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Moon


Here are some spurious arguments, often used by Young Earth Creationists, about the Moon


The Moon Dust Argument

The Receding Moon

Effects of Voluatility on Rubidium-Strontium Dating

Moon Rock Viscosity


The Moon Dust Argument

The basic theory goes something like:

There is a constant influx of meteoric dust to the Moon. If the Moon is 4.6 billion years old, this constant influx should produce a layer of moon dust "X" feet thick. Since the actual Moon dust is only a few centimetres thick, the Moon cannot be billions of years old and thus the Earth and the Moon must be recent.

In order to calculate the X factor, young Earth creationist almost inevitably quote Patterson (1960) and use a figure of 14 million tons of meteoric dust per year (for example, Morris 1974, Morris & Parker 1982). The actual figures are (from Morris 1974):

    Influx: 14 million tons/yr
    Density: 140lb/ft^3
    Area of Earth: 5.5 x 10^15 ft^2
    Age of Earth: 5 billion years
    Layer: 182 ft (50.48 mtrs)

The figure for the layer is used as an approximate figure for the Moon.

Now whilst this may seem straightforward, as is usual with young Earth creationist claims, it isn't.

In his 1960 article in Scientific American, Patterson described how he collected dust from the top of Mauna Loa, on Hawaii, and from the top of Haleakala, on the island of Maui. He then goes on to say,

" It was nevertheless apparent that the dust collected in the filters would come from terrestrial sources. To distinguish the portion contributed from space, my scheme was to rely upon the high nickel-content of meteorites. Analysis of large meteorites had shown that the 'irons' characteristically contain 7.5% nickel and that even the 'stones' have 1%. According to Fletcher G. Watson of Harvard University, the average nickel-content of all kinds is 2.0 to 2.8%. Since nickel is a rare element in terrestrial dust, it was reasonable to assume that any nickel found in dust samples came from meteoric sources. Taking 2.5% as a fair average of Watson's estimates, I needed only to multiply the weight of the nickel by 40 to find the total weight of the dust from meteoric sources." (P. 132)

Patterson's implicit assumption here was that all the nickel measured came from meteoric dust. As will be shown, this was incorrect. He continues,

"Most of the samples contained small but measurable quantities of nickel along with a large amount of iron. The average for 30 filters was 14.3 micrograms of nickel from each 1,000 cubic metres of air. This would mean that each 1,000 cubic feet of air contains 0.6 milligrams of meteoric dust. If meteoric dust descends at the same rate as the dust created by the explosion of the Indonesian volcano Krakatoa in 1883, then my data indicate that the amount of meteoric dust landing on the earth every year is 14 million tons. From the observed frequency of meteors and from other data, Watson calculates the total weight of meteoric matter reaching the Earth to be between 0.365 and 3.65 million tons a year. His higher estimate is thus about a fourth of my estimate, based on the Hawaiian studies. to be on the safe side, especially in view of the uncertainty as to how long it takes meteoric dust to descend, I am inclined to find 5 million tons per year plausable." (p. 132).

Patterson was well aware that the nickel content in dust was not entirely of meteoric origin, for as early as 1951 he wrote, concerning the nickel content of central Pacific sediments,

"Assuming that the whole [original emphasis] of this nickel is of cosmic origin and that the distribution is uniform within the time-span involved, the total accumulation of the element to the whole of the surface of our planet becomes 40x10^12 g per 1000 years or 40,000 tons per annum. Ascribing an average nickel content of 2% to the cosmic dust, the latter figure has to be multiplied by 50 in order to reach the total contribution of extraterrestrial matter to the Earth in the course of one year which gives 2 million tons*". (Patterson & Rotschi 1951, p. 88-89)

The"*" refers to a footnote at the bottom of page 89 which says:

"*It has been assumed in these calculations the all [original emphasis] the nickel found is of cosmic origin in order to obtain a maximum value for the accumulation of the material required. Obviously this assumption cannot be correct for a considerable part of the nickel is probably of terrestrial origin. . . . This would reduce the total quantity of such material carried to the Earth from 2 million to 1.4 million tons annually."

Patterson's original assumption that all nickel was of extraterrestrial origin was incorrect, Patterson knew this. That is why in his paper he rounded down the calculated influx rate fron an original value of 14 million tones per year to 5 million tones per year, but he was still guessing. As early as 1955 the link between influx levels and nickel abundance had been challenged. Leavasta and Mellis (1955) has taken some deep sea core material from which Patterson had previously measured nickel abundance and counted magnetic spherule abundance. Since the magnetic spherules are of extraterrestrial origin, they gave a far more accurate measure of influx. If the nickel abundance was totally due to extraterrestrial influx as well, the amounts of both through the core should correlate. Leavasta and Mellis found no correlation between spherule abundance and nickel abundance. Thus the abundance of nickel was being augmented from terrestrial sources. Patterson knew that the nickel values were 'contaminated' by terrestrial imput and was only looking for a ballpark figure. Since the amount of contamination was unknown he ignored it to come up with a theoretical maximum value, not an accurate one. However since at that stage it was all there was to work with, it was a worthwhile endevour.

Shedlovsky and Paisley (1966) obtained an influx rate of <100,000 tones per year by measuring the concentration of iron in the stratosphere.

Barker and Anders (1968) measured iridium and osmium in deep sea sediments. These elements are orders of magnitude less abundant in the earth's crust that nickel and so the terrestrial contamination problem would be correspondingly less. They came up with a value of between 100,000 tones and 8000 tones per year for the dust influx. This confirmed Leavasta and Mellis's work in that not only was the spherule data indicating a much lower influx, but the nickel values were substantially contaminated by terrestrial sources. It had to be, if the 14 million tons was correct, Antarctica would be dark with accumulated dust!

Since the late sixties much better and more accurate figures are available thanks to direct measurements in space. These show the influx rate to be about 22,000 tons per year (Dohnanyi 1972). More recent measurement put the figure even lower, at between 11,000 - 18,000 tons per year (Hughes 1975).

Now, using a figure of 22,000 tons per year, realizing that the Moon's gravity and area is less than the Earth's, we get (From Dalrymple 1984):

    Influx: 22,000 tons/yr
    Density: 140lb/ft^3
    Area ofMoon: 1.63x 10^15 ft^2
    Age of Moon: 4.6 billion years
    Layer: 1.6 inches (4.1 cm)

Claims that the lack of Moon dust imply a recent Earth are bogus. The Moon dust arguement has even been refuted by the ICR.


References

Barker, J.L. & Anders. E. (1968) Accretion rate of cosmic matter from iridium and osmium contents of deep sea sediments. Geochim. et Cosmochim. Acta, 32: 627-645.

Dalrymple, G.B. (1984) How old is the Earth? A reply to "scientific" creationism. Proceedings, 63rd Annual Meeting of the Pacific devision, American Association for the Advancement of Science, 1(2) 66-131.

Dohnanyi, J.S. (1972) Interplanetary objects in review: statistics of their masses and dynamics. Icarus, 17: 1-48.

Hughes, D.W. (1975) Cosmic dust influx to the Earth. Space Research XV: 531-539.

Laevasta, T. & Mellis, O. (1955) Transactions of the American Geophysical Union, 36: 385.

Morris, H.M. (1974) Scientific creationism (Public School Edition). Creation-Life Publ., San diego, California. 217 pp.

Morris, H.M. & Parker, G.E. (1982) What is creation science? Creation-Life Publ., San diego, California. 306 pp.

Patterson, H. (1960) Cosmic spherules and meteoric dust. Scientific American, 202: 123-132.

Patterson, H. & Rotchi, H. (1951) The nickel content of deep-sea deposits. Geochimica et Cosmochimica Acta, 2: 81-90.

