Lunar Eclipse - New Moon -
Solar Eclipse - Full Moon
Some people are wondering about the difference between new moon and a lunar eclipse, as both times, 'you can't see the moon'. There are, however, several fundamental differences :
- New moon happens regularly, about every 30 days. The moon then is located somewhere between the sun and the earth.
Therefore, the sunshine illuminates the rear side of the moon, while the front, which we can see from earth, stays dark. That's why we can't see the new moon.
A particular case of the new moon happens when the moon is not only 'somewhere between' sun and earth, but when the three are really aligned. In that case, the shadow of the moon falls upon the earth, and we get a solar eclipse, partial, annular or total, depending on the perfection of the alignment and the distances between the three celestial bodies.
As the moon is smaller than the earth, it's shadow only wipes a narrow corridor on earth's surface : The solar eclipse can only be seen in a restricted area, and it lasts only a few minutes.
- The opposite of new moon is the full moon. It also happens regularly, but now, the moon is located on the other side; thus, the earth is between the sun and the moon, so that we can see the illuminated face of our natural satellite.
Again, a special case of the full moon happens when the three are nearly perfectly aligned : this time, the shadow of the earth falls upon the illuminated face of the moon, thus darkening it. At this full moon, we have a lunar eclipse.
The lunar eclipse can be seen from half the world (seeing the moon at that time means seeing the eclipse). And as the shadow is bigger than the moon, it can last much longer than a solar eclipse. Additionally, this leads to an increased frequency of lunar eclipses, especially total ones.
- When the shadow of the earth falls upon the moon, this one, on the contrary of new moon, doesn't turn to black. The atmosphere around the earth not only allows us to breath, but also it diffracts the waves of the light, and this differently for each colour. The red part of the light is deflected most. This e.g. leeds to the beautiful red sky during sunrise or sunset.
These red parts of the light are bent into the shadow that the earth casts upon the moon. Therefore, during an eclipse, the moon shows a dimmed, red-brown glow.