Nibiru

I have noticed there are a lot of discussions on this forum with
people who are called "Zetas". Correct me if I am wrong: They are
people who believe in a planet x from their discussions, and, this
planet x is a yet discovered 12th planet in our solar system. I get
the impression that it is what I have read about on the net concerning
alternative archaeology called Nibiru, which, I get the impression was
a theory started by Zacharia Sitchin, a scholar who claimed to be the
only person (at the time) who could read and understand Ancient
Sumerian Cuneiform. As I understand it, when he translated Ancient
Sumerian Cuneiform, he found that the Sumerians had a creation myth
where people came from the sky (extraterrestrials) and they created us
(genetic engineering). I further understand that Sitchin says these
extraterrestrials came from a planet called Nibiru. Now, as I see it,
these Zetas understand science, but practice alternative science. The
concept that we were genetically engineered by extraterrestrials also
claims from what I have read on the net comes from a combining of
their genes with an ancient ancestor, I think they say with Homo
Erectus, which I understand left Africa 2 million years ago. Homo
Sapiens go back 500 thousand to one million years ago. Now I read
science fiction, and a lot of it is Arthur C. Clarke. I am sure you
are all familiar with him. He wrote 2001: A Space Odyssey, with
Stanley Kubrick. If you have read the sequels, and don't read any
further if you don't want me to spoil the sequels for you, he had that
advanced intelligence from elsewhere in the Universe made the early
hominid ancestors that eventually evolved into humans. The concept, of
course is not ludicrous, but of course at this point it is pure
speculation and I think the geologic record clearly shows humans as
descendent from simpler and simpler life forms over hundreds of
millions of years. But, I know the Zetas argue here, and many others
elsewhere, scientifically on this issue. And that brings me to what I
am getting at. If they are scientific, then surely they have an
argument for the first most obvious question: If there is life on a
twelfth planet more advanced than ourselves, how that be? And I ask
because anything beyond Pluto would be so far from the sun that it
would be too cold for life to evolve there. I have asked this question
to a Zacharia Sitchin Forum, and no one ever posted a reply. I wrote
to a scholar on the subject, and he never returned my e-mail.
Certainly people who believe in this have their explanation for such a
question. Perhaps someone here at sci.astro will know what that
explanation is.