# Is lunar effect on humans lunacy?

1. Mar 13, 2012

### mattbatson

I have done some reading, and found articles with little to no references (to scientific journals) that proclaim that although humans are mostly water...the moons gravitational pull has very little, if any, effect on our bodies.
I dont believe that there is more crime during full moon's, for instance...however, there are a couple of studies out there which seem to say that there is a coorelation.

I'm looking for actual scientific evidence that our bodies are not physically affected.

Does anyone know where I should start looking?

thx

2. Mar 13, 2012

### Staff: Mentor

The myths about the effects of the full moon are just that. Of course if someone has convinced themselves that they will be negatively affected during a full moon, they might bring trouble upon themselves.

http://www.ncbi.nlm.nih.gov/pubmed/8924138

3. Mar 13, 2012

### Ryan_m_b

Staff Emeritus
The fact that you find little/no references should tell you all you need to know. Considering all the billions of work hours that have gone into a variety of human biology fields it's pretty much ridiculous to suggest that a very obvious monthly cycle has not been noticed in all humans at some point.

Furthermore it is irrelevant whether or not we are made of water or anything else, gravity acts on mass regardless of what that mass actually is.

4. Mar 13, 2012

### Ivan Seeking

Staff Emeritus
I can think of one found in about half of all humans.

5. Mar 13, 2012

### collinsmark

It's not hard to do a few, rough calculations to prove this to yourself. For starters we can make a few approximations, while keeping in the spirit of the topic:
(a) Let's assume the moon is spherical.
(b) Let's assume that the moon is a constant 385 x 106 meters away. The moon's actual distance varies slightly (from around 360 x 106 to 410 x 106 m) due to the fact that it has an elliptical orbit and the fact we are on the Earth, and the Earth has its own radius and is rotating. But 385 x 106 meters is a rough approximation.

The gravitational acceleration caused by our moon can be determined by

$$a = G \frac{m}{r^2}$$

where G is Newton's gravitational constant, G = 6.67 x 10-11 [m3 kg-1 s-2]. The mass of the moon ,m, is 735 x 1022 kg. Plugging the numbers in gives us

$$a = (6.67 \times 10^{-11}) \frac{7.35 \times 10^{22}}{(384 \times 10^6)^2} \mathrm{[m \ s^{-2}]}$$

$$= 0.0000332 \ \mathrm{m/s^{2}}$$

The direction of that acceleration depends on where the moon is, of course. If you see the moon near the horizon, the accleration is coming from that direction. If you see the moon nearly straight up, the acceleration is directed in that direction. If it's a new moon at midnight, the direction is down.

Compare that to the acceleration caused by the Earth's gravitational attraction on our bodies (we being on the surface of the Earth), which is approximately $9.8 \ \mathrm{m/s^{2}}$, straight down. As you can see, the moon's gravitational pull is barely a drop in the bucket, compared to the Earth's.

You might have been curious about the tides. Yes, the gravitational pull from the Moon (and the Sun too) cause tides. And these tides cause the surface level of the water to raise and lower by somewhere on the order of 1 meter (roughly a meter -- of course that depends on some other geographical factors, but let's just say roughly around a meter or so, give or take.) Now consider that the average ocean depth is in the thousands of meters; ~3000-4000 meters is typical. The deepest part of an ocean is over 10,000 meters. So a tidal variation of about a meter isn't all that much. (I don't want to get into the math/physics of the tides though. It's significantly more complicated than the math used above, although it can be done.)

I don't know of such sources, but I haven't looked either . If you did start looking yourself, you should make an effort to remove biases such as brightness (i.e. reflection of the Sun's light off the Moon, directed back to Earth). When the moon is full, it's brighter out. It's pretty obvious. That alone might very well have an effect on people's habits and nighttime shenanigans. It seems to me as though you are interested in the variational effects of the moon's gravitational pull, which is far less noticeable to people than the moon's brightness.

