The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

Stargazers will be treated to a rare seven-planet alignment in February. This is what scientists hope to learn.

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

The building blocks of life could have been delivered to Ceres by one or more space rocks from the outer asteroid belt.

A planet-size object that possibly once visited the solar system may have permanently changed our cosmic neighborhood by warping the orbits of the four outer planets, a new study suggests.

Using the gravitational pull of a well-placed planet, such as Jupiter, to slingshot a spacecraft outwards can reduce the travel time dramatically Reaching the outer planets with a spacecraft is ...

The search for dark matter, one of the greatest mysteries of the universe, has taken a surprising ... some of the most unexpected places: inside planets, asteroids, or even everyday materials ...

You might think it is just a sphere, like the rest of the planets. But Earth or any other ... Excerpted with permission from I Am the Universe: The History and Future of the Cosmos, Srijan Pal ...

Retrogrades are often misunderstood as chaotic but are actually opportunities for reflection and growth. Each type of ...