Download The Sun Notes File

The Sun

The sun is the nearest star.
It’s name is Sol
It takes 8 minutes for light
to reach Earth
How do we know
what the sun is made of?
Scientists use a spectrograph
Dark lines form when gases in the star’s
outer layers absorb specific wavelengths of
the light that passes through the layers
THERMONUCLEAR
FUSION CONVERTS
Proton – Proton Reaction
 (1.) 1H + 1H
(2.) 2H + 1H
2H + positron (ß+) + neutrino (v)
3He + gamma ray (y)
(3.) 3He + 3He 4He + 1H + 1H
 The energy released is similar to a hydrogen
bomb.
 Almost all of the energy is released in the form
of electromagnetic radiation.
The sun produces Energy
through nuclear fusion
Hydrogen is turned to helium and in
the process some mass is lost and
changes into energy
(1.) 1H + 1H 2H + positron (ß+) + neutrino (v)
(2.) 2H + 1H 3He + gamma ray (y)
(3.) 3He + 3He 4He + 1H + 1H
This page was copied from "http://www.astronomynotes.com Nick Strobel's Astronomy Notes
Quick Lab page 757
Trace and cut out 6 circles
Put P on one side and N on the other
Follow the directions to model the fusion
of Hydrogen to Helium
Make the diagram illustrating the 3 (5) step
process
2
E=mc
 Albert Einstein said that a
small amount of matter
yields a large amount of
energy
E = energy produced
m = mass
c2= speed of light
squared
The sun's energy allows life to
exist on earth.
Almost all
energy
transformations
can be traced
back to the sun.
It is a middle-aged star
THE SUN FORMED AROUND
5 BILLION YEARS AGO AND STILL
HAS ABOUT 5 BILLION YEARS TO
GO
The sun is actually a plasma
Plasma is another state of matter
The temperature is so high that electrons
are stripped
Layers of the Sun

Interior of the Sun
Three layers
Core
Radiative Zone—energy is transferred as
electromagnetic waves—radiation
Convective Zone—energy is transferred
through convection
The Core
Makes up about 25% of mass
Temp about 15 million Kelvins
Enormous temp and pressure cause atoms
to separate to nuclei and electrons
Nuclei are positive so push away
But high temp and pressure push them
together
Hydrogen fuses to helium
The Atmosphere
Three layers
Photosphere --light
Chromosphere--color
Corona—visible during a solar eclipse
The sun's visible surface is
called the photosphere.
Photo--Greek for
light
 It is a plasma
A plasma is
another state of
matter
It is so hot
electrons are
stripped
The Chromosphere
 The layer of the
sun's atmosphere
between the
photosphere and
the corona is the
chromosphere
 (sphere of color)
Chromosphere during an eclipse
Corona—outermost region

 extends out several
million kilometers
and merges into a
hurricane of highspeed protons and
electrons called the
solar wind.
Solar Wind
High speed electrons and electrically
charged particles called ions that stream
out into space
Flows outward to the rest of the solar
system
Section 2 Solar Activity
Page 761
Sunspots
are relatively
cool areas on
the surface
created by
strong
magnetic fields
 The sun spins on its
axis but different
latitudes spin at
different rates
 Scientists
have observed
for hundreds
of year
That is how
they know
different
latitudes
rotate at
different rates
Solar Cycles
The number and position of sunspots vary
in a cycle that lasts about 11 years
Look at Page 767
How many complete sunspot cycles are
illustrated by the graph?
How does the range of latitudes of
sunspots change over time?
How is this change related to the sunspot
cycle?
According the graph, how many sunspots
were located at the sun’s north pole?
Prominences
 Some sunspots have
prominences forming
over them
 Magnetic field lines
Solar Flares
A sudden outward
eruption of
electrically charged
particles
During a peak
sunspot cycle 5-10
solar flares may
occur each day

Coronal Mass Ejections
Parts of the corona are thrown off the sun
When the particles hit the Earth’s
magnetosphere they generate a disturbance
called a geomagnetic storm
Geomagnetic storms may interfere with
radio communications on earth
They may also lead to blackouts when
power lines become overloaded
Solar Wind
Solar Wind—our magnetic field
protects us from the solar wind
Van Allen Belts
 Van Allen Probes
(RBSP) are
researching this area
 Lower belt protons
 Higher belt-nearrelativistic particles
 The probes have
discovered a third
transient belt
Why study space weather?
 Comets
 Solar flares
 Asteroids
 Eclipses
Auroras
 colored light
produced by charged
particles in the
atmosphere that react
with the oxygen and
nitrogen in the upper
atmosphere
 Usually seen near the
poles
Why doesn’t the sun blow apart
Hydrostatic
Equilibrium
 The outward pressure
from the explosions is
balanced by the inward
force of gravity
Hydrostatic Equilibrium
Do the Directed Reading
and read Section 2