The Discovery

On December 10, 2010, an amateur Russian astronomer named Leonid Elenin discovered a long-period comet in the U.S. state of New Mexico. The near-earth object was given the name of Elenin and was estimated to be 3-4 km in diameter. Almost immediately after the discovery was announced, articles began to appear on the Internet that claimed the comet was dangerous to Earth. People began to make connections between Elenin and extinction level events.

It was originally estimated that the comet would pass within .24 Au (Astronomical Units) of the Earth, which is pretty close. The distance is closer than the Hale-Bopp Comet of 1997, which gained more media attention. The story reached a larger audience after it was disclosed that while using the JPL Horizons system with an observed orbital arc of 235 days, the comet shows an orbital period of approximately 11,800 years. In the history of Earth, 12,000 years ago was a sensitive time and the bridge between the Pleistocene and Holocene geological epochs.