Oops! Check out this awesome explanation of how we effed up on an episode of SciShow. 

Hank continues our series on the four fundamental forces of physics with a description of gravitation -
the interaction by which physical bodies attract with a force proportional to that of their masses, and which is responsible for keeping planets in orbit, among other things.

Like SciShow on Facebook: http://www.facebook.com/scishow
Follow SciShow on Twitter: http://www.twitter.com/scishow