The seventh planet from the sun is URANUS, which has six letters. It was discovered in 1781 by William Herschel and is the third largest planet in our solar system. It is composed mainly of hydrogen and helium and has a blue-green hue due to the presence of methane in its atmosphere. URANUS has 27 known moons and 13 rings. It takes 84 Earth years to orbit the sun and its axis is tilted at an angle of 98 degrees.