I don’t know if this guy is serious– he seems to be– but he has an entire website dedicated to the belief that “Planet X” is about to pass close by, causing untold problems.
This leads to a possible question for the assembled:
Which old SF flick would you like to live through? Why? How would we cope?
My General Relativity prof once told me that the best thing about researching G.R. is that the math scares away the crackpots.