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Space
Perspectives of Earth
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Summer solstice (June 21) – the
longest period of daylight; the start
of summer
Winter solstice (December 21) –
the shortest period of daylight; the
start of winter
Solstices are reversed in the
southern hemisphere
Equinox: day and night are of equal
length (March 21 and September 22)
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The Celts created
Stonehenge to mark
winter and summer
solstices.
African cultures
made large stone
pillars into patterns
to predict the timing
of the solstices
Useful to know when
to plant and harvest
crops
Stonehenge is angled such that on the
equinoxes and the solstices, the sun rising
over the horizon appears to be perfectly
placed between gaps in the megaliths.
Orbits
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Ecliptic: path of the sun through the
sky during the year, crosses the
celestial equator at the vernal
(spring) and autumn (fall)
equinoxes.
The Sun’s northerly position on the
ecliplipse marks summer solstice.
Its most southerly position marks
winter solstice.
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Inuit: the width of a mitt held at arm’s
length to gauge the height of the sun
above the horizon. When the sun rose to
the height of one mitt width, it meant the
seal pups would be born in two lunar
cycles.
The sun played a role in mythology of
ancient cultures (North American natives,
Aztecs, Chinese, Inuit, Greeks, Norse,
Japanese).
Ancients used rock structures and
buildings to align with stars (2700 BC
pyramids built in Egypt, Stonehenge).
Models of Planetary Motion
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2000 years ago Aristotle developed
the geocentric model (Earthcentered model)
Earth was at the center with
concentric spheres encircling it
The distant stars were fixed on the
outermost or celestial sphere
Predicted the phases of the moon,
but little else
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Ptolemy added
epicycles, smaller
spheres attached
to the main
spheres. This
helped make
predictions more
accurate.
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In 1530 Copernicus
developed the
Heliocentric model: the
sun at the center and
planets revolved in orbits
around it.
In the 1600s, Galileo
used a telescope to
provide observations to
back up this model
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Johannes Kepler: orbits of
the planets were elliptical,
figured out the shape and
scaled the entire solar
system from the same
observations.
Sir Isaac Newton explained
elliptical orbits by proving
that there is a gravitational
attractive force between all
objects that pulls them
together in an orbit.
Ancestral Contributions
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stars make unchanging patterns in
the sky which looked like named
objects
use the movement of stars to mark
months and seasons, led to the
development of the calendar
the Sun, Moon and Planets rise and
set at different rates from the stars
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7000 years ago, sundials were used to
measure the passage of time
Egyptians invented a merkhet to chart
astronomical positions and to predict the
movement of stars.
Egyptians designed a quadrant to
measure a star’s height above the
horizon.
Arabian astronomers used an astrolabe to
make accurate charts of star position.
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Levi ben Gurson invented the cross staff
to measure angle between the moon and
a star.
Hans Lippershey invented the telescope in
the late 16th century.
Galileo Galilei improved the telescope and
it revolutionised astronomy. He concluded
that the stars are much farther away than
the planets.
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Kepler described the elliptical shape of
the planet’s orbits.
Isaac Newton: law of universal gravitation
an explanation for the planets’ elliptical
orbits.
The introduction of mathematical
approaches (Kepler and Newton) into
describing the motion of objects within
the universe allowed astronomers to
make accurate predictions about the
motion of objects in the universe.
Distribution of Matter in Space
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Astronomical Units (AU): used for
measuring “local” distances, inside our
solar system. One AU is equal to the
average distance from the center of the
earth to the center of the sun (149 599
000 km). Astronomers use this when
describing the positions of the planets
relative to the sun.
Light-year: equals the distance light
travels in one year. Used for measures
beyond our solar system.
Star Classification and Life Cycle
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Star: a hot glowing ball of gas (mainly
hydrogen) that gives off light energy. The
number of stars in the universe is in the
billions.
Stars vary greatly in characteristics
The color of a star depends on its
temperature. A very hot star looks blue. A
very cool star looks red.
Hertzsprung and Russell: compared the
surface temperature with brightness
(luminosity). Star distribution in their
diagram is not random – there are several
specific groupings.
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Nebulae (Prostar): area of space where huge
accumulations of gas and dust collect and where
stars are formed.
Each nebulae is composed of 75% hydrogen and
23% helium. The other 2% is oxygen, nitrogen,
carbon and silicate dust.
