Mars's moon Phobos is so strange that no one knows how it formed. But a forthcoming mission could solve this mystery - and a host of other puzzles connected to the solar system's deep past ...

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

This sudden void is the real kicker: it suggests that the objects comprise a distinct ... been observed in other planetary ...

NASA artist’s conception of a brown dwarf (main) and stock image of the planets in the solar system (inset). An object between 2 and 50 times the mass of Jupiter may have flown through our ...

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.

But our own Solar System's disc is relatively warped, with the orbits of its planets slightly tilted and more oval than circular. What happened to it? It's possible a heavy object fell into the mix ...

Material retrieved from the asteroid Bennu by NASA’s OSIRIS-REx spacecraft shows that all the basic building blocks of life ...

What an amateur astronomer recently took to be a newly-discovered asteroid turned out to be a Tesla Roadster voyaging through the cosmos.

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

A new study suggests that a planet-sized object may have passed through the solar system billions of years ago. Its journey could have permanently altered the orbits of the outer planets.

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.