The Solar System: Difference between revisions

* [[Useful Notes/Mercury|Mercury]]: smallest of the planets, closest to the Sun. It is small and very hot (apart from some permanently shadowed craters at the poles which ''may'' contain ice), with <s>no</s> the merest whisper of an atmosphere. Early scientists believed it to be tide-locked (one side permanently faces the sun), but it turns out it rotates 3 times for every 2 times it circles the sun (which, when combined with an elliptical orbit causes weird effects like "hot" and "cold" poles on the equator, and [[Alien Sky|the Sun doing a slow loop-the-loop in the sky once each 88-day Mercurian year]]). When ''Mariner 10'' flew by in 1974, it found the planet to be unexpectedly dense; scientists now believe it was originally similar in size and composition to Venus and Earth, but [[Earthshattering Kaboom|a massive impact with a leftover planetesimal]] tore away the atmosphere and most of the relatively light mantle, leaving the metal-heavy core behind.

* [[Venus]]: sometimes referred to as Earth's sister planet due to their similar sizes. It has an extremely dense atmosphere (surface presure is 90 times that of Earth) and can reach a surface temperature of 470 °C/870 °F (although the top of Maxwell Montes, almost 7 miles above the average surface level, it's a chilly 380 °C/716 °F and a...less squishy 60 bars of pressure). The culprit for all this? The greenhouse effect - most of that atmosphere is carbon dioxide. Earth started with the same amount, [[Sealed Evil in a Can|but it ended up trapped in carbonate rock]]. Venus also started with the same amount of water as the earth had, but it remained in vapor form (300 atmospheres worth) and created a [[Up to Eleven|super greenhouse effect]] with temperatures in the ''thousands'' of degrees<ref>This plus the slow rotation probably wrecked any chance at plate tectonics; instead of plates constantly sliding against each other, [[Lethal Lava Land|there seems to be intermittent vulcanism puncutated by the entire surface melting every 500 million years or so]]</ref>. Eventually the water molecules dissociated into hydrogen and oxygen and escaped into space, leaving Venus high and dry. Interestingly, the zone between 50 and 65 kilometers above the surface has pressures and temperatures right around Earth normal. Add to that the fact that an 80/20 nitrogen/oxygen mix would act like a lifting gas and [[The Empire Strikes Back|Cloud City]] would be right at home. Due to Venus being mythologically associated with femininity, by convention all geographic features there are named after women or female entities, except for Maxwell Montes and Alpha and Beta Regio.<ref>These features were first detected by ground-based radar in the mid-1960's; Alpha and Beta Regio were the first two terrain features to be isolated, and Maxwell Montes was named after James Clerk Maxwell, the formulator of the theory and equations of electromagnetism that ultimately led to the invention of radar</ref> There is some argument over whether the proper adjective is 'Venusian', 'Venerean', or 'Cytherean'.

** [[The Moon]]

* [[Mars (useful notes)|Mars]]

=== Gas giants ===

* [[Jupiter]]

* [[Saturn]]: Well known for its spectacular ring system. It's average density is less than that of water<ref>so if you were to put it in a tub of water, it would float -- but it would [[A Worldwide Punomenon|leave a ring around it]]</ref>, and despite its bland butterscotch appearance it has storms that rival any found on Jupiter. Plus it has [[wikipedia:Hexagon on saturn#North pole hexagon cloud pattern|a polar hexagon]]. How cool is that?

** [[wikipedia:Rings of Saturn|The Rings Of Saturn]]

* [[Useful Notes/Uranus|Uranus]]: It had been detected by astronomers as early as 1690<ref>John Flamsteed thought it was a star and named it "34 Tauri"; that designation was therefore available for [[Joss Whedon|a certain talespinner]] to apply to [[Firefly|the star system at the heart of his 'Verse]]</ref>, but Sir William Herschell actually identified it as a planet in 1789. It's 4 times the diameter of the Earth, which is still less than half the diameter of Jupiter. Minty green in color; it's denser than Jupiter and Saturn with a higher proportion of methane, ammonia and water. Voyager 2 passed by it in 1986 and observed few distinct clouds, [[Science Marches On|but later observations from Earth have revealed more]]. It has a set of coal-black rings (discovered in 1977) and is tilted 98 degrees on its axis - each pole spends 42 years in light and 42 in darkness. Also known for being the planet which the [[Star Trek|Enterprise]], like [[A Worldwide Punomenon|toilet paper]], [[Uranus Is Showing|circles while wiping out Klingons]].

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[[Category:The Solar System]]