How did people find out the earth went in sircles?

Answer 1

If you go outside at the same time every night for a year, and keep track of the

patterns of stars in the sky and how they change, there are two ways to explain

what you see happening:

1). The Earth is in the center of everything, and all of the stars in the sky revolve around the Earth.

2). The Earth travels a nearly-circular path around the sun once a year.

Explanation #1 was the more popular one until about 600 years ago. At that time,

a lot of people began to suspect that maybe it is not the best explanation for what

we see.

At the same time, mathematicians developed ways to demonstrate that Explanation #2

can match the motions we see in the sky even better than Explanation #1 can.

So Explanation #2 has become the more popular one since then.