http://spaceobs.org/en/tag/comet-elenin/ (great resource)
http://translate.google.com/translate?hl=fr&ie=UTF-8&sl=pl&... (orbit projected by nasa)
Bright Mag 6-8
Named after its discoverer, Leonid Elenin, it is a comet with a hyperbolic trajectory (an object along which will [it is assumed] coast to infinity) whose perihelion is projected at .44 au on sept 9th 2011. It currently has an eccentricity greater than one, making the predictability of its complete orbit difficult. With such a wide eliptical orbit being hyperbolic, there is a good possibility that once it passes through the solar system it will never return. It will also have a magnitude of 6-8 after passing the sun, however will be un-viewable for a period of time.
Its speculated by many people that this comet could “fulfill” the Nibiru Collision Prophecy, however the likely-hood of that is extremely low due to the constant changes in projector as the object gets closer. Another interesting aspect of that common thread involving C/2010 X1 is that the “prophecy” was made by Nancy Lieder, who claims to receive information from aliens located in the Zeta Reticuli star system through an implant in her brain. Her original prediction was timed in 2003 [proposed in 1995] but subsequently abandoned; it was adopted by other doomsday groups, however, and is most frequently associated with the 2012 apocalypse phenomenon.
there is more reasonable speculation about the effects of an intersection with the earths orbit leaving a trail of particulate that the earth would then pass through, and the unknown effects that would have. That is, however, only conjecture of late; the projected orbits and perihelions have changed drastically since its discovery in january 2011, so right now it is mostly speculation.