MOVEMENT OF THE EARTH AND MOON

In this lecture you will learn about:

SEASONS 

 
 

Excellent youtube HERE and HERE that explains the seasons. 

What would happen if the earth did not tilt at 23.5o?
What would happen if the axis always pointed towards the Sun?

The warmest part of Earth gets DIRECT waves of sunlight. The equator always gets direct sunlight, which is why it is always hot there. 

The earths axis is titled 23.5 degrees from the vertical throughout the revolution of the Earth around the Sun.  Because of this the part of Earth above and below the equator alternately get direct Sun for part of the year and indirect light the other part of the year. 

All parts of Earth get the same number of hours and amount of direct light at the equinoxes. 

Here is the Earth as it revolves around the Sun. 

 
SEASONAL MARKERS
Equinoxes and solstices
 

Foucault http://www.calacademy.org/products/pendulum/page5.htm
http://library.thinkquest.org/29033/begin/earthsunmoon.htm

the direction of the axis changes in a slow precession with period of 26,000 years.  To pass thru each of the 12 signs of the zodiac takes about 2100 years.  After 2100 years we move out of one age and into another. Pices was around 60 BC. We are now moving into the age of Aquarius. 
http://ancientegypt.hypermart.net/royalarch/

What does equinox and solstice mean?
Where on Earth gets the most hours of sunlight on a solstice? The least? 
 


 
PHASES OF THE MOON

 
 

"A lunar phase or phase of the moon refers to the appearance of the illuminated portion of the Moon as seen by an observer, usually on Earth. The lunar phases vary cyclically as the Moon orbits the Earth, according to the changing relative positions of the Earth, Moon and Sun. One half of the lunar surface is always illuminated by the Sun (except during lunar eclipses), and hence is bright, but the portion of the illuminated hemisphere that is visible to an observer can vary from 100% (full moon) to 0% (new moon). The boundary between the illuminated and unilluminated hemispheres is called the terminator."

 

TIDES

PRETTY GOOD VISUAL LINK

THESE ARE ALL EXAMPLES OF SPRING AND NEAP TIDES OR "SUN TIDES"

PRETTY GOOD VISUAL

REVIEW QUESTIONS:

draw and/or explain the following
seasons
tides
phases of the moon
eclipses and lack thereof
precession of the equinoxes