NASA leads the nation on a great journey of discovery, seeking new knowledge and understanding of our planet Earth, our Sun and solar system, and the universe out to its farthest reaches and back to its earliest moments of existence. NASA recognizes the scientists and engineers who utilize science data, are at the center of it all.
The solar system has one star, eight planets, five officially recognized 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.
Mercury has a thin exosphere.
Mercury can't support life as we know it.
A year on Mercury is 88 Earth days.
Sunlight is 11 times brighter on Mercury.
Although it's similar in structure and size to Earth, Venus has a thick atmosphere that traps heat in
a runaway
greenhouse effect, making it the hottest planet in our solar system.
Venus is a cloud-swaddled planet named for a love goddess, and often called Earth’s twin. But pull
up
a
bit closer, and
Venus turns hellish. Our nearest planetary neighbor, the second planet from the Sun, has a surface
hot
enough to melt
lead. The atmosphere is so thick that, from the surface, the
In some ways it is more an opposite of Earth than a twin: Venus spins backward, has a day longer
than
its year, andgit config --global user.name
lacks any semblance of seasons. It might once have been a habitable ocean world, like Earth, but
that
was at least a
billion years ago. A runaway greenhouse effect turned all surface water into vapor, which then
leaked
slowly into space.
The present-day surface of volcanic rock is blasted by high temperatures and pressures.
Earth is the third planet from the Sun, and the only place we know of so far that’s inhabited by living things. It's also the only planet in our solar system with liquid water on the surface.
With a radius of 43,440.7 miles (69,911 kilometers), Jupiter is 11 times wider than Earth. If Earth were the size of a nickel, Jupiter would be about as big as a basketball.
From an average distance of 484 million miles (778 million kilometers), Jupiter is 5.2 astronomical units away from the Sun. One astronomical unit (abbreviated as AU), is the distance from the Sun to Earth. From this distance, it takes Sunlight 43 minutes to travel from the Sun to Jupiter.
Jupiter Facts Jupiter is the fifth planet from our Sun and is, by far, the largest planet in the solar system – more than twice as massive as all the other planets combined.
Uranus is a very cold and windy planet. It is surrounded by faint rings, and more than two dozen
small moons as it
rotates at a nearly 90-degree angle from the plane of its orbit. This unique tilt makes Uranus
appear to spin on its
side.
Only one spacecraft has explored the ice giant up close, NASA's Voyager 2. In January 1986, Voyager
2 made a close
approach to Uranus, snapping images of the planet and some its moons. A new mission to Uranus was
one of the highest
priority objectives outlined in the Planetary Science and Astrobiology Decadal Survey 2023-2032. The
possibility of a
flagship mission to Uranus will be a focus of planetary science at NASA in the years to come.
The planet’s rich blue color comes from methane in its atmosphere, which absorbs red wavelengths of light, but allows blue ones to be reflected back into space.
Voyager 2 is the only spacecraft to
visit Neptune.
Pluto and other dwarf planets are a lot like regular planets. So what’s the big difference? The International Astronomical Union (IAU), a world organization of astronomers, came up with the definition of a planet in 2006. According to the IAU, a planet must do three things:
