Uranus is planet very much like Jupiter and Saturn, a big mass of gas without a firm surface. But it is much smaller than either of them and much further from the sun. As it receives much less heat from the sun, the temperature on its surface is lower. It has a very tick cloud of methane which is just not possible on Saturn or Jupiter.
It is this presence of methane on the planet which gives it its characteristic blue color. It was only in March 1977 did the astronomers notice that there were rings around the planet, just like those around Saturn but much thinner. The circles like Jupiter are very dark, but are composed of large particles and fine dust as that of Saturn.
Up till now 11 rings have been seen but they all are very dull. This discovery of rings around Uranus is of substantial significance as this shows that rings around planets are a common feature and not some specialty of Saturn only.
Uranus was discovered by a British Astronomer William Herschel while methodically searching the sky with his 160 mm telescope in March 1781. Initially he thought it was a comet. The planet has been sighted many times before but was dismissed as just another star. The first time it is recorded as being seen by John Flamsteed in 1690.
It was named Uranus in consistency with the other planet names taken from the classical mythology. Its vast distance from the sun makes it very difficult to observe. In 1787 Herschel discovered 2 satellites and they were named Titania and Oberon. Later more satellites were discovered by other astronomers.
Although the planet was shaped at around the same time and the same manner as Saturn, its axis of rotation is very different. Instead of being perpendicular, it is parallel to the plane of its orbit. Its extraordinary position can be a consequence of some collision with another planet maybe the size of Earth.
Its satellites also must have tilted with it as they revolve around Uranus in equatorial orbit. There can be another explanation for this. It is very possible that it's sideway movement through our solar system is because of gravitational disturbances from other planets.
Voyager 2 is the only spacecraft which has visited this planet on Jan 24 1986.When Voyager 2's passed Uranus, its south pole was pointing more or less directly at the Sun. As a result Uranus' polar section gets more energy from the Sun compared to its equatorial regions. But still Uranus hotter on its equator than it is at its poles. The reason for this is still not clear. Voyager 2 took the first and up till date the only clear picture of the planet in January 1986.
On a clear night; it is only sometimes and that to a very faint Uranus planet can be seen by naked eyes. But if you know where to look in the sky it is easy to spot Uranus with a pair of binoculars. If a small astronomical telescope is used to see the planet as a small disk. |
