Science Glossary Terms 7

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Science Glossary Terms 7
2012-12-19 00:34:07
astrology science ms day

Glossary terms for chapter 7 of ON Science 9
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  1. Celestial object
    Any object that exists in space such as a planet, moon or star. (Earth.)
  2. Astronomer
    A scientist who studies astronomy.
  3. Revolution
    The time it takes for an object to orbit another object; Earth's revolution around the Sun takes 365.24 days.
  4. Rotation
    The turning of an object around an imaginary axis running through it; Earth's rotation around its axis is 24h.
  5. Constellation
    A group of stars that form a distinctive pattern in the sky. (Orion, Leo.)
  6. Light-year
    The distance that light travels in one year, about 9.5 x 1012 km.
  7. Apparent magnitude
    The brightness of a star as seen from Earth.
  8. Asterism
    A smaller group of stars that form a pattern within a constellation.
  9. Pointer stars
    Stars which are used to find an area of the sky.
  10. Tides
    The rising and falling of oceans water caused by the Moon's and Earth's gravity.
  11. Phases of the moon
    The monthly progression of changes in the appearance of the Moon that results from different portions of the Moon's sunlit side being visible from Earth.
  12. Lunar eclipse
    The phenomenon in which the full Moon passes into Earth's shadow.
  13. Solar eclipse
    The phenomenon in which the shadow of the Moon falls on the Earth's surface.
  14. Why do we have seasons?
    The earth is on a tilt and when it is summer the Northern Hemisphere is tilted towards the Sun and when its winter the Northern Hemisphere is tilted away from the sun.
  15. Planet
    • An object that orbits one or more stars (and is not a star itself), is spherical, and does not share its orbit with another object.
    • Inner- Mercury, Venus, Earth, Mars.
    • Outer- Jupiter, Saturn, Uranus, Neptune.
  16. Solar System
    • A group of planets that circle one or more stars.
  17. Retrograde motion
    The movement of an object in the sky, usually a planet, from east to west, rather than its normal motion from west to east this effect is generally produced when Earth is passing the planet in its orbit.
  18. Astronomical unit
    • The average distance between Earth and the Sun. 150 x 106
    • km.
  19. Orbital radius
    The average distance between the Sun and an object that is orbiting the sun.
  20. Geocentric model
    A model of the solar system stating that Earth is the centre of all planetary motion, with the planets and the Sun traveling in perfect circles around Earth.
  21. Heliocentric model
    A model of the solar system in which the Sun is the centre with the planets orbiting it.
  22. Comet
    An object composed of rocky material, ices, and gasl comes from the Kuiper belt or Oort cloud.
  23. Asteroid
    An object in space that ranges in size from a tiny speck, like a grain of sand, to 500 km wide most asteroids originate in the asteroid belt between Mars and Jupiter.
  24. Meteoroid
    A piece of rock moving through space
  25. Meteor
    A meteoroid that hits Earth's atmosphere and burns up.
  26. Meteorite
    A meteoroid that is large enough to pass through Earth's atmosphere and reach the ground, without being totally burned up.
  27. Trans-Neptunian object
    An object that circles the Sun beyond the orbit of Neptune.