Sitchin claims that the Babylonians associated Nibiru with the god Marduk; the word is Akkadian and the meaning is uncertain. Sitchin hypothesized it as a planet in a highly elliptic orbit around the Sun, with a perihelion passage some 3,600 years ago and assumed orbital period of about 3,750 years; he also claimed it was the home of a technologically advanced human-like alien race, the Anunnaki, who apparently visited Earth in search of gold. These beings eventually created humanity by genetically crossing themselves with extant primates, and thus became the first gods.