Paragraph on “Pluto-The dwarf planet” complete paragraph for Class 9, Class 10, Class 11 and Class 12

Pluto-The dwarf planet

Till around 1929 the outermost planet known to man was Neptune. In 1915 the American astronomer, Percival Lowell discovered that the movement of Uranus and Neptune was affected by something which existed beyond Neptune. This opinion led to the search for a new planet and it was in February 1930 that an astronomer named Tombaugh discovered Pluto the ninth planet. Pluto has a diameter of about 2445 kilometres which is about one fifth of the Earth’s and it takes 6 days and 9 hours to complete one rotation around its axis. 4497 million km away from the sun and travelling at an average speed of 4.6 kilometres per second it takes about 248 earth years to complete one revolution around the Sun. It is the coldest planet in the solar system and has a temperature of —24° C and has only one moon which is approximately half its size. Pluto is so far away that from its surface the Sun is visible only as a star.