Uranus (planet)
Uranus is the seventh planet from the Sun in our solar system. It is a gas giant (also known as a Jovian planet, after the planet Jupiter).
Uranus is so far away from the sun that it takes 84 years on Earth to complete one orbit. In other words, a year on Uranus is equal to 84 years on Earth.[1]
Uranus was discovered using a telescope by astronomer William Herschel in 1781.[1]
Parameters for classification as a planet
Uranus is classified as a planet by the International Astronomical Union for meeting the following criteria:[2]
- Orbits the sun;
- Has mass sufficient for its gravity to form a nearly round shape;
- Has mass sufficient for gravity to clear a path in its orbit.
Physical characteristics
Uranus's distance from the sun is about nineteen and a half times that of earth [3], has a volume 63.1 times the volume of the Earth [4] a diameter of 1.60592 x 105 km and with a mass fourteen times that of Earth (14 Earth masses or 8.6849 X 1025 kg), is the lightest of the outer planets. It has a smaller surface gravity, about 86% of Earth's.[5][1]
It has a much colder core than the other gas giants and radiates very little heat into space.[6][1]
Uranus has no solid surface. Eighty percent or more of Uranus is an extended liquid core of icy materials composed of water, ammonia and methane and higher density materials beneath.[1]
The atmosphere is composed of mainly of hydrogen and helium and has a temperature of about -216 °C.[7] Its atmosphere has small amounts of methane, water and ammonia. Uranus gets its blue-green colour from a combination of light absorbed by the methane layer and light reflected by clouds beneath the methane. The sunlight passes through the methane, is then reflected by the clouds back through the methane layer where the red light portion of the spectrum is absorbed leaving only the blue-green spectrum to pass through, making the atmosphere appear blue-green.[1]
Rotational characteristics
Uniquely among the planets, it orbits the Sun on its side with the poles pointing in the axial plane almost directly at the sun in the orbital plane; its axial tilt is over ninety degrees to the ecliptic.
Seasons
Uranus has a nearly circular orbit with the result that it is at almost the same distance from the sun throughout the year. Since the axis of Uranus is tilted by 82°, Uranus has 20-year-long seasons and it is always cold. For almost one-quarter of the Uranian year (about 84 Earth years), the Sun shines directly over each pole, leaving the other half of the planet in the dark causing a long winter. While its polar orientation switches back and forth as it orbits the sun, as the Sunlight reaches some latitudes for the first time in years, it warms the atmosphere and triggers gigantic springtime storms over areas nearly the size of North America with temperatures of 300° below zero. [8][9]
Natural satellites
Uranus has twenty-seven satellites, named after characters from Shakespeare or Pope, the largest being Titania, Oberon, Umbriel, Ariel and Miranda. Unlike some moons of the other giant planets and Earth's, none of them are larger than the dwarf planets Eris and Pluto.
- Cordelia
- Ophelia
- Bianca
- Cressida
- Desdemona
- Juliet
- Portia
- Rosalind
- Mab
- Belinda
- Perdita
- Puck
- Cupid
- Miranda
- Francisco
- Ariel
- Umbriel
- Titania
- Oberon
- Caliban
- Stephano
- Trinculo
- Sycorax
- Margaret
- Prospero
- Setebos
- Ferdinand
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Solar System Exploration: Uranus NASA
- ↑ Honey, I Shrunk the Solar System NASA. “The International Astronomical Union has decided that, to be called a planet, an object must have three traits. It must orbit the sun, be massive enough that its own gravity pulls it into a nearly round shape, and be dominant enough to clear away objects in its neighborhood.”
- ↑ 19.6 AU or 2,870,972,200 km
- ↑ of 6.833 X 1013 km3
- ↑ 8.43 m/s2 or 27.7 ft/s2. By comparison, an object of 100 pounds on Earth will weigh 86 on Uranus. Kilograms is in fact a measure of mass, not weight. 100 Kilgrams on Earth is still 100 kilograms on Uranus. The metric measure for weight is newtons (N). 100 kilograms on Earth where gravity is just a little less than 10 m2 weighs approximately 1000 N. The same mass on Uranus would be 860 N.
- ↑ Hawksett, David; Longstaff, Alan; Cooper, Keith; Clark, Stuart (2005). 10 Mysteries of the Solar System. Astronomy Now. Retrieved on 2006-01-16.
- ↑ -357 °F; 57 K
- ↑ The effect of rotation National Maritime Museum
- ↑ Seasons on Planets in the Solar system [1]