Nibiru or Planet X is not likely to come into our solar system in May or anytime at all, said Mike Heiser, an expert on ancient texts, who appeared on Monday night's show. Heiser has studied the same Sumerian texts and cuneiform that Zecharia Sitchin has based his "12th Planet" theories on and come to very different conclusions.

He believes that the texts indicate that Nibiru was a star rather than a planet. "Nibiru shows up in an annual catalogue of star movements," which doesn't correlate with Sitchin's 3,600 year orbit for the planet, Heiser explained. The Sumerians referred to Nibiru as the planet or star of "crossing." To Heiser this indicates they were talking about the Polar Star, which changes over time based on the gradual wobbling or "precession" of the Earth.

Heiser said the Sumerian references to the Anunnaki do not point to an extraterrestrial presence. The texts "just don't support Sitchin's reconstruction," he stated. Further, his decoding of Sitchin's oft-cited cylinder seal yields a star and a constellation rather than the sun and 11 planets.