Moon's Gravitational Pull?

In summary: Thanks, Dave.In summary, the gravitational pull of the moon raises the water level in the open sea by a few inches, but the effect on human circulation is negligible.
  • #1

FeDeX_LaTeX

Gold Member
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13
Hello;

We know that waves of the sea are caused by the gravitational pull of the moon. But if this is true, why doesn't this happen with lakes or cups of water? What about things like molecules in the air?

Thanks.
 
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  • #2
The ocean tides are affected because there is water available (from the rest of the planet). Waves are something else (wind primarily). There is no reservoir of water to fill cups or lakes. Large lakes may have waves (from wind).
 
  • #3
Hello FeDeX_LaTeX! :smile:
FeDeX_LaTeX said:
We know that waves of the sea are caused by the gravitational pull of the moon.

No.

Most waves in the sea, even the amazingly big ones, are caused by wind etc.

All the Moon does is raise the water level in the open sea by a few inches (and when this tiny wave reaches the continental shelf, the shallower water makes this Moon-wave larger).

This few inches (I forget the exact figure) is the maximum difference in height between the actual (Moony) line of equal gravitational potential joining opposite sides of an ocean, and the perfectly circular arc centred on the centre of mass of the Earth.

For the width of yer average ocean, that's a few inches.

For lakes or cups of water, it's proportionately smaller. :smile:
 
  • #4
More than a few inches, tiny-tim. Its about a meter, peak-to-trough.
 
  • #5
Curious, does this effect also influence the human circulatory system?
(Sorry for being slightly off-topic)
 
  • #6
Well, jeez. "No" is too short an answer.

No, tides do not affect human circulation.
 
  • #7
pallidin said:
Curious, does this effect also influence the human circulatory system?
(Sorry for being slightly off-topic)

Earth's gravity is one g (depending on where you are). Now, a variation in acceleration (such as riding up and down in an elevator) can cause more or less blood to flow from your heart to your brain.

However, the acceleration due to the Moon, on Earth's surface, is typically around a ten millionth of a g. I think it's safe to say that the Moon's gravity has little, if any, effect on the human circulatory system.
 
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  • #8
Dang, I can't blame my transient bizarre behavior on a full moon. :mad:
 
  • #9
D H said:
Well, jeez. "No" is too short an answer.

No, tides do not affect human circulation.
it would be foolish to say 'No.' sure, the effect of the tidal force of the moon on your circulatory system is immeasurably small, but to say it has no effect is denying that two numbers no matter how similar, are different. 2.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001 and 2 are two completely different numbers, to deny that is to devalue math to the level of smashing rocks together.
 
  • #10
AUK 1138 said:
are two completely different numbers, to deny that is to devalue math to the level of smashing rocks together.

Which would be great - if this were a math question. :uhh: But it's not; it's a physio-biology question.

And the answer is still no, there is no measurable effect whatever of the moon on the human circulatory system.
 
  • #11
DaveC426913 said:
And the answer is still no, there is no measurable effect whatever of the moon on the human circulatory system.

Thanks, Dave.
I had posted my side-question not to be funny(though my response was), rather that some people believe tidal effects affect human behavior. So I was genuinely curious.
You and others cleared-up that myth, at least for me.
So, back to topic!
 

1. How does the Moon's gravitational pull affect the Earth?

The Moon's gravitational pull affects the Earth in several ways. First, it causes the tides in the ocean, as the Moon's gravity pulls on the Earth's water. It also affects the Earth's rotation, slowing it down slightly over time. Additionally, the Moon's gravitational pull helps stabilize the Earth's tilt, which is important for maintaining the seasons.

2. Is the Moon's gravitational pull stronger or weaker than the Earth's?

The Moon's gravitational pull is much weaker than the Earth's. The Earth's mass is about 81 times greater than the Moon's, so it has a much stronger gravitational pull. However, because the Moon is much closer to the Earth than any other celestial body, its gravitational pull still has a significant influence.

3. Can the Moon's gravitational pull affect human behavior or emotions?

There is no scientific evidence to suggest that the Moon's gravitational pull has any direct effect on human behavior or emotions. While some studies have shown a correlation between the lunar cycle and certain behaviors, such as sleep patterns, there is no known mechanism for the Moon's gravity to directly impact human behavior.

4. Does the Moon's gravitational pull ever change?

Yes, the Moon's gravitational pull is constantly changing. This is due to the Moon's orbit around the Earth, which is not perfectly circular. As the Moon moves closer to the Earth in its orbit, its gravitational pull increases, and as it moves farther away, its pull decreases. This also causes variations in the tides on Earth.

5. How does the Moon's gravitational pull compare to other celestial bodies?

The Moon's gravitational pull is much weaker than larger celestial bodies, such as the Sun or Jupiter. However, it is stronger than smaller objects, such as asteroids or comets. The strength of a celestial body's gravitational pull is determined by its mass and distance from other objects, so the Moon's pull is unique to its size and proximity to the Earth.

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