Astronomy Week 1 - 2

light year

distance that light travels within a year

constellations

the patch of sky or sector that gets the name rather than the set of stars themselves

asterism

a subset of stars that form a widely recognized shape (Ex. the Big Dipper)

The Celestial Sphere

a simplified scientific model of the sky that assumes all the stars, no matter how far they are, are projected onto a sphere around the earth

horizon

where the dome of the sky you can see, meets the ground from your point of view

zenith

the point directly above your head

nadir

the point directly below your feet

celestial equator

the projection of the earths equator into space

north celestial pole

the projection of the earths geographic north pole into space

south celestial pole

the projection of the earths geographic south pole into space

star motions

in the celestial sphere model, we pretend that the earth is fixed and that the stars are moving around the sky

North Star

polaris

astrology

a psuedoscience that has roots in astronomical observations. the astrological signs represent the constellations that the sun “appears” in throughout the year

archeostronomy

ancient astrology in short

retrograde motion

some of the known planets seem to move backward through the sky and it occurs when we “catch up and pass” a slower planet