On March 13, 1781, German-born astronomer, William Herschel peered through his telescope at what he thought was a comet. After reporting his findings it was realized that what he had seen was not a comet at all, but a planet. The planet was Uranus and it was the first of the planets to be revealed by using modern technology, the telescope.
Uranus, is the seventh planet in distance from the Sun and one of the four Jovian planets, which also include Jupiter, Saturn, and Neptune. Orbiting the Sun at an average distance of 2.88 billion km, the planet takes 84.3 years to complete one full revolution around the Sun. Uranus has been visited by a spacecraft only once—by the U.S. Voyager 2 probe in 1986. Before then, astronomers had known little about the planet, since its distance from Earth makes the study of its visible surface difficult even with the most powerful telescopes available.
Most planets orbit the sun by rotating and creating days and nights as Earth does. Uranus does not, it’s poles are on its sides with an axial tilt of 90°. This is most likely due to Uranus being subject to an impact by a large object at some point in it’s history. The planet spins from north to south instead of west to east. Because it rotates on its side at any given time one pole is pointed towards the Sun. This results in one pole experiencing 42 Earth years of day followed by 42 years of night. When the North Pole is in the Sun, the South Pole is in darkness and vice-versa. The four seasons of Uranus each last 21 Earth-years.
Storms on Uranus have been photographed by the Hubble Telescope, and may be a recurrent feature of the changing seasons. Undetected before because previous seasonal changes could not be observed from Earth based instruments. The Northern Hemisphere of Uranus is just now coming out of the grip of its decades-long winter. As the sunlight reaches some latitudes, it warms the atmosphere causing storms.
Uranus has perhaps the most featureless exterior of all the known planets in the solar system. Uranus’ blue color is the result of absorption of red light by methane in the upper atmosphere. There may be colored bands like Jupiter’s but they are hidden from view by the overlaying methane layer. Molecular hydrogen and atomic helium are the two main constituents of the Uranian atmosphere.Uranus has no large spots like Jupiter’s long-lived Great Red Spot or the Great Dark Spot observed on Neptune.
Temperature and pressure increase as you travel inwards. A liquid or partially frozen mixture of water, methane, and rocky minerals may lie beneath the hydrogen and helium. Unlike the region where the oceans and air meet on Earth, though, there probably isn’t a sharp boundary between the layers of Uranus. The atmospheric pressure is so great that the liquid and gas merge in a slushy transition zone. This zone surrounds a dense, rocky core containing silicates and iron.
In 1977 astronomers discovered that narrow rings encircle Uranus. The rings are much thinner, darker and fainter and comprised of smaller material than the rings of
Saturn. Some of the particles are as large as SUVs, though. These large particles suggest that the rings formed fairly recently, when a small moon was pulverized by a collision with a comet or asteroid.
Uranus has 27 moons which are all named after characters from works by William Shakespeare or by Alexander Pope. Uranus’s five largest moons range from about 240 to 800 km in radius. All were discovered telescopically from Earth, and ten small inner moons were found by Voyager 2 in 1985–86. The largest moon, Titania, is an icy world covered in impact craters. Many of the moons are covered in rift valleys imply extension and fracturing of their surfaces.
|1. Cordelia2. Ophelia3. Bianca
|8. Rosalind9. Mab10. Belinda
|15. Francisco16. Ariel17. Umbriel
|22. Trinculo23. Sycorax24. Margaret
- There are several different pronunciations of Uranus the most common being “u-ra-nus” followed by “ur-unus”
- Uranus is the second least dense planet after Saturn
- Even though Neptune is further from the sun, Uranus is the coldest planet in the solar system
- The only spacecraft to visit Uranus is Voyager 2 which passed in 1986 passing at a distance of 81,500 km