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© Boardworks Ltd 2003
KS4 Earth and Beyond
© Boardworks Ltd 2003
What we once thought……
I don’t think so!!!
Copernicus
© Boardworks Ltd 2003
The Solar System
What makes up the Solar System?
1. ___________
2. ___________
3. ___________
4. ___________
5. ___________
The Sun
The planets
Moons
Asteroids
Comets
Which of the above are light sources?
Our Sun is a star
© Boardworks Ltd 2003
The Sun
The Sun is the source of energy for life on Earth. Where does this energy come from?
What would happen on Earth if the Sun suddenly disappeared?
The Sun is powered by nuclear fusion reactions. Atomic nuclei are joined together (fused) due to the high pressures inside the Sun.
All plants would die (no photosynthesis), animals would die (no food source), temperatures would drop, there would be no light, it would lead to the end of all life on Earth.
© Boardworks Ltd 2003
The Sun and energy
Scientists were once confused.
If the Sun, they thought, was powered by chemical reactions how has it managed to stay ‘burning’ for millions of years?
There must have been another process producing the energy from the Sun…………. Nuclear Fusion.
What two elements constitute most of the Sun?
How old is the Sun?
Hydrogen and helium
Four and a half billion years
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Nuclear fusion
In nuclear fusion reactions, lighter nuclei are joined together (fused)
……
….to form heavier atomic nuclei.
This releases massive amounts or energy.
In our Sun, a typical star, hydrogen is being fused into
helium, this provides the energy
for life on Earth.
When all the hydrogen is used
up, other elements will be fused
together to make even heavier
elements.
Not all elements are made in this way,
the heaviest elements, some of which are found in your body can only
be made when stars explode.
© Boardworks Ltd 2003
Stellar Evolution 1
Lighter stars like our Sun…..
Nebula collapses due to gravity
Forms a star like our
Sun
Expands to form a Red
Giant
Outer layers of star drift away to leave a dense White Dwarf
Very small nebula form failed stars
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Stars a lot heavier than our Sun…..
Larger nebula collapses due to gravity
Forms a star more massive than our Sun
Expand to form Super-massive
Red Giant
Red Giant collapses violently in supernova
explosionSuper-dense Neutron Star
formed
Stellar Evolution 2
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If the original nebula was massive enough, then when it goes supernova it leaves a star so dense that not even light can escape its gravitational pull.
This is called A Black Hole!
Some scientists believe that there are Black Holes at the centre of galaxies.
Homework Task:
If light can escape a Black Hole, then how do we see it?
Stellar Evolution 3
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The life cycle of a star
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Black Holes
How can you see a Black Hole?
You don’t (AND IT WOULDN’T BE BLACK).
You see the effect it has on nearby matter.
If there is a star nearby, matter from the star will spiral into the Black Hole and as it does so the matter emits X ray radiation which we can detect.
X rays
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Put the following in a flow diagram to show the life cycles of stars. It has been started for you:
Nebula
White dwarf
Neutron star
The Sun
Red Giant
Supernova
Super-massive Red Giant
Star larger than our Sun
smaller nebula
larger nebula
© Boardworks Ltd 2003
The Lifecycle of a star:
Nebula
smaller nebula
larger nebula
White dwarf
The Sun
Red GiantNeutron star
Super-massive Red Giant
Star larger than our Sun
Supernova
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Star questions:
1. What two elements make up most of our Sun?
2. What is a nebula?
3. What process has allowed the Sun to emit light and heat radiation over billions of years?
4. Which is the most dense, a white dwarf or a neutron star?
5. Describe the possible fate of a star similar to our Sun.
Hydrogen and helium
Cloud of gas and dust
Nuclear fusion
Neutron star
Red Giant White Dwarf
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The Sun’s gravity:
1. What force keeps the planets in orbit around the Sun?
2. Which planet shown will feel this force ………..
a) The strongest? b) The weakest?
Not to scale!
Gravity
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Where did the Sun come from?
This causes the “nebula” to collapse
Gravity causes a dust and gas cloud to condense into a smaller volume
As the nebula collapses, temperatures and pressures inside the nebula increase.
When the temperature and pressure are great enough
nuclear fusion starts.
Eventually gravity and the outward pressure of escaping energy is
balanced, and at this stage it is called a star.
Put the sentences in the correct order.
© Boardworks Ltd 2003
Satellites
1. What are the two types of satellite?
2. Give an example of each type?
3. Why are some satellites, like the Hubble Space Telescope shown, put into space?
Natural and artificial
Natural – The Moon
Artificial – Navigation, spy, military, weather, communications
So the Earth’s atmosphere does not get in the way.
