ISALC: Earth Science, Level 200

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Pluto by Artem Lebedev

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There are nine planets in our Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and last is Pluto. I decided to write about Pluto because it is the smallest and slowest planet in our Solar System. It is smaller than a lot of the other planets' moons, except Earth's moon. Also Pluto is the farthest planet from the sun, but not always. Part of Pluto's orbit goes inside Neptune's orbit and it passes closer to the sun than Neptune does. (Marshall & Allen Rosskof, Earth Science, page 86). That is why our spacecraft has not visited it yet. We have just pictures of its surface.

Clyde Tombaugh who is the one of the most famous astronomers in the world discovered Pluto in 1930. Astronomers began to look for this planet because after they discovered Neptune, they noticed that something was changing the orbits of Uranus and Neptune. Mr. Tombaugh spent a long time to take pictures of the area of the sky where the unknown planet should be. Finally, he found it and named it Pluto.

Here are some interesting facts about Pluto. Pluto is the Roman god of darkness and the underworld. This planet got this name as the result of a suggestion of a young British girl.

This is the symbol of the planet Pluto, which is the combined letters "P" & "L", either for Percival Lowell (American astronomer who founded the Lowell Observatory in Arizona in 1894) or for Pluto.

Pluto is far away from the sun; this distance is 3.5 billion (3,500,000,000) miles. When Pluto gets closest to the Sun it is 2.7 billion (2,700,000,000) miles away and we still can't see it. To see Pluto you should use a special telescope and know the directions where it is, which is very difficult. Even if you find the planet it will be nothing more than stars' light.

Also Pluto has just one moon which is called Charon. It is half the size of Pluto. Some astronomers think that Pluto and its moon Charon is a double planet, and others don't. Charon orbits about 19.640 km from Pluto on average. Pluto's moon is in a synchronous orbit around it. And one revolution takes the same time for them.

Pluto is the only planet in our Solar System that we haven't explored with a spacecraft. All what we know that Pluto is the dark and frozen planet. "The current studies tell us that Pluto is made up of a mixture of rocks and several kinds of 'ices'. Scientists believe that most of the ices that make up Pluto are frozen methane and ammonia". (http://www.dustbunny.com/afk/planets/pluto/pluto.htm).

The average temperature of Pluto is 393 degrees below zero. The surface of Pluto is very cold and dark because Pluto can't get light and heat from the sun. Also scientists, who have observed Pluto, know that it has very thin atmosphere. Its atmosphere is too thin to have any kind of life on it.

There are many differences between Earth and Pluto. First Pluto has about 1/500th of the mass of the Earth. There is a big difference between their sizes; Pluto's diameter is about 1/5 the diameter of the Earth, which is 18% (Earth-12.756 km, Pluto-2.300 km). Pluto is 39 times farther from the sun than the Earth. Also a year on Pluto lasts 248 Earth years. Finally, Earth has life on it and Pluto doesn't.

I would like to visit this planet and be the first who has made prints on it. Nevertheless, I know that it is very dangerous and impossible. So I think that thinking about visiting Pluto can be just a dream.