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43 Cards in this Set

  • Front
  • Back
A: The North Star
A: The end of the handle of the little dipper
A: All the stars that never set at a given latitude; all the stars between Polaris and the northern horizon.
Circumpolar stars at the Nort Pole move how? Are there circumpolar stars at the equator?
A: move horitzontally
A: no
Explain the daily motions due to the motions of the earth.
A: earth's rotation causes day and night because it makes the sun appear to follow a diurnal path across the sky
A: Causes constillations and stars to appear to rise in the east and set in the west
Explain annual motions due to the motion of the earth.
A: the earths revolution around sun--orbit (revolution)
A: takes approx 364 1/4 days
A: different constellations are visible at night during different times of the year.
A: every star rises approx 4 minutes earlier each night than it did the night before
What is the difference between rotation and revolution?
A: rotation spins around its own axis while revolution spins around another object
A: a configuration of stars often named after an object, a person, or animal

A: know figures 1-2, 1-3 and 1-4
A: A band of 13 constellations around the sky through which the Sun appears to move throughout the year.
A: The annual path of the sun on the celestial sphere; the plane of the earths orbit around the sun.
Name and define the four (4) phases of the moon.
A: Quarter Moon--see only half of the moon; high in the sky at sunset; sets at midnight and rises at noon
A: Full Moon--see whole moon (opposite the sun); rises when the sun sets and high in the sky at midnight
A: New Moon--see no moon at all
A: Eclipse--when moon is in shadow of sun
Total Eclipse
A: moon in its entirity is blocked from sun
Partial Eclipse
A: only part of the moon is blocked by the earth
Annular Eclipse
A: a ring of the sun around the moon-happens because sun is to far away in orbit for moon to block it out in entirity.
Solar Eclipse
block sunlight from getting to the earth; the moon gets in the way; if you are outside the shadow, you don't see the total eclipse
Lunar Eclipse
A: the sun, moon, and earth are all lined up with one another
Why don't eclipses happen every month?
A: because of the 5 degree tilt of the moon
What did the Babylonians contribue to the history of astronomy?
A: provided observations for the Greeks
What did the Greeks contribute to the History of Astronomy?
A: Ptolemy wrote book Almagest
A: provided a geocentric (earth centerd) model of the universe
A: discovered by Copernicus
A: a sun-centered solar system
What is significant about Tycho Brahe?
A: he was the last astronomer without a telescope.
A: he provided Kepler with the data needed in order to develop his three laws.
What are Keplers Three (3) Laws of planitary motion?
A: 1) The orbit of a planet is in the shape of an elipse with the sun at a focus.
A: 2) A line joining a planet and the sun sweeps out equal areas in equal times.
A: 3) The square of a planet's sidercal period around the sun is directly proportional to the cube of the length of its orbits "semimajor axis".
Galileo and his telescope observations.
A: used a telescope and challenged the conventional wisdom of the motion of objects and the nature of the heavens.
A: Phases of Venus (shows Venus orbits around the sun) and moons of Jupiter (shows Jupiters moons orbit around it not earth)
What are Newtons Three Laws of Motion?
A: 1) a body remains at rest or moves in a straight line at constant speed unless acted upon by an unbalanced outside force.
A: 2) force=mass x acceleration
A: 3) whenver one body exerts a force on a second body, the second body exerts an equal and opposite force on the first body.
**first two laws apply only to single objects**
Define Newton's universal law of Gravity.
A: Two bodies attract each other with a force that is inversely proportional to the square of the distance between them.
A: F=G m1m2/r2
Describe the wave nature of light.
A: White light-the composite made up of different colors of light
A: Red light- longest wavelength
A: Blue light- shortest wavelenth
Electromagnetic Waves
A: Einstein showed that light sometimes behaves as particles and sometimes as waves.
Name different wavelengths, longest to shortest.
A:longest--Radio, infared, visible, ultraviolet, x-ray, gamma-ray
Continous Spectrum
Emission line Spectrum
A: A spectrum that contains only bright emission lines.
Absorption Line Spectrum
A: dark lines superimposed on a continuous spectrum
Describe Kirchhoff's three (3) Laws.
A: 1) You can tell temperature of object by color it emits.
A: 2) Emission lines from low density gass tell chemical composition.
A: 3) Absorption lines show chemical composition of cool lights absorbing the light.
The Doppler Effect
A: the amount the pitch changes is dependant on how fast the object is moving.
A: Objects moving toward you emit a blue light and those moving away, red.
A: Doesn't work sideways motion, only "radial velocity" (towards/away)
How does temperature effect light?
A: As an object heats up, it gets brighter because it emits more electromagnetic radiation.
A: The dominant color or wavelength of the emitted radiation changes with temperature. (Cool object emits long wavelengths, hot emits shorter wlengths)
How is chemical composition used in light?
A: each chemical element has its own unique pattern of spectra lines so chemical composition is determined by the lines in the spectrum.
Radial Velocity
A: The speed determinded from the Doppler shift because the motion is along our line of sight or along hte "radius" drawn from Earth to the star.
What are the reasons for optical telescopes?
A: 1) light gathering (see fainter objects)
A: 2) Resolution (making a telescope bigger improves resolving power-angular resolution)--limited by atmosphere
A: 3) Magnification
Refractor Telescopes
A: lens based; chromatic abberation; used by Galileo
Reflector Telescope
A: mirror based; spherical aberration-true shape should be parabolic; developed by Newton
What are some atmosperic effects of telescopes?
A: seeing only transparent to visible and radio waves; limits angular resolution in practice
Radio Telescopes
A:Use a techinique like reflectors to focus radiowaves (like a mirror based optical telescope)
What are two examples of Radio Telescopes?
A: Arecibo-largest radio telescope
A: (VLA) Very Large Array- uses interferometry to improve angular resolution
Angular Resolution
A: let's you see in more detail; limited by the atmostphere
What is Retrograde Motion and why does it take place?
A: against the normal motion because the earth moves around the sun more rapidly
A: as it moves along, it appears to stop, go backwards, then forwards again