Origin of the Solar System

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Origin of the Solar System
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Origin of the Solar System
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• The solar system was formed by a gravitational
  fall of a cloud of gas made up of hydrogen,
  helium and dust.

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Orbit of the Planets 1
Mercury
Venus
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Mars
Earth

• The four inner planets are rocky.
• They are kept in an orbit around the sun by
  gravity.

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Orbit of the Planets 2
Saturn
Jupiter
Neptune
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Uranus

• The other planets are gas giants.
• Pluto is no longer considered to be a planet!

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Comets
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• A comets orbit is an ellipse shape.
• The comets tail always points away from the sun
  - why?

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MERCURY

• No atmosphere.
• Closest to the sun.
• Daytime temperature 350C.
• Night time temperature -180C.

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Venus

• Thick and dense atmosphere made up of sulphuric
  acid and carbon dioxide.
• Severe greenhouse effect.
• No life.
• No moon.

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EARTH

• Blue planet with clouds.
• Oxygen and water available.
• Inhabited by life forms.

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MARS

• Rocky with red dust on its surface.
• May once have had water
• No life found here so far.

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JUPITER

• The largest planets (all the other planets would
  fit into this one!).
• Atmosphere of liquid hydrogen and helium.

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SATURN

• Rings of small rocks encased in ice.

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URANUS

• Pale green colour.
• Looks as if its lying on its side (it has a
  horizontal axis).

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NEPTUNE

• Similar to Uranus.
• Blue in colour.

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PLUTO

• Not considered to be a planet any longer.
• About 1/5 of the size of the Earth.

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Asteroids

• There is an asteroid belt between Mars and
  Jupiter.
• These are bits of rock of varying sizes.
• These are affected by the gravitational pull of
  the planets, and some have even collided with
  earth!

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Comets

• Made up of a mixture of ice and dust.
• Come from two places Oort cloud (beyond the
  solar system), and the Kuiper belt (beyond
  Neptune).
• They have elliptical orbits.
• Tails always point away from the sun and are
  millions of kilometres long!

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Relative sizes
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Data on the Solar System
Planet Diameter (km) Distance from the Sun (km106) Orbit (Years) Average Temperature (C)
Mercury 4900 58 0.24 350
Venus 12000 108 0.62 450
Earth 12800 150 1.00 15
Mars 6800 228 1.88 -30
Jupiter 143000 780 12.00 -150
Saturn 120000 1430 29.00 -180
Uranus 52000 2800 84.00 -210
Neptune 49000 4500 165.00 -220
Pluto 3000 5900 248.00 -230
You are not expected to learn this information,
but you will need to use the data to draw a
conclusion e.g. ..
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CONCLUSION The average temperature of the
planets decreases with their distance from the
sun. Venus is an exception due to the greenhouse
effect. The change is not constant.
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CONCLUSION The time it takes for planets to
orbit the sun increases with distance. The change
is not constant.
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GRAVITY

• Gravity is the force that exists between two or
  more masses.
• Gravitational force always attracts mass.
• Approximately 1/1,000,000 N exists between you
  and the person next to you (its not strong
  enough to affect us).

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Gravity

• The earth has a lot of mass, so its
  gravitational attraction on our bodies keeps us
  on the ground.

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GRAVITY

• Gravity is the force that keeps the planets in
  orbit around the sun.
• Gravity i the force that keeps the moon (the
  earths natural satellite) in its orbit around
  the earth.
• Gravity is the force that keeps satellites in
  their orbits around the earth.
• Gravity always act on the centre of a mass.

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GRAVITY
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• If its possible to fire a gun quickly enough,
  then the gravitational force that pulls the
  bullet down towards the centre of the earth,
  causes it to orbit around the earth.

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GRAVITY - SUMMARY
Gravity meter
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• A small body keeps in orbit around a larger body
  because of its high mass, and the gravitational
  force between the two bodies.
• The larger the distance between the two bodies,
  the weaker the gravitational force .
• The greater the mass, the greater the gravity.

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DISCOVERING NEW PLANETS
The effect of another planets gravity

• A planets orbit is something that can be
  predicted, but sometimes a planet shows a change
  in its path. Sometimes, the gravitational pull of
  another planet affects its path.
• We have been able to use this sin our search for
  new planets.
• April 24, 2007 a planet similar to earth, 20.5
  light years away, was found, with a larger
  gravity (1.6 more than earth).

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