An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit ...

When you first learned about the Solar System, you probably saw diagrams that made it look orderly, with planets arranged in circular orbits around the Sun on a flat disk. But in reality, our Solar ...

Orbits of natural bodies in the universe are usually not perfectly circular — they are elliptical. Some orbits are ever so slightly elliptical (like a somewhat squashed circle, or, in ...

Ever since Isaac Newton famously talked about gravity, its dominance as a force in our solar system has been well known. It's ...

However, it was not until Kepler's observations that the planets followed elliptical orbits around the sun (rather than circular orbits) that astronomical models matched observations of the ...

Scientists now think that a mysterious object massive enough to have gravitational interactions with the Solar System’s disk ...

An object moving in a circular orbit at a constant speed has a changing velocity. This is because velocity is a vector quantity that depends on speed and direction. The object in orbit is ...

However, none of the eight planets, including Earth, have perfectly circular orbits. Plus, the planets' paths don't lie precisely on the same plane. Compared with Mercury (whose orbit, within our ...