Chapter 23 Our Solar System
 
23.1 The Solar System <ul><li>From Earth, other planets are just dots of light </li></ul><ul><ul><li>Tend to be mistaken f...
Heliocentric Model <ul><li>1543: Nicholas Copernicus (Polish  Astronomer) </li></ul><ul><ul><li>Proposed a series of diffe...
Modern View of the Solar System <ul><li>10 Planets revolve around our Sun </li></ul><ul><ul><li>Mercury, Venus, Earth, Mar...
Formation of the Solar System <ul><li>5 b.y.a. large cloud of gas, ice & dust existed </li></ul><ul><li>Began to contract ...
 
The Parts of Our Solar System <ul><li>The sun is the center of the Solar System </li></ul><ul><ul><li>Inner Planets:   Fir...
Motion of the Planets <ul><li>Johannes Kepler   studied planetary orbits </li></ul><ul><ul><li>Discovered orbits are   ell...
 
23.2 The Inner Planets <ul><li>Called  Terrestrial Planets </li></ul><ul><ul><li>First four planets:  Mercury ,  Venus ,  ...
Mercury: <ul><li>Closest planet to the Sun </li></ul><ul><ul><li>Revolution time:   88 days </li></ul></ul><ul><ul><li>Rot...
Venus: <ul><li>Second planet from the sun </li></ul><ul><ul><li>Revolution: 255 days </li></ul></ul><ul><ul><li>Rotation: ...
Earth: <ul><li>“ Third Rock from the Sun” </li></ul><ul><li>Average distance from the sun = 93,000,000 miles </li></ul><ul...
Mars: <ul><li>Fourth Planet from the Sun </li></ul><ul><li>“ The Red Planet ” </li></ul><ul><li>Surface mainly iron oxide ...
Discoveries on Mars <ul><li>Mariner 9  (1971–1972)   </li></ul><ul><ul><li>Discovered dried riverbeds </li></ul></ul><ul><...
 
Martian Moons <ul><li>Mars has small, crater riddled moons </li></ul><ul><ul><li>1)  Phobos:  25 km in diameter </li></ul>...
 
23.3 Mission to Mars <ul><li>How should Mars be explored? </li></ul><ul><ul><li>Travel time to Mars is a consideration </l...
23.4 The Outer Planets <ul><li>4 planets are gaseous giants  ( Jovian Planets ) </li></ul><ul><li>Last 2 are frozen sphere...
Jupiter: <ul><li>Largest Planet in our Solar System </li></ul><ul><li>Fifth planet in order </li></ul><ul><li>Revolution =...
 
Jupiter’s Moons <ul><li>Jupiter has at least 16 moons </li></ul><ul><ul><li>Four Largest =   Galilean Moons   (Discovered ...
Galilean Moons Io with eruption Europa Ganymede Callisto
Saturn: <ul><li>Sixth planet; 30 year orbit; 11 hr rotation </li></ul><ul><li>1980 & 1981 surveyed by the Voyagers </li></...
 
Uranus: <ul><li>Smallest of the gas planets  </li></ul><ul><li>Discovered in 1781 </li></ul><ul><li>7 th  planet, 84 year ...
Neptune: <ul><li>Last of the gas planets; discovered in 1846 </li></ul><ul><li>Orbit overlaps Pluto’s at 2 points </li></u...
Pluto: <ul><li>Discovered in 1930; smallest planetoid </li></ul><ul><li>Between 1979 & 1999 Pluto orbited inside Neptune <...
Xena: <ul><li>Discovered January 8 th , 2005 </li></ul><ul><ul><li>20 % larger than Pluto </li></ul></ul><ul><ul><li>Orbit...
Kuiper Belt <ul><li>Discovered by the Hubble Telescope </li></ul><ul><li>Vast disk of icy comets </li></ul><ul><li>Located...
Voyagers’ Continuing Mission <ul><li>After passing Saturn in 1980 Voyager 1 headed out of our Solar System </li></ul><ul><...
 
23.5 Other Solar System Objects <ul><li>Comets: </li></ul><ul><ul><li>Controlled by a star’s gravity </li></ul></ul><ul><u...