Some of this interstellar matter came from
exploding stars. Depending on the mass of the
star formed from a particular nebula, the star will
be sun-like (in terms of mass) or massive.
Both types of stars spend most of their lives in
this main sequence converting hydrogen to
helium in their cores.
Paths of Star Development
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Nebula  sun-like stars (main
sequence)  red giant  white
dwarf  black dwarf
Nebula  massive stars (main
sequence)  red supergiant 
supernova  black hole
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Red Giant/Red Supergiant: when a sunlike star increases in size and becomes
very bright.
White Dwarf: when a sun-like star
collapses: white dwarfs are very hot but
very faint.
Black Dwarf: when a white dwarf fades.
Supernova: an enormous explosion that
marks the death of a massive star.
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Black Hole: a dense
remnant of a super
nova; an object
around which
gravity is so
intense even light
cannot escape.
Neutron Star: If
the explosion does
not destroy a star,
the core is left as a
neutron star.
Black Hole
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Constellations: groupings of stars we see
as patterns in the night sky.
Asterism: distinctive star grouping that is
not one of the 88 constellations (e.g. Big
Dipper which is part of the Ursa major
constellation).
Galaxy: a grouping of billions of stars, gas
and dust held together by gravity.
Shapes of Galaxies
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Spiral: long curved arms radiating
out from a bright central core
Elliptical: football or egg-shaped
which is made up of old stars
Irregular: no shape and smaller
than the other 2; made up of young
and old stars
Bodies Making Up Solar Systems
Protoplanet hypothesis (explains
the birth of solar systems):
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A cloud of gas and dust in space
begins swirling
Most of the material (more than
90%) accumulates in the centre,
forming the sun
The remaining material accumulates
in smaller clumps circling the centre.
These form the planets.
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Solar Wind: streams of electrically
charged particles discharged by the sun in
every direction.
Solar wind is the result of solar flares,
explosions that force particles from the
sun into space.
Some of these particles spiral down the
Earth’s magnetic field and enter the
atmosphere to produce the Northern and
Southern lights (Aurora Borealis and
Aurora Australis).
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Sun: the centre of our solar system, 110
times wider than the Earth.
The solar system can be divided into two
planetary groups: the Earth like
(terrestrial) planets and the outer or
Jovian planets.
Terrestrial planets: smaller, rockier, closer
to the Sun.
Jovian planets: large and gaseous, located
greater distances from the Sun with small
densities, rings, and many satellites.
Size of space objects
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Milky Way (galaxy) > Solar System >
Planets (Jovian > Terrestrial) > Moons
Asteroids: small, rocky or metallic,
range in size from a few meters to
several hundred kilometers across and
are found between the orbits of Mars
and Jupiter.
Comets: “dirty snowballs” made up of
dust and ice, have bright center and a
long faint tail that always points away
from the Sun. Ex. Halley’s comet.
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Meteoroids: small pieces of rock
flying through space with no
particular path, are as small as a
grain of sand or as large as a car.
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Meteor: (shooting stars) When a
meteoroid gets pulled into the
atmosphere by Earth’s gravity, the heat
of atmospheric friction causes it to give
off light.
Meteorite: a meteor that hits the Earth’s
surface
Eclipses
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A solar eclipse occurs when the moon
passes between the Sun and Earth
casting a shadow on Earth.
A lunar eclipse occurs when Earth passes
between the Sun and Moon, casting its
shadow over the Moon.
Determining Position and Motion in
Space
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To locate the position of an object in
space two questions must be answered,
“How high in the sky is it?” and “In which
direction?”
This problem can be solved with two
measurements. The first is the compass
direction called azimuth, with north as 0.
The second is how high in the sky and is
called altitude, which ranges from 0 to 90
degrees. Zenith refers to highest point
directly overhead.
Spectrometry or Spectrometers
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Spectroscopes tell us how fast a
celestial body, such as a star, is moving
toward or away from us using the
Doppler Effect.
 Light refracted from stars creates a
‘fingerprint’ for each star. Astronomers
compare the spectra of a star with
known spectra of elements (H, He, Na,
Ca) to determine a star’s composition.
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The Doppler Effect occurs when
sound waves are compressed in
front of a vehicle as it speeds along.
This results in a shorter wavelength
and a higher pitch.
Behind the vehicle sound waves
stretch out, creating a longer
wavelength and lower pitch.
