I can think of one...
there is gravity pulling everything to the center of the earth, therefore the earth is spherical because gravity is equally distributed, pulling everything to Earth's center equally.
Answer:
Astronomers used the cross-staff for measuring the angle between the directions of two stars. ... Ships' officers used it to measure the elevation angle of the noontime Sun above the horizon, which allowed them to estimate their latitude
Explanation:
Google
“A tidal wave is a regularly reoccurring shallow water wave caused by effects of the gravitational interactions between the Sun, Moon, and Earth on the ocean.”I hope this is what you meant by your question
