The moon and the monster: astronomers shed light on Frankenstein
Astronomers have established moonlight would have played on the shutters of Frankenstein author Mary Shelley's bedroom on the night she always said it did - the night she thought up the plot of her famous novel.
Astronomers in Texas have used the light of the moon to highlight the hour of creation for Victor Frankenstein and his notorious monster - and defend the memory of their teenage creator, Mary Shelley.
The inspiration came in a waking dream between 2am and 3am on the morning of 16 June 16, 1816, they explain in the November issue of Sky and Telescope.
In the preface to the third edition of Frankenstein Shelley described a villa party: Lord Byron, Percy Shelley, herself and Byron's physician Polidori, and the famous challenge by Byron that each of them should begin a ghost story. She also described her repeated inability to come up with an idea until a moment of inspiration during a sleepless night in her dark room, behind closed shutters "with the moonlight struggling to get through".
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And then, she continued: "I saw with shut eyes, but acute mental vision ... I saw the hideous phantasm of a man stretched out, and then, on the working of some powerful engine, show signs of life ..."
The two poets soon lost interest. Polidori kept a diary of his days with Byron and some enigmatic entries have prompted scholars to suggest that to enhance sales Mary Shelley might have composed yet another fiction about the chronology of literary creation. Did Byron make his challenge on 16 June? Was Mary Shelley writing the next day?
Or did she spend several days agonising and think of her tale on 22 June?
"Our calculations show that can't be right, because there wouldn't be any moonlight," says Donald Olson, from Texas State University in San Marcos. Just as astronomers can predict lunar cycles decades ahead, they can say when they happened centuries in the past.
In August 2010, Professor Olson, two colleagues and two students went to Lake Geneva to discover when moonlight would have hit the windows, and penetrated the shutters, of Mary Shelley's bedroom.
Shelley reports that she stayed up beyond the "witching hour" of midnight. By June 22, the moon would then have been a waning crescent, masked by a hillside.
But a bright, gibbous moon would have cleared the hillside to shine into Mary Shelley's bedroom window just before 2am on June 16.
So Shelley's version of events is supported by evidence.
Byron probably made his challenge somewhere between June 10 and 13, 1816. On June 15, according to both Polidori and Mary Shelley, the party talked about the "principle" of life. The monster and the tormented scientist were dreamed up in the small hours of that night.