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Himal kharel
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Tides in sea are caused not by moon but by sun. Though the force of attraction caused by sun is much more than that by moon.
Why do you think that?Himal kharel said:Tides in sea are caused not by moon but by sun.
olivermsun said:Was the OP a question?
Phyreak said:you made a small mistake. you mistaken sun with moon.
Sun is at huge distance and big. so fairly it attracts a large part of crust with fairly equal force.
but moon is at small distance and is small. so its force is more concentrated on a part of Earth's crust causing tides.
JaredJames said:Nope, try again.
AlephZero said:Actually, I think Phyreak has the kernel of the right answer there, though it's not very well explained in English-as-a-foreign-language.
Phyreak said:you made a small mistake. you mistaken sun with moon.
Sun is at huge distance and big. so fairly it attracts a large part of crust with fairly equal force.
but moon is at small distance and is small. so its force is more concentrated on a part of Earth's crust causing tides.
Drakkith said:Also, the force of gravity from the moon on the Earth is MORE than the sun is because of the extreme distance of the sun compared to the moon. (I think at least) The force due to gravity falls off greatly with distance. If you double the distance you have 1/4 the force. I forget the technical term for describing this, something like falling off at the square of the distance or something.
RedX said:The Earth revolves around the sun, so the sun's gravity is greater on the Earth than the moon's gravity on the earth. However, the Earth's gravity is greater on the moon than the sun's gravity is on the moon, so the moon rotates around the earth.
olivermsun said:It's the gravitational gradient that matters to a tide, so the sun can do a perfectly good job of "capturing" the Earth while the moon stirs up a hefty tide. I think that's what some of the posters have been describing above.
Sun's mass is about 27000000 times greater than that of the Moon! Even the larger distance cannot compensate for it. If you apply Newton's law to point masses of Earth, Moon and Sun you will find that Sun attracts Earth much more than Moon attracts Earth.So the sun must around 100,000 times the size of the moon to be as influential.
jschmidt said:I think for understanding tides, it's very helpful to understand that a tide is kind of less a 'lifting' of the water due to the gravity of the moon, and more of a wave. It's a wave on the surface of the ocean where the 'crest' of the wave is, more or less, at the point on the surface of the ocean which is closest to the moon.
This wave is hundreds or thousands of miles across (from east to west; that is, the wavelength of the wave is like a thousand miles), but the height/amplitude of the wave is only a few feet high. The "rising tide" effect happens as the crest of the wave gets nearer and nearer to the shore. Just like when 'regular' small waves (which might be 10 feet across) come ashore, they seemingly 'rise up' - because they are in motion, the water is getting shallower, and so the shallow coast line 'pushes' the wave upwards as it moves in).
The gravitational attraction from the moon, while fairly weak, is *strong enough* to cause the water to flow and create the "tidal wave", and the tidal wave then causes the tide to rise and fall. At least, that's how I remember it being explained to me, and makes sense to me.
RedX said:So would this imply that the angular speed at which the moon rotates around the Earth (about 24 hours for one revolution) is equal to the angular speed of the tidal wave, since the crest is always more or less on the surface of the ocean closest to the moon? If you dip a stick into the water, isn't the speed at which ripples propagate (the speed of the wave) determined by the medium itself, rather than on how you dip the stick in the water? So how can the moon affect the speed of the ripples it causes?
olivermsun said:The moon's (or sun's) gravity is pulling more on the side of the Earth closer to it than the other side. This causes an elongation of the "earth sandwich" in that direction. Hence two bulges in the ocean, one on each side. The Earth turns "under" the moon (sun), but the bulges try to stay stationary relative to the moon (sun), so they move around the surface of the ocean with some lag.
Tides are primarily caused by the gravitational pull of the moon and sun on the Earth's oceans.
Tides occur twice a day because the Earth rotates while the moon and sun remain in relatively fixed positions, causing the ocean to experience two high tides and two low tides in a 24-hour period.
The moon has a greater influence on tides because it is closer to the Earth and has a stronger gravitational pull. However, the sun also plays a role in tides, particularly during spring tides when it aligns with the moon to create higher high tides and lower low tides.
Spring tides occur when the sun, moon, and Earth are aligned and have the greatest gravitational pull on the Earth's oceans, resulting in higher high tides and lower low tides. Neap tides occur when the sun and moon are at right angles to each other, resulting in weaker tides.
Tides play a crucial role in the life cycles of many marine species, such as sea turtles and certain fish, by providing access to feeding and breeding grounds. They also help circulate nutrients and oxygen in coastal ecosystems. However, extreme tides, such as storm surges, can also cause damage to these ecosystems.