Those anxiously awaiting the return of Nibiru are, whether they know it or not, continuing the legacy of Russian-born author Zechariah Sitchin, whose 1976 bestseller The 12th Planet – and five subsequent follow-ups – provide the core framework for the Nibiru myth.

Sitchin’s version of humankind’s origins shares its basic ancient astronaut premise with the work of Erich von Däniken, but is as intricate and involved as history itself, spanning almost half a million years and our entire Solar System. It goes something like this:

Facing extinction on their home planet of Nibiru 450,000 years ago, the deposed ruler of a race known to mythology as the Anunnaki, the Elohim or the Nefilim, travels to Earth. Establishing a base known as Eridu, the Anunnaki arrive in droves and begin mining Earth’s gold (used to restore Nibiru’s failing atmosphere), with the help of a slave race – us humans – genetically modified from apes about 300,000 years ago. About 100,000 years ago the Anunnaki started interbreeding with humans – as related in the Bible – leading to schisms within the various Anunnaki dynasties, who between them founded all our ancient civilizations. It all comes to an unpleasant end in 2024BC when, after much inter-clan feuding, nuclear war breaks out between the Anunnaki, resulting in the annihilation of the great Sumerian civilization.

Central to the story is the long orbit of Nibiru (“Planet of the Crossing”) around our shared Sun every 3,600 years. Each time it passes close to the Earth, our planet is wracked by natural catastrophe, the most famous being the Great Flood, survived only by Noah, his family and their menagerie (or Utnapishtim in the Epic of Gilgamesh). While Sitchin himself has not claimed that Nibiru is Planet X, or that it is even heading our way any time soon, his books form the gnarled roots of the current planet panic.

But researchers such as astronomer Phil Plait and Michael Heiser, a scholar of ancient languages, have highlighted several serious problems with Sitchin’s theory.

The theory revolves around one Sumerian seal, VA 243, which Sitchin claims demonstrates the advanced astronomical knowledge passed on to the Sumerians by the extraterrestrial Anunnaki. In it can be seen what Sitchin claims to be our Sun, surrounded by 11 “planets”. The Sumerians considered the Sun and Moon to be planets (hence the “12th Planet” of the title), leaving one planet in our Solar System that is unaccounted for – Nibiru or Planet X.

Michael Heiser identifies several problems with Sitchin’s interpretation of this seal:

• From its inscription, it appears that the seal has nothing to do with astronomy. Instead it reads: “Dubsiga, Ili-illat, your/his servant”.

• The symbol Sitchin takes to be the Sun does not correspond to any other Sun symbol in the hundreds of known Sumero-Mesopotamian documents, seals or artworks. In fact it is a common star, for which there was a clearly different symbol. The Sun is always either shown as a disc with four arms and wavy lines, or just wavy lines emanating from it. The symbol in VA 243 has only four arms, and no wavy lines, in common with other representations of stars.

• No contemporary texts exist that suggest that
the Sumerians or Mesopotamians knew of more than five planets: Mars, Venus, Jupiter, Saturn and Mercury.

• While the word Nibiru has the idea of “crossing” as its root meaning, used, for example, to refer to bridges or gates, in astronomical texts it refers to a planet. This is usually Jupiter but is also sometimes Mercury, another star, or the God Marduk. It certainly is never used to refer to a planet beyond those known to the culture of the time.

As Heiser concludes: “Sitchin’s entire system is wrong – you either believe the Sumerians or him”

There are also astronomical problems with the 12th Planet hypothesis – aside from the fact that, despite its being four times the size of Earth (at least according to Nancy Lieder), no astronomer has seen Nibiru yet.

For example, if the Sumerians gained their astronomical knowledge from technologically advanced aliens, it seems odd that they refer to Earth’s Sun and Moon as planets, but not, for instance, Jupiter’s many moons. Sitchin’s inclusion of Pluto as one of the 12 planets is also questionable. Pluto’s status as a planet has come under considerable doubt in recent years, with many astronomers calling for it to be relegated to the status of a large asteroid or Kuiper-belt object, alongside the recently discovered Quaoar and Varuna.

It seems a remarkable coincidence that millennia-old space gods should share their inconsistencies in planet identification with early 20th century humans. But somehow The 15th Planet, or indeed The 11th Planet, just don’t sound quite right.