Comet Information: <ul><li>Comet Composition:  </li></ul><ul><ul><li>Dust, rock, frozen methane, ammonia, and water </li><...
Meteoroids, Meteors, & Meteorites <ul><li>Meteoroids:   chunks of rock </li></ul><ul><ul><li>Randomly moving through space...
LARGEST METEORITE TO HIT EARTH – Namibia, Africa
Largest US Meteorite – Kansas under 6 feet of earth.
Asteroids <ul><li>Large rocks located between Mars & Jupiter </li></ul><ul><ul><li>Asteroid belt: Large orbiting ring of a...
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Es Ch. 23 Solar System

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Es Ch. 23 Solar System

  1. 1. Chapter 23 Our Solar System
  2. 3. 23.1 The Solar System <ul><li>From Earth, other planets are just dots of light </li></ul><ul><ul><li>Tend to be mistaken for stars </li></ul></ul><ul><ul><li>Telescopes & space probes revealed so much more </li></ul></ul><ul><li>Early Ideas about the Solar System </li></ul><ul><ul><li>Earth Center Theory: </li></ul></ul><ul><ul><ul><li>Early Greeks believed Earth was the Center of the Universe </li></ul></ul></ul><ul><ul><ul><li>All objects were imbedded in circular paths around us </li></ul></ul></ul><ul><ul><li>Their order of the universe: </li></ul></ul><ul><li>Earth  Moon  Sun  Mercury  Venus  Mars  Jupiter  Saturn  Stars </li></ul>Pgs. 639 - 645
  3. 4. Heliocentric Model <ul><li>1543: Nicholas Copernicus (Polish Astronomer) </li></ul><ul><ul><li>Proposed a series of different views: </li></ul></ul><ul><ul><ul><li>The Earth is a planet </li></ul></ul></ul><ul><ul><ul><li>The moon revolves around the Earth </li></ul></ul></ul><ul><ul><ul><li>Planets revolve around the Sun </li></ul></ul></ul><ul><ul><ul><li>The apparent movement of the sun & planets is due to Earth rotating on it’s axis </li></ul></ul></ul><ul><ul><li>Galileo Galilei supported Copernicus </li></ul></ul><ul><ul><ul><li>Showed Venus goes through phases just like the moon </li></ul></ul></ul><ul><ul><ul><li>Only possible if Venus orbits the sun </li></ul></ul></ul>
  4. 5. Modern View of the Solar System <ul><li>10 Planets revolve around our Sun </li></ul><ul><ul><li>Mercury, Venus, Earth, Mars </li></ul></ul><ul><ul><li>Asteroid belt (separates inner & outer Planets) </li></ul></ul><ul><ul><li>Jupiter, Saturn, Uranus, Neptune, Pluto, Xena </li></ul></ul><ul><li>Most planets have at least one moon orbiting them </li></ul><ul><li>The sun contains 99.86 % of all solar system mass </li></ul><ul><li>Gravity controls motion and orbital paths </li></ul>
  5. 6. Formation of the Solar System <ul><li>5 b.y.a. large cloud of gas, ice & dust existed </li></ul><ul><li>Began to contract & slowly rotate </li></ul><ul><ul><li>Contraction increased density & rotation </li></ul></ul><ul><ul><li>Gravity began to pull material toward the center </li></ul></ul><ul><ul><li>Density increases = increased rotation & gravity </li></ul></ul><ul><ul><li>Begins to form disk with large center </li></ul></ul><ul><ul><li>Central mass begins to heat up due to contraction </li></ul></ul><ul><ul><ul><li>Temperatures reach 10 million 0 C </li></ul></ul></ul><ul><ul><ul><li>Hydrogen atoms begin to fuse together forming Helium </li></ul></ul></ul><ul><ul><ul><li>Fusion occurs, driving the formation of our Sun </li></ul></ul></ul><ul><ul><li>The material outside the central mass forms planets </li></ul></ul><ul><ul><li>This is known as the BIG BANG THEORY </li></ul></ul>
