Archaeologist Uses 2,000-Year-Old Sky to Study Roman Ruins

If archaeology was once about digging through dirt, it is increasingly—like almost every other profession—about programming computers. Bernie Frischer, an Indiana University "archaeo-informaticist," has came up with a new theory about two Roman monuments. His finding are based on 3D reconstructions of the monuments using video game technology and calculations of the sun's position 2,000 years ago.

Archaeologist Uses 2,000-Year-Old Sky to Study Roman RuinsS

Frischer's work is made possible in part by ephemerides, or tables that give the position of celestial bodies at different points in time. Ephemerides were once actual tables written on paper, but now they're software programs, like NASA's Horizons system that can generate the position of an object in the sky at any time in history.

Archaeologist Uses 2,000-Year-Old Sky to Study Roman RuinsS

Example of ephemerides, via Wikimedia Commons

For Frischer, the time of interest is 2,000 years ago, when Rome's Ara Pacis, "Altar of Peace." was dedicated to then-emperor Augustus. The Ara Pacis sits in front of the 71-foot high Obelisk of Montecitorio. Archaeologists had long believed that the two monuments were so positioned that the shadow of the Obelisk would point directly at Ara Pacis on September 23, Augustus's birthday.

After creating 3D models of the two monuments using the game engine Unity and studying the sun's position, however, Frischer and his team believe the real date of interest is October 9. On this day, the sun would would pass directly over the top of the obelisk. He explains in an Indiana University press release:

"Inscriptions on the obelisk show that Augustus explicitly dedicated the obelisk to his favorite deity, Apollo, the Sun god," Frischer said. "And the most lavish new temple Augustus built, the Temple of Palatine Apollo, was dedicated to his patron god and built right next to Augustus' own home.

"So the new date of the alignment, Oct. 9, is actually what we know to be the annual birthday festival of the Temple of Palatine Apollo," he said. "No other date on the Roman religious calendar would have been as appropriate as this."

It's old-school historical research combined with 3D video game design and computer programming—archaeology for the 21st century.

Image via video from Indiana University