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Transcript
The Sun Miss Butler Astronomy 12 March 22, 2010 http://www.luminousnuminous.com/blog/wp-content/uploads/2009/05/sun_tour.jpg THE SUN • SOL • The Sun’s scientific name is Sol (hence the name “Solar System”) http://upload.wikimedia.org/wikipedia/commons/d/d9/Yohkohimage.gif http://upload.wikimedia.org/wikipedia/commons/thumb/9/9d/Sol_de_Mayo-Bandera_de_Argentina.svg/504px-Sol_de_Mayo-Bandera_de_Argentina.svg.png WHAT IS THE SUN? • • • • • Centre of the Solar System A foci for all planets in the Solar System A yellow star Luminous Composed of plasma (an ionized gas) made mostly of hydrogen and helium. http://www.bnsc.gov.uk/assets/channels/education/ae/solar.gif OUR STAR’s SIZE • 1,400,000,000 m diameter • The Sun could hold 1.3 million Earth’s! http://www.answersingenesis.org/assets/images/articles/tba/chapter-one/sun-moon-earth.jpg THE SUN’S MASS • 750 times the mass of all of the Solar System’s planets put together • Between 98% and 99% of the Solar System’s mass • 332,830 times the mass of Earth! • 1.989 x 1030 kg (1,989,000,000,000,000,000,000,000,000,000kg) OUR STAR – KEY FACTS • DENSITY: 1410 kg/m3 – At the Sun’s centre, the density is more than 150 times that of water! • TEMPERATURE: – Average temperature: Approximately 6270Kelvin – 6000°C – This is the same temperature as the Earth’s core! • ATMOSPHERE: – Made up of immense clouds of glowing gas – Stretches far into space – Can only be seen during total solar eclipses OUR STAR • Surface temp = 5500°C • Core temp = 15 million°C http://www.rise.org.au/info/Res/sun/image004.jpg KEY FACTS • The obliquity (or axial tilt) of the Sun is 7.25° http://en.wikipedia.org/wiki/File:AxialTiltObliquity.png KEY FACTS • 1) The Sun has no moons or rings. • 2) The Sun has natural satellites – the planets, dwarf planets, and smaller celestial bodies • 3) Distance from Earth: 1 AU • 4) The closest planet is Mercury • 5) The farthest planet is Neptune Classifying the Sun • 1) “Jovian” – made of gases • 2) “Classical” – can be seen with the naked eye – Scientists used to think the Sun was a planet! GRAVITATIONAL PULL • Acceleration due to gravity = 274 m/s2 • Compared to Earth’s 9.81 m/s2 http://www.kudzuacres.com/wwow/lessons/weather/oceansurface_files/image003.jpg GRAVITATIONAL PULL • Fg=mg • Earth • Fg = 70 x 9.81 = 686.7 N Sun Fg = 70 x 274 = 19,180 N OUR STAR – TIMES! • The core rotates at the same rate but the outer parts of the Sun do not! • 34 Earth days to rotate at Poles • 25 Earth days to rotate at Equator • There is no period of revolution… http://www.lcsd.gov.hk/CE/Museum/Space/EducationResource/Universe/framed_e/lecture/ch11/imgs/rotation.gif OUR STAR – TIMES! • Our Sun is estimated to be approximately 4.5 billion years old. • It should last another 5 billion years. • Made initially from a cloud of dust. • Matter fell inwards, creating heat, eventually causing nuclear fusion and producing its own light and energy. BRIGHTNESS • −26.74 visual magnitude • Brightest object in sky from Earth STUDYING THE SUN • Ancient civilizations studied the sky and stars • Many had Sun gods – – – – – – – Amaterasu (Japan) Helios, Apollo (Greek) Freyr, Sol (Norse) Huitzilopochtli (Aztec) Inti (Inca) Liza (West