Physics of AstronomyDr. E.J. Zita, The Evergreen State College, 5.Jan.2004Lab II Rm 2272, zita@evergreen.edu, 360-867-6853

http://academic.evergreen.edu/curricular/ PhyAstro /home.htm

TA = Emily Himmelright and (your name here?)

Outline

• Introduction to the program• Jigsaw learning and peer instruction• Survey + discussion

• Introduction to Modern Astrophysics Ch.1• Prepare 15-minute presentations• Integrating Physics + Astronomy + Math• Plan for week 1

Introduction to the Program• Physics

• Astronomy

• Math

• Seminar

• Research

• Assignments and WebX

• Covenant

http://192.211.16.13/curricular/PhyAstro/home.htm

Seminar, research, and time budgeting

Seminar: Relativity on Monday, Journal Club on Thursday (WebX)

http://192.211.16.13/curricular/PhyAstro/home.htm#seminar

Research: Planning in winter, execution in spring

http://192.211.16.13/curricular/PhyAstro/research.htm

Budgeting time:

3 x 4 = 12 hours science (MTR 1-5)

2 x 2 = 4 hours seminar (MR 5-7)

2-3 x 16 = 32-48 hours preparation (reading, HW, team meetings, research…)

Total ~ 48-60 hours/week, so be sure to schedule in R&R, to stay healthy

Covenant, Clubs, TAs, Office hours

Covenent: Please read the draft covenant online, to discuss tomorrow.

http://192.211.16.13/curricular/PhyAstro/home.htm#seminar

Clubs: Society for Physics Students: join to get Physics Today

Astronomy club: for Sky & Telescope

http://192.211.16.13/curricular/PhyAstro/research.htm

TAs = Emily Himmelright and (your name here?)

Office hours: 5-6 in the CAB (bring your dinner or snack)

(Except this week I have to leave at 5:30 to testify.)

Jigsaw learning and Peer instruction

Educational research shows that students learn best when:

• Actively engaged• Working in teams• Taking ownership of

knowledge• Expressing understanding

in own words

Here is our first exercise in peer instruction: a survey.

Survey and discussion

• Purpose: to teach your prof what we need to review, and to practice peer instruction

• Put your name on p.3• Please do pages 1 and 3-5• We will discuss it together• After discussion, do page

2, then turn it in.• After class, do page 6

(online covenant)

Intro to Modern AstrophysicsCarroll and Ostlie = CO

• Basic astronomy• Gravity + orbits• Light + spectra• Modern physics + QM• Electromagnetism• Sun and Stars• Thermal + radiation• Cosmology

Ch.1: The Celestial Sphere

1.1: The Greek Tradition; Team 1: Celestial Sphere

1.2 The Copernican Revolution; Team 2: Periods; prob.1.3

1.3 Positions on the Cel.Sph.Team 3.a: Altitude+ Azimuth (p.10-13), prob. 1.5Team 3.b: Right Ascension and Declination (p.13-15), prob.1.4Team 3.c: Precession and motion of the stars (p.15-19), prob.1.6

1.4 Physics and Astronomy

(Figures from Freedman and Kaufmann, Universe)

1.1 The Greek Tradition

The Celestial Sphere

Geocentric Ptolemaic System

Epicycles and Deferents

Angles measure the sky:

2 radians = 360 degrees = 360 °

1° = 60 arcminutes = 60’

1’ = 60 arcseconds = 60 ’’

Example: Moon subtends 1/2°

Freedman and Kaufmann #1.30: The average distance to the Moon is 384,000 km, and the Moon subtends an angle of 1/2°. Use this information to calculate the diameter of the Moon in km.

arclength D = d when is in radians

1.2 The Copernican Revolution

Geocentric model actually uses MORE epicycles and deferents, but it is conceptually simpler

Synodic period S = how long we see a planet take to return to the same place on the sky (e.g. near the same star)

Sidereal period P = how long the planet takes to orbit Sun

1 1 1

S P P

1.3.a. Positions on the Celestial Sphere

Altitude h = angle above horizon

(depends on position on Earth)

Azimuth A = angle from North

1.3.b Positions on the Celestial Sphere

Right Ascension = longitude east from vernal equinox

Vernal equinox = place and time of Sun’s crossing the celestial equator, going north

Declination = latitude north of celestial equator

1.4 Physics and Astronomy

Physics: What fundamental, quantitative principles explain the structure and evolution of the natural world?

Astronomy: What do we see in the sky, and how do things move and change?

Astrophysics: How can Physics explain what Astronomy observes?

Four realms of physics

Classical Mechanics(big and slow:

everyday experience)

Quantum Mechanics(small: particles, waves)

Special relativity(fast: light, fast particles)

Quantum field theory(small and fast: quarks)

Four fundamental forces

Physics, Astronomy, and Math for week 1:

Astronomy (Freedman & Kaufmann)

Ch.1: Astronomy and the Universe

Team 1: Ch.1.1 – 1.5 (intro + angles)

Team 2: Ch.1.6 – 1.8 ( scientific notation and distances)

Ch.2: Knowing the Heavens

Team 3: 2.1-2.3 (constellations and diurnal motion)

Team 4: 2.4-2.5 (celestial sphere and seasonal changes)

Team 5: 2.6-2.7 (precession and time)

Mathematical Methods in the Physical Sciences (Boas)

Spherical geometry, Ch.5, Section 4

Candidate HW questions for week 1:

Astrophysics (Carroll and Ostlie)

Ch.1: Problems 1, 3, 4, 5, 6

Astronomy (Freedman & Kaufmann)

Ch.1: Review: 5, 11, 12, 15; Advanced: 18, 20, 22, 26, 27, 28, 30, 33

Observing: 42, 43 (Teams 1, 2)

Ch.2: Review: 6- 8, 10- 14, 16, 17, 20, 22;

Advanced: 23, 29, 32, 34, 37, 38

Observing: 54, 56, 57 (Teams 3, 4, 5)

Mathematical Methods in the Physical Sciences (Boas)

Ch.5, Section 4, Problems 1 (a, d), 2(a), 4(a, b), 24, 25