Pluto is a very tiny planet. Some suggest that it is not a planet, but an escaped moon. However, scientists could not obtain more details about it except for a few helter-skelter collections of facts. This is because Pluto is not only tiny, but it is too far away. It is estimated that the distance could be anything from 4730 to 7375 million km away from the sun. (3,674,488,000 miles).
The diameter of Pluto is 3,400 miles, i.e. 5440 km. It has a mass of about 1/20 as that of the earth, which is also five times bigger than Pluto.
It was Clyde William Tombaugh, an American astronomer, who discovered Pluto on Feb. 18, 1930 at Lowell Observatory, Flagstaff, Arizona, from the photograph taken, twice, hardly three weeks before it was recorded. Since it is very far from the sun, its period of one revolution is 248.54 years. And a day here is calculated to be about one week when compared with the earth’s. Similarly, a year on Pluto also varies to 2.5 centuries earth years!
Owing to its orbital eccentricity it could move very closer to the sun at times. However, Pluto remains the coldest planet, having the estimated temperature of – 360 degree C.
Pluto was discovered per chance because it has a sway over the orbits of the other two planets, Uranus and Neptune. It is made of rock which is enveloped by mostly ice and water, besides methane.
In 1978, another astronomer called, James Christy who scrutinized this planet observed a hump. On close examining of it, he found that it was a moon, which was later named as Charon. It orbits one another. Charon that is bigger three times than the moon of the earth remains stationary. Charon is half the size of the Pluto. An interesting factor about them is that, their togetherness reminds one like the dumbbells in a gymnasium!
It is so tiny and too far away that the pictures taken from the Hubble spacecraft showed it: almost the size of a cricket ball!