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ASTRONOMY 110 a survey of astronomy

ASTRONOMY 110 a survey of astronomy. Office Hours : Paul Coleman: MWF (9:30-10:30;11:30-12:30) Watanabe 401 pcoleman@ifa.hawaii.edu Grad st. Course details and notes : http:// www.ifa.hawaii.edu/users/gruff/default/astro110.html. ASTRONOMY 110 a survey of astronomy.

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ASTRONOMY 110 a survey of astronomy

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  1. ASTRONOMY 110 a survey of astronomy Office Hours: Paul Coleman: MWF (9:30-10:30;11:30-12:30) Watanabe 401 pcoleman@ifa.hawaii.edu Grad st. Course details and notes: http://www.ifa.hawaii.edu/users/gruff/default/astro110.html

  2. ASTRONOMY 110 a survey of astronomy Required: Any edition of: The Essential Cosmic Perspective by Jeffrey Bennett, Megan Donahue, Nicholas Schneider, Mark Voit, Addison Wesley

  3. Phasers on Stun!! Cell phones on vibrate please!

  4. 10 Question quizzes…. • If you will miss it contact me in advance… Makeups will be held on the Monday following • One question on the weekly homework problem • Two questions on the material in the readings • Last seven on the lecture material

  5. July 11Total Solar Eclipse (over South Pacific); not visible at all from Hawai‘i.  This is a very important event for the southern part of Polynesia.  The eclipse will be total over Easter Island and parts of the Cook and Tuamotu Islands and will be a very deep partial eclipse in Tahiti. September 21Jupiter in opposition.  Jupiter rises at sunset, is overhead all night, and sets at dawn.  Jupiter shines brilliantly at minus 2.93 magnitude. September 22Autumnal Equinox.  Autumn begins at 5:09 PM on September 22 Hawai‘i Standard Time.  This is a good example of an celestial event that occurs on a different day in Hawai‘i Standard Time vs. Universal Time. Since UT is ten hours ahead of HST, autumn starts at 3:09 UT on September 23 Universal Time.  On the equinox, day and night are equal (12 hours each) all over the planet. November 7Daylight Saving Time ends at 2 AM for most of North America (not observed in Hawai‘i).  As of this day, the west coast is two hours ahead of Hawai‘i and the east coast is five hours ahead of Hawai‘i. December 6Makahiki (start of the Hawaiian year).  To mark the start of the Makahiki season: 1) wait for the star cluster of the Pleiades to rise at sunset, which occurs every year on November 17; 2) wait for the new moon that follows this sunset rising of the Pleiades, which occurs in 2010 on December 5; 3) wait for the first visible crescent moon that follows this new moon.  This year, this slender crescent should be visible in the west at dusk on December 6, thus marking the start of the Makahiki season and of the Hawaiian year.

  6. Spaceship Earth • Describe the basic motions of “spaceship Earth.” • How do we know that the Universe is expanding?

  7. and Shakers… Movers… • “We never get to go anywhere” • “It costs too much to go anywhere” • Nothing could be further from the truth… During the half-minute we’ve been looking at this slide, we have traveled ~400 miles. We are whizzing through space in at least four different directions! Why don’t we feel the motion?

  8. Motion I Face the rising sun in the morning. That's our first direction of celestial movement.

  9. r Circumference = 2pr

  10. Motion I Circumference = 2pr ~ 25000 miles Time = 24 hours 1042 mph !!!!

  11. Motion II r = 1 AU = 1.5 x 1011 meters

  12. Motion II We are zooming around the sun at 64,800 mph!!!

  13. West N

  14. r Our Sun is but one of some 100 billion stars that makes up our home galaxy, the Milky Way. It takes our sun about 226 million years to circle the Milky Way. Motion III

  15. Motion III With the measured distance to the Galactic Center we calculate a speed of about 486,000 mph. Look a little above the horizon about 20 degrees west of directly south – you are traveling in that direction! The center of the Galaxy is located between the two constellations Scorpius and Sagittarius. 90 degrees away from this direction (toward Dorado) is the direction we are going as we orbit the galaxy at 135 miles per second.

  16. Motion IV Look South around midnight in june, you'll see the beautiful Southern Cross low on the horizon. Right above it is the constellation Centaurus. That's the direction our solar system and galaxy is headed at more than a million miles per hour!

  17. Take your pick: • Earth’s rotational speed = 1042 mph • Earth’s orbital speed = 64,800 mph • Sun’s orbital speed = 486,000 mph • Milky Way’s speed = 1,000,000 mph (Not to mention the expansion of the universe!) In the ~20 minutes so far for this talk, we have moved about 350 miles east and about 21,600 miles around the sun. Our solar system has moved 162,000 miles around the galaxy and we've moved about 340,000 miles closer to Hercules. For a grand total of about 420,000 miles traveled! Too bad we don't get frequent flyer miles for this.

  18. The modern Solar System

  19. How large is the Solar System? • Let’s view it to scale • say the Sun is the size of a CD (~12 cm) • then: Earth – 15 m Mars – 23 m Jupiter – 78 m Saturn –143 m Uranus – 287 m

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