•  December 2012 has blossomed into a major new presence on the Internet. This fear has begun to invade cable TV and Hollywood, and it is rapidly spreading internationally. The hoax originally concerned a return of the fictitious planet Nibiru in 2012, but it received a big boost when conspiracy theory websites began to link it to the end of the Mayan calendar long count at the winter solstice (December 21) of 2012. Over the past year, many unrelated groups have joined the doomsday chorus, including Nostradamus advocates, a wide variety of eschatological Christian, Native American, and spiritualist sects, and those who fear comet and asteroid impacts or violent solar storms. At the time of this writing there are more than 175 books listed on Amazon.com dealing with the 2012 doomsday. The most popular topics are the Mayan calendar and spiritual predictions that the disaster in 2012 will usher in a new age of happiness and spiritual growth. Quite a few authors are cashing in with manuals on how to survive 2012. As this hoax spreads, many more doomsday scenarios are being suggested, mostly unrelated to Nibiru. These include a reversal of the Earth’s magnetic field, severe solar storms associated with the 11-year solar cycle (which may peak in 2012), a reversal of Earth’s rotation axis, a 90- degree flip of the rotation axis, bombardment by large comets or asteroids, bombardment by gamma rays, or various unspecified lethal rays coming from the center of the Milky Way Galaxy or the “dark rift” seen in a nearby galactic spiral arm. A major theme has become celestial alignments: supposedly the Sun will align with the galactic center (or maybe with the Milky Way Dark Rift) on December 21, 2012, subjecting us to mysterious and potentially deadly forces. Unlike most pseudoscience stories, there seems to be no factual core on which the Nibiru- 2012 hoax has been constructed. This is different from, for example, the claims of aliens and a crashed UFO at Roswell, New Mexico. The alien stories are a fabrication, but the core fact is that an instrumented balloon did crash in Roswell on July 7, 1947. There is no similar factual core to Nibiru—just dubious “predictions” from psychics, or the Mayans, or Nostradamus. The rest is pure fiction. I answer questions from the public submitted online to a NASA website, and over the past two years the Nibiru-2012 doomsday has become the dominant topic people ask about. Many are curious about things they have seen on the Internet or TV, but many are also angry about supposed government cover-ups. As one wrote “Why are you lying about Nibiru? Everyone knows it is coming.” Others are genuinely frightened that the world will end just three years from now. My frustration in answering questions piecemeal motivates this “Twenty Questions” format to organize the facts and shine a skeptical light on this accumulation of myths and hoaxes. 1. What is the origin of the prediction that the world will end in December 2012? The story started with claims that Nibiru, a supposed planet discovered by the Sumerians, is headed toward Earth. Zecharia Sitchin, who writes fiction about the ancient Mesopotamian civilization of Sumer, claimed in several books (e.g., The Twelfth Planet, published in 1976) that he has found and translated Sumerian documents that identify the planet Nibiru, orbiting the Sun every 3600 years. These Sumerian fables include stories of “ancient astronauts” visiting Earth from a civilization of aliens called the Anunnaki. Then Nancy Lieder, a self-declared psychic who claims she is channeling aliens, wrote on her website Zetatalk that the inhabitants of a fictional planet around the star Zeta Reticuli warned her that the Earth was in danger from Planet X or Nibiru. This catastrophe was initially predicted for May 2003, but when nothing happened the doomsday date was recalculated (a standard procedure for doomsdayers) and moved forward to December 2012. Only recently have these two fables been linked to the end of the Mayan long-count at the winter solstice in 2012—hence the predicted doomsday date of December 21, 2012. 2. The Sumerians were the first great civilization, and they made many accurate astronomical predictions, including the existence of the planets Uranus, Neptune and Pluto. So why should we not believe their predictions about Nibiru? Nibiru is a name from Babylonian astrology sometimes associated with the god Marduk. Nibiru appears as a minor character in the Babylonian creation poem Enuma Elish as recorded in the library of Assurbanipal, King of Assyria (668–627 BCE). Sumer flourished much earlier, from about the 23rd century to the 17th century BCE. The claims that Nibiru is a planet and was known to the Sumerians are contradicted by scholars who (unlike Zecharia Sitchin) study and translate the written records of ancient Mesopotamia. Sumer was indeed a great civilization, important for the development of agriculture, water management, urban life, and especially writing. However, they left few astronomical records and they most certainly did not know about Uranus, Neptune or Pluto. They also had no understanding that the planets orbited the Sun, an idea that first developed in ancient Greece two millennia after the end of Sumer. Claims that Sumerians had a sophisticated astronomy, or that they even had a god named Nibiru, are the product of Sitchin’s imagination. 3. How can you deny the existence of Nibiru when NASA discovered it in 1983 and the story appeared in leading newspapers? At that time you called it Planet X, and later it was named Xena or Eris. IRAS (the NASA Infrared Astronomy Satellite, which carried out a sky survey for 10 months in 1983) discovered many infrared sources, but none of them was Nibiru or Planet X or any other objects in the outer solar system. Briefly, IRAS cataloged 350,000 infrared sources, and initially many of these sources were unidentified (which was the point, of course, of making such a survey). All of these observations have been followed up by subsequent studies with more powerful instruments both on the ground and in space. The rumor about a “tenth planet” erupted in 1984 after a scientific paper was published in Astrophysical Journal Letters titled “Unidentified point sources in the IRAS minisurvey,” which discussed several infrared sources with “no counterparts.” But these “mystery objects” were subsequently found to be distant galaxies (except one, which was a wisp of “infrared cirrus”), as published in 1987. No IRAS source has ever turned out to be a planet. A good discussion of this whole issue is to be found on Phil Plait’s website. The bottom line is that Nibiru is a myth, with no basis in fact. To an astronomer, persistent claims about a planet that is “nearby” but “invisible” are just plain silly. 4. Maybe we should be asking about Planet X or Eris, not Nibiru. Why does NASA keep secret the orbit of Eris? “Planet X” is an oxymoron when applied to a real object. The generic term has been used by astronomers over the past century for a possible or suspected object. Once the object is found, it is given a real name, as was done with Pluto and Eris, both of which were once referred to as Planet X. If a new object turns out to be not real, or not a planet, then you won’t hear about it again. If it is real, it is no longer called Planet X. Eris is one of several dwarf planets recently found by astronomers in the outer solar system, all of them on normal orbits that will never bring them near Earth. Like Pluto, Eris is smaller than our Moon. It is very far away, and its orbit never brings it closer than about 4 billion miles. There is no secret about Eris or its orbit, as you can easily verify by googling it or looking it up in Wikipedia