Download PP 23-The Solar System

The Sun
The Solar System
Our sun is a medium sized star which is the center
of our solar system.
It is the closest star to the earth at about 93,000,000
miles away.
It has a diameter of about 1,400,000 kilometers.
The Sun is about 330,000 times as massive as the
Earth.
1.3 million Earths can fit inside the Sun!
The Sun by itself accounts for about 99.8% of the
Solar System's mass.
Its gravitational pull holds the planets, comets, etc.
orbiting about it.
The Sun plays a key role in the Earth’s seasons.
The sun is our source of energy.
Without the heat and light of the sun, there would
not be life on earth.
Solar energy is used by green plants for
photosynthesis.
Solar heating is the source of the energy of moving
air.
Solar energy also effects the process of the water
cycle.
All stars get their energy from fusion.
Fusion is the combining of the nuclei of lighter
elements to form a heavier element.
The extra mass is converted to energy according to
Einstein's equation E=mc2.
Since its birth the Sun has used up about half of the
hydrogen in its core.
The Sun is about 4.5 billion years old.
With all this intense heat and pressure, these
elements exist as a plasma.
The Sun has an average temperature of 10,300° F
Sunlight is very bright, and looking directly at the
Sun with the naked eye for brief periods can be
painful.
The sun is nearly all hydrogen and helium, with
traces (less than 2% by mass in total) of elements
with heavier nuclei.
Lab: Elements in the Stars
The Sun’s Layers
1: Core
The Sun’s core is the place where energy is
produced nuclear fusion.
It's the hottest and most dense part of the Sun,
having a temperature of 1.5 million °C and a density
150 times greater than that of water.
1: Core
2: Radiative Zone
Around the core is the radiative zone. Though not as
dense as the core, it is still so dense that photons
take around 170,000 years to pass though this layer.
1: Core
2: Radiative Zone
3: Convective Zone
This zone occupies the outer 1/3 of the Sun's body.
It is the outer most layer of the Sun’s surface.
This is a layer of less density that constantly churns
and swells, driven by the enormous heat being
generated below.
1: Core
2: Radiative Zone
3: Convective Zone
4: Photosphere
The photosphere is made of hydrogen at the
temperature of 5500°C.
It is the lowest layer of the Sun’s atmosphere, the
visible surface of the Sun.
Most of the Sun’s emitted light comes from this
layer.
1: Core
2: Radiative Zone
3: Convective Zone
4: Photosphere
5: Chromosphere
The chromosphere (which means "colored sphere")
is a transparent layer, just above the photosphere.
The temperature of the chromosphere increases
from 4300 degrees to more than 400,000 degrees.
1: Core
2: Radiative Zone
3: Convective Zone
4: Photosphere
5: Chromosphere
6: Corona
The outermost layer of the Sun’s atmosphere is the
corona.
This layer is so incredibly hot, over 2 million° C.
1: Core
2: Radiative Zone
3: Convective Zone
4: Photosphere
5: Chromosphere
6: Corona
7: Sunspots
Sunspots are "cool" regions, only 3800 K.
They look dark only by comparison with the
surrounding regions.
Sunspots can be very large, as much as 50,000 km
in diameter.
Sunspots are caused by he Sun's magnetic field
poking through the Sun.
1: Core
2: Radiative Zone
3: Convective Zone
4: Photosphere
5: Chromosphere
6: Corona
7: Sunspots
8: Granules
Granules are the thousands of bumps on the Sun’s
photosphere.
1: Core
2: Radiative Zone
3: Convective Zone
4: Photosphere
5: Chromosphere
6: Corona
7: Sunspots
8: Granules
9: Prominence
Prominence is an arc of gas that is ejected from the
photosphere and condenses and rains back to the
surface.
Also associated with sunspots are Solar Flares.
The temperature of gases is around 6,000°C.
During active periods in the solar cycle, large
numbers of sunspots, prominences and flares
occur.
The Sun also gives off solar wind streaming off into
space.
The particles move very fast - over 150 miles per
second.
Thanks to the Earth’s magnetic field, you can't feel
solar wind, but you can see it.
Unlike the Earth, Mars does not have a magnetic
shield to protect it from the solar wind, so particles
from the Sun may have played a crucial role in
shaping the Martian atmosphere making it a dry
planet.
The outer layers of the Sun exhibit differential
rotation.
At the equator the surface rotates once every 25.4
days; near the poles it's as much as 36 days.