This diagram offers a hint at one of those ideas ... Newton’s descriptions of gravity explained Kepler’s calculations regarding elliptical orbit and Kepler’s theories regarding the ...

After performing de-orbit maneuvers in February and March 2019, the Van Allen Probes' highly elliptical orbits will gradually tighten over the next 15-25 years as the spacecraft experience ...

Some orbits are ever so slightly elliptical (like a somewhat squashed circle, or, in astronomical terms, an orbit with low eccentricity), whilst some appear rather flattened (highly eccentric orbits).

According to one professor of earth and planetary sciences, parameters such as planetary gravitational attractions, the Earth's elliptical orbit around the sun and the degree of tilt of our planet ...