If you had to prove the earth was round how could you do it If you had to prove the earth was round how could you do it? The Flat Earth Theory Video: President of Flat Earth Interview

There’s 5 main observations you could use to theorize that the earth is not flat 1.) Ships seem to disappear into the horizon. This is caused by the curvature of the earth’s surface

2.) Observations of the movements of planets and stars The sun appears to move across the sky as do the constellations and moon in the sky at night

3.) The changing altitude of Polaris

Wait, where is Polaris? Polaris is located over the North pole, but its visual altitude changes depending on where in the world you are

Polaris/North Star’s position changes with latitude. A person at the equator will see the north star at the horizon (the earth’s surface), & as he travels north, it will rise in the sky *The altitude of Polaris= your Latitude!

3.) Lunar Eclipses During a lunar eclipse, the earth's shadow cast on the moon is in the shape of an arc (only spheres cast circular shadows)

At North Pole (Lat. 90º N), Polaris is 90º above horizon

New York City (41º N), Polaris is 41º above horizon

Equator (Lat. 0º), Polaris is 0º above horizon

Back to other reasons we KNOW the Earth is not flat…

4.) Measurements of Gravitational Pull Gravity is measured to be roughly the same everywhere on the planet +/- 1% . If the earth were not a sphere, it would change

Wait…what did you say about gravity? If our planet were a PERFECT sphere, gravitational pull would be the SAME everywhere, so what is this +/- 1%?

Earth is a Oblate Spheroid -Earth “bulges” about 40 (km) at Equator; gravitational pull is less (further from the core) Which means you actually weigh less at the equator than at the poles! (~0.5% less) 1 N=0.22481 lbs F g=9.81 m/s-2  9.780 m·s−2 at the equator to about 9.832 m·s−2 , the speed of an object falling freely near the Earth's surface will increase by about 9.81 metres (about 32ft) per second every second

5.) Direct Observation Technology NOW allows us to make a direct observation that the earth is a sphere ; obviously best evidence

You may have made your own direct observations…I did 