  6. 8. The Parts of Our Solar System <ul><li>The sun is the center of the Solar System </li></ul><ul><ul><li>Inner Planets: First four planets </li></ul></ul><ul><ul><ul><li>Solid, rock like structures </li></ul></ul></ul><ul><ul><li>Asteroid belt: band of rocks orbiting the sun </li></ul></ul><ul><ul><li>Outer Planets: Six planets farthest from the sun </li></ul></ul><ul><ul><ul><li>4 are made up of mainly lighter element gases </li></ul></ul></ul><ul><ul><ul><li>Last two are frozen materials </li></ul></ul></ul>
  7. 9. Motion of the Planets <ul><li>Johannes Kepler studied planetary orbits </li></ul><ul><ul><li>Discovered orbits are elliptical </li></ul></ul><ul><ul><ul><li>Farther from the sun, larger the ellipse </li></ul></ul></ul><ul><ul><ul><li>Realized the Sun is not exactly central in our solar system </li></ul></ul></ul><ul><ul><li>Planets travel at different speeds through their orbit </li></ul></ul><ul><ul><ul><li>Planets closer to the sun move faster </li></ul></ul></ul><ul><ul><ul><li>Planets change speed during their orbit as well </li></ul></ul></ul>
  8. 11. 23.2 The Inner Planets <ul><li>Called Terrestrial Planets </li></ul><ul><ul><li>First four planets: Mercury , Venus , Earth , Mars </li></ul></ul><ul><ul><li>All have a solid crust surface </li></ul></ul><ul><ul><li>Most have an atmosphere of some kind </li></ul></ul><ul><ul><li>Most have at least one moon </li></ul></ul>Pgs. 646 - 650
  9. 12. Mercury: <ul><li>Closest planet to the Sun </li></ul><ul><ul><li>Revolution time: 88 days </li></ul></ul><ul><ul><li>Rotation time: 59 days </li></ul></ul><ul><li>Third smallest planet </li></ul><ul><li>Probed by Mariner 10 (1974-1975) </li></ul><ul><ul><li>Imaged 45% of surface </li></ul></ul><ul><ul><li>Surface crater riddled (similar to our Moon) </li></ul></ul><ul><ul><li>Has large cliff lined valleys </li></ul></ul><ul><ul><li>Has a weak magnetic field (indicates iron core) </li></ul></ul><ul><ul><li>Very thin atmosphere: </li></ul></ul><ul><ul><ul><li>Hydrogen, Helium, Sodium & Potassium </li></ul></ul></ul><ul><ul><li>Surface Temperature: </li></ul></ul><ul><ul><ul><li>Daytime: 842 o F </li></ul></ul></ul><ul><ul><ul><li>Night: -274 o F </li></ul></ul></ul>
  10. 13. Venus: <ul><li>Second planet from the sun </li></ul><ul><ul><li>Revolution: 255 days </li></ul></ul><ul><ul><li>Rotation: Retrograde = spins backwards </li></ul></ul><ul><ul><li>Probed by Venera (Russian) in 1970 </li></ul></ul><ul><ul><li>Probed by Magellan (US) in 1990 to 1994 </li></ul></ul><ul><li>“ Earth’s Twin Sister” </li></ul><ul><ul><li>Size, Mass, Gravity similar to Earth </li></ul></ul><ul><li>Atmosphere: Thick & toxic </li></ul><ul><ul><li>Air Pressure = 90 times that of Earth </li></ul></ul><ul><ul><li>Mostly carbon dioxide </li></ul></ul><ul><ul><li>Clouds: Rain sulfuric acid </li></ul></ul><ul><ul><li>Only allow 2% of sunlight through to surface </li></ul></ul><ul><ul><ul><li>Solar energy trapped = extreme Greenhouse Effect </li></ul></ul></ul><ul><li>Surface temperature = 878 o F </li></ul><ul><ul><li>Surface covered by craters, fault lines, & Volcanoes </li></ul></ul><ul><ul><li>Winds = 300 km / hr. </li></ul></ul>
