motions of earth, moon and sun. i.motions movements
TRANSCRIPT
MOTIONS OF
EARTH, MOON
AND SUN
I. Motions
• movements
1. APPARENT MOTION
• Motion that an object appears to make
2. Daily motion and stars:
• Paths of all stars appear to be ______ or parts of a _____ called an ___.
• Rise in the _____ and set in the _____• Motion occurs at rate of ___________
(360 in 24 hours)• ______ remains stationary in the
center .
circularcircle arc
East West15o per hour
Polaris
**this apparent motion is because the Earth ROTATES!
Sta
r M
otio
n a
t M
idd
le
Lat
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des
3. Apparent Motions of Earth’s Moon:
• Same motion as the stars: rises in the ____ and sets in the _____.East West
4. Apparent motions of the Sun:
• Path from sunrise to sunset has the shape of an ___.
• Path changes in two ways throughout the seasons:1. Length2. Position in the sky
• Reaches highest point in sky at this time of day: __________.
arc
Solar Noon
• Can only be directly overhead (90) between ______ and ______.– Is the Sun ever directly overhead in
New York State?
23.5oN 23.5oS
NEVER!!
II. Models that Explain Apparent Celestial Motions:
1. Geocentric model:Earth doesn't move
and most celestial objects revolve around it
2. Heliocentric Model– _____ is at center of solar system– Earth ________ on its axis and
_________ around Sun.– Moon _______ on its
axis and _________around Earth.
Sunrotates
revolvesrotates
revolves
• Which of the two models do we believe today?
HELIOCENTRIC MODEL
• Moves with our galaxy, called the _________ as the Universe is _________.
• ____________ revolves around center of Milky Way (it takes ____ million yrs.)
• _______ on its axis and _______ around Sun in an orbit, whose shape is an ______.
IV. Actual Earth Motions
Milky WayexpandingSolar System
225Rotates revolves
ellipse
1. Rotation of Earth• Earth spins on its ______.• Its’ axis is tilted at _____.• Earth rotates at a rate of ____________.
axis23.5°
15° per hour
A. Evidence of Earth’s rotation
1. Foucault pendulum
A. Evidence of Earth’s rotation (ctd)
2. Coriolis effect– All objects moving at Earth’s surface are
____________________________________.– Deflection appears to the ______ in the Northern
Hemisphereright
deflected from a straight line path
2. Revolution of the Earth
• Revolves around sun in a slightly ________ orbit.
• Revolves at a rate of about ___________.– How many degrees in a circle?– How many days in a year?
elliptical
1o per day360o
365 days
360o
365 days
A. Evidence of Earth’s revolution around the Sun:
1. Different ___________ are visible during different times of the ____.
2. Apparent size of ____ changes as earth is ______ or ______ away
constellationsyear
Suncloser further
3. Earth Motions and Time
• Time is based on Earth’s _______ on its axis.
• ALL PLACES ON THE SAME LINE OF ____________ HAVE THE SAME TIME
• Time zones:–keep time the same for regions
rotation
LONGITUDE