Space exploration

1
Space exploration

• Unit 2 (textbook Unit 4)

2
KWL Chart

• Copy down the following chart (make it about a
  page long)
• First, write what you already know about space
  (point form) anything you can think of that you
  know for sure.
• Then, write what you want to know about space
  that you dont know already.
• You will keep the table in your portfolio. At the
  end of the unit, you will take your chart out
  again and write down what youve learned.

KNOW WANT TO KNOW LEARNED

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What is all that stuff up there?

• Any natural object in space such as a planet, a
  moon, an asteroid, a comet or a star is called a
  celestial body.
• Early civilizations would make note of the
  movement of celestial bodies so that they would
  know when a good time to plant their crops would
  be. The stars and planets served as the first
  calendars.

4
Constellations

• Groups of stars that make a pattern are called
  constellations. Ancient Greeks and Romans would
  label the constellations after characters from
  their mythologies.

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Common Constellations

• Three common constellations are
• Ursa Major (The Great Bear)
• Ursa Minor (The Little Bear)
• Orion

Ursa Major
Orion
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Asterisms

• Asterisms are smaller groups of stars that are
  present within constellations. Examples of these
  are
• The Big Dipper (In Ursa Major)
• The Little Dipper (In Ursa Minor)
• Orions belt (In Orion)

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Movement of the Stars

• Stars in the sky look as if theyre moving from
  East to West. This is caused by the Earths
  rotation on its axis.
• If you look south, the stars look like they rise
  in the east and set in the west.
• If you look to the north, the stars look like
  theyre all spinning (slowly) around one common
  point. This point is the North Star (Polaris).
  The stars spin around this point because the
  Earths axis points directly at Polaris this
  makes it appear stable compared to the other
  stars.

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Axes

• Singular axis Plural axes
• Axes are imaginary lines through a star, planet,
  moon or other celestial body that represent the
  point at which the planets revolve. All celestial
  bodies rotate on a central axis.
• The Earths axis runs from the North Pole through
  to the South Pole. The Earth is actually tilted
  in space on its axis (the North pole isnt the
  highest part of the Earth in space). One full
  rotation of the Earth takes about 24 hours.
• Jupiter rotates the fastest, taking only about 10
  hours. Venus takes the longest about 243 Earth
  days.

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Orbits and Ellipses

• An orbit is the regular path of a celestial body
  around another, larger celestial body.
• In our solar system, the largest celestial body
  is the Sun. The Sun follows the same path (orbit)
  every day. The line that the Suns orbit follows
  is called the ecliptic. It was named this because
  eclipses only happen when the Moon is close to
  crossing this line.
• The Moon and Planets all follow paths (orbits)
  that are close to the ecliptic.
• It was originally thought that the Sun, the Moon
  and all of the planets followed orbits that were
  perfect spheres. We have since learned that the
  paths they follow are actually ellipses.
• Ellipses are oval-shaped. The reason for this is
  that while the Sun is large and near the centre
  of the solar system, the planets and other
  celestial bodies also influence the gravitational
  pull of each other. This results in the orbits
  being stretched out and gives the orbits their
  elliptical shape.

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Orbits Gravity

• Orbits are the result of a perfect balance
  between the forward motion (momentum) of a
  celestial body in space, such as a planet or
  moon, and the pull of gravity on it from another
  celestial body in space, such as a large planet
  or star.
• An object with a lot of mass goes forward and
  wants to keep going forward however, the gravity
  of another body in space pulls it in. There is a
  continuous tug-of-war between the one object
  wanting to go forward and away and the other
  wanting to pull it in.
• This simulation shows what might happen in the
  forward momentum of the Earth or Moon were to
  change.

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Motion of the Planets

• The planets all move at different rates around
  the ecliptic. The closer a planet is to the Sun,
  the faster it will move around its orbit.
  Therefore, Mercury will move the fastest. To
  remember the order of the planets from closest to
  farthest from the Sun, use this phrase
• My Very Earnest Mother Just Served Us Nine Pizzas
• (Mercury, Venus, Earth, Mars, Jupiter, Saturn,
  Uranus, Neptune, Pluto - Dwarf Planet)
• Mercury and Venus are inside the Earths orbit
  around the Sun, and can only been seen setting
  just after sunset or rising just before sunrise.
  The planets outside the Earths orbit can be seen
  all night long, depending on their position
  relative to the Earth.

