Download Unit 4 Space

10.1 The Early Universe
• Until 100 years ago, scientists believed
nothing ever changed in outer space.
• Using powerful telescopes, astronomers like
Edwin Hubble discovered many new
celestial bodies, and observed that
everything in the universe was moving
further apart.
• The universe expands like baking bread;
galaxies and other celestial objects are like
raisins in the dough, moving apart as the
bread bakes.
See pages 346 - 347
(c) McGraw Hill Ryerson 2007
Red Shift Analysis
• By examining the light from distant stars, astronomers can estimate the
speed and directions the star is traveling.
• Light, like all forms of electromagnetic radiation, travels in waves. Objects in
space give off many different forms of radiation.
• Like the sound of a ambulance siren changes as it passes you, light from
stars exhibits red-shift, indicating speed and direction of motion.
• A spectroscope analyzes the unique spectrum of a star, which astronomers
can analyze to discover the direction and amount the light has shifted.
• A red shift means the wavelength is getting longer,
and the star is moving away from us.
• Blue shift is the opposite; the star is getting closer.
See pages 348 - 349
(c) McGraw Hill Ryerson 2007
The Big Bang Theory
• Once astronomers realized everything was moving away from
everything else, they realized the universe might have originated
from a single point.
• The Big Bang theory suggests that everything in the universe came
from a single starting point, approximately 13.7 billion years ago.
• Although there are other theories about the
beginning of the universe, much scientific
evidence supports the Big Bang theory.
• The Big Band is also supported by the presence
of cosmic background radiation, which is the
energy left over from the Big Bang.
• This radiation was mapped by the COBE and
WMAP explorations.
Take the Section 10.1 Quiz
(c) McGraw Hill Ryerson 2007
See pages 350 - 352
10.2 Galaxies
• Our star, the sun, is one of 100 million stars in
the Milky Way galaxy - and there are 125 billion
galaxies in the universe!
• A galaxy is a large group of stars. A nebula is a
cloud of gas and dust in space that is often
produces a new star, or is the remains of an old
star.
• Galaxies can be spiral, elliptical or irregular in
shape.
• How fast a galaxy spins helps define its
shape.
• Each galaxy has stars clustered as globular
clusters or open clusters.
Take the Section 10.2 Quiz
(c) McGraw Hill Ryerson 2007
See pages 356 - 360
11.1 Stars
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A star is a massive sphere of gases with
a core like a thermonuclear reactor.
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The most common celestial bodies in the
universe are stars.
It is estimated there are more stars in the
universe than there are grains of sand on
all the beaches on Earth.
By peering through the interstellar matter
(dust and gases), astronomers an
observe the birth of stars.
See pages 368 - 369
(c) McGraw Hill Ryerson 2007
The Birth and Life of Stars
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Stars form from the dust and gases found in a nebula, when enough gravity
causes all the molecules to collapse in on themselves.
• If enough matter gathers, the gravity
becomes so massive that hydrogen atoms
join to form helium atoms, producing huge
amounts of energy through the process of
fusion.
• It is the energy given off by fusion that
causes stars to glow.
• The life cycle of a star: nebula, low mass
star, intermediate mass star (like our Sun),
high mass star. Large high mass stars often
explode as supernovas, spreading elements
throughout the universe.
See pages 370 - 371
(c) McGraw Hill Ryerson 2007
•
Stars 12 - 15 times more massive than our Sun can end as neutron stars after
going supernova. These superheated, super massive dead stars can take
trillions of years to cool.
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Stars 25 times as massive as our Sun can
become black holes instead of neutron stars.
The same process that produces a neutron
star produces an area so massive and yet so
small that the gravity it produces traps
everything - even light!
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Stars can vary greatly in size. Although our Sun is an average size, many of
the stars we see in the night sky are up to 3000 times as large as the Sun.
See pages 372 - 373
(c) McGraw Hill Ryerson 2007
The Hertzsprung-Russell Diagram
• By studying stars, astronomers have have created an evolutionary
‘lifespan’ that stars progress through.
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The Hertzsprung-Russell
diagram was developed to
show the different stages of
a star’s life.
90% of stars are in the main
sequence, where energy is
produced combining
hydrogen atoms into
helium.
