It also happens when you search for "Eclipse". I did it this morning and on the bottom of the results I got :

Searches related to: eclipse
eclipse paintball solar eclipse lunar eclipse eclipse aircraft
eclipse navigation myeclipse eclipse tutorial eclipse burner

I've been seeing these for a while now. For example:

Searches related to: Tampa Bay
tampa bay beaches tampa bay devil tampa bay florida tampa bay hotels
tampa bay history tampa bay attractions tampa bay mlb tampa bay weather

Thanks Phillipp for all your great post's and I am just happy I could be of some help!!!

Keep up the good work!

Joe Whyte

Sport, tech, comic, superhero, movie, life trigger related searches too... "life" for example results in:

life quotes - meaning of life - life poems - life cereal –
life eddie murphy - definition of life - lifeway - lyfe

I wonder how Google determines when to display the related searches "downbox"?