Geology I

Cycle III

John Dewey High School

Mr. Klimetz

Earth's Shape, Size, and Surface

Fact Sheet

Earth's Shape

1.   The actual shape of the Earth is an oblate spheroid, whereby

the polar diameter is less than the equatorial diameter.

2.   The flattening of the Earth at the poles and the subsequent

bulge at the equator is due to the Earth's rotation and its

elasticity.

3.   Evidence of Earth's shape is derived from:

q Satellite photographs.

q Measurement of the variation in Earth's gravitational force

at different locations.

q The systematic change in the altitude of Polaris with

change in latitude.

q The curved shadow of Earth's surface projected onto the

Moon during lunar eclipses.

q The apparent disappearance of a seaship's mast/funnel

beneath the horizon as it moves out to sea.

Earth's Size

1.   The Earth's equatorial circumference is 40,074 kilometers (or 25,046 miles).

2.   The Earth's polar circumference is 40,007 kilometers (or 25,004 miles).

3.   The Earth's equatorial diameter is 12,756 kilometers (or 7,927 miles).

4.   The Earth's polar diameter is 12,714 kilometers (or 7,900 miles).

Earth's Surface

1.   The total surface area of the Earth is 510 million square kilometers.

2.   The total surface area occupied by land is 149 million square kilometers (or

29% of the total).

3.   The total surface area occupied by sea is 361 million square kilometers (or

71% of the total).