Introduction Flashcards
1 Parsec =
3.262 Light Years
1 Astronomical Unit (AU) =
Average distance between sun and earth
1 Light Year =
64,300 AU
Satellite
A body orbiting a larger body
Radius of visible universe
14 billion parsecs
4 Fundamental forces of nature
Gravitation, electromagnetic force, strong interaction, weak interaction
Zenith
highest pint an object reaches in the sky before it comes back down
Nadir
Closest point to the horizon an object gets before going up again.
How many constellations?
88, they map the sky
Celestial sphere
Half dome above the earth that we picture the stars sitting on
Horizon
Where the sky meets the ground
Constellations
Fixed patterns of stars on the celestial sphere
Celestial poles
Lie directly above the north and south poles, don’t move
Celestial equator
Lies directly above earth’s equator
Ecliptic
The line that the sun traces across the celestial sphere
Angular separation between stars
60 min in 1 degree, 60 sec in 1 min
Right Ascension
Stated in hours (24 hrs), matches longitude
Declination
Stated in degrees, matches longitude, ranges from -90 to 90
Summer Solstice
June, longest day of the year
Vernal Equinox
March, Same day and night times
Winter Solstice
December, Shortest day of the year
Auturnal Equinox
September, Same day and night times
When is it summer?
When we are tilted toward the sun, direct sun beam hits
When is it winter?
When we are tilted away from the sun, sun beam has to spread out, less energy
Earth’s Tilt
23.5 degrees
Scientific Method
Observation, Hypothesis, Experiment, Theory
3 Criteria of a Theory
Fit the available observed data, make predictions that allow it to be tested, and represent nature in the simplest way (Aesthetic)
