Download The Sun

Here Comes the Sun!!
Chapter 14
Section 2
Page 545
Miss Sullivan
Rm B2
The Sun
• The sun is the closest star to Earth
• It is approximately 93 million miles or 150
million kilometers away (1 astronomical
unit)
• It provides almost all of the energy for life
on Earth
• It also accounts for 99.8% of the total
mass of our solar system
The Sun’s Energy
• The sun’s energy is produced through
nuclear fusion.
• Nuclear fusion is when two smaller
atomic nuclei (hydrogen) are fused or
joined together to form a more massive
nucleus (helium) and releasing energy.
• This fusion happens only under intense
pressure and temperature
Nuclear Fusion
• During nuclear fusion, two atomic nuclei
collide and fuse.
Forces in Balance
• Nuclear fusion in the sun’s core
produces an incredible amount
of energy.
– This energy causes gas ions within
the sun to move very fast,
generating a tremendous pressure
pushing outward from the core.
– This pressure would cause the sun
to explode if it weren’t balanced by
an equal and opposite force The
balancing force is gravity.
– The weight of matter pushing
inward and the outward pushing
pressure are balanced throughout
the sun.
The Layers of the Sun
The sun has an
interior and an
atmosphere,
each of which
consists of
several layers.
The Sun’s Interior
• Convection Zone --where hot gases form
convection currents
• Radiation Zone --- a
place of condensed
gases that transfer
electromagnetic
radiation
• The Core --- where
nuclear fusion takes
place
The Sun’s Atmosphere
The sun’s atmosphere
has 3 layers:
– The Photosphere
the sphere that “gives off
light”
– The Chromosphere
a thin layer of color
– The Corona
the outer white halo that
extends millions of
kilometers into space
The Sun
• Features on or above the sun include
sunspots, prominences, and solar flares.
Sunspots
• Sunspots look like small dark
areas on the sun’s surface
(some are actually as big as the
Earth!)
• Sunspots are areas of gas on
the sun that are cooler than the
gases around them.
• Cooler gases don’t give off as
much light as the hotter gases.
• Sunspots actually occur in
cycles and can be linked with
weather here on Earth!
Sunspots and Weather
• Evidence that supports that theory that
sunspots cycles influence weather include:
– Little Ice Age: most parts of the world experienced
cold harsh weather.
• Little Ice Age is associated with low sunspot activity
between 1645-1715 (these are called minimums)
• Low sunspot activity occurs every 500 years, perhaps
another Little Ice Age will occur in 2050! (41 years from
now…how old will you be?)
Prominences
• Prominences:
Reddish loops of
ionized gas that
link different parts
of sunspot regions.
Solar Flares
• Solar Flares: When
prominences
suddenly connect, a
large amount of
energy is released
causing huge
explosions of
hydrogen (Solar
Flares)
Solar Wind
• Solar flares cause an
increase in solar wind that
extends the corona into
space
• An increase is solar winds
can cause electromagnetic
effects on Earth: auroras,
disrupt communications,
cause electrical problems
Homework
• Read Chapter 14, Section 2
• Do the questions at the end of the section,
page 550