Today is Christmas in the Christian world. The full moon also happens to fall on this day. A full moon occurring this time of year is called a cold moon as it is the beginning of winter in the northern hemisphere (though, right now, much of the eastern US is actually warm rather than cold).
The strange thing is that the full moon has not been on Christmas Day since 1977 and will not occur again until 2034.
Nothing else is unusual about the full moon today, but just the date it happens to fall on.
Showing posts with label full moon. Show all posts
Showing posts with label full moon. Show all posts
25 December 2015
02 October 2015
Supermoon Lunar Eclipse
On September 27th, we experienced an event that does not happen very often, a supermoon lunar eclipse. We have had a supermoon before, and I've talked about it (see Supermoon). A supermoon is just the moon at perigee. However, this time, we had a supermoon occur when we had a lunar eclipse.
Lunar eclipses aren't all that rare (they happen once every six months), but to have one occur when the moon is at perigee is a sight to behold. The moon appears the largest and the lunar eclipse at this time is actually the shortest total lunar eclipse to occur. It is the shortest because the moon is at its closest, so it is actually moving at its fastest. Many lunar eclipses can last a few hours, but totality for this eclipse was only an hour and a half.
If you want to know more about lunar eclipses, see here.
Lunar eclipses aren't all that rare (they happen once every six months), but to have one occur when the moon is at perigee is a sight to behold. The moon appears the largest and the lunar eclipse at this time is actually the shortest total lunar eclipse to occur. It is the shortest because the moon is at its closest, so it is actually moving at its fastest. Many lunar eclipses can last a few hours, but totality for this eclipse was only an hour and a half.
If you want to know more about lunar eclipses, see here.
31 July 2015
Blue Moon
Tonight, July 31st, a rare occurrence will happen. You can say that it is something that happens once in a blue moon, because it is a blue moon.
What do we mean by a blue moon? There are actually two definitions of what a blue moon is.
If you miss the blue moon tonight, don't worry. There will be another blue moon on May 21, 2016. This will be the third blue moon in the northern spring (southern fall) of 2016.
What do we mean by a blue moon? There are actually two definitions of what a blue moon is.
- A blue moon is the third full moon in a season where four full moons occur. Most times, there are only three full moons in one season, but on the rare occasion when a full moon is at the beginning of the season, the season may have four.
- A blue moon may also mean the second full moon in a calendar month. The full moon of tonight is this type of blue moon.
If you miss the blue moon tonight, don't worry. There will be another blue moon on May 21, 2016. This will be the third blue moon in the northern spring (southern fall) of 2016.
31 March 2015
Lunar Eclipse of April 4, 2015
Even though we just had a total solar eclipse on March 20th, just two weeks later, there will be a lunar eclipse. In fact, most of the western hemisphere will be able to witness at least part of this eclipse on April 4, 2015.
Remember that eclipse seasons happen every six months and always have a solar eclipse and lunar eclipse two weeks apart. The alignment of the Sun, Earth, and Moon will always determine which one occurs first. However, there are sometimes when the alignments are right, there may be three - a solar eclipse sandwiched between two lunar eclipses. However, this eclipse season there are only the two this year.
From before, we learned that a lunar eclipse will happen during a full moon. The Earth will be between the Moon and the Sun and the shadow of our planet will fall on the Moon, obscuring it. This eclipse will begin at 9:01 UTC. If the Moon is out during this time for you, you will be able to see the eclipse occur.
Remember that eclipse seasons happen every six months and always have a solar eclipse and lunar eclipse two weeks apart. The alignment of the Sun, Earth, and Moon will always determine which one occurs first. However, there are sometimes when the alignments are right, there may be three - a solar eclipse sandwiched between two lunar eclipses. However, this eclipse season there are only the two this year.
From before, we learned that a lunar eclipse will happen during a full moon. The Earth will be between the Moon and the Sun and the shadow of our planet will fall on the Moon, obscuring it. This eclipse will begin at 9:01 UTC. If the Moon is out during this time for you, you will be able to see the eclipse occur.
02 October 2014
October 2014 Lunar Eclipse
Legend
Intense red shading: Observers within this area can see the eclipse from beginning to end.
Red shading right/east of intense shading: Observers within this area can see the eclipse until moonset/sunrise.
Red shading left/west of intense shading: Observers within this area can see the eclipse after moonrise/sunset.
No coloring: Eclipse is not visible at all
Note: Actual eclipse visibility depends on weather conditions
Image and Legend taken from TimeandDate.com
On October 8, 2014, there will be a total lunar eclipse occuring. If you remember from the post about eclipses, lunar eclipes occur during the full moon phase when the Moon's orbit takes it into the shadow of the Earth. As you can see from the image above, Anyone in the intense red region in the middle of the map will get to see the entirety of the lunar eclipse. I live in Pittsburgh, USA, so I will only get to see the beginning just before the sun rises and the moon sets. If you live in China, you will get to see the ending, just after sunset/moonrise.