African) Re/Ra (Egyptian) STUDYING THE SUN • In 1609 Galileo built his first telescope • He saw Sunspots http://www.telescope1609.com/images/GalileosTelescope.jpg http://www.norcalblogs.com/watts/images/sunspots_earth_size_big.jpg STUDYING THE SUN • 1960’s • PIONEER 5 to 9 • Orbited the sun – Solar wind – Solar flares – Magnetic fields http://abyss.uoregon.edu/~js/images/pioneer6.jpg STUDYING THE SUN • 1974 & 1976 • HELIOS • High-velocity passes close to Sun’s surface – Solar wind – Magnetic field http://thelongestlistofthelongeststuffatthelongestdomainnameatlonglast.com/images4/helios.JPG STUDYING THE SUN • 1980 • SOLAR MAXIMUM MISSION – X-rays – Gamma rays – Ultraviolet radiation – From flares and sunspots http://library01.gsfc.nasa.gov/gdprojs/images/smmrepair.jpg STUDYING THE SUN • 1990 • ULYSSES • 1st polar orbiting probe • Still in operation • “Fly by” http://science.nasa.gov/headlines/y2008/images/northpole/Ulysses_spacecraft.jpg STUDYING THE SUN • 1991 • YOHKOH • Earth-orbiting satellite observed high-energy radiation http://heasarc.gsfc.nasa.gov/Images/objects/heapow/solar_system/yohkoh_solar_cycle.jpg STUDYING THE SUN • 1995 • SOHO • Studies the Sun’s interior and surface http://msnbcmedia3.msn.com/j/msnbc/Components/Photos/051129/051129_soho_hmed2p.h2.jpg STUDYING THE SUN • 1998 • TRACE • Studies the Corona http://library01.gsfc.nasa.gov/gdprojs/images/trace.jpg SUN MYTHS • “What if the sun collapses into a black hole? • Bad Astronomy: If the Sun collapses into a black hole, the Earth and all the other planets will get sucked in. • Good astronomy: If the Sun were to collapse into a black hole, we would feel no difference in the gravity as measured at the Earth. “ (Note the quotations as I have copied this!!!) http://www.badastronomy.com/bad/misc/black_hole_sun.html Sources • • • • • • • • • • • • • • • • • • • • • • http://z.about.com/d/space/1/5/Y/Q/sun_tour.jpg www.answers.com/topic/hertzsprung-russell-diagram http://www.answersingenesis.org/assets/images/articles/tba/chapter-one/sun-moon-earth.jpg http://www.astro.washington.edu/labs/clearinghouse/labs/Propsun/images/chang_sun2.gif http://hometown.aol.com/falconmaster29/downloads/SolarFlare.jpg http://www.nasa.gov/images/content/171925main_heliolayers_label_516.jpg http://www.space.gc.ca/asc/img/trans_mass_n_weight.jpg http://www.geocities.com/ominaga2/amaterasu_classic2.jpg http://www.maicar.com/GML/000Free/000Apollo/image/apollo3837.jpg http://www.hurstwic.org/history/articles/mythology/myths/pix/freyr.jpg http://www.class.uh.edu/courses/engl3396/jtchris2/Huitzilopochtli.jpg http://www.unique-southamerica-travel-experience.com/images/inti-copia.jpg http://www.telescope1609.com/images/GalileosTelescope.jpg http://astronomy.neatherd.org/Swedish%20sunspots1.jpg http://abyss.uoregon.edu/~js/images/pioneer6.jpg http://www.deutsches-museum.de/uploads/pics/helioskl_05.jpg http://library01.gsfc.nasa.gov/gdprojs/images/smmrepair.jpg http://www.sflorg.com/missionnews/ulysses/images/immn081707_01_01.jpg http://msnbcmedia3.msn.com/j/msnbc/Components/Photos/051129/051129_soho_hmed2p.h2.jpg http://library01.gsfc.nasa.gov/gdprojs/images/trace.jpg http://en.wikipedia.org/wiki/Sun Information from “Universe: the definitive visual guide” senior editor: Peter Frances