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45 Cards in this Set

  • Front
  • Back
Scientific Notation
-Needed for astronomical numbers
-dicimal number btw 1 and 10 multiplied by 10^n
Figures astronomers have chosed to remember the night sky
Winter Soltice
Ecliptic is farthest south of the celestial equator and when the Sun appears at that point each year (Dec. 21)
Summer Soltice
Ecliptic is farthest north of the celestial equator and when the Sun appears at that point each year (June 21)
East-West distance
Circumpolar Stars
Star that always remains above the horizon
Measure of how much an ellipse deviates from a perfect circle
Product of an object's mass and velocity
Point at which an object orbiting the Earth is nearest to the Earth
Potential Energy
stored energy for later conversion into kinetic energy
Distance between adjaacent peaks (or troughs) of a wave
Light Year
Distance that light can travel in one year
Sun's apparent annual path among the constellations
Vernal/Spring Equinox
Point in Pices- Ecliptic crosses the celestial equator (Mar. 21)
Autumnal Equinox
Point in Virgo - Ecliptic crosses the celestial equator (Sept. 21)
Right Ascension
Angular east-west distance btw the vernal equinox and a location on the celestial sphere
Kepler's first law
Orbit of each planet around Sun is an ellipse with the Sun at one focus
Kepler's Second law
A planet moves faster when it is closer to the sun, slower when it is far
Kepler's third law
P^2=A^3 Orbital period related to semi-major axis
Semi-major axis
Half of an elipse long axis, A
-First true person of Modern Science
-First observations w/telescope
-Objects fall at same rate, regardless of mass
anything that can cause a change in momentum
point at which an object orbiting the Sun is farthest from the Sun
angular momentum
angular momentum of an object moving in a circle or radius r is the product of
m x v x r (mass speed distance)
detailed geometry of geometric universe
Prehistoric culture (myan)
celestial sphere
imaginary sphere on which objects in the sky appear to reside when observed from earth
Up and down- 0 degree= equator
N/S distance btw the celestial equator and a location on the celestial sphere
Retrograde Motion
(see diagram) backward mmotion. mars is in retrograde druing periods when it move westward rather than eastward realative to the stars
type of oval that happens to be the shape of orbits - (tack and string demo)
Astronomical unit
average distance of earth from sun
(150 million km)
Newton's 1st law
All objects mmove in a straight line or are at rest unless acted by force (inertia)
newton's 2nd law
apply a force, it has momentum. to change momentum, have to apply another force
newton's 3rd law
every action has an opposite and equal reation.
rate at which an object's velocity changes
Kinetic Energy
energy of motion
Cosmic Calendar
all cosmic time compressed into single year (we are in the last few seconds)
Night sky
"hollow globe" -
zenith (N)/nadir( S)
altitude, azimuth
Siderial Day
23h 56min, btw sucessive appearances of any particular star on the meridian (true rotation period of earth around sun)
solar day
24 hours, which is the average time btw appearances of the Sun on the meridian
NOT result of change in earths distance from sun - change from direct to to indirect sunlight
lunar eclipse
moon in earths shadow
solar eclipse
moon's shadow falls on oart of earth
Tycho Brahe
used sighting instruments and no telescope