SNC1DW Chapter 8

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SNC1DW Chapter 8
2014-02-27 19:27:47
science space sun stars

Glossary terms and definitions for chapter 8.
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  1. Electromagnetic Radiation
    Varying types of electromagnetic waves, from radio waves to gamma rays. All waves travel at the speed of light.

  2. Refracting telescope
    A telescope that uses a lens to collect the light from an object.

  3. Reflecting telescope
    A telescope that uses a mirror to collect the light from an object. 

  4. Satellite
    An artificial object/vehicle that orbits a celestial body. Can also be a celestial body that orbits another of a larger size.

    E.g. The Moon, The Hubble Space Telescope
  5. Orbiters
    Observatories that orbit other planets. Usually made to take high-resolution pictures not obtainable from Earth.

  6. Solar nebula theory
    The theory that describes how planets and stars formed from spinning, contracting disks of dust and gas.

  7. Star
    A celestial body made of super-heated hydrogen and helium.

  8. Nebula
    A giant cloud of gas and dust, which could be the birthplace of most, if not all, celestial bodies.

  9. Protostar
    The hot, condensed object at the center of a nebula.

  10. Nuclear fusion
    The process where hydrogen nuclei fuse to form helium nuclei. This is also a process of energy production.

  11. Photosphere
    The Sun's surface layer.

  12. Sunspot
    Area of strong magnetic fields on the photosphere.

  13. Solar wind
    Streams of fast-moving charged particles released by the Sun into the solar system.

  14. Solar flare
    Fast-moving charged particles released from the Sun that collide with Earth's or another celestial body's atmosphere.

  15. Importance of the Sun
    • The Sun:
    • -is needed for all life on Earth
    • -drives most processes on Earth
    • -powers the winds and ocean currents
    • -provides photosynthesis

  16. Luminosity
    The measure of the total amount of energy a star radiates per second. Measured in Joules/second.

    E.g. Astronomers have found stars from 10 000 times less luminous than the Sun, to over 30 000 times more luminous.
  17. Absolute magnitude
    A star's magnitude as seen 32.6 light-years from Earth.

  18. Spectroscope
    An instrument that produces a spectrum from a narrow beam of light, and projects it onto a photographic plate/digital detector.

  19. Spectral lines
    Certain wavelengths in a spectrum identified by lines. Spectral lines identify chemical elements.

  20. Hertzsprung-Russell (H-R) diagram
    A graph that compares the properties of stars.

  21. Main sequence
    A band of stars on the H-R diagram that runs diagonally from the top-left to the bottom-right. 90 percent of stars are in the main sequence.

  22. White dwarf
    A small, dim, yet very hot star.

  23. Supernova
    A giant explosion where the entire outer parts of a star get blown off.

  24. Neutron star
    A star so dense that only neutrons exist in it's core.

  25. How low-mass stars evolve
    Nebula -> small protostar -> red dwarf -> red main sequence star -> white dwarf. Low mass stars stay as main sequence stars for as long as 100 billion years. When they run out of hydrogen, they become white dwarfs.

  26. How intermediate-mass stars evolve
    Nebula -> medium protostar ->  yellow main sequence star -> red giant -> white dwarf. Intermediate-mass stars burn their hydrogen faster than low-mass stars, so they only last about 10 billion years. When their hydrogen runs out, they become red giants and eventually white dwarfs.

  27. How high-mass stars evolve
    Nebula -> large protostar -> blue main sequence star -> red supergiant -> supernova -> neutron star or black hole. High-mass stars burn their hydrogen the fastest, so they die more quickly and violently. Heavier elements form by fusion, and the star expands into a supergiant. When the star explodes during a supernova, it becomes either a neutron star or a black hole.

  28. Black hole
    The result of the deaths of stars over 25 solar masses. The remnants of the supernova is crushed by gravity and nothing can escape it, not even light.