| January » | New Moon Jan 6, 2019 01:28 UTC |
Full Moon Jan 21, 2019 05:16 UTC Lunar Eclipse Times> |
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| February » | New Moon Feb 4, 2019 21:03 UTC |
Full Moon Feb 19, 2019 15:53 UTC |
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| March » | New Moon Mar 6, 2019 16:04 UTC |
Full Moon Mar 21, 2019 01:42 UTC |
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| April » | New Moon Apr 5, 2019 08:50 UTC |
Full Moon Apr 19, 2019 11:12 UTC |
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| May » | New Moon May 4, 2019 22:45 UTC |
Full Moon May 18, 2019 21:11 UTC |
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| June » | New Moon Jun 3, 2019 10:01 UTC |
Full Moon Jun 17, 2019 08:30 UTC |
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| July » | New Moon Jul 2, 2019 19:16 UTC |
Full Moon Jul 16, 2019 21:38 UTC |
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| August » | New Moon Aug 1, 2019 03:12 UTC |
Full Moon Aug 15, 2019 12:29 UTC |
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| September » | Full Moon Sep 14, 2019 04:33 UTC |
New Moon Sep 28, 2019 18:26 UTC |
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| October » | Full Moon Oct 13, 2019 21:08 UTC |
New Moon Oct 28, 2019 03:38 UTC |
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| November » | Full Moon Nov 12, 2019 13:34 UTC |
New Moon Nov 26, 2019 15:05 UTC |
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| December » | Full Moon Dec 12, 2019 05:12 UTC |
New Moon Dec 26, 2019 05:13 UTC |
WHAT MAKES THE MOON FULL?
Since the time of our earliest ancestors, mankind has used the motions of the heavenly bodies to mark time and keep the seasons. The annual movement of the Sun being perhaps the most important as relating to seasons for harvest, planting, and the long dark nights of Winter. The Moon however has played no less a role to our time keeping efforts, and the word “month” is even derived from the word for Moon, with a month being the time period between one New Moon and the next.
What is a New Moon? From the standpoint of an observer on Earth, the moon goes through a very predictable periodic cycle. Each day, the moon appears to change shape! For a short time the moon is dark and cannot be seen, we call this “New Moon” and it is both the birth and death of the lunar cycle. Starting as a tiny sliver of light at first, it grows (waxes) daily as more and more of the moon becomes brighter until finally, the moon is fully lit and appears as a great round orb shining down. This is called Full Moon, and many cultures around the world have names for the Full Moons that occur throughout the year, such as Harvest Moon, or the Cold Moon. After the Moon is full, it begins to wane each day as the bright round moon is reduced again to a tiny sliver of light and finally to disappear to begin the cycle all over again.
What physically causes what we observe in the sky with our own eyes? Consider the pattern of the lunar phases in relation to the Sun. As the moon moves further from the Sun in our sky, it grows more and more full. As the moon moves closer to our Sun, it wanes and darkens. We’ve known since at least the ancient Greeks what was going on here. The moon is round, like a giant ball and it revolves around the earth. Sunlight from the Sun is what is lighting up the Moon. Vampires beware, moonlight is nothing more than reflected sunlight! New Moon when the moon is dark occurs when the Moon is between the Earth and the Sun, and we see the dark side of the moon (that’s right, the dark side is not the far side, it’s just the side opposite from the Sun). As the Moon slides away from the Sun in our sky, we see the thin crescent, the edges of the great ball that is the moon being illuminated by sunlight hitting it from the edges. The moon waxes through the gibbous phases until the moon is on the other side of the earth, directly opposite from the Sun. As it moves in its orbit there is a moment in time when the Moon is directly opposite the Sun and is fully illuminated from our point of view on earth. This moment is Full Moon.
Now, the Moon continues around and approaches the Sun from the other side, and begins to wane in brightness as less and less of the Moon from our vantage point receives light from the Sun. The gibbous and crescent phases decline from the opposite side of the Moon from where they were growing as we approached New Moon because now, like on a merry-go-round, the Moon approaches the Sun from the opposite side from which it left. The Moon’s orbit, or path around the Earth is not fixed, but wobbles as well. Sometimes the Full Moon will pass directly into the shadow of the Earth and we observe this as a Lunar Eclipse. Everyone on Earth who can see the Moon can see a Lunar Eclipse when it occurs because the Moon is physically in the shadow of the Earth and not receiving any light. A Solar Eclipse on the other hand can only occur during New Moon and this happens on occasion when the Moon passes directly in front of the Sun on its orbit. The Moon is small, and so the shadow from the Moon cannot cover the entire Earth and instead creates a shadow that races across the globe at supersonic speeds as the Moon passes by.
Astronomers can calculate the exact times of the New and Full Moon to great accuracy, and you can find these times in most almanacs. The orbit of the Moon as well as our path around the Sun are quite well understood. It takes the moon about 27.32 days to completely orbit the Earth, yet the Lunar Cycle is about 29.53 days long. Why the difference? Because both the Earth and Moon are also traveling around the Sun and the extra time for the lunar cycle is “catch up” time for the Moon to get into the same relative position to the Sun as we move around in our great circle.
Both New and Full Moon are very specific instances of time when the Moon is at a specific location in its orbit around the Earth. This moment in time doesn’t care what time zone anyone on Earth is located in either! Astronomers use a standard called Universal Coordinated Time, which is the time at Greenwich England. Everyone else on earth is in a time zone that is some offset from this coordinated time. On the East Coast of the United States for example, the time zone is 5 hours earlier (or 4 hours during Daylight Savings Time) than it is in Greenwich while people living in California are another 3 hours displaced for their local time. This makes civil life make more sense as sunset is “about” 5 O’clock for everyone because the time zones flow all the way around the Earth, and this keeps the Sun ins “about” the same place for everyone during their same times of day. Have you ever seen a television show advertised to come on at 8pm Eastern, but 7pm Central? Time zones at work, the broadcast is at the same time for everyone, but their local time zones, or offsets from Greenwich are different. This is why New Moon might be at 1am for someone on the East coast, but at 10pm the previous day for someone on the West coast. It’s the same moment in time, but because of civil time zones (and our round Earth), our local clocks are different.




