Transcript The Sun

The Sun
Size, Heat, and Structure
Worship me in all of my
hotness.
But First…
 What is the significance of these
numbers when discussing the Sun?
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1.3 million
109
8
93 million
1
Objectives
 Explain the structure of the sun
and its energy source.
 Describe the effects of sunspots,
solar wind, and magnetic storms
on Earth and explain the role of
Earth’s magnetic field.
And as we study the sun
today, consider this.
How does
the sun’s
size, heat,
and
structure
affect Earth?
Everyone knows that it takes
8 minutes and 20 seconds for
light from the Sun to reach
us on Earth…but how BIG is
the Sun?
Size of the Sun
 The Sun is enormous compared to
Earth.
 Diameter of 1,400,000 km (more
than 3x the distance from Earth to
the moon; which is the longest
distance humans have traveled in
space)
How many Earths
would fit inside a
hollow sun?
Over one
million!
How long would it take a
jet to circle the Sun?
 2 months
 That is if you were flying at
Mach 3 (3 times the speed
of sound)
But remember…
 The Sun is an average sized
star.
 The largest known star, Epsilon
Aurigae, is 4,000 x larger than
the sun.
Our sun is known as a:
Main Sequence Star
Where does the Sun get
its energy?
 Fusion -- the combining
of lighter elements to form
a heavier one.
 Hydrogen atoms are fused
into Helium atoms.
Hydrogen atoms fuse
together to make a helium
atom.
 But a neutron is released
along with a lot of energy.
 This left over matter
2
becomes energy. (E=mc ).
You da man Albert!
The matter that makes up
the sun is very high energy
gas under intense heat and
pressure.
 This matter is plasma.
 Plasma – the fourth state of
matter that consists of flowing
electric charge
The Sun’s Layers
 No one has observed the interior of
the sun but models have been
produced.
 The energy produced inside the sun
pushing outward is balanced by the
gravity drawing the outer layers
inward.
The Sun’s Core
 The plasma in the core, made
mostly of hydrogen and helium,
is 100x more dense than water.
 Temp = 15,600,000 degrees C
Radiative Zone
 Another layer of plasma that is
cooler and just outside the inner
core.
 8,000,000 deg C
Convection Zone
 1,500,000 deg C
 Rising and falling currents of
plasma carry energy to the sun’s
surface where it is radiated out
into space as sunlight
Photosphere
 The visible surface of the sun
 6,000 deg C
Chromosphere
 The sun’s “atmosphere”
 Thousands of kilometers above the
photosphere
 20,000 deg C
 This high temperature causes the
hydrogen to emit reddish light.
Corona
 The thin outer part of the sun’s
atmosphere
 A million times less bright than the
photosphere
 Still hot at 1,000,000 oC
 The Corona is the HOTTEST layer
of the atmosphere.
What features of the sun are
visible during a solar eclipse?
 The Corona and the chromosphere
Sunspots
 The sun rotates.
 Scientists are able to prove this
because sunspots appear to
move!
 Dark spots on the photosphere
 Some are barely visible
 Some are 4x the size of Earth
What causes sunspots?
 Sunspots occur where the sun's
magnetic field loops up out of the
solar surface and cool it slightly,
making that section less bright.
Sunspots are actually
pretty hot and bright.
 But they are dark because the
surrounding photosphere is
so much hotter and brighter.
 Sunspots are 3,000 o C and
the sun’s surface is 6,000 oC.
The Sunspot Cycle
 Sunspots go through periods of
high and low activity.
 Peak activity happens every 11
years or so.
Why study sunspots?
 They can tell us things about the
Sun’s magnetic properties.
 And, because someone wants to!
Solar Wind
 A constant stream of electrically
charged particles
 These particles are mostly
protons and electrons
 Luckily, the Earth has its own
magnetic field that deflects solar
wind and solar flares
Why would solar flares and
solar wind be harmful to us?
 These charged particles could cause
cancer.
 Growth of all living things would be
inhibited.
 As solar wind blows past earth,
particles interact with the earth’s
upper atmosphere producing a
display of colors called…..
Auroras
 Beautiful displays of color and light
appearing in the sky
 They occur when solar wind
interacts with the magnetic fields of
the Earth in the upper atmosphere.
 Also called the Northern Lights or
Southern Lights
Magnetic Storms
 In March 1989, the sun emitted a
huge solar flare that made TV
receptions fade, caused power
outages, and made garage
doors malfunction.
 National Geographic Solar Blast
Why does the sun look red
sometimes?
 When the Sun is low on the horizon,
its light has to travel farther to reach
you. This allows red, a longer
wavelength, to be seen.
 When the Sun is high on the horizon,
blue light is scattered, which allows
you to see a yellow sun.
When will the Sun die?
 The sun is now 4.5 billion years old and will
die (burn out of fuel) in 5 billion years.
 It will go from a red giant to a yellow dwarf.
 It will get so big at the end of the giant
stage that its diameter will likely reach
Earth’s orbit.
 Better get cho SPF on?!
The Sun 101
National Geographic Video