Download The Sun

The Sun
Unit 5
PESS 2
Energy from the Sun
• Electromagnetic energy is a
type of energy that can travel
through space an example is
visible light
• Light travels in wavelengths
– There are many things that
travel in wavelengths (radio
waves, microwaves, ultraviolet
rays, x-rays)
• The electromagnetic spectrum
breaks visible light down into
the colors that make it up
– When you shine light through
a prism you can see the
different colors of visible light
Electromagnetic Radiation
• Visible light is
composed of red,
orange, yellow,
green, blue and violet
– like a rainbow
Energy from the Sun
• In a process called nuclear
fusion the sun gives off
electromagnetic energy
• Nuclear fusion can only occur
at extremely high
temperatures (~15 million °C)
– Helium and hydrogen atoms
fuse together giving off an
enormous amount of energy
(enough to supply the solar
system for billions of years!)
• There is enough helium and
hydrogen in the sun to last
about 10 billion years – the
sun is only about 5 billion
years old
Measuring our Solar System
• Since the solar
•
system is so large
scientists developed
the unit called an
astronomical unit or
au
The distance between
the sun and Earth is
1au
The Sun’s Interior
• Consists of: Core, Radiation
zone, Convection zone
• Core
– Where nuclear fusion occurs
– About 400,000km
• Radiation zone
– Region of highly compressed
gases
– Takes energy “light” about
10,000 years to pass through
• Convection zone
– Convection currents move the
energy to the atmosphere
The Sun’s Atmosphere
• There are 3 layers – the
photosphere, the
chromosphere and the corona
• The Photosphere
– The inner layer
– Technically, the “surface”
– About 5800K and 500km thick
• The Chromosphere
–
–
–
–
The middle layer
Gives off a reddish glow
About 10,000K
Visible during a total solar
eclipse
The Sun’s Atmosphere
• The Corona
– The white halo around the
sun
– Visible on Earth only during
eclipses or by special
telescopes
– Sends out a stream of
electrically charged
particles called solar wind
– The Earth’s atmosphere
normally blocks out solar
wind, but near the north
and south poles some
particles enter creating
auroras
– About 1 million K
Features of the Sun
• The sun rotates on its
axis, just like all the other
planets in the solar
system
• Sunspots
– Small, dark spots on the sun
(small for the sun because
they are about the size of
Earth)
– Sunspots are areas of gas that
are cooler than the gases
around it – since they are
cooler they do no give off as
much light and appear dark
Features of the Sun
• Scientists believe that the
number of sunspots change
over 10 years or so – meaning
that the amount of energy
produced by the sun also
changes
• Prominences
– A group of sunspots that link
together and create reddish
loops
– If a prominence is near the
edge of the sun scientists can
actually see them stick out
from the sun’s surface
Features of the Sun
• Solar flares
– When sunspots suddenly
connect and release a large
amount of energy into space
– The gases contract an heat to
even greater temperatures
causing hydrogen gas to
explode into space
– Solar flares can cause
magnetic storms in the upper
atmosphere of Earth
disrupting radios, telephones,
television, and causing
electrical problems