This rendering suggests how
Pluto, on the right, might appear from a position high above its equator. Beyond Pluto and to the
left is Pluto's largest satellite Charon. Charon's dark, "anti-sun" side is
softly illuminated by sunlight reflecting off of Pluto's surface. This rendering also illustrates
Pluto's steep rotational inclination to the ecliptic: the bright star
between Pluto and Charon is Polaris, the "north star," which lies directly
over the Earth's north pole.
The dwarf planet Pluto was discovered in 1930
by the American astronomer Clyde Tombaugh during a systematic search for a planet
that was predicted to lie beyond
Neptune. As it turned out,
the calculations that led to Pluto's prediction were wrong, but Tombaugh
happened upon Pluto anyway. Pluto's satellite Charon was discovered in 1978,
and in 2005 two additional--and diminutive--satellites, Nix and Hydra, were
discovered with the Hubble Space Telescope.
Pluto is probably made up of 70%
rock and 30% water ice, much like Neptune's satellite Triton. Pluto's surface is believed to be
host to frozen nitrogen, carbon monoxide and methane.