  11. 14. Earth: <ul><li>“ Third Rock from the Sun” </li></ul><ul><li>Average distance from the sun = 93,000,000 miles </li></ul><ul><li>Only planet water exists as 3 states of matter </li></ul><ul><ul><li>Solid, Liquid, & Gas </li></ul></ul><ul><li>Atmosphere protects the planet </li></ul><ul><ul><li>From meteor strikes (most burn up) </li></ul></ul><ul><ul><li>Intense Solar Radiation (UV, X-Rays, Gamma Rays, etc.) </li></ul></ul>
  12. 15. Mars: <ul><li>Fourth Planet from the Sun </li></ul><ul><li>“ The Red Planet ” </li></ul><ul><li>Surface mainly iron oxide dust (Rust) </li></ul><ul><li>Revolution time: 687 days </li></ul><ul><li>Has polar ice caps </li></ul><ul><ul><li>Northern: frozen Water (H 2 O) </li></ul></ul><ul><ul><li>Southern: frozen Carbon Dioxide (CO 2 ) </li></ul></ul>
  13. 16. Discoveries on Mars <ul><li>Mariner 9 (1971–1972) </li></ul><ul><ul><li>Discovered dried riverbeds </li></ul></ul><ul><ul><li>Olympus Mons: Largest know volcano in the Solar System </li></ul></ul><ul><ul><li>Rift Zones: Deep crustal tears </li></ul></ul><ul><li>Viking 1 & 2 (1976) </li></ul><ul><ul><li>Each consisted of Orbiter & Lander </li></ul></ul><ul><ul><li>Photographed entire Martian surface (Orbiters) </li></ul></ul><ul><ul><li>Studied meteorological, chemical, & biological aspects </li></ul></ul><ul><ul><ul><li>Discovered barren, rocky, windswept surface </li></ul></ul></ul><ul><ul><ul><li>Atmosphere: very thin; Carbon Dioxide, Nitrogen & Argon </li></ul></ul></ul><ul><ul><ul><li>Surface Temperatures: 95 o F (day) to -274 o F (night) </li></ul></ul></ul><ul><ul><ul><li>Temperature changes create intense winds & dust storms </li></ul></ul></ul><ul><ul><ul><li>NO evidence of life (past or present) </li></ul></ul></ul>
  14. 18. Martian Moons <ul><li>Mars has small, crater riddled moons </li></ul><ul><ul><li>1) Phobos: 25 km in diameter </li></ul></ul><ul><ul><ul><li>Slowly spiraling toward Mars </li></ul></ul></ul><ul><ul><ul><li>Expected impact of surface in 50 million years </li></ul></ul></ul><ul><ul><li>2) Deimos: 13 km in diameter </li></ul></ul><ul><li>Both are irregularly shaped </li></ul><ul><li>Both orbit Mars several times a day </li></ul>
  15. 20. 23.3 Mission to Mars <ul><li>How should Mars be explored? </li></ul><ul><ul><li>Travel time to Mars is a consideration </li></ul></ul><ul><ul><ul><li>Orbits at their closest = 1.5 years travel time </li></ul></ul></ul><ul><ul><ul><li>Orbits at their farthest = over 5 years travel time </li></ul></ul></ul><ul><ul><li>Length of travel time invites great risks to humans </li></ul></ul><ul><li>Should humans explore Mars? </li></ul><ul><ul><li>Humans do more meticulous & detailed work than probes </li></ul></ul><ul><ul><li>Zero gravity travel weakens muscles & bones </li></ul></ul><ul><ul><li>Body fluids move upward (increase kidney function) </li></ul></ul><ul><ul><li>Radiation exposure drastically increased </li></ul></ul><ul><li>Should robots explore Mars? </li></ul><ul><ul><li>Robots aren’t affected by 0 G’s; travel time not a factor </li></ul></ul><ul><ul><li>Robots using videotronics can be controlled from Earth </li></ul></ul><ul><ul><ul><li>Signals can have up to 20 min. delay </li></ul></ul></ul><ul><ul><ul><li>Robots cannot improvise & adapt to changing situations </li></ul></ul></ul>Pgs. 652 - 653
