Solar System Exploration: Planet Selector: Pluto

PLANET SELECTOR

ABOUT PLUTO

Tiny, cold and incredibly distant, Pluto was discovered in 1930 and long considered to be the ninth planet in the solar system. But as of August 24, 2006, Pluto has been reclassified by the International Astronomical Union as a "dwarf planet." Pluto is also known as a Kuiper Belt Object (KBO) or Trans-Neptunian Object (TNO).
Read More About Pluto >>

Featured Mission: New Horizons
NASA's New Horizons will be the first spacecraft to visit Pluto. The spacecraft's 9 1/2 year journey to the farthest planet begins in January 2006.
Read More About New Horizons >>

VITAL STATISTICS

Average Distance from Sun:	5,906,376,200 km (3,670,044,979 miles)
Diameter:	2,400 km (1,491 miles)
Volume:	0.005 x Earth's
Mass:	13,140,000,000,000,000,000,000 kg (0.0022 x Earth's)
Length of Day:	6.394 Earth days
Length of Year:	248 Earth years
Known Moons:	1

SIZE & DISTANCE

If the Sun was as tall as a typical front door, Earth would be the size of a nickel - and Pluto would be about as big as the head of a pin.

Average Distance from the Sun: 5,906,376,200 km (39.49 A.U.)

EXTREME SPACE

Long, Strange Trip
Pluto's trek around our Sun takes 248 years - so long it still hasn't finished one orbit since it was discovered in 1930. The planet's orbit is so elliptical - picture a squashed circle - its distance from the Sun varies more than 2,700,000,000 km (1,900,000,000 miles).

Deep Freeze
Pluto is so cold even the air can freeze and fall to the ground like snow. The planet's average temperature is about minus 233!degree; C ( minus 387!degree; F). The coldest spot on Earth gets down to minus 89° C (-128° F).

Distance Runner
Even though it will travel at speeds 30 times greater than the fastest fighter jet, NASA's New Horizons spacecraft will still take 9 1/2 years to get to Pluto. If you could somehow fly an airliner to Pluto, the trip would take more than 800 years.

Bring a Flashlight
High noon on Pluto would look a lot like a moonlit night here on Earth. The sunlight that reaches Pluto is about 1,000 times dimmer than what we see here on Earth and provides little warmth.

Camera-Shy Planet
Pluto is so small and so far from Earth it is currently impossible to get good pictures. Even our most powerful telescopes show little more than fuzzy blobs when pointed across billions of kilometers at Pluto and Charon.

Faint Discovery
There are millions of stars brighter than Pluto in the night sky, but observant astronomer Clyde Tombaugh caught a faint image - light equal to a candle seen at a distance of 480 km (300 miles) - on a photographic plate that turned out to be Pluto. He had discovered the mysterious ninth planet.

TIMELINE

1930 - American astronomer Clyde Tombaugh discovers Pluto.

1951 - Dutch astronomer Gerald Kuiper predicts the existence of a belt of icy objects beyond the orbit of Neptune. The region will later be named the Kuiper Belt.

1977-1999 - Pluto's lopsided orbit brings it slightly closer to the Sun than Neptune. It will be at least 230 years before Pluto gets another 20-year stint as the eighth planet.

1978 - American astronomers James Christy and Robert Harrington discover Pluto's moon, Charon.

1992 - After five years of searching, astronomers David Jewitt and Jane Luu confirm the discovery of the first Kuiper Belt Object, 1992 QB1.

2002-now - Pluto has three known moons, Hydra and Nix, as well as its companion moon, Charon. At about 1,186 km (737 miles), Charon's diameter is a little more than half of Pluto's.

SLIDE SHOW

Pluto
Pluto and Charon
Pluto's Surface
Image Comparison
Artist's Impression of Pluto
Charon Discovery Image
Kuiper Belt Object Quaoar
Quaoar Size Comparison
First Kuiper Belt Object
Another Kuiper Belt Object
Possible New Moons Orbiting Pluto

MOONS

Pluto has three known moons, Hydra and Nix, as well as its companion moon, Charon. At about 1,186 km (737 miles), Charon's diameter is a little more than half of Pluto's.