The Earth's orbit is an elipse, not a circle. Ellipses have two fulcrums (fulcri?) equidistant from the center (still inside the elipse) and of equal size. So the sun is one fulcrum but there is nothing else anywhere near that size to be other fulcrum so how does that work?
shareThese are the things where people do not get the literal meaning of the use of a word that in this context is highly exaggerated.
Neil deGrasse Tyson has once made a really good comparison.
The earth isn't a perfect sphere, centrifugal forces make it thicker around the equator, most of us know that, but hardly anyone knows how much (or better how little) thicker that actually is.
If you'd take all the water off and shrink just the rocky surface of the earth to the size of a billard ball, including all the deepest points under water, all the tops of the highest mountains and including the thicker equator, that ball would still be smoother and closer to a perfect sphere than any billard ball ever machined.
Do the math, the lowest points under water and the highest mountains have a difference of roughly 20 km (a bit over 12 miles) in altitude, earth has a diameter of 12,700 km (almost 7,900 miles) and 20 out of 12,700 gives 0.157%.
Same thing with the elliptical orbits of the planets around the sun, they are measurable, but relative to the diameter of the orbits it's still as close to a circle as it gets.