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.

All seven of the other planets in our solar system are about to become visible at once in a great planetary alignment – ...

The eight major planets of our Solar System orbit the Sun in the same flat plane, and all at different speeds. Mercury, the closest planet to the Sun, completes an orbit – a year for the planet ...

Simpson and Chen ran mathematical models looking at how differently sized Earth-like worlds would have affected the rest of our Solar System. The planet sizes tested were 1 percent of Earth's mass, ...

"We are the first mission to be able to track space weather events in three dimensions routinely across the solar system." ...

For the first time, astronomers have imaged dozens of belts around nearby stars where comets and tiny pebbles within them are ...

Stargazers will be treated to a rare alignment of seven planets on 28 February when Mercury joins six other planets that are already visible in the night sky. Here's why it matters to scientists.

Mercury takes only 88 Earth days to orbit the sun.

An asteroid that orbited near Earth for a few months as a mini-moon may be a chunk of the moon that was blasted off by an impact thousands of years ago.

Add to this the fact that an interstellar object is on a different orbit to the solar system, so it’s already coming in hot—with some appreciable fraction of the galactic orbital ...

Why is Pluto no longer a planet? Discover the real reason behind Pluto’s reclassification as a dwarf planet and the science that led to this change.