Shedlovsky, J.P. & Paisley, S. (1966) On the meteoric component of stratospheric aerosols. Tellus, 18: 499-503.


The Receding Moon

A common argument is that since the Moon is receding from the Earth at a rate approaching 6 inches per year, extrapolating backwards indicates that the Moon would have been inside the Earths Roche limit (and thus destroyed) about 2 billion years ago. Thus the Earth-Moon system cannot have been in existence 2 billion years ago. This is wrong because a uniformitarian application of the recession rate is incorrect. The rate at which the Moon recedes is connected with the tides on the Earth. The gravitations interaction of the Moon with the tides causes the Earths rotation to slow. To conserve the energy of the Earth-Moon system, the excess is transfered to the Moon, pushing it into a higher orbit. The current rate is considered to be high because the spin of the Moon and the tides are thought to be nearly synchronous. In the past, the movement of the continents interrupted this, leading to a much lower rate of recession. Evidence from rythmic tidelites and fossil coral 'clocks' support the view that the number of days in a year was higher in thegeological past - in line with a faster spinning Earth then.


Effects of Voluatility on Rubidium-Strontium Dating

Wright (1976) states:

"Some estimates of the age of Moon-rock specimens have been based on the ratio between rubidium and strontium. it should be pointed out that under the conditions of temperature and pressure known to exist on the Moon, unequal migration of the two elements must result.

Examination of the vapour-pressure curves for the elements shows that pressure of rubidium is more than 10^7 and up to 10^8 times that of strontium at a temperature of the lumar surface reached during the long lunar day (+150 C), and the vapor of rubidium at this temperature reaches a value of 0.01 Torr; the inevitable result of this would be for a substantial amount of rubidium to vapouize and migrate freely. Even if the rubidium were to be chemically combined in the form of less volatile compounds, the constant bombardment of the surface by hydrogen ions in the solar wind would reduce the compounds to free the metallic rubidium.

[.]

Strontium, having a vapor pressure more than 10 million times lower than that of rubidium, would be less affected by this mechanism. The result might be that the estimate of age based on the ratio of these elements would be strongly affected by their local origin on the lunar surface. Vapor migration is a mechanism that may cast doubt on the elemental ratio dating, at least when pairs with widely different volatilities are employed."

There are four problems with this.

Firstly, Rubidium-strontium dating is not a process of merely comparing ratios. Dating is done via an isochron method, which is inherently self-testing. Data is plotted on a graph and only if the data plots on a straight line is the age considered valid. Any pertubation of the elements will results in a scatter of data points, which immediately flags the sample as having being adversely affected. If the samples had undergone differential rubidium v. strontium loss, the resultant data points would be widely scattered, making it impossible to accurately date the rock.

Secondly, the vapor-pressure curve really only applies if the samples in question are blocks of pure rubidium and pure strontium, and then it only applies to a micrometric surface layer. In reality, the rubidum and strontium are held in a rigid silicate lattice, which securely binds the elements.

Thirdly, this is a surficial phenomenon. Both in terms of applying to the surface of the Moon and the surface of the rock. Rocks which are covered are not affected, and samples of rocks for dating are taken from the pristine inner part of the rock - the surface layers are ignored.

Fourthly, Rb-Sr dating gives results which are in close agreement with other dating methods for lunar rocks, such as U-Pb and Ar-Ar. If volatility was a problem for Rb-Sr dating, then U-Pb and Ar-Ar dating must also be wrong, but through different mechanisms, mechanisms which although different, nevertherless result in the same answers!


References

Wright, C.R. (1976) Effects of volatility on rubidium-strontium dating. 226-227. In: Velikovsky Reconsidered. Sidgwick & Jackson, London.


Moon Rock Viscosity

An argument for a young Moon based on the viscosity of lunar rocks goes something like this:

We all know that liquids flow, right? Glass does this too - old windows are thicker at the bottom than the top. Well, given enough time so do solids. Granite is one of the hardest and slowest flowing materials on earth, but it's flow rate has been measured by scientists. This can also be observed looking at tombstones and other rock monuments.

