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Creation 40(4):53–55, October 2018

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The mystery of the moon

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Evolutionists claim that our moon was formed by natural processes without the need for a creator. This view, however, is not supported by science, as all the explanations they propose have major problems.

nebular-hypothesis
Fig. 1. The nebular hypothesis for the formation of the solar system provides the basis for one theory of lunar origins (see text).

Explanation 1: from dust

Evolutionists say that our sun and its orbiting planets (i.e. our ‘solar system’) arose from a rotating gas/dust cloud approximately 4.5 billion years ago. This is known as the ‘nebular hypothesis’, from Latin, nebula meaning ‘cloud’ (see fig. 1). Some have suggested that the moon simply formed at the same time and sufficiently close to the earth to end up in orbit around it. This is known as the ‘condensation theory’. Just as a water droplet condenses from steam as it cools, so the moon is said to have ‘condensed’ from dust as gravity pulled tiny dust particles together into a big lump.

If this explanation were correct, however, we would expect the moon to be akin to a mini Earth, being made up of essentially the same materials. The moon, however, is significantly less dense than the earth, and hence must be made up of different materials. Scientists believe that the primary difference lies in the amount of iron in their cores (see fig. 2).

NASA/MSFC/Renee Weber
13199-lunar-core
Srimadhav, from USGS via Wikimedia


13199-earth-cutaway
Fig. 2. Left: The moon’s likely interior. Right: A partial section through the earth showing the core, mantle and crust. The core is made up mainly of iron. If the moon formed according to the ‘condensation theory’, we would expect it to have a significantly larger iron core than it does.

Explanation 2: a ‘spin-off’

Another suggestion is that an originally molten earth spun so fast that part of it flew off and became the moon (fig. 3). This is known as the ‘fission theory’, from Latin, fissio meaning ‘splitting’, proposed by George Darwin, son of Charles.

Calculations, however, indicate that the earth’s rotational speed would never have been great enough for this to happen—see box p. 55. Another problem is the marked differences between rocks found on the moon and those on the earth. If the moon were once part of the earth, we would expect moon and earth rocks to contain elements in similar amounts; but this is not so. For example, potassium and sodium are found in abundance in Earth’s rocks, but not in those on the moon. Conversely, moon rocks contain significantly more aluminium, calcium and thorium. This is also a problem for the ‘condensation theory’.

Another good reason for rejecting the ‘fission theory’ arises from a consideration of the moon’s orbital path. If the theory were correct, we would expect the moon to orbit around the earth’s equator as shown in fig. 3; but it does not!

fission-theory
Fig. 3. Formation of the moon according to the ‘fission theory’. If this were correct we would expect the moon now to be orbiting around the earth’s equator; but it is not.

Explanation 3: from outer space

Halleys-comet-orbit
Fig. 4. The orbit of Halley’s comet around the sun is highly elliptical. If the moon ‘capture theory’ were correct, then we would expect the moon to follow a similarly elongated orbit around the earth.

Some have argued that the moon must have formed elsewhere and, as it flew through the galaxy, it just happened to pass close enough to the earth to be captured by its gravity. If this were so, then we would expect the moon to follow an elongated orbit around the earth, similar to that of Halley’s comet around the sun (fig. 4). The moon’s orbit, however, is essentially circular; hence the ‘capture theory’ fails.

Explanation 4: a great impact

This view, currently the most popular among evolutionists, holds that a hypothetical planet (called Theia) collided with the earth and the resulting debris formed the moon (fig. 5). This is said to explain the differences between Earth rocks and moon rocks discussed above. The high temperatures generated by the collision would have boiled away volatile elements such as potassium and sodium, but more heat-resistant materials such as aluminium, calcium and thorium would have remained and condensed to form the moon’s crust.1

Here, however, it is the similarities between rocks that cannot be explained. With the impact theory, part of the moon would have formed from the earth and part from the impacting planet. So the chemistry of moon rocks would be expected to be different to that of Earth rocks. While it is true that the moon is deficient in some Earth elements, those that are shared can have very similar properties.

Elements come in different forms, known as ‘isotopes’ and different rocks contain isotopes in different amounts, giving each an ‘isotope signature’. Remarkably, the isotope ratios of oxygen, iron, hydrogen, silica, magnesium, titanium, potassium, tungsten and chromium are almost identical in moon and Earth rocks. At the same time, they are different from other solar system bodies. This is such a problem for the impact theory that, according to some researchers, it is now in crisis.2,3 These near-identical isotope signatures are also a problem for the ‘capture theory’.

Theia
Fig. 5. According to the impact theory, the moon formed as a result of a collision between an imagined planet called Theia and the earth. If this were correct, we would not expect isotope signatures in moon and earth rocks to be virtually identical.

Another headache for the impact theory is the growing evidence of significant amounts of water in the moon’s interior. It would be expected that the heat from the impact would have caused this to evaporate.4

Given these difficulties for evolutionists, it is hardly surprising that a recent paper, co-written by planetary scientist Professor Oded Aharonson, began with the admission, “The moon’s origin remains enigmatic.” 5 

The real explanation

Of course, the moon is no mystery to those who believe the Bible. According to the book of Genesis, this heavenly body was specially created by God on Day 4 of Creation Week:

And God made the two great lights—the greater light to rule the day and the lesser light to rule the night—and the stars. And God set them in the expanse of the heavens to give light on the earth, to rule over the day and over the night, and to separate the light from the darkness. And God saw that it was good (Genesis 1:16–19).

Semi-technical

The earth and moon, and angular momentum

All moving objects have ‘momentum’, requiring some degree of effort to stop them. The faster they’re moving or the more massive they are, the greater is their momentum. Objects moving in a straight line are said to have ‘linear momentum’; spinning objects, or those in orbit, are said to have ‘angular momentum’.

It is possible to calculate the total angular momentum of the earth together with its moon, and any theory of moon formation must be able to account for this. Here, the ‘condensation theory’ fails because, when compared with other planets in our solar system, the Earth/moon system has too much angular momentum. The ‘fission theory’ fails because it has too little angular momentum: in order to fling material off to form the moon, the earth must have been spinning very fast.

The ‘impact theory’ also fails because impact scenarios which give rise to a moon comprised mainly of earth material (and therefore moon rocks with similar isotope signatures) result in too much angular momentum.1

References and notes

  1. Rufu, R., Aharonson, O. and Perets, H.G., A multiple-impact origin for the Moon, Nat. Geosci. 10:89–94, 2017 | doi:10.1038/NGEO2866.

References and notes

  1. Wlasuk, P.T., Observing the Moon, Springer-Verlag, London, p. 32, 2000. Return to text.
  2. Elkins-Tanton, L.T., Occam’s origin of the Moon, Nat. Geosci. 6:996–998, 2013 | doi:10.1038/ngeo2026. Return to text.
  3. Oard, M.J., Confusion over moon origins: Naturalistic origin of the moon comes under hard times, J. Creation 30(1):14–15 April 2016. Return to text.
  4. Moon has a water-rich interior, sciencedaily.com, July 2017. Return to text.
  5. Rufu, R., Aharonson, O. and Perets, H.G., A multiple-impact origin for the Moon, Nat. Geosci. 10:89–94, 2017 | doi:10.1038/NGEO2866. Return to text.

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