1. Astronomy Introduction

2. What is Astronomy? The scientific study of celestial (sky/space) objects like stars, comets, planets, and galaxies Astronomy is NOT astrology

3. Why study astronomy? The Sun provides our energy to live. Radiation from the Sun powers our atmosphere and weather. Earth's spin gives us day and night. Axial tilt gives us the seasons. The Sun and Moon cause the tides. The Moon causes eclipses. The constellations are used for navigation. Earth's orbit provides our annual calendar. The phase of the Moon fixes the date of Easter Sunday. Ultra violet radiation from the Sun gives us a suntan. Solar Flares cause the auroras and affect our radio transmissions. New worlds to explore and colonize

4. LIFE ON OTHER WORLDS??

5. Scientific Theory and the Scientific Method Scientific theories: Must be testable Must be continually tested Should be simple

6. What can we Observe in the Night Sky? Stars Stars –large spheres of incandescent (glowing) gas –Energy comes from nuclear fusion –H + H → He + energy (e=mc 2 ) –E.g. Polaris, Sun, Betelgeuse, Procyon, Regulus

7. Constellations Constellations –Regions of space –88 regions –E.g. Ursa Major, Ursa Minor, Pegasus –Gemini, Leo, Capricornus, Scorpius

8. Asterism Asterism –Aster = star –Group of stars that make a pattern –Big Dipper, Little Dipper, Great Square, Orion’s Belt, Summer Triangle

9. Galaxy Galaxy –Cluster of billions of stars –Milky Way- our galaxy –Andromeda Galaxy (M31)

10. Spiral Galaxy NGC 4414 -

11. Nebula Nebula –Cloud of gas and dust in space –M42: Great Nebula in Orion (nursery for stars) –Eagle Nebula

12. Eagle Nebula (M16) These eerie, dark pillar-like structures are actually columns of cool interstellar hydrogen gas and dust that are also incubators for new stars. They are part of the "Eagle Nebula", a nearby star-forming region 7,000 light-years away in the constellation Serpens. These eerie, dark pillar-like structures are actually columns of cool interstellar hydrogen gas and dust that are also incubators for new stars. They are part of the "Eagle Nebula", a nearby star-forming region 7,000 light-years away in the constellation Serpens. The picture was taken on April 1, 1995 with the Hubble Space Telescope Wide Field and Planetary Camera 2. The picture was taken on April 1, 1995 with the Hubble Space Telescope Wide Field and Planetary Camera 2. Dr. Jeff J. Hester, Dr. Paul A. Scowen, Arizona State University, STScI/AURA, NASA (1995) Dr. Jeff J. Hester, Dr. Paul A. Scowen, Arizona State University, STScI/AURA, NASA (1995)

15. North American Nebula (NGC 7000)

16. In Cygnus close to Deneb In Cygnus close to Deneb Emission nebula Emission nebula Discovered in 1700s by William Herschel Discovered in 1700s by William Herschel 50 ly across 50 ly across About 1500 ly away About 1500 ly away

17. Horsehead Nebula (Barnard 33) In Orion In Orion Dark nebula Dark nebula 1500 ly away 1500 ly away 3.5 ly across 3.5 ly across Discovered 1888 Discovered 1888

18. Ring Nebula (M57) In Lyra In Lyra Planetary nebula Planetary nebula 2000-2500 ly away 2000-2500 ly away

19. Forms when star blows off gas- white dwarf star left behind

20. Crab Nebula (M1, NGC 1952) In Taurus In Taurus Remnant of supernova observed by Chinese in 1054 Remnant of supernova observed by Chinese in 1054 Hubble Space Telescope image of the Crab Nebula. High-energy particles accelerated by the Crab pulsar, a neutron star spinning with a period of 33 ms at the center of the remnant, cause the bluish glow of the interior. The outer filaments are the tattered remains of the star and consist mostly of hydrogen. Hubble Space Telescope image of the Crab Nebula. High-energy particles accelerated by the Crab pulsar, a neutron star spinning with a period of 33 ms at the center of the remnant, cause the bluish glow of the interior. The outer filaments are the tattered remains of the star and consist mostly of hydrogen. http://www.mpa-garching.mpg.de/~thj/popular/Crab_Nebula.jpg

21. Planets Bodies that revolve around the Sun Bodies that revolve around the Sun Have enough gravity to make themselves round Have enough gravity to make themselves round Cleared out the region in their orbit Cleared out the region in their orbit

22. Eight planets Mercury Mercury Venus Venus Earth Earth Mars Mars Jupiter Jupiter Saturn Saturn Uranus Uranus Neptune Neptune

23. Could there be more planets that we cannot see?

24. Dwarf Planets Pluto Pluto Far from the Sun Far from the Sun Not round Not round ‘Kuiper Belt objects’ ‘Kuiper Belt objects’

25. Comets Orbit the Sun in eccentric paths Orbit the Sun in eccentric paths ‘dirty snowballs’ ‘dirty snowballs’ E.g. Halley (1910, 1986, 2061) E.g. Halley (1910, 1986, 2061)

26. Asteroids Large chunks of rock Large chunks of rock Live between Mars and Jupiter Live between Mars and Jupiter Largest: Ceres Largest: Ceres

27. Moons Satellites of a planet Satellites of a planet (the planet is the ‘primary’- it goes around the Sun) (the planet is the ‘primary’- it goes around the Sun)