1. LECTURE 2, AUGUST 26, 2010 ASTR 101, SECTION 3 INSTRUCTOR, JACK BRANDT jcbrandt@unm.edu 1ASTR 101-3, FALL 2010

2. MASTERING ASTRONOMY AN INTRODUCTION BY CELESTE NOSSITER EXECUTIVE SALES REPRESENTIVE PEARSON HIGHER EDUCATION ARTS AND SCIENCES ASTR 101-3, FALL 20102

3. 3 THE SCIENTIFIC METHOD FACTS OR OBSERVATIONS

4. ASTR 101-3, FALL 20104 THE SCIENTIFIC METHOD FACTS OR OBSERVATIONS ORGANIZING IDEAS OR THEORY

5. ASTR 101-3, FALL 20105 THE SCIENTIFIC METHOD FACTS OR OBSERVATIONS ORGANIZING IDEAS OR THEORY PREDICTIONS AND TESTING

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8. POWERS OF TEN-1 10 3 = 1,000 10 2 = 100 10 1 = 10 10 0 =1 10 -1 = 0.1 10 -2 = 0.01 10 -3 = 0.001

9. ASTR 101-3, FALL 2010 POWERS OF TEN-2 Some examples: Distance to the Sun is: 15,000,000,000,000 cm = 1.5 x 10 13 cm Radius of the helium atom is: 0.00000001 cm = 1 x 10 -8 cm

10. ASTR 101-3, FALL 2010 POWERS OF TEN-3 A sample calculation. Add exponents to multiply & subtract exponents to divide. Population of the U.S. (2004) was 293,850,000 or 2.94 x 10 8 The National Debt (2004) was $7,443,900,000,000 or $7.44 x 10 12 Ratio is 7.44/2.94 x 10 12-8 = $2.5 x 10 4

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13. Stars in a constellation are Question 6 a) physically close to each other. b) usually equal in brightness. c) about the same age. d) about the same distance away. e) in the same part of the sky.

14. Question 6 a) physically close to each other. b) usually equal in brightness. c) about the same age. d) about the same distance away. e) in the same part of the sky. Stars in a constellation are Stars within a constellation might be very different distances, ages, types, and brightnesses.

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21. Question 3 What is the path that the Sun, Moon, and planets follow through the constellations? a) the celestial equator b) the north celestial pole c) the Milky Way d) the zodiac e) the ecliptic

22. a) the celestial equator b) the north celestial pole c) the Milky Way d) the zodiac e) the ecliptic Question 3 What is the path that the Sun, Moon, and planets follow through the constellations? The ecliptic also marks the plane of Earth’s orbit around the Sun.

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25. ASTR 101-3, FALL 2010 CALENDARS-1 Roman Civil Calendar = “a mess” Julian Calendar (Leap Years) = 365.2500 days Tropical Year = 365.2422 days Difference = 0.0078 days Gregorian Calendar = 365.2425 days, Leap Years adjusted for “Centurial Years”

26. ASTR 101-3, 2010 CALENDARS-2 Gregorian Calendar adopted in 1582 AD, but not accepted outside Catholic Countries Adopted by Great Britain in 1752 AD George Washington was born on February 11 (Julian), but February 22, 1732 AD (Gregorian) Now the universal Civil Calendar

27. ASTR 101-3, FALL 2010 TIME ZONES, ETC Time zones adopted in the 1880s prompted by the needs of the railroads International Date line in the Pacific Ocean Leap Second, added from time to time because the earth’s rotation is not constant