Chapter 29 The Solar SystemChapter 29 The Solar System
The Planets
Overview of Our Solar SystemOverview of Our Solar System
M V E M J S U N P (Mercury, Venus,Earth, Mars, Jupiter, Saturn, Uranus,Neptune, Pluto) (My Very EnergeticMother Just Sent Us Nine Pizzas.)
All planets and their moons (satellites)orbit the Sun in the same direction.
All orbits lie in the same plane exceptPluto’s orbit.
Early IdeasEarly Ideas
•Planets slowly change position each nightrelative to the position of the stars.
•Geocentric Model – Use to think Earthwas the center and sun, stars, & planetsorbited us.
•Planets orbit to the east as viewed fromearth, but occasionally move in theopposite direction (RETROGRADEMOTION).
Early IdeasEarly Ideas
•Copernicus suggested that sun iscenter of solar system (HeliocentricModel)
•Earth and inner planets, which arecloser to sun move faster in orbits andpass up outer planets at certain pointsin their path making them appear tomove backwards.
Early IdeasEarly Ideas
•Kepler’s First Law = Planets orbit theSun in an ellipse, not a circle.
•1 Astronomical Unit (AU) – averagedistance between the sun and earth.(1.496 x 108 km) Other planets’ distancefrom sun is compared to that of the earth.
Early IdeasEarly Ideas
•Perihelion – point in ellipticalorbit when planet is closest tosun.
•Aphelion – point in ellipticalorbit when planet is farthestfrom sun.
Early IdeasEarly Ideas
•Galileo first person to use a telescope toobserve sky. (Saw 4 largest moons ofJupiter)
•Newton – studied gravity (attractive forcebetween two bodies that depends on theirmasses and the distance between the twomasses. Also found that each planetorbits a point between it and the sun calledthe center of mass, which is closest to theheaviest body.
Section 29.2 The TerrestrialPlanetsSection 29.2 The TerrestrialPlanets
•Inner four planets
•Close to size of earth
•Solid, rocky surfaces
•Mercury, Venus, Earth, Mars
The Solar SystemThe Solar System
•Planets
•InnerPlanets
•Terrestrial
•Mercury
•Venus
•Earth
•Mars
•OuterPlanets
•Gaseousgiants
•Jupiter
•Saturn
•Uranus
•Neptune
•Pluto
The Solar SystemThe Solar System
Section 29.2 The TerrestrialPlanetsSection 29.2 The TerrestrialPlanets
•Click here to see a movie about the innerplanets.
MercuryMercury
•No moons
•1/3 size of earth.
•Slow rotation (Its revolution(year) is 1/1/2 of its days!)
MercuryMercury
MercuryMercury
•No atmosphere
•Hot daytime 427 degrees Celsius; Coldnight –173 degrees Celsius. Largesttemperature difference of all the planets.
•Cratered surface with smooth lava createdwith lava flows similar to our moon.
•High density suggests a Nickel-Iron corewith molten interior.
Venus Venus
•No moons
•Brightest planet in our nighttime sky
•Covered with thick clouds of sulfuricacid
•Very hot
•Rotates slowly
•One day is 243 Earth days
Venus Venus
•Clockwise spin (opposite the spin of otherplanets) (Rises in west & sets in east)Retrograde motion
•Sister planet to Earth (most like earth indiameter, mass, density)
•Atmosphere of carbon dioxide whichcauses Greenhouse effect!
•Few impact craters; smooth surfaceindicates volcanic activity
•Internal structure probably similar to earth.
VenusVenus
EarthEarth
•Third rock from the sun
•Distance from sun allows water to exist assolid, liquid, & gas.
•Liquid water required for life
•Atmosphere is 78% nitrogen & 21 %oxygen supports life
•Mild greenhouse effect
•Tilted 23 ½ degrees on axis causesseasons
•Wobbles as it spins (precession) due togravitational pull of moon and sun.
EarthEarth
MarsMars
•Red planet (iron in soil)
•Smaller & less dense than earth
•2 moons (Phobos & Deimos)probably captured asteroids
•Atmosphere similar to Venus, withlower pressure and density & nogreenhouse effect.
MarsMars
•Windy; dust storms
•Southern surface is cratered; smoothnorthern surface with 4 giant shieldvolcanoes
•Dried river & lake beds suggest wateronce existed on Mars; has some carbondioxide ice (dry ice) at poles.
•Probably a solid nickel & iron core.
Mars = The Red PlanetMars = The Red Planet
The Inner PlanetsThe Inner Planets
•Let’s see how much you havelearned about the inner planets!
Section 29.3 The Gas GiantPlanetsSection 29.3 The Gas GiantPlanets
•Outer planets are gas giantscomposed of fluids, gases andsmall solid cores.
•H, He, C, N, O (all light weight)
•15 to 300 x mass of earth
•4 – 10 times the earth’s diameter
Section 29.3 The Gas GiantPlanetsSection 29.3 The Gas GiantPlanets
•Let’s see a movie about the outerplanets!
JupiterJupiter
•largest planet
•11 x larger diameter than earth & 10 xsmaller than sun
•70% of all planetary matter in solarsystem
•banded appearance (flow patterns inatmosphere)
•4 major moons + at least 12 smallerones
JupiterJupiter
•volcanic moon Io (Europa,Ganymede, Callisto) made of ice &rock
•H & He atmosphere
•10 hour rotation (shortest of anyplanet)
•Great Red Spot giant storm onsurface
•Has a ring
Jupiter’s Red Spot is a StormJupiter’s Red Spot is a Storm
SaturnSaturn
•2nd largest
•rotates rapidly for its size
•H & He atmosphere and ammonia clouds
•Extensive ring system made of rock & ice (7 major rings made of smaller ringlets)May have come from an asteroid thatcollided with planet.
•18 moons (Titan is larger than earth’smoon)
SaturnSaturn
UranusUranus
•Blue planet
•18+ moons & 10 rings (dark in color)
•methane atmosphere reflects bluelight (H & He)
•Rotates almost on its side
•May have been knocked sideways byan asteroid.
•Cold
UranusUranus
••Tilted on itsside.
NeptuneNeptune
•Slightly smaller than Uranus
•Blueish color due to methane atmosphere
•Great Dark Spot (storm ) similar toJupiter’s Red Spot disappeared in 1994
•8 moons (Triton is largest; retrogrademotion ; orbits backwards; has nitrogengeysers)
•6 rings made of dust particles
NeptuneNeptune
••The dark spotis a stormsimilar to theone on Jupiterbut not a large.
PlutoPluto
•solid surface, but not classified asterrestrial due to low density &small size.
•Made of half ice & half rock
•Smaller than earth’s moon
•Methane & nitrogen atmosphere
PlutoPluto
••Pluto’s onemoon Charonis shown in theupper leftcorner.
Outer PlanetsOuter Planets
•Let’s see how much you have learnedabout the outer planets: