Are They Right?
No, even the creationists' own data undermines their claims. The
paper, titled HELIUM DIFFUSION RATES SUPPORT ACCELERATED NUCLEAR DECAY
is by D. Russel Humphreys, Steven A. Austin, John R. Baumgardner, and
Andrew A. Snelling <
http://www.icr.org/research/> (1.12 MB *.pdf)
All references in this post are to that paper.
The basic science involved is that fact that when a uranium atom
decays to lead, a lot of helium is produced, 8 helium atoms for every
atom of U-238 that decays to Pb-206 and 7 helium atoms for each atom
of U-235 decaying to Pb-207. The creationist claim to have found
some zircons (tiny crystals of ZrSiO4 in rocks) which have TOO MUCH
helium. The zircons were dated to 1.5 BY using the Pb-Pb method, but
according to the creationists, the helium produced by the decays
should have all leaked out of the zircons by now. The creationists
claim that the zircons could retain their helium for only about, you
guessed it, 6000 YEARS!
The zircons were found at various depths, and the deeper rocks were
hotter and had less helium, as you would expect since helium leaks out
faster at higher temperatures. Here are their numbers taken from
their TABLE 1
Number Depth (m) Temp C Helium (%)
1 960 105 58 +- 17
2 2,170 151 27 +- 8
3 2,900 197 17 +- 5
4 3,502 239 1.2 +- 0.4
5 3,930 277 ~0.1
6 4,310 313 ~0.1
The column "Helium %" gives the amount of helium found in the zircons
as a percentage of the amount of helium that would have been produced
in 1.5 BY of radioactive decay. In samples 4, 5, and 6 the amount
of helium is so low as to be almost unmeasurable (the "~" sign means
"approximately"), but the first three samples, which are all below 200
C, still have a substantial fraction of the expected amount of helium.
The creationists have a logical problem. If the zircons were only
6,000 years old, then the helium could not have been produced by 1.5
BY of radioactive decay, so we have no explanation for the presence of
the helium. Worse, we would have no idea of how much helium "ought"
to be present, so we couldn't tell how much helium has leaked out.
The solution is, of course, a miracle. The "creation" model assumes
that 1.5 BY worth of radioactive decay actually occurred in the
zircon, but God, or perhaps Billy Graham, miraculously "accelerated"
the decays so they all happened in an interval much less than 6,000
years.
This "solution" leads to another logical problem. Suppose the
creation are right. Then presumably these miraculously accelerated
decays would have occurred in all the world's rocks, not just in a few
zircons. There are rocks with radioactive dates of all ages, from the
geologically recent up to 3.8 billion years, so if the earth is
really only 6,000 years old, then different rocks must have been
"aged" by very different amounts. And the amount of "aging" was
deliberately chosen so that rocks near the top of the geologic column
were given young ages, while deeper rocks were made to look older. So
God first endowed the earth with many major features implying great
age (continental drift, vast layers of sedimentary rocks, long
vanished mountain ranges, enormous "batholiths" of solidified magma)
and then added in many subtle indicators of age such as radioactive
decay, magnetic field reversals, Milankovich cycles, etc. And ALL of
these feature are FAKES, the only sign of the true age of the earth is
given by the amounts of helium, which God apparently overlooked. So
unless earth's history was controlled by a "fakey-flakey" Creator,
there is no way the creationists can be right!
Apparently the 4 devout Christians authors would rather believe in a
Supreme Being who plays silly God tricks with the universe, instead of
admitting that their ploddingly literal minded interpretation of a few
phrases in Genesis is wrong. Hubris, anyone?
But enough about logic, let's get down to the "facts." To proceed we
need two numbers. The first is the diffusion coefficient D which
measures how fast helium diffuses through the zircons. This can only
be obtained by measurement. The second number comes from a
theoretical calculation which gives the relationship between D and the
actual age of the zircons.
The authors have made a real effort to make the paper look good.
There is a nice explanation of diffusion, and the theoretical
calculation is described in loving detail. They display the
equations used, give references to where they got the equations, and
say they used Mathematica to solve them. (The fact that all they did
with Mathematica was to sum a series of positive numbers suggests they
didn't know how to write even an elementary computer program, but they
mean it to be impressive.)
As for the measurements of D, the creationists didn't do the
measurements themselves, they got an expert to do the measurements for
them. The creationists contacted the expert through a front man who
didn't tell the expert who the measurements were for, or why they
wanted them. All very wise, and confidence building, precautions.
But then a problem arises and is promptly swept under the rug. The
creationists prominently display the result of their theoretical
calculations i.e. they explicitly say what D should be if the zircons
are either 6,000 years old (Table 2) or 1.5 BY old (Table 3). The
problem comes in the comparison of theory and measurement.
What the creationists do is hide behind a technical difficulty. The
diffusion coefficient D changes dramatically with temperature, and the
measurements of D were all done at temperatures of 300 - 500 C. But
the good (or at least "better") zircons were below 200 C so one has to
extrapolate down to these lower temperatures. (The measurement
procedure is to heat the zircons and see how much helium leaks out at
different temperatures. The reason for the heating is that helium
leaks out too slowly at low temperatures.)
So if you extrapolate down to 197, 151, and 105 C, what do you get?
