23.1 The Solar System
99.85% of the mass of our solar system is in the Sun, planets make up the rest.
Gravity holds planets in orbit.A. Overview of the Planets
Terrestrial planets: small and rockyJovian planets: huge gas giants
23.1 The Solar System
Interiors of the PlanetsClasses: (based on melting
point)gases: H and He (-273oC)rocks: silicate and iron (> 700oC)ices: ammonia, methane, carbon dioxide, and water. (between others)
23.1 The Solar System
Atmosphere of the Planets
Planets can only have an atmosphere if gravity is great enough.
Ex: Earth: 11 km/s escape velocity.
He and H escape from Earth.
23.1 The Solar System
B. Formation of solar System.
Nebular TheorySun and planets formed from a rotating disk of gas and dust.
Planetesimals collided and built the planets and become round.
23.2 Terrestrial Planets
A. Mercury:Smallest planet (no atmosphere)Dense with many cratersScraps from coolingTemperature:-173 to 427oC59 earth-day rotation88 earth-day revolution
23.2 Terrestrial PlanetsB. Venus:255 Earth-day “year”Thick crushing atmosphere (97%
carbon dioxide) 90x pressure Temperture-475oC
Radar maps shows basaltic volcanism and tectonic activity.
Most flat plains with few mountains.
23.2 Terrestrial PlanetsC. Mars:Polar caps made of CO2
Large long dust stormsMost atmosphere escapedOlympus Mons- 23 km highValles Marineris
23.3 Outer Planets (and Pluto)Jupiter: Giant Among Planets1/800 of Sun Mass2.5x greater then all others
planets together.Great Red Spot- seen cyclonic
storm seen Giovanni Cassini about 1690.
Structure: pressure to make hydrogen into a liquid.
May have rocky core.
23.3 Outer Planets (and Pluto)Jupiter:Moons:Io- volcanicEurpoa- fractured icy surfaceGanymede- largest, parallel
grovesCallisto- many craters
23.3 Outer Planets (and Pluto)Saturn:Moons:56 currentlyTitan – largest
Atmosphereand hydrocarbon seas
Enceladus-volcanic and water geysers
23.3 Outer Planets (and Pluto)Uranus: Planet on its
side.
Winking star was a sign of a ring (9)
Miranda
23.3 Outer Planets (and Pluto)Neptune: Windy Planet1000km/hrGreat Dark Spot: Storm
like Giant red Spot.Vanished! Repapered.Methane clouds.Triton –retrograde and
volcanic
23.3 Outer Planets (and Pluto)Pluto: Dwarf PlanetFails to attract object
in its orbit. (clearing its orbit)
228 yearsCharon-moon
23.4 Minor MembersNEAR ShoemakerLanded on asteroid
ErosVery low gravityMost asteroids are
between Mars and Jupiter.
23.4 Minor MembersCometsMade of rocks, frozen
water, methane, carbon dioxide and carbon monoxide.
Very elongated orbits.Tail points away from
the sun.
23.4 Minor MembersCometsMany short period
come from the Kuiper Belt
Long period come from the Oort Cloud
23.4 Minor MembersMeteoroidsSmall solid particles3 sources:
interplanetary debrisasteroid beltcomet remains
Meteors-burn up in contact with atmosphere.
Meteorites- reaches Earth