A World With no Moon

May 24, 2005 11:32 AM

After a long and ridiculously heated quasi-scientific discussion last night, I absolutely must know: what would happen to life on earth if the moon suddenly disappeared? I say the results would be disastrous, but my friend doesn't think it would matter much. I'd be interested to know who is more accurate in her assessment and the specific problems associated with a moonless earth.
posted by TheGoldenOne to Science & Nature (43 answers total)

Google Answers question about same.
posted by alana at 11:37 AM on May 24, 2005

what were you thinking of that might be disasterous?
i can imagine that a lack of tides would destroy some ecological habitats, but i have no idea how serious an effect that would have on the whole biosphere. and i can't for the moment think of how else it would affect us.
posted by andrew cooke at 11:38 AM on May 24, 2005

How would this affect women and their cycles.. Are they not related?
posted by eas98 at 11:41 AM on May 24, 2005

Even Uncle Cecil isn't too sure. He seems to lean toward the idea that you're wrong.
posted by IshmaelGraves at 11:43 AM on May 24, 2005

"With out the Moon... Uh.. We'd all be very sad."

This is a quote by my History of Jerusalem prof from years ago. Imagine it being spoken in a deep, Kissenger-esq German/Jewish accent for no apparent reason at all. He just burst out with it during a lecture, then made a note in his paper. Everytime I hear this question (there was a Discovery special on it a few years back hosted by Captain Sisko, I think) I get a serious case of the chuckles.
posted by robocop is bleeding at 11:49 AM on May 24, 2005

I didn't read the links yet but it's the loss of the gravitational effects that would be missed. I don't know that they have any effects on menstruation but andrew cooke's on the money for known results. I wonder if there are other subtle effects whose nature has not been elucidated because testing is impossible. But that's just musing (for eg. I always kind of thought that there might be minor effects on neurobiochemical processes which would explain full moon craziness -- if anyone accepts that phenomenon actually exists).
posted by peacay at 11:50 AM on May 24, 2005

I'd think the loss of (most of the) tides would be devastating to many forms of life, not to mention all the nocturnal beasties that need the moonlight to survive. And we're not just talking about tide pool animals, it's all the circulation of water that carries prey, dictates migration, heats and cools the atmosphere... In addition, I don't think most people realize that the moon affects all life on the planet, however subtly.

Also, the Earth's orbit may change without the stabilizing (?) weight of the moon, and who knows what effect that might have on our climate...

On preview, eas98 is right: the moon greatly influences women's menstrual cycles.
posted by Specklet at 11:51 AM on May 24, 2005

There's a very good book about exactly this subject. The really key question is: when do you take the moon go away? If it's tomorrow, we'll survive. The major effect is that we'll have much lower tides---there will still be solar tides. On the other hand, if the moon never existed, life might never have started. Earth might be a slightly colder Venus, with about a 6.5hr day. The moon has greatly increased our day length. Anyway, I highly recommend the book.
posted by bonehead at 11:53 AM on May 24, 2005

In addition to the effects listed in the links above, I've read (though can't substantiate) that the moon's orbit also has a stabising effect on earth's polar angle, therefore keeping stable the magnitude of seasonal change. That sort of thing doesn't change overnight, but could apparently potentially change faster than species can typically adapt, causing problems and die-offs and the like in those biomes that are particularly seasonally dependant.

I'd guess that the results would be disasterous in a mellow, treacle-like kind of way. Meaning, it would make some fundamental changes that would have massive amounts of repercussions in all sorts of little and unexpected ways (though many only over long periods of time), but it wouldn't be anything to head for the hills over, unless chunks of moon-rock were raining down :-)
posted by -harlequin- at 11:56 AM on May 24, 2005

I seem to recall that a small but significant amount of insolation comes via reflection from the moon, so there may be some minor effect there. The new tidal stream energy technologies are likely to be screwed, though I think the sun would still have some effect on tides. Surfing would be right out.
posted by biffa at 12:06 PM on May 24, 2005

Well, according to a documentary on TLC/Discovery that I saw a couple days ago, the answer is: we're all screwed.

They argued (semi-extensively) that the axis of rotation for Earth would get all screwy. Right now our axial tilt scribes a circle as it wobbles -- according to the film, without the moon it would scribe a large ellipse. Which sounds pretty dull, until you realize this would mean that the arctic would turn into a flaming hot desert (and back again, while the equator freezes, etc.) pretty regularly.

