What causes tides?

[SteveW 1,786]

...we went into more detail during the first year of secondary school and included the effect of the Earth's axis wobble, the magnetic poles and so on. What is interesting is how life evolved with respect to the orbit of the moon and tilt of the Earth, where, for example, sea Turtles lay their eggs above the high water mark of the highest tide.

[W2DR 1,851]

1 hour ago, martin-w said:

What about seasons, I bet many people don't know what causes seasons either?

Frankie Valli?

[Christopher Low 4,918]

It is interesting to note the difference between gravitational force and tidal force with respect to distance from an object. Gravitational force diminishes with distance based on an inverse square law, but tidal force is governed by an inverse cube law. This is why the gravitational force of the Moon exerted on the Earth is less than that of the Sun, but the tidal force is stronger.

Edited July 16, 2021 by Christopher Low

[Lawy 28]

4 hours ago, martin-w said:

 

Nope. The stars are in a completely different position from when the astrological charts were formulated. Its nonsense. 

The other point of course is that the gravitational influence is in accordance with the inverse square law, it falls of by the square of the distance. So the effect on us is non-existent given how far away the constellations are. 

As for the brain, the volume of water seems insufficient to be impacted significantly by the Moon's gravity. The gravitational field is too minuscule to impact the brain.  There were some Dutch researchers that suggested such a thing though. There are times when the Sun's gravity and the Moons team up to create higher tides. Full Moon and New Moon. No nutty behaviour is noted during  a New Moon though which would dispute the hypothesis. A Full Moon can impact sleep though which in theory could worsen psychiatric conditions. I know my OCD is far worse when I haven't slept. 

 

 

 

“It is the very error of the moon.
She comes more near the earth
than she was wont. And makes
men mad.”
—William Shakespeare, Othello

[sightseer 895]

4 hours ago, martin-w said:

Nope. The stars are in a completely different position from when the astrological charts were formulated. Its nonsense.

I actually wasn't thinking about any star other than our own and how its gravitational effects plus our moon's effects would vary throughout the year.

If we're not even sure how birds manage to migrate very long distances then how could we be sure an embryo/developing baby wouldnt be affected by varying forces -- some of which I suspect we're not even aware of (migration, turtles ... )

[SteveW 1,786]

The women's menstrual cycle mirrors the moon cycle.

The tides are not only with seas, but also the terrain and atmosphere undergo those forces which can affect the movement of the tectonic plates and the weather.

 

 

[ailchim 204]

Just two bits of useless knowledge. 

The Moon is gradually moving away from the Earth. Billions of years ago it was close enough for the Earth, a much larger body, to draw the rock the Moon toward it just as the Moon pulls the Earth's seas to it.  The Moon would have had a more pronounced egg-shape, with the pointy bit facing the Earth.  As the Moon always faces towards the earth, the force on the Moon's structure is at least static.  If the Moon had been rotating, the force would have been dynamic, potentially weakening it's structure as the rock itself was subject to a "tide".   The largest planets, Jupiter and Saturn, with much stronger gravitational fields, are thought to have "eaten" some of their moons which either fell into the planets or were destroyed by the tide-like effect of the huge planet's gravitational forces ripping them apart.

The seasons are caused not because the Earth is necessarily closer to the Sun, although its orbit is not perfectly circular, but because the Earth's axis is not perpendicular to the plane of the ecliptic: it leans over at an angle of about 23 degrees.  As it orbits the Sun, over the course of an Earth year, that 23 degree angle is progressively canted towards the Sun and then away,  When the North Pole end of the axis is canted towards the Sun, the Sun is above the horizon longer and so daylight hours are longer in the Northern hemisphere.  Also, sunlight falls more directly on the North, 23 degrees toward the Sun rather than 23 degrees away, so that in summer, the Sun's rays take a shorter direct path through the atmosphere and so are stronger when they reach the Erath's surface. 

In the winter, the axis cants away from the Sun, so he North pole points away from it.  Daylight hours are shorter and Sun rays come into the atmosphere at an oblique angle so they pass through more atmosphere before reaching the surface and so are weaker. 

Whatever is happening in the Northern hemisphere is reversed in the Southern, so Northerners have winter snow at Christmas and Southerners have a summer barbie on the beach!

 

 

    

[martin-w 3,115]

52 minutes ago, sightseer said:

I actually wasn't thinking about any star other than our own and how its gravitational effects plus our moon's effects would vary throughout the year.

Quote

Maybe there actually is a scientific component to astrology?

 

You said Astrology though, hence me referring to astrological charts. But yep, the two gravitational fields can combine during a full moon and new moon. No real evidence it has an impact though. Except in terms of more psychiatric issues due to lack of sleep during a full moon due to increased illumination. Don't the think the evidence is very strong for that either. Could be wrong. 

