[ad_1]
The Earth and most rotating bodies have an oblate spheroid shape due to forces from rotation. An ellipse rotated about its minor axis creates this shape, with the minor axis as the line through the planet’s center forming the poles. The Earth is wider at the equator, making it more like an oblate spheroid than a sphere.
An oblate spheroid is a three-dimensional solid and is most easily described as a sphere that has been compressed from top to bottom, causing the equator to bulge. The Earth and most rotating bodies in space have this shape. The forces acting on the Earth as a result of its rotation produce this shape. These forces cause the mass of the Earth to try to fly outward as the planet rotates, but gravity holds it together.
An ellipse rotated about its minor axis will describe the three-dimensional object known as an oblate spheroid. The ellipse is a two-dimensional construct of an oval shape, defined in geometry as the shape that results from the intersection of a flat plane with a cone. It has two aces: major and minor. A line passing through the center of the ellipse and with its endpoints located the furthest apart is the major axis of the ellipse and is its maximum possible diameter. The minor axis passes through the center of the ellipse, has its endpoints at minimum distances from each other, and is the smallest possible diameter of the ellipse.
This can be visualized by imagining an ellipse so that the longest dimension is horizontal. The minor axis is a vertical line through the center of the ellipse connecting the top and bottom. The contour of the ellipse is rigid and the minor axis is its point of rotation. Rotating the ellipse about the minor axis creates an oblate spheroid. The ellipse can be viewed as the outline of a planet, with the minor axis as the line through the planet’s center forming the north and south poles. There are a number of mathematical equations to describe these types of solids in geometry and trigonometry.
While many people assume that the Earth is a sphere, that’s not the case. Of course, variations in surface features would preclude describing the Earth in terms of any perfect solid shape, but when accounting for the scale of the planet versus the size of its surface features, these shapes can be used as approximations. In fact, the shape of the Earth looks more like an oblate spheroid than a sphere. The difference is very small, but the Earth is about 42 miles (65km) wider at the equator than it is from pole to pole. This means that a person standing at either pole is approximately 21 miles (32km) closer to the center of the Earth than a person standing at the equator.
[ad_2]