Here is a question that I have wondered about. What would the map of the world look like if the earth was not rotating?
The spin of the earth produces centrifugal force. The earth is solid while the oceans are fluid. This means that the centrifugal force should pull water toward the equator so that the seas should, on the average, be deeper in the tropics than at higher latitudes.
We can see this centrifugal force in the movement of glaciers during the ice ages. Glaciers begin to form when the temperature gets cold enough that the snow of a winter hasn't entirely melted when the snow of the next winter begins. Snow piles up year after year, decade after decade, and century after century. The snow is compacted into ice by the weight of the snow above it. The result is a vast sheet of ice maybe one or two km thick, limited in thickness only by the altitude of the cloud from which the snow falls.
The centrifugal force of the earth's spin is greatest toward the equator. This means that there is a difference in the centrifugal force on the glacier, with the greatest force closer to the equator. This has the effect of pulling the entire mass of ice toward the equator, and this is why glaciers move.
The spin of the earth also has a pronounced effect on the winds. The prevailing winds on earth are alternating bands of prevailing west or east winds, while north and south winds are intermittent. Circular storms like hurricanes pick up their cyclical motion from the spin of the earth.
So if the spin of the earth affects glaciers and winds then shouldn't it have an effect on the water in the oceans? It does affect ocean currents but if the centrifugal force pulls glacial ice toward the equator, although the sheet will move only if it is vast enough for there to be enough difference in the centrifugal force closer to and further from the equator to move it, then shouldn't it also pull the water of the oceans toward the equator?
This would mean that, on the average and with other factors being equal, water would be deeper around the equator than at higher latitudes. This in turn would mean that there would be less land and more water composing the earth's surface around the tropics than there would have been if the earth were not spinning.
Indeed the deepest points of both the Indian and Pacific Oceans are within a few degrees of the equator. The deepest point of the Atlantic Ocean is about 18 degrees from the equator.
The surface of the entire earth is about 72 percent water and 28 percent land. It is true that the distribution of land on earth is very uneven and follows no pattern. The vast majority of the earth's land area is in the northern hemisphere so that the northern hemisphere is about half land while the southern hemisphere is about 90 percent water.
But the equator is between the northern and southern hemispheres and we might have the expectation that the surface over which the equator passes would be about 72 percent water and 28 percent land. But the percentage of land would be expected to be less, and that of water greater, if the centrifugal force of the earth's rotation did, in fact, pull water toward the equator.
This is indeed the case as the surface over which the equator passes is only about 21.4 percent land, and 78.6 percent water. The four significant land masses over which the equator passes are South America, Africa, Sumatra and, Borneo.
The light blue on the following map from Google Earth is the vast shallow area of sea between Indonesia, Malaysia, Vietnam and, Thailand. Might this have been land if the earth didn't spin, or rotated more slowly so that there wouldn't be as much centrifugal force to draw water to the tropics?
The following map from Google Earth makes it seem as if Australia and Papua New Guinea are really one land mass until the light blue shallow sea flooded in because the centrifugal force of the spin of the earth pulled water toward the equator.
There is a wide area of shallow sea off the Gulf Coast of Florida. If the earth didn't spin, or spun much slower, might Florida have much more real estate than it does now? Image from Google Earth.
On the other hand, what if the earth rotated more slowly so that days were longer? Might Britain and Ireland be joined to continental Europe, as they once were, until the shallow sea separating them was formed by glacial movement? Because the spin of the earth wouldn't be pulling so much water to the tropics. Image from Google Earth.
The spin of the earth is very significant, relative to it's scale. A point on the equator is moving eastward at about the speed of sound. It actually seems that there should be even more difference in water depth between the tropics and the higher latitudes.
The earth actually does bulge at the equator due to the centrifugal force of rotation. The equatorial diameter of the earth is a little bit more, relatively speaking, than the polar diameter. If not for this bulge, if the earth were a perfect solid, and water was drawn to the tropics by the force of the spin, then there may well have been no land at all around the equator.
The fact that the earth bulges like this is what I consider proof that there must be magma, hot molten rock, beneath the surface all over the world. This would be a requirement for my geologic theory as described in the compound posting "The Story Of Planet Earth", on the geology blog, www.markmeekearth.blogspot.com . This theory, based on Continental Asteroids and the emergence of magma from below, leaves no major feature of the earth's surface, whether on land or the seafloor, unexplained. It has indeed recently been confirmed that there is a layer of magma, about 150 km down, across the entire earth.
