[asa] Oklo as the graveyard of YEC

OK, the subject line is an overstatement (only because of the invincible
ignorance of some YECs), but not much.

Dave Siemens pointed out in a recent post here that the Oklo natural
reactors present convincing evidence that the earth is at least ~2 x 10^9 yr
old. That's true but Oklo in fact provides a much more compelling argument
against YEC, and, in particular, against "apparent age" arguments.

The present U-235/U-238 ratio, about 1/138, together with the known half
lives of the 2 isotopes, gives an elapsed time since their formation of
about 4.9 Gyr if the initial isotopic ratio was 1. Nuclear theory indicate
that the ratio formed by r-process in the late stages of stellar evolution
should have been more like 1.65, to the age would be greater, something more
than 5.9 Gyr. That would be the time since the uranium that went into the
solar system was ejected into the interstellar medium by supernovas. 5.9
Gyr is a minimum, which would be the correct value if all the solar system's
uranium came from one SN. If it comes from more than one then the age could
be greater.

Now the dodge that's often been used to avoid such arguments is "apparent
age": God made the world 6000 (or whatever) years ago with an isotopic
ratio to make it look much older if one uses "uniformitarian" assumptions.
& to deflect the point that this makes God the creator of a deception, it's
said that creation of a fully-formed universe would have to have apparent
age: There have been debates about this here with appeals to the properties
of the wine created at Cana in support of such ideas.

Now there are some properties that a fully formed creation would have to
have, though it's hard to see why a 325/238 ratio of 1/138 would be one of
them. But let that pass. We now have to consider Oklo. The 235/238 ratio
there is slightly less than the value in the rest of the world, the first
clue that there were in fact natural reactors operating there some time ago.
In order for chain reactions to be sustained with ordinary water as a
moderator, the uranium would have had to be at least 3% U-235, and we can
calculate back to see when that would have been the case - about 1.7 Gyr
ago.

In order for the apparent age argument to work now, one has to argue not
only that God, for some unknown reason, made the uranium in the world have
an isotopic ratio indicating an age of ~ 6 Gyr for the solar system. God
would also have had to tweak this ratio a bit at once locale in west Africa
to make it look as if natural reactors were operating there around 2 Gyr
ago, even though no such thing ever really happened.

Some people are able to swallow the traditional apparent age argument, but
it seems to me that such a fine tuning of apparent age can be accepted only
if one is willing to drop all the arguments about fully formed creation and
just say flat out that God did it to deceive people. I'm sure that some
YECs will be willing to do that, but there are others with enough
theological integrity finally to realize that there must be another way -
like believing what the creation itself tells us about its age.

Shalom
George
http://web.raex.com/~gmurphy/

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Received on Sun Apr 15 16:52:24 2007