Bit of Administration …. ReadingReading –BSNV Chaps. 9 and 15 No Mathieu office hours today (Monday)!No Mathieu office hours today (Monday)! Additional observations for Lab 2, through April 5Additional observations for Lab 2, through April 5 –Due April 7 in lecture or April 9 at Mathieu office 12-week exam in two weeks - April 12, 7:15 pm12-week exam in two weeks - April 12, 7:15 pm –Review session, Sunday, April 11, 6:30 pm

The Solar System A Sense of Scale A Sense of Scale

The Solar System A Sense of Scale A Sense of Scale

The Solar System A Sense of Scale A Sense of Scale

The Solar System Inventory Inventory Sun99.85% by mass Sun99.85% by mass Planets 0.1 % by mass Planets 0.1 % by mass Satellites and Rings Satellites and Rings Asteroids Asteroids Comets Comets Meteroids Meteroids Dust Dust Solar Wind (ionized gas) Solar Wind (ionized gas)

The Solar System Inventory - “Sedna” Inventory - “Sedna”

The Solar System General Characteristics of Major Planets - Dynamical General Characteristics of Major Planets - Dynamical Nearly circular orbits (Mercury and Mars most eccentric) Nearly circular orbits (Mercury and Mars most eccentric)

The Solar System General Characteristics of Major Planets - Dynamical General Characteristics of Major Planets - Dynamical Nearly circular orbits (Mercury and Mars most eccentric) Nearly circular orbits (Mercury and Mars most eccentric) All orbit within 10 o of Earth’s orbital plane All orbit within 10 o of Earth’s orbital plane

The Solar System General Characteristics of Major Planets - Dynamical General Characteristics of Major Planets - Dynamical Nearly circular orbits (Mercury and Mars most eccentric) Nearly circular orbits (Mercury and Mars most eccentric) All orbit within 10 o of Earth’s orbital plane All orbit within 10 o of Earth’s orbital plane All revolve in the same direction All revolve in the same direction All rotate in the same direction (except Venus) All rotate in the same direction (except Venus)

The Solar System General Characteristics of Major Planets - Radius General Characteristics of Major Planets - Radius

The Solar System General Characteristics of Major Planets - Age General Characteristics of Major Planets - Age Earth - Oldest rocks 3.9 billion yr (4.5 billion yr inferred) Earth - Oldest rocks 3.9 billion yr (4.5 billion yr inferred) Moon billion yr Moon billion yr Meteorites billion yr Meteorites billion yr Sun billion (theoretical) Sun billion (theoretical) Universe - 12 billion yr Universe - 12 billion yr

The Solar System General Characteristics of Major Planets - Physical Properties General Characteristics of Major Planets - Physical Properties Terrestrial Terrestrial Location Inner Size Small (10 4 km) Mass M Earth Density 5 gm cm -3 Appearance Rock with craters, volcanos volcanos Composition Heavy elements 7 Giant Satellites Outer Small (4000 km) 0.01 M Earth 2-3 gm cm -3 Rock, ice with craters, volcanos Heavy elements, ices JovianOuter Large (10 5 km) M Earth 1 gm cm -3 Gaseous, with rock cores Hydrogen, helium Mercury Venus Earth Mars Jupiter Saturn Uranus Nepture Notes: 1)Densities: Rock = 3 gm cm -3, Water = 1 gm cm -3 2)Composition of Sun and Universe by numbers of atoms: 94% H, 6% He, 2% all else 94% H, 6% He, 2% all else Io Europa Ganymede Callisto

The Formation of the Solar System

Interstellar Clouds Interstellar Clouds By Mass 73% Molecular Hydrogen 73% Molecular Hydrogen 25%Atomic Helium 25%Atomic Helium 2% Dust (Metals) 2% Dust (Metals)

The Taurus clouds are thought to be rather cold, with temperatures of perhaps 30 K. If you wanted to test this hypothesis by looking for light emitted by the Taurus clouds, in what wavelength would you want to observe? A) X-ray A) X-ray B) Ultraviolet B) Ultraviolet C) Optical C) Optical D) Infrared D) Infrared E) Radio E) RadioConcepTest!

The Formation of the Solar System Dense Molecular Cores Dense Molecular Cores (“Bok Globules”) (“Bok Globules”) ≈ 1 M o ≈ 1 M o ≈ 50,000 AU ≈ 50,000 AU ≈ 10 o K ≈ 10 o K

The Formation of the Solar System

Protoplanetary Disks Protoplanetary Disks ≈ 0.01 M o ≈ 0.01 M o ≈ 100 AU ≈ 100 AU ≈ > 10 o K ≈ > 10 o K

The Formation of the Solar System

Condensation Sequence Condensation Sequence Condensation Temperature Condensation Temperature Temperature at which Solid Gas T > 50 o K T > 200 o K T > 1000 o K Hydrogen (H) Helium (He) H 2 0, Methane (CH 4 ) CO 2, Ammonia (NH 3 ) Iron (Fe), Silicon (Si) Metal Compounds Gas Gas Gas Ice Gas Gas Rock Rock Gas

The Formation of the Solar System Condensation Sequence Condensation Sequence 1000 K 200 K Rock Grains Rock, Ice Grains No Grains M M JE V

The Formation of the Solar System

Grain Collisions ==> Planetesimals (100 km) Grain Collisions ==> Planetesimals (100 km) random random 100 km

The Formation of the Solar System Planetesimal Accretion ==> Rocky Planets and Jovian Cores Planetesimal Accretion ==> Rocky Planets and Jovian Cores gravity gravity

The Formation of the Solar System Gas Accumulation ==> H and He onto Jovian Cores Gas Accumulation ==> H and He onto Jovian Cores gravity gravity Protomoons

Most comets have orbits that take them well beyond Jupiter. You would expect their composition to be: A) Rocks and heavy elements only A) Rocks and heavy elements only B) Rocks and ices only B) Rocks and ices only C) Rocks, ices, and hydrogen and helium C) Rocks, ices, and hydrogen and helium ConcepTest!

The Formation of the Solar System

Dispersal of Hydrogen and Helium Gas Dispersal of Hydrogen and Helium Gas Solar Wind? Solar Wind? Jets? Jets?