Moon Phases #rockinreview


Moon phases:

Waxing - In the Northern Hemisphere, if the left side of the moon is dark and the light part is growing (moving toward a full moon).

Waning - If the right side of the moon is dark and the light part is shrinking, the moon is past full and moving toward a new moon.

Gibbous - When the Moon is more than half full, but not quite fully illuminated, when you look at it from the perspective of Earth. The reason the light changes has to do with how the Moon orbits the Earth.

Gibbous Moon

Gibbous - It’s when the Moon is more than half full, but not quite fully illuminated, when you look at it from the perspective of Earth. The reason the light changes has to do with how the Moon orbits the Earth.

Crescent Moon

Crescent - A crescent moon is part way between a half moon and a new moon, or between a new moon and a half moon.

Pattern of a Waxing Moon:

1.  A waxing crescent moon - Seen as a slim crescent in the west after sunset a day to several days after the new moon (also called a young moon).  At this moon phase, the Earth, moon and sun are located nearly on a line in space.

2. First quarter moon - A first quarter moon rises at noon and is high overhead at sunset. It sets around midnight.  A first quarter moon shows half of its lighted hemisphere – half of its day side – to Earth.  This moon is called a quarter moon and not a half moon because it is one quarter of the way around in its orbit of Earth, as measured from one new moon to the next.  First quarter moon comes a week after new moon.  The moon in its orbit around Earth is at right angles to a line between the Earth and sun.

3.  Waxing gibbous moon - It’s more than half-lighted, but less than full.  This moon phase comes between one and two weeks after new moon.  The moon has moved in its orbit so that it’s now relatively far from the sun in our sky. A waxing gibbous moon rises during the hours between noon and sunset. It sets in the wee hours after midnight.

Full Moon:

At full moon, the moon and sun are on a line, with Earth in between. It’s as though Earth is the fulcrum of a seesaw, and the moon and sun are sitting on either end of the seesaw. So as the sun sets in the west, the full moon rises. When the sun is below our feet at midnight, the full moon is highest in the sky. When the sun rises again at dawn, the full moon is setting.  Full moon always comes about two weeks after new moon, when the moon is midway around in its orbit of Earth, as measured from one new moon to the next.

Pattern of a Waning Moon:

1.  Waning gibbous moon - A waning gibbous moon rises over the eastern horizon in the hours between sunset and midnight.  The moon is past full now. Once again, it appears less than full but more than half lighted.

2.  Last quarter moon - It rises around midnight, appears at its highest in the sky at dawn, and sets around noon.  Last quarter moon comes about three weeks after new moon. Now, as seen from above, the moon in its orbit around Earth is at right angles to a line between the Earth and sun. The moon is now three-quarters of the way around in its orbit of Earth, as measured from one new moon to the next.

3.  Waning crescent moon - Sometimes called an old moon. It’s seen in the east before dawn.  Now the moon has moved nearly entirely around in its orbit of Earth, as measured from one new moon to the next.   Because the moon is nearly on a line with the Earth and sun again, the day hemisphere of the moon is facing mostly away from the earth once more. Only a slender fraction of the moon’s day side, a crescent moon can be seen.

4.  New moon - Once each month, the moon comes all the way around in its orbit so that it is more or less between the earth and the sun.  On the day of new moon, the moon rises when the sun rises. It sets when the sun sets. It crosses the sky with the sun during the day.  The new moon s to close to the sun to be seen from the earth and it's lighted hemisphere is facing away from the earth which is another reason the new moon can't be seen.

Affects of the moon on the ocean tides.

The Lunar Cycle:

Refers to the moon's continuous orbit around the earth. As the moon orbits the earth, its appearance (the "phase") changes and thus gives us an indication of the moon's progress in the cycle (the "age").  This complete lunar cycle (New Moon to New Moon) is also called a "lunation". During this time the moon will completely circle the earth.  The lunar cycle takes 29.53 days.

Nicolai Coppernicus

Nicolai Copernicus was a famous astronomer who said that the sun, not the earth was the center of the universe which lead to our current understanding of the relationship between the sun and the earth.  He believed that the size of each planet's orbit depends on it's distance from the sun.


Why do we have seasons - The earth orbits around the sun on a tilted axis which causes the change in seasons.  When the earth's axis points towards the sun, it is summer for that hemisphere. When the earth's axis points away, winter can be expected. Since the tilt of the axis is 23 1/2 degrees, the North Pole never points directly at the Sun, but on the summer solstice it points as close as it can, and on the winter solstice as far as it can. Midway between these two times, in spring and autumn, the spin axis of the earth points 90 degrees away from the sun.  When the sun is overhead, the light is falling straight down and so more light (and more heat) hit the ground. When the sun is lower in the sky, the light gets more spread out over the surface of the earth, and less heat can be absorbed. Since the earth's axis is tilted, the sun is higher when you are on the part of the earth where the axis points more towards the sun, and lower on the part of the Earth where the axis points away from the sun.  This causes the different temperatures and the different seasons.


