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First of all, we must note that the universe is spherical.

I shall now recall to mind that the motion of the heavenly bodies is circular, since the motion appropriate to a sphere is rotation in a circle.

We regard it as a certainty that the earth, enclosed between poles, is bounded by a spherical surface.

'Earth' is a silly name for this planet.

You can't take sides when you know the earth is round.

Nature is an infinite sphere of which the center is everywhere and the circumference nowhere.

Planets' orbits are elliptical. It's a very pleasing shape.

It is well that the earth is round that we do not see too far ahead.

Thanks to the fact that the Earth isn't a perfect sphere, and invoking a bunch of Newtonian physics, you can deduce that our planet wobbles, too, taking roughly 26,000 years to trace out a small circle on the sky, a phenomenon known as precession.