How far? How big? Distance and Size in Astronomy

Need help trying to comprehend the vast distances between astronomical objects? Are you seeking to understand the relative sizes of planets, moons, asteroids, and comets? This page provides links to information, illustrations, images, animations, and interactives on Windows to the Universe about distance and size in astronomy.

Last modified April 21, 2006 by Randy Russell.

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Cool It! Game

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Large and Medium-sized Moons of Saturn

Saturn has // Call the moon count function defined in the document head print_moon_count('saturn'); moons. Many of those are tiny chunks of rock or ice only a few kilometers (miles) across. One of Saturn's...more

Medium-sized Moons of Saturn

Saturn has // Call the moon count function defined in the document head print_moon_count('saturn'); moons. Many of those are tiny chunks of rock or ice only a few kilometers (miles) across. One of Saturn's...more

The Beginning of the Solar System

Scientists believe that the solar system was formed when a cloud of gas and dust in space was disturbed, maybe by the expl osion of a nearby star (called a supernova). This explosion made waves in space...more

The Solar System

The solar system is made up of the Sun, the // Call the planets count function defined in the document head print_planet_count('planets'); planets and // Call the planets count function defined in the...more

Eris - a dwarf planet

Eris is a dwarf planet in our Solar System. Eris is a lot like Pluto, which is also a dwarf planet. Eris and Pluto are both very far from the Sun. They are both very, very cold. Eris was discovered in...more

What is a planet?

Do you know what a planet is? Guess what... astronomers are not quite sure what a planet is! Mercury, Venus, Earth, and Mars are the planets closest to the Sun. They are definitely all planets. They are...more

Orionid Meteor Shower

Meteor showers are times when you can see a lot of meteors in one night. There are several different meteor showers. Each meteor shower happens at the same time every year. There is a meteor shower in...more

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