Very often people try to understand the bulge in terms of a force equilibrium: often there are statements about a balance between a centripetal force and a centrifugal force. However, it's not a good idea to try and understand equatorial bulge in terms of an equilibrium between forces. It's when you understand it in terms of an energy equilibrium that you can see hoe it ties in with other phenomena in physics.
Because of a planet's rotation around its own axis, the gravitational acceleration is less at the equator than at the poles. In the 17th century, following the invention of the pendulum clock, French scientists found that clocks sent to French Guiana, on the northern coast of South America, ran slower than their exact counterparts in Paris.
Any object that is stationary with respect to the surface of the Earth is in actual fact following a circular trajectory, circumnavigating the Earth's axis. Pulling an object into such a circular trajectory requires a force. The acceleration that is required to circumnavigate the Earth's axis along the equator at one revolution per sidereal day is 0. Providing this acceleration decreases the effective gravitational acceleration.
At the equator, the effective gravitational acceleration is 9. This means that the true gravitational acceleration at the equator must be 9.
At the poles, the gravitational acceleration is 9. The difference of 0. I have glossed over differences in density now. The Earth's core is much denser, and there are other, smaller density variations. In summary, there are two contributions to the fact that the effective gravitational acceleration is less strong at the equator than at the poles. About 70 percent of the difference is contributed by the fact that objects circumnavigate the Earth's axis, and about 30 percent is due to the non-spherical shape of the Earth.
Many plant and animal species thrive in equatorial climates. The Amazon and Congo rain forest ecosystem s, for example, are amazingly rich in biodiversity. A single hectare 2. The equatorial savanna of Kenya includes mammals such as lions, cheetahs, and elephants. The chilly equatorial Andes are famous for its camelid species: llamas, alpacas, vicunas, and guanacos. Earth's equatorial bulge pushes Mount Chimborazo, near the Equator in the Ecuadorian Andes, further from the center of the Earth.
However, elevation is measured from sea level, not the center of the Earth. Mount Everest is 8, meters 29, feet above sea level, while Mount Chimborazo is just 6, meters 20, feet above sea level. Crossing the Line Sailors have elaborate rituals and celebrations when they cross the Equator, which they call crossing the line. Sailors who have never crossed the line are called pollywogs. Pollywogs are usually the target of embarrassing practical jokes.
Short Sunsets The time it takes for the sun to set and rise at the Equator is the fastest on Earth. The transition from day to night takes only a few minutes. Regions are the basic units of geography. Sea level is determined by measurements taken over a year cycle. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.
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After traveling about 50 miles north, the puck reverses its direction and starts to move south. At the same time, the Coriolis force, another force that emerges in rotating systems, drives the puck to the west.
Part of the reason is that as Earth spins, objects closer to the equator are moving faster than objects closer to the poles, since those points have to travel farther to complete an orbit in the same amount of time. It's similar to how a track athlete in an outside lane has to run faster to keep up with a runner in an inside lane. As the puck travels south, the land beneath it is moving faster eastward, so the puck appears to move west.
Furthermore, as the puck gets closer to the equator, it gets farther from Earth's axis of rotation, and to conserve angular momentum, the speed at which it moves to the east slows. It's the same reason why a figure skater spins faster with their arms tucked in, and slower with their arms outstretched. This slowing further pushes the puck to the west. As the puck travels to the southwest, it speeds up until it crosses the equator, at which point it starts to slow, as the centrifugal force pulls it back to the equator again.
The puck gets as far south as Argentina, exactly as far below the equator as its highest point above it, before returning to the north.
The puck will continue to zigzag between the northern and southern hemispheres while moving to the west. On a spheroidal Earth, the centrifugal force and gravity cancel each other out, leaving just the Coriolis force to affect the puck's movement.
The Coriolis force is what gives hurricanes and cyclones their circular movement, and the puck behaves similarly, rotating clockwise while hovering near Spain and Portugal. The puck would move differently if the hockey player started at a different location and shot the puck in a different direction, and you can play around with different starting points in this visualization software designed by the paper's authors.
But these examples show the profound effect Earth's shape has on movement on its surface. Boyd Edwards said that Earth's spheroidal shape has implications for aviation, meteorology, oceanography and other fields, since the Coriolis force will affect motion, but the centrifugal force will not.
Inside Science is an editorially independent publication of the American Institute of Physics. But in , that trend suddenly and unexpectedly reversed. Cox and his colleague Benjamin Chao studied observations from nine satellites and found that gravity at the equator has become stronger. This implies the circumference had expanded — by something like a millimeter. The new trend implies that there has been a transfer of mass from high to low latitudes.
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