Monday, April 26, 2010

Why Evolution is True - part 2

Continuing my notes as I read Why Evolution is True by Jerry Coyne.

There are creationist and then there are the 10,000 Year-Old-Earth-Creationists. It's one thing to deny such a well established theory as Darwinian evolution it's really another level of denial- ism to deny radioactive dating.

To me to say that radioactive dating is somehow wrong would mean that we don't fully understand the nucleus. That would mean that machines based on our understanding wouldn't work. Things like hydrogen bombs, nuclear power plants, MRI, etc. But those machines DO work so what the hell?

10,000 year old earth creationist have a neat way out of this. The claim is that we are miss-lead in our calculating the age of things via Carbon 14 or U235 dating because we assume the half-life of these unstable isotopes is the same now as it was then. They claim that it was different 'then' and leads to scientists grossly over calculating the age of things.

Two comments: 1. Can you show some factors that affect the half-life of an isotope? Such things as temperature, pressure, humidity? Answer: No. There are no separate experiments that suggest that half-life of an isotope depends on anything. 2. From 1 then, this is backwards thinking like a lot of creationist logic. They are starting with the earth is 10,000 years old as fact and then adjusting the half-life accordingly instead of just asking, 'How old is the earth?'.

But this argument from the creationist keeps re-appearing. In "Why Evolution is True" we have a wonderful way to knock all of this down. What if there was an independent way to show the age of something separate from radioactivity that then agreed with what radioactivity predicted? That would not only nail down the age of that thing but also show that the half-life is a constant and did not have different values at an earlier time.

There is a type of coral that radioactive dating puts at 380 million years ago. However, this coral also keeps its own calendar independently of this. We know the earth spins around ever slower due to the friction of the tides. In other words are days are getting longer at the rate of about 2 seconds every 100,000 years. Doing the math you find that 380 million years ago the day would have been much shorter and that there would have been 396 days in a year since the earth goes around the sun at a constant rate making all the years the same length of time. Now, these corals leave a yearly ring just like trees do but they also leave a daily ring. All you have to do is look at these fossils closely and count how many daily rings there are between two yearly rings. What do you get? About 400 putting the age of the corals at around 380 million years just as the radioactive data predicted.

Slam dunk.

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