Actually, no it can't. I know of no granite tombstone or monument which shows viscous flow unless it has been affected by heat.

Now take a look at the moon for eg, it's covered in craters - more so than the earth, but basically the same. The reason earth has less is due to the erosion factors of wind/rain etc. Now, most scientists believe this to have happened to the moon at least 3 billion years ago. Studies have been made on lunar rocks to discover the flow rate...

If the moon was covered in water, the craters would only last a few seconds right? If it were covered in honey, they would last a little longer. Since it is covered with rock, they last a lot longer, but how long depends on the kind of rock and it's viscosity rate or flow.

Lunar rocks are virtually identical to the earth's basalt rock. This proves that the moon's craters can't be more than a few thosand years old!

Excuse me?? Having similar composition doen not "prove" that two things are the same age. It just indicates that the process of formation of the two was probably similar. Lava's erupted in the last few years on Hawaii are "virtually identical" to those which erupted a 100 years ago, does this mean the the 100 year old lava's are actually only a few years old? Also there is a very important difference between Moon basalts and most Earth basalts, namely radiogenic isotope ratios. According to physicists, this indicates that the Moon basalts are considerabley older than virtually all Earth basalts.

The viscosity or flow-rate value used scientists is on the order of a hundred million times too low (the higher the value, the slower the flow rate) for the craters to have lasted 3 or 4 billion years. Even if the lunar surface were made of granite, the viscosity value of that granite would be 10 million times too low to hold the crater shape for 3 billion years. if the lunar surface were made of the same rock as the earth's mantle, the viscosity value would be too low by a factor of 100,000.

There are a whole heap of misconceptions in this argument.

Firstly, whilst the composition of Moon basalts (MB) is similar to Earth basalts (EB), there are other factors to be taken into consideration.

It turns out that Moon basalts in the melt (i.e. molten) have significantly lower viscosities that Earth basalts. This is due, in the main, to low silica levels (43% - EB ave = 50%), high iron (21% - EB ave = 7-10%) and high titanium (11% - EB ave = 1%) (Murase & McBirney 1970), and explains the long distances travelled by lunar lava flows.

However, as solid rock, MB's have higher viscosities than EB's, or even granites.

"Viscosity values as estimated from isostatic processes and from temperature and melting point-depth relations show that the Moon's outer layers are much more viscous than any geological region on earth." (Meissner 1977, p. 463).

The much higher viscosities of lunar rocks as compared with Earth rocks are due mainly to temperature and water content.

Solid rocks are less viscous at higher temperatures. In other words, the higher the temperature, the easier it is to flow. The earth has an average heat flow rate from the surface of approx. 8.4W/cm^2 compared with the Moon's 1.8W/cm^2 (Glass 1982). This means that surficial rocks on the moon are much cooler that those on the Earth, which means that Moon rocks are more viscous than Earth rocks.

Water content (the presence of hydrated minerals) is also important, since rock with higher water contents are less viscous than 'dryer' rocks. Moon rocks contain much less water than Earth rocks and therefore have a higher viscosity.

This, plus the fact the the Moon's gravity is less than Earth's, means that Moon rocks are much more viscous than Earth rocks, thus far more resistant to flow, and so craters survive a lot longer.

Finally, the viscosity of the Earth's mantle material is low because it is under very high temperatures and pressures, plus the rocks are hydrated. The viscosity of mantle material cannot be compared with Surficial Moon rocks which are at considerably lower temperatures and pressures and are not very hydrated.


References

Glass, B. P. (1982) Introduction to Planetary Geology. Cambridge University Press, Cambridge. 469 pp.

Meissner, R. (1977) Lunar viscosity models. Philisophocal Transactions of the Royal Society of London, A 285: 463-467.

Murase, T. & McBirney, A. R. (1970) Viscosity in lunar lavas. Science, 167: 1491-1493.


Last modified: March. 30th. 1998