Stichen was wrong about Niburu, so what does it matter what he said about it?
A number of Zecharia Sitchin's fans have been asking about the date December 21, 2012 and what it might signify in relation to Zecharia's writings. Zecharia would have suggested to any posing such a question that you "read my book". In this case, read The End of Days.
It is gratifying that Wikipedia lists one of the possible reasons for the significance of the date as the passing of Nibiru, a planet that would not be named without Zecharia's work. However, since I am not Zecharia, I'll give away a bit of the puzzle and say that neither cataclysmic events on December 21, 2012 nor Nibiru come into play as a concern in 2012. For more details, read the book. J.Sitchin - July 2011
After Lieder, the first person to propagate her Planet X idea was Mark Hazlewood, a former member of the ZetaTalk community, who in 2001 published a book: Blindsided: Planet X Passes in 2003. Lieder would later accuse him of being a confidence trickster. A Japanese cult called the Pana Wave Laboratory, which blocked off roads and rivers with white cloths to protect itself from electromagnetic attacks, also warned that the world would end in May 2003 after the approach of a tenth planet. Roughly a week before the supposed arrival of Planet X, Lieder appeared on KROQ-FM radio in Los Angeles, and advised listeners to put their pets down in anticipation of the event. When asked if she had done so, she replied that she had, and that "The puppies are in a happy place." She also advised that "A dog makes a good meal". After the 2003 date passed without incident, Lieder said that it was merely a "White Lie ... to fool the establishment," and said that to disclose the true date would give those in power enough time to declare martial law and trap people in cities during the shift, leading to their deaths. Many Internet sites continue to proclaim that Lieder's object is en route to Earth, often citing its arrival date as December, 2012. This date has gathered many apocalyptic associations, as it is the end of the current cycle (baktun) in the long count in the Mayan calendar. Several writers have published books connecting the encounter with 2012.
Although Lieder originally referred to the object as "Planet X", it has become deeply associated with Nibiru, a planet from the works of ancient astronaut proponent Zecharia Sitchin, particularly his book The 12th Planet. According to Sitchin's interpretation of Babylonian religious texts, which contradicts conclusions reached by credited scholars on the subject, a giant planet (called Nibiru or Marduk) passes by Earth every 3,600 years and allows its sentient inhabitants to interact with humanity. These beings, which Sitchin identified with the Annunaki of Sumerian myth, would become humanity's first gods. Lieder first made the connection between Nibiru and her Planet X on her site in 1996 ("Planet X does exist, and it is the 12th Planet, one and the same."). However, Sitchin, who died in 2010, denied any connection between his work and Lieder's claims. In 2007, partly in response to Lieder's proclamations, Sitchin published a book, The End of Days, which set the time for the last passing of Nibiru by Earth at 556 BC, which would mean, given the object's supposed 3,600-year orbit, that it would return sometime around AD 2900. He did however say that he believed that the Annunaki might return earlier by spaceship, and that the timing of their return would coincide with the shift from the astrological Age of Pisces to the Age of Aquarius, sometime between 2090 and 2370.