  16. 21. 23.4 The Outer Planets <ul><li>4 planets are gaseous giants ( Jovian Planets ) </li></ul><ul><li>Last 2 are frozen spheres </li></ul><ul><ul><li>Voyager 1 & 2 probed the 4 gaseous giants </li></ul></ul><ul><ul><ul><li>Jupiter, Saturn, Uranus, Neptune </li></ul></ul></ul>Pgs. 654 - 659
  17. 22. Jupiter: <ul><li>Largest Planet in our Solar System </li></ul><ul><li>Fifth planet in order </li></ul><ul><li>Revolution = 11.9 years to orbit </li></ul><ul><li>Rotation = 10 hrs. (fastest of all planets) </li></ul><ul><li>Voyager 1 & 2 (1979) probed Jupiter </li></ul><ul><ul><li>Gathered information about Jupiter’s Moons’ Atmospheres </li></ul></ul><ul><ul><li>Discovered 3 more moons </li></ul></ul><ul><ul><li>Discovered a faint dust ring orbiting Jupiter </li></ul></ul><ul><li>Jupiter’s Composition: </li></ul><ul><ul><li>Hydrogen, Helium, Ammonia, Methane, & water vapor </li></ul></ul><ul><ul><li>Gaseous Atmosphere, Liquid Mantle, & Solid Core </li></ul></ul><ul><ul><li>Clouds form color bands; Winds up to 400 km/hr. </li></ul></ul><ul><ul><li>Great Red Spot : Continuous Atmospheric Storm </li></ul></ul><ul><ul><li>Lightning has been observed in the atmosphere </li></ul></ul><ul><ul><li>Radiates 2x as much heat as it receives </li></ul></ul><ul><ul><li>Believed to be a star “that just didn’t make it” </li></ul></ul>
  18. 24. Jupiter’s Moons <ul><li>Jupiter has at least 16 moons </li></ul><ul><ul><li>Four Largest = Galilean Moons (Discovered in 1610) </li></ul></ul><ul><ul><ul><li>Io, Europa, Ganymede, Callisto </li></ul></ul></ul><ul><ul><li>Io: Closest of the Large moons to Jupiter </li></ul></ul><ul><ul><ul><li>Most volcanic objects in out Solar System </li></ul></ul></ul><ul><ul><ul><li>Sulfuric Lava produces Reddish/Orange color </li></ul></ul></ul><ul><ul><ul><li>Holds a thin sulfur dioxide atmosphere </li></ul></ul></ul><ul><ul><li>Europa: Composed of solid rock covered with ice </li></ul></ul><ul><ul><ul><li>Tectonic activity </li></ul></ul></ul><ul><ul><ul><li>Thin oxygen atmosphere </li></ul></ul></ul><ul><ul><li>Ganymede: Largest moon in the Solar System </li></ul></ul><ul><ul><ul><li>Larger than Mercury, Surface covered in Ice </li></ul></ul></ul><ul><ul><ul><li>Slushy Mantle, Solid rock core </li></ul></ul></ul><ul><ul><li>Callisto: Composed of heavily cratered Rock/Ice Crust </li></ul></ul><ul><ul><ul><li>Water/Ice mantle with a rocky core </li></ul></ul></ul>
  19. 25. Galilean Moons Io with eruption Europa Ganymede Callisto
  20. 26. Saturn: <ul><li>Sixth planet; 30 year orbit; 11 hr rotation </li></ul><ul><li>1980 & 1981 surveyed by the Voyagers </li></ul><ul><ul><li>“ Ringed Planet” </li></ul></ul><ul><ul><li>Second Largest planet </li></ul></ul><ul><ul><li>Very low density (would float in water) </li></ul></ul><ul><li>Atmospheric composition: </li></ul><ul><ul><li>Mostly hydrogen & helium; also ammonia, methane </li></ul></ul><ul><ul><li>Liquid Hydrogen/helium mantle </li></ul></ul><ul><ul><li>Small rocky core </li></ul></ul><ul><li>Rings composed of 100’s of ringlets </li></ul><ul><ul><li>Ringlets are made up of ice & rock particles </li></ul></ul><ul><li>At least 18 moon orbit Saturn (Most of any planet) </li></ul><ul><ul><li>Largest moon = Titan (2 nd largest in Solar System) </li></ul></ul><ul><ul><ul><li>Real atmosphere of nitrogen, argon, & methane </li></ul></ul></ul><ul><ul><ul><li>Thick, smog clouds cover Titan </li></ul></ul></ul><ul><ul><ul><li>Surface temp. = -180 0 C (-292 o F) </li></ul></ul></ul>
