The SunMiss 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/thumb/9/9d/Sol_de_Mayo-Bandera_de_Argentina.svg/504px-Sol_de_Mayo-Bandera_de_Argentina.svg.png

http://upload.wikimedia.org/wikipedia/commons/d/d9/Yohkohimage.gif

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 Sun

• Fg = 70 x 9.81 Fg = 70 x 274

= 686.7 N = 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.jpghttp://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

sunspotshttp://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