MOONMOON

About:

• Name: In their paper on the preprint server arXiv.org, astronomers Juna Kollmeier and Sean Raymond have used the term “submoon” to describe a moon of a moon. Other scientists, however, have preferred “moonmoon”.
  
  
• Circumstances: For one to exist, very special circumstances would need to be place.
  • Mass: The host moon needs to have a sufficiently large mass, and the moonmoon must be sufficiently small.
    
    
  • Distance: The moonmoon needs to be close enough to the moon to be bound by its gravity, but not so close as to be torn apart by tidal forces. Also, both moons need to be far enough from the planet to prevent the moonmoon from being caught in the planet’s gravity, rather than the moons.
    
    
  
  
  
• Present status: No moonmoon is known to exist in the Solar System.