Transcript Earth and Moon Notes

Earth and Moon Notes
Chapter 24
GRAVITY
• Causes spherical shape of planets
• Decreases as items move farther apart
• Increases with size of objects
Rotation
• Movement on an axis
• Causes day and night
• Takes 24 hours (one day) to complete one
rotation (or 23 hours 56 minutes)
Revolution
•
Movement around another body
Earth around the sun
•
Causes seasons
•
365 ¼ rotations (days) for one revolution
•
Satellite – one body orbits another
–
(The earth is a satellite of the sun)
EARTH
• The orbit is elliptical (oval) in shape
• The tilt is 23.5º and always points toward the
north star
Solstice
• Time when the sun is the furthest distance
from the earth.
• Summer solstice – Longest day, June 21st or
22nd, Northern hemisphere’s toward the sun
• Winter solstice – Shortest day, December
21st or 22nd, Southern hemisphere toward the
sun
Equinox
• The sun is directly over the earth’s equator.
• The tilt is not toward or away from the sun.
• Spring equinox – March 21 or 22nd
• Fall equinox – September 21st or 22nd
Moon
• Maria – dark colored regions on the moon
• Craters – large depressions formed by
meteors (meteorite when it falls to the earth)
• Moon rocks – give us clues on how the moon
was formed
Moon continue:
• One rotation takes 27.3 days
• One revolution takes 27.3 days
• This means we will always see the same
side of the moon
Moon Phases
It takes
29.5 days
to complete all
eight phases.
Moon Phases
http://www.astro.wisc.edu/~dolan/java/MoonPhase.html
New Moon
Full
Crescent
waxing
Gibbous
waning
1st Quarter
Last (third)
Quarter
Gibbous
waxing
Crescent
waning
Eclipse
• Solar Eclipse – earth
moves into the moons
shadow
• Lunar Eclipse – sun,
moon & Earth are
lined up with each
other.
Tides
• Neap Tide
– Earth, moon, and sun
form a right angle
– During the quarter
moons
– Weaker tides overall
due to suns counter
gravity
• Spring Tide
– Earth, moon and sun
are lined up
– During Full and New
moon
– Stronger tides due to
gravity from moon and
sun
CREDITS
• http://www.astro.wisc.edu/~dolan/java/Moo
nPhase.html