astronomy unit 1 test

terms and study materials for descriptive astronomy exam 1.

astronomial unit

distance between the earth and the sun.

lightyear

distance light travels to earth in one year.

rotation

spin on axis, ex: 24 hrs for earth

revolution

going around something, ex: 365 ¼ for earth

polaris

the north star alligned with earth’s axis. three fists up from the horizon.

ecliptic

path the sun takes, rising in the east and setting in the west.

earth’s tilt

23 ½ degrees

what determines earth’s seasons?

earth’s tilt

constellation

NOT a pattern. A region in the sky, in which everything in range is apart of that specific constellation. ex: draco, ursa major, etc…

astertism

the shape/pattern of the stars. ex: big dipper

zenith

straight up

kepler’s 1st law

eliptical orbits, planetary motion, orbits are eccentric.

kepler’s second law

every planet is “attracted” to the sun

perihelion

when earth is closest to the sun. ex: winter

aphelion

when earth is farthest away from the sun. ex: summer

precession

slow movement of the earth in which the direction of earth changes.

moon movement

same side always faces us. rotation and revolution takes one month. (moonth!)

solar eclipse

when the sun is blocked by the moon

lunar eclipse

when the moon goes into earth’s shadow. aka “blood moon”

perigee

when the moon is closest to earth

apogee

when the moon is farthest from the earth