ASTR 241: Class Log

1. Solar System Overview

The first week introduces key elements of the Solar System, including the Sun, terrestrial and giant planets, smaller bodies, and the solar environment. Planetary motion and Kepler's laws are discussed in detail.

Handouts: Syllabus, Discussion Question.

Slides: Solar System Overview.

Board: Geometry of Ellipse, Kepler's Laws, Falling into Orbit [26 Aug], Problem #2, Problem #3 [28 Aug].

Assignment: Problem Set #1: Due 31 Aug 2015. Problem #4 is optional.

2. Orbital Motion

This week covers the derivation of Kepler's Laws from Newtonian mechanics, bound vs. unbound orbits, and the general 2-body problem.

Board: Kepler Problem, Conservation of Angular Momentum, Polar Coordinates, Shape of Orbit [31 Aug], Orbits & Conic Sections, Orbit Period, Kepler's Equation, Solving Kepler's Equation, Kepler 2.0 [2 Sep], Problems #1 and #2, Problems #3 and #4 [4 Sep].

Assignment: Problem Set #2: Due 9 Sep 2015.

Links: Centrifugal Force [xkcd's take on pseudo-forces].

3. Earth, Moon, and Sun

Earth—Moon—Sun: a hierarchical system. Orbital geometry. Phases of the Moon. The Moon's orbit. Gravity of spherical objects. Tidal forces. Response of oceans.

Slides: Earth, Moon & Sun.

Board: Iron Sphere Theorem, Tides, Response of Ocean [9 Sep], Precession & Tidal Drag, Problem #2, Problem #3 [11 Sep].

Assignment: Problem Set #3: Due 14 Sep 2015. See images of Moon below.

Links: Moon Animation, Moon at 6–Dec–2015, Moon at 20–Dec–2015, Tide, The Tides [lecture by Kelvin], Tidal Wave!, Precession of the Earth-Moon system.

4. Keeping Atmosphere

This week covered thermal equilibrium of planets, the greenhouse effect, and thermal escape of atmosphere.

Handouts: Atmospheric Properties of Planets.

Board: Keeping Atmosphere, Black-Body Radiation, Solar Luminosity & Flux, Equilibrium Temperature [14 Sep], Greenhouse Effect, Conditions for Escape, Escape of Atmosphere [16 Sep], Problem #1, Problem #2, Problem #3 [18 Sep].

Assignment: Problem Set #4: Due 21 Sep 2015.

Links: Energy flow in atmosphere (Halpern et al. 2010, Int. J. Mod. Phys. B, vol 24, 1309—1332).

5. Atmospheric Structure

This week covered hydrostatic equilibrium and temperature structure of planetary atmospheres.

Board: Structure of Atmospheres, Ideal Gas Pressure, Hydrostatic Equilibrium, Isothermal Atmospheres [21 Sep], Energy Transport, Adiabatic Lapse, Temperature Profiles: Earth and Venus [23 Sep], Problem #1, Problem #2, Problem #3 [25 Sep].

Assignment: Problem Set #5: Due 28 Sep 2015.

6. Review #1

Handouts: Review Questions #1.

Board: Rev. Question #2, Rev. Questions #3, 4, 5, Rev. Question #7 [28 Sep], Exam Question #2c, Exam Question #3a, Exam Question #4c, Problem Solving Tips [2 Oct].

7. Terrestrial Planets

This week focused on the internal structure of terrestrial planets, on their internal heat sources, and on the consequences of heat flow.

Handouts: Properties of Planets and some Major Satellites.

Slides: Terrestrial Planets 1 [5 Oct], Terrestrial Planets 2 [7 Oct].

Board: Terrestrial Planets: Structure, Seismic Evidence, Shape of the Earth, Flattening and Structure [5 Oct], Terrestrial Planets: Follow the Energy, Gravitational Energy, Radioactive Heating, Geothermal Heat Flux [7 Oct].

Assignment: Problem Set #6: Due 12 Oct 2015.

Links: Internal Structure of the Earth [Planetary Sciences, 2nd ed., de Pater & Lissauer, Fig. 6.17; note that density is given in CGS units], Absolute Radiogenic Heat Flux [Arevalo, McDonough, & Luong (2009), Earth and Planetary Science Letters, 278, p. 361, Fig. 8], Magnetization of the Sea Floor and Seafloor Spreading [Interactive animation; click on "magnet" to change polarity].

8. Giant Planets

Slides: Giant Planets [12 Oct].

Board: Giant Planets, Hydrogen: Phase Diagram, Gas Sphere Model (note corrections), Rotation & Flattening [12 Oct], Giant Planets: Energy Budget, Energy Sources, Gas Spheres: Negative Heat Capacity, Magnetic Fields: Gas Giants v.s. Ice Giants [14 Oct.], P.S. 6.1(c), 6.2(c), 6.3(c), P.S. 7.1, 7.2, 7.3 [16 Oct].

Assignment: Problem Set #7: Due 19 Oct 2015.

Links: Jupiter Submarine [another phase diagram], Jupiter Descending [clouds and more clouds].

9. Satellites & Rings

Slides: Satellites of the Giants [19 Oct], Rings [21 Oct].

Board: Roche & Hill Radii, Tidal Heating (Io), Resonance & Eccentricity [19 Oct] Non-Spherical Satellites, Orbits Around Oblate Planets, Resonances in Rings [21 Oct], P.S. 8.1, 8.2, 8.3 [23 Oct].

Assignment: Problem Set #8: Due 26 Oct 2015.

10. Asteroids & Comets

Slides: Asteroids [26 Oct], Comets and TNOs [30 Oct].

Board: Breakup Period, Giant Asteroids, Asteroid Orbits [26 Oct], Comets: "Dirty Snowballs", Tails, Outgassing Rate, Comet Lifetimes [28 Oct], P.S. 9.1, 9.2, 9.3 [30 Oct].

Assignment: Problem Set #9: Due 2 Nov 2015.

11. Review #2

Board: Rev. Question #1, Rev. Question #3 [2 Nov], Mean Free Path, Saturn's A Ring, Asteroid Belt [4 Nov], Decay Process, 4.5 Gyr from now, 4.5 Gyr ago [6 Nov].

Handouts: Review Questions #2.

12. Solar System Formation

Board: Solar System Formation, Core Collapse, Proto-Planetary Disks, Grains to Proto-Planets [9 Nov], Grains to Proto-Planets (continued), Late Stages, P.S. 10.1, 10.2 [13 Nov].

Assignment: Problem Set #10: Due 16 Nov 2015.

13. Topics: ESPs and NEOs

Slides: Other Solar Systems [16 Nov], Near Earth Objects [18 Nov].

Board: Other Solar Systems, Detection: Transit Method, Detection: Radial Velocity, Results [16 Nov], Near Earth Objects, Impact Physics, Populations & Sources, Detection & Deflection [18 Nov] P.S. 11.1, 11.2, 11.3 [20 Nov].

Assignment: Problem Set #11: Due 23 Nov 2015.

Links: Exoplanet Spectroscopy.

14. Solar Interior. I

Board: Sun: Basic Structure, Homogenious Model, Physical State, Time Scales [23 Nov].

15. Solar Interior. II

Wave-Particle Duality, Bohr's Atomic Model, Coulomb Barrier, Tunneling [30 Nov], Particles & Conservation Laws, Hydrogen Burning, Core Stability, Energy Transport [2 Dec] P.S. 12.1, 12.2, 12.3.

Assignment: Problem Set #12: Due 7 Dec 2015.

16. Review #3

Board: Physics Themes [7 Dec], Rev. Quest. 15, 20, Rev. Quest. 15, 16, Rev. Quest. 21, 22 [9 Dec].

Handouts: Review Questions #3.

Joshua E. Barnes      (barnes at
Updated: 11 December 2015
Valid HTML 4.01!