Introducing a new debate topic, this one from the Creationist perspective:
Scientific measurements of the sun's diameter have found that it is shrinking at a slow but steady rate, so 6000 years ago when the earth and sun were created it would have been only slightly larger than it is now. But 20 million years ago it would have been huge, as big as the earth's orbit. It would have burnt the earth to a cinder. For this reason, the earth and sun cannot possibly be that old.
--Percy