orbit
The earths orbit around the sun is almost circular.
that earths orbit is elliptical
There is no 'periodic' change in the earths orbit. The orbit is elliptical and over time (a great many years) becomes less so.
The earths orbit around the sun is almost circular.
Because it is pulled in by the earths gravity and therefore orbits the earth.
A revolution: The Earth revolves in an elliptical (oval) orbit around the Sun. This orbit is planetary; the Sun is a star, and a large object that orbits a star is known as a planet.
Yes. They orbit the Sun and as per Kepler's first law they follow an elliptical path. Do note that a circular orbit is a special type of elliptical orbit.
Not much would change. Note that the seasons are NOT related to changes in the distance from the Sun.
As an elliptical orbit is any orbit that isn't perfectly circular, everything has an elliptical orbit. The planets Mercury and Pluto have the most elliptical orbits of the planets, and are easily seen to be oval shaped. Comets also have highly elliptical orbits.
All the planets move with an elliptical orbit, but with a very low eccentricity.
The planet with the most elliptical orbit is Mercury. Second is Mars.