Ellipse

I'll leave it to you to think about how it would change if you had an elliptical shape like this

A special case of this is the circular orbit, which is an ellipse of zero eccentricity.

However, because Earth's orbit is technically an ellipse, even though it doesn't look like one, and the sun isn't quite exactly at the center, it means that our distance from the sun does change through the year.

The theory is that if we follow the sight of a person looking at a sphere, and we project that on the surface, we wouldn't get a circle, but an oval shape.

Only in the 1970s was it realized that conjugacy based methods work very well for partial differential equations, especially the elliptic type.

Because the moon doesn't have an atmosphere you can do an elliptical orbit and miss it by 10 feet if you want.

And then we can use that and we know about the circumference of this loop de loop and we're going to assume that it is perfectly circular for our purpose although it looks like it's a little bit egg shaped in reality or elliptical

لقد قام كبلر بهدم صرح فكري عمره أكثر من ألفي عام و استبدله بقانونه الأول عن حركة الكواكب فكل الكواكب تدور في شكل بيضاوي حول الشمس

So it is true that Earth's orbit is not a perfect circle around the sun, although it's pretty close, but it's not a perfect circle, it has a slighty elliptical shape, and because of that there are times of the years where we are closer to the sun, and there are times when we are furthest from the sun.