Works Cited :D : trabajos citados
http://science.howstuffworks.com/dictionary/astronomy-terms/galaxy3.htm
http://hubblesite.org/hubble_discoveries/discovering_planets_beyond/how-do-planets-form
http://science.howstuffworks.com/dictionary/astronomy-terms/big-bang-theory2.htm
http://www.space.com/13320-big-bang-universe-10-steps-explainer.html
http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml
Physical Sciences with Earth Science by Glencoe- Book
http://hubblesite.org/hubble_discoveries/discovering_planets_beyond/how-do-planets-form
http://science.howstuffworks.com/dictionary/astronomy-terms/big-bang-theory2.htm
http://www.space.com/13320-big-bang-universe-10-steps-explainer.html
http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml
Physical Sciences with Earth Science by Glencoe- Book