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Is the Moon Too Close?

by Steven Novella, Jan 24 2011

I was recently asked about the creationist “proof” of a young earth that the moon is too close to the earth. Specifically I was asked to comment on the arguments of Dr. Richard Kent, a UK creationist. On his evolution- debunking site he claims:

Observation demonstrates that the Moon is getting farther from the Earth by two inches every year. This indicates that the Moon used to be closer.

This causes very serious problems to the Evolutionists, because the proximity of the Moon to planet Earth controls the height of the tides.

Kent's arguments are bad, even for a creationist. It made me wonder if UK creationists are not as experienced or sophisticated as their American counterparts. Kent argues that 4 billion years ago the tides would have been so large that life would not have been possible. However, life was restricted to the ocean until about 500 million years ago – it is not clear by large tides would have been a problem for bacteria living in the ocean. In fact, the high tides were perhaps a boon to ocean life as they scoured the land and deposited minerals into the oceans.

Kent also has this gem:

- The magnetic forces of attraction between the Moon and the Earth become very slightly weaker every year, so that, in general, tides become slightly lower on average.

I love it when cranks get basic scientific facts wrong, because it so clearly exposes their intellectual laziness and scientific illiteracy. The tides are caused by the gravitational forces between the earth and moon, not magnetic forces.

But actually I wonder if Kent is one step ahead of his American counterparts, because Kent is not claiming that 4 billion years ago the moon would have been inside the earth or within the Roche limit (which many creationists falsely claim), but perhaps has tried to rescue this failed argument with his point about the tides being too high. That may be giving him too much credit.

The Institute for Creation Research (ICR) gives the more standard earth-moon argument for why the earth cannot be 4.5 billion years old. They write:

The present speed of recession of the moon is known. If one multiplies this recession speed by the presumed evolutionary age, the moon would be much farther away from the earth than it is, even if it had started from the earth. It could not have been receding for anything like the age demanded by the doctrine of evolution. There is as yet no tenable alternative explanation that will yield an evolutionary age of 4 billion years or more for the moon. Here is as simple a proof as science can provide that the moon is not as old as claimed.

Creationists love the evolution knock-out punches – the one argument or line of evidence that all by itself proves evolution is impossible. Of course, if their argument were true it would present a huge, perhaps fatal, problem for evolution. Interestingly they often simultaneously claim that evolution is not falsifiable – and then they try to falsify it. Evolution is falsifiable, and if any of these killer creationist arguments were true, evolution (or at least certain aspects of it) would be falsified. Alas, they are all silly and/or outdated arguments.

That the ICR and countless other creationist sites are still using the earth-moon distance argument to falsify evolution is also very telling. The argument has been destroyed years ago (during the 1980s and in great detail by the 1990s), but the facts do not seem to get in the way of a good creationist argument. The creationist strategy is clear – find some anomaly that scientists have not yet fully explained and then claim that the anomaly proves evolution is false, or the big bang did not occur, or the sun or moon or earth cannot be billions of years old. Anomalies, however, are not good proofs – they just reveal the fact that our knowledge is incomplete. Scientists treat anomalies as opportunities to deepen our understanding, to great success. Creationists see anomalies as propaganda opportunities, and never let go, even when the anomaly is later explained.

In this case the distance of the moon was a genuine anomaly. The basic facts are this – the moon is moving away from the earth due to the transfer of angular momentum from the earth to the moon as a result of the tidal interaction between the two. At present the moon is moving away by about 2.5 cm per year (there is some debate as to this exact figure that I do not want to get into here). The ICR and other creationists assume (usually without expressly stating that assumption)  that the 2.5cm per year figure is constant, and can be extrapolated simply into the past. This turns out to be a false assumption.

The exact manner in which the earth transfers momentum to the moon as a result of the tidal interaction is actually fairly complex. It is affected by the surface features on the earth. Depending upon how you model the earth the calculation can be dramatically different. Initial figures, in fact, produced an age of the earth-moon system that was far too great. But then later revisions came out with an upper limit of 1-2 billion years – short of the needed 4.5 billion years. Creationists latched onto this historical state of the evolution of our understanding of the tidal forces on the earth moon system, because it served their purpose, and then they stopped updating their arguments as the science progressed.

The turning point came with the discovery of plate tectonics – the continents on the earth were not always where they are now. In fact for much of the history of the earth all the land mass was joined in one supercontinent or another. This dramatically affects the calculations for momentum transfer. Modern calculations, with better models of the earth and the earth-moon interaction, now agree with a 4.5 billion year old earth. Anomaly solved. Talk origins has a thorough discussion of the history of this calculation.

This information is now freely available, for more than a decade. The creationist argument was always thin, little more than anomaly hunting and denial. But now it is also outdated. The fact that they do not acknowledge the actual science and they stick to their simplistic and wrong models tells us everything we need to know about the scientific and intellectual integrity of creationism.