It can also be used in radar guns to
show how fast a vehicle is moving.
The Doppler effect can apply to lightemitting objects such as stars.
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When a star is approaching you, its
wavelengths of light become compressed.
As a result, the dark lines in the star’s
spectrum shift toward the shorterwavelength end of the spectrum – the blue
end.
If a star is moving away from you, its
spectral lines will be red shifted (moving
toward the longer-wavelength part – red
end- of the spectrum).
The amount of shift showing up in
observations indicates the speed at which
the star is approaching or receding.
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Another method to determine position and
movement of celestial bodies (such as the
Sun, Moon and planets) involves using the
stars as the frame of reference instead
of the Earth.
Note which bright stars are around Venus
and take note of the location of Venus
relative to these bright stars. The next
night, repeat the procedure. Where is
Venus in relation to the bright stars? If you
continue to take note of the location of
Venus in relation to the same bright stars,
you will find that it is moving.
Space Exploration
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Challenges
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go fast enough to achieve orbit around
Earth or break free of Earth’s gravity
and travel to other planets
keep equipment operating in extreme
environment of space
to transport people out and back safely
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Environmental Hazards:
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space is a vacuum, with no air or H2O
damaging effects of cosmic rays and
solar radiation
risk of being hit by debris or
meteoroids
no air pressure
massive temperature variations
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Psychological Challenges
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long trips in a confined living space
Body and Microgravity
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microgravity is a condition in which the
gravitational forces that act on mass
are extremely reduced
bones expand
 loss of muscle mass and tone
 loss of bone mass and density
 loss of body mass
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heart does not have to pump as hard to
circulate blood which decreases red
blood cell production
muscles become weaker as less
walking and lifting occurs: loss of
calcium, electrolytes and plasma with
excretion of body fluids
Life Support in Space
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Space Suit
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self-contained living system of air, water, a
heating system, a cooling system … a portable
toilet
flexible enough to allow fine motor control
Oxygen
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electrolysis uses electricity to split water
molecules into their component elements H2
and O2 -> hydrogen is vented into space
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Water
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water will need to be recycled over and
over because they can only bring a
limited supply
technology to filter, purify and recycle
the same water (this technology is
used on Earth to provide
environmentally safe sewage treatment
for houses)
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Life Support System functions
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recycle wastewater to produce drinking
water and use recycled water to
produce oxygen
remove carbon dioxide from air
filter micro-organisms and dust from
air
keep air pressure, temperature and
humidity stable
Space Transport
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To get an object into space, scientists
needed to determine at what speed an
object could overcome the force of gravity
= 28 000 km/h
A rocket is a tube that contains combustible
material on one end. The other end is the
payload or the device/material that the
rocket carries.
Robert Goddard was the first scientist to
successfully launch a liquid fuel rocket in
1926.
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He discovered that if a rocket had more
then one stage, it would fly higher and
faster. A stage is a section of a rocket
that drops off once the fuel is used up.
In 1942 Werner von Braun developed the
first ballistic missile (V-R rocket) during
World War II – a bomb powered by a
rocket engine. It had the ability to hit a
target 200 km away from the launch site.
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1957 – Soviet union
launched the first
artificial satellite
called Sputnik
1960’s – Werner von
Braun’s team
developed the rockets
that took the first U.S.
astronauts into space
1962 – Canada
became the third
nation to launch its
satellite – Alouette 1
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Sputnik (the size of a
basketball) and
Alouette I
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Rocketry relies on a fundamental law of
physics: for every action there is an equal
and opposite reaction.
An opening in the chamber allows gas to
be released producing thrust (push) and
causing the rocket to be propelled in the
opposite direction.
The speed at which the exhaust leaves
the rocket is called exhaust velocity.
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There are three basic parts to a rocket: the
machinery, the fuel and the payload.
The machinery is everything from the
rocket itself to the engines, storage, tanks
and fins.
Computers in the air and on the ground
work together to control the flight of
spacecraft. They calculate orbits, keep
track of other satellites (and pieces of
space junk), collect, store, and analyze
data, and to execute orbital maneuvers of
the satellites.
Gravitational Assist
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A method of acceleration which
enables a spacecraft to gain extra
speed by using the gravity of a
planet.
The planet’s gravity attracts the
craft, causing it to speed up and
change direction. The craft
“slingshots” away from the planet at
a higher or lower speed than it had
before its encounter with the planet.
