I was an astronomy buff, off and on, in my early teens (mid 1970s). The “Nemesis” hypothesis was very popular for explaining mass extinctions.
It went something like:
1. There are more binary star systems in the galaxy than single star systems.
2. The presence of a partner star to our Sun would cause a change in gravity affecting comets or larger asteroids as the two stars moved closer or farther apart.
3. Path changes in comets or large asteroids increase the possibility of collisions.
Now, this is what, 20 years before Hubble?
The Nemesis idea came about from the combination of apparent periodicity of mass extinctions and the Alvarez model. David Raup was one of the early participants, and has a couple of books about Nemesis and mass extinction. Richard Muller here:
http://www.freerepublic.com/focus/news/1962278/posts?page=46#46