28 terms

The sun earth moon system

earth's shape
spherical, but not perfect
imaginary line around which earth spins
spinning of Earth on its imaginary axis, which takes about 23 hours and 56 minutes to complete and causes day and night to occur
Earth's poles
north and south pole
Earth's yearlong elliptical orbit around the sun
elongated, closed curve that describes Earth's yearlong orbit around the Sun
earth's axis tilt
23.5°, causes seasons
either of two times of the year when the sun crosses the plane of the earth's equator and day and night are of equal length, dates are March 20, 21 in the spring and September 22, 23 in the fall
either of the two times of the year when the sun is at its greatest distance from the celestial equator, dates are june 21, 22 in the summer which is the longest and december 21, 22 in the winter which is the shortest
appearance of moon
changes in this caused by revolution
moon's rotation
27.3 days to complete full rotation
moon's revolution around earth
27.3 days to complete full circle
new moon
moon phase that occurs when the Moon is between Earth and the Sun, at which point the Moon cannot be seen because its lighted half is facing the Sun and its dark side faces Earth
waxing crescent
A phase of the moon coming after a new moon and before a 1st quarter moon that is a lit up crescent on the right
first quarter
the right half of the moon appears lit
waxing gibbous
a phase of the moon that comes after a 1st quarter moon and before a full moon where almost all of the moon is lit up from the right to the left, except a small bit on the left.
full moon
phase that occurs when all of the Moon's surface facing Earth reflects light.
waning gibbous
a phase of the moon that comes after a full moon and before a last quarter moon where all of the moon is lit up except for a small bit on the right side of the moon that we can see.
last quarter
We can see exactly 1/2 of the Moon's lighted surface, during the latter half of the night. (see left half)
waning crescent
phase of the moon that comes after a last quarter moon and before a new moon where only the left sliver of the moon is visible and has a crescent shape
one celestial body obscures another
cause of eclipse
the revolution of the moon
solar eclipse
occurs when the Moon passes directly between the Sun and Earth and casts a shadow over part of Earth
a region of complete shadow resulting from total obstruction of light
a fringe region of partial shadow around an umbra
lunar eclipse
the blocking of sunlight to the moon that occurs when Earth is directly between the sun and the moon
dark-colored, relatively flat regions of the Moon formed when ancient lava reached the surface and filled craters on the moon's surface
impact theory
Theory states that the moon was formed around 4.6 billion years ago when a Mars sized object collided with earth, throwing gas and debris into orbit. after this, the debris condensed and formed the moon