Winter has arrived! Stay aware and be prepared for the season ahead. Uranus is the third "gas giant" planet of four in proximity to the Sun. Overall, Uranus is the seventh planet in our solar system, residing at an average distance of 1.
Its rotation is quick, at about 18 hours, enough to flatten the planet at its poles a characteristic of all gas giants. It takes 84 years for Uranus to revolve around the Sun and the aqua-colored planet has 27 known satellites. Six of these satellite discoveries have been since Atmosphere and Weather: For many years, it was generally understood that Uranus was a bland planet.
However, recent analysis from the Hubble Space Telescope shows Uranus to be a weather dynamic planet, characterized by huge storms some covering half or more the United States in size , banded cloud cover and the brightest cloud tops in the outer solar system.
In late , the Hubble telescope discovered a dark cloud on Uranus. This storm was two thirds the size of the United States. Clouds enshroud the planet with a latitudinal banding like Jupiter and Saturn, although much more faint. The average temperature of the clouds is degrees F and ammonia and methane ice crystals make up the cloud composition. It has been recently found that wind speeds on Uranus range from 90 to mph and the planet's average temperature is a frigid degrees F.
The coldest temperature found in Uranus' lower atmosphere so far is degrees F. Findings from Hubble reveal that clouds circle Uranus at over mph. Shown at right, this near infrared picture taken by the Hubble Telescope reveals the bright cloud tops on the left side of the disk.
Like the other gas giants, Uranus has an atmosphere composed of mostly hydrogen, followed by helium and a little methane. What is very interesting about Uranus is that the planet has an enormous 98 degree tilt on its axis. Basically, it is laying on its side with the poles receiving the direct sunlight. This makes for extreme seasons and when the Sun rises at one of the poles, that pole will receive direct sunlight for 42 years.
Therefore seasonal variations are immense, in that as the dark side of the planet comes out of its 40 plus year slumber, the frozen atmosphere heats up dramatically causing violent storms. Just above the "surface" of Uranus lies the troposphere, where the atmosphere is the densest. The temperature ranges from minus degrees Fahrenheit minus degrees Celsius to minus F minus C , with the upper regions being the coldest.
This makes the atmosphere of Uranus the coldest in the solar system. Within the troposphere are layers of clouds — water clouds at the lowest pressures, with ammonium hydrosulfide clouds above them. Ammonia and hydrogen sulfide clouds come next. Finally, thin methane clouds lay on the top. The troposphere extends 30 miles 50 kilometers from the surface of the planet. Radiation from the sun and from space heats the stratosphere of Uranus from minus F minus C to minus F minus C.
The stratosphere contains ethane smog, which may contribute to the planet's dull appearance. Acetylene and methane are also present. These hazes help warm the stratosphere. Hydrocarbons are less abundant in the atmosphere of Uranus than they are of other giant planets, however. The stratosphere reaches almost 2, miles km above Uranus. The thermosphere and corona of Uranus reach temperatures of 1, F C , although scientists are unsure as to the reason. Because the distance to Uranus from the sun is so great, the amount of heat coming from the star is insufficient to generate such high temperatures.
Extending twice as far from the center of the planet as its surface, the far-reaching outer layers are unique to Uranus. They create a drag on the ring particles that orbit the planet. Although the planet looks to be a solid shade of blue, it contains stripes like Jupiter and Saturn. But the bands are faint, and are only seen with enhanced images. As with other gas giants, the zones form as gases within the region warm and rise, while in the belts, the gases fall back to the planet as they cool.
In the belts, the winds blow east, while they travel west within the zones. Watch it now, Wondrium. As one descends through the atmosphere of Uranus, the fraction of icy compounds begins increasing as the fraction of hydrogen and helium decreases. Here, the water, ammonia, and methane experience pressures around , bars and temperatures around Kelvin.
These conditions cause these materials to change into new phases and even break up and form new materials. On Earth, shiny gems are formed at high pressure. Deep into Uranus, diamond rain might form. Diamonds, for example, are a high-pressure phase of pure carbon.
They could form if the methane molecules, which also contain carbon, are broken up. The carbon atoms could condense into crystals of diamonds that would rain through the icy layer. At the very bottom of the icy layer, Uranus may even have an ocean of carbon under high pressure—which is basically liquid diamond—with floating chunks of solid diamond-bergs.
Uranus is also a place where a lot of water is at high pressure and temperature. In the atmosphere, Uranus has water in its usual molecular form, with two hydrogens bonded to an oxygen. But as the pressure and temperature increase with depth, water would break up into ions, like OH and H, which themselves would have positive and negative ionic charges.
After going deeper, at about 1. In superionic water, the oxygen ions from water bond together making a crystal lattice. The hydrogen ions then move freely through the oxygen lattice. Fluid motions in the ionic ice layer can generate the currents that create a dynamo in the planet. Voyager 2 discovered that the magnetic field produced from this dynamo is unusual. Before Voyager 2 measured the Uranian magnetic field, all observed planetary magnetic fields had looked like simple dipoles, with a north pole and south pole.
That means, there were many locations where the magnetic field lines were plunging directly into, or directly out of, the planet. This is called a multipolar magnetic field. Why would Uranus have such a multipolar field?
0コメント