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The Sun and Our Earth
The Structure of Our Sun
The Energy of Our Sun
The Activity of Our Sun
The Affects of Our Sun on Earth
The Structure of the Sun
The Sun’s Interior

The core
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at the center of the sun
ionized gas
extremely dense (10x denser than iron)
electrons are stripped away from nuclei
nuclear fusion occurs here
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The Radiative Zone
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zone surrounding the core
energy moves outward through this zone from
the core in electromagnetic waves
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Convective Zone
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surrounds the radiative zone
energy produced in the core moves through
this zone by convection
hot gases carry energy to the sun’s surface.
The Sun’s Exterior
or the Atmosphere of the Sun

The Photosphere
 Made
up of gases from the Convection Zone
 The energy given off is in the form of visible light

The Chromosphere
 Glows
with reddish light
 gases form narrow jets of hot gas that shoot
outward and then fade away

The Corona
 Huge
region of gas = crown
 Not very dense
 Has a strong magnetic field
The Energy of Our Sun

Composition:
Gases that make up the sun are:
Hydrogen – 90%
Helium – 8%
Gases create energy through nuclear
fusion.
Nuclear fusion: the process of combining
the nuclei of small atoms to form more massive
nuclei. A small amount of matter is destroyed or
converted into energy.
Nuclear Fusion
Nuclear Fusion:
Step 1: Two protons from hydrogen
nuclei collide and fuse. The positive charge of
one of the protons is neutralized as that proton
emits a particle. That proton then becomes a
neutron and now there is a proton-neutron pair.
Step 2: Another proton combines
with this proton-neutron pair to produce a
nucleus made up of two protons and one
neutron.
Step 3: Two nuclei made up of two
protons and one neutron collide and fuse. Two
protons are released. The two protons and two
neutrons fuse together to form a helium nucleus.
The Sun’s Magnetic Field
Movement of the Convection Zone
and the rotation of the sun
produces magnetic fields on the
sun.
Activity of the Sun
Sunspots
Solar Ejections
Sunspots
Sun spots
The Cause:
 Magnetic fields causes the convection to
slow in the convection zone. Slower
convection causes a decrease in the
amount of gas that is transferring energy
from the core to the photosphere.
 Because less energy is transferred, some
regions of the photosphere are cooler than
the surrounding region
Sunspots
Appearance
 These areas appear darker
 These areas will appear more grainier
 These areas are cooler
 These areas will have a stronger
magnetic field
Sunspots
The Sunspot Cycle
 Number and position of sunspots varies
every 11 years.
 The cycle begins when the number is low
and starts an increase in the amount.
 The cycle ends when the number reaches
a minimum again.
 Sunspots appear in groups midway
between the sun’s poles and the sun’s
equator
 Sunspots tell us the sun rotates
Sunspot
The Graph of Sunspots
Solar Wind
Electrons and electrically charged particles
called ions escape the solar magnetic field
and move into space
Solar Ejections
What are they?
Atomic particles are emitted by the sun
during solar events
What solar events?
Prominences
Solar Flares
Coronal Mass Ejections
Solar Ejections
Prominences:
 Great clouds of sun’s gases from the
photosphere
 They are caused by disturbances in the
magnetic field
 They form Huge arches high above the
sun’s surface
Solar Ejections
Solar Flares:
 A sudden eruption of electrically charged
particles
 It is a release of energy stored in the
magnetic field of the sunspots
 There can be formation of coronal loops
 Some particles can escape into space.
Solar Ejections
Coronal Mass Ejections:
 Electrically charged particles of the sun can
escape into space.
 These particles are parts of the corona.
 CME’s strike the Earth’s magnetosphere
(Earth’s magnetic field)
 CME’s can cause a disturbance in the
Earth’s magnetic field called
geomagnetic storms
The Sun Affects Our Earth
Geomagnetic Storms
Auroras
Sunspots and Climate
Geomagnetic Storms
Caused by coronal mass ejections –
CME’s
 Sun’s particles strike the Earth’s magnetic
field generating geomagnetic storms
 Geomagnetic storms can interfere with
radio communications, damage satellites,
can lead to blackouts
 Small storms occur each month and
severe storms occur less than once per
year

Auroras
Electrically charged particles from the sun
cluster at the Earth’s poles.
 These particles excite the atoms and gas
molecules in the upper atmosphere
causing them to glow
 Known as the aurora borealis or northern
lights.

Climate Changes from Sunspots
Affect on Earth
 The fewer the sunspots, the cooler the sun
and the cooler the climate
 The more the sunspots, the hotter the sun
and the warmer the climate
 Sunspots have a direct effect on the
Earth’s climate