[RadioAstronomer]

such as, oh, particles that have a half life in the fractions of a second leaving halos of decay in bedrock

More codswallop.

http://www.talkorigins.org/faqs/po-halos/

[Havoc]

Right, essentially you want to argue that the polonium in the rocks surrounded by the halos didn't cause their own halos and that plutonium or something else might have caused it though there's no evidence of that. Right. Exactly the type of proofs we've come to expect. Aliens must have done it cause it conflicts with our theory and that just can't stand.