The Rise and Fall of America’s Favorite Planet The Pluto Files By Neil Degrasse Tyson

He considered naming the planet Percival, after Percival Lowell. February 18, 1930 Pluto was discovered by Clyde W. Tombaugh, an amateur astronomer from Illinois at Arizona’s Lowell Observatory. He considered naming the planet Percival, after Percival Lowell.

After all, we once called the planet Uranas “Georgium Sidus” after the English King George. Planets were traditionally named for Greek mythological characters. Uranas was the Roman god of the sky and husband of mother earth.

The name Pluto was suggested in 1930 by an eleven year old English school girl, Venetia Burney.

Pluto was already the name of a laxative mineral water.

Pluto became the name of the Disney dog in 1931. Pluto the Pup appeared in a Mickey Mouse cartoon.

Pluto was the god of the dead and underworld in the realm of darkness.

Uranium was already part of the periodic table when Plutonium was added in 1945.

The size of the planet was estimated because it was too far away to accurately measure. Astronomers observed Pluto moving against background star, blocking the star’s light. Combining the distance and orbital speed with the amount of time the star was dim, they could estimate it’s width. As more stars passed nearer Pluto, estimates were downsized continually.

Moon In 1978, Pluto’s large, close orbiting moon Charon was discovered.

Other Planets? As seen by the Hubble space telescope. In 1801 the planet Ceres was discovered orbiting the Sun between Mars and Jupiter. In 1802 the planet Pallas was found in the same orbital zone. Ceres Pallas

Asteroids? or were they The discovery of Juno and Vesta soon followed. Could they all be planets? or were they Asteroids?

How many planets are there anyway?

Weird FactS: Pluto is about 70% rock and 30% ice. Pluto has less than 5% the mass of Mercury. Pluto has a tipped, oblong orbit around the Sun. Pluto and Charon has a double tidal lock, meaning they show only the same face to each other. Pluto shares its orbit with other small icy objects and debris. Weird FactS:

More… On Pluto you would weigh 10 pounds. The average high temperature is -365 degrees F. The New Horizons spacecraft, launched in 2006, will travel 53,000 mph through the solar system. It will test the atmosphere of Pluto and take pictures.

Hubble Space telescope Gave us high-resolution images of Pluto and led to the discovery of two new moons.

Pluto with its moons: Charon, Nix, and Hydra The Greek beast Hydra had nine heads. (Pluto is the 9th planet.) Nix is the Greek goddess of Darkness and night, and the mother of Charon, Pluto’s other moon.

Asteroid Ida If a space object has a moon, is it a planet? This asteroid was photographed by the Galileo space probe in 1994. It has a moon called Dactyl.

The Kuiper Asteroid Belt Slowly orbiting icy debris

A demotion ! In 2006, Pluto was declared by the International Astronomical Union to be a dwarf planet.

Like I’m supposed to care??