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Course Course Website: http://blogs.umass.edu/astron101-tburbine/http://blogs.umass.edu/astron101-tburbine/ Textbook: Pathways to Astronomy (2nd Edition) by Stephen Schneider and Thomas Arny. You also will need a calculator. Slide 2 Office Hours Mine Tuesday, Thursday - 1:15-2:15pm Lederle Graduate Research Tower C 632 Neil Tuesday, Thursday - 11 am-noon Lederle Graduate Research Tower B 619-O Slide 3 Homework We will use Spark https://spark.oit.umass.edu/webct/logonDisplay.d owebcthttps://spark.oit.umass.edu/webct/logonDisplay.d owebct Homework will be due approximately twice a week Slide 4 Homework #1 (Due today) Find an article concerning a topic concerning the Solar System and write about why you found it interesting. Include the name of the article and where it was published. Submit using Spark Slide 5 Homework #2 (due Tuesday) 10 questions In Assessment on Spark Slide 6 Why should we learn about the Solar System? http://www.thisistheend.com/2009/08/the-ihc-on- the-tv.phphttp://www.thisistheend.com/2009/08/the-ihc-on- the-tv.php Slide 7 Metric System 1 kilometer = 1,000 meters 1 meter = 100 centimeters 1 centimeter = 10 millimeters Slide 8 Distances An Astronomical Unit (AU) is the average distance between the Sun and Earth 1 AU = 150 x 10 6 km = 150 x 10 9 m 1 light-year is the distance light travels in a year 1 light-year = 9.5 10 15 meters Slide 9 Scientific Notation 10000 = 10 4 100000000 = 10 8 10000000000 = 10 10 100000000000000000000 = 10 20 0.001 = 10 -3 0.0000001 = 10 -7 Slide 10 How do you write numbers? 31,700,000 = 3.17 x 10 7 2,770,000 = 2.77 x 10 6 0.00056 = 5.6 x 10 -4 0.0000078 = 7.8 x 10 -6 Slide 11 How do you do multiply? 10 6 x 10 8 = 10 (6+8) = 10 14 10 -5 x 10 3 = 10 (-5+3) = 10 -2 (3 x 10 4 ) x (4 x 10 5 ) = 12 x 10 (4+5) = 12 x 10 9 = 1.2 x 10 10 Slide 12 How do you divide? 10 8 /10 6 = 10 (8-6) = 10 2 10 -6 /10 -4 = 10 (-6-(-4)) = 10 -2 (3 x 10 8 )/(4 x 10 3 ) = x 10 (8-3) = 0.75 x 10 5 = 7.5 x 10 4 Slide 13 What is a galaxy? Slide 14 Is a massive, gravitationally bound system consisting of stars, gas and dust, and dark matter. Galaxies can contain between ten million and a trillion stars Dark matter is matter that does not emit or reflect enough radiation to be seen, but whose gravitation effects can be felt http://en.wikipedia.org/wiki/Image:NGC_4414_%28NASA-med%29.jpg Slide 15 When we are looking at stars or galaxies We are looking into the past Light-year is the distance light travels in a year. Slide 16 Milky Way Galaxy Milky Way is 100,000 light-years in diameter There are ~200 billion stars in the Milky Way (estimates from 100-400 billions stars) http://www.venusproject.com/ecs/images/photos/galaxy.jpg Slide 17 What is the Universe? Slide 18 Sum total of all matter and energy all galaxies and everything between them Observable universe portion of the universe that can be seen from Earth, probably only tiny portion of the whole universe ~93 billion light-years wide Slide 19 How many stars in the Universe Say there are 100 billion galaxies Each galaxy has 100 billion stars So how many stars in the universe Slide 20 Answer Number of stars in universe = (100 x 10 9 ) x (100 x 10 9 ) = 10000 x 10 18 = 1 x 10 22 = 10,000,000,000,000,000,000,000 This is about the same number of grains of sand in every beach in the world Slide 21 Questions: How many of these 10 22 stars have planets? How many of these planets have life? Slide 22 My Very Eager Mother Just Served Us Nine Pizzas Slide 23 My - Mercury Very - Venus Eager - Earth Mother - Mars Just - Jupiter Served - Saturn Us -Uranus Nine -Neptune Pizzas - Pluto Slide 24 Does anyone play basketball? Slide 25 Assume That the sun is the same size as a basketball Basketball diameter = 24.4 cm Suns Diameter = 1.4 x 10 9 m = 1.4 x 10 11 cm Scale Factor = 1.74 x 10 -10 Multiply scale factor by actual diameters of planets to get their approximate size Slide 26 Mercury Diameter = 4.88 x 10 6 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 8.5 x 10 -4 m = 0.85 mm Slide 27 Mariner 10 Messenger Slide 28 Venus Diameter = 1.21 x 10 7 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 2.1 x 10 -3 m = 2.1 mm Slide 29 Mariner 10 Slide 30 Earth Diameter = 1.28 x 10 7 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 2.2 x 10 -3 m = 2.2 mm Slide 31 Apollo 17 Slide 32 Mars Diameter = 6.80 x 10 6 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 1.2 x 10 -3 m = 1.2 mm Slide 33 Hubble Space Telescope Slide 34 Jupiter Diameter = 1.43 x 10 8 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 2.5 x 10 -2 m = 25 mm = 2.5 cm Slide 35 Voyager 1 Slide 36 Saturn Diameter = 1.21 x 10 8 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 2.1 x 10 -2 m = 21 mm = 2.1 cm Slide 37 