Chapter 6 The Solar System

Planet Comparisons Property Terrestrial Planets Jovian Planets Distance CloseFar from the Sun Size SmallLarge Mass SmallLarge CompositionRockySolar-like DensityHighLow

Relative Sizes

JUPITER Earths 11 Earths can fit across Jupiter’s equator.

Formation of the Solar System n The solar system formed from a cloud of gas and dust in a process known as accretion.

n During the first few million years, matter in the accretion disk of our proto-sun coalesced into larger objects called planetesimals, with diameters of about 100 km.

Username: astro Password: mars Some resources compliments of Mcgraw-Hill

n We see evidence of accretion disk around other stars. For example,  Pictoris. For example,  Pictoris.

n Collisions of planetesimals dominated the early solar system and these objects combined to form our planets. n We see evidence of early collisions in our solar system in the form of impact craters on the planets and their moons.

n In addition to the 9 major planets, there are at least 65 moons in our solar system. n While some of these moons are spherical, most look roughly like potatoes. n There is still minor debris left over from the formation of the solar system: asteroids and comets.

Bode’s Law n a simple rule that gives the distances of the planets from the Sun where N=0, 3, 6, 12, 24…for Mercury, Venus, Earth, Mars, etc.

____24(24+4)/10 = 2.8 AU_______ Planet N Bode’s Law Radii True Orbital Radii Mercury0(0+4)/10 = 0.4 AU0.39 AU Venus3(3+4)/10 = 0.7 AU0.72 AU Earth6(6+4)/10 = 1.0 AU1.00 AU Mars12(12+4)/10 = 1.6 AU1.52 AU Jupiter48(48+4)/10 = 5.2 AU5.2 AU Saturn96(96+4)/10 = 10.0 AU9.5 AU Uranus192(192+4)/10 = 19.6 AU19.2 AU Neptune??30.1 AU Pluto384(384+4)/10 = 38.8 AU39.5 AU Ceres AU

What does Bode’s Law tell us? n Bode's Law predicted that there should be a planet between the orbits of Mars and Jupiter. n The "missing planet" turned out to be the asteroid belt.

Arizona Meteor Crater Approximately 1 mile across

Arizona Meteor crater superimposed over a map of NYC

Odessa, Texas

500 ft wide

Exploration of the Solar System

Mariner Missions Exploration of Mercury and Venus

ProbeMission Mariner 4 (1965) Mars Mariner 10 ( ) Mercury Mariner 6&7 (1969) Mars Mariner 9 (1971) Mars Viking 1&2 ( ) Mars Mars Observer (1993) Mars Mars Global Surveyor ( 1996) Mars Pathfinder/Sojourner (1998) Mars Pioneer & Voyager (1970s) Jovian Planets Galileo (1989) Jupiter

The Viking Lander – Mojave Desert prior to launch

View of the Martian Surface by Viking I

More recently, the Mars rover “Sojourner” analyzes a Martian rock in 1997.

Voyager Missions –Explore the Outer Planets

Photograph of Jupiter’s Red spot taken by Voyager I

Go To videos – Galileo flybys from JLP Galileo was another probe that studied Juipiter extensively.

n Planets outside of our solar system have been found recently using Doppler shifts in the spectra of some stars.

End of Section. The End.

Matching n 1. Reddish color of Mars n 2. Red-orange color of Jupiter's belts n 3. Venus' yellowish clouds n 4. Blue-green color of the surface of Uranus and Neptune n 5. The yellow and orange color of Io n a. ammonia clouds n b. sulfur powder n c. sulfuric acid clouds n d. methane clouds n e. iron

Matching n 6. Has an almost featureless surface n 7. The brightest planet seen from Earth n 8. The most distant planet in 1996 n 9. Last planet in our solar system to be discovered n 10. A possible fossil of single-cell life was found on a meteorite from this planet n a. Sun n b. Mercury n c. Venus n d. Earth n e. Mars n f. Jupiter n g. Saturn n h. Uranus n i. Neptune n j. Pluto