  21. 28. Uranus: <ul><li>Smallest of the gas planets </li></ul><ul><li>Discovered in 1781 </li></ul><ul><li>7 th planet, 84 year orbit, 17 hour rotation ** </li></ul><ul><li>Average Temp. = -328 o F </li></ul><ul><li>Voyager 2 surveyed (1986) </li></ul><ul><ul><li>Discovered 10 unknown moons (making 15 total) </li></ul></ul><ul><ul><ul><li>5 largest almost identical </li></ul></ul></ul><ul><ul><ul><li>Dark color, lack atmosphere, crater riddled </li></ul></ul></ul><ul><ul><li>Discovered several dark rings </li></ul></ul><ul><ul><li>Detected a magnetic field tilted 60 0 from axis </li></ul></ul><ul><ul><li>Atmosphere: Hydrogen, Helium & Methane </li></ul></ul><ul><ul><ul><li>Methane gives planet a blue/green tint </li></ul></ul></ul><ul><ul><ul><li>Liquid mantle of water, methane, & ammonia </li></ul></ul></ul><ul><ul><ul><li>Rocky core </li></ul></ul></ul><ul><ul><li>** Rotational axis lays on its side (spins like a tire) </li></ul></ul>
  22. 29. Neptune: <ul><li>Last of the gas planets; discovered in 1846 </li></ul><ul><li>Orbit overlaps Pluto’s at 2 points </li></ul><ul><ul><li>Change position 8  9 & 9  8 </li></ul></ul><ul><ul><li>1 orbit = 165 years; 1 rotation = 16 hrs </li></ul></ul><ul><li>Atmosphere: Hydrogen, Helium, Methane </li></ul><ul><ul><li>Methane gives Neptune bluish tint </li></ul></ul><ul><ul><li>Winds = 2200 km/hr; Temperature = -417 0 F </li></ul></ul><ul><ul><li>Has a dark spot = storm in it’s atmosphere </li></ul></ul><ul><ul><li>Liquid mantle: water, methane, & ammonia </li></ul></ul><ul><ul><li>Core: solid rock </li></ul></ul><ul><li>Voyager 2 detected 6 moons (Totaling 8) </li></ul><ul><ul><li>Largest moon = Triton </li></ul></ul><ul><ul><ul><li>Has a thin nitrogen atmosphere </li></ul></ul></ul><ul><ul><ul><li>Constantly erupting methane geysers </li></ul></ul></ul><ul><ul><li>Neptune also has rings (thin & thicken at different places) </li></ul></ul>
  23. 30. Pluto: <ul><li>Discovered in 1930; smallest planetoid </li></ul><ul><li>Between 1979 & 1999 Pluto orbited inside Neptune </li></ul><ul><ul><li>Rest of the time the ninth planet </li></ul></ul><ul><ul><li>Orbit = 248 years </li></ul></ul><ul><ul><li>Has a different orbital plane (tilted 17 0 from other planets) </li></ul></ul><ul><li>Surrounded by a minimal atmosphere </li></ul><ul><ul><li>Temperature = -364 o F </li></ul></ul><ul><li>Solid rocky crust </li></ul><ul><li>One Moon, Charon (½ diameter of Pluto) </li></ul><ul><ul><li>Orbits very close to Pluto </li></ul></ul><ul><ul><li>Sometimes considered “a double planet” with Pluto </li></ul></ul>
  24. 31. Xena: <ul><li>Discovered January 8 th , 2005 </li></ul><ul><ul><li>20 % larger than Pluto </li></ul></ul><ul><ul><li>Orbital time unknown; Rotational time unknown </li></ul></ul><ul><ul><li>Has one known moon </li></ul></ul><ul><ul><li>Dark & cold (below -225 0 C or -373 o F) </li></ul></ul><ul><ul><li>Has not been “officially” named yet </li></ul></ul>
  25. 32. Kuiper Belt <ul><li>Discovered by the Hubble Telescope </li></ul><ul><li>Vast disk of icy comets </li></ul><ul><li>Located near Neptune’s orbit </li></ul>
