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  It shall be moon, or star, or what I listJul 05, 2013 11:47 PM PDT | url | discuss | + share
 
Added 1 new A* page:Well since I lay off the caffeine three days ago I think the pages have been a little less jittery looking. : )
 
Say, if you have somehow managed to miss all my plugging of it so far, I am auctioning off a big new ink piece on eBay--the biggest ink thing I've ever done, in fact! Here it is in miniature:
 
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Let's see...sorting through my huge news item backlog, weeding out things I don't understand anymore, we come to...Miranda! I think I was trying to find an example of an astronomical body of a certain size, back when I was coming up with the planetoid Selenis and the Major landed on in the previous episode (trying to figure surface gravity and how big it would have to be for someone to be able to walk semi-normally, how far up they could be when they jumped, etc), and I came across the name "Miranda," which was supposedly a moon. That can't be a moon, I thought, it isn't named after a Roman god or what have you! Is it?
 
Well, as it turns out, Miranda is a moon--of Uranus!
 
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image by NASA (source)
 
Miranda is an icy little thing about 470 km across. Its surface, as you can see above in that composite of photos taken by Voyager 2 as it passed by in 1986--the only source of our close-up views of Miranda so far--is a crazy patchwork of smooth and scarred areas. There are two leading theories for how this occurred: Miranda may have had a complicated past with other moons of Uranus, and the gravity of these and Uranus itself could have served as tidal forces that pulled the watery moon into a bulged shape, causing friction and interior heating, leading to volcanism and big moon quakes and so on; the other theory goes that something pretty big smacked into Miranda at some point in the past.
 
That may not be too far out when you consider that we now know of twenty seven moons orbiting Uranus! Miranda is the smallest and innermost of the five "major" moons; inside Miranda's orbit are many smaller moons, as well as numerous dust rings that may have resulted from collisions--the inner area is complicated and apparently unstable; Wikipedia says, of some of the inner moons, "Desdemona may collide with either Cressida or Juliet within the next 100 million years."
 
Here's a diagram showing the relative sizes and positions of six of the moons--from left to right we have Puck, one of the larger of the inner moons, then the five major moons: Miranda, Ariel, Umbriel, Titania and Oberon; Titania, the largest, and the eighth-largest moon in our solar system, is still "about 20 times less massive than Earth's Moon":
 
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image by Vzb83 (source)
 
Have you noticed a pattern in the names of these moons yet? They're characters from Shakespeare! John Herschel, son of William Herschel, discoverer of Uranus, started naming them that way (and a few after characters from a poem by Alexander Pope) in 1852, a few years after the first of the moons were discovered, and I say, good on him! Those are some good moon names. Miranda is one of nine from the most used play, Shakespeare's Tempest.
 
Here's a diagram showing just how busy Uranus' inner moon area is--and this is only the stuff we know of so far:
 
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image by NASA (source)
 
Most of the known inner moons were discovered by the Voyager 2 fly-by, showing up in photos like this:
 
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image by NASA (source)
 
Some of the inner moons, and most of the small outer moons, have been discovered more recently as tiny little blobs seen through powerful telescopes, like Mab, the outermost inner moon, spotted here by Hubble in 2003:
 
Image
image by NASA (source)
 
So anyhow the lesson is that if you ever run across a moon with a Shakespearean name, it's probably from Uranus. Fact.
 
 
 
 
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