Too much information in the Odyssey

Eventually, the stars took a luckier turn for the embattled hero of the Odyssey — while for his enemies, the noontime sun turned ominously dark.

Homer marked Odysseus’ last days of wandering on his way back to his kingdom of Ithaca with accurate references to the position of the stars and planets and to a solar eclipse, researchers propose in an upcoming Proceedings of the National Academy of Sciences.

But the findings, if true, would open a major puzzle. Scholars believe that the poet lived some time after 800 B.C., and that the Greek astronomy of his time was not sophisticated enough to calculate where the planets had been at the time of the Trojan war, which took place up to four centuries before. “It would require a major revision of the history of ancient astronomy,” warns James Evans, a historian of astronomy at the University of Puget Sound in Tacoma, Wash.

At the story’s climax, 10 years have elapsed since the Trojan War, and since the veteran Odysseus never made it back, suitors besiege his wife Penelope, each of them hoping to make her his bride. But as the suitors gather for a banquet, the seer Theoclymenus says that the sun has suddenly disappeared, and foresees the suitors’ ghosts running away toward Hades. (Odysseus, who has secretly already returned, will soon lay death upon them.)

Despite the mythical nature of the story, some scholars proposed in the 1920s that the the description of this disappearance of the sun may have referred to a solar eclipse that actually took place in the Mediterranean around noon on April 16 1178 B.C.

Now Constantino Baikouzis, an astronomer at the La Plata Observatory in Argentina, and

Marcelo Magnasco, a mathematical physicist at Rockefeller University in New York City, say that all other references the poem makes to the positions of the stars and planets, taken together, point to the same conclusion. “Whoever wrote the poem may have been referring to astronomical events,” says Magnasco.

In chronicling the final month of Odysseus’ travels, Homer gives three explicit references. As Odysseus sets sail from Calypso’s island, Homer writes, he sees the constellations of Pleiades and Boötes; these are far apart from each other in the northern sky and so are rarely visible at the same time from Greece’s latitude, says Magnasco. Then, just five days before the banquet, Venus is visible just before dawn. And the banquet takes place during a new Moon, which is necessary for a solar eclipse to happen.

Baikouzis and Magnasco supplement these facts with another, admittedly controversial, reference to a trip by the god Hermes as representing the motion of the planet Mercury. Although the Roman god Mercury was associated with Hermes, the Greeks did not associate Hermes with the planet until four centuries after Homer’s time.

The authors used these four references to give an independent estimate of the date of the banquet. Astronomers know that these four events happen periodically, but with different periodicity. “The four of them rarely repeat in the same pattern, because they go out of sync with one another,” Magnasco says. And in April 1178 B.C, all four events happened in a sequence that matches precisely Homer’s day-to-day account of the month leading to the suitors’ banquet.

Trouble is, scholars believe that Homer — whose very historical existence is uncertain — probably lived in the eighth century B.C., and that he assembled the Odyssey from a vast oral tradition. Homer could have inherited historical knowledge about a total eclipse from the 12th century B.C. But it seems difficult to explain how he could have calculated the positions of the stars and planets in the days leading to it, since at his time, only the Babylonians had the ability to do that.

Evans says that Baikouzis and Magnasco seem to have done careful calculations. But he calls their thesis a “castle of cards,” since it relies on the uncertain association of Hermes and Mercury.

For Robert H. van Gent of Utrecht University in the Netherlands, “the biggest problem is how to explain the apparent coherence of the astronomical data, which Homer either found in a now-long-lost historical source, or was able to project by calculation some three or four centuries back in time.”

Other authors, including J.R.R. Tolkien and Dante, included precise astronomical references in their works, van Gent notes. “But they had easy access to astronomical tables or almanacs. In the case of Homer, one can only guess how he did it, and marvel at his ingenuity.”