Touring Our Solar System Chapter 23
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. Overview of the Planets Terrestrial planets: small and rocky Jovian planets: huge gas giants
How long is Jupiter’s “year”? How long is Mercury’s “year?
23.1 The Solar System Interiors of the Planets Classes: (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 Theory Sun and planets formed from a rotating disk of gas and dust. Planetesimals collided and built the planets and become round.
23.2 Terrestrial Planets Mercury: Smallest planet (no atmosphere) Dense with many craters Scraps from cooling Temperature:-173 to 427oC 59 earth-day rotation 88 earth-day revolution
23.2 Terrestrial Planets 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 Planets Mars: Polar caps made of CO2 Large long dust storms Most atmosphere escaped Olympus Mons- 23 km high Valles Marineris
23.2 Terrestrial Planets Mars: Rovers discovered marks of liquid water on Mars
23.3 Outer Planets (and Pluto) Jupiter: Giant Among Planets 1/800 of Sun Mass 2.5x 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- volcanic Eurpoa- fractured icy surface Ganymede- largest, parallel groves Callisto- many craters
23.3 Outer Planets (and Pluto) Jupiter: Rings: Very faint Maybe fragments of 2 smaller moons
23.3 Outer Planets (and Pluto) Saturn: Rings: Main feature 100 m thick
23.3 Outer Planets (and Pluto) Saturn: Moons: 56 currently Titan – largest Atmosphere and 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 Planet 1000km/hr Great Dark Spot: Storm like Giant red Spot. Vanished! Repapered. Methane clouds. Triton –retrograde and volcanic
23.3 Outer Planets (and Pluto) Pluto: Dwarf Planet Fails to attract object in its orbit. (clearing its orbit) 228 years Charon-moon
23.4 Minor Members NEAR Shoemaker Landed on asteroid Eros Very low gravity Most asteroids are between Mars and Jupiter.
23.4 Minor Members Comets Made of rocks, frozen water, methane, carbon dioxide and carbon monoxide. Very elongated orbits. Tail points away from the sun.
23.4 Minor Members Comets Many short period come from the Kuiper Belt Long period come from the Oort Cloud
23.4 Minor Members Comets Halley’s Comet 1986 Giotto probe passed within 600 km 8 km x 16 km
23.4 Minor Members Meteoroids Small solid particles 3 sources: interplanetary debris asteroid belt comet remains Meteors-burn up in contact with atmosphere. Meteorites- reaches Earth
23.4 Minor Members Meteoroids Age of meteorites are about 4.567 billion years old. Made mostly of iron. Meteor Showers- annual event from comet passes across Earth’s orbit.