Chapter 16 Earth and Moon Flashcards
Define time and describe location on the surface
Causes season
Earth’s Movement
Yearly revolution about the sun
Daily rotation about its axis
Clockwise wobble of its rotation axis
Motion of Earth
Not circular
2.5 million km closer in January
2.5 million km more distant in July
Earth receive about 6% more solar energy in January
Elliptical orbit
Earth’s rotation axis inclined at…
23.5 degrees
Line on celestial sphere above earth’s equator
Celestial Equator
Pendulum oscillates in fixed direction
Orientation changes as earth rotates
Foucault pendulum
Deflection of path as earth rotates beneath moving objects
Coriolis effect
Changes direction of rotation axis on celestial sphere
Reaction of earth to gravitation pull on its equatorial bulge by the moon and sun
Precession
Intersection of two straight lines
Won’t work for earth’s curved surface
Identifying place
Position on flat surface
Intersection of parallels and meridians defined with respect to rotation axis
Parallels: Latitude
Meridians: longitude
Identifying place
Position on earth
Time standards depend on measuring…
Intervals between evenly spaced periodic events
Viewed from above North Pole
Earth revolves counterclockwise about the sun and rotates in the same direction
Sun rises in the east and sets in the West
Earth_Sun Motion ( daily time)
Time at which the sun is at the celestial meridian
“Noon”
Given by position of sun in the sky
Can be measures with gnomon or sundial
Apparent local star
Time averaged from apparent solar time
Mean solar time
