In prehistoric times, dinosaurs were so massive that archeologists wonder how they were not crushed under their own weight.
Could the Earth rotate fast enough to make everything considerably lighter and retain an atmosphere?
Could the slowing of the rotation cause extinction among the larger animals in the future if an asteroid hit the Earth at such angle as to slow its rotation?
Update: This question did not do well here and I have written it here. Both answers were up voted by me. https://earthscience.stackexchange.com/questions/13432/what-is-the-fastest-the-earth-has-ever-spun