THE STAR OF OUR SOLAR SYSTEM

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THE STAR OF OUR SOLAR SYSTEM
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Solar radiation travels from the sun to
the earth at the speed of light. The speed
of light is 300 000 km/s.
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The suns energy does not travel to the earth
instantaneously. It takes about 8 minutes for
solar radiation to reach the earths surface
after leaving the sun.
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http//www.youtube.com/watch?vGmWNs4QrshY
http//www.youtube.com/watch?vGmWNs4QrshY
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SUN FACTS
The sun is the only star in our solar system.

• It is 1,000,000 times larger than the earth.

• The sun accounts for 99 of the mass of our
  solar system and the planets make up the
  other 1 of the mass.

• The planets are tiny specks of matter,
  orbiting the Sun due to its gravity.

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SUN FACTS CONTINUED

• The sun is a big ball of hot gas that
  rotates once on its axis every 35 days.

• It is made of 75 hydrogen and 25 helium
  gas.

• The pressure and temperature of the core
• is so high that thermonuclear reactions take
• place.
• These reactions produce a large amount of
• energy.

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WHERE IT ALL HAPPENS - THE CORE

• Hottest part of the sun (15,000,000oC).

• Region where the suns energy is first made
  in a process called nuclear fusion.

• What is nuclear fusion?

• It is the process of merging the nucleus of
  two smaller atoms to create one larger one.

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Nuclear Fusion
In the core, the suns large gravitation force
compresses hydrogen atoms together and fuses
their nuclei creating helium atoms. Each second
the Sun converts about 600,000,000 tons of
hydrogen nuclei into helium nuclei. The fusion
reaction creates an explosion in the core that
causes massive amounts of energy to travel from
the interior outwards.
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explosion due to nuclear fusion
The collapse of the Sun from its own gravity is
balanced by the nuclear explosions at its core.
force of gravity
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An enormous amount of heat and light moves
through several layers or zones toward the outer
atmosphere of the sun.
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The ratio of hydrogen to helium is changing as
nuclear reactions continue to take place.

• The Sun formed 4.5 billion years ago, and will
  run out of fuel (hydrogen) in about 5 billion
  years.

When this happens, the Sun will explode into a
planetary nebula, a giant shell of gas that will
destroy the planets in the Solar System
(including Earth).
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How do we know what elements (e.g.hydrogen and
helium) are present in the sun and other stars?
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One of the most useful devices that astronomers
use to look at light given off by the sun and
other stars is a called a spectroscope.
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A spectroscope is a device that splits light
into a pattern of colours so that we can see them
as separate lines of colours. Works similar to a
prism.
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Each element that is heated or energized produces
its own unique line pattern of colours that can
be seen when you look through a spectroscope.
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