Zecharia Sitchin is an author of books promoting the ancient astronaut theory of human origins. He attributes the creation of the ancient Sumerian culture to the "Annunaki" (or "Nephilim"), a race of aliens from an undiscovered planet named Nibiru in the Earth's solar system. He asserts that Sumerian mythology reflects this view, though his speculations are entirely discounted by mainstream scientists and historians who see many problems with his translations of ancient texts and with his understanding of physics.