Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously ...

The newly identified cluster of Kuiper Belt objects lies about 4 billion miles from the Sun, offering fresh clues about how ...

Planet Y is the latest in a series of hypothetical solar system planets that scientists have proposed in recent years, all with slightly different characteristics but collectively believed to be ...

Jupiter is already the biggest planet by far in our solar system, but new research suggests it was somehow once even larger than it is now. Twice as large, in fact. To put that into context, those ...

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 ...

AMES, Iowa – Using data from NASA’s Kepler space telescope, an international team of astronomers has discovered a distant planetary system featuring multiple planets orbiting at a severe tilt to their ...

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 ...