[Primogenitor]

You have to make basic assumptions, such as constant decay. Given the assumptions are true, you can measure the decay in a certain time, say 5 minutes. You can then extrapolate that back into the past. Or forward into the future.

The assumptions you make can affect the result. There is also some uncertanty in any measurement of a continuous scale, such as time or distance. Thats why results are often given a margin of error. You could say the rock is 500 years of plus or minus 1 day. Thats quite accurate. Or it could be 500 years plus or minus 1000 years. Thats very inaccurate. If the assumptions are false, then the result will be wrong. In many cases, the assumptions made are known to be false, but are made in order to make it easier to work out. If you read a real science paper in a proper journal, such as Nature or Science or whatever, there are always certain assumptions whether declared or not. Those assumptions are based on previous work, which had assumptions based on previous work, etc. Right back to basics. You have to trust other peoples work.

I do think this forum has a large amount of christian background in it. It would be very nice to get some non-christian viewpoints and discussion. I think its fair to say that the majority of people reading this thread are aged 20-40, christian (if any religion), white european (including americans), male, educated to a reasonable level (just below Bachelor on average), and american or european, but i could be wrong.

[editied to raise age range as corrected by Ruatha]

[ May 20, 2003, 16:49: Message edited by: Primogenitor ]