant meteors per hour — that just befell the awestruck human animal without a known cause or cosmic correlation. Some thought the streaks of light were debris from volcanic eruptions in faraway lands falling back to Earth. Others, including most scientists well into the nineteenth century, believed they were atmospheric phenomena like rainbows and lightning. Their cometic origins were unknown, and comets themselves were a mystery. For astronomers — even for Caroline Herschel, who became the world’s first professional female astronomer thanks to her prolific and perilous comet-hunting — they were little more than a diversion, a flexing of tenacity, a competitive game of discovery that advanced personal reputations rather than elemental truth. More than a century before Carl Sagan and Ann Druyan shed light on the still-unsolved science of comets, very little was understood about these mysterious visitors from outer space. The poetic science writer Emma Converse — the Carl Sagan of her epoch — prophesied that someday, “with a powerful grasp, like that of Newton, some watcher of the stars shall seize the secret of cometic history.”
That day began dawning in the small hours of November 13, 1833. Neighbors awoke neighbors with shouts of excitement as people gathered in the street to watch a rain of fire from beneath the invisible umbrella of the night. Shooting stars blazed across the dark sky at the breath-stilling rate of thousands, tens of thousands per minute. All of this was puzzling: It was November, not August; the meteors were falling at manifold the rate of the annual summer Perseids; and, at so high a density, they seemed to be streaming from a single source far from Earth, challenging the accepted notion that meteors were atmospheric phenomena.
