The solar system has one star, eight planets, five dwarf planets, at least 290 moons, more than 1.3 million asteroids, and about 3,900 comets.
It is located in an outer spiral arm of the Milky Way galaxy called the Orion Arm, or Orion Spur. Our solar system orbits the center of the galaxy at about 515,000 mph (828,000 kph). It takes about 230 million years to complete one orbit around the galactic center.
We call it the solar system because it is made up of our star, the Sun, and everything bound to it by gravity – the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune; dwarf planets Pluto, Ceres, Makemake, Haumea, and Eris – along with hundreds of moons; and millions of asteroids, comets, and meteoroids.
Our solar system is the only one we know of that has a planet that supports life. So far, we only know of life on Earth, but we’re looking for life on other worlds.
Our solar system has a star, eight planets, five dwarf planets, and thousands of asteroids, and comets.
Meet Me in the Orion Arm
Our solar system orbits the center of the Milky Way galaxy. We’re in one of the galaxy’s four spiral arms.
A Long Way Around
It takes our solar system about 230 million years to complete one orbit around the galactic center.
Spiraling Through Space
There are three general kinds of galaxies: elliptical, irregular, and spiral. The Milky Way is a spiral galaxy.
Room to Breathe
Our solar system has no atmosphere. But it has many worlds – including Earth – with many kinds of atmospheres.
Getting Out There
More than 300 robotic spacecraft have left Earth's orbit, and 24 U.S. astronauts have traveled to the Moon.
Life as We Know It
So far, Earth is the only place we've found life in our solar system, but we’re looking.
Only two spacecraft have reached interstellar space, the space between stars. Three other spacecraft have achieved enough velocity to eventually travel beyond the boundaries of our solar system.
- Voyager 1 went interstellar in 2012 and Voyager 2 joined it in 2018. Both spacecraft, launched in 1977, are still in communication with Earth.
- NASA's New Horizons spacecraft is currently exploring an icy region beyond Neptune called the Kuiper Belt. It eventually will leave our solar system.
- Pioneer 10 and Pioneer 11 also will ultimately travel silently among the stars toward the galactic core. The spacecraft used up their power supplies decades ago.