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.

Origin of the Solar System

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Orbit of the Planets 1

• The four inner planets are rocky.• They are kept in an orbit around

the sun by gravity.

Venus

Earth Mars

Mercury

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Orbit of the Planets 2

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

planet!

Jupiter Saturn

UranusNeptune

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Comets

• A comet’s orbit is an ellipse shape.• The comet’s tail always points away from the sun -

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MERCURYMERCURY

No atmosphere. Closest to the

sun. Daytime

temperature 350°C.

Night time temperature -180°C.

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VenusVenus

Thick and dense atmosphere made up of sulphuric acid and carbon dioxide.

Severe greenhouse effect.

No life. No moon.

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EARTHEARTH

• Blue planet with clouds.

• Oxygen and water available.

• Inhabited by life forms.

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MARSMARS

Rocky with red dust on its surface.

May once have had water

No life found here so far.

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JUPITERJUPITER

The largest planets (all the other planets would fit into this one!).

Atmosphere of liquid hydrogen and helium.

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SATURNSATURN

Rings of small rocks encased in ice.

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URANUSURANUS

Pale green colour.

Looks as if it’s lying on its side (it has a horizontal axis).

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NEPTUNENEPTUNE

Similar to Uranus.

Blue in colour.

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PLUTOPLUTO

Not considered to be a planet any longer.

About 1/5 of the size of the Earth.

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AsteroidsAsteroids 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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CometsComets 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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Data on the Solar System

PlanetDiameter

(km)

Distance from the

Sun (km×106)

Orbit (Years)

Average Temperatu

re (°C)

Mercury 4900 58 0.24 350Venus 12000 108 0.62 450Earth 12800 150 1.00 15Mars 6800 228 1.88 -30

Jupiter 143000 780 12.00 -150Saturn 120000 1430 29.00 -180Uranus 52000 2800 84.00 -210

Neptune 49000 4500 165.00 -220Pluto 3000 5900 248.00 -230

You are not expected to learn You are not expected to learn this information, but you will this information, but you will need to use the data to draw a need to use the data to draw a conclusion e.g. …..conclusion e.g. …..

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Temperature Difference

-300

-200

-100

0

100

200

300

400

500

0 1000 2000 3000 4000 5000 6000 7000

Distance form the Sun (million km)

Ave

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Tem

pera

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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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Amser Orbit

0

50

100

150

200

250

300

0 1000 2000 3000 4000 5000 6000 7000

Pellter o'r Haul (miliwn km)

Am

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Blw

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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 (it’s 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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A

GRAVITY

Gravity is the force that keeps the planets in orbit around the sun.

Gravity i the force that keeps the moon (the earth’s 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

If it’s 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

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.

Gravity meter

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DISCOVERING NEW PLANETS

A planet’s 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).

The effect of another planet’s gravity

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