Last edited: Mar 13, 2012
6. Mar 13, 2012

### mattbatson

excellent point about the water content...the people I'm discussing this with seem to liken it to the tides, and that is why they kept referring to water content.
They posted some study done in india back in the late 70's that showed a coorelation between full moon and crime at three different precincts...study is here...http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1444800/

I know that one statistical study means nothing...but apparently there are a couple more out there somewhere.

I've read many blogs and articles (including one from scientific american) that make some excellent points on how this is just not possible. But, the references are all books. I was hoping to find some actual scientific studies that show there are NO effects.

7. Mar 13, 2012

### collinsmark

By the way, due to the Earth's rotation and the moon's revolution, the direction of the moon's gravitational pull circles all the way around in the period of just over a day. This is true even if it's a new moon or a full moon or whatever (e.g. when the moon is full, it rises in the east and sets in the west in a single night -- it doesn't just sit up in the same right ascension all night).

If you looking for any effects of gravitational pull from the moon you should look for effects that have a period of 24.878 hours.

(Don't hold your breath trying to find anything though.)

Last edited: Mar 13, 2012
8. Mar 13, 2012

### mattbatson

thanks so much for that find!
really appreciate it.

9. Mar 13, 2012

### mattbatson

another excellent point
I hate it when facts and logic get in the way

10. Mar 13, 2012

### Staff: Mentor

That was published in the BMJ. I have seen so many crackpot papers posted there that I can't believe that they have not been downgraded yet.
Hoo boy.

I gave you one.

11. Mar 13, 2012

### Ivan Seeking

Staff Emeritus
I see one paper that talks about crime, and another that addresses hospital acitivities.

It has been suggested before that any evidence of increased criminal activities during a full moon might be attributed to increased light levels. It's easier to commit a crime when you can see - no gravity required.

12. Mar 13, 2012

### mattbatson

you did give me one, and i greatly appreciate it.

So BMJ has been involved in crackpot studies in the past....good to know

thx

13. Mar 13, 2012

### mattbatson

yes i can certainly see that.

thanks so much for all the responses...lots of great information

14. Mar 13, 2012

### Staff: Mentor

They still are. There was a link to a paper in one of their *journals* recently where the editor justified his reason for allowing the junk saying basically *it doesn't matter if it's not true as long as they can make a good argument*. Sorry, it matters at this forum if it is true.

More crackpottery at the BMJ link you posted

15. Mar 13, 2012

### Ivan Seeking

Staff Emeritus
However, there is still the distinction between the data, and the suggested explanation. A crackpot hypothesis doesn't necessarily invalidate the data, though it obvoiusly causes great concern over the validity of the entire paper.

16. Mar 14, 2012

### mattbatson

it seems as if the people doing the study had a pretty serious bias from the beginning?

17. Mar 14, 2012

### Staff: Mentor

Just a little.

18. Mar 14, 2012

### mattbatson

Too funny, I just got banned for three days from the other site that I was on.

It is one of those survivalist sites...survivalistboard.com...and in the 2012 section they were spouting off about brooms standing up on their own due to the increase geomagnetic field from the solar storms to lunar gravity causing all kinds of issues with humans, ha ha.

I started a couple of threads over there to present facts and to try and come to a logical conclusion to these "urban legends".
I guess enough of the members in that section of the forum messaged the moderator and they suspended me.

I almost had a suspicion that this might happen, as the members were getting overly agitated over a simple discussion where i used no condensending language or was disrespectful in anyway....so with that in mind, I was very careful to only stick to the evidence at hand and to bring no emotion into the thread.

Ah well, I think that many people will always be impossible to sway away from their beliefs with facts...as facts just seem to get in the way.

19. Mar 14, 2012

### Staff: Mentor

Well, you seem to be a sensible poster and you're welcome here.

20. Mar 14, 2012

### mattbatson

thanks
I am mostly reading back pages for now...
I wanted to study engineering in college, but couldnt even handle trig, so went a different direction.
Interested in science, just dont grasp the math

thanks for the welcome