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

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

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 ...

New research suggests that a massive, unidentified object might have passed through our Solar System billions of years ago, ...

A new study claims it is possible an "alien visitor" could have warped our solar system during its earliest years.

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 ...

Beyond Neptune lies the Kuiper Belt, a vast expanse of icy bodies that may hold clues to the solar system’s formation. These ...

A new study suggests that a planet-sized object may have passed through the solar system billions of years ago.

Michigan State University and NASA researchers discover seven dark comets that reveal new solar system secrets.

When you first learned about the Solar System, you probably saw diagrams that made it look orderly, with planets arranged in ...

Two new studies show a briny, carbon-rich environment on the parent body of the Bennu asteroid was suitable for assembling ...

Further simulations on flybys into the inner Solar System revealed one of our own planets might be flung out of the ballpark ...