THE earth and moon rotate around each other, each pulling the other towards itself. The moon attracts every piece of matter on earth.
[ihc-hide-content ihc_mb_type=”show” ihc_mb_who=”2,3,5″ ihc_mb_template=”1″ ]Since gravity is inversely proportional to the square of the distance, this force is greater on the side of the earth closer to the moon, and lesser on the side of the earth further from the moon.
Since the earth is quite a rigid object, this difference in forces fails to deform the earth (much). However, it succeeds quite well in deforming the oceans – which are not as rigid.
Since the waters on the moon side are attracted more strongly than average, they tend to bulge towards the moon, hence causing a high tide.
The waters on the opposite side of the moon, since they are attracted less strongly than average, tend to ‘lag behind’ the rigid earth, and bulge away from the moon, which in this case, is also away from the earth, again, causing a high tide.
Low tide occurs at about right angles to the moon, where the force on the waters match the average pull of the moon on the earth closely.
On the other hand, although the gravitational pull of the sun on the earth is larger than that of the moon, due to the much greater distance, the force changes very little from one end of the earth to the other.
Since it is the difference in the force than the average magnitude of the force that matters for creating tides, the net effect is much less than that for the moon.
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