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

Does our Solar System have 9 planets or only 8? Astronomers have gone back and forth on that a lot, with Pluto now being classified as a dwarf planet. However, out beyond Neptune there could be ...

Although the occurrence climaxed on Jan. 21 with a conjunction—close alignment—of Saturn and Mercury, the planetary parade ...

The formation of our solar system from a singular nebula raises an intriguing question: why did each planet develop with a ...

All of our solar system’s planets are lining up to parade through the night sky at once. This extraordinary celestial event will see the sky scattered with seven visible planets in what is known ...

Stargazers will be treated to a rare alignment of seven planets on 28 February when Mercury joins six other planets that are already visible in the night sky. Here's why it matters to scientists.

Scientists believe that two asteroids might be fragments of long-lost "planetary embryos" from the early solar system.

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.

To better understand why the planets have variable compositions ... formation of the gas and ice giants in the outer solar system. This first-order model of planetary growth in the solar nebula ...

Take advantage of a special 6-7 planet alignment from Earth's perspective. Planets 'line up' in the skies over California in February.

Canadian astronomers have taken an extraordinary step in understanding how planets are born, using the James Webb Space ...