What's the difference between a LUNAR ECLIPSE, and a regular NEW MOON?

Question

The eclipse is the result of Earth blocking sunlight that would normally bounce off the moon's surface. But when we see a new moon, or half-moon every couple of weeks... isn't this the same phenomenon? Explain the difference.

Answer 1

A new moon is the shadowed side on the moon when it is between the earth and the sun. When the moon is behind the earth during a full moon, it sometimes goes into the earth's shadow. This is the eclipse. The reason it doesn't happen every month is because the moon wobbles in it's rotation. It usually goes above or below the earth's shadow.

Answer 2

As has been answered a number of times, a new moon is not due to the light being blocked by the earth's shadow. It is due to the fact that the moon earth and sun are positioned such that the sun is shining on the side of the moon which we don't see so the side we do see is dark. Same with a half moon. Nothing to do with the earth's shadow. If the right half of the moon appears light and the left side dark it just means that because of the relative positions of the three bodies the sun is shining directly on the right half of the moon. To visualize the phases of the moon, place a cue ball on a table so it is brightly illuminated by a single window on one side. Half the cue ball should be white and half dark. Now walk slowly around the table in one direction. The cue ball will duplicate the phases of the moon. Notice that when you walk between the window and the ball , the cue ball suddenly gets dark. You have just caused an eclipse of the moon. Notice that just before the "eclipse" you were looking at a bright white ball. All lunar eclipses happen during a full moon. Now, why, then, doesn't an eclipse occur every full moon? Have you noticed how a toy top wobbles in a definite pattern as it slows down? Scientists call this precession. The moon moves the same way. It wobbles slowly as it rotates in its orbit so that during most full moons it is either above or below the shadow of the earth. A lunar eclipse occurs only on the rare occasions that the earth is directly between the earth and the sun during a full moon. Since the moon "wobbles" at a fixed rate and since it also moves in its orbit at a fixed rate scientists can predict with accuracy just when a lunar eclipse will occur.

Answer 3

Your question carries with it the implication that the phases (shapes) of the moon are caused by Earth's shadow. This is not the case. The phases of the moon are caused by the changing perspective by which we view the moon and it's lit and dark sides over the course of it's orbit of the Earth. A lunar eclipse is when the full moon passes into Earth's shadow and is darkened. A new moon is when the moon is between the Earth and the sun and it's dark side is facing us.

You mentioned the half moon, and I made a picture that can help illustrate the cause of the phases of the moon

http://public.clunet.edu/~sjfahmie/halfmoonday.jpg

Answer 4

In a lunar eclipse the Earth comes between the solar and the moon and blots it out for a time. a clean moon is even as the moon is at an attitude the position the lit area of the moon is way flung from the Earth and hence no longer seen. because of the tilt of the Earth, it makes this accessible with no need the moon in the front of the solar to have the "darkish" aspect face us.

Answer 5

A new moon is when the moon is between us and the sun, so the sunlit side of the moon is facing away from us. We see the side of the moon that is not lit (well, we don't see it because its dark).
A lunar eclipse is when the moon is full, but happens to move into the shadow that Earth makes and is no longer sunlit.

Answer 6

a lunar eclipse, the earth passes between the sun and moon, for a new moon, the sun is shining on the moon still, we just have a bad angle to see it. shine a light on a ball, then look at it from the side and back and it should resemble the phases of the moon.

Answer 7

Lunar eclipse is during a full moon not a new moon.

Answer 8

For a lunar eclipse to occur the 3 bodies involved have to be perfectly aligned. If this is not happening you have a new moon instead.

Answer 9

REPEAT THIS:

THE MOON'S PHASES HAVE NOTHING TO DO WITH THE EARTH'S SHADOW.

THE MOON'S PHASES HAVE NOTHING TO DO WITH THE EARTH'S SHADOW.

THE MOON'S PHASES HAVE NOTHING TO DO WITH THE EARTH'S SHADOW.

THE MOON'S PHASES HAVE NOTHING TO DO WITH THE EARTH'S SHADOW.

THE MOON'S PHASES HAVE NOTHING TO DO WITH THE EARTH'S SHADOW.

For love of Mike, why is this so difficult for people to understand?

The phases are just what part of the illuminated side of the moon we see.

Surely it is obvious that the sun can only light up one side of a spherical object? The phases are just how much of that we see as the moon circles the Earth.

(What do you think night and day means - the sun only shines on one half of the Earth at a time. Same for the moon, only the day on the moon is about 28 earth days.