irregular moons

(A table of contents is available. This series will remain open for additional posts and the table of contents up-to-date as new posts are added.)

Part Nine: Moons, Moons, and More Moons

Just like how planets orbit a star and the stars orbit the center of a galaxy, and two stars might orbit each other, and two pairs of stars might orbit each other, and asteroids sometimes orbit each other, so too do planets get their own tag-alongs orbiting them. These celestial bodies–natural ones, mind, not constructed ones–are called moons or satellites.

Moons are defined by both size and composition. Major moons have enough mass that they retain a mostly spherical shape while minor moons are smaller, with less mass, and therefore are frequently oddly shaped. The key to size and shape is 200-300km in size, with minor moons being less than that size and major moons being larger. Moons tend to be comprised of either rock or ice, depending on where in the system it’s located. Obviously, like the formation of icy planets, icy moons must form outside the frost line.

Gas Giants:

Moons collect around gas giants in kind of three groups:

  • Small, irregular rocky minor moons gathered in an orbit on the outer edge of where the planet could potentially have rings. They are generally only 10-100km in size and make sure to leave 0.25-1.5 Earth-radii of space between each other.
  • A handful of large major moons gathered in orbit outside where the planet’s rings are. They leave more than half the planet’s size between each other. They may even have minor moons of their own.
  • Tiny, irregular minor moons–often captured asteroids–orbiting distantly, at the very edge of where they’re able to orbit. Generally in the 10s of kilometers in size, these minor moons orbit on very eccentric and inclined paths, and sometimes even backwards (retrograde).

Don’t forget! Moons clear out the debris from their orbits paths! So if you position a moon in the midst of a gas giant’s rings, they’ll create a gap in the rings where they orbit. Some major moons of gas giants cause major gaps in the rings, even though they’re not actively orbiting in the rings to clear it out. The reasons for this are a bit complex, but if you wanted to build a ringed gas giant with a major moon close-ish to the planet and a major gap in its rings, you totally could!

Terrestrial Planets:

Terrestrial planets don’t tend to accumulate many moons. They may have enough gravity to pull in some asteroids to become moons, like Mars’ two moons. (Remember that asteroids are mostly chunks of rock that are small enough that they would be considered minor moons.) To go along with this, distant planets are likely to have more moons, and close-in planets will have less.

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I… wrote Game of Thrones fanfic? Which is weird because I’ve only watched like two episodes of the show and read like none of the books. But I know a lot about it anyway and I couldn’t stop thinking about Elia, especially with all the awesome Rhaenys stuff that Cinn has been doing. Sooooo… yeah. This is my take on one of the most tragic characters in the series. Please excuse any continuity errors in light of the fact that I have no clue what I’m doing.



Elia Martell knew that having children might kill her.

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New video on the Hubble Sequence! Had a lot of fun making this one, enjoy!

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The First Irregular Moon Discovered on this Day!

On September 19, 1848, astronomers William Cranch Bond, George Phillips Bond and William Lassell discovered the first non-sperical, irregular moon orbiting the planet Saturn, which they named Hyperion (Ὑπερίων) after the Greek god/titan who was the brother of Cronus (the Greek equivalent of Saturn). Looking like a giant potato in the sky, Hyperion is the second largest non-sperical satellite discovered, measuring 360.2×266×205.4 km. Lassell and Bond both observed Hyperion independently of each other only days apart, and only a year after William Herschel had published Results of Astronomical Observations made at the Cape of Good Hope in which he suggested the name scheme for the first seven moons of Saturn, and which Lassell and Bond used when they proposed Hyperion.

Images of Hyperion courtesy NASA/Cassini

Tumblr Clan and Nation Leaders

United sanctuary:
Nation leader - lightseeker-yuki
Royal Paladin - lightseeker-yuki
Oracle Think Tank -
Shadow paladin - colorfulnitemare
Gold paladin - divergent-vanguard
Genesis - tsukuyomi-chan
Angel feather - version109

Dragon Empire:
Nation leader - dragonicvanguard
Kagero - dragonicvanguard
Narukami - narukamitoshiki
Tachikaze - chaos-axel
Murakumo - stealthrogue
Nubatama - my-name-is-superkip

Dark Zone:
Nation leader - 
Dark Irregulars - 
Pale Moon -  zheawesomecat
Spike brothers - blackthornsbramble
Gear Chronicle - enaki

Magallanica:
Nation Leader -  hayaakira
Aqua force - hayaakira
Granblue - captainnightstorm-vgrp
Bermuda triangle - codearkada

Zoo:
Nation Leader - 
Neo Nectar - yuaikai
Great Nature - colorfulnitemare if he loses for shadow paladin
Megacolony - turtlecannons

Star Gate:
Nation Leader - cardfighterculture
Link Joker - animeisparadoxical 
Nove grappler - katsuragikamui or zerogman
Dimension Police - cardfighterculture

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New video on Irregular Galaxies! Enjoy!