The 2012 phenomenon comprises a range of eschatological beliefs according to which cataclysmic or transformative events will occur on 21 December 2012. This date is regarded as the end-date of a 5125-year-long cycle in the Mesoamerican Long Count calendar. Various astronomical alignments and numerological formulae have been proposed as pertaining to this date, though none have been accepted by mainstream scholarship.
A New Age interpretation of this transition is that the date marks the start of time in which Earth and its inhabitants may undergo a positive physical or spiritual transformation, and that 21 December 2012 may mark the beginning of a new era. Others suggest that the date marks the end of the world or a similar catastrophe. Scenarios suggested for the end of the world include the arrival of the next solar maximum, an interaction between Earth and the black hole at the center of the galaxy, or Earth's collision with a planet called "Nibiru".
Scholars from various disciplines have dismissed the idea of such cataclysmic events occurring in 2012. Professional Mayanist scholars state that predictions of impending doom are not found in any of the extant classic Maya accounts, and that the idea that the Long Count calendar "ends" in 2012 misrepresents Maya history and culture, while astronomers have rejected the various proposed doomsday scenarios as pseudoscience, stating that they conflict with simple astronomical observations.