How old is the Earth?

[Statler Waldorf]

The assumption that decay rates have remained the same is based on sound science; namely, that we have done numerous things to radioactive materials (increased pressure, temperature, etc) and the decay rates has stayed the same.

What we should be asking is what evidence you provide that suggests the Earth is 6,000 years old (or however old you think it is). I only say 6,000 since you mentioned you believe God made it in 6 days, and when someone says that, they are usually a YEC.

I should also point out that you seem to misunderstand what an Ad Hominem attack is. If you insult someone in the middle of discourse, it is an insult, not an Ad Hominem. An Ad Hominem only occurs when you attempt to use the insult to somehow attack your opponent's argument (i.e. "You can't believe what he says because he's a moron.").

Well if the Earth is really 4.5 billion years old then you cannot "observe" that decay rates are constant because yoru observation is vastly too small and insignificant compared to the whole time period. Even if you could observe it for 100 years it would still only be 2.2X10^-11 percent of the total time. Even a curved line looks straight when you only observe an insignificant portion of it. So you're going to have to provide some other backing as to how you know those rates are constant.