ASTR 1,2,3

• define space: everything about earth's atmosphere
• astronomy is 1 of 2 first sciences
• what was earth according to Hinduism:

  • earth is flat
  • sky is a big dome
• how long is the milky way?


  925,000,000,000,000,000 km
• what was earth according to the bible & ancient greece:

  • space is a big ocean
  • theres 2 heavens (ocean of heaven & heaven of heaven)
  • theres an underworld
  • theres 2 pillars (pillars of earth & pillars of sun + stars)
• the universe was the first creation
• the universe was seen as an eternal universe, this meant = no end or no start.

  later on this was proven to be false, the universe was created from the big bang
• 10^3 = 1000 = kilo

  10^6 = 1,000,000 = mega

  10^9 = 1,000,000,000 = giga

  10^12 = 1,000,000,000,000 = tera

  10^-3 = 0.001 = milli

  10^-6 = 0.000001 = micro

  10^-9 = 0.000000001 = nano

  10^-12 = 0.000000000001 = pico
• The scales of the universe start from:

  10^-15 and work up to 10^25
• what have astronomers discovered in our universe?

  • planets
  • asteroids
  • stars
  • comets
  • nebula
  • galaxies
  • clusters of galaxies
  • intergalactic gas
• the night sky: from 5,000 to 10,000 stars can be seen by the naked eye, however not all stars are bright enough to see them all (half in northern and half in southern)
• define city light: sky reflecting back
• city lights is the reason we can only see the brightest stars
• without a telescope, we cannot see the details of the stars
• define constellation: populated groups of stars, normally by Greek + Roman Heroes + Monsters. (also called regions)
• what is polaris?

  North Star
• how many regions/constellations are there?

  88
• what are the common guides used for finding constellations?

  • using the Big Dipper as guide
  • using the winter triangle
  • using the summer triangle
• what stars are in the brightest stars in winter triangle:

  • procyon
  • betelgeuse
  • sirius
• what are the 2 changes in the sky?

  1. day & night (24hrs)
  2. seasons (365 days)
• the 3 apparent cyclic motions of suns and stars are due to motions of EARTH:

  1. Rotation (day & night)
  2. Revolution (seasons)
  3. Precessions (complete motion of earth, takes 26,000 years)
• the star tracks from the north equator go in this direction: up & down
• the star tracks from the equator go in this direction: left & right
• the star tracks from the middle latitude go in this direction: angular up & angular down
• what device is used to understand the star tracks?

  Foucault Pendulum
• define geographical coordinates: latitude + longitude, meridians & parallels
• Longitude starts at the prime meridian going left and right (west and east), and is measured in degrees starting from 0° to 180°
• latitude begins from the equator going up and down (north and south), and is measured in degrees starting from 0° to 90°
• what is the latitude of the north pole?

  90° N
• what is the latitude of the south pole?

  -90° S
• what does noon mean to local time?

  12pm
• what does noon mean astronomical?

  highest peak of the sun
• sun rises from west to east
• time zones were introduced for convenience as travel times shrunk

  • W -> E = -1 hour for each meridian
  • E -> W = +1 hour for each meridian
• what is the international date line?

  an imaginary line on earth that separates 2 consecutive calendar days
• why is the international date line no straight?

  to avoid confusion in land masses
• for the international date line:

  • going east to west = lose a day
  • going from west to east = gain a day
• who is Sir Sandford Fleming?

  canadian engineer + inventor, proposed worldwide standard time zones
• what is the celestial sphere?


  an imaginary sphere surrounding the earth where all objects in the sky can be located
• celestial coordinations of the moon changes