ASTR Exam 2 Cheat Sheet.docx - Solar System has 1 star 8 planets 5 dwarf planets 139 moons countless small solar system bodies 1-10 billion scale Sun is

ASTR Exam 2 Cheat Sheet.docx - Solar System has 1 star 8...

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Solar System has 1 star, 8 planets, 5 dwarf planets, 139+ moons, countless small solar system bodies. 1-10 billion scale: Sun is a large cantaloupe, Earth is ball point, Jupiter is fingertip, Pluto is dust speck. Voyage Exhibition is name of model solar system using 1-10bil scale on National Mall in D.C. (shows a straight line instead of the orbits Solar system is mostly empty space. Planets/moons orbit the Sun all in the same direction, counterclockwise from Earth’s N-Pole. Most planets rotate counterclockwise too, except Venus rotates backwards and Uranus rotates with equator perpendicular to its orbit. Solar System is basically “flat” and disk shaped. Mercury orbit: tipped 7° to Earth’s orbit Other planets are inclined no more than 3.4° Orbits of dwarf planets (Pluto) can be very inclined. Terrestrial (Earth Like) Planets: closer to sun, closer together, smaller size/mass, higher density, comp: mostly rock and metal, solid surfaces, warmer surfaces, few moons, no rings (Mercury, Venus, Earth, Mars) Mercury is barren airless world, heavily cratered Venus “Earth’s evil twin”, surface perpetually shrouded by thick sulfuric acid clouds, Hot atmosphere, volcanoes, few impact craters Earth is only terrestrial planet with a large moon. Moon heavily cratered surface with large dark plains, mare , that have few craters Mars Water ice clouds, polar ice, and volcanoes on Mars, Earth like surface, Cold, Phobos and Deimos Jovian (Jupiter Like) Planets: Father from sun, farther apart, larger size/mass, lower density, comp: hydrogen, helium, “ices”, no solid surfaces, colder temp at cloud tops, many moons, all have ring systems (Jupiter, Saturn, Uranus, Neptune) Jupiter king of planets, Most massive, swirling cloud stripes punctuated by massive storms (Great Red Spot) Saturn lord of rings, mostly hydrogen and helium Uranus equator at nearly 90° to orbit, more methane = blue tint Neptune Dark, cold and whipped by supersonic winds, methane in atmosphere Dwarf Planets Eris, Pluto, Makemake, Haumea (comp: mostly ices) Ceres (comp: mostly rock) Asteroids rocky, airless worlds that orbit sun, too small to be called planets, irregular in shape, battered by impact cratering, formed inside frost line Rubble Pile Asteroids form when asteroid is smashed to pieces by impact and then fall back together Most asteroids orbit in belt between Mars & Jupiter and in a thick disk, if NASA were to go through belt wouldn’t have to worry about hitting any bc so sparse. Comets dirty snowballs of ices, rock, and dust, mostly orbit beyond Neptune, close to sun then has long tail, formed outside the frost line Meteroids catch all for small debris, comp is whatever, size is what matters, interplanetary debris that falls through Earth’s atmosphere Meteors streak of light caused by meteoroid when it enters Earth’s atmosphere (shooting star) Meteorite space rock on the ground Types of meteorites: Stonys 94% of meteorite falls, Rocky comp, Irons 5%, Iron-nickel alloy, Stony-irons 1%, mixture of the two and if Earth passes through the orbit we see showers Kuiper Belt
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