If the film was correct, then you could expect the majority of species on Earth to die out, along with most of the people. Not all life, mind you, just a lot of it.
posted by aramaic at 12:07 PM on May 24, 2005

eas98, Specklet: It may well be the case that the similarity between the period of the human menstrual cycle and the moon's cycle of phases is coincidence.
posted by RichardP at 12:10 PM on May 24, 2005

Anecdotal, I know, but it never felt like a coincidence to me - when I wasn't on the Pill I felt my period most definitely changed and coincided with the moon cycles.
posted by agregoli at 12:24 PM on May 24, 2005

I think the "meteor shield" idea is ridiculous. The reason the moon is cratered is because it has no atmosphere. Earth's atmosphere is what protects it, not the moon. (As someone on the Google page pointed out, the moon only blocks about 5 millionths of Earth's view of space.)

The effects on life could be pretty substantial, because of the lack of light at night and the slowing of the tides. If the slowing of the tides manages to stop the circulation of the oceans, we could see some of the northern regions of the world getting much colder, too. However, I'm of the opinion, as in Jurassic Park, that "life finds a way". Some species might not adapt, but I don't think it would be the end of life on our planet.

I feel strangely compelled to point out that the picture in this Straight Dope article has a guy doing the goatse.
posted by knave at 12:26 PM on May 24, 2005

haha, i thought ease98 was referring to the recent Schwarzenegger hoax
posted by yeahyeahyeahwhoo at 12:30 PM on May 24, 2005

eas98, Specklet: It may well be the case that the similarity between the period of the human menstrual cycle and the moon's cycle of phases is coincidence.

I don't think that much of anything to do with the human body and its functions is based on coincidence, but I do appreciate the link.
posted by eas98 at 12:30 PM on May 24, 2005

knave:
It doesn't seem ridiculous to me. The gravity effects on an incoming rock from a binary planet sysem like ours would seem to be pretty complex.

5 millionths is a completely irrelevant figure - any rock other than a comet (and even most comets) will come in along roughly the same orbital plane that is occupied by the moon (the solar system, including the asteroid belt, is largely flat), and as the moon rotates rapidly (28 days), and is lighter than the earth therefore has the wider orbit, it sweeps it's gravity-well through that plane in what would seem to be a reasonable shield. If it disrupted one in five incoming rocks, I'd call that extremely useful.
posted by -harlequin- at 12:47 PM on May 24, 2005

To continue the derail, I couldn't get that link to work, RichardP, so I'm not sure what argument it contains. But. You're going to have a hard time convincing me (and eas98, it would seem) that such an important cycle mimics moon's cycle by coincidence.

Did you know that a woman (not on the pill) generally ovulates during the full moon and bleeds in the dark? Did you know that you can regulate a woman's cycle by having her sleep with a soft light on for three or four days a month when the moon is at it's fullest?

Doesn't it also make sense that agriculturists, from time immemorial, plant seed in the fertile full of the moon?
posted by Specklet at 12:49 PM on May 24, 2005

Um, the only way gravitational wells affect menstrual cycles is through making the blood drip down. It is a reproductive adaptation that means monkeys and people don't go into heat and can get pregnant pretty much any time. Maybe it's just me, but I'm more inclined to believe in biological, evolutionary reasons than magic moon fairies that granted apes the ability to bleed every month. And yeah, it isn't surprising that agriculturists started planting seed during the full moon once they figured out the coincidence between its cycle and menstruation and fertility. People take coincidences in natural phenomena and ascribe a religious meaning to it all the time. It doesn't prove anything.

Personally, I haven't had that magical moon-ovulation experience, and my only experience with the pill was for six months five years ago. So take it as you will.

As for how the moon's disappearence would affect the Earth, you're talking about weaker tides and a more wobbly rotation axis, the latter probably resulting in greater climate instability.
posted by Anonymous at 1:05 PM on May 24, 2005

I wrote a story about just this very then when I was like 12. We blew the moon up to prevent the Russians from fleeing there.

I will confess that my ideas re: the effects of this were probably not in any way scientifically sound.
posted by xmutex at 1:07 PM on May 24, 2005

Sorry about the broken link Specklet, somehow I placed an extraneous apostrophe at the end of the link. This is the correct link.