Blue
Red
See page 374
(c) McGraw Hill Ryerson 2007
Analyzing Star Colour
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The colour of a star reveals its temperature and composition to astronomers.
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Red stars = cool = 3000 ºC
Yellow stars = hot = 6000 ºC
Blue stars = hottest = 20 000 ºC - 35 000 ºC
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Using a spectroscope, the light emitting from a star reveals spectral bands that
show certain gases in the star.
• Of course, spectral lines are also used to identify the movement of stars by
utilizing red-shift analysis.
• Red-shift is an example of the Doppler effect, which states that as a waveemitting object moves, the wavelength of its waves change.
See pages 374 - 375
(c) McGraw Hill Ryerson 2007
Colour and Motion
• The Doppler effect refers to the way waves either compress as their
source gets closer, or lengthen as the source gets farther away.
• The unique spectral pattern each star reveals when examined through a
spectroscope allows astronomers to see if the lines shift towards the red
part of the spectrum (moving away) or blue (moving closer).
Take the Section 11.1 Quiz
(c) McGraw Hill Ryerson 2007
See pages 376 - 377
11.2 The Sun and the Planets
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Our Sun, an average star in the universe, is the center of our solar system.
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Our solar system is full of planets, moons, asteroids and comets, all of
which revolve around the Sun at the center.
When a star forms from a nebula, gravity pulls most of the material into the
new star, but some may also clump together to form objects in a solar
system.
• A planet is a celestial body that orbits one or more stars.
• Each planet may also spin on its axis (rotates) while it orbits the Sun (revolves).
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Our solar system formed approximately 4.5 billion years ago. The four inner,
rocky planets in the first 100 million years on the Sun’s existence, while the
outer, gaseous planets formed later from the remnants of the Sun’s original
nebula.
See pages 382 - 383
(c) McGraw Hill Ryerson 2007
The Sun
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The Sun contains 99% of all the mass found in our solar system.
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The Sun has a diameter equal to 110 Earths.
The Sun is made up mostly of hydrogen. The hydrogen molecules are forced to join
together through massive gravity, forming new helium molecules, and releasing
huge quantities of energy as light and heat through the process of thermonuclear
fusion.
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The Sun has no solid surface, but has distinctive
features such as sun spots, flares and prominences.
The photosphere is the surface of the Sun. It looks
blotchy due to rising and cooling gases.
The corona is the outer portion of the Sun’s
atmosphere.
See pages 383 - 384
(c) McGraw Hill Ryerson 2007
Solar Winds
• Sometimes, gases from the Sun’s corona erupt outwards like a
bursting soap bubble.
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The resulting solar wind is full
of high-energy particles that
would kill any life on Earth
they struck.
Luckily, our magnetic field
deflects this solar wind. We
can see these particles being
deflected when we see the
Northern Lights.
Large outbursts of solar winds
can wreak havoc with
satellites as well as Earthbound energy supplies such
as power plants.
(c) McGraw Hill Ryerson 2007
See page 385
The Planets
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To be considered a planet, a body must orbit one or more stars, be large
enough that its own gravity holds it in a spherical shape, and be the only body
occupying the orbital path.
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Distances between planets in the solar system are measured in astronomical units
(AU). One AU = the average distance from the Sun to the Earth.
The inner planets are relatively close to the center of the solar system - Mars is
1.52 AU from the Sun. The next planet, Jupiter, an outer planet, is 5.27 AU from
the Sun. The most distant planet, Neptune, is 30.06 AU from the Sun.
Inner, rocky planets
Outer, gaseous planets
Mercury
Smallest planet
Jupiter
Largest planet
Venus
Earth’s sister
Saturn
Rings + many moons
Earth
Only life in universe
Uranus
Methane gas planet
Mars
The red planet
Neptune
Outermost planet
See pages 385 - 387
(c) McGraw Hill Ryerson 2007
Other Solar System Bodies
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There are also numerous celestial bodies smaller than planets in our solar
system.
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Moons are found around all planets except Mercury and Venus.
Asteroids are found mostly between Mars and Jupiter in the steroid belt. It is
thought these are ‘leftovers’ from the formation of the solar system.
