Just some additional info to corroborate L. Ray's Nashville 08 reference to the Earth's long history and dinosaurs being killed about 65 million years ago due to a large cometary impact on earth. Here is a link to the site where i found i think a Gold mine on this subject: * religious links not allowed*
Geo.
Because of the original abundance of comets and other debris in the early Solar System, even Jupiter could not protect the Earth from the early cometary bombardment. However, this cometary bombardment was necessary to bring the water necessary for life to exist on the Earth. Collisions were so frequent on the early Earth that is is estimated that at least 30 large collisions (1) occurred that were energetic enough to vaporize the entirety of the Earth's oceans (in addition to much of its crustal rock) (2). However, once life was present on the Earth, the effect of cometary impact is devastating. It seems likely that the extinction of the dinosaurs was caused by the impact of a large meteor or comet with the Earth 65 million years ago.
References
Chyba, C. and C. Sagan. 1992. Endogenous production, exogenous delivery and impact-shock synthesis of organic molecules: an inventory for the origins of life. Nature 355: 125-132
Sleep, N.H., K.J. Zahnle, J.F. Kasting, and H.J. Morowitz. 1989. Annihilation of ecosystems by large asteroid impacts on the early Earth. Nature 342: 139-142.
Mr. Pacholka is a strong Christian believer and a friend of Reasons To Believe. More comet photos by Mr. Pacholka can be found at
www.newcreations.net/comet/index.html.