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Solar System

Explore the planets, the Sun, the Moon, comets, meteor showers, and everything orbiting our home star.

All Uncategorized Astronomers Deep Sky Cosmology Dark matter Women Telescopes Astrophotography Fundamentals Astronomical Events Eclipses Events

What Happens If an Asteroid Hits Earth? — Illustration of NASA's DART planetary-defense mission approaching an asteroid

What Happens If an Asteroid Hits Earth?

What happens if an asteroid hits Earth? The real science of impacts, the odds, how NASA tracks and deflects threats, and what different sizes would do.

Eris: The Dwarf Planet That Demoted Pluto — Eris and its moon Dysnomia imaged by the Hubble Space Telescope

Eris: The Dwarf Planet That Demoted Pluto

Eris is the distant, icy dwarf planet whose 2005 discovery demoted Pluto. Learn about Eris, its moon Dysnomia, and why it redefined what a planet is.

Meteor Showers: A Complete Stargazer Guide — Photo by v2osk / Unsplash

Meteor Showers: A Complete Stargazer Guide

Meteor showers are the night sky's most accessible fireworks. A complete guide to when, where and how to watch the year's best meteor showers.

The Moons of the Solar System — Europa, one of the major moons of the solar system

The Moons of the Solar System

From volcanic Io to ocean-world Europa, explore the moons of the solar system — the most fascinating worlds you can chase with a backyard telescope.

The Sun: Our Star Explained — The Sun imaged in extreme ultraviolet by NASA's Solar Dynamics Observatory

The Sun: Our Star Explained

The Sun is a 4.6-billion-year-old ball of plasma anchoring the solar system. How our star works — its layers, sunspots, the solar cycle, and safe viewing.

Mercury: The Smallest Planet — Mercury, the smallest planet, in enhanced colour from MESSENGER

Mercury: The Smallest Planet

Mercury is the smallest planet and closest to the Sun. Learn Mercury's extremes of heat and cold, its cratered surface, and how to spot it from your backyard.

Mars: The Red Planet — Mars, the red planet, imaged by the Hubble Space Telescope

Mars: The Red Planet

Mars is the red planet backyard astronomers chase hardest. Learn about Mars, its oppositions, polar caps and surface detail — and how to observe it.

The Moon: Our Nearest Neighbour in Space — The full Moon showing its craters and dark maria

The Moon: Our Nearest Neighbour in Space

The Moon is Earth's only natural satellite and the best first target for any telescope. Explore its phases, seas and craters, and how to observe the Moon.

Comets: What They Are and How to Photograph Them — A comet imaged against the stars by the Hubble Space Telescope

Comets: What They Are and How to Photograph Them

Comets are icy wanderers that grow glowing heads and tails as they near the Sun. Learn what comets are, where they come from, and how to photograph them.

Asteroids and the Asteroid Belt — Asteroid Vesta, one of the largest bodies in the asteroid belt

Asteroids and the Asteroid Belt

Asteroids are rocky leftovers from the solar system's birth, most orbiting in the asteroid belt. Learn what asteroids are, their types, and why they matter.

Trans-Neptunian Objects and the Kuiper Belt — Pluto, the largest trans-Neptunian object in the Kuiper Belt

Trans-Neptunian Objects and the Kuiper Belt

Trans-Neptunian objects are icy worlds beyond Neptune in the Kuiper Belt. A guide to TNOs, dwarf planets like Pluto and Eris, and the outer solar system.

The Planets of the Solar System: A Complete Guide — Planets of the solar system montage

The Planets of the Solar System: A Complete Guide

The eight planets of the solar system, from Mercury to Neptune — explored one by one with key facts, sizes, moons, and how to see each from Earth.