Bibliography

Physics for Scientists and Engineers 6th edition by Serway, Jewett

http://csep10.phys.utk.edu/guidry/violence/distances.html

http://whyfiles.org/071questions/10.html

http://www.crystalinks.com/pluto.html

http://math.ucr.edu/home/baez/physics/

http://www.theory.caltech.edu/people/patricia/st101.html