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Tuesday, September 23, 2014

Will This Bring Back the Moon Dust Argument?

Posted by jlwile on January 22, 2014

This NASA photo shows the thin layer of dust on the moon.  (public domain image)

This NASA photo shows the thin layer of dust on the moon. (public domain image)

Answers in Genesis keeps a list of creationist arguments that should never be used. It is a good list, and I am glad that Answers in Genesis maintains it. It would be nice if an evolutionary source did the same thing. I don’t know how many times I have to refute nonsense like vestigial tails, lanugo hair, vestigial hair, the vestigial appendix, junk DNA, and all manner of evolutionary arguments that are simply not consistent with the data we currently know.

In any event, the first item on the list of creationist arguments that should never be used is the Moon Dust Argument. In brief, the argument used an estimate of how quickly dust accumulates on the moon to calculate how much dust the astronauts should have found when they landed there. It claims that if the moon were really billions of years old, there should be more than 100 feet of dust on its surface. Astronauts found only a thin layer of dust when they landed, so the moon is not billions of years old.

The problem with that argument rests on the estimate for how quickly dust accumulates on the moon. It was based on how quickly dust accumulates on earth. Obviously, the earth is quite different from the moon, so it’s not clear how good such an estimate is. In addition, other estimates have been made using other methods, and those estimates mostly disagree with one another. Since there seemed to be no good way of estimating how quickly dust accumulates on the moon, responsible creationists stopped using the argument, and that’s how it ended up on the Answers in Genesis list of arguments that should never be used.

Well, some interesting experiments have been done to provide a more direct measurement of dust accumulation on the moon, and the results are surprising, at least to those who are committed to an old earth.

In 1969, the Apollo 11 crew left a device containing solar cells and thermometers on the moon. Its job was to measure moon dust accumulation. Essentially, it sent data back to the earth indicating the voltage it was producing. As moon dust accumulated, it would block light from the solar cell, reducing the voltage. Later Apollo crews left similar devices behind, and as a result, NASA had a lot of data regarding how the solar cells lost voltage over time. Those data, however, were lost. Well, they have recently been recovered, so Monique Hollick and Brian J. O’Brien (the inventor of the devices left on the moon) have decided to analyze the data.

Of course, there is a problem. While it is clear that dust accumulation reduces the voltage of the solar cells, there is no way to convert the loss of voltage into a specific thickness of dust. However, experiments were done back on earth where fake moon dust was sprinkled on similar solar cells and the voltage drop was measured. As a result, Hollick and O’Brien decided they had a “calibration” that could convert the voltage of the solar cells on the moon into the thickness of dust that accumulated there. They recently published the results of their analysis in the journal Space Weather:1

…this provides the first direct measured long-term net accretion of dust with an upper limit of order 100 µg cm−2 yr−1, equivalent to a layer 1 mm thick in 1000 years, but it may be significantly less.

That is an incredibly fast accumulation rate! After all, if the moon really is about 4.5 billion years old and this rate of accumulation is anything close to representative of what has been going on during that time, the moon should have about thousands of meters of dust on it! Now obviously, this is an incredibly unrealistic calculation. The authors themselves say the rate of accumulation may be significantly less, and meteor strikes can get rid of dust that is already accumulated on the moon. Also, we might be in a particularly “dusty” phase of history. Perhaps this measurement is not indicative of what has happened through most of the moon’s past. Nevertheless, it is hard to imagine how this estimate can be made consistent with an ancient moon without a lot of special pleading.

This, of course, is why some scientists are saying Hollick and O’Brien can’t be correct. Science News quotes Dr. Lawrence Taylor as saying:2

It’s just too much dust…Nobody will believe it.

He thinks the estimate is flawed because the fake moon dust isn’t a good mimic of real moon dust. Of course, Taylor could be right. It’s not clear how well an experiment done here on earth with human-made “dust” can adequately model what is happening on the moon with real moon dust.

So should creationists start using the moon dust argument again? Certainly not! While this is probably the best estimate of moon dust accumulation yet, it still has its flaws. Nevertheless, I plan to keep my eye on what happens next in this interesting saga!

REFERENCES

1. Monique Hollick and Brian J. O’Brien, “Lunar weather measurements at three Apollo sites 1969–1976,” Space Weather 11(11):651–660, 2013
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2. Meghan Rosen, “Moon Dust Gathers Surprisingly Fast,” Science News, January 11, 2014, p. 6
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Comments

8 Responses to “Will This Bring Back the Moon Dust Argument?”
  1. Alex says:

    Hi Dr. Wile! I’m from Brazil and I’d like express my great admiration for you! I’ve been following your blog for some years now and I’ve seen your admirable patience and commitment to science and the Christian faith (I’m a Christian myself). It’s good to know that you follow the evidence wherever it leads instead of forcing something just so that it corroborate with a certain view.

    I’m not a great reader overall, but I love reading your posts! It has, among other things, strengthened my faith. Keep up this wonderful work!

  2. Jacob says:

    Wow, that’s an interesting study. I’m curious if this will actually bring about a legitimacy to the moon dust argument. Dr. Wile, do you have any idea what substances they used to create the fake dust?

  3. James says:

    I definitely agree that these findings don’t give a strong argument. However, I feel like even if the experimental mock-up was accurate in determining how much less voltage would be produced, it still wouldn’t be a strong determinate in dust accumulation.

    I think simply the voltage alone doesn’t tell us enough. I think there’s many other factors that need to be taken into account. One example is radiation damage, i feel like the solar panel would be subject to a lot of cosmic radiation, which in turn would damage the solar panel making it produce less voltage. Since we don’t know how a solar panel operates long-term on the moon we can only guess how much this would affect it.

    Another possible source of error is the sun itself. If the voltage differences are small then even a small power output difference from the sun might offset the result. Of course I’m no physicist (yet) on the energy of the sun, so it could be insignificant but it’s still something that needs to be addressed.
    http://www.space.com/23934-weak-solar-cycle-space-weather.html

  4. jlwile says:

    Thank you so much, Alex!

  5. jlwile says:

    Jacob, this study by itself will not bring legitimacy to the moon dust argument. The measurement just isn’t solid enough. However, it is a step in that direction. In answer to your question, the scientists actually used a synthetic substance, because moon dust is very fine but at the same time very sharp. In the Science News article, O’Brien says, “Think of shards of a broken bottle.” That’s hard to simulate with dust here on earth, so they used a synthetic material that mimicked the features of moon dust.

  6. jlwile says:

    You bring up some good points, James. I know the sun issue is supposedly taken into account. That’s why there are thermometers in the device. The thermometers tell you how bright the sun is, and there is a pretty standard response curve that can be used to deal with that. However, the radiation damage is definitely an issue. Their argument is that radiation damage takes a much longer time to become significant, based on their experience with other solar cells in robotic spacecraft and space telescopes. However, it’s not clear exactly how well that applies to solar cells on the moon.

  7. Jacob says:

    Thank you for answering my question, Dr Wile. But I’m afraid you misunderstood what I meant about the moon dust argument; forgive my wording. I can see that this study in of itself could not possibly bring any legitimate meaning to the moon dust argument – there isn’t enough solid evidence to even begin to think such a thing. I simply meant that I was curious if further studies WOULD bring about such validity.

  8. jlwile says:

    I understand, Jacob. I think further studies would need to reveal two things to make the argument useful again. First, they would have to show that this estimate is reasonable. Second, they would have to provide evidence that there is nothing unusual about this rate of accumulation. That way, it would make sense to think that it could be extended thousands of years back into the moon’s past.

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