Astronomy Picture of the Day |
APOD: 2001 August 26 - Uranus: The Tilted Planet
Explanation:
Uranus is the third largest planet in our
Solar System after
Jupiter and
Saturn.
Uranus
is composed mostly of rock and ices,
but with a thick
hydrogen and
helium atmosphere.
The blue hue of Uranus' atmosphere arises from the small amount of
methane which preferentially absorbs red light.
This picture was snapped by the
Voyager 2 spacecraft in 1986 -
the only spacecraft ever to visit Uranus.
Uranus has many
moons and a
ring system.
Uranus, like
Venus, has a rotation axis that
is greatly tilted and sometimes points near the Sun.
It remains an astronomical mystery why
Uranus' axis is so tilted.
Uranus and
Neptune are quite similar:
Uranus is slightly larger but less massive.
APOD: 1997 November 26 - Uranian Moons, Rings, And Clouds
Explanation:
The giant planet Uranus is faint and featureless when
viewed in visible light.
But
this pair of
near-infrared mosaics from the
Hubble Space Telescope's
NICMOS camera reveals
moons, rings, and clouds of
this distant gas planet.
The color coded images highlight different atmospheric layers -
blue represents the deepest layers while the highest
cloud features have a reddish tinge.
Racing around the planet, high, bright clouds are seen to
move substantially between the two pictures taken only ninety minutes apart.
Ring systems are a common to
the solar system's giant planets.
Here the
main Uranian ring seems to vary in width
and is clearly brightest near the top.
The eight specks beyond the ring system are
small Uranian moons which
also show counter-clockwise motion
over ninety minutes as traced by the
arrows on the right hand image.
APOD: 1996 April 30 - Uranus' Ring System
Explanation:
The rings of
Uranus
are thin, narrow, and dark compared to other planetary
ring systems. Brightened artificially by computer, the ring particles
reflect as little light as charcoal, although they are really made of ice
chucks darkened by rock.
This false-color,
infrared picture from the
Hubble Space Telescope taken in
July 1995 shows the rings in conjunction to the planet. The
infrared
light allows one to see detail in different layers of
Uranus' atmosphere,
which has been digitally enhanced with false color.
Three other planets in our
Solar System are known to have rings:
Jupiter,
Saturn, and
Neptune.
Four of
Uranus' moons are visible outside the ring plane. The
rings of
Uranus were discovered from ground-based observations
in 1977.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
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NASA Official: Jay Norris.
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EUD at
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GSFC
& Michigan Tech. U.