Lyceum B - Astronomy - Week 30 - Uranus

Jun 2, 2022
3 min read

Uranus is the seventh planet from the Sun. It is the third gas giant.

Because it is so far away from the Earth, without a telescope you can not always detect it and when you can detect it, it is barely visible. When you look at Uranus through a telescope it has a green color.

Uranus was discovered in 1781 by amateur astronomer, William Herschel. But its distance has prohibited us from gathering a lot of data on Uranus until Voyager 2 mission in 1986.

William Herschel (1738-1822) - was a German-British professional musician and composer. But his hobby was astronomy. And while working in England in 1781, he saw this greenish blob through his homemade telescope, which turned out to be Uranus. King George III created a special post for Hershel as a result where Hershel devoted the rest of his life to astronomy.

Uranus is made up almost entirely of water, it has no solid surface, just a few clouds above and is extremely cold.

Uranus has 10 narrow, dark rings (so dark they can not be seen from Earth) and 15+ moons. Uranus is tilted on its axis to such a point (at angle of nearly 98° to the vertical) that one end faces the Sun and the other end faced deep space on its side. This makes the rings of Uranus look almost vertical and it has an unusual effect on its seasons. Each pole spends 42 years in darkness and 42 years in sunlight.

From Universe today. com:

The rings of Uranus were first discovered in 1977 by astronomers James Elliot, Edward Dunham, and Douglas Mink. When he first discovered Uranus 200 years before, William Herschel reported seeing rings around Uranus, but his telescope probably wasn't powerful enough to reveal them. Additional rings were discovered in 1986 when NASA's Voyager 2 spacecraft made its flyby, and then two more outer rings were turned up by the Hubble Space Telescope in 2003-2005.

The rings of Uranus are dark and opaque, with a very low albedo. Astronomers believe they are made of water ice mixed with organic molecules. Unlike Saturn's rings, the rings of Uranus are very narrow; just a few kilometers wide.

Uranus' rings consist of 3 major groups. There are the narrow main rings, the dusty rings, and the newly discovered outer ring system.

Astronomers think that the rings of Uranus are being shepherded by small moons in the ring system. Without these shepherd moons, the rings of Uranus would spread out radically and dissipate into space. It's also believed that there's some process that's replenishing the ice particles in the rings; perhaps collisions between ice particles in the rings; perhaps collisions between icy objects in the rings.

One of the small moons of Uranus, Miranda, is a puzzle. Its surface shows arrow shapes and oval patterns like racetracks. It has a towering cliff that is higher than Mount Everest (if it was on Earth, it would reach up to the orbit of the space shuttle).

Miranda - nasa.gov

http://solarsystem.nasa.gov/moons/uranus-moons/miranda/in-depth/

Like Frankenstein's monster, Miranda looks like it was pieced together from parts that didn't quite merge properly. At about 500 km in diameter, its only one-seventh as large as Earth's moon, a size that seems unlikely to support much tectonic activity.

Yet Miranda sports one of the strangest and. most varied landscapes among extraterrestrial bodies, including three large features known as "coronae," which are unique among known objects in our solar system. They are lightly cratered collections of ridges and valleys, separated from the more heavily cratered (and presumably older) terrain by sharp boundaries like mismatched patches on a moth-eaten coat. Miranda's giant fault canyons are as much as 12 times as deep as the Grand Canyon. Due to Miranda's low gravity and large cliffs, a rock dropped at the edge of the highest cliff would take a full 10 minutes to reach the foot of the cliff.

Scientists disagree about what processes are responsible for Miranda's features. One possibility is that the moon may have been smashed apart in some colossal collision and the pieces then haphazardly reassembled. Another, perhaps more likely, scenario is that the coronae are sites of rocky or metallic meteorite strikes which partially melted the icy subsurface and resulted in episodic periods of slushy water rising to Miranda's surface and refreezing.