The solar system lost its ninth planet back when Pluto was demoted to a dwarf planet, but research might indicate that there ...

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Astronomers have picked up evidence of an Earth-sized world, distinct from the previously hypothesised Planet Nine and Planet ...

CAPE CANAVERAL, Fla. -- Scientists reported Wednesday they finally have "good evidence" for Planet X, a true ninth planet on the fringes of our solar system. The gas giant is thought to be almost as ...

In 2006, updated research led to Pluto being controversially demoted to dwarf planet status by the International Astronomical Union. The reasoning was that Pluto's location in the far-flung ...

When I was a kid, there were nine planets. Now we know of thousands! But that includes exoplanets, alien worlds that orbit alien suns. Only eight planets call our solar system home. Or there might ...

Astronomers have directly spotted a rare young planet, WISPIT 2b, still forming within the gap of a dusty ringed disk around a star like our sun—something long theorized but never observed until now.

When you buy through links on our articles, Future and its syndication partners may earn a commission. A composite image comparing the relative sizes of our solar system's known dwarf 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. When ...

The solar system is 4.54 billion years old, based on rock dating. Gas giants (Jupiter and Saturn) likely formed first. Ice giants (Uranus and Neptune) probably formed next. Rocky planets formed last, ...