Satellites
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Artificial Satellites
objects built and sent into Earth’s orbit by
humans
Natural Satellites
small body orbiting a larger body (i.e.,
moon orbiting a planet)
Functions of Satellites
help us communicate, observe and forecast
weather, predict storms and even find our
location on the planet as well as allow for
satellite TV, long distance phone calls and
GPS for drivers
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weather satellites stay in one position
above Earth (geosynchronous)
geosynchronous orbit: moves at the same
rate as the Earth spins and therefore the
same area is observed at all times
result is a 24 hour per day monitoring of
weather conditions
observation satellites :take photographs
and monitor weather
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LANDSAT and
RADARSAT follow
ships at sea,
monitor soil
quality, track forest
fires, report on
environmental
change and search
for natural
resources (not
geosynchronous)
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REMOTE SENSING
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imaging devices in a satellite make
observations of Earth’s surface and
send this information back to Earth
(information can be in the form of
photographs or data from energy
waves)
provides information on the condition
of the environment on Earth, natural
resources and effects of urbanization
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Global Positioning System (GPS)
 24 GPS satellites are in orbit around
Earth, which means there are at least 3
above any given location in the world at
any time
 radio signals from satellites are picked
up by a hand-held receivers
 signals are translated by a computer in
the receiver, which shows on a digital
displace the operator’s position in
relation to the satellites
Optical Telescopes
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gather and focus light from stars so that
we can see it
the larger the area of the lenses or
mirrors in a telescope, the greater the
ability of the telescope to see distant
objects
the objective lense is the larger of the two
lenses at the front of the tube
the eyepiece is the lense you look through
the image is distorted because of
atmospheric interference
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Refracting telescope
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uses 2 lenses to gather and focus
starlight
limited size as any diameter over 1
metre will cause the glass to warp
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Reflecting telescope
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uses mirrors to gather and focus
starlight
newer models use segmented mirrors
(segments to form one large mirror)
because they have enormous lightgathering ability and resolving power
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Combination telescope
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Interferometry: using telescopes in
combination
detect objects in space more clearly
and at greater distances
Hubble Space Telescope
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reflecting telescope, orbiting 600
km above Earth, uses a series of
mirrors to focus light from
extremely distance objects
Earth-based telescopes are limited in
their viewing ability by interference
from moisture, clouds, air pollution
and light pollution.
Adaptive Optics
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stars twinkle because the motion of the
Earth’s atmosphere refracts light
randomly
due to this twinkling or blurring effect,
computers have been attached to
telescopes in order to sense when the
Earth’s atmosphere moves; the
computers communicate with devices
under the objective mirror so that the
mirror is distorted to cancel out this effect
Role of Telescopes
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Electromagnetic energy:
energy traveling at the speed of
light but having different
wavelengths (measurement of
distance from one point on a wave
to the same point on next wave)
and frequencies (equals the number
of waves that pass a single point in
1 second) than those of light
Radio telescopes
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study radio waves emitted by objects in
space  millions of times longer than
light waves
advantages over optical telescopes
 not affected by weather and can be
detected day and night
 not distorted by clouds, pollution or
atmosphere
interferometry is used to enhance the
performance, measurement of position,
accuracy and detail of the radio images
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because radio waves cannot be
seen, computers are attached to the
radio telescopes to produce colorcoded images that correspond to
the strength or intensity of the
signal (from low intensity to high
intensity, the colors are blue, green,
yellow, red, white)
Very long baseline interferometry
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When 2 or more radio telescopes are
connected, without wires, to produce
images 100 times as detailed as the
largest optical telescopes.
Each telescope’s signal is recorded with
timing marks; signals are transferred to
computer disks, loaded onto a central
computer, and combined to form one
image.
Space Probes
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unmanned satellites or remote-controlled
landers that put equipment on or close to
planets too difficult or dangerous to send
humans to.
Purposes: sample soil, examine rings and
moons, study atmospheric composition,
perform geological tests, study how
planets form in the solar system and how
the characteristics of other planets
compare with Earth’s.
Global Positioning Technology
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Triangulation based
on the geometry of a
triangle. Measuring the
angle between the
baseline and the target
object allows you to
determine the distance
to that object.
