A massive interstellar object passing through our solar system during its formative years likely altered the orbits of planets into trajectories observed today, a new study says. Interactions with ...

Which way is ‘down’ has a different answer depending on where you are on Earth, in the solar system, in our galaxy and beyond ...

A new study suggests that a close encounter with a massive interstellar object, possibly eight times the mass of Jupiter, may have significantly altered the orbits of the four outer planets in our ...

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. When ...

The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have dubbed ...