The Solar System 6/23

Transcription

1 6/23 The Solar System I. Earth A. Earth is the prototype terrestrial planet 1. Only planet in the solar system (we know of so far) with life 2. Temperature 290 K B. Physical Characteristics 1. Mass: kg 2. Radius: 6400 km 3. Atmosphere: 80% N 2, 20% O 2, traces of other gases 4. Distance from Sun: 1 AU = 150,000,000 km 5. Rotation period: 1 day = 24 hr 6. Revolution period: 1 year = days 7. Presence of life C. Satellite 1. Moon 2. Distance from Earth: 380,000 km 3. Mass: kg 4. Radius: 1750 km 5. Sidereal period: days (= rotation period) 6. Synodic period: days 1. Solid inner core iron. 2. Liquid outer core iron source of Earth s magnetic field. 3. Mantle plastic 4. Crust 5. Plates 6. Volcanism 7. Magnetic field due to currents in molten core II. Mercury A. Terrestrial planet 1. Similar to the Moon 2. Closest to Sun 3. Most elliptical orbit (used to be Pluto) 4. Smallest planet (used to be Pluto) 5. Second hottest planet in the system 623 K (day), 103 K (night) 1. Mass: kg 2. Radius: 2440 km 3. Atmosphere: none to speak of

2 III. IV. 4. Distance from Sun: AU 1/3 AU 5. Rotation period: 58.6 days 6. Revolution period: 0.24 year = 88 days 7. Solar day : 176 Earth days! C. Satellite - None 1. Solid core of iron 2. Core is largest fraction of its size of any planet in the system 3. Solid throughout 4. No volcanism 5. Craters and mountains Venus A. Terrestrial planet 1. Planet that comes closest to Earth 2. Nearest in size and mass to the Earth 3. Rotates backward retrograde 4. Covered with clouds sulfuric acid 5. Hottest planet in system due to greenhouse effect K 1. Mass: kg 2. Radius: 6000 km 3. Atmosphere: mostly carbon dioxide with traces of other gases 4. Distance from Sun: 0.72 AU 2/3 AU 5. Rotation period: 243 days - retrograde! 6. Revolution period: 0.62 year = 225 days C. Satellite - None 1. Interior similar to Earth 2. No magnetic field due to slow rate of rotation 3. No volcanism 4. Hills and continents Mars A. Terrestrial planet 1. Planet most nearly like the Earth in conditions 2. Nearly the same axial tilt as Earth so has seasons 3. Has polar icecaps 4. Rotation rate nearly the same as Earth 5. Rather cool 220 K 1. Mass: kg 2. Radius: 3400 km 3. Atmosphere: mostly carbon dioxide with traces of other gases

3 4. Distance from Sun: 1.5 AU 5. Rotation period: 24.5 hours 6. Revolution period: 1.9 years C. Satellite - Two 1. Deimos and Phobos 2. Small 3. Captured asteroids 1. Probably solid throughout maybe a little molten. 2. Small magnetic field 3. No volcanism 4. Olympus Mons highest mountain in the solar system 5. Valles Marineris deepest, widest, longest canyon in the system 6. Craters 7. Extinct volcanos 8. Dust storms V. Jupiter A. Gas Giant 1. Largest planet in the solar system 2. Most massive planet in system more massive that other planets combined. 3. Small axial tilt 4. Mostly hydrogen and helium 5. Rapid rotation rate 6. Cold 165 K at the cloud tops 7. Has rings but not as visible as are Saturn s 1. Mass: kg 2. Radius: 71,500 km 3. Atmosphere: about 85% H, 15% He, traces of other gases 4. Distance from Sun: 5.2 AU 5 AU 5. Rotation period: 10 hours 6. Revolution period: 11.9 years 12 years C. Satellite - Many 1. Largest Galilean moons of Jupiter a. Io (1) Mass: kg (2) Radius: 1800 km (3) Distance from Jupiter: 420,000 km (4) Revolution period: 1.77 days (5) Iron core, molten mantle, rocky crust, sulfur volcanos

4 VI. b. Europa (1) Mass: kg (2) Radius: 1600 km (3) Distance from Jupiter: 670,000 km (4) Revolution period: 3.55 days (5) Iron core, rocky mantle, ocean, icy crust (6) Maybe life! c. Ganymede (1) Largest moon in solar system (2) Mass: kg (3) Radius: 2600 km larger than Moon, Mercury! (4) Distance from Jupiter: 1,000,000 km (5) Revolution period: 7.2 days (6) Iron core, rocky mantle, icy mantle, icy crust d. Callisto (1) Mass: kg (2) Radius: 2400 km larger than Moon, Mercury! (3) Distance from Jupiter: 1,800,000 km (4) Revolution period: 16.7 days (5) ice/rock interior, ocean?, icy crust 2. Many smaller moons 3. Some captured asteroids 1. Interior a. Metal/rocky core b. Liquid metallic hydrogen c. Liquid molecular hydrogen and helium d. Gaseous hydrogen and helium 2. No definite surface gets thicker and thicker until solid 3. Huge magnetic field electric currents in metallic hydrogen 4. Huge storms Red Spot Saturn A. Gas Giant 1. Rings! 2. Second largest planet in the solar system 3. Low density would float in water. 4. Large axial tilt 5. Mostly hydrogen and helium 6. Rapid rotation rate 7. Cold 93 K at the cloud tops 1. Mass: kg

