Conversation:

I was thinking of making Nemesis the subject of my first guide entry, but I see you have discussed it here already. I find it fascinating and enjoyed your entry.

It's an entertaining theory, but there is very little evidence to support it.

A respected astronomer (Dr Cathy Imhoff of the Space Telescope Science Institute) contributed an article to a learning resource managed by Scholastic Inc. that pretty much settles the issue of the fabled Planet X or Nemesis.

There are no other planets in the solar system. It should be noted that this does not rule out the existence of the Oort cloud, only the the mysterious planet.

BTW who suggested that most stars are binaries?

An alternative theory on the Nemesis cycle is that it is related to periodic passage of the solar system through the matter rich region in the plane of the ecliptic of the galaxy, since the periodicity matches that of the succession of the geological ages and the mass extinctions.