  26. 33. Voyagers’ Continuing Mission <ul><li>After passing Saturn in 1980 Voyager 1 headed out of our Solar System </li></ul><ul><li>After passing Pluto in 2000 Voyager 2 headed out of our Solar System </li></ul><ul><li>Both are still transmitting information back to Earth about deep space, and our sun’s long range influence of charged particles </li></ul>
  27. 35. 23.5 Other Solar System Objects <ul><li>Comets: </li></ul><ul><ul><li>Controlled by a star’s gravity </li></ul></ul><ul><ul><li>Travel through planets’ orbits, out of the Solar System, & back in again </li></ul></ul><ul><ul><li>HALLEY’S COMET: Most famous (last seen 1986) </li></ul></ul><ul><ul><ul><li>Returns every 76 years </li></ul></ul></ul><ul><ul><ul><li>Will return in 2062 </li></ul></ul></ul><ul><ul><li>HALE-BOPP: Most recent comet </li></ul></ul><ul><ul><ul><li>Discovered in July 23, 1995 </li></ul></ul></ul><ul><ul><ul><li>Visible from Earth during 1997 </li></ul></ul></ul>Pgs. 662 - 666 Halley’s Comet Hale-Bopp Comet
  28. 36. Comet Information: <ul><li>Comet Composition: </li></ul><ul><ul><li>Dust, rock, frozen methane, ammonia, and water </li></ul></ul><ul><ul><li>Comets normally look like dirty snowballs </li></ul></ul><ul><ul><li>When they get close to stars, they change </li></ul></ul><ul><ul><ul><li>They begin to vaporize & Glow </li></ul></ul></ul><ul><ul><ul><li>Forms a coma (tail) from the nucleus (head) </li></ul></ul></ul><ul><ul><ul><ul><li>Coma: glowing trail of particles </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Always points away from the star </li></ul></ul></ul></ul><ul><ul><li>Comets eventually break up into space debris </li></ul></ul><ul><li>Oort Cloud: large collection of comets beyond Pluto </li></ul>
  29. 37. Meteoroids, Meteors, & Meteorites <ul><li>Meteoroids: chunks of rock </li></ul><ul><ul><li>Randomly moving through space </li></ul></ul><ul><ul><li>Usually leftover comet or asteroid debris </li></ul></ul><ul><li>Meteor: Meteoroid that enters Earth’s atmosphere </li></ul><ul><ul><li>Heat up & begin to glow = shooting star </li></ul></ul><ul><ul><li>Most burn up before reaching the surface </li></ul></ul><ul><ul><li>Many meteors at one time = meteor shower </li></ul></ul><ul><li>Meteorite: Meteor that does not totally burn up, & strikes the Earth’s surface </li></ul><ul><ul><li>Impact creates a crater </li></ul></ul>
  30. 38. LARGEST METEORITE TO HIT EARTH – Namibia, Africa
  31. 39. Largest US Meteorite – Kansas under 6 feet of earth.
  32. 40. Asteroids <ul><li>Large rocks located between Mars & Jupiter </li></ul><ul><ul><li>Asteroid belt: Large orbiting ring of asteroids </li></ul></ul><ul><ul><li>Believed to be a planet that never formed </li></ul></ul><ul><ul><li>Range in size from dust to Moon size </li></ul></ul><ul><ul><ul><li>Some Named Asteroids: </li></ul></ul></ul><ul><ul><ul><ul><li>Ceres: 940 km (Largest known) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Pallas: 523 km </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Vesta: 501 km </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Juno: 244 km </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Gaspra & Ida: </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Photographed by Galileo probe </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Ida even has a smaller asteroid orbiting it </li></ul></ul></ul></ul>
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