National Aeronautics and Space Administration Logo
Follow this link to skip to the main content NASA Banner
Solar System Exploration
Our Solar System: Overview
   Education   Events   Missions   News   FAQ 
   Overview   Read More   Moons   Gallery 
Series of illustrations showing the scale of Earth in comparison to our solar system, our galaxy, our local galactic group, local superclusters and the observable Universe. In a nutshell, it shows Earth and our solar system are very, very small in the great scheme of themes.
This artist's illustration shows the Earth and our solar system's place in the Universe. Image Credit: Andrew Z. Colvin

The words solar system refer to the sun and all of the objects that travel around it -- planets, natural satellites such as the moon, asteroid belt, comets, and meteoroids. Our solar system is part of a spiral galaxy known as the Milky Way. The sun, the center of our solar system, holds eight planets and countless smaller objects in its orbit.

10 Need-to-Know Things About Our Solar System:

  1. Our solar system is made up of the sun and everything that travels around it. This includes eight planets and their natural satellites such as Earth's moon; dwarf planets such as Pluto and Ceres; asteroids; comets and meteoroids.
    Button to Launch Eyes on the Solar System Interactive
    Eyes on the Solar System:
    Explore our galactic neighborhood in 3D. Image credit: NASA
  2. The sun is the center of our solar system. It contains almost all of the mass in our solar system and exerts a tremendous gravitational pull on planets and other bodies.
  3. Our solar system formed about 4.6 billion years ago.
  4. The four planets closest to the sun -- Mercury, Venus, Earth, and Mars -- are called the terrestrial planets because they have solid, rocky surfaces.
  5. Two of the outer planets beyond the orbit of Mars -- Jupiter and Saturn -- are known as gas giants; the more distant Uranus and Neptune are called ice giants.
  6. Most of the known dwarf planets exist in an icy zone beyond Neptune called the Kuiper Belt, which is also the point of origin for many comets.
  7. Many objects in our solar system have atmospheres, including planets, some dwarf planets and even a couple moons.
  8. Our solar system is located in the Orion Arm of the Milky Way Galaxy. There are most likely billions of other solar systems in our galaxy. And there are billions of galaxies in the Universe.
  9. We measure distances in our solar system by Astronomical Units (AU). One AU is equal to the distance between the sun and the Earth, which is about 150 million km (93 million miles).
  10. NASA's twin Voyager 1 and Voyager 2 spacecraft are the first spacecraft to explore the outer reaches of our solar system.

Read More About Our Solar System Blue arrow

Homework? We can help. Link to homework help for our solar system.
Just the Facts
Known to the Ancients: Mercury, Venus, Mars, Jupiter, and Saturn. These planets are visible to the naked eye and have been known since prehistoric times.

Modern: Uranus (1781), Neptune (1846) and dwarf planet, Pluto (1930) were discovered only after the invention of the telescope. It was in 2006 when Pluto was reassigned as a dwarf planet.
People Spotlight
Gerard Kuiper Gerard Kuiper
Gerard Kuiper is regarded by many as the father of modern planetary science. His theories led to the discovery of the Kuiper Belt. Read More...
Science & Technology Features
Awards and Recognition   Solar System Exploration Roadmap   Contact Us   Site Map   Print This Page
NASA Official: Kristen Erickson
Advisory: Dr. James Green, Director of Planetary Science
Outreach Manager: Alice Wessen
Curator/Editor: Phil Davis
Science Writers: Courtney O'Connor and Bill Dunford
Producer: Greg Baerg
Webmaster: David Martin
> NASA Science Mission Directorate
> Budgets, Strategic Plans and Accountability Reports
> Equal Employment Opportunity Data
   Posted Pursuant to the No Fear Act
> Information-Dissemination Policies and Inventories
> Freedom of Information Act
> Privacy Policy & Important Notices
> Inspector General Hotline
> Office of the Inspector General
> NASA Communications Policy
> NASA Advisory Council
> Open Government at NASA
Last Updated: 10 Mar 2015