Pluto was discovered in 1930 and named after the Roman god of
the dark underworld. It may have received this name because it’s always in darkness
since it is so far from the Sun
Pluto was once known as the ninth planet and the furthest from the Sun.
It was also the smallest planet.
On August 24, 2006 Pluto's status as a planet was changed to a "dwarf planet".
We do not know much about Pluto because it is so far from Earth.
It looks like a fuzzy blob even with the most powerful telescopes.
It is over 5.9 billion km (three and a half billion miles) from the Sun.
The light from the Sun looks very dim from Pluto. (note the sun in the image below)
"Artist’s impression of how the surface of Pluto might look.
The image shows patches of pure methane on the surface."
credit: ESO (European Organisation
for Astronomical Research in the Southern Hemisphere)
Pluto is smaller than Earth's moon and has a moon named Charon which is about half the size of Pluto.
Two additional small moons (Nix and Hydra) were spotted by the Hubble Space
Telescope in 2005.
Pluto and moons (Charon, Nix and Hydra) taken Feb.16,2006
Credit: NASA, ESA, H. Weaver (JHU/APL), A. Stern (SwRI),
and the HST Pluto Companion Search Team
Pluto is so cold that air can freeze and fall to the ground like snow.
Its surface is frozen nitrogen, methane, and carbon dioxide.
The interior is probably a rocky core surrounded by ice.
There are dark and bright regions across its surface.
Pluto rotates once every 6.4 days and spins the opposite
direction of most other planets. Like Uranus, Pluto rotates on its side.
It takes 248 Earth years to orbit the Sun.
From 1979 to 1999 Pluto and Neptune crossed orbits
and Pluto was closer to the Sun than Neptune.
The New Horizons Pluto-Kuiper Belt mission was
launched in January 2006 and should reach Pluto in July 2015.
It takes nine and a half years for the spacecraft to reach Pluto. An airliner would take more
than 800 years to get to Pluto!
artist's concept of New Horizons spacecraft
approaching Pluto and its moons in 2015.
Credit: Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute (JHUAPL/SwRI)
