ASTR 1101-001
Spring 2008
Joel E. Tohline, Alumni Professor
247 Nicholson Hall
WELCOME TO ASTRONOMY
The required
textbook for this
course is
Universe
Eighth Edition
by Roger A. Freedman and
William J. Kaufmann III
(©2007, W.H. Freeman & Company)
UNIVERSE EBOOK
An ALTERNATE version of the textbook is available at a
lower cost in eBook form!
It includes…
• The complete textbook – every word, graphic,
table, and problem.
• The ability to take notes, highlight, and print.
• Resources such as animations, simulations, and
practice tests.
• Convenient access to your textbook from any
Internet connection – no more carrying around those
heavy books!
www.ebooks.bfwpub.com/universe8e
UNIVERSE EBOOK
If your textbook was
packaged with an eBook
access code, you can
redeem it at the site:
1. Click “register.”
2. Fill out the information
and you’re ready to go.
* Be sure to hold on to the access
card until you redeem it.
www.ebooks.bfwpub.com/universe8e
UNIVERSE EBOOK
If you would like to
purchase the access,
you can do so at the site:
1. Click “purchase.”
2. Enter your school Zip code
3. Choose a user name and
password. Fill out the
remaining info and you’re
ready to go.
* Be sure to remember your
username and password
www.ebooks.bfwpub.com/universe8e
Light-Travel Times
Speed of light, c = 3 x 108 meters/second
• Travel around the Earth
– Circumference of the Earth = pD = 3.14 x (1.28 x 107
m)† = 4.02 x 107 meters
– Time of travel = distance/speed = (4.02 x 107 m)/(3 x
108 m/s) = 0.134 seconds
• Travel from Earth to Moon
– Earth-Moon distance = 3.84 x 108 meters‡
– Time of travel = distance/speed = (3.84 x 108 m)/(3 x
108 m/s) = 1.3 seconds
†Textbook
Appendix 2
‡Textbook Appendix 3
Light-Travel Times
•
•
•
•
•
Sun-to-Earth = 8 minutes
Across the Radius of the Sun = 2 seconds
Earth-to-Saturn = 80 minutes
Sun-to-Neptune (edge of solar system) = 4 hrs
Sun-to-Proxima Centauri (nearest neighbor star) = 4.4
years
• Across the diameter of our Milky Way Galaxy =
100,000 years
• From the Andromeda Galaxy (nearest major neighbor
galaxy) to us = 2.5 million years!