Chaucer, for those with only a passing familiarity with the author, was a rather accomplished amateur astronomer in his day, having written an entire treatise on the astrolabe, commonly used to calculate the positions of stars and planets. So it's not surprising that The Canterbury Tales, his greatest work, is littered with references to the night sky.
Olson analyzed one line in particular: "And by his magic for a week or more/It seemed the rocks were gone; he'd cleared the shore." Using computer simulations, Olson concluded that the scene described by the poet occurred in 1340, when the sun and moon were closest to the Earth and their combined gravity (plus a solar eclipse for good measure) made for very high tides off the Brittany coast.
From that point on, he had the bug for what he calls "forensic astronomy." He has analyzed the photographs of Ansel Adams, for example, and the paintings of van Gogh and Edvard Munch.
For instance, in 1995 he concluded that Munch's best-known painting, The Scream, must have been inspired by an actual blood-red sky the artist witnessed in Oslo in 1893, a result of the earlier eruption of Mount Krakatoa, which spewed gas and ash into the atmosphere, making for some pretty spectacular sunsets.
Olson's analyses have also shed light on historical mysteries. He helped clear up confusion as to Julius Caesar's actual landing site when the Roman general invaded Britain in 55 BC. Olson concluded that the date given in Caesar's history was incorrect: the landing (near the town of Deal, just northeast of the Dover cliffs) happened on August 22 or 23, not August 26th.
And now he has turned his keen astronomer's eye to Mary Shelley's inspiration for Frankenstein.
The story is practically legend. In the summer of 1816 - an especially cold and rainy season thanks to the eruption of Mount Tambora the year before - Shelley (then 18), her future husband Percy, and fellow writer John Polidari, visited Lord Byron at the Villa Diodati in Lake Geneva Switzerland.
The weather kept the group indoors much of the time, chatting about writing, yes, but also experiments involving "galvanism" - applying electrical current to dead creatures - and the possibility of bringing a corpse back to life. Oh, and they also read a few German ghost stories aloud, which gave Byron an idea: "Hey! Why don't we all go off and write our own supernatural story?"
Here's where the controversy starts. Most history books report that, around the "witching hour" (midnight), Byron made the suggestion on June 16, and she began writing the following day. But according to Mary Shelley herself, inspiration didn't strike right away; she recalled a few days passing before her "waking dream." As she described it in her Preface:
I saw the pale student of unhallowed arts kneeling beside the thing he had put together. I saw the hideous phantasm of a man stretched out, and then, on the working of some powerful engine, show signs of life, and stir with an uneasy half vital motion.
Other accounts still have Byron making the suggestion on June 16, with Shelley being inspired to write days later on June 22. The problem, says Olson, is that "our calculations show that can't be right, because there wouldn't be any moonlight on the night she says the moon was shining." It's also contradicted by a June 18 passage in Polidari's diary, where he tells of the gathering, and of Byron's challenge and lamented, "the ghost-stories are begun by all but me."
So, did Mary Shelley embellish her account, the better to market the second edition of her book? She wouldn't be the first author to do so - or the first person to recollect a manufactured memory and yet be firmly convinced it happened just that way. But Olson insists that her memory was just fine - she started writing on June 17, and there was indeed a bright moon the night before.
To prove it, Olson and his team went to the Villa Diodati on Lake Geneva and made a lot of measurements, then consulted weather records from June 1816. They found that a "bright, gibbous moon would have cleared the hillside to shine into Shelley's bedroom window just before 1 a.m. on June 16."
As for Shelley's contention that several days passed between the challenge and her being inspired to write, Olson points out, "There is no explicit mention of a date for the ghost story suggestion in any of the primary stories - the letters, the documents, the diaries, things like that. Nobody knows that date, despite the assumption that it happened on the 16th." Not even Polidari's diary. But those documents do narrow the range of dates to between June 10 and June 16. So several days could have elapsed between the challenge and Shelley's "waking dream."
So don't be calling Mary Shelley forgetful, or an outright liar, literary critics! The only whopper she told was the one about the mad scientist who created a monster - a fabrication fit for the ages.
Top photo: Villa Diodati and the Moon reflecting in Lake Geneva appear in this hand-colored engraving circa 1835, from the collection of Donald Olson. Center photo: A scene from Mel Brooks' Young Frankenstein. Bottom photo: A page from Mary Shelley's draft manuscript of Frankenstein, Wikimedia Commons.