A Blue-Green World

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A Blue-Green World
Uranus is the third largest planet after Jupiter
and Saturn. Uranus has 21 moons and small, dusty
rings. Voyager 2 acquired this view of the
seventh planet while departing the Uranian system
in late January 1986. This image looks at the
planet approximately along its rotational pole.
Voyager 2 image of Uranus, 1986 (ImageNASA)
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A Blue-Green World
Uranus has a thick hydrogen-methane atmosphere.
Methane causes the planets blue-green color.
Some astronomers call Uranus and Neptune ice
giants because most of their mass is ice and
some rocky material. It appears that Uranus
does not have a rocky core like Jupiter and
Saturn but rather that its material is more or
less uniformly distributed.
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Hubbles View
This image, taken by Hubble, clearly shows Uranus
and its rings. Uranus rings are smaller and
dustier than those of Saturn, and will eventually
dissipate.
Image NASA
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Deep exposure of Uranus taken with the Hubble
Space Telescope reveal two small moons and two
faint rings.  All orbit outside of Uranus's
previously known (main) ring system, but interior
to the large, classical moons.
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Dusty Rings
This image reveals many broad lanes of dust
surrounding the 9 main rings of Uranus. It was
taken by Voyager 2 looking back toward the sun
through the ring system.
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Tipsy?
Uranus moves around the Sun with its rotation
axis is perpendicular to its orbit around the
sun. It is thought that a planet-sized body hit
Uranus early in its history, tipping it over.
Because of this, Uranus seasons last over 20
years!
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Earth
Uranus
Distance from Sun 1.7 Billion Miles 93 Million Miles
Diameter 32,000 Miles 7926 Miles
Length of Year 84 Earth Years 365.25 Days
Length of Day 17.24 hours 23 hours 56 minutes
Gravity .89 that of Earth 2.66 times that of Mars
Temperature Average -319 degrees F Average 57 degrees F
Number of Moons 27 1
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Georges Star

• Uranus was discovered by William Herschel, the
  British royal astronomer, in 1781.
• Herschel thought the planet was a comet at first!
  
• He tried to name it Georges Star after King
  George.

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God of the Sky
The name "Uranus" was eventually proposed in
order to conform with the other planetary names
from classical mythology. The name didn't come
into common use until 1850. To the ancient
Greeks, Uranus was god of the sky and heavens.
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Missions
Only one spacecraft has visited Uranus. On Jan.
24, 1986 Voyager 2 passed within 50,600
miles. Voyager 2 radioed images and scientific
data on the planet, its moons, rings, atmosphere,
interior and the magnetic environment surrounding
Uranus.
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Uranus Moons
Miranda
Ariel
Oberon
Titania
Umbriel
Uranus has 5 medium-sized moons and 21 smaller
moons. The five main satellites are Miranda,
Ariel, Umbriel, Tatania and Oberon.
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Miranda
Uranus moon Miranda has a strange fractured
appearance, as if it was shattered then put back
together. The high cliffs and winding valleys
of the moon may indicate that Miranda was larger
in the past and shrank to its current size.
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Titania
Picture of Titania taken by Voyager 2. Titania is
1600 kilometers in diameter.
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An artists view, this montage of images of the
Uranian system was prepared from an assemblage of
images taken by the Voyager 2 spacecraft during
its Uranus encounter in January 1986.