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Polar and Geo stationery
Geo stationery
Satellites spin around at the same speed as the Earth, stay above the same location on the Earth’s surface.
Polar
Satellites orbit around the poles, whilst the Earth spins underneath, allowing large areas of Earth to be seen.
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Say if the satellites below have a polar orbit or a geo-stationery orbit:
Polar Geo stationery
Communications
Communications
Spy
Spy
Weather
Weather
Navigation
Navigation
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Comparing orbits
Polar Geo stationery
Height of orbit
Orbital speed
Orbits per day
Orbit position
Example
Use a textbook or other resource to fill in the table below:
lower higher
faster slower
3-4 1
around poles above equator
weather communications
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Can you put these in the correct size order, smallest first?
1. __________
2. __________
3. __________
4. __________
5. __________
Earth
The Sun
The Solar System
The Milky Way
The Universe
Earth
The Sun
The Solar System
The Milky Way
The Universe
© Boardworks Ltd 2003
Match the words and definitions:
A star
A planet
A galaxy
The Universe
The Solar System
There are nine of these in our Solar System. The Earth is one.
Our Sun is one.
Billions of stars together - ours is called the Milky Way.
The Sun, planets, moons, asteroids and comets make up this.
All the galaxies and everything else.
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Identify the different bodies:
A galaxy A star The Universe
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Red shifts
Listen to the noise a plane makes as it passes you……
As the plane approaches it sounds higher pitched……….
…then when it is moving away from you, it sounds
lower pitched.
This is due to the Doppler effect, the same thing happens with light. Approaching objects have the wavelength of the light they emit shortened (red-shifted), receding objects have the wavelength of light they emit increased (blue-shifted).
© Boardworks Ltd 2003
Hubble
Hubble was a famous scientist who examined the light from nearby galaxies. He noticed two things:
1. That most of the galaxies’ light was shifted towards the red end of the spectrum;
2. The further away a galaxy was, the more its light was red-shifted.
From these observations he concluded:
1. That most galaxies were moving away from our own;
2. The further away a galaxy was, the faster it was moving away from us;
3. And therefore he concluded that the universe is expanding.
© Boardworks Ltd 2003
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Fate of the Universe Research
What is the possible origin and fate of the Universe?
Using a textbook, CD-Rom or the internet try to find two different theories about the origins and fate of the Universe.
Hints:
Cosmic microwave background radiation
The Big Bang
The Big Crunch
Hubble
Expanding Universe
Red-shifts
Open UniverseClosed Universe
Steady State Theory
Density
© Boardworks Ltd 2003
The Big Bang Theory
This theory states that the Universe is expanding due to a large ‘explosion’ (big bang) billions of years ago.
Evidence?
1. The Cosmic Microwave Background Radiation (CMB), which is thought to be an ‘echo’ of the initial explosion.
2. Hubble’s observations about red-shifted light.
There are different fates for the Universe with this theory:
1. The Universe expands for ever if there is not enough gravity to halt its expansion – OPEN UNIVERSE.
2. The Universe will eventually start to contract due to gravity – CLOSED UNIVERSE.
© Boardworks Ltd 2003
Steady State Theory
This theory states that the Universe is expanding and as it expands matter is created to maintain a uniform universal density of matter.
Evidence?
Hubble’s observations about red-shifted light.
However:
This theory has become less popular since the discovery of Cosmic Microwave Background Radiation (CMB).
© Boardworks Ltd 2003
Are we alone?
If there are aliens they would have
contacted us by now.
The Universe is so big, even if there are aliens,
they are too far away for us to ever meet them.
Life exists on Earth and only on Earth.
If there are aliens they will probably not look
like you or me.
For life to exist there must be liquid water, on a planet or moon
and oxygen.
You have 10 minutes!!!
We are all aliens, life began on comets and asteroids
and transferred to the Earth when they collided with it.
In pairs discuss the points below and then share you ideas with the rest of the group.
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What is the name of the furthest planet from the Sun?
A. Earth
B. Jupiter
C. Pluto
D. Venus
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Why is Venus hotter than Mercury?
A. It is closer to the Sun
B. It is further away from the Sun
C. Acid Rain
D. The Greenhouse Effect
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What object from the Solar System is shown?
A. Comet
B. Planet
C. Asteroid
D. Moon
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What elements is the Sun mostly made from?
A. Iron and nickel
B. Strontium
C. Hydrogen and helium
D. Helium and neon
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Which of these planets has two moons called ‘Fear’ and ‘Dread’?
A. Earth
B. Venus
C. Saturn
D. Mars