THE EARTH IN MOTION

General Information The sun produces light. The moon reflects light. The earth is in orbit around the sun. The moon is in orbit around the earth. The moon’s path (orbit) is constant, but what we see from earth depends on the alignment of the earth, moon, and sun. The moon’s shape never changes, but how we view the moon changes. Moon phases occur in a set order and in a predictable schedule because of the alignment of the earth, moon, and sun.

General information The Earth is an oblate spheroid. This the earth is a tad wider than it is tall, giving it a slight bulge at the equator. This shape is known as an ellipsoid or more properly, geoid (earth-like). The diameter at the equator is 40,075.16 km and 40,008 km from pole to pole. The distance from the Earth to the Sun is 150,000,000 km

Movement of the planets The planets move in an elliptical orbit around the sun. This orbit is not a perfect circle but oval. The direction of the planet is continually changing as they follow this oval pathway. The planet is constantly accelerating. Movement of planet Planet Pedal To The Metal !!!

The gravitational attraction between the sun and a planet is less when the planet is farther from the sun

It takes the Earth 23 hours and 56 minutes to rotate once on its axis The Earth-Sun System It takes one year or 365.25 days for the Earth to revolve once around the Sun It takes the Earth 23 hours and 56 minutes to rotate once on its axis The Earth’s rotation causes day and night The side of the Earth facing the Sun gets light (daytime), the side that faces away from the Sun is without light (nighttime).

The Moon

WHAT IS THE EARTH’S POSITION IN SPACE RELATIVE TO THE SUN AND MOON? The relative position of the sun, the moon, and the earth determine what part of the lighted surface of the moon is facing the earth. Observers on the earth are only able to see the surface lighted by the sun. The moon thus goes through phases when we view it from the Earth.

If the moon is directly between the sun and the earth, it is not visible at all. The moon phase is called the new moon in this position. When the moon is nearly between the earth and the sun only a small portion on the lighted surface can be seen from the earth. The moon phase is called a crescent when it is in this position. If the sun moon and earth form a right angle the first or third quarter phase is visible from the earth. http://www.astronomynotes.com/nakedeye/s13.htm

When the moon, earth, and sun angle are greater than 90 degrees more than one half of the moon will be visible when viewed from the earth. This view is classified the gibbous phase. If the moon, earth and sun line up to form a 180 degree angle all of the lighted part of the moon is visible from the earth. This view is the full moon phase.

These 4 moon images show how the moon appears from Earth from the positions shown in the previous slide.  

Tides and the Moon

The Moon and the Tides The tides are caused by the gravitational pull of the moon and the sun on the earth. Because water is a liquid and free to flow it is constantly being pulled toward the largest objects that are in our solar system and that are close enough to still have a gravitational pull. The diagram shows that whenever the sun, earth, and moon line up the highest tides of the month happen. These tides are called spring tides.

The highest tides of the month are called spring tides The highest tides of the month are called spring tides. Spring tides form when the moon sun and earth form a straight line. The gravitational affects of the sun and the moon work together to create higher tides. Sun Moon

Neap tides have the smallest difference between high and the low tides Neap tides have the smallest difference between high and the low tides. Neap tides happen when the sun, earth, and moon form a right angle. The gravitational forces of the moon and the sun work against each other at this time resulting in the weakest tides of the month. Sun Moon

What Does the Pull of the Moon Do to the Oceans What Does the Pull of the Moon Do to the Oceans? The gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon. Another bulge occurs on the opposite side of the earth because the water flattens out in both directions on a linear plane. (Squish a ball of Play Doe and you will see it bulge in two directions). Since the earth is rotating while this is happening, two tides occur each day.

The alignment of the earth, moon, and sun during solar and lunar eclipses

What is the cause of a solar eclipse? A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partially obscuring Earth's view of the Sun. This configuration can only occur during a new moon, when the Sun and Moon are in conjunction as seen from the Earth. Total solar eclipses (no light is evident) are very rare at any given place on earth but regular solar eclipses take place annually This year eclipse will take place on Aug 1, 2008 Photo of 1999 total eclipse as seen In France Conjunction is a term used in positional astronomy and astrology. It means that, as seen from some place (usually the Earth), two celestial bodies appear near one another in the sky. The event is also sometimes known as an appulse. Annular Eclipse

Lunar Eclipse During a lunar eclipse, the moon passes through the shadow of the Earth. As we look at the moon from the Earth, it looks to us as if the shadow of the Earth is slowly covering the moon. A lunar eclipse only takes place when the Earth is in between the sun and the moon (full moon) Depending on the elliptical of the moon and earth lunar eclipses take place twice a year (This year Feb 21st, and Aug 16th 2008)