With regards to your questions, I am afraid I lack an informed opinion. I posted the link because IshmaelGraves mentioned Cecil Adams' article "I plan to destroy the moon. What effect would this have on the earth?" and I figured AskMe might also be interested in his article "What's the link between the moon and menstruation?"
posted by RichardP at 1:18 PM on May 24, 2005

I'd tend to side with Cecil here: if you're going to convince me that menses and the moon are related in any sense other than etymology, you're going to have to explain why many, many other species of animals have cycles that *aren't* around 29 days long.
posted by Johnny Assay at 1:26 PM on May 24, 2005

schroedinger, I think you're misunderstanding me. No one ever said anything about the spiritual implications of the moon cycle or gravity, for god's sake. It's the light of the moon that regulates a woman's cycle, not moon fairies or gravity.

Your point about agriculturists is a valid one, but also proves my point: if most women ovulate during the full moon, how can it be by chance? Women's cycles are an average of 29.5 (actually not 28) days, which is the exact length of a moon cycle. The majority of women (away from artificial light and artificial hormones) ovulate on the full moon. Too much for me to dismiss it as coincidence. /derail

On preview: Johnny Assay, I think it's because most animals aren't large primates with a similar gestation period.
posted by Specklet at 1:31 PM on May 24, 2005

Estrous cycles of other mammals:

Cow - 21 days
Elephant - 16 weeks
Goat - 21 days
Rodents - 4–6 days

Does the moon just not love these lesser creatures enough to let them in on their secret cycle society?
posted by celibate_life at 1:38 PM on May 24, 2005

First off, how do we know most women ovulate during a full moon? I don't, and while I hardly constitute a valid sample size I'd like to see the studies that use one. I dunno how it couldn't be chance, either. Like I said, there's plenty of natural phenomena that occur by chance and people have ascribed significance to because they didn't think coincidence could be coincidence.

And as for being a large enough mammal, why would size and being a primate have anything to do with it? Other animals can see moonlight just as well as primates can. And even if you want to ignore estrous cycles and focus on strict menstrual cycles, why do great apes vary in menstrual cycle length?
posted by Anonymous at 2:51 PM on May 24, 2005

It's the light of the moon that regulates a woman's cycle, not moon fairies or gravity.

I would imagine that there is an equal amount of evidence that moonlight regulates human female's menstrual cycle as gravity or even moon fairies. At least no more evidence has been presented here.

Johnny Assay: you're going to have to explain why many, many other species of animals have cycles that *aren't* around 29 days long.

Specklet: I think it's because most animals aren't large primates with a similar gestation period.

Uh, that's not an explanation at all.
posted by grouse at 3:01 PM on May 24, 2005

Back on topic: I think it would depend greatly on how it is exactly that the moon disappeared.
posted by grouse at 3:04 PM on May 24, 2005

I too would like to know who these women are who ovulate during the full moon. Links, studies, citations? This assertation would imply that most women would have identical cycles. Having played on sports teams my whole life, I can tell you that maybe 3 or 4 of us at a time, out of 15-25 girls and women, would be cycling at the same time.
posted by peep at 3:05 PM on May 24, 2005

It is possible that woman's ovulation evolved to be in sync with the moon so that women would be able to predict when they ovulate. Lacking any estrus, homo sapien females that could figure it out might find such information very useful. Like all evolutionary "just so" stories, this one is purely speculative. It is, however, convincingly argued for in this book .

In any event, the moon has no effect on a woman's ovulation, any more than a calender has an effect on the passing of seasons.

Specklet, you don't know what you're talking about, and you're confusing correlation with causation.
posted by yesno at 3:13 PM on May 24, 2005

I alluded to a point that I ought to clarify. Most primates have visible estrus, and go into heat. Human females, for whatever reason, do not. We are the only primate species where the female wastes time (as it were) coupling when there is no hope of pregnancy.
posted by yesno at 3:19 PM on May 24, 2005

But human females are continually fertile. Yes, there are times of the month where they're less fertile than others, but that only results in a decreased probability of pregnancy rather than an elimination of possibility.

That's why efforts to use "natural" methods of birth control (timing when one has sex to line up with the point in the menstrual cycle when the woman supposedly won't get pregnant) are full of bunk. Even a menstruating woman can get pregnant.
posted by Anonymous at 3:59 PM on May 24, 2005

Clearly, with the aid of moonlight, cavemen could catch women on a friday night, and have their wicked way, while if it was dark, the woman most likely escaped, thus those who were fertile at the wrong times were less likely to reproduce.

/not helping
posted by -harlequin- at 4:44 PM on May 24, 2005

Hmm. I can't find any studies of full moon/ovulation correlation that haven't been done on women who aren't regularly exposed to artificial light. I ovulate with the moon (even if my cycle gets off due to stress, it will adjust over a couple months until I'm "back on schedule"), but I'm exposed to artificial light regularly. The women I've known who had no electricity all ovulated in the full of the moon, and there are many historical references to this, but I can't find anything that talks about women today. There are many fish and types of coral, however, whose spawning is triggered by moonlight. So perhaps my response to the moon is purely psychosomatic.

