1. Introduction to Astronomy & Tools of Science (Chapter 1)

2. Student Learning Objectives Diagram your location in space Write and interpret numbers in scientific notation Define astronomical distance measurements Apply the scientific method.

3. What is our location in space?  We live on planet Earth  In the Milky Way Galaxy (10 12 stars)  Part of the Local Group (Galaxy Cluster)  Within in the Virgo Supercluster  One tiny spot in the visible Universe

6. Practice Diagram your location in space.

7. What is Scientific Notation? Multiples of 10  The number of multiples/divisions of 10 is indicated as a power. Blue Light Blue Light = 450 x 10 -9 meters Earth-Sun Earth-Sun d = 93 x 10 6 miles

8. Practice 1)Write 67,000 in scientific notation - Distance from center of galaxy to Sun 2) Write 10 12 in standard notation - Number of stars in our galaxy 3) Write 3.5 x 10 −14 in standard notation - A frequency of red light

9. What is the measurement system used in astronomy? metric system  Each factor of ten difference results in a single move of the decimal. PrefixPower of TenWord Mega10 6 Million Kilo10 3 Thousand Micro10 -6 One Millionth Nano10 -9 One Billionth Angstrom10 -10

10. Practice 1) Red light has an average wavelength of 650 nm. Is this a very small or very large number? 2) Distances to galaxies are measured in Mega-parsecs. This is (hundreds, thousands, millions) of parsecs. (choose one)

11. How are astronomical distances measured? Distances between objects in space are huge!  The astronomical unit (AU) is the average Earth- Sun distance. 1 AU1.96 x 10 8 km9.298 x 10 7 miles

13. Light Year  A light year measures distance, not time.  The light-year (LY) is the distance light travels through a vacuum in 1 year. Light travels 1 AU in about 8 Minutes

14. Earth - Moon: 1.3 Light Seconds Earth - Sun: 8 Light Minutes Earth - Mars: 13 Light Minutes Earth to Proxima Centauri (nearest star) 4.3 Light Years Earth to the other side of our own galaxy 52,000 Light Years

15.  The parsec (pc) is the distance at which 1 AU subtends 1 arcsecond. 1 pc3.26 LY206,265 AU 1º = 3600´´

16. Practice What is the correct order from smallest to largest? 1 mile1 pc1 meter 1 LY 1 nm Earth’s Diameter1 AU

17. What is science?  Science is not simply a collection of facts, but rather an objective process of quantifying what we observe.  The outcomes of science are laws and theories with repeatable results.  Tested  Verified

18. How is science done? Measurements Observations  Each scientist must be able to obtain the same results. Example: Example: Atomic Spectra Observe/Question  Hypothesize/Predict  Observe/Confirm  Theory 

19. Questions to Consider 1) The scientific method is a circular process. Explain 2) What do you think happens if scientists cannot obtain the same results? 3) Can the scientific method be used to answer all questions? 4) What is pseudoscience?

20. What is astronomy?  Astronomy is a science.  Astronomers study the universe and all objects contained within the universe.