Description:

Lying deep in the void, Uranus is practically invisible to the naked eye. Even through the telescopes. It is difficult to study this planet in great detail. Only recently, the spacecraft Voyager 2 unveiled many of the secrets of Uranus. On January 24, 1986 at 1800 GMT, Voyager locked in on Uranus and was there for about 6 hours. Voyager has taught the scientists more about Uranus that they had learnt in the entire 205 years since its discovery by the then amateur astronomer Sir William Herschel in 1781.

Uranus is so far from the Sun - about 19 times than that of the distance between the Earth and the Sun, that from Uranus, the Sun appears as only a tiny disk of intense light. This massive planet with a diameter of 15800 km is like Jupiter or Saturn. At the center of the planet, we find a core of rock and ice, slightly larger than the Earth with a temperature of about 7000 degrees C. This is hotter than the surface of the Sun! The atmosphere of Uranus is made up of hydrogen, helium and a large amount of methane which gives it a bluish-green color. Uranus rotates on its own axis in about 17 hours 12 mins. Like Venus, the sense of rotation is retrograde. Uranus takes 84 years to complete one revolution around the Sun.

Image: Rotation of Uranus 
Credits: E.Karkoschka(University of Arizona and Planetary Lab) and NASA

The Rings of Uranus:

The rings of Uranus are made up of particles in two distinct size ranges. Many are between centimeters and meters across, but most are no more than few thousandths of a millimeter across. Uranus has a ring system, discovered in March 1977, even before the arrival of Voyager 2. The discovery of Uranus' ring was very interesting. In 1977, Uranus was to pass infront of a faint star.This phenomenon is known as an occultation. As the scientists aimed their telescopes to watch the occultation, the star seemed to flicker five times, there after, Uranus covered it when the star, reappeared, it again winked five times. Scientists concluded that this was due to new rings around this planet.Later researches found four more rings. Voyager 2, has discovered three more rings around the planet. All these rings are dark, thin and narrow. They are composed of lumps of rocks which lack an icy coating, making them appear dark and invisible.

Before the observations of Voyager, only five moons of the planet were known. They are Oberon, Umbriel, Titania, Ariel and Miranda. Voyager has discovered ten more moons of Uranus. The photographs of Titania and Oberon showed that the surface of both the moons were pocked. with meteoritic impacts which had pulverized the gray surface and exposed an underlying layer of ice. Both these moons are about 1500 km in diameter.
The recent discovery of the new rings and moons around planet Uranus have proved right an Indian astronomer Dr.J.J.Rawal, and Director, Nehru Planetarium, Mumbai. He had in has research papers in international journals specified in 1981, the locations of the satellites and rings in the region where they were spotted by Voyager 2.

Interesting Facts:

-The Sun is 363 times as bright from the Earth as from Uranus.
-Uranus is 14.5 times as massive as the Earth.
-If Uranus were hollow, it could contain 64 Earths.