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Parallax
apparent shift in position of a nearby
object when the object is viewed from 2
different places (e.g. passenger versus
driver view of the speedometer)
a star’s parallax is used to determine
what angles to use when they triangulate
the star’s distance from Earth
we use the diameter of Earth’s orbit as a
baseline which means measurements are
taken 6 months apart
Remote Sensing
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the science of taking measurements of Earth (and
other planets) from space
applications are:
satellite images can be computer processed to
show healthy versus unhealthy vegetation
clear-cut and burned forests can be mapped to
show the rates of their degradation
water pollution can be imaged
erosion can be tracked
land use in cities can be observed
tracking weather patterns
GPS Satellites
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Each GPS satellite transmits data that indicates
its location and the current time.
All GPS satellites synchronize operations so that
these repeating signals are transmitted at the
same instant.
The signals, moving at the speed of light, arrive
at a GPS receiver at slightly different times
because some satellites are farther away than
others.
The distance to the GPS satellites can be
determined by estimating the amount of time it
takes for their signals to reach the receiver.
When the receiver estimates the distance to at
least four GPS satellites, it can calculate its
position in three dimensions.
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The unit then calculates your location on
Earth, using the triangulation method that
is programmed into the system. Most
units can pinpoint your location to within
about 30m.
Today, GPS receivers are used by fishers
to mark good fishing spots, by pilots to
track their airplane’s position, and by
paleontologists to mark dinosaur sites.
Risks and Dangers of Exploration
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destructive effects of solar radiation
on life and equipment
danger of possible collisions with
comets and asteroids
loss of life
immense economic loss
loss of time spent on work
2003 Challenger destroyed due to
faulty ceramic tiles
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1967 Apollo I crew died due to fire on
board the spacecraft
1986 Challenger exploded shortly after
takeoff
loss of Mars probes (Russian and American)
2001 – only 1/3 of the 2700 satellites are
actually working; the rest are “space junk”
early 2001 – Russian space station burned
up on re-entry into Earth’s atmosphere
cosmic radiation causes extreme damage to
human cells
Space Junk
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Pieces of debris that have fallen off
rockets, satellites, space shuttles and
space stations and remain floating in
space
threat to orbiting space craft satellites,
etc as the impact could cause severe
damage to their structural integrity
threat to Earth as junk can re-enter
Earth’s atmosphere and destroy lives and
geographical damage
Canadian Contributions
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Magnetic observatory
1839 Sir Edward Sabine established the
first magnetic observatory and discovered
the aurora borealis and was related to
sunspot activity
Alouette 1
1962 Canada launched Alouette 1, a
satellite for non-military use
Anik 1 Satellite
1972 Anik 1 gave the entire country
telecommunications coverage for the first
time
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Satellite TV
1973 Canada is the first country in the
world to use satellites to broadcast
television
Canadarm 1
Canadarm 1, a robotic arm manipulated
by remote control, debuted on space
shuttle Columbia in 1981. It launched and
retrieved satellites/ fixed optical
apparatus on Hubble Space Telescope/
put together modules of International
Space Station
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Canadarm 2
(also called Canadian Space Station
remote manipulator system SSRMS)
2001 – bigger, stronger and
smarter than its predecessor.
Attached to the end of the arm is
the Canada Hand (also called the
special purpose dexterous
manipulator SPDM)
Issues in Space
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Who owns space?
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property of the first nation to land?
eco-tourists who observe or pioneers
who settle and change the planet?
owned only by rich nations who can
afford the costs to reach the site?
Who is entitled to use its resources?
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space resources could satisfy our energy
needs on Earth for a long time
minerals from asteroids
capturing solar energy and beaming it to
Earth
cost of space travel could be cut substantially
by creating space vehicles, supplies, etc
directly in space
the Moon can supply hydrogen as fuel for
lunar bases and space travel/oxygen for life
support/both hydrogen and oxygen used for
water supply
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Is a space treaty needed?
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use space exclusively for peaceful
purposes
not used as the scene or object of
international discord
maybe have nations collaborating
similar to the Antarctica Treaty
System
Who is responsible for cleaning up the
space environment?
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How can we justify spending billions of
dollars to send a few people into space when
millions of people on Earth do not have clean
drinking water?
looking for extra space to house people as
the population keeps growing
increase in employment available as other
planets are colonized
send robots instead of humans as less
danger and cost are involved (lose first-hand
experience of humans if we do this)