Astronomy Picture of the Day |
APOD: 1999 February 13 - Pluto: The Frozen Planet
Explanation:
This portrait of Pluto and its companion
Charon was taken by the Hubble Space Telescope in 1994.
Pluto is usually the most distant planet from the
Sun but because of its
eccentric orbit Pluto crossed inside
of Neptune's orbit in 1979.
On Thursday, February 11th, it crossed back out, recovering
its status as
the most distant of
nine planets.
Pluto is
still considered to be a planet, although very little
is known about it compared to other planets.
Pluto is smaller than any
other planet and even smaller than
several other planet's moons.
Pluto is probably composed of frozen rock and ice,
much like Neptune's moon Triton.
Pluto has not yet been
visited by a spacecraft, but a
mission is being planned for the next decade.
APOD: 2001 October 18 - Pluto: New Horizons
Explanation:
Pluto's
horizon spans the foreground in this artist's vision,
gazing sunward across that distant and
not yet explored world.
Titled New Horizons, the painting also
depicts Pluto's
companion, Charon, as a darkened, ghostly apparition with
a luminous
crescent
against a starry background.
Beyond
Charon,
the diminished Sun is immersed in
a flattened cloud of zodiacal dust.
Here, Pluto's ruddy colors are based on existing
astronomical
observations while imagined but
scientifically tenable details
provided by the artist include high atmospheric cirrus and
dark plumes from surface vents, in analogy to Neptune's large moon
Triton
explored by the
Voyager
2 spacecraft in 1989.
Craters suggest bombardment by
Kuiper
Belt objects, a newly understood
population of
outer solar system bodies likely
related to the
Pluto-Charon system.
NASA is now considering a future robotic reconnaissance
mission
to Pluto-Charon and the Kuiper Belt which could reach the distant
worlds late in the next decade.
APOD: 2006 June 24 - Nix and Hydra
Explanation:
Discovered in mid-2005,
Pluto's
small moons were
provisionally designated
S/2005 P1 and S/2005 P2.
They have now been officially
christened Nix and Hydra.
Compared to Pluto and its
large moon Charon, at 2,360 and 1,210 kilometers in diameter
respectively, Nix (inner moon) and Hydra (outer moon) are tiny,
estimated to be only 40 to 160 kilometers across.
Pluto and Charon are bright enough to create
diffraction spikes
in this Hubble Space Telescope image, but
Nix and Hydra are
some 5,000 times fainter than Pluto and
appear only as small points of light.
Still, their new names are appropriate for the distant
Pluto system.
In mythology,
Nix was
the goddess of darkness and night and
the mother of Charon,
while Hydra
was a nine headed monster
and is now orbiting the solar system's ninth planet.
Of course Nix and Hydra also share initials with
the pluto-bound spacecraft
New Horizons.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings, and
Disclaimers
NASA Official: Jay Norris.
Specific rights apply.
A service of:
EUD at
NASA /
GSFC
& Michigan Tech. U.