Astronomy

Study of celestial objects, space, and the physical universe.

Basic Concepts

The Solar System

Exploring Our Cosmic Neighborhood

The Solar System is the collection of planets, moons, asteroids, comets, and the Sun that makes up our home in space. The Sun sits at the center, holding everything together with its gravity. The eight main planets—including Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune—orbit the Sun in elliptical paths.

What Else Is Out There?

Besides the planets, our Solar System is filled with fascinating objects like asteroids in the asteroid belt (between Mars and Jupiter), icy comets that zip through space, and dozens of moons orbiting planets. Some moons, like Jupiter’s Ganymede or Saturn’s Titan, are even bigger than some planets!

How Do We Study the Solar System?

Astronomers use telescopes, robotic spacecraft, and even landers and rovers to explore our Solar System. These tools help us learn about the formation of planets, the potential for life elsewhere, and the history of Earth.

Why Does It Matter?

Understanding the Solar System helps us figure out where Earth fits in the universe, and it’s key to exploring beyond our planet.

Examples

  • Earth orbits the Sun once every 365 days, creating our year.

  • NASA’s Perseverance rover is currently exploring Mars.

In a Nutshell

The Solar System is our local group of planets, moons, and other objects orbiting the Sun.

Key Terms

Planet
A large object that orbits a star and does not produce its own light.
Asteroid
A small, rocky object orbiting the Sun, mostly found in the asteroid belt.
Comet
An icy object that releases gas and dust, forming a glowing tail when near the Sun.