Join Astronomy 101 course at UMass Amherst with engaging lectures, homework assignments, office hours, and essential resources. Discover the wonders of the universe!
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Course • Course Website: • http://blogs.umass.edu/astron101-tburbine/ • Textbook: • Pathways to Astronomy (2nd Edition) by Stephen Schneider and Thomas Arny. • You also will need a calculator.
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
Homework • We will use Spark • https://spark.oit.umass.edu/webct/logonDisplay.dowebct • Homework will be due approximately twice a week
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
Metric System • 1 kilometer = 1,000 meters • 1 meter = 100 centimeters • 1 centimeter = 10 millimeters
Distances • An Astronomical Unit (AU) is the average distance between the Sun and Earth • 1 AU = 150 x 106 km = 150 x 109 m • 1 light-year is the distance light travels in a year • 1 light-year = 9.5 × 1015 meters
What is a galaxy? • 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
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
What is the Universe? • 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
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
Answer • Number of stars in universe • = (100 x 109) x (100 x 109) = 10000 x 1018 = 1 x 1022 = 10,000,000,000,000,000,000,000 • This is about the same number of grains of sand in every beach in the world
Questions: • How many of these 1022 stars have planets? • How many of these planets have life?
Assume • That the sun is the same size as a basketball • Basketball diameter = 24.4 cm • Sun’s Diameter = 1.4 x 109 m = 1.4 x 1011 cm • Scale Factor = 1.74 x 10-10 • Multiply scale factor by actual diameters of planets to get their approximate size
Mercury • Diameter = 4.88 x 106 m • Multiply by scale factor (1.74 x 10-10) • Relative Diameter = 8.5 x 10-4 m = 0.85 mm
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
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.
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.
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