Our Moon isn’t the only moon!
No matter where you are on Earth, you can
usually look up into the night sky and see
the Moon.
Our Moon appears so big and bright because
it’s closer to Earth than any other planet
or moon.
But, our Moon isn’t the only moon out there.
That’s right!
In fact, some planets have a lot of moons.
A moon is a natural object that orbits anything
larger than itself.
Moons come in many shapes and sizes.
Our solar system has eight planets and dozens
of moons.
Almost every planet has ‘em.
Mercury and Venus—the two planets closest
to the Sun—have no moons at all.
Earth, on the other hand, has one rocky and
rather large Moon.
It’s about one-quarter the size of Earth.
Our Moon is the only other place in our solar
system where humans have set foot.
What are some of the other interesting moons
we know about?
Well, Mars has two moons named Phobos and
Deimos.
They’re dark and lumpy and at least 100
times smaller than Earth’s moon.
Jupiter has more than 70 moons!
Several of them have very unusual features.
For example, Ganymede is the largest known moon in our solar system.
You can actually see it from Earth with just a pair or binoculars.
Jupiter’s moon 
Io is covered in volcanos
And there is thought to be a giant salt water
ocean under the icy surface of Jupiter’s
moon Europa!
NASA is planning a future mission to investigate
Europa and its underground ocean.
Saturn has more than 80 moons in total.
And at least two of those are ocean moons,
too!
They are called Titan and Enceladus.
NASA’s Cassini mission discovered that the
underground ocean on Enceladus shoots jets
of icy particles from cracks in the moon’s
surface and out into space!
Uranus has more than 20 moons.
Its larger moons, like this one named Ariel,
are thought to be made of half water ice and
half rock.
Scientists have discovered more than a dozen
moons orbiting Neptune.
It’s largest moon, called Triton, has volcanoes
with icy lava flows.
Brr!
Volcanoes, underground oceans, and icy jets—what
do you think we’ll discover on moons next?
Find out more about moons at NASA Space Place.
