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Deans Community High School
Physics
Dynamics and Space
1.3 Space
Name_______________ Class ____
Content Level 4
SCN 4-06a
By researching developments used to observe or explore space, I can illustrate how
our knowledge of the universe has evolved over time.
SCN 4-16a
I have carried out research into novel materials and can begin to explain the
scientific basis of their properties and discuss the possible impacts they may have
on society.
SCN 4-20a
I have researched new developments in science and can explain how their current
or future applications might impact on modern life.
SCN 4-20b
Having selected scientific themes of topical interest, I can critically analyse the
issues, and use relevant information to develop an informed argument.
Content National 4
Satellites
o
The range of heights and functions of satellites in orbit around the earth, including
geostationary and natural satellites.
o
The dependence of period of orbit on height.
o
The use of parabolic reflectors to send and receive signals.
o
Use of the relationship between distance, speed and time applied to satellite
communication.
o
Range of applications of satellite including telecommunications; weather monitoring; the
use of satellites in environmental monitoring.
o
The use of satellites in developing our understanding of the global impact of mankind’s
actions.
Cosmology
o
Description of planet, moon, star, solar systems, exo-planet, galaxy and universe.
o
Scale of the solar system and universe measured in light years.
o
Space exploration and its impact on our understanding of the universe and planet Earth.
o
Conditions required for an exo-planet to sustain life.
Dynamics and Space 5
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Content Statements
Content National 5
Space exploration
o
Evidence to support current understanding of the universe from telescopes and space
exploration.
o
Impact of space exploration on our understanding of planet Earth, including use of satellites.
o
The potential benefits of space exploration including associated technologies and the impact
on everyday life.
o
Risks and benefits associated with space exploration, including challenges of re-entry to a
planet’s atmosphere.
Cosmology
o
Use of the term ‘light year’ and conversion between light years and metres.
o
Observable universe — description, origin and age of universe.
o
The use of different parts of the electromagnetic spectrum in obtaining information about
astronomical objects.
o
Identification of continuous and line spectra.
o
Use of spectral data for known elements, to identify the elements present in stars.
.
Dynamics and Space 5
4
Content statements
Learning Outcomes - Cosmology
At National 4 level, by the end of this section you should be able to:
Cosmology
 1. List the risks and benefits associated with space exploration and
challenges of re-entry to a planet’s atmosphere.
 2. Describe the use of thermal protection systems to protect spacecraft
on re-entry.
 3. Provide descriptions of the following; planet, moon, star, solar systems,
exo-planet, galaxy and universe.
 4. State the scale of the solar system and universe measured in light
years.
 5. Describe the impact of space exploration on our understanding of the
universe and planet Earth.

