In an earlier post, I looked at the possibility that the paintings of Vincent Van Gogh might include a very physical archive of 19th-century meteorological events, with sand, dust, pollen, and other airborne particulates from the days Van Gogh painted en plein air now trapped for all art history inside the vibrant swirls of his canvases.
Adam, from Design Under Sky, then left a comment saying that this unintentional archive of sand already exists, with or without such speculation: "Sand was used as an ink blotting material and remnants are often still found in manuscripts today." Every library is thus also a museum of sand.
But I completely failed to mention an article that has fascinated me for more than a year now; I believe I originally found it via Andrew Ray of Some landscapes.
In a feature for COSMOS Magazine called "Sky detectives," we read that "forensic astronomers... are seeking clues to historical events embedded in artworks and literature." 
In other words, similar to the idea of geomythology—in which ancient tales of floods or vengeful fire gods can be re-interpreted in light of newly found evidence for catastrophic tsunamis or volcanic eruptions—"forensic astronomers" look for more celestial clues. Things like Halley's Comet burning through the night sky of the Bayeux Tapestry will catch their eye, or supernovas as depicted in Native American rock art.
These details, hidden in plain sight, can be used to indirectly piece together long-gone astronomical events.
The following very long quotation gives at least some idea of how extraordinary the results can be; it's like something out of Minority Report:
- Donald Olson, a physics professor at Texas State University in San Marcos, U.S., has used similar techniques to help art historians pin down details of famous paintings. In 2000, for example, he found the location at which Vincent van Gogh created one of his last paintings, The White House at Night.
Knowing that van Gogh painted it in mid-June, and the direction in which the house faced, Olson was able to determine that a bright star in the painting was mostly likely the planet Venus, which would have been prominent at the time.
Two years later, Olson used a similar process with another van Gogh painting, Moonrise. That painting depicts the full moon rising behind an overhanging cliff in southern France. Historians knew the work was made sometime in 1889, and haystacks in the foreground indicate that the time of year is somewhere around harvest season.
Olson's team hunted down the location and, with a bit of astronomical detective work, determined that there was only one date on which the Moon rose in the right place: 13 July 1889. Since van Gogh once said he never worked from memory and always painted what he saw, this was probably the date on which he started painting Moonrise.
Every time I see that scene I wonder what the flash was, and, more importantly, where it went: if something later crashed down into the sands of North Africa, or hit a cliff in Arizona, or splashed into the ocean waters much further out at sea. Or simply burnt up into dust and fiery particles.
[Image: Rock art possibly depicting a supernova. Photo by John Barentine, Apache Point Observatory, courtesy of SPACE.com].But what if someday you find a meteorite and you somehow piece together evidence for when it fell to earth—and you find that it was during the summer that Steven Spielberg filmed Jaws. You find out exactly where they filmed Jaws, and you keep digging deeper, and then, finally, there it is: some fantastic piece of irrefutable evidence that proves you have just discovered the very object that once flew through the sky in a film seen by countless millions of people around the world. Jaws, after all, is the seventh-highest grossing film of all time.
It's archaeo-astronomy via Hollywood film history.
In any case, as you will see in the "Sky detectives" article, our forensic astronomers begin reading nothing less than The Odyssey, looking for astronomical clues ("...the poem describes Odysseus steering his boat by the positions of the constellations Boötes and the Pleiades [which] establishes the date as early spring...").
But as they start putting Homer's descriptions of the constellations, and the precise order and time of year in which Odysseus saw those constellations, into their weird software that maps the movement of the earth and our nearby planets through 49,000 years of history... my hair began standing on end.
All these astronomical clues—in ancient poetry, famous paintings, and the overlooked skies of film history—simply waiting to be deciphered.
