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					Earth and Space
  FSS Gr. 9 Science - Davies
Mercury   Venus              Earth         Mars

    The four inner planets
                  terrestrial …rocks and minerals
The outer planets

                                           and tiny

                       four gas giants …

             Jupiter    Saturn   Uranus Neptune
m   vem   j   s   u   n   p
Planets and moons are nonluminous:
 they do not give off their own light;
 we see them when light from the Sun reflects
 off them; planets are usually rocks or gases;
 planets do not twinkle.

Stars emit huge amounts of energy; they are
 usually larger than planets, and are gases
 under high pressure and temperature;
 stars twinkle.
Our Solar System

•The Sun is a star at the centre of our solar system
•The planets revolve around the sun in paths
 called orbits
•The time taken for one revolution around the sun
 is called one orbital period – 365 days for Earth
•Each planet rotates on its axis; Earth rotates once
 around its axis every 24 hours.
                             Orbital periods

 225d   687d                                   248 a
m     vem      j      s            u      n      p
88d   365d     12 a   30 a        84 a   165 a
Sending unpiloted Probes to planets and moons
1959 probes photographed far side of Moon
1977 Voyager 2 to study Jupiter, Saturn,
      Uranus, and Neptune; continue to future
1989 Magellan mapped Venus
1989 Galileo travelled past asteroids, and
      explored Jupiter and its moons
1996 Pathfinder landed on Mars, and sent robotic
      rover Sojourner to explore surface
1997 Cassini studied Saturn (continue to 2008)
1998 Mars Surveyor ’98 to study climate
      on and search for water on Mars
The sun is the star at centre of our solar system;
            about 5 billion years old;

                     1 Astronomical Unit

                        145 million km

Our Sun
The Sun contains 99.9% of the mass of the solar syste
     Nuclear fusion in core: 15 million degrees C;
            Power: 383 billion trillion kW
Corona: hot outer part:
about 1 million degrees C


            Solar prominences:
            Glowing gases as high as 400 000 km
            a huge cooler area
A sunspot
           Very small, closest to Sun;
no atmosphere - very hot days, very cold nights;
 has magnetic field - iron core and rocky crust;
     craters caused by collision with rocks.

Bright - known as both ‘evening star’ and ‘morning star’
   scorching surface temperatures – could melt lead;
atmosphere of carbon dioxide, with sulfuric acid clouds.
    Tilted axis of rotation – produces 4 seasons;
      molten nickel-iron core – magnetic field;
 atmosphere of nitrogen, oxygen, and water vapour
   protects from UV radiation, and from meteors;
         oceans cover over 70% of surface;
active volcanoes and earthquakes – dynamic planet.
           The Red planet – rusty soil;
 evidence once had volcanoes, glaciers, and water;
atmosphere too thin, and too cold for water to exist;
            no signs of life found yet.

•About 4,000 asteroids circle the Sun in the large
 gap between the orbits of Mars and Jupiter;
•Asteroids are rocky and metallic objects that are
 too small to be considered planets;
•The largest asteroid is about 1000 km in
•They are material left over from the formation
 of the solar system;
•Earth has been hit by asteroids in the past.
•Largest planet, composed of hydrogen and helium;
  •Atmosphere contains ammonia ice, ice or water;
•Strong magnetic field; persistent lightning storms;
 •Has 16 moons, and a thin three-band ring system;
              •Moon Io has iron core;
•Moon Europa may have water beneath ice surface.
A giant gaseous planet with high-speed jet streams;
Atmosphere mostly hydrogen and helium; storms;
 Magnetic field 1,000 times stronger than Earth’s;
Seven rings, may be remnants of moons or comets;
                 Over 18 moons;
 Largest moon, Titan, has atmosphere of nitrogen.


Spins on axis in plane of orbit – extreme seasons;
Atomosphere of hydrogen, helium, and methane;
    Strong winds; dark rings and 15 moons.
 Strongest winds on any planet – 2,000 km/h;
4 rings and 8 moons; the largest moon, Triton,
     has volcanoes that spew nitrogen gas.
Smaller than our moon; farthest away from Sun, little known;
 Orbit is elliptical – surface depends on distance from Sun;

       Recently ‘demoted’ – not considered a planet,
              one of numerous similar debris

                         poor pluto
         Irregularly shaped nucleus of ice, carbon,
                Silicon, methane, ammonia;
     These substances boil as comets get close to Sun,
A ‘tail’ of gases and dust particles is pushed by solar wind

                Small bodies - comets

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