Corrections to Fall 2001 printing of Astronomy Notes:

1. Page 6, sixth line of the Time section, fourth sentence now reads:
   "If you use the classical number of 15 billion years for the age of the universe, you can squeeze the universe's entire history into one cosmic calendar year (recent measurements place the age closer to 13 billion years).
2. Page 166, first sentence of the second paragraph now reads:
   "For most of the planets, the Sun provides the energy to maintain the atmosphere temperature (and surface temperature for the terrestrial planets) and to drive the convective motions of the atmosphere."

3. Page 172, bottom paragraph of section 9.3.1, third sentence is now
   "The magenta colors are produced by nitrogen molecules at the lower end of the aurorae (up to 100 kilometers above the surface), between 100 and 200 kilometers above the surface excited oxygen atoms produce the green colors and ionized nitrogen atoms produce the blue colors, and greater than 200 kilometers above the surface oxygen atoms produce the deep red colors."

4. Page 187, third sentence of section 9.5.3 should have ``pressure'' where the second ``temperature'' is, so it will read "...has the right surface temperature and atmospheric pressure for life and liquid water to exist."

5. Page 215, last paragraph of section 10.4.5, second sentence now reads:
   "Of the approximately 1000 asteroids larger than 1 kilometer in diameter that are thought to pose a threat of impacting Earth, between 30% to 40% have been found so far."

6. Page 309, a fourth paragraph has been appended to the end of the Novae and Supernovae Type I section:
   "Since the Type I supernova form from the collapse of a stellar core of a particular mass, rather than the range of core masses possible for a Type II supernova, the Type I supernova are expected to have the same luminosity. The distances to very luminous objects can be derived using the inverse square law of light brightness if their luminosity is known. Because of their huge luminosities, the Type I supernovae could be used to measure distances to very distant galaxies. In practice there is a range of luminosities for the Type I, but the luminosity can be derived from the rate at which the supernova brightens and then fades—the more luminous ones take longer to brighten and then fade. Astronomers using Type I supernova to measure distances to very distant galaxies have come to some surprising conclusions about the history and future of the universe (see chapter 16 for more about that)."
7. Page 317, last sentence of question 13 in the Review Questions now reads:
   "If the fluctuations were slower (taking longer to brighten and then fade), would the implied size be smaller or larger?"
8. Page 342 second paragraph and page 349 second paragraph, reference to 15 billion years now changed to 13 billion years.

9. Page 381, top line, ``Fisher-Tully relation'' has been changed to ``Tully-Fisher relation'' to be consistent with other parts of the book.
10. Page 381, last paragraph of Rung 7: Hubble Law now reads:
    "Rung 4 is the critical one now for the distance scale ladder. With the fixed Hubble Space Telescope, astronomers are able to use the Cepheid period-luminosity relation out to distances ten times further than what can be done now on the ground. The ground measurements of the Hubble constant are 50 to 100 km/sec/Mpc (a factor of two in range!). With Cepheid observations at farther away distances, astronomers have constrained its value to between 64 and 80 km/sec/Mpc with a best value of 72 km/sec/Mpc. The value of 1/H_o is a rough upper limit on the age of the universe (assuming constant recession speeds!). The new Hubble constant measurement then implies an universe age of about 14 billion years. The favorite model for how the recession speeds have changed over the history the universe gives an age a little less than that of about 13 billion years with this value for the Hubble constant. This agrees with the ages derived for the oldest stars (found in globular clusters) of about 12 to 13 billion years."
11. Page 402, second sentence of the last paragraph has been changed to read:
    "Type I supernovae are very luminous and can be used as standard candles to measure very large distances because they form from the collapse of a stellar core of a particular mass (1.4 solar masses). By measuring very large distances, astronomers can determine the geometry of the universe."

For the grammar police

12. Page 380, second line at top should start with: ``is calibrated'' instead of ``are calibrated''.
13. Page 380, second sentence of section 15.3.5 should have the word ``the'' before ``inverse square law''.
14. Page 380, second line from the bottom, change ``neutral H emission'' to ``neutral hydrogen emission''.
15. Page 381, last sentence of Rung 6: Galaxy Luminosity and Inverse Square Law should begin with ``You'' instead ``We''.
16. Page 407, change the word ``decrease'' to ``decreases'' in the first sentence of the sixth paragraph that begins with "The certainty of the values...".
17. Page 415, replace "pint" with "quart" in section B.2.
18. Page 419, third sentence of section B.7.3 should begin with:
    "See chapter 5 for an explanation..."

Please let me know if you find any other parts of the textbook needing correction: nstrobel@bc.cc.ca.us

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last updated: 10 November 2001