Announcements Astro 2 Supplies Mastering Astronomy online but look at the PowerPoint slide show at Meanwhile… –Lecture notes (and everything else) are available online at Fall Semester

Announcements Remember to attend third hour! –Which Third Hour you are assigned will be posted online and on our class bulletin board (just outside class)online –IMPORTANT NOTE: 3 RD HOUR DOES NOT FULFILL A LAB REQUIREMENT: IT IS SIMPLY THE 3 RD HOUR OF THE LECTURE Astro labs: Astro 11 and Astro 14 –Bring the 3 rd hour sheets (found in the Astro 2 Handbook)! Homework – Assignment 01 is due on next Friday by Noon! –Homework assignments from MasteringAstronomy at –Do Assignment 00 to get used to the style of online homework Remember your 4-digit Astro 2 ID number –That was the number printed on the green cards –Put this on 3 rd hour assignments and any else you turn in Fall Semester

Use of the CPS keypads Coming up next week

© Sierra College Astronomy Department4 Overview “Secrets” to Success (For a grade of B or A) –Do the assigned reading (fast) before the first lecture of the week. –Read all the homework questions before the first lecture of the week. –Attend lectures with PowerPoint lecture notes from the Student Handbook. –Work in groups. –Do not wait to the last minute to prepare for exams. –Do some extra credit. –Ask questions.

Grade Breakdown Total 500 points A = 90% or more of total points assigned (= 450) B = 80% or more, but less than 90%, of total points assigned (= 400) C = 70% or more, but less than 80%, of total points assigned (= 350) D = 60% or more, but less than 70%, of total points assigned (= 300)

Objectives (See Handbook) General Celestial Concepts/Astron. History Basic Principles of Physics –Nature of Light, Atoms, Spectra, and Telescopes Earth, Moon, Inner and Outer Planets Pluto, Comets, Asteroids and other debris The Sun Planetary Systems Formation

Why do we use special units in astronomy? See, I told you this ball is exactly miles away from the hole! Altered Slide

Lecture 1: Overview, Dimensions, and the Scientific Method Dimensions and the Language of Math Units determined by the scale of the object(s) under study (e.g., nm, AU, ly, and Mpc) Fundamental constants and particles symbolically represented (e.g., c, G, e -, and  ) inEven with large assortment of units, the vast extremes in time and space scales require exponents Astro 2 minimum math: “simple” algebra –Kepler’s Third Law, Newton’s Second Law, Universal Gravitation

Numbers in Astronomy We express very big or very small numbers in terms of scientific notation –In Appendix C1 and C2 –Large and small numbers: –Distance from Earth to Sun: 149,600,000,000 m –Mass of hydrogen atom: kg NEXT

Powers of Ten Numbers greater than one Numbers less than one 10 = = = 10×10 = = = 10×10×10 = = ,000,000 = = ,000,000,000 = = Move the decimal to the leftMove the decimal to the right NEXT

Scientific Notation We often express large or small numbers in terms of a number between 1 and 10 multiplied by a power of ten –In Appendix C1 and C2 149,600,000,000 m = × m kg = 1.67 × kg

Units Not in Appendix Most quantities have units –Most common exception: ratios We will be using the MKS system (meter-kilogram-second) Other units are hybrids of these e.g. : –Newton (N): kg · m/s 2 (Force) –Joule (J): N · m (Energy) –Watt (W): J/s (Power) For any problem you solve, treat units separately and cancel/combine appropriately NEXT

Prefixes symbolprefixmeaning nnano-One billionth =  micro-One millionth = mmilli-One thousandth = ccenti-One hundredth = kkilo-One thousand = 10 3 MMega-One million = 10 6 GGiga-One billion = 10 9 NEXT

© Sierra College Astronomy Department14 Lecture 1: Overview, Dimensions, and the Scientific Method What is science? Name some important elements in the scientific method: NEXT

Lecture 1: Overview, Dimensions, and the Scientific Method What is science? “ The true scientific method is to test hypotheses. A good hypothesis must predict some things about nature, and if the predictions are wrong, the hypothesis must be rejected or modified. Though a hypothesis can never be proven ultimately true, if experiments keep turning up consistent results, it is considered more and more reliable and comes to be an accepted theory or law.” Hartmann (from another astronomy text) NEXT

Lecture 1: Overview, Dimensions, and the Scientific Method What is science? Error analysis –How well do you know what you know? Contradictory results –Which result do you ignore? Framing questions –Creativity Aesthetics –How do you define simplicity, beauty? NEXT

© Sierra College Astronomy Department17 Lecture 1b: Overview, Dimensions, and the Scientific Method Astronomy and the Scientific Method How far is it? What are its physical characteristics? How fast does it move and why? What allows it to be detected? How are any of the above features related? What process created it?