Donald Olson, an astrophysicist at Texas State University has a habit of taking well-known historical facts and turning them upsidown. Using the stars and Moon and a little bit of math, he's re-dated the original running of Marathon in 491-490 BC, precisely determined the spot in which Edvard Munch painted "The Scream," and figured out the exact minute that Vincent Van Gogh depicted in his painting "Moonrise." As if that weren't enough, now he's changing the date Julius Caesar landed in England, an event that sparked a massive battle and changed the course of Western civilization.
Olson and his colleague Russell Doescher have made a name for themselves pioneering a field they call 'astroforensics.' Poring over historical texts (in this case Caesar's Commentary on the Gallic War), the two piece together bits of astronomical information that were recorded around the time of the event in question - phase of the Moon is a common one, as are the locations of Venus and the Sun, often recorded in paintings. In Shakespeare's "Hamlet" a 'bright star' is mentioned, and that was enough to get Olson thinking that it wasn't a star at all, but a Supernova that lit up the skies in 1572.
Knowing the phase of the Moon, Olson could calculate exact dates when, say, the tides would've been right in 55 BC for Caesar to make his landing near Dover. As it turns out, those same lunar and tidal conditions only present themselves once every few hundred years or so, and August 2007 was one of those dates. So Olson and company went to Dover, chartered a boat, and floated through the English channel, just as Caesar had done. Riding the same currents as the Romans, Olson showed that the evening of Caesar's arrival must have been August 22-23 in the year 55 AD rather than August 26-27, as generations of scholars before him had thought.
Caesar's landing was under duress - thousands of Celtic tribesmen greeted him with arrows and spears. But the Romans prevailed, and began an invasion that would lead to the formation of England.
Not all of Olson's work has as much historical import - he also likes following in the footsteps of Ansel Adams, and predicting when the waterfalls in Yosemite National Park will be moonlit as just the right angle so that their spray produces a rainbow - and he's calculated every time that will happen for the next two years. But CSI's got nothing on this guy, who needs nothing but the night sky to solve his cases.
Source: Sky & Telescope