Is the diameter of earth larger when measured from pole to pole or when measured at the equator?

Answer 1

From the NASA site: "The diameter of Earth from North Pole to South Pole is 7,899.83 miles (12,713.54 kilometers), but through the equator it is 7,926.41 miles (12,756.32 kilometers). This difference, 26.58 miles (42.78 kilometers), is only 1/298 the diameter of Earth." Thus the earth is 25 miles or 42.78 km wider than it is tall, giving it a slight bulge at the equator. This is only 0.3%, too small to be seen visually.

Answer 2

The planet Earth is not a complete and perfect sphere, as I hope you already know. It's constant rotation has caused it to somewhat morph into a very feint egg shape of sorts. To prove this, you can take a ball and a string and twirl it around. The length from where you hold the string to the end of the ball would be the radius of the Earth. When you swing the ball on the string, the ball will be pulled outwards, and if swung fast enough, will stretch, or even break the string, or simply cause the ball to detach from the string. Now when we apply that to the Earth, from the equator to the core would be the end of the ball to where you hold the string. When the Earth 'swings', it will pull outwards, and 'stretch' the Earth.

And now that you (hopefully) understand that concept, the equatorial diameter is greater than the polar diameter because the Earth rotates at it's equator, not its poles.

Answer 3

The reason is because Earth has a slightly oblate shape.

Answer 4

On planets the equatorial diameter is usually larger than the polar diameter because the rotation of the planet causes it to deform slightly from a sphere, due to centrifugal force.

Answer 5

Earths equatorial radius ~ 6,378 km
Earths polar radius ~ 6,357 km

Answer 6

The equatorial radius of the Earth is about 21 km larger than its polar radius.

Answer 7

The earth is larger around the equator, than around one of the meridians.

The earth is not perfectly spherical, but squashed, known as an 'Oblate Spheroid'.

Answer 8

The diameter is greater at the Equator, because the Earth is not a perfect sphere but is flatter toward the Poles.

Answer 9

Larger at the equator

Answer 10

Centrifugal force