 

Quote

If we're not even sure how birds manage to migrate very long distances then how could we be sure an embryo/developing baby wouldnt be affected by varying forces -- some of which I suspect we're not even aware of (migration, turtles ... )

 

There's good evidence for how birds use the Earth's magnetic field to navigate. They have tiny concentrations of iron in their inner ears. They use the patterns of the sun and stars too. There's also some evidence they  use their brains olfactory mapping too. So yes, we have evidence for how they do navigate. No evidence for the gravitational field of the Moon or Sun impacting a foetus though. Science doesn't say no, just that there's no evidence. 

Corals spawn in accordance with Moon cycles, that's not the gravitational field though, its the level of illumination. Sea turtles use the light of the Moon also, not the gravitational field as far as we know. 

 

Quote

 

The supposed reason the lunar cycle affects our behavior has to do with the gravitational force of the moon. The most well-known effect of this gravitational force is the oceans' tides. Because our bodies are about 80 percent water, perhaps we, too, are susceptible to this gravitational force, just like the oceans? 

Not so, science has shown. And three key principles explain why the moon's gravity doesn't affect humans like it does the oceans, Scientific American reports. First, the gravitational forces of the moon are not powerful enough to have any effect on human brain activity. Plus, the pull of the moon only creates tides in open bodies of water, like oceans and lakes (but only to a very small, almost unmeasurable extent in even our largest lakes). Closed bodies of water, like the water in our bodies, are not affected by this gravitational force. And finally, the gravitational pull of the moon is just as strong during a new moon as it is during a full moon, and yet there are no corresponding theories about unusual human behavior during the new moon. 

 

https://www.reconnectwithnature.org/news-events/the-buzz/mythbuster-the-full-moon-change-human-behavior

Pretty sure even combining the Sun's gravity would not be significant either.  

Edited July 16, 2021 by martin-w

[SteveW 1,786]

During primary school, I think was in the last year, we went on a bus trip to Greenwich Royal Observatory. I think it was there that I remember an orrery which showed the tilt of the Earth in relation to the Sun and made the reason for seasons easier to understand. The North pole of the Earths axis points more or less to the North Star, Polaris. A visit to Greenwich would make a great day out.

[martin-w 3,115]

54 minutes ago, SteveW said:

The women's menstrual cycle mirrors the moon cycle.

The tides are not only with seas, but also the terrain and atmosphere undergo those forces which can affect the movement of the tectonic plates and the weather.

 

 

 

A more recent study, which the company who program the period tracking app Clue commissioned in 2016, also concludes that synchrony between menstrual and moon cycles is a “myth.”

https://www.medicalnewstoday.com/articles/menstrual-cycles-and-lunar-cycles-is-there-a-link

Tectonic plates do seem to be affected. High magnitude earthquakes seem to go up. 

[martin-w 3,115]

19 minutes ago, SteveW said:

During primary school, I think was in the last year, we went on a bus trip to Greenwich Royal Observatory. I think it was there that I remember an orrery which showed the tilt of the Earth in relation to the Sun and made the reason for seasons easier to understand. The North pole of the Earths axis points more or less to the North Star, Polaris. A visit to Greenwich would make a great day out.

 

Wanted to visit Greenwich, never got around to it. We were planning a visit but it didn't materialise. Now I'm in the Channel islands so miles away. 

[SteveW 1,786]

13 minutes ago, martin-w said:

synchrony between menstrual and moon cycles is a “myth.”

Apologies, 'mirrors' was the wrong word to use because it is correct there is no actual synchrony.

[jabloomf1230 2,439]

8 hours ago, SteveW said:

In the UK, seasons and tides are included with the primary school syllabus (under 12 year old).

Before you added the second post I was under the impression that you were made to memorize the tidal tables.

[n4gix 4,900]

9 hours ago, SteveW said:

In the UK, seasons and tides are included with the primary school syllabus (under 12 year old).

I'm rather certain that I was taught the same during sixth or seventh grade, but I'm slowing discovering that I am in that phase of life where I'm un-learning things at an increasing rate!  🤯

[SteveW 1,786]

On 7/16/2021 at 8:04 PM, jabloomf1230 said:

Before you added the second post I was under the impression that you were made to memorize the tidal tables.

I think that was a silly assumption, like assuming one would need to memorise the phone book to use a telephone. I think it is better to look for more realistic sense to other's posts in the first place.

I did a lot of sea fishing as a kid and to meet the high tide for night fishing we went on a Friday after school of every second week until the high tide got too late in the morning but go the following Friday whereby the process started again. In that sense we didn't really need to refer to tide tables.

The tilt of the Earth is what we were shown to cause tides, but later we were educated on other aspects like the wobble of the axis, the elliptic nature of the orbit of the Earth around the Sun, the increasing orbit of the Moon and so on.

On another note in the discussion about women's cycle being a "myth", I looked up that link. Being married to a woman I notice and having a mother and two sisters that they are usually "early" or "late", with what? Presumably with a recurring pattern closely matching the period of the Moon. It seems odd to me that there may be some that think the moon is causing some kind of synchrony with women. It is evident that the Moon has influenced the evolution of species but there certainly seems to be no synchrony with the tides.