Generalities: it is essentially a gaseous planet. It has clearly  smaller dimensions in comparison to Jupiter and Saturn. Its atmospheric composition shows, besides hydrogen and helium, a great fraction of other mixtures, mainly water, methane and ammonia. Just because of its composition the atmosphere on Uranus appears of light blue color. Even the quantity of heavier elements seems superior in comparison to Jupiter and Saturn and this enables its density to be higher. The main characteristic of Uranus is its great orbital inclination, which enables this planet to “roll” around itself along its orbit, by rotating arounds itself. Considering the duration of its year, the same parts turn to the Sun or they remain in the shade for very long times. Nevertheless the temperature of Uranus is rather levelled. An  interesting fact is the presence of a system of rings that, because of their smallness, are discovered only by  Voyager probes.

Observation: Uranus appears as a  star next to the limits of visibility in the terrestrial sky. Its magnitude is  about 5.7. Even if it is theoretically visible with a  naked eye under very clear and dark skies, it was discovered only in the modern epoch, in 1781 by the famous astronomer Herschel.
In reality its observation without any tools is extremely difficult, since it requires its exact location among the several starlets of similar brightness, besides the perfect conditions of the sky. Having a very slow motion among the stars, it practically goes to opposition every 12 months, being observable for long periods.

Satellites: the satellites of Uranus are numerous, but  almost all of them have very small dimensions and were discovered by  Voyager probes. Only four satellites overcome  1,000 Km of diameter (Ariel, Umbriel, Titania, Oberon). These last ones are observable from the Earth through half-professional telescopes.
 
 

- Visibility of planets during this month

- Mutual position of Earth and external planets

Go back to Home Page