Another cool thing about this lunar eclipse is due to the sunlight filtering through the atmosphere, the Moon will appear reddish in color.
Another cool thing about this lunar eclipse is due to the sunlight filtering through the atmosphere, the Moon will appear reddish in color.
Here are the times of the lunar eclipse in Universal Time (UTC) -24 hour clock. Add or subtract the appropriate number of hours to get your local time.
- Penumbral eclipse begins (the Moon enters the penumbra of the Earth's shadow) - 8:17
- Partial eclipse begins (Moon enters the umbra of the Earth's shadow) - 9:18
- Full Eclipse begins (Moon entirely in the umbra) - 10:27
- Maximum Eclipse - 10:55
- Full Eclipse ends (Moon begins to leave the umbra) - 11:22
- Partial Eclipse ends (Moon leaves the umbra entirely) - 12:32
- Penumbral Eclipse ends (Moon leaves the penumbra entirely) - 13:32
11 August 2014
Supermoon
I probably should have posted this a couple of days ago, but oh well.
The Supermoon of 2014 just occured this past weekend (August 10).
The Supermoon is not the newest superhero of DC or Marvel.
The Supermoon is the full moon happened to occur during perigee. The Moon appeared the largest because it happened to be at its closest in its orbit to Earth. Tides (which will be discussed further in a future post) happened to be a tad higher, but nothing else really is affected by a Supermoon. It's just cool to see the Moon so large.
The Supermoon of 2014 just occured this past weekend (August 10).
The Supermoon is not the newest superhero of DC or Marvel.
The Supermoon is the full moon happened to occur during perigee. The Moon appeared the largest because it happened to be at its closest in its orbit to Earth. Tides (which will be discussed further in a future post) happened to be a tad higher, but nothing else really is affected by a Supermoon. It's just cool to see the Moon so large.
26 July 2014
Eclipses
Previously, we learned about the phases of the Moon. We saw how it goes from new Moon to full Moon back to new Moon again. We know that during the new phase, the Moon is between us and the Sun. During the full phase, the Earth is between the Sun and the Moon. We also know the apparent diameter of the Sun and the Moon are nearly identical, at about 0.5°. So how come we don't see the Moon blocked out when its full and why isn't the Sun always eclipsed during the new Moon phase?
The main reason why is the Earth and the Moon do not orbit in the same plane. The Moon's inclination is about 5° compared to the ecliptic. Therefore, during most new Moon phases or most full Moon phases, the Moon is not in the same alignment with the Earth and the Sun. This 5° inclination leads to the eclipses to happen every six months.
Lunar eclipses occur during the full Moon phase as the Earth is between the Moon and the Sun. If the Moon is completely in the shadow, or umbra, of the Earth. Since the Earth is so much larger than the Moon, the shadow of the Earth completely envelopes the Moon during a lunar eclipse. Also, this allows a lunar eclipse to occur even if the Earth, Sun and Moon are not completely in line. If the Moon is slightly out of the umbra and partially in the penumbra, partial lunar eclipses will occur. From viewing partial lunar eclipses, ancient astronomers could tell that the Earth was round, not flat, because of the shape of the Earth's shadow on the Moon.
Solar eclipses occur during the new Moon phase when the Moon crosses in front of the Sun. These are only total if the Moon is near perigee and the Sun, Moon, and Earth are completely aligned. If the Moon is nearer apogee than perigee, a solar eclipse will be annular, or ring-like, because there will be a ring of sunlight around the outline of the Moon. As with lunar eclipses, if the Moon is slightly off center of the ecliptic, then a partial solar eclipse will occur.
In the future, total solar eclipses will not longer occur because the Moon is moving away from the Earth at a rate of 2 cm/century. We will learn more about the recession of the Moon later.
The main reason why is the Earth and the Moon do not orbit in the same plane. The Moon's inclination is about 5° compared to the ecliptic. Therefore, during most new Moon phases or most full Moon phases, the Moon is not in the same alignment with the Earth and the Sun. This 5° inclination leads to the eclipses to happen every six months.
There are two types of eclipses: solar eclipses and lunar eclipses. Solar eclipses occur when the Moon crosses in front of the Sun, blocking us from seeing the Sun on Earth. Lunar eclipses occur when the Moon passes through the shadow of the Earth. A lunar eclipse (or a solar eclipse) follows two weeks after the associated solar (or lunar) eclipse. Solar eclipses and lunar eclipses never occur more than 14 days apart.Lunