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Space Exploration

VIEWS: 6 PAGES: 47

									Space Exploration

Astronomy
What Can We See
in the Sky?

4.1
Things you see
when you look up in the sky:
 Sun
 Moon
 Airplanes
 Satellites
               On a clear night away
 Stars
               from the city lights
 Planets
               http://pages.prodigy.net/pam.orman/joemoon/planets_010328_28.jpg
    Star Constellations

                                                    When groups of
                                                     stars look like
                                                     – Animals
                                                     – Ancient heroes/gods
                                                     – Everyday objects
                                                    Ex. big dipper, little
                                                     dipper


http://antwrp.gsfc.nasa.gov/apod/ap960902.html
Star Constellations cont

   Predictable so they are sometimes used
    – as Calendars
    – To keep time
    – To find a direction
Solar System

   Made up of the
    – Sun
    – Planets
    – Other stars
Give off light?

   Planets do not give off light
    – Called non-luminous
   The Sun and other stars give off light
    – Called luminous
   Observing Stars and Planets

                                Stars
                                 give off a lot of heat
                                  and light
                                 Are further away so
                                  they appear smaller
                                 Ex. Sirius, Polaris




http://www.kidsastronomy.com/
Observing Stars and Planets
Planets
 Shaped like a ball
 Follow a set path around the Sun
 Are closer so they appear larger
 Ex. Mercury, Venus, Mars, Jupiter, Saturn
Comparing Planets and Stars

Feature     Planet            Star

Location    In solar system   Far outside of
            (fairly near)     solar system
                              (very far)
Real size   Smaller than      Larger than
            stars             planets
Why do we   Reflects light    Gives off its
see it?     from the Sun      own light
Comparing Planets and Stars cont

Feature      Planet           Star

Surface     Usually cool or   Very hot
temperature cold
Made of      Rocks or gases   Gases under
                              pressure
You see      Wanders through Part of a
             constellations  constellation
The Planets & Other
Objects in the Solar System

        4.5 and 4.7

Images from NASA - http://pds.jpl.nasa.gov/planets/welcome.htm
Our solar system
is made up of the
   Sun and the 9 planets (with their moons)
    1.   Mercury
    2.   Venus
    3.   Earth
    4.   Mars
    5.   Jupiter
    6.   Saturn
    7.   Uranus
    8.   Neptune
    9.   Pluto
The Planets

   Rotate                      Gravitational pull
    – 1/day for Earth            – based on mass
   Revolve around               – Compared to Earth
    (orbit) the Sun           Inner  planets
    – Orbital period time     close to the Sun
      to go around the Sun    Outer  planets far
      called Year
                               from the Sun
Inner Planets

 Planets that are close to the Sun
 Also called the terrestrial planets (like
  Earth)
 Mercury
 Venus
 Earth
 Mars
Outer Planets

 Planets that are far from the Sun
 Also called the gas giants
 Jupiter
 Saturn
 Uranus
 Neptune
 Pluto
www.star.le.ac.uk/edu/ planets/sun.html
Other Objects in the Solar
System
 Satellites objects that revolve around
  the planets
 Earth
    – Has one moon
    – Visited 6 times between 1969 and 1972
Planets and their Moons
    Planet    Number of Moons
    Mercury   0
    Venus     0
    Earth     1
    Mars      2
    Jupiter   39
Planets and their Moons cont
    Planet    Number of Moons
    Saturn    30
    Uranus    20
    Neptune   8
    Pluto     1
Asteroid

            Small rocky objects
            Revolve around the
             Sun
            Not considered
             planets
Meteoroid

 lump of rock or metal pulled through
  Earth’s atmosphere
 rubs the air as it falls making heat
 it burns up showing a bright streak in
  the sky
 called a meteor or shooting star as it
  burns up
 called a meteorite if it hits the Earth
Comet
 chunk of frozen water and dust
 travels in a long orbit around the Sun
 melts to liquid then gas vapour when
  near the Sun
 water and dust vapour can be visible for
  months
 Ex. Halley’s comet seen in 1986 and not
  again for 76 years
Halley’s Comet
The orbit of Halley’s Comet
4.8 Telescopes

 The universe comprises everything that
  exists everywhere.
 We could see 5 planets with the naked
  eye but Galileo’s telescope, a new
  technology expanded the boundaries of
  astronomy.
 The main purpose of a telescope is to
  gather light.
Galileo improved on the telescope.

 It was Galileo who made the instrument
  famous.
 He constructed his first three-powered
  spyglass in June or July 1609, presented an
  eight-powered instrument to theVenetian
  Senate in August.
 Turned a twenty-powered instrument to the
  heavens in October or November.
 With this instrument he observed the Moon,
  discovered four satellites of Jupiter, and
  resolved nebular patches into stars.
Two Basic Designs of the Telescope.

 Galileo’s design is called the refracting
  telescope and is still the basic design of
  smaller telescopes.
 It uses lenses. They can only be up to one
  meter in diameter.
 Newton, in 1668 designed a reflecting
  telescope.
 It uses a mirror and has no limitations so all
  larger telescopes are made this way. See
  p210 figure 1
Both types of telescopes.
Improvements

 Adding a camera that can be
  programmed to gather light over an
  extended period of time. See page 210
  figure 2.
 Placing a telescope in orbit.
The Hubble Telescope
Sent in orbit in 1990.
 Named after Edwin
  Hubble 1889 – 1953
 Two major
  advantages
    – No light pollution
    – No air pollution
   It has been
    constantly upgraded
    with new technology.
Hubble Deep Field
  - Aimed at a dark patch in the sky.
  - Camera was on for 100 hours.
How we look back into time.
4.6 Planets and Retrograde Motion

 Because the Earth is not the centre of
  the Solar system, Planets, as seen from
  the Earth, seem to go backwards
  sometimes. This is called retrograde
  motion.
 Check out the youtube video called
  “Retrograde motion and the opposition
  of Mars”.
4.10 Case Study. An Important Star.
•   The most important star is our Sun.
•   It is the closest star and give off
    tremendous amounts of heat and light
    energy.
    - It provides all of the energy for plants
    and animals.
    - It’s gravitational force keeps us in our
    orbit.
Process of producing the Energy.

 Energy is provided by nuclear explosions.
 The process of nuclear fusion occurs in the
  core.
 This process through nuclear explosions
  provides all of the energy.
 Every second the sun makes more energy
  than has been used by people through out
  history.
   Do Handout on 4.10 p 215
4.11 p218 Galaxies and Star Clusters

 Galaxy: A galaxy is a huge collection of gas, dust,
  and hundreds of billions of stars.
 All of the stars are attracted to each other by the
  force of gravity and are always in motion.
 Our solar system is part of the Milky Way Galaxy.
 The Milky Way is the combined light of 400 billion
  stars in our galaxy.
 The Milky Way is disk shaped with our sun near the
  outer part of the disk.
 The Milky Way is a spiral galaxy.
 See pictures p 218 figure 1 and figure 2.
Types of Galaxies

 Three types
 Spiral Galaxies
 Elliptical Galaxies
 Irregular Galaxies    see p219 figure 2,
  3, 4, 5
Unusual Galaxies

   The further we see the more discoveries
    we make.
    – Some galaxies appear to be colliding,
      recombining, and tearing away stars from
      one another.
    – Smaller galaxies are “eaten” by larger ones
    – Quasars are very distant objects that look
      like faint stars but give off up to 100 times
      more energy than the Milky Way galaxy.
Star Clusters

 Groups of stars that are close together
  and that travel together are called star
  clusters.
 A single cluster can have from 10 to a
  million stars.
 Clusters are part of galaxies.
 Eg. Pleiades, from the constellation of
  Taurus.
4.13 Evidence of an Expanding Universe
 The waves in front of a duck swimming
  towards you are closer together than the
  waves at the back of a duck swimming away
  from you. See p222 fig 1, 2.
 The visible spectrum is made up of the
  colours red, orange, yellow, green, blue,
  violet. (ROYGBIV)
 Red has the longest wavelength and violet
  has the shortest wavelength.
 The light from a galaxy can be divided into its
  lines of colours or wavelength to produce a
  spectrum.
Red Shift and Blue Shift
   Edwin Hubble discovered that
    – Light from a galaxy moving away from us is shifted
      towards the longer wavelengths of red. A red
      shifted spectrum means the galaxy is moving
      away from us.
    – Light from a galaxy moving towards us is shifted
      towards the shorter wavelengths of blue. A blue
      shifted spectrum means the galaxy is moving
      towards us. Oh no!
    – Most galaxies are red shifted which means they
      are moving away from us which indicates an
      expanding universe.
4.15 The Origin of the Universe
 Cosmology is the study of the origin and
  changes of the universe.
 The Big Bang Theory
    – If the universe is expanding, then all of the
      material in the Universe must have come from the
      same location at time zero.
    – This was between 10 to 15 billion years ago.
    – All matter of the entire universe was packed into
      one small, extremely dense, hot mass under
      enormous pressure.
Support for the Big Bang Theory

 Red Shift
 Back ground radiation.
    – a sufficiently sensitive radio telescope
      shows a faint background glow, almost
      exactly the same in all directions, that is
      not associated with any star, galaxy, or
      other object.
   Scientist know what the universe was
    likely like a millionth of a second after
    the big bang, but what did it look like a
    millionth of a second before the big
    bang?
The origin of the Solar System

 All stars are made from a spinning mass
  of gas and dust which is called a
  nebula.
 Gravity causes the matter of the nebula
  to spin together. The centre becomes
  the sun. If conditions are right other
  objects can be formed. See p 227 fig 3

								
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