no its not an ufo mother ship..
they say it is the 10th planet,
which used to br in our solar system,, but went of track and since that happend it comes like every 3600 years,
Zecharia Sitchin who is an archeologist,, who translated the sumarian language
and has been translating old texts,, but any way,, I find this really interesting it makes much more sense if this is supposed to be like this,, cause the life as we know it, the life that we live, has a lot of puzzles to solve........
if you are not intrested do not watch this
but if you are,, I recommend you to watch all 4 parts of that documentary
http://www.youtube.com/watch?v=UKwfS6zug_g