24 Responses to “Is the Moon Too Close?”

  1. tells us everything we need to know about the scientific and intellectual integrity of creationism

    Can you tell people about things that don’t exist? Oh yeah, they do it all the time. ;)

  2. Oh we have the full spectrum of creationists over here in the UK too – thanks very much for that.


  3. Okra says:

    No wonder that we can’t fall upward–we’re magnetically bound to the earth! I am so relieved…

    Why don’t they just stick to resolving the contradictions and inaccuracies in the Bible? There’s enough to keep them busy for millennia.

  4. marke says:

    Love their concept of doing the maths once, and if you get the “right” answer, put a full stop and it’s done!

    No concept of examining, debating, recalculating, assessing alternate theories, new discoveries….. creationism is a long way from science.

  5. John Paradox says:

    One inconsistency I see in the ‘ID’ crowd is that they consider the motion of the Moon to be the same rate throughout time (the 2.5 cm), but when they talk about radiation, such as carbon dating, the rate of the change from radioactive element changes, because it doesn’t fit with their 5K years.

  6. EricJ says:

    The tides come in. The tides go out. Explain that, you atheist socialist.

  7. Edgaras says:

    Haha brilliant topic. Creationists – enough said. Agree with 4th comment also.

  8. MadScientist says:

    The creationist argument was never any damned good. Many years ago someone figured out that the moon was receding. They came up with some ideas to test – the early ideas weren’t so refined. As time passed people made better measurements and improved the ideas – they knew the earlier ideas couldn’t be exactly right because some estimates didn’t match up with other available evidence. This is how science normally progresses. The creationists say “hey, scientists admit that Model X doesn’t currently agree exactly with Observation Y – therefore god!” – a claim which of course has absolutely no basis in reality. Where scientists say “we haven’t understood this well enough yet”, the religious try to wedge their god into that place. But since science has made so much progress, the religious have no place to shove their god except up where the sun doesn’t shine.

  9. Ted Judah says:

    Excellent post Steven. As an amateur astronomer who does public outreach I find that there are some interesting “theories” out there.

  10. peter says:

    405,696km is the earth moon distance at apogee.
    Just a short and dirty calc. not taking into account anything like momentum transfer and the initial acceleration after the collision event shows that at 2x1o^9 years and a constant rate of movement away from earth the distance would be only 5×10^4 closer than it is today, which is only about 12% closer than today.
    In precambrian times, about >5×10^8 ago the moon would only have been 15000km closer, about 4%.
    So, what’s with this claim about tides? The difference in distance between the precambrian and today is less than the difference between apogee and perigee -over 40000 km.

  11. Douglas says:

    The Earths relationship with the moon is something that is very convenient, believers might say miraculous. The moons influence on the Earth keeps the mantle motive, keeps the seas dissolving, or absolving gasses as necessary.

    the range of the moon is perfect for comparative size in the sky, The Moon was what invited thought about skeptical space.

    The combination of factors are not out of the range of believers to find those who believe in the miraculous among scientists.

    I’m an atheist, but perhaps sometimes, the miraculous is simply misunderstood by the fundamentalists, while understood by the believing scientists?

    I really wish you guys would stop being jerks sometimes.

  12. Dean M says:

    This evolution-as-house-of-cards mentality is something I don’t understand. I’m currently learning Arabic for fun. (Yes, it’s pathetic. You have your hobbies, I have mine.) My dictionary doesn’t have an Arabic word for peanut butter. Applying the same logic that creationists use to attack anomalies in science, one would have to conclude that Arabic has no word for peanut butter. That’s silly enough. But creationists go further. If I don’t know there is an Arabic word for peanut butter, and if I can’t prove from the available dictionary that there is, that doesn’t just mean there’s no such word: it means the entire Arabic language is a fraud and illusion and does not, in fact, exist.

  13. Kenneth Polit says:

    Scientific and intellectual integrity of creationism? Really? Creationism is anti-science and anti-intellectual. The creationist tries to use science sounding terms and arguments to promote their religion. It doesn’t work because they suck at it. These are “people of faith” who’s faith is so incredibly weak that they can’t tolerate anything that contradicts the literal reading of the bible. Creationists(I call them IDiots) don’t care about facts, hell, they don’t even care about reality.

  14. Think about it, if the moon was made of cheese and the Earth was lactose intolerant, then maybe this explains the gas coming from these creationist assholes?

  15. Adam Onymouse says:

    the creationist stated ” [...]that the Moon is getting farther from the Earth by two inches every year.”, you used 2.5cm/year,
    a quick search yields:
    “Measurements from lunar ranging experiments with laser reflectors left during the Apollo missions have found that the Moon’s distance to the Earth increases by 38 mm per year”

    1 inch = 2.54 cm

    if the creationists use 2 inch that amounts to 5.08 cm or 50.8 mm.
    so using 50.8mm instead of 38mm that is quite some error :)
    but it gets worse if you use this flawed value for further calculations…

    (sources: and…387..700C )

  16. Citizen Wolf says:

    The creationists are missing the point, of course. I mean, is the moon even real? Watch Ali G interview Buzz Aldrin. Hilarious.