Solar System vs. Galaxy vs. Universe!

What is the difference between the terms: Solar System, Galaxy, and Universe?

Answer: Basically SIZE is the biggest distinction.

Here are some definitions from a dictionary:

Solar System: Consists of the Sun, and everything bound to it by gravity. This includes the 8 planets and their moons, the asteroids, the dwarf planets, all the Kuiper belt objects, the meteoroids, comets and interplanetary dust.

Galaxy: large system of stars held together by mutual gravitation and isolated from similar systems by vast regions of space. The Milky Way measures about 100,000 light-years across, and is thought to contain 200 billion stars.

Universe: the totality of known or supposed objects and phenomena throughout space; the cosmos; macrocosm.

So to sum it up:

  • We live on planet Earth which is part of our local Solar System.
  • Our Solar System includes the Sun and everything that orbits the Sun.
  • Our Sun, is just one Star in the Milky Way Galaxy.
  • The Milky Way Galaxy is just one Galaxy in the Universe.


  • Find out how many Galaxies are in the Universe.
  • Look at super neat photos of Galaxies.
  • Become a galaxy hunter from the comfort of your own computer!

Highly Recommended:
Check out this brand new book by Terence Dickinson! This book has an incredible collection of hubble photos and interesting descriptions in over 300 pages!!!

Hubble's Universe: Greatest Discoveries and Latest Images

Never Stop Exploring!!!