5 VII. 2. Radius: 60,000 km 3. Atmosphere: about 96% H, 3% He, traces of other gases 4. Distance from Sun: 9.6 AU 10 AU 5. Rotation period: 10 hours 6. Revolution period: 29.4 years 30 years C. Satellite - Many 1. Largest - Titan a. Second largest moon in the solar system b. Mass: kg c. Radius: 2600 km d. Distance from Saturn: 1,200,000 km e. Revolution period: 16 days f. Thick nitrogen atmosphere 2. Many smaller moons 1. Interior - similar to Jupiter a. Metal/rocky core about same size as Jupiter b. Liquid metallic hydrogen larger than Jupiter c. Liquid molecular hydrogen and helium smaller than J d. Gaseous hydrogen and helium larger than J 2. No definite surface gets thicker and thicker until solid 3. Large magnetic field electric currents in metallic hydrogen 4. Also storms but not as colorful as J due to lower T. Uranus A. Gas Giant 1. Rings but not visible 2. HUGE axial tilt 97! 3. Mostly hydrogen and helium 4. Medium rotation rate 5. Cold 55 K at the cloud tops 1. Mass: kg 2. Radius: 26,000 km 3. Atmosphere: about 83% H, 15% He, traces of other gases 4. Distance from Sun: 19.2 AU 20 AU 5. Rotation period: 17 hours 6. Rotation axis nearly in plane of its orbit 7. Revolution period: 84 years C. Satellites known 2. Most small; largest moderate in size

6 1. Interior a. Rocky core b. Compressed water c. Liquid hydrogen and helium 2. No definite surface gets thicker and thicker until solid 3. Also storms. VIII. Neptune A. Gas Giant - very similar to Uranus 1. Most distant planet from Sun 2. Rings but not visible 3. Large axial tilt Mostly hydrogen and helium 5. Medium rotation rate 6. Cold 55 K at the cloud tops 1. Mass: kg 2. Radius: 25,000 km 3. Atmosphere: about 80% H, 20% He, traces of other gases 4. Distance from Sun: 30 AU 5. Rotation period: 16 hours 6. Revolution period: 165 years C. Satellites known 2. Most small; largest moderate in size 1. Interior a. Rocky core b. Compressed water c. Liquid hydrogen and helium 2. No definite surface gets thicker and thicker until solid 3. Also storms. IX. Dwarf Planets A. A planet is defined to be an object that is large enough to coalesce into a sphere and to have cleared its orbit of other material. B. Under this definition, Pluto, which was a planet, is no longer considered to be one it lives in a region of ice objects called the Kuiper belt out beyond the orbit of Neptune. It is spherical but has not cleared its orbit. C. The new object 2003UB313 or Eris is larger than Pluto and would have been a planet if the definition hadn t been changed. D. There may be as many as 20 Pluto-sized objects out beyond Neptune, and astronomers wanted to keep the number of planets to a reasonable

7 size. E. Under this definition, Ceres and other large objects that had been asteroids are now dwarf planets as well. F. Notable Dwarf Planets 1. Pluto a. One of the largest members of the Kuiper belt. b. Charon its moon large in comparison to Pluto s size c. Huge tilt! 118 d. Cold 40 K e. Made of ices f. Mass kg g. Radius 1200 km h. Atmosphere (1) None to speak of except in summer when closest to Sun nitrogen and carbon monoxide (2) Shares its atmosphere with Charon (3) Double planet i. Distance from Sun 40 AU j. Rotation period (1) 6.4 days (2) Same as Charon s (3) Same as orbital period around each other (4) Doubly tidally locked k. Revolution period 250 years l. Surface: frozen nitrogen and CO m. Moons (1) Charon (a) Similar to Pluto (b) Surface water ice (2) Two other tiny moons 2. Eris 2003UB313 a. Similar to Pluto but larger b. Called Xena in house while analyzing after its discovery c. Has a moon that was called Gabrielle - Dysnomia. X. Vagabonds of the Solar System A. Asteroids 1. Too small to form as spheres 2. Most orbit Sun between Mars and Jupiter asteroid belt 3. Probably prevented from forming a planet by Jupiter s large gravitational field 4. Some exist elsewhere

8 a. Jupiter s Lagrange points Trojan asteroids b. Some cross Earth s orbit might hit us at some point c. Collisions with such objects in the past may have caused mass extinctions. 5. Composition mostly rock with some metal B. Comets 1. Dirty snowballs. 2. Highly elliptical orbits spend most of the time far from the Sun 3. Kuiper Belt and Oort Cloud 4. When close to Sun, heat sublimes gas from the comet creating a tail. 5. Two tails gas and dust 6. Directed away from Sun 7. May have provided Earth (and other planets) with water in the early solar system. 8. Also can collide with Earth to devastating effect C. Meteoroids, Meteors, and Meteorites 1. Meteoroid small object floating through space 2. Meteor small object in the process of burning up in the Earth s atmosphere 3. Meteorite small object that makes it through the Earth s atmosphere and hits the ground. 4. Meteor Showers debris left in orbit as comets move around intersect Earth s atmosphere creating as many as a meteor a second (rare) usually a meteor a minute or so. 5. Types of meteorites a. Stony (1) Look like ordinary rocks. (2) If you see an ordinary rock lying atop the snow in the arctic or antarctic, it s a stony meteorite. b. Iron easy to distinguish from ordinary rocks c. Stony-iron roughly equal amounts of stone and iron 6. Thought to come from asteroids a. Stony from exterior b. Iron from iron core c. Stony-Iron from boundary between core and exterior