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