The formation of our solar system from a singular nebula raises an intriguing question: why did each planet develop with a ...

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit before shoving four of the solar system's planets onto a different course.

The enormous visitor to our solar system may have been about 8 times the mass of Jupiter, and come nearly as close to the sun ...

While the composition of gas and dust in a molecular cloud is fairly uniform, everything changes once a star begins to form.

The eight planets travel around the Sun at different speeds. These lines show us the paths they take which we call orbits. On a clear night from Earth we can sometimes see the five planets which ...