Welcome to Astronomy!

Transcription

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2 Welcome to Astronomy! Dr. Tony Travouillon Office hours BYKH-115 Mondays from 5:30 to 6:30pm Skype appointments also available and even preferred CLASS WEBSITE: There you will find: The lectures, the homework, and class details.

3 Resources Foundations in Astronomy By Seeds & Backman Optional but well recommended Available at the library Other introductory textbooks Alternative resource: Others: Bad astronomy: Astronomy picture of the day: Available on Netflix: Edge of the Universe, Cosmos

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5 Grading Category Each Total Homework 10% Essay 15% Debate 15% Class Participation 10% 3 Midterms 10% 30% Final Exam 20%

6 Essay Due date: October 18 th Length: >2,000 words (4~5 pages single space) Topic: The Hubble space telescope and its contribution to our knowledge of the Universe

7 Debate Topic: How common is intelligent life in our galaxy? Details and guideline available later this term. Start thinking what time you want to be on.

8 Extra credit opportunity For up to 5% extra credit student can either Visit an astronomy event. Document it with a 1 page report and a photo of yourself at the event. Example: Mt Wilson Observatory, The Griffith Observatory, The Santa Clarita Local Group. Keep a picture diary of the moon phases through out the term. With semi-daily observations and analysis (1 page plus photos)

9 15 pages of B/W pages are FREE everyday in the ASG Computer Lab. Anywhere else on campus, they must purchase a print card and pay for prints in the Library, TLC, and Canyons Hall, etc. We offer students limited daily amounts of FREE printing (B/W & Color) and photocopying. In addition, free faxing, scanning and use of an electronic piano! - all part of their Student Support Fee Benefit. Equipment/Software: There are 36 Dell PC's with Office 2013, Minitab, SPSS, Photoshop & Illustrator. 3 imac Computers with Office for Mac 2011, iworks Suite & Adobe Creative Suite. The Computer Lab is located in the Student Center near the Cafeteria ASG Computer Lab Web Page: **click here** ASG Computer Lab - FALL hours : Valencia Campus Monday, Tuesday & Thursdays: 8:00 am 5:00 pm Wednesdays: 8:00 am - 7:00 pm Fridays: 8:00 am Noon (benefits at CCC - Room 204)

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

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

12 What is the measurement system used in astronomy? metric system Each factor of ten difference results in a single move of the decimal. Prefix Power of Ten Word Mega 10 6 Million Kilo 10 3 Thousand Micro 10 6 One Millionth Nano 10 9 One Billionth Angstrom 10 10

13 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)

14 How are astronomical distances measured? Distances between objects in space are huge! The astronomical unit (AU) is the average Earth-Sun distance. 1 AU 1.96 x 10 8 km x 10 7 miles

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16 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

17 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

18 The parsec (pc) is the distance at which 1 AU subtends 1 arcsecond. 1 pc 3.26 LY 206,265 AU 1º = 3600

19 Practice What is the correct order from smallest to largest? 1 mile 1 pc 1 meter 1 LY 1 nm Earth s Diameter 1 AU

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21 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

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

23 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?

24 History of astronomy 1

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26 Stonehenge is an ancient time keeper and astronomical calculator

27 Diagram of Stonehenge at summer solstice View toward the Heelstone

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30 Brainstorm! Can you think of another 3D object that sometimes casts a circular shadow?

31 Eratosthenes (200BC) Measured the earth circumference using the shadow of the sun and a well. Let s do the math! If the distance between Alexandria and Syene is 800km, what is the circumference of the earth?

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34 Brainstorm! Why were the Greeks the first in Astronomy at this time?

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36 Brainstorm! How many objects can you identify on this map?

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38 Issues of Ancient Astronomy (II) The retrograde (westward) motion of the planets- The solution : epicycles!

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40 Epicycles Introduced by Ptolemy (circa A.D. 140) The ptolemaic system was considered the standard model of the Universe until the Copernican Revolution.

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44 Other civilizations contributions to Astronomy 1. Babylonian Astronomy: One of the earliest civilization to make written records including observations of the sky. They recorded the temporal evolution of the positions of celestial objects in the sky. First almanacs based on the movement of the sun and the moon. Also likely made the first observations of Halley s comet.

45 Other civilizations contributions to Astronomy 2. Egyptian Astronomy: Also charted the sky. The Pyramids of Giza are aligned with the north star. Developed a calendar based on the sun and stars very similar to our own and used to predict the periods of the flooding for the Nile.

46 Other civilizations contributions to Astronomy 3. Indian Astronomy Surviving work by astronomer Aryabhatiya (~400AD) shows early knowledge of the Earth motion on its axis including very accurate calculation of the sidereal day and year, Solar and Lunar eclipses and the circumference of the Earth,

47 Other civilizations contributions to Astronomy 4. Chinese Astronomy Extensive record start in the 4 th century BC with one of the oldest star catalogues and the most complete work on the planet Jupiter available of the time. First recording of a supernova in 185 AD

48 Other civilizations contributions to Astronomy 5. Meso-American Astronomy Developed calendars and almanacs used to organize their agriculture, events and even wars. Venus was of particular importance for the Mayan civilization while the Incans favored the Pleiades star cluster for their predictions. Also had accurate knowledge of the sun (which they worshipped) and its solstices.

49 Other civilizations contributions to Astronomy 6. Islamic Astronomy Improvements made to the Ptolemaic model and observations of new celestial objects such as the large Magellanic cloud and the Andromeda Galaxy. Construction of the most accurate sextant available at the time.

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