As the creationists say, D depends on T as:
D = D0exp( -E0 / (RT) ) (Eq 2 in the creationist paper)
where R is the universal gas constant 1.986 calories / mole-degree, T
is temperature in degrees Kelvin (Kelvin equals Centigrade + 273) and
D0 and E0 are constants that are found by "fitting" Eq. 2 to the
measurements. Even though the creationists don't say what D is at the
relevant temperatures, they do give values of D0 and E0, so we can
calculate D for ourselves.
In fact there are TWO sets of values for D0 and E0, the first was
calculated using all the measurements and the second using only the
lower part of the temperature range (300 - 440 C). There are reasons
why the temperature curve may "flatten out" at lower temperature,
i.e. D doesn't change as fast with temperature when the temperature is
lower, so a calculation using only the lower temperatures may be more
accurate. (I suppose that's the reason for the two different results).
The results are:
For ALL temperatures :
E0 = 34,400 D0/a^2 = 3548 + 3100 - 1700 (Eq. 5a)
For 440-300 C
E0 = 29,400 D0/a^2 = 64.9 (Eq. 5b)
"a" is the radius of the zircons, the zircons were assumed to be
spheres with 30 micron radius. Since 30 microns is 0.003 cm, 1/a^2
= 111,111 = 1.1 x 10^5. Note the large (factor of 2) error bar on
D/a^2 from 5a, and the ABSENCE of errors on the other 3 parameters.
Using the two different values of D0 and E0 in equation 2 we get:
Temp (C) D(6,000 years) D(all temp) D(440-300 C)
105 3.2 x 10^(-18) 4.1 x 10^(-22) 5.7 x 10^(-21)
151 1.3 x 10^(-17) 5.8 x 10^(-20) 4.0 x 10^(-19)
197 2.2 x 10^(-17) 1.0 x 10^(-18) 1.2 x 10^(-17)
239 1.8 x 10^(-16) 6.5 x 10^(-17) 1.6 x 10^(-16)
277 9.7 x 10^(-16) 6.7 x 10^(-16) 1.2 x 10^(-15)
(The creationists decided to drop the zircon measurement at 313 C,
that's why it doesn't appear here.)
If we compare the two columns of measured values, i.e D(all temp) and
D(440-300 C) we see that they disagree by a factor of 2 at 277 C and a
factor of 14 for the sample at 105 C! We are not doing precision
science here. The measured values agree roughly (within a factor of
2) with the theory at 277 C but are far smaller at 105 C.
Let's accept the Creationists' claim that their theoretical
calculations really do correspond to an age of 6,000 years and see
what ages are implied by the MEASURED values. This is the table that
the Creationists SHOULD have put in their paper, but didn't.
Temp (C) Age (all temp) Age (440-300 C)
105 46,800,000 3,400,000
151 1,350,000 195,000
197 132,000 11,000
239 16,600 6,750
277 8,700 4,850
So what do the creationists show in their paper? In their Table 4
they quote THREE of the 10 ages given above. (They do a pointless
song and dance about a quantity "x" but what it boils down to is they
quote 3 of the ages.) Which three ages do they pick? The lower 3 from
the right hand column, i.e. 4,850, 6,750, and 11,000. (Their values
are 4,747, 6392, and 10,389, which are different from mine because
they were more fussy than I was about typing in all the decimal places
into the calculator. It doesn't matter since the error bars are about
a factor of two.) So the creationists show the ages they like and
don't show the ones they don't like. Yes, this is UNETHICAL.
If we choose to believe that the numbers in the paper are more honest
than the paper's authors, we can ask what these ages mean. Let's
focus on two questions. The first question is whether these data
actually provide any support for the claim that the earth is 6,000
years old. The second question is whether these data are any sort of
embarrassment to the standard view about the age of the earth. Note
that the second question is NOT just a restatement of the first. The
standard view is supported by vast amounts of high quality evidence of
many different sorts, none of this evidence is going to disappear just
because some zircons have too much helium. But unless these zircons
really do support 6,000 years, the creations claim has NO basis in
fact.
Do the zircons provide any evidence for 6,000 years? The high
temperature zircons give young ages, but their helium content is quite
low, which means the helium could easily be due to measurement error
or contamination. After all, if a zircon has no helium, then the only
age determination possible is a lower limit: i.e. all you can say is
that the zircons have to be old enough so that all the helium could
have leaked out. Lower limits on age don't do the creationists any
good.
The cold zircons have much more helium, so their helium measurements
are presumably more reliable, but they give ages that are much larger
than 6,000 years, and the colder, the older. What does this mean?
The best the creationists can do is suggest that at lower temperatures
the diffusion constant D doesn't decrease as rapidly as at high
temperatures so extrapolating down from high temperatures
underestimates D and therefore overestimates the age. That could be
true, but the creationists themselves admit they DON"T HAVE ANY DATA
below 300 C, so extrapolating down from high temperatures to low
temperatures is all they have to offer.
Faced with age estimates from their own data which differ by a factor
of 10,000 (4,850 to 46,800,000) the creationists need to get their
house in order before they can throw stones at anyone else's. In the
present paper, the creationists position boils down to saying:
"Please, please believe in the small ages that we like, and not the
big ages that we don't like."
Could helium diffusion measurements be an embarrassment for the
conventional view of the age of the Earth? Potentially, yes. (That's
why the creationists are doing the measurements in the first place).
But to achieve their goal, the creationists need good (or at least
consistent) data, honestly analyzed. Until then, they embarrass no
one but themselves.