Post on 11-May-2015
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Solar System FormationLACC: § 6.2, 6.3, 6.4
• Gravitational Contraction of a giant cloud of dust and gas
• Condensation
• Accretion w/ Differentiation
An attempt to answer the “big question”: how did we get here?
1Thursday, February 25, 2010
Nebular Hypothesis
http://www.youtube.com/watch?v=qfdDWdZcpOw2:15
2Thursday, February 25, 2010
Gravitational Contraction
http://eps.berkeley.edu/cig/depaolo/eps102/PPT5_Condensation_Accretion.html
What started outas a cloud of dust and gas light-years across, gravitationally collapsed to a solar nebula thousands of AU across.
(1 ly = 63,240 AU)
3Thursday, February 25, 2010
Gravitational Contraction
http://www.jwst.nasa.gov/birth.html
What started out as a cloud of dust and gas light-years across, gravitationally collapsed to a solar nebula thousands of AU across.
(1 ly = 63,240 AU)
4Thursday, February 25, 2010
http://woodahl.physics.iupui.edu/Astro100/08-T01.jpg
Solar Nebula:Composition
Note the typical condensation temperatures.
5Thursday, February 25, 2010
Protoplanetary Disks
http://burro.astr.cwru.edu/denise/Spring03/Mar27/Mar27.htm
Evidence for the Nebular Hypothesis: process is observed happening around other stars
6Thursday, February 25, 2010
http://eps.berkeley.edu/cig/depaolo/eps102/PPT5_Condensation_Accretion.html
Condensation then Accretion
7Thursday, February 25, 2010
http://boojum.as.arizona.edu/~jill/NS102_2006/Lectures/Lecture6/lecture6.html
The Frost Line and Condensation
8Thursday, February 25, 2010
Accretion
http://eps.berkeley.edu/cig/depaolo/eps102/PPT5_Condensation_Accretion.html
9Thursday, February 25, 2010
Solar System FormationLACC: § 6.2, 6.3, 6.4
• Gravitational Contraction of a giant cloud of dust and gas: Solar Nebula--98% H, He; flattens into a spinning disc
• Condensation: the colder the temperature, the greater the number and types of compounds that will condense
• Accretion w/ Differentiation: formation of planetesimals, many of which will combine to form planets
An attempt to answer the “big question”: how did we get here?
10Thursday, February 25, 2010
Formation of the PlanetsLACC: § 6.2, 6.3, 6.4
• Know the difference between terrestrial and gas giant planet: orbital distance, mass, size, density, composition, no. or moons
• Understand why there are terrestrial and gas giant planets: the frost line
• Understand the roles of the initial volatile molecules: CH4 (methane), NH3 (ammonia), H2O (water)
An attempt to answer the “big question”: how did we get here?
11Thursday, February 25, 2010
Planetesimals
http://www.youtube.com/watch?v=jhYEQgLW5NM&feature=related
Formation of the Solar System- Güneş Sistemi oluşumu
1:55
12Thursday, February 25, 2010
Making Planets
Inner Terrestrial (Earthlike)
• small w/ solid surface
• circular orbits w/ low eccentricities and inclinations
• high densities (about 5x water)
• atmospheres of N2 or CO2 (or no atmosphere at all)
Outer Jovian (Gas Giants)
• big balls of gas
• circular orbits w/ low eccentricities and inclinations
• low densities (about the same as water)
• thick atmospheres of H and He
13Thursday, February 25, 2010
Low e, Low Inclination Orbits
http://physics.lakeheadu.ca/courses/Astro/2310/PlanetGraphs/graphs.htm http://burro.astr.cwru.edu/denise/Spring03/Mar27/Mar27.htm
Eccentricity Orbital Inclinations
14Thursday, February 25, 2010
Eccentricities
http://burro.astr.cwru.edu/denise/Spring03/Mar27/Mar27.htm
Doesn’t count(dwarf planet)
15Thursday, February 25, 2010
Orbital Inclinations
http://burro.astr.cwru.edu/denise/Spring03/Mar27/Mar27.htm
Doesn’t count(dwarf planet)
16Thursday, February 25, 2010
Condensation then Accretion
http://physics.lakeheadu.ca/courses/Astro/2310/PlanetGraphs/graphs.htm
Near the sun, i.e. within the frost line, temperatures where higher (>150 K). Volatile materials, hydrogen compounds, remained gaseous and did not condense:
• water (H2O)
• ammonia (HN3)
• methane (CH4)
17Thursday, February 25, 2010
Surface Gravity and Solar uvSolar Nebula Composition
• 98% H, He
• 1.4% CH4, NH3, H2O
• rock 0.4%
• metals 0.2%
Note: Jovian planets had over three times as much material to build from--2.0% vs 0.6%
Jovian Planets
• Greater Mass = Greater Gravity
• They hold on to H, He becoming gas giants
Terrestrial Planets
• They can’t hold H, He
• Solar uv knocks H off of CH4, NH3, H20 leaving N2 and CO2
18Thursday, February 25, 2010
Terrestrial Planet Geology• Condensation
• Accretion w/ Differentiation
• Cooling during heavy bombardment
• Tectonic Plates during thin crust
• Mantle solidifies
• Interior Cools
Note: the smaller the planet it, the quicker it will cool.
• Mercury: smallest and has solid mantle
• Mars: smallish and had no significant geological activity in 3.5 billion years
• Venus: active volcanoes? resurfaced 0.5 billion years ago
• Earth: ongoing tectonic activity, e.g. volcanoes
19Thursday, February 25, 2010
LACC HW: Franknoi, Morrison, and Wolff, Voyages Through the Universe,
3rd ed.
• Ch. 6, pp. 150-151: #3. You should be able to list three easily, five with a little effort.
• Ch 7: Tutorial Quizzes accessible from: http://www.brookscole.com/cgi-brookscole/course_products_bc.pl?
fid=M20b&product_isbn_issn=9780495017899&discipline_number=19 Must Know: 1, 4, 9, 11, 12, 15, 16, 18, 19Important: 2, 3, 5, 10
Due at the beginning of next class period
20Thursday, February 25, 2010