Research developments used to observe or explore space and
illustrate how our knowledge of the universe has evolved over time.
 6. Describe the conditions required for an exoplanet to sustain life.
Additionally, at National 5 level:
 7. Describe the term ‘light year’ and use the conversion between light
years and meters.
 8. Provide a description of the observable universe and know the origin and
age of the universe.
 9. Describe the use of different parts of the electromagnetic spectrum in
obtaining information about astronomical objects.
10. Identify continuous and line spectra.
 11. Identify elements present in stars from the use of spectral data for
known elements.
Dynamics and Space 4/5
5
Learning outcomes- Cosmology
Planets and Moons
Planet and moons do not make their own light, they reflect light from the sun.
 planets orbit the Sun.
 planets are roughly spherical/ball shaped.
 moons come in many sizes, but always orbit a planet.
 planets and moons produce their own gravitational field
Stars – what are they?
Stars produce visible light
(plus every other type of
electromagnetic radiation)
by nuclear fusion reactions.
 they are large, massive,
balls of gas,
 mostly made of hydrogen
and helium.
s
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Cosmology
Our Solar System
Our solar system consists of our star (“Sol”, the Sun) plus the 8 planets, lots of
moons, comets and asteriods.
 In order from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn,
Uranus, Neptune.
 Mercury and Venus have no moons. Earth has one. The others have many
moons.
 The four “inner planets” are rocky and dense. Planets nearest the sun are
warmer.
 The four “outer planets” are gas giants, with cooler atmospheres.
 All these planets have atmospheres except for Mercury.
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Cosmology
Definition of a light year
 It is the distance travelled by light in one whole year.
 1 light-year is usually written as 1ly for short.
 The nearest star to the Sun is 4.2ly away (Proxima Centauri).
Light year Equivalent in Metres
Calculate the distance in metres, that light travels in one year.
The speed of light in vacuum is 300 000 000m/s..
Distance
= speed x time
= 300,000,000 x 365 x 24 x 60 x 60
= 9,460,800,000,000,000
= 9.46 x 1015m
Distances in Space
Time for light to travel from the sun to Earth – 8 minutes
Time for light to travel to Proxima Centuri - 4.22 years
(nearest star to Earth other than the sun)
Time for light to travel to the edge of the Galaxy – 100,000 years
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Cosmology
Our Milky Way and other Galaxies
This graphic shows our galaxy, the Milky Way.
It is roughly 100,000 ly across.
 Our galaxy has a spiral shape with a bar
at the center.
 Others shapes like rugby balls also
exist.
 Galaxies typically contain about 100
billion stars each.
Galaxies are held together by their own
gravity
Exoplanets and Life Beyond Our Solar System
An exo-planet is a planet orbiting around another star (not our Sun).
 To support life-as-we-know-it, an exoplanet must
◦ be not too hot or too cold
◦ have liquid water
◦ have air with oxygen in it
◦ be rocky (not a gas giant)
The Age of the Universe
Cosmologists estimate the age of the universe to be around 14 billion years,
since the “Big Bang”.
The idea of the Big Bang is that there was a hypothetical violent explosion that
created the universe. The theory states that all the matter and energy of the
universe was once an unimaginably dense mass and that the universe has been
expanding from the explosion of this mass ever since.
Evidence for the Big Bang is that we can see that the universe is still expanding
as stars get further apart.
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Cosmology
The Observable Universe
Simply, this is the part of the universe that we can see now, from Earth.
How do we Explore Space?
There are 3 main ways to explore space:
1. By observing. This is astronomy.
2. Sending humans on rockets. We have visited near Earth orbit and the
Moon only.
3. Sending robotic probes. Mercury, Venus, Mars, Jupiter, Saturn, Uranus,
Neptune have all been visited by robotic probes.
Re-entry to atmosphere
When a spacecraft re-enters the atmosphere
it slows down due to friction with the
atmosphere.
The friction also causes it to heat up.
This is potentially a very dangerous part of a space mission.
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Cosmology
Learning Outcomes - Satellites
Satellites
 1. Describe the range of heights and functions of satellites in orbit around
the earth, including geostationary and natural satellites.
 2. Describe the dependence of period of orbit on height.
 3. Describe the use of parabolic reflectors to send and receive signals.
 4. Carry out calculations involving the relationship between distance, speed
and time applied to satellite communication.
 5. Describe the range of applications of satellites including
telecommunications; weather monitoring; the use of satellites in
environmental monitoring.
 6. Describe the use of satellites in developing our understanding of the
global impact of mankind’s actions.
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Learning Outcomes -Satellites
Newton’s Thought Experiment
Any projectile follows a curved path.
If you fire a projectile with greater
velocity it will travel further.
Newton’s Thought Experiment
Newton thought that if it were possible
to fire an object from a very large
cannon with enough velocity it would
fall towards Earth at the same rate as
the Earth falls away.
The object will orbit Earth.
This is how satellites work.
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Satellites
Satellites
A satellite is an object which orbits a planet.
The Moon is an natural satellite.
Uses of Satellites
Communications – used to transmit radio and tv signals as well as mobile phone
signals across the world.
Weather forecasting – Used to track the progress of weather fronts round the
globe. Can predict where hurricanes may make landfall.
GPS/ Navigation – Used to locate the position of cars, boats and planes. This can
be useful in locating good fishing areas. A satellite navigation system receives
radio signals transmitted by satellites in orbit around the Earth. The satellite
navigation system finds it location by calculating the distance the transmitted
signals travel.
Security/Spying – Used to watch for potential hazardous situations arising.
Monitoring changes – Ice Floes/COs/ Ozone Layer - used to monitor the
changes over time caused by the changes in the environment.
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Satellites
Period of a Satellite
The time it takes a satellite to make one complete orbit of Earth.
The higher the satellite orbit the longer it takes for one complete orbit
Geostationary Satellite
A satellite which appears to stay in the same place, relative to Earth, all the
time.
Period = 24hours
Satellite Transmitter
Signals sent out from central
transmitter hit the dish and bounce back
in a parallel beam so that they can be
aimed at the satellite.
Satellite Receiver
Weak signals are collected over a
large area, then reflected to a
central point. This makes the
received signal stronger.
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Satellites
Intercontinental Communication Using Satellites
A
B
Signals are sent from ground station A to the satellite.
The satellite receives, then retransmits the signal.
