Neptune is the eighth, or next to last, planet in
our solar system. It is located in between Uranus and Pluto, and is a very
long way away from the Sun. Its average distance from the Sun is
almost 2.8 billion (2,800,000,000) miles, or over
thirty times the distance from Earth to the Sun. The orbit, or path,
Neptune follows around the Sun is almost a perfect circle. The closest
Neptune gets to the Sun is about 2.7 billion miles, and the furthest
away it gets is a little over 2.8 billion miles. At this distance, our
Sun is just another bright light in Neptune's sky.
Since Neptune is so far away from the Sun, one of its years, which is
the amount of time it takes for the planet to go around, or orbit, the
Sun once is a very long time. A year on Neptune lasts for 165 of our
Earth years! A day on Neptune, though, is shorter than a day here on
Earth. The gas planet spins, or rotates, once every sixteen hours.
- Can I See It?
-
You can see Neptune, but you will need at least a pair of binoculars,
and probably a telescope. Neptune is no larger than Uranus and is much
further away, so it will be even harder to see than the blue-green
planet. If you have dark skies and a good view to the southern
horizon, you may be able to pick it out with your binoculars.
- How Big Is It?
-
Neptune is about 30 thousand miles in diameter, about four times the
size of Earth, which is about 7,600 miles in diameter. Neptune and
Uranus are almost the same size, but both seem tiny in comparison to
mighty Jupiter, which is almost three times as large as either of
them.
- Does It Have Rings?
-
All the gas planets in our solar system have rings, and Neptune is no
exception. The Voyager space mission sent pictures to prove it. The
rings of Neptune are made up of fairly small, very dark clumps of
rock. Scientists believe that most of these clumps are about the size
of a compact car. There is also a large amount of dust in the rings.
Even though the rings are very faint, they still had a surprise for
us. One of the rings has a twist in it!
- How Many Moons Does It Have?
-
Neptune has eight moons that we know about and there may be more.
There are only two that we can see from Earth. One of them is Triton,
in the picture at top right. The family of moons surrounding Neptune
is unusual because Triton, the largest, is over 1,600 miles in
diameter and the rest of them are tiny, some as small as twenty miles
in diameter.
Almost all of Neptune's eight moons are too small to see from
Earth, so what little we do know about them came from the Voyager
space mission. Voyager took this picture of Proteus (center right) as
it flew by Neptune on its way out of the solar system.
Triton was the last solid object Voyager would see before it left
our solar system. Saving the one of its best discoveries for last, the
spacecraft sent back pictures of nitrogen "geysers" erupting
on Triton's surface. When you click on the image at bottom right, you
will be able to see the plumes in the larger picture.
- How Did It Get Its Name?
-
Neptune is named for the Roman god of the sea, but even more
interesting is the fact that astronomers were actually looking for it.
After William Herschel discovered Uranus, astronomers noticed that its
orbit, or path, didn't seem to obey the laws of physics. Something was
making Uranus move in unexpected ways. Astronomers decided that there
must be another planet making Uranus move and then calculated where
the new planet might be. Astronomers Galle and d'Arrest discovered
Neptune on September 23, 1846.
- What Is It Made Of?
- Neptune has a small central core, or ball, made of up melted rock.
Above the rocky center, the planet is covered by extremely cold water,
which eventually changes into the top layer of hydrogen and helium,
with a little methane mixed in. The methane is what gives Neptune its
color.
- What's It Like On The Surface?
- Since Neptune is a gas planet, it does not have a solid surface like
we do here on Earth. In spite of this, Neptune has some of the most
unusual "weather" in the solar system. The winds on Neptune
can blow as fast as twelve hundred miles per hour at the planet's
equator! The clouds that you see in some of the pictures above are
actually frozen water.
|