Download GENERAL INFORMATION ON URANUS

GENERAL INFORMATION ON URANUS
Uranus is the seventh planet from the sun in our solar system. This huge, icy planet is covered with clouds and
is encircled by a belt of 11 rings and 22 known moons. Uranus' blue color is caused by the methane (CH4) in its
atmosphere; this molecule absorbs red light.
ROTATIONAL AXIS
Uranus' rotational axis is strongly tilted on its side (97.9°). Instead of rotating with its axis roughly
perpendicular to the plane of its orbit (like all the other planets in our Solar System), Uranus rotates on its side
(along its orbital path). This tipped rotational axis gives rise to extreme seasons on Uranus.Because of its
almost-perpendicular axis orientation, there is a debate over which of Uranus' poles is its north pole. This
debates leads to yet another: Is Uranus spinning in a retrograde orbit (like
Venus) or not (like the other planets)?
SIZE
Uranus is about 31,690 miles (51,118 km)
in diameter. This is about 4 times the
diameter of the Earth.
This gas giant is the third-largest planet in
our Solar System (after Jupiter and Saturn).
MASS AND GRAVITY
Uranus' mass is about 8.68 x 1025 kg. This is about 14 times the mass of the Earth. The gravity on Uranus is only
91% of the gravity on Earth. This is because it is such a large planet (and the gravitational force a planet exerts
upon an object at the planet's surface is proportional to its mass and to the inverse of its radius squared).
A 100-pound person on Uranus would weigh 91 pounds.
LENGTH OF A DAY AND YEAR ON URANUS
Each day on Uranus takes 17.9 Earth hours. A year on Uranus takes 84.07 Earth years; it takes 84.07 Earth
years for Uranus to orbit the sun once.
URANUS' ORBIT AND DISTANCE FROM THE SUN
Uranus is over 19 times as far from the Sun as the Earth is; it
averages 19.18 A.U.
At aphelion (the farthest point in its solar orbit) it is 1,850,000,000
miles (3,003,000,000 km) from the Sun. At perihelion (the closest point
its solar orbit) it is 1,700,000,000 miles (2,739,000,000 km) from the
Sun.
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TEMPERATURE
The mean temperature on the surface of Uranus' cloud layer is -350°F (59 K). Uranus radiates very little heat in
comparison with the other gas giants, Jupiter, Saturn and Neptune).
PLANETARY COMPOSITION AND ATMOSPHERE
Uranus is a frozen, gaseous planet with a molten core. Uranus' atmosphere consists of 83% hydrogen, 15%
helium and 2% methane.
RINGS
Uranus has a belt of 11 faint, narrow rings composed of rock and dust. They circle
Uranus is very elliptical orbits. These rings are only a fraction of the size of Saturn's
rings, and were only discovered in 1977.
Uranus and its rings
photographed by an infrared
camera.
MOONS
Uranus has 5 large moons (2 were
discovered by Wm. Herschel in 1781, 2
were discovered by Wm. Lassell in
and many small moons (which were
1851, and one by G. Kuiper in 1948)
discovered much later).
For more information on Uranus'
moons, click here.
Oberon, the largest moon of
Uranus. Photo taken by
NASA's Voyager mission in
1986.
DISCOVERY OF URANUS
Uranus was discovered by the British astronomer William Herschel on March 13, 1781. Herschel also
discovered two of the moons of Uranus (Titania and Oberon) and some of the moons of Saturn.
URANUS-EARTH COMPARISON
URANUS' NAME AND SYMBOL
This planet was originally named in 1781 by the British astronomer William
Herschel - he called it Georgium Sidus (meaning "the Georgian planet") to honor
the King George III of England. The name was later changed to Uranus, the
ancient mythological god of the sky, Ouranos. The name Uranus was suggested
by the German astronomer Johann Elert Bode.
This is the symbol of the planet
Uranus.
SPACECRAFT VISITS
Uranus has been visited by NASA's Voyager 2, whose closest approach was on January 24, 1986.
Uranus
1. Uranus is the third-largest planet in the Solar System. Is its diameter 4-times, 14-times, or 24-times bigger
than the Earth?_________________
2. Would a person weigh more, less, or the same on Uranus as they would on Earth? ___________________
3. How long does it take Uranus to revolve around the Sun (one Uranus year)?_______________________
4. Uranus' axis is very tilted; what does this lead to? _______________________
5. What is the major component of Uranus' atmosphere? ___________________
6. Does Uranus have a solid surface? _______________________
7. What is the longest period of daylight on Uranus? ______________________
8. Does Uranus have rings circling it? _______________________
9. How many moons does Uranus have? ______________________
10. When was Uranus discovered? ______________________
Fill in the blanks below.
Word Bank:
Herschel
rings
Jupiter
seasons
1977
gravity
axis
heat
blue
91
moons
Sun
mass
gas giant
Greek
Uranus is the seventh planet from the Sun in our Solar System. This huge, icy gas-giant is covered with clouds and is
encircled by a belt of 11 faint rings and 18 ___________________________. Uranus' ___________________________
color is caused by the methane (CH4) in its atmosphere; this molecule absorbs red light. Uranus was discovered by the
British astronomer William ___________________________ on March 13, 1781. It was named for the ancient
___________________________ god of the sky.
Uranus' 11 faint, narrow ___________________________ are composed of rock and dust. They circle Uranus is very
elliptical orbits. These rings are only a fraction of the size of Saturn's rings, and were only discovered in
_______________________.
Uranus is about 31,690 miles (51,118 km) in diameter. This is about 4 times the diameter of the Earth. This gas giant is
the third-largest planet in our Solar System (after ___________________________ and Saturn).
Each day on Uranus takes 17.9 Earth hours. A year on Uranus takes 84.07 Earth years; it takes 84.07 Earth years for
Uranus to orbit the ___________________________ once.
Uranus' rotational axis is strongly tilted on its side (97.9°). Instead of rotating with its axis roughly perpendicular to the
plane of its orbit (like all the other planets in our Solar System), Uranus rotates on its side (along its orbital path). This
tipped rotational ___________________________ gives rise to extreme ___________________________ on Uranus. The
mean temperature on the surface of Uranus' cloud layer is -350°F (59 K). Uranus radiates very little
___________________________ in comparison with the other ___________________________ planets.
Uranus' ___________________________ is about 8.68 x 1025 kg. This is about 14 times the mass of the Earth, but the
gravity on Uranus is only 91% of the ___________________________ on Earth. This is because it is such a large planet
(and the gravitational force a planet exerts upon an object at the planet's surface is proportional to its mass and to the
inverse of its radius squared). A 100-pound person on Uranus would weigh ________________________ pounds.