How to measure the size of the earth?

Answer 1

The easiest way, if you don't want to travel a great distance, is to measure the "dip" of the horizon.

You will need a tall tower (the taller the better), and a device that can measure angles accurately. A surveyor's transit, or theodolite, will do nicely.

Measure the height of the tower. Take the transit up to the top of the tower and level it. Then determine difference between horizontal, and the real horizon. The visible horizon will be LOWER than horizontal because of the Earth's curvature; this is called the "dip" of the horizon.

Knowing the height of the tower and the dip angle, you can compute the size of the Earth using a little basic trigonometry.

Answer 2

Use trig... a couple of towers that are visible from a distance and with a known observation height, measure the angle to the observation point. Then calculate the curvature and base the measurements on a round Earth. You will be a bit off because the Earth is an ellipsoid but Erasthenous or whatever his name was got it pretty well correct.

Answer 3

THIS IS LIZZ's FRIEND TALKING:

ok, im an earth science nerd, but the formula was made by erastothenes. set up a proportion- distance from something over angle of earth = u kno what, i cant remember.. but, i know a source. look up on google "eratosthenes method" ok?

Answer 4

Equatorial radius 6,378.137 km
Polar radius 6,356.752 km
Mean radius 6,372.797 km
Equatorial circumference 40,075.02 km
Meridional circumference 40,007.86 km
Mean circumference 40,041.47 km
Surface area 510,065,600 km²
Land area 148,939,100 km² (29.2 %)
Water area 361,126,400 km² (70.8 %)
Volume 1.083 207 3×1012 km³
Mass 5.9742×1024 kg

Answer 5

You're gonna need a really, REALLY big thing of measuring tape.

Answer 6

http://www.karlscalculus.org/measureearth.html