REFERENCIAS:

 

http://www.nasa.gov/audience/forstudents/k-4/stories/nasa-knows/what-is-pluto-k4.html

 

http://www.nasa.gov/image-feature/new-horizons-close-up-of-charon-s-mountain-in-a-moat

 

http://lowell.edu/in-depth/pluto/

 

http://lowell.edu/in-depth/pluto/pluto-research-at-lowell/

 

http://www.nasa.gov/vision/universe/solarsystem/erisf-20060914.html