Ground station B receives the station.
Signals can travel in either direction.
If the satellite is geostationary the communication link is available 24 hours
a day.
If the satellite is in a lower orbit it will be visible less often because it is
not always over the same part of the Earth the whole time.
Example 50
In addition to the speed of the signals, what other quantity must be known to
calculate distance? Time
Example 51
A satellite is at a height of 150km. If the signal travels at 300,000,000m/s, how
long will it take for the signal to travel from one ground station to the other?
Total distance travelled = 2 x 150,000 = 300,000 m
Time = distance/speed = 300,000/300,000,000 = 0.001s
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Satellites
Freefall and Weightlessness
Weight is a force which pulls us down towards the ground – we are aware of our
weight because of the ground pushing back on our feet.
If the ground falls away from you at the same rate as you fall towards the
ground you experience weightlessness.
If you are a long way away from a planet the gravitational force of the planet
would be so small that you feel weightless.
In the Space Station astronauts are weightless because they fall at the same
rate as the Space Station falls round Earth.
Example 52
On Earth an astronaut has a weight of 550N.
What is her weight in the Space Station?
0N
Example 53
On Earth an astronaut has a weight of 550N. What
is her mass in the Space Station?
W = mg => m = 550/10 = 55kg
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Newton’s Laws
Learning Outcomes - Space Exploration
Space Exploration
 1. List evidence that supports our current understanding of the universe
from telescopes and space exploration.
 2. Describe the impact of space exploration on our understanding of planet
Earth, including the use of satellites.
 3. Describe the potential benefits of space exploration including
associated technologies and the impact on everyday life.
 4. Describe the risks and benefits associated with space exploration,
including challenges of re-entry to a planet’s atmosphere.
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Learning Outcomes - Space Exploration
Risks and Benefits of Space Exploration
Space Exploration has risks – so far 18 people have lost their lives during
spaceflight missions. A further 11 people have died during training.
In comparison over 200 people were killed in road traffic accidents in Scotland
in 2010.
Although Space Exploration is dangerous astronauts go through extensive
training to help them deal with whatever situations they find themselves in.
The benefits to society include
Increased aviation safety
Knowledge about the moon
Increased knowledge about how Earth was formed
New materials
Novel uses of existing materials
New technology
An opportunity to try experiments in zero gravity
Re-entry to atmosphere
One of the most dangerous aspects of space flight is getting back to Earth.
When a spacecraft comes back into the atmosphere it slows down due to
friction between the spacecraft and the air particles in the atmosphere.
The work done by friction is converted to heat energy, which causes the
spacecraft to heat up. This can be as much as 1300⁰C.
To protect the astronauts special materials are used which prevent heat
transfer into the spacecraft.
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Space Exploration
/kg⁰)
Air
Terminal Velocity
resistance
When a parachutist (or other object) falls they
accelerate because gravity pulls them downwards.
As they get faster the air resistance increases
until the forces are balanced.
When the forces are balanced they travel at
Air Resistance
Weight
constant speed. This is called their terminal
velocity.
When a parachute is opened there is a greater air
resistance, so the person slows down.
Eventually the force acting on the person are
balanced.
When the two forces are balanced they again travel
at constant speed. This is their new terminal
velocity.
Speed
Weight
0
Dynamics and Space 5
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Space Exploration
The Electromagnetic Spectrum in Astronomy
All parts of the electromagnetic spectrum can be used in astronomy.
Remember, starting with the lowest frequency, the components of the spectrum
are:
Radio, Microwaves, Infrared, ROYGBIV, Ultraviolet, X-Rays, Gamma.
 As the frequency increases, the energy of the radiation also increases.
This means that gamma ray telescopes (for example) pick up more astronomically
violent events (like supernova explosions).
 Because the Earth's atmosphere protects us from dangerous UV, X-ray
and gamma radiation, we have to observe these frequencies from Earth
orbit.
All electromagnetic waves (in a vacuum) travel at 3 x 108 m/s (speed of light)
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Space Exploration
White light
When white light is passed through a prism it forms a spectral pattern
R –
Red
O - Orange
White
light
Y -
Yellow
G -
Green
B –
Blue
I - Indigo
V -
Violet
When white light is passed through a prism it forms a spectral pattern
Telescopes
Objective
lens
Eyepiece Lens
Light tight tube
Objective Lens - Large to allow lots of light to enter the tube.
Eyepiece Lens – allows the observer to focus on the image produced by the
Objective Lens
Light tight tube – keeps out light from surroundings.
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Space Exploration
Radio Telescopes
Radio telescopes tune into radio
waves from space. Signals detected
are turned into images using a
computer.
To produce a sharper, more detailed,
Parkes Observatory, NSW, Australia
image a number of smaller telescopes
can be joined together to make a
‘Very Large Array’ (VLA).
Radio astronomy has led to the
discovery of new types of star such
as Quasars in the 1950’s and Pulsars
in 1967.
Very Large Array, New Mexico, USA
Radiations from Space
A line spectrum consists of a complete (continuous) spectrum with certain
colours missing which appear as black line in the spectrum.
Every element produces a unique line spectrum. Studying line spectra allows the
elements present in a light source (e.g. a star) to be identified (this can allow
the type, distance, age or speed of a star to be identified)
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Cosmology
Radiation from Space
Example 54
Some spectral lines of radiation from a distant star are shown below.
The spectral lines of a number of elements are also shown.
Use the spectral lines of the elements shown to identify which of these
elements are present in the distant star.
Cadnium and Mercury,
Triple group at right are missing for Calcium
Second double group for Krypton are missing – just!
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Cosmology
Types of Radiation from Space
The Earth’s atmosphere and magnetic field protect us from most harmful
radiation from space.

The Sun, other stars, supernovae explosions are all producing high energy
radiation.

Gamma rays are the most energetic, high frequency parts of the
electromagnetic spectrum

Cosmic rays are fast moving particles, mostly protons and electrons, but
some antimatter too. Cosmic rays are NOT part of the electromagnetic
spectrum

Neutrinos are particles having no electrical charge and almost no mass.
They are produced in vast numbers by the nuclear fusion reactions in the
Sun’s core. They mostly pass straight through our entire planet (and us).
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Cosmology