Studying the Sun

1
Studying the Sun

• An Introduction

2
Why Study the Sun?

• The Climate Connection
• Space Weather
• The Sun as a Star
• The Sun as a Physical Laboratory

3
The Climate Connection
http//solarscience.msfc.nasa.gov/whysolar.shtml
4
Ultraviolet (UV) View of the Sun

• UV view of the sun, taken by the SOHO satellite.
• UV light causes sunburns
• This is a false colour image since humans cannot
  see UV with their eyes.

NASA/SOHO
5
Hurricane Katrina 28 Aug 2005
The energy that drove Katrina ultimately came
from the sun
http//www.katrina.noaa.gov/images/katrina-08-28-2
005.jpg
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Solar Wind and Space Weather
This is an example of weather on earth, but
weather in space is very different. What is going
on here?
http//torontoist.com/attachments/toronto_kevinb/2
006_11_23FogInToronto.jpg
7
The solar wind and space weather begins with the
suns corona expanding out into space

• Corona is the outer atmosphere
• A special camera blocks the light from the disc
  of the sun

http//sohowww.nascom.nasa.gov/gallery/bestofsoho.
html
8
Solar Wind 20 May 2008 903 UT
Speed 377 km/s Density 6.35 protons/cm3
SOHO satellite
Try expressing the density in a sentence.
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The solar wind blows the tails of comets away
from the sun
Comet Hale-Bopp
Photo Credit A. Dimai and D. Ghirardo, (Col
Druscie Obs.), AAC
10
The solar wind is a danger to astronauts and
satellites
Canadian RADARSAT-1
Canadian astronaut Hadfield attached to Canadarm
http//www.space.gc.ca/asc/app/gallery/results2.as
p?sessionimage_id6
http//www.space.gc.ca/asc/app/gallery/gallery/hig
ht/STS-100-115.JPG
11
The earths magnetic field without interference
of Sun

• Is there really a bar magnet in the earth?
• Why is the magnets south end at the north pole?

http//stargazers.gsfc.nasa.gov/resources/magnet_i
n_space.htm
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Notice how the magnetic and geographic poles are
different.
What defines the geographic north pole?
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Solar wind distorting the earths magnetic field
Not to scale artists depiction.
http//en.wikipedia.org/?titleGeomagnetic
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Aurora Borealis seen from space
Credit NASA
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Aurora Borealis seen from rural Eastern Ontario,
2004
Credit Terence Dickinson, Editor SkyNews magazine
16
Aurora Borealis seen in rural Eastern Ontario,
2004
Credit Terence Dickinson, Editor SkyNews magazine
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Aurora Borealis seen from Wapusk National Park,
Manitoba
http//i-eclectica.org/category/imagery/
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Perseus Cluster of Galaxies
Our sun can help us understand the billions of
stars in the billions of distant galaxies
those in our own galaxy, the Milky Way
Canada-France-Hawaii Telescope / Coelum
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Milky Way Galaxy

• Our own galaxy has billions of stars, our sun
  being just one of them!
• A photo from a location with low light pollution

http//en.wikipedia.org/wiki/ImageMilky_Way_IR_Sp
itzer.jpg
20
Inside an Experimental Fusion Reactor(Joint
European Torus reactor)
attempting to recreate the sun in a lab to find
a new source of energy
http//en.wikipedia.org/wiki/ImageJointEuropeanTo
rus_internal.jpg
21
This magnet has unchanging magnetic lines
http//www.teachnet-lab.org/ps101/bglasgold/magnet
ism/magnetism2.jpg
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The twisting of the suns magnetism
Differential rotation different speeds at
different locations above and below equator twist
the lines of magnetism
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Sun vs Earth Magnetism
Suns magnetism is complicated
Earths is relatively simple
http//www.windows.ucar.edu/tour/link/sun/sun_mag
netic_field.html
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The Suns complicated magnetism

• The suns magnetism, always changing, is more
  complicated than the Earths magnetism
• the suns magnetism forms these prominences into
  loops

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Flares are formed by magnetic lines
Titanic solar flares dwarf the earth by comparison
NASA/SOHO
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Galileo 1564-1642
was credited with discovering sunspots in 1612
using a telescope, but Chinese astronomers may
have been the first using the naked-eye
http//www.galileo-galilei.org/pictures-galileo-ga
lilei.html
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Sunspots
NASA/SOHO satellite image of sun with many
sunspots
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Sunspot Close-up

• Granules are hot blobs of gas up to 1000 km wide
• Dark spot is a sunspot where magnetism squashes
  the blobs

http//solarscience.msfc.nasa.gov/feature1.shtml
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Sunspot Magnetic Field Polarity
http//solarscience.msfc.nasa.gov/feature1.shtml
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Can you see any patterns in the data?
Sunspot Activity
http//sidc.oma.be/sunspot-index-graphics/sidc_gra
phics.php
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If the sun was as big as a basketball, earth
would be only 2.2 mm in diameter
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Pinhole camera geometry
light ray
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Pinhole camera optics
Diameter of object
Diameter of image
Light rays