Venus-size nearly identical as Earth, rotates slow&opposite direction of Earth. Dense clouds->
extreme greenhouse effect->hot as pizza oven.
Mars-frozen CO2,evidence of river beds etc.
Jupiter-mass 300xEarth. Volume1000x. Many moons, faint rings. Great red spot-long lived storm
-no solid surface. Helium&Hydrogen. 4 Galileon moons-Io-volcanic Europa-icy
Saturn-lower density less massive. Helium&Hydrogen gas ,no solid surface. Rings-countless small
particles orbits Saturn. Spacecraft-cassini goes there to observe Saturn.
Uranus-H,He,H2O ammonia&methane.-Blue. Lack solid surface. Tipped on side-extreme season v.
Neptune-More blue. Moon (Triton) orbits backward.
Pluto-dwarf planet.ice+rock. Different class.located in Kuiper belt.
Patterns of motion among large bodies-planetary orbits nearly circular&lie nearly in same plane
-planets orbit sun in same direction(counterclockwise)
-most planets rotate in same direction in which they orbit,w/
small axis tilt.(including sun)
-moon orbits planet's equatorial plane.
Two types of planets-terrestrial planets-four inner planets-small,dense,rocky surface,metals in cores
few moons,no rings.
-jovian planets-four larger planets.low density,rings,numerous moons,Helium
hyrogen,ammonia, methane.gas giants.
Asteroids&comets-vast numbers,orbit sun.Asteroid-rocky, small, found w/in asteroid belt. Comets-
ice&rock,beautiful tails, few visit inner solar sys.and remain far fr sun w/out tails
-kuiper belt-beyond orbit of Neptune,contains 100000icy objects, oort cloud-
Exception to the rule-Uranus rotates almost on its side,Venus rotates backwards,some moon have
unusual orbits, Earth has a large moon.
Flyby-goes past world once and continue on its way. Obiter-orbits the world ,allow long-term study
Lander/probe-land on planets surface. Sample return mission-returns to Earth carrying sample.
Nebula theory-solar sys born fr a cloud of gas(solar nebula),collapsed under gravity. It began as a
large spherical cloud,cold, low-density gas,spread out in few light-yrs diameter,as it
collapse,shrank in size.3 processes altered density,temp,shape,cloud->spinning disk
1Heating-temp of solar nebula increase,shrank->gravitational potential energy->kineti
ic energy of gas particles,collide-> thermal energy, sun formed->highest temp&dense
2Spinning-solar nebula rotate faster as it shrank in radius->conservation of angular
momentum.more the momentum, more spread out it wud be, not everything in centre
3Flattening-natural consequence of collision b/w particles in a spinning cloud,
Testing model-heating occurs->gas emit thermal radiation-we detected infrared radiation.
Why two types of planets?particles condense out of gas form planets. Ingredients in solar nebula:
-Hydrogen&helium gas;Hydrogen compounds(condense into ice beyond frost line);Rock;Metal.
-Frost line-distance which is cold enough for ice to condense.marks transition b/w warm/cool region
inside frost line only metal&rocks condense,beyond-hydrogen compound condense
Terrestrial planets form-accretion-microscopic particles orbit around sun,collide with neighbor,but
too small to attract each other,they cud stick tog thru electrostatic forces->
same as “static electricity”(hair stick to comb)->small particles->big ones->
gravity aids and form planetesimals(pieces of planets).
Jovian planets form-Accretion,but more amounts of ice than rocks and metals.had more gravity.
Wat ended planet formation-most gases swept into interstellar space by radiation fr sun&solar wind.
Sun rotates slow now->because of solar wind swept particles away->lose angular momentum.
Where asteroids&comets come fr?-as sweep excess gas fr solar nebula,many planetesimals remain
scattered,leftovers become asteroids/comets.Asteroids are rocky
leftovers,comets-ice rich,some qualify as dwarf planets.