Post by Magill on Jun 25, 2004 12:51:39 GMT -5
BladeStar--I think you're contradicting yourself. First you define a full moon this way:
2. A "Full Moon" is one in which the Moon is receiving enough light from the sun (unblocked by the Earth) to have about 50% of it's surface alight. You CAN have a full moon during the day under the right circumstances, just as you can see the moon on any day if you look hard enough and it is in the right place in your hemisphere, night time is not a requirement.
and then you quote this:
A full moon has nothing to do with it's percent illumination, it has to do with it's appearance from earth. Except during a lunar eclipse, 50% of the moon's surface is always illuminated. A full moon is when the moon appears to be an entire disc, rather than a sliver or a fraction of a disc. In other words, the side of the moon that faces Earth is fully illuminated. By definition, the moon has to be on the opposite side of the Earth as the sun. Thus the moon can't be visible during the day.
You can only get lunar eclipses during the full moon, just as you can only get solar eclipses during the new moon (because the moon is in between the Earth and the sun).
I don't want you to feel like I'm picking on you--I took astronomy in high school and our instructor always tried to make sure we got any astronomical misconceptions clarified, and I guess some rubbed off. Maybe Lissa has the best idea.
BladeStarr said:
2. A "Full Moon" is one in which the Moon is receiving enough light from the sun (unblocked by the Earth) to have about 50% of it's surface alight. You CAN have a full moon during the day under the right circumstances, just as you can see the moon on any day if you look hard enough and it is in the right place in your hemisphere, night time is not a requirement.
and then you quote this:
The Full Moon is opposite the Sun, meaning that it rises at roughly sunset and sets at roughly sunrise. It is in the sky all night long. It occurs two weeks after New Moon, a week after First Quarter Moon, and a week before Last Quarter Moon. If you use the same reasoning as we do with "quarter" Moons, you would call this the "Half Moon," since we see only half the surface of the Moon (the other half being on the far side). But since the full side facing us is illuminated, it is the "full" Moon. Lunar eclipses can sometimes occur at the phase, usually two to three times a year.
A full moon has nothing to do with it's percent illumination, it has to do with it's appearance from earth. Except during a lunar eclipse, 50% of the moon's surface is always illuminated. A full moon is when the moon appears to be an entire disc, rather than a sliver or a fraction of a disc. In other words, the side of the moon that faces Earth is fully illuminated. By definition, the moon has to be on the opposite side of the Earth as the sun. Thus the moon can't be visible during the day.
You can only get lunar eclipses during the full moon, just as you can only get solar eclipses during the new moon (because the moon is in between the Earth and the sun).
I don't want you to feel like I'm picking on you--I took astronomy in high school and our instructor always tried to make sure we got any astronomical misconceptions clarified, and I guess some rubbed off. Maybe Lissa has the best idea.