The Overview Effect Images captured by the EPIC camera on NASA s DISCOVR satellite Credit NASA NOAA Course Announcements Astronomy Labs Start Next week Register for Mastering Astronomy as soon as possible Course ID LINDSAYA151F16 Buy 3 x 5 Notecards for Notecard Questions Assignments Reading Assignments Chapter 1 Sections 1 1 1 3 1 4 Read by Monday 22 Aug Parallel Lectures CC Astronomy Episodes 1 2 Watch by Monday 22 Aug Mastering Astronomy Introduction to Mastering Astronomy Due Thursday 25 Aug at 11 59 PM EDT Pale Blue Dot Carl Sagan Video Lin k You Are Here CHAPTER 1 Charting the Heavens Credit Dan Cindy Duriscoe FDSC Lowell Obs USNO What is Astronomy It s a science Astronomy is the study of the Universe Universe the total of space time matter and energy Study of celestial objects seen and unseen and the physics that governs them Is not Astrology We don t pseudoscience here Concerned with big picture questions Where did everything come from Where is everything going How did the Universe Solar System Earth life form Concerned with everything from the largest structures Cosmic Microwave Background and the Cosmic Web to the smallest structures Modern Atomic Physics in the Universe What is Astronomy It s a science Astronomy is the study of the Universe More precisely the study of celestial objects and the physics that governs them Universe the total of space time matter and energy Our laboratory is the universe Our instruments are telescopes ESO s VLT Observatory What is Astronomy The entire Universe That s a lot of ground space to cover More precisely still it is the study of the planets moons comets asteroids stars exoplanetary systems what lies between the stars the interstellar medium nebulae galaxies luminous matter dark matter dark energy the structure of the universe the origins and fate of the universe etc No single person or type of astronomer can study all of these topics In order to do so a plethora of scientific engineering and humanity fields are required E g Physics mathematics chemistry geology biology engineering psychology philosophy education the arts of all kinds to communicate and inspire In order to effectively talk about this in a universal way we need to have a few standards Scientific Notation Or how to easily write large and small numbers Scientific Notation See Appendix 1 A concise way to express large and small numbers Decimal Notation x Power of Ten Examples a 100 1 0 x 102 b 10 000 000 000 000 000 000 000 1 0 x 1022 c 149 600 000 1 496 x 108 d 0 01 1 0 x 10 2 e 0 00000000067 6 7 x 10 10 10 2 1 102 1 100 The Metric System Need of a Standard System The metric system is a standardized system of measure based on the powers of ten 0 001 0 01 0 1 1 10 10 3 10 2 10 1 100 101 100 1000 102 103 Syst me Internationale SI d unit s Our agreed standard metric system SI is a combination of a prefix indicating what power of ten and a base unit of measure Prefixes next slide length meters m time seconds s force Newtons N energy Joules pressure Pascals frequency Hertz etc The Metric System Prefix Unit of Measure Important Prefixes for this class Prefix symbol Large giga G 109 Billion mega M 106 Million kilo k 103 Thousand Small centi c 1 100 0 01 Hundredth milli m 10 3 Thousandth micro 10 6 Millionth nano n 10 9 Billionth Astronomical Sizes Sometimes things are so large they need a new unit The light year ly or the distance light can travel in the time of one year Speed of light c 3 0 x 105 km s 1 year 365 25 days x 24 hr x 60 min x 60 s 3 156 x 10 7 seconds So 1 ly 3 0 x 105 km s x 3 156 x 107 s 9 46 x 1012 km or 9 460 000 000 000 km 9 46 trillion kilometers The Astronomical Unit AU is the average distance between the Earth and the Sun 1 AU 1 496 x 108 km 1 5 x 108 km is close enough Ex Jupiter is 5 2 AU from the Sun instead of 7 8 x 108 km Astronomical Time The age of things Age of the Universe 13 798 0 037 billion years ref As determined by NASA s Planck Mission 13 798 Gyr Age of the Solar System 4 5682 billion years ref As determined by Lead Lead Pb Pb dating of meteorites 4 5682 Gyr Age of Modern Humans Homo Homo Sapiens Approximately 200 000 years 0 001 age of Universe 0 004 age of SS Carl Sagan s Cosmic Calendar The age of things in perspective Imagine scaling the entire history of the Universe 13 8 Gya to fit on a calendar January 1st the instant past midnight is the Big Bang or start of the Universe in time as we understand it The present moment is at December 31st at the instant before midnight Month 1 14 Gya Day 37 5 Myr Hour 1 6 Myr Min 26 000 years Sec 435 years Carl Sagan s Cosmic Calendar Cosmic Calendar s December 15 December First Animals 25 December Dinosaurs 30 December Dinosaurs go extinct 31 December after 11 54 PM Age of Modern Humans Carl Sagan s Cosmic Calendar Cosmic Calendar s Final Minute Our Place in Space Our cosmic address Earth Solar System Milky Way Galaxy The Local Group Laniakea Supercluster the Universe Local Supercluster 100 000 000 ly Milky Way UNIVERSE 1 000 000 000 000 000 000 km Local Group 10 000 000 ly Or 100 000 light years Earth 12 800 km Solar System 10 000 000 000 Our Place in Space UNIVERSE Our cosmic address Earth Solar System Milky Way Galaxy The Local Group Laniakea Supercluster the Universe Local Supercluster 108 ly or 100 Mly Milky Way 1018 km Or 105 light years Local Group 107 ly or 10 Mly Earth 12 800 km Solar System 1010 km Our Place in Space A bit more precisely These are all structures we will study in this course You should have and idea of which is bigger than which The Scale of the Universe A reason why we needed all those prefixes and units The Scale of the Universe 2 Cary and Michael Huang Each time the exponent goes up or down by one we say we have increased or decreased by an order of magnitude Current size m scale in Scientific Notation Understanding the Night Sky Intro slide How to find North via the North Star Polaris also known as the North Star Understanding the Night Sky Basic Concepts From our perspective the stars appear to on the inside of a giant celestial dome over our heads Add in the half of the sky we can t see and dome becomes the Celestial Sphere Stars are very far away and therefore appear to have fixed relative positions in the sky Concept of Fixed Background or rather …
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