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Movement of Asteroids and Comets

• Comets and asteroids are two different things.
  Comets are made up of rocks and ice, and their
  tails can be seen only when theyre pushed into
  the inner solar system (near the Sun). Some
  comets have orbits that take them way out to the
  edge of our solar system.
• Asteroids are made of rock, and most orbit the
  Sun between Mars and Jupiter. Those that can been
  seen appear as if they move with the orbits of
  Mars and Jupiter.

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Theories about the Universe

• Just like with atoms, we know a lot about the
  universe because of different theories that
  people started developing a long time ago.
• Some of these theories have been completely
  discarded, while other have been accepted or
  built on.

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Aristotle

• Aristotle thought that the universe was
  geocentric. This means that he thought the Earth
  was the centre of the universe, and that the sun,
  moon, stars and other planets revolved around it.
• He based this theory on the fact that he did not
  see the patterns of the stars in the sky change,
  so he assumed that the Earth was not moving
  because if it was the star patterns would also
  move.
• Aristotle was the first person to suggest that
  the Earth was a sphere based on shadows he saw on
  the moon during a lunar eclipse. He also proposed
  that the fact that the constellations that you
  can see change as you go from North to South
  showed that the Earth was a sphere.

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Aristotle

• Aristotle explained the apparent motion of
  celestial bodies by placing all of the celestial
  bodies seen from Earth on 22 concentric spheres.
  He said that these spheres moved at different
  speeds, which caused the different observations
  about the movement of the planets.

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Ptolemy

• Aristotles model of the universe did not explain
  all of the things that people observed. For
  example, if you watch Mars every night for a few
  weeks and map its position, youll notice that it
  travels in an S pattern. It heads east, slows
  down, stops, and then heads west for weeks.
• Ptolemy watched Mars very closely, and added to
  Aristotles model of the universe to explain the
  way that Mars moved.

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Copernicus

• Copernicus lived before the telescope was
  invented. He was the first to propose a
  heliocentric (sun centric) solar system. Using
  just his eyes, he observed that the movements of
  celestial bodies that others had noticed could be
  explained by the Earth rotating on its axis once
  a day and orbiting the Sun once a year.
• Copernicus and others who supported him placed
  themselves in danger. Copernicus actually held
  off telling people about his theory until he was
  near death. Another astronomer, Bruno, who agreed
  publicly with Copernicus was burned at the stake.

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Galileo

• As we learned last year, Galileo invented one of
  the first telescopes. Using his telescope, he was
  able to make a lot of observations that no one
  could have before, and build on existing
  theories.
• One important observation was that Venus had
  phases, like the Moon. This lent more evidence to
  the heliocentric solar system Venus could not
  have phases if it did not orbit the Sun.
• Galileo was put on trial and found guilty of
  heresy for publishing his theory. He was put in
  prison for the rest of his life.

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Questions in Textbook

• Answer Questions 1 to 10 on page 375 in your
  book, EXCEPT NUMBER SEVEN!!
• Use pages 366 to 374 and your notes to help you.

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Kepler

• Kepler worked with a man named Brahe. They
  watched the planet Mars for weeks and tried to
  work out a model for how it moved. They found
  that a spherical orbit didnt help to explain
  Mars movement. When they tried an elliptical
  orbit, everything fell into place.
• Based on his work, Kepler developed 3 laws of
  planetary motion.

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Keplers Laws of Planetary Motion

1. All planets move around the Sun in ellipses.
2. When a planet gets closer to the Sun it speeds
   up, when its further away it slows down.
3. The time a planet takes to revolve around the Sun
   is in direct proportion to how far away it is
   from the Sun (i.e. Mercury will orbit the
   fastest, Neptune/Pluto the slowest depending on
   which one is considered the last planet).

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Newton

• Newton was the first to show that the force of
  gravity
• extends past the surface of the Earth
• affects all celestial bodies, causing them to
  orbit larger celestial bodies (moons around
  planets, planets around the Sun, etc).
• Newton invented the reflecting telescope (using
  mirrors lenses instead of just lenses).
• This allowed the telescope to be larger in size
  and give more exact images.

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Astrolabes

• Astrolabes are used to show how the sky looks at
  a specific place at a given time. This is done by
  drawing the sky on the face of the astrolabe and
  marking it so positions in the sky are easy to
  find. To use an astrolabe, you adjust the
  moveable components to a specific date and time.
  Once set, much of the sky, both visible and
  invisible, is represented on the face of the
  instrument. This allows a great many astronomical
  problems to be solved in a very visual way.
  Typical uses of the astrolabe include finding the
  time during the day or night, finding the time of
  a celestial event such as sunrise or sunset and
  as a handy reference of celestial positions.
• astrolabes.org

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Stone Circles

• Stone circles are found all over the world,
  although most are in Europe. Archaeological
  evidence indicates that in addition to being used
  as places of burial, the purpose of stone circles
  was probably connected to agricultural events,
  such as the summer solstice. Although no one
  knows for sure why these structures were built,
  many of them are aligned with the sun and moon,
  and form complex prehistoric calendars. Although
  we often think of ancient peoples as being
  primitive and uncivilized, clearly some
  significant knowledge of astronomy, engineering,
  and geometry was needed to complete these early
  observatories.
• http//paganwiccan.about.com/od/sacredplaces/p/Sto
  ne_Circles.htm

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In your notebook

• Describe for each planet (p. 400-401)
• Size (Diameter!)
• Shape (Dont just say a sphere!)
• What its made of
• Approx. distance from the Sun (given in AUs
  astronomical unit 1 AU distance between the
  Earth and the Sun
• Length of a day
• Length of a year
• Average temperature
• Colour
• Two interesting facts 

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Use pages 390 to 394 and 402-407 to answer the
questions below

• A thermonuclear reaction is
• How many hydrogen atoms fuse together in the Sun
  to form helium?
• How long has the Sun been giving off light?
• How much longer will the Sun last?
• What is solar radiation?
• Solar radiation and what other force need to be
  in balance to keep a star from collapsing?
• Describe
• Sun-spots
• solar flares
• solar prominences

• What is solar wind?
• Why doesnt solar wind affect us on Earth? 
• Moons are also called
• How did the Earths moon form?
• What is a dwarf planet?
• How many Dwaft Planets are in our solar system?
  What are their names?
• What is an asteroid?
• What is the size range for an asteroid?
• What is a comet?
• Periodic comets have an orbit of less than 200
  years. What is the periodicity of Halleys Comet?
  When was it last visible from Earth?
• What is a meteoroid? How is it different from a
  meteorite?
• Answer questions 1-14 on page 411 in your book.

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Canada in Space

• Canadians have made several important
  contributions to space exploration
• The Canadarm this piece of technology is mounted
  on the International Space Station and allows
  astronauts to sent out satellites, retrieve them,
  move large payloads, dock the space shuttles that
  arrive at the station, and help astronauts
  perform repairs and maintenance on the station.
• The MOST this stands for Microvariability and
  Oscillations of Stars Telescope. Developed by
  Canadians, this satellite is about the size of a
  suitcase and orbits the Earth in about 100
  minutes. The satellite detects when the light
  from distant stars is dimmed slightly, which
  tells us that a planet has passed in front of it.
  These differences are extremely tiny so the
  equipment on the MOST must be very sensitive.

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How Can We Explore the Universe?

• Rocket Propulsion Rockets transport astronauts
  and materials into space. At the beginning of the
  space program, animals were sent to make sure
  that the rockets were safe for humans. Some
  animals sent included several types of monkeys,
  chimpanzees, dogs and cats (mammals were
  preferred because they most resembled people).
• Rockets travel by thrust (think of letting go of
  a balloon that youve almost completely blown
  up). As the fuel on a rocket gets used up, parts
  of the rockets propulsion system break off from
  the rocket to make it lighter (and therefore
  require less fuel).
• 2. Space Suits Space suits act as tiny
  spaceships that provide oxygen to breathe,
  temperature control, communication systems
  (imagine getting lost on a space walk with no one
  to call for help), and pressure control.

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• 3. Satellites these are artificial devices that
  orbit the Earth and send information. There are
  several types of satellites including
  communication satellites, remote sensing
  satellites, and telescope satellites like the
  MOST.
• Satellites can travel in different types of
  orbits. The further away the satellite is from
  the Earth, the longer it will take to orbit
• Low Earth Orbit between 300-500km above the
  Earth. These satellites travel around the Earth
  once every 90 minutes.
• Geosynchronous orbit satellites placed above the
  equator a distance of about 36 000km. These
  satellites take about 24 hours to make one orbit.
  Because they are rotating at the same rate as the
  Earth, these satellites appear to stay in the
  same place. Communication satellites are usually
  placed in geosynchronous orbit.

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• 4. Probes Probes are unmanned space crafts sent
  to other celestial bodies to gather information.
  They can fly past, orbit, or land on these
  bodies. All of the planets in our solar system
  have been visited by a probe, and a recent probe
  sent to Pluto is set to arrive in 2015. Probes
  send images and information directly back to the
  Earth.
• 5. Rovers Rovers are like the ROVs that we
  learned about last year, only designed for outer
  space rather than the bottom of the ocean. Rovers
  have highly specialized programming so that they
  can problem solve and are designed to withstand
  extreme temperatures (freezing cold to blistering
  heat). They are designed to work all day long and
  conserve battery power at night.

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• 6. Optical telescopes these include both
  refracting (lenses only) and reflecting (lenses
  and mirrors) telescopes. Large observatories
  (labs that contain huge telescopes) are typically
  built high on mountaintops above most of the air
  so that they are not hindered by atmospheric
  conditions.
• 7. Radio telescopes Radio telescopes collect
  wavelengths along the electromagnetic spectrum
  that are longer than visible light. Radio
  telescopes have large receivers that look like
  giant satellite dishes. They convert the radio
  signals to electric impulses that are used to
  discover details about celestial bodies that you
  would not be able to find out with optical
  telescopes.

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Solar Systems, Galaxies and the Universe

• Solar systems make up galaxies which make up the
  universe, just like cities and towns make up
  counties/provinces/states which make up countries
  which make up the world.
• Solar systems consist of a star and all of the
  celestial bodies that orbit around that star.
• Galaxies are made up of several stars, planets,
  gas, and dust all held together by gravity.
• The Universe consists of all matter and energy.

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The Big Bang Theory

• The theory states that about 13.7 billion years
  ago, a tiny volume of space suddenly and rapidly
  expanded into a gigantic size. In a short time,
  all matter and energy in the universe was formed.
  The theory was first proposed by Georges Lemaître
  in 1927. The temperature of the Big Bang was over
  1 000 000 000 oC. The universe has been cooling
  ever since.

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The Oscillating Theory

• Oscillating theory states that not only did the
  universe undergo a Big Bang, but that it will
  also someday undergo a Big Crunch. The idea is
  that the universe is closed and that there is
  enough matter to eventually stop the expansion of
  the universe, and through gravitational force,
  reverse it.
• This is in contrast to open universe theories
  (like the Big Bang theory) which state that the
  universe is expanding and that the rate of
  expansion is increasing (getting faster) over
  time.

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Theories about our Solar System

• There are two main theories about how our solar
  system was formed
• Stellar Collision Theory this theory proposes
  that the planets and our Sun came from collisions
  between stars (like the theory of how the moon
  was formed).
• The Nebular Hypothesis this theory states that
  the Sun and planets were formed when a large
  nebula condensed and formed together by gravity.
  It is suggested that a nearby star could have
  exploded and started the condensing of the
  nebula. This is the more accepted theory.

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Distances in Space

• We have already learned about astronomical units
  (AUs). 1 AU is equal to the distance between the
  Earth and the Sun (149 597 870.691 kilometres, or
  approximately 150 million).
• Light years are used when distances get up to
  millions of AUs. Basically, if you are
  travelling at the speed of light, it will take
  you one year to cross the distance of one light
  year. Light travels at about 300 000km/s. One
  light year is just about 9.5 trillion
  (9 500 000 000 000) kilometres.

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Major Components of the Universe

• Nebula a cloud of gas and dust in space, where
  stars are formed.
• Elliptical Galaxies a galaxy with a spherical to
  an elliptical shape that contains some of the
  oldest stars in the universe. Some look like a
  baseball, some like a football, some like a
  cigar. The largest galaxies in the universe are
  elliptical.
• Spiral Galaxies Galaxies made with long arms
  that spiral out from each other from a centre
  core. The Milky Way is a spiral galaxy.

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Major Components of the Universe

• High Mass Stars Stars that have 12 or more times
  the mass of the Sun. These stars burn out very
  quickly. Become red supergiants and then collapse
  into neutron stars or black holes.
• Intermediate Mass Stars become red giants and
  supernova into nebula.

• Low Mass Stars become red giants and shrink into
  white dwarves.

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Major Components of the Universe

• Quasars a region of extremely high energy that
  develops as the supermassive black hole in the
  centre of a galaxy attracts more matter into
  itself.
• Black Holes a large sphere of incredibly tightly
  packed material with a huge gravitational pull
  created when a star collapses on itself. Nothing,
  not even light, can escape the gravitational
  field. Because of this, not one knows what they
  look like.

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Unit Review

• Starting on page 474, answer questions
• 2 to 14

41
Unit Review

• Starting on page 474, answer questions
• 18, 20, 21,
• 23 to 25

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Unit Review

• Starting on page 474, answer questions
• 29, 30, 32, 33, 37,
• 39, 40, 43, 45 49