We are the only primate species where the female wastes time (as it were) coupling when there is no hope of pregnancy.

This is most certainly not true! Many mammals have sex for fun, including dolphins. Ever heard of the sexual proclivities of bonobos?

That's why efforts to use "natural" methods of birth control (timing when one has sex to line up with the point in the menstrual cycle when the woman supposedly won't get pregnant) are full of bunk. Even a menstruating woman can get pregnant.

Is is true that a woman can ovulate anytime, including during menstruation, but most women ovulate once a month, on or around the 14th day in their cycle. While I would never use the basal method of birth control alone, I know exactly when I ovulate. Although natural methods of birth control are not as failsafe as others, they are not "bunk".
posted by Specklet at 5:09 PM on May 24, 2005

TheGoldenOne, sorry I was so off topic!
posted by Specklet at 5:10 PM on May 24, 2005

Love. This. Derail.

If ovulation is (even slightly) tied to the full moon, then shouldn't birth rates spike every 29 days? Even accounting for early or late births, the global average should show an increase that corolates to the moon. Me, I can set my watch to my wife's cycle -- every fourth Sunday night, 9 PM. Hasn't changed in 5 years, no pill. Last time, just two days ago. On the full moon.

Look, my anecdotal evidence proves I'm right!
posted by incessant at 5:25 PM on May 24, 2005

These dark nights will be hard on nocturnal hunters. I seem to recall that a variety of creatures synch up their behavior to match the moon. If the moon goes, they'll have problems, no?
posted by Ken McE at 6:03 PM on May 24, 2005

I think it would depend greatly on how it is exactly that the moon disappeared.

The moon did explode five(ish) years ago (on September 15th, if I recall correctly), but the light just hasn't reached earth yet. And have we noticed? HA!
posted by bonehead at 6:08 PM on May 24, 2005

Here is the deal ,the sun rotates on it's axis once every 26 days ,the earth is also orbiting the sun, relative to us the sun takes 28 days. the moon is following the suns lead so it just might be that the menses is governed by that ole rascal Mr.Sun!
posted by hortense at 7:59 PM on May 24, 2005

I hate to throw another log onto the fire, especially since

a. I am male and
b. I can't cite the original source.

But, I once read about a study that was exploring the link between exposure to artificial light and the age which a girl gets her first period. It noted that the age has been steadily decreasing as exposure to artificial light has been increasing. Except for girls who are blind, who have not experienced a decrease in age of first period.

The study was cited by a group looking at the negative aspects of light pollution (they were astronomers) so it's interesting that this derail came up in this context. (They said nothing about whether menstral cycles were connected to moon phases.)
posted by achmorrison at 12:34 AM on May 25, 2005

It noted that the age has been steadily decreasing as exposure to artificial light has been increasing.

Again, confusing correlation with causation. Age of menarche has been steadily decreasing as a number of other factors have changed—for example, the onset of rock and hip-hop music.

Except for girls who are blind, who have not experienced a decrease in age of first period.

Interesting. I'd love to see this study.
posted by grouse at 12:44 AM on May 25, 2005

grouse:

It doesn't sound like anyone is confusing correlation with causation (with the possible exception of the people trying to (ab)use the study to oppose light pollution, and even then I imagine they're not making that assumption). As described by archmorrison, it's a study noting that one group exhibits a different developmentaly behaviour from a very similar group, and that in addition to one of the primary differences between those groups being different experience of light, the changes in expience of light also correlates with the unexplained changes in the group most affected by it, thus suggesting that the correlation may be significant and warrents further investigation.
posted by -harlequin- at 7:07 AM on May 25, 2005

-harlequin-, that is exactly what I was trying to say. :)

This article is the closest I could find to what I first read. I think it is the New Scientist article they refer to that I originally read.
posted by achmorrison at 3:23 PM on May 26, 2005

Further reading leads me to believe that the better conclusion is that more light (at least artificial light) leads to less melatonin. Melatonin in children is tied to the onset of puberty (from what I've read, I am a physicist, so don't shoot me).

It's hard to speculate about the effect the full moon might have on the average person's melatonin level. It would be interesting to see if it is even possible to evaluate that question...
posted by achmorrison at 3:29 PM on May 26, 2005