The sun is closer to the earth in the winter, why is it not warmer?

During the winter, the sun's rays hit the Earth at a shallow angle. These rays are more spread out, which minimizes the amount of energy that hits any given spot. Also, the long nights and short days prevent the Earth from warming up.

Lunar Eclipse

Why is there not a lunar eclipse every month?

The Moon's orbit is inclined 5.2 degrees to the Plane of the Ecliptic, which is the plane of the Earth's orbit around the Sun. As a result of this incline, the Moon wanders over a large area of the sky, sometimes passing through the plane of the Earth's orbit, other times passing high above. This creates many interesting phenomena of the Moon, from changes in its appearance to variations in the the tides. It also affects the timing and circumstances of lunar and solar eclipses.  Most of the time, the New Moon passes high above the Sun or far below, and does not cross over the face of the Sun.

Causes of a lunar eclipse
Day and Night

Why do we have day and night?

the Earth has an axis but it is not straight up. This is because the Earth is not spinning upright. The Earth is slightly tilted or leaning on its side by 23.5O degrees while spinning toward the East.  Sunlight falls only on one side of the Earth. This side of the planet will be experiencing daylight. Because the Earth is rotating, the opposite side of the Earth away from the Sun will be experiencing night. After some time, the part of the Earth experiencing daylight will experience night. Rotation of the Earth causes night and day to alternate.

Model of why we have day and night
Equinox and Solstice

Equinox - the time when the sun crosses the plane of the earth's equator,making night and day of approximately equal length all over the earth, occurring about March 21 (vernal equinox or spring equinox)and September 22 (autumnal equinox)

Solstice - Either of the two times in the year, the summer solstice and the winter solstice, when the sun reaches its highest or lowest point in the sky at noon, marked by the longest and shortest days.


During his lifetime he was primarily known for his achievements in meteorology and as a pioneer of polar research, but today he is most remembered for advancing the theory of  Continental drift. Wegener was involved in several expeditions to Greenland to study polar air circulation before the existence of the jet stream was accepted. Expedition participants made many meteorological observations and achieved the first-ever overwintering on the inland Greenland ice sheet as well as the first-ever boring of ice cores on a moving Arctic glacier.

Convergent:coming closer together, especially in characteristics or ideas.

Divergent:tending to be different or develop in different directions.

Transformation boundaries: A transformation boundary (or conservative boundary) is where two of the floats - two tectonic plates - side alongside each other.

The Cascadia subduction zone is the plate that's just off the coast of washington

Tetonic plates and the formation of the Cascades

For about 200 million years the Pacific Northwest region has been at an active plate boundary, specifically an ocean continent convergent plate boundary with a subduction zone. Subduction has created most of the volcanoes and mountain ranges of the Northwest.  Late in the Triassic period the Pangaean supercontinent began to rift and break into separate continents drifting apart from each other. The North American continent began separating from the other parts of the supercontinent and drifting to the west, into what is now the Pacific Ocean basin. An ocean-continent convergent plate boundary formed along what is now the North American west coast, as the North American continent began moving across the ocean basin. Subduction began in the Pacific Northwest, accompanied by the geological processes typical of a subduction zone-eruption of composite cones in a volcanic arc, accretion of terranes and formation of mountain ranges.

Convection Currents and their role in plate tectonics

Convection currents:  The rising and sinking movement of a liquid or gas, but not a solid substance due to changes in density is known as a "convection current."

Large convection currents in the aesthenosphere transfer heat to the surface, where plumes of less dense magma break apart the plates at the spreading centers, creating divergent plate boundaries.

As the plates move away from the spreading centers, they cool, and the higher density basalt rocks that make up ocean crust get consumed at the ocean trenches/subduction zones. The crust is recycled back into the aesthenosphere.

Rift Zone:  a feature of some volcanoes, especially shield volcanoes, in which a linear series of fissures in the volcanic edifice allows lava to be erupted from the volcano's flank instead of from its summit.

Subduction zone:  a boundary where two tectonic plates collide and, because of differences in density, one dives beneath the other. This occurs frequently where an oceanic plate meets a continental plate. The denser and thicker oceanic plate is shoved underneath the less dense continental plate.

Channeled Scablands:

The Channeled Scablands were formed by a series of floods of tremendous mangitude, resulting from the failure of a 1/4-mile-high ice dam that held back a lake in western Montana during the Ice Ages (18,000 to 13,000 years before the present). The "Missoula Floods" sent torrents coursing across Washington with discharge rates as high as 20 million cubic feet per second. The water reached depths as high as 250 meters, and speeds as high as 30 meters per second (68 mph). The resulting terrain is characterized by coulees (dry valleys), giant gravel bars, giant current ripples, hanging valleys, "scabland terrain" riddled with potholes, and other features.