http://en.wikipedia.org/wiki/File:Saturn_during_Equinox.jpg Six moons are in the picture: Titan (5,150 kilometers across), Janus (179 kilometers across), Mimas (396 kilometers across), Pandora (81 kilometers across), Epimetheus (113 kilometers across) and Enceladus (504 kilometers across). Cassini Slide 38 Uranus Diameter = 5.18 x 10 7 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 9.0 x 10 -3 m = 9 mm Slide 39 Voyager 2 Slide 40 Neptune Diameter = 4.95 x 10 7 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 8.5 x 10 -3 m = 8.5 mm Slide 41 Voyager 2 Slide 42 Pluto Diameter = 2.30 x 10 6 m Multiply by scale factor (1.74 x 10 -10 ) Relative Diameter = 4.0 x 10 -4 m = 0.4 mm Slide 43 Hubble Telescope Slide 44 https://www.msu.edu/course/isb/202/snapshot.afs/tsao/images/scientific_method01.gif Scientific method Slide 45 What is a constellation? Slide 46 Constellations People refer to constellations as a pattern of stars Astronomers refer to constellations as specific regions of the sky In 1928, the IAU (International Astronomical Union) decided there were 88 constellations Many of the constellation names go back thousands of years Slide 47 Constellations The constellations are totally imaginary things that poets, farmers and astronomers have made up over the past 6,000 years (and probably even more!). The real purpose for the constellations is to help us tell which stars are which, nothing more. Slide 48 What is this constellation? Slide 49 Orion Bigger the star, the brighter it is Slide 50 Orion was the son of the god of the sea, Poseidon and a great hunter. One story is that he made an enemy of Hera who sent a scorpion to sting him. Orion was restored to health by Ophiuchus, the first doctor of medicine. Another story is that Artemis was tricked by by Apollo to shoot an arrow at Orion. When he died, Poseidon asked Zeus to put him among the stars. Slide 51 Slide 52 Slide 53 Slide 54 Slide 55 Ursa Major Ursa Major, the Great Bear, was identified with a bear by native American Indians of the Northeastern United States and the ancient Greeks. The name common in Britain, the Plough,seems to have a medieval origin, Another common name among northern European cultures is the Wain, a shortened form of wagon Slide 56 What are the constellations named after 14 men and women 9 birds 2 insects 19 land animals 10 water creatures 2 centaurs one head of hair a serpent a dragon a flying horse a river 29 inanimate objects Slide 57 Originally considered part of Leos tail Slide 58 Slide 59 Named after Queen Berenice II of Egypt, wife of Ptolemy III Euergetes (246 BC - 221 BC) Around 243 BC, the king undertook a dangerous expedition against the Syrians, who had murdered his sister. Berenice swore to the goddess Aphrodite to sacrifice her famous long hair if her husband returned safely. He did, she had her hair cut, and placed it in the goddess' temple. By the next morning, the hair had disappeared. To appease the furious king and queen (and save the lives of the temple priests), the court astronomer, Conon, announced that the offering had so pleased the goddess that she had placed it in the sky. He indicated a cluster of stars that at the time were identified as Leo's tail, but now have been called Berenice's Hair. Slide 60 Zodiac The zodiac is an imaginary belt in the heavens extending approximately 8 degrees on either side of the Sun's apparent path (the ecliptic), that includes the apparent paths of the Moon and the planets Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune. Slide 61 Slide 62 Slide 63 Question: Why do all the planets seem to follow the same path? Slide 64 Answer: The planets, the Earth, and the Sun all tend to fall in the same plane called the ecliptic Slide 65 Slide 66 Slide 67 Why dont all the constellations have ancient names? Slide 68 Ancient cultures such as the Greeks and Egyptians could not see the constellations in the Southern Hemisphere Slide 69 Question: Why is the path of the constellations on the zodiac not on the celestial equator? Slide 70 Answer: The rotation axis of the Earth is inclined with respect to the ecliptic Slide 71 Slide 72 Slide 73 Slide 74 Polaris is called the North Star Brightest star in the constellation Ursa Minor. 48th brightest star in the night sky It is very close to the north celestial pole, making it the current northern pole star. Polaris' altitude, or height above the horizon, is equal to an observer's latitude. Slide 75 Question: How can do know that the sun is travelling along the zodiac since you cant see stars during the day? Slide 76 Answer: One can however figure out where the sun is on the zodiac by noting which is the last constellation of the zodiac to rise ahead of the Sun or the first to set after it. Slide 77 Slide 78 Any Questions?