science wise 4.5 biliion years old, however there are no rocks that old because they go through the rock cycle. We can only guess this because we can "look back in time" at other planets.

As for the religious side- fossils were put on Earth by go to test our faith in Him.

I am not a religous freak- but I have to teach evolution and Earth Science in school so I get this alot.

Enjoy!