24 October: Umbriel

On this date in 1851 Uranus' moon Umbriel was discovered by William Lassell. 10 things you might not know about it:

1. When William Herschel discovered Uranus’ moons of Titania and Oberon at the end of the 18th century, he speculated that there were four more moons. Roughly half a century later, William Lassell found two of them, Ariel and Umbriel.
2. Umbriel is Uranus’ third largest moon in terms of size and the fourth largest in terms of mass.
3. It is also the darkest, a fact which contributed to the selection of its name. Like other of Uranus’ moons it is named after a character in Alexander Pope's poem The Rape of the Lock. Umbriel is the "dusky melancholy sprite", which also suggests the Latin word umbra, meaning shadow.
4. Why is it dark? Scientists believe that energetic particles from Uranus’ magnetosphere react with methane deposits on the moon’s surface and cause them to darken. Not only that, but it is less reflective of light.
5. Based on spectrograph analyses, astronomers believe Umbriel is made up of water ice, with 40% of its mass made up of something yet to be identified. Most likely this means it has a rocky core and a mantle of ice.
6. It takes just over 4.1 Earth days to orbit Uranus and the same amount of time to rotate, which means that like our own Moon, it is tidally locked with Uranus with the same side of it always facing the planet.
7. Umbriel is about 266,000 km (165,000 mi) from Uranus. It is the third farthest from the planet among its five major moons.
8. Because Uranus orbits the Sun almost on its side, and Umbriel orbits in the planet's equatorial plane, it has some extreme seasons. Both northern and southern poles spend 42 years in complete darkness, and another 42 years in continuous sunlight.
9. The only images we have of Umbriel come from the Voyager 2 probe. When the probe passed by the northern hemisphere of Umbriel was in darkness so only the southern hemisphere was photographed. There are currently no plans to send any more probes back to photograph the rest.
10. The craters on Umbriel are named after dark sprites from different cultures’ mythology. The largest is Wokolo with a diameter of 210 kilometers. The most prominent is Wunda, which although it is smaller with a diameter of about 131 kilometers, is the most noticeable because it has a ring of bright material on its floor (probably from the impact). Other craters include Vuver, Skynd, Fin, Peri, and Zlyden.

Killing Me Softly

Sebastian Garrett is an assassin. It wasn’t his first choice of vocation, but nonetheless, he’s good at it, and can be relied upon to get the job done. He’s on top of his game.

Until he is contracted to kill Princess Helena of Galorvia. She is not just any princess. Sebastian doesn’t bargain on his intended victim being a super-heroine who gives as good as she gets. Only his own genetic variant power saves him from becoming the victim, instead of Helena. 

Fate has another surprise in store. Sebastian was not expecting to fall in love with her.

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