Comets (sometimes called “dirty snowballs”) are actually rocky travelers, following
huge orbits far outside the planets in the Oort Cloud.
Trans-neptunian objects refer to objects outside Neptune’s orbit, including ex-planet
Pluto (now referred to as a dwarf planet). These objects orbit the Sun in a lagre area
known as the Kuiper Belt.
The Oort Cloud is at the farthest reaches of the Sun’s gravitational pull, almost 25% of
the way to the next nearest star, Proxima Centauri.
Take the Section 11.2 Quiz
(c) McGraw Hill Ryerson 2007
See pages 388 - 389
11.3 Measuring Distances in Space
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We use AUs for distances within our solar system, and light years for distances
outside our solar system.
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A light year is the distance light travels in one year = 9.5 trillion km.
Even the light from the nearest stars takes several years to reach the Earth.
The light that we see from more distant stars has taken thousands, or even
millions, of years to reach the Earth.
Astronomers use red-shift to determine motion, and can use triangulation
and parallax to calculate position.
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Triangulation uses geometry to estimate actual distances between objects in space.
Parallax is a method that uses changing position to provide a baseline for triangulation.
See pages 396 - 398
(c) McGraw Hill Ryerson 2007
Techniques for Indirectly Measuring Distance
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Since it is impossible to measure actual distances in space, astronomers use
mathematical methods to estimate distances.
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Triangulation uses the geometry of a triangle to find the distance to far away
objects.
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First, a baseline is measured. The longer the baseline, the more accurate
the distance measurement will be
Next, measure the angles from each end of the baseline to the object.
Next, draw a scale diagram that represents the baseline measurement
and the two angles out to the distant point.
Finally, by measuring the height of the triangle that forms, you find the
distance to the object.
Baseline distance
Scale: 1 cm = 100 m
(c) McGraw Hill Ryerson 2007
See pages 399 - 400
Techniques for Indirectly Measuring Distance
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Since it is impossible to measure actual distances in space, astronomers use
mathematical methods to estimate distances.
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Parallax works in a similar way to triangulation, except the baseline we use
is huge - the diameter of the Earth’s revolution around the Sun!
Parallax refers to the concept that objects closer to us appear to change
position compared to objects much farther away.
First, the baseline is measured. Astronomers can very accurately record the
diameter of the Earth’s orbit around the Sun.
Next, measure the angles from each end of the baseline to the object. In
this case, each end of the baseline will occur 6 months apart!
Next, draw a scale diagram that represents the baseline measurement and
the two angles out to the distant point.
Finally, by measuring the height of the triangle that forms, you find the
distance to the object.
Take the Section 11.3 Quiz
(c) McGraw Hill Ryerson 2007
See page 401
12.1 Earth, Moon and Sun Interactions
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Humans have been aware of the relationships between the Earth, Sun and
Moon for thousands of years, but only recently have we began to better
understand the true nature of these relationships.
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Ancient civilizations used the seasons, months, position of stars and other
astronomical information in many parts of their lives.
Until the past few hundred years, humans believed the Earth was the center of
the universe (the geocentric model).
• The geocentric model was based on the work of the ancient Greek
philosopher Ptolemy
We now observe the heliocentric model, where the Sun is the center of the solar
system, and the universe expands outward.
• The heliocentric model is based on the observations of Copernicus and
Galileo.
See pages 410 - 411
(c) McGraw Hill Ryerson 2007
The Moon
• Earth’s nearest neighbour in space is the Moon, a natural satellite
that most likely formed from a collision between the Earth and a
Mars-sized planet during the formation of the solar system.
• The surface of the Moon, which can be
seen clearly with good binoculars, is
not protected by an atmosphere like
the Earth’s.
• The surface of the Moon is bombarded
with space debris, but also does not
suffer from erosional forces like wind
and water.
• Light-coloured surfaces are highlands
made of very old rock, while darker
surfaces are called mare, and are
lower, flat stretches of basalt.
See page 412
(c) McGraw Hill Ryerson 2007
Phases of the Moon
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The Moon, reflecting light from the Sun, appears to change in size and shape as it
rotates on its axis and revolves around the Earth.
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It takes the Moon 29.5 days to make a complete orbit around the Earth. During
this time, different portions of the Moon can be viewed as the changing phases.
• Interestingly, the Moon rotates at almost the same rate as it revolves,
meaning that the same surface of the Moon (the “near” side) always faces
the Earth. The “far” side is always facing away from the Earth!
• What we see as the changing phases are actually just different viewing
points of the Moon’s “daylight”, time periods when the Sun shines on the
Moon.
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The Moon’s gravity pulls on the oceans on Earth to create tides.
See pages 412 - 413
(c) McGraw Hill Ryerson 2007
The Earth’s Rotation and Tilt
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The time it takes the Earth to revolve around the Sun is 365 days (one year).
Every 23 hours and 56 minutes (one day), the Earth rotates on its axis. The tilt of
the Earth’s axis gives us seasons.
• As the Earth rotates, it is tilted at 23.5º from vertical. Depending on what part of
the year (orbit around the Sun) and which hemisphere (North or South) you are
at, your location will either be tilted toward the Sun (summer) or away (winter).
• At the equator, the Sun’s energy strikes the Earth the same all year long - in other
words, there are no seasons!
• It is this tilt that also changes the length of the daylight hours each part of the
Earth receives.
• The shortest day (Winter solstice) occurs when we are tilted the most away from
the Sun, while the longest day (Summer solstice) occur when the tilt is closest to
the Sun.
• The Spring and Autumnal equinoxes occur when the number of hours of light and
dark are equal.
See pages 414 - 415
(c) McGraw Hill Ryerson 2007
Eclipses
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An eclipse occurs when a celestial object obscures the normal view of
another celestial object.
• Eclipses frightened ancient peoples, who believed supernatural forces
controlled the Sun and Moon.
• Solar eclipses occur when the Moon comes between the Earth and the Sun.
Normal daylight disappears, and only small amounts of light make it to the
Earth during the few minutes it takes the Moon to pass between the Earth
and Sun.
• The Moon is so small, its full shadow only covers a small portion of the
Earth. This area is said to undergo a total eclipse.
• Lunar eclipses occur when the Earth comes between the Moon and the Sun.
The Earth’s shadow causes the full moon to slowly disappear, again taking a
few minutes before the shadow passes.
• Lunar eclipses happen far more frequently than solar eclipses.
See pages 416 - 418
(c) McGraw Hill Ryerson 2007
Constellations and Meteors
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Ancient civilizations studied the night sky for patterns, and created many
myths based on patterns they recognized from their lives.
• The night sky appears to be flat because of the huge distances between
stars, but actually the stars in one constellation can be several thousand, or
even millions, of light years apart!
• In the northern hemisphere, the “pointer stars” of Ursa Major show the
location of the North Star, Polaris. The location of Polaris is special, as it
does not change position throughout the year, unlike all other stars.
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Meteoroids are pieces of space rock floating through space without a
specific orbit. When they pass through the Earth’s atmosphere, they begin
to heat from friction, and are called shooting stars. If any of the meteoroid
reaches the Earth’s surface, it is called a meteorite.
Take the Section 12.1 Quiz
(c) McGraw Hill Ryerson 2007
See pages 419 - 420
12.2 Aboriginal Knowledge of the Solar System
• Long before modern science, the Aboriginal peoples of the West
Coast developed systems based on observations of space and
celestial bodies.
• Aboriginal cultures have a holistic world view, where all realms of the
physical and spiritual world are connected to form a whole. Western
science is based on the physical realm only.
• Observations of the Sun and Moon allowed for the development of
hunting, fishing and agricultural cycles.
• By observing the position of celestial objects in the sky, accurate
navigation and distance calculations could also be made.
See page 426
(c) McGraw Hill Ryerson 2007
Aboriginal Knowledge of the Solar System
• The aboriginal peoples of British Columbia made daily decisions
using their knowledge of the moon, planets and stars.
• Fishing was often influenced by lunar positioning.
• It was observed that there were 13 lunar months, of 29.5 days,
throughout the year.
• The Coast Salish, for example, named these lunar months, and
associated each with knowledge of connected seasons, cultural
activities and traditions.
• Navigation was often determined by the positions of the stars and
planets in the night sky.
• By recognizing the patterns the stars and planets followed,
predictable seasons were followed from year to year.
Take the Section 12.2 Quiz
(c) McGraw Hill Ryerson 2007
See pages 427 - 429
12.3 Exploring Space: Past, Present and Future
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Until the invention of the telescope, knowledge of space
was very weak, and mythology and speculation were the
rule.
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The telescope was invented in the 17th century by the
Dutch eyeglass maker Lippershey.
There are two main types of optical (light) telescopes:
refracting and reflecting.
• Refracting telescopes use lenses to gather and focus
light
• Reflecting telescopes use mirrors to collect light and
project it onto an eyepiece.
See pages 432 - 433
(c) McGraw Hill Ryerson 2007
Non-Optical Telescopes
• Early optical telescopes improved viewing of space greatly, but other
electromagnetic waves could also be used to gather information
about space.
• X-rays, gamma rays and radio waves
can all be gathered and analyzed to
learn about space.
• Radio telescopes look like satellite
dishes.
• By joining radio telescopes together in
a network, results can be obtained as
though one very large telescope was
being used.
From the Commonwealth Scientific and
Industrial Research Organization
See pages 434 - 435
(c) McGraw Hill Ryerson 2007
Space-based Observation
• As good as many of the telescopes on Earth are, by moving outside
the atmosphere, space-based observation has become our most
powerful method of space observation.
• Satellites launched from Earth provide us with
communication and safety every day.
• Geosynchronous satellites orbit at the
same rate as the Earth rotates, and stay
above one point.
• Probes launched from Earth have visited
Venus, Mars and Saturn’s moon Titan, and
have traveled through space to the far
reaches of our solar system.
• Rovers are used to maneuver scientific
equipment after landing on planets and
moons.
The surface of Saturn’s moon Titan.
See pages 435 - 438
(c) McGraw Hill Ryerson 2007
The Technology of Space Travel
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The challenge of using rockets to launch scientific equipment - and
astronauts - into space now sees us attempting to establish colonies in
space.
• A rocket is used whenever we want to get something - called a payload
- into space.
• The rocket has a large amount of thrust, and very little drag, in order
to break through the Earth's atmosphere.
• The space shuttle program also uses rockets for launch, but also relies
on having the equipment return to Earth safely for return trips.
• The International Space Station is an attempt to provide a location in space
from which to operate without needing to always use rockets to get there.
See pages 439 - 440
(c) McGraw Hill Ryerson 2007
Space Travel
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Early attempts at space travel were unmanned, or carried animals. In the past
40 years, we have sent humans into space, as well as having them return safely.
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International collaboration promotes friendly politics.
Canadians have aided in space travel by contributing to the development of the
International Space Station, as well as work on the Canadarm system for the Space
Shuttle, as well as sending astronauts on space missions.
Many technological advancements have occurred due to research done for space
travel.
Soon, average citizens may be able to afford to travel into space for recreational
purposes.
Terraforming is a process where previously uninhabitable locations, such as the Moon
or Mars, would be changed to look and function as Earth does.
See pages 441 - 442
(c) McGraw Hill Ryerson 2007
The Risks of Space Travel
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Perhaps more than in any other area, space travelers rely heavily on the
equipment used for travel to provide safety.
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Two shuttle failures have resulted in the loss of several astronauts.
Our equipment is very sensitive to the debris found in space, from large fuel
tanks to small flecks of paint.
• Sometimes, this debris can also re-enter the Earth’s atmosphere and
threaten us on the surface.
Space poses a huge advantages to those who control it, and have access to its
resources.
• Environmental, safety and political concerns can arise if we do not use
space ethically.
See pages 443 - 444
(c) McGraw Hill Ryerson 2007
New Ideas for Interplanetary Travel
• To reach farther into space, particularly for manned missions, new
methods of transportation will be necessary.
• Our current space travel technology uses very large amounts of fuel to
travel relatively short distances with very few passengers.
• The ‘space sled’ uses magnetic technology to help propel a small craft
without the use of much fuel.
• A ‘space elevator’ would be very useful for moving people and materials
into space without the constant use of rockets.
Take the Section 12.3 Quiz
(c) McGraw Hill Ryerson 2007
See page 445