Download Uranus There are no cars on the planet Uranus. Yet Uranus is

Uranus
There are no cars on the planet Uranus. Yet Uranus is
covered with a kind of smog. Smog on Earth is pollution
that comes mostly from cars that burn gasoline. Sunlight
changes fumes from the cars to smog.
Smog on Uranus comes from gases called ethane and
methane. Small amounts of these gases are part of the
atmosphere of Uranus. An atmosphere is the layer of
gases around a planet, like air on Earth. Sunlight shining
on methane and ethane makes smog. The haze of smog
around Uranus makes the planet look like a smooth,
bluish-green beach ball.
WHO DISCOVERED URANUS?
Uranus was the first planet discovered with a telescope. William
Herschel, an astronomer in England, found Uranus in 1781.
Astronomers are scientists who study things in space.
Astronomers had known about Uranus since 1690, but they did
not know Uranus was a planet. At first, they thought it was a star
or a comet. Astronomers named the planet Uranus for an
ancient Greek god of the heavens.
WHAT IS IT LIKE ON URANUS?
Uranus is a huge planet. It is the third largest planet in the solar
system, after Jupiter and Saturn. The diameter (width) of
Uranus is more than four times bigger than the diameter of
Earth.
You could not walk around on Uranus. Uranus does not have a
solid surface. The planet is made up mostly of gas. It has clouds
made of methane ice high in the atmosphere. The clouds get
thicker and thicker the farther down you go.
The thick clouds blend into a liquid ocean. Astronomers think
the ocean on Uranus is made of water and the chemicals
ammonia and methane.
THE ATMOSPHERE OF URANUS
You could not breathe on Uranus. The atmosphere there is
made mostly of hydrogen gas and helium gas. There are also
small amounts of the gases ethane and methane.
There are thick blue clouds in the atmosphere. Uranus has
some of the brightest clouds in the solar system. Strong winds
blow the clouds around. The clouds make striped patterns under
the smog.
URANUS LIES ON ITS SIDE
Uranus looks like it is spinning lying down. All planets spin. They
spin around an imaginary line called an axis. The line goes from
the north pole to the south pole. It goes from the top to the
bottom of a planet.
Most planets are tilted a bit. Earth is tilted as it spins around its
axis. But Uranus is tilted so much that it is lying on its side.
Astronomers think that something big crashed into Uranus after
it formed. The crash may have knocked Uranus onto its side.
There are weird seasons on Uranus. At times, the north pole or
the south pole faces directly toward the Sun. Each season on
Uranus is more than 20 years long!
WHAT ARE THE RINGS AND MOONS LIKE?
Astronomers have found 13 rings around Uranus. The rings go
around the equator. An equator is an imaginary line around the
middle of a planet. The rings are dark and faint. They may be
made of ice and dust.
Uranus has many moons. Astronomers believe the planet has at
least 27 moons. The 2 biggest and brightest moons are Oberon
and Titania.
The next largest moons are Umbriel and Ariel. The surfaces of
all 4 of these big moons are covered with holes called craters.
Meteorites (rocks from space) probably made the craters.
Astronomers think that these 4 moons are made of ice and rock.
Another smaller, icy moon named Miranda looks very strange.
It has a jumble of ridges. It has three weird areas shaped like
oval racetracks. There is nothing like Miranda anywhere else in
the solar system. Miranda is a very mysterious little moon.
HOW DO WE LEARN ABOUT URANUS?
Astronomers use telescopes to learn how Uranus moves across
the sky. Uranus is the seventh planet from the Sun. It orbits, or
goes around, the Sun in an oval-shaped path. Its average
distance from the Sun is a bit less than 2 billion miles (3 billion
kilometers). Uranus is so far away that it takes 84 years for the
planet to go around the Sun once!
Most of what we know about Uranus comes from a trip to the
planet by the Voyager 2 spacecraft. Voyager 2 flew past Uranus
in 1986. Voyager 2 took many pictures of the planet and its rings
and moons.
Astronomers also study pictures from the Hubble Space
Telescope. This telescope orbits high above Earth. They use
other big telescopes on Earth to study Uranus.
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