Astro 1 - Lecture 4


Matthew A. Bershady

Department of Astronomy & Astrophysics

Penn State University


Fall 1996

This document may not be copied for sale

All Rights Reserved

© 1995 Matthew A. Bershady

Lectures Lecture page Astro1 page


FROM HERESY TO GRAVITY


1. The advance of knowledge


Essential ingredients:

* Ability and willingness to question

* New observations

methodology (methods of inquiry)

technology

* Analytical tools

mathematics (analytic solutions)

computers (numerical solutions)

Ancient and modern debates:

Ptolmeic vs. Copernican systems

(Earth centered)


(Sun centered)


... compare to:


Steady State vs. Big Bang

(universe always existed)

(creation event)



Chronology of Conceptual Developments in Cosmology

. . 400 BC . 900 AD . .
. . . . . . .
Aristotle 384-322 . . . . .
. . 300 BC . 1000 AD . .
Aristarchus 310-230 . . . . .
Eratosthenes 276-194 . . . . .
. . 200 BC . 1100 AD . .
Hipparchus 146-127 . . . . .
. . . . . . .
. . 100 BC . 1200 AD . .
. . . . . . .
. . . . . . .
. . 0 . 1300 AD . .
. . . . . . .
. . . . . . .
. . 100 AD . 1400 AD . .
Ptolemy 140 . . . . .
. . . . . Copernicus 1473-1543
. . 200 AD . 1500 AD . .
. . . . . . .
. . . . . Tycho Brahe 1546-1601
. . 300 AD . 1600 AD . .
. . . . . Galileo Galilei 1564-1642
. . . . . Johannes Kepler 1571-1630
. . 400 AD . 1700 AD . .
. . . . . Isaac Newton 1642-1727
. . . . . . .
. . 500 AD . 1800 AD . .
. . . . . . .
. . . . . . .
. . 600 AD . 1900 AD . .
. . . . . Albert Einstein 1879-1955
. . . . . Edwin Hubble 1889-1953
. . 700 AD . 2000 AD . .
. . . . . . .
. . . . . . .
. . 800 AD . . . .
. . . . . . .
. . . . . . .


Q4.1 If the parallax of a star is observed to be 1/3 arcsecond, what is its distance from the Earth?

(a) 1/3 parsec

(b) 3 parsecs

(c) 3 * 3.26 parsecs

(d) 1/3 a light year

(e) 3 light years

Q4.2 Ignoring precession, the orientation of the Earth's spin axis is fixed with respect to all but which one of the following?

(a) the constellations

(b) the moon's orbital plane

(c) the celestial sphere

(d) the planets' apparent positions on the sky

(e) the plane of the ecliptic


Lectures Lecture page Astro1 page
This page and its links look best with Netscape 2.0 image options set to "dither."
Last updated: Aug 28, 1996 Matthew A. Bershady