Physics 172
Spring 2025

Stellar Astronomy & Cosmology 

Course Materials:

• Week 0: 1/22-24                  Intro to Astronomy [Ch. 1, 2]
  Physics 172 syllabus
  Wednesday, January 22: Class cancelled due to winter weather.
  Friday, January 24: Lecture 1: Course structure, science & astronomy, units & notation.
  Friday, January 24: Lecture Notes: SI units, speed of light, light year.
  
  Problem Set #1, due Friday, January 31, 2025 (hard copy, due in-class)
  
  
  
• Week 1: 1/27-31                  Basic Physics I: Motion and Orbits [Ch. 2, 3]
  Monday, January 27: Lecture 2: Distances with c, scientific notation, length scales, Erastostenes.
  Monday, January 27: Lecture Notes: Light years, exponents, and trigonometry review.
  
  Wednesday, January 29: Lecture 3: Orbital basics, seasons, parallax, Kepler's laws.
  
  Friday, January 31: Lecture 4: Constellations, Kepler's laws.
  Friday, January 31: Lecture Notes: Kepler's 2nd law at aphelion and perihelion.
  
  Problem Set #2 is due Friday, February 7 by 9:00 AM on ExpertTA.
  
  
  
• Week 2: 2/3-7                  Basic Physics II: Newton and Gravity [Ch. 3]
  Monday, February 3: Lecture 5: Galileo, gravity, Galilean relativity, and Newton's laws.
  Monday, February 3: Lecture Notes, Problem #1: Kepler's 2nd law at aphelion and perihelion (continued).
  Monday, February 3: Lecture Notes, Problem #2: Orbital speed vs orbital radius.
  
  Wednesday, February 5: Lecture 6: Galilean relativity, Newton's laws, momentum and energy, gravity by Newton.
  Wednesday, February 5: Lecture Notes: Conservation of momentum, rifle recoil.
  
  Friday, February 7: Lecture 7: Newton's laws, circular motion, center of mass, angular momentum.
  Friday, February 7: Lecture Notes: Acceleration due to Earth's gravity.
  
  Problem Set #3 is due Friday, February 14 by 9:00 AM on ExpertTA.
  Extra practice problems for week 2 topics (ungraded)
  
  
  
• Week 3: 2/10-14                  Basic Physics III: Light and Matter [Ch. 5, 16.1-2]
  Monday, February 10: Lecture 8: Escape velocity, tidal forces, electromagnetic waves.
  Monday, February 10: Lecture Notes: Newton's version of Kepler's 3rd law for mass determination.
  
  Wednesday, February 12: Lecture 9: Electromagnetic spectrum, blackbody radiation, light pressure.
  Wednesday, February 12: Lecture Notes: Blackbody radiation of a hot star.
  
  Friday, February 14: Lecture 10: Photons, atomic structure, spectroscopy, Doppler effect, nuclear particles.
  
  Problem Set #4 is due Wednesday, February 19 by 9:00 AM on ExpertTA.
  Extra practice problems for week 3 topics (ungraded)
  
  
  
• Week 4: 2/17-21                  Nuclear Physics & Astronomy Instruments [Ch. 5, 16.1-2, 6]
  Monday, February 17: Lecture 11: Doppler effect, Nuclear particles, P-P chain solar fusion, charged (anti-)particles.
  Monday, February 17: Lecture Notes: Doppler shift.
  
  Wednesday, February 19: class cancelled due to winter weather.
  
  Friday, February 21: class cancelled due to winter weather.
  
  MIDTERM #1 (originally on Friday, Feb. 21) is scheduled for Monday, February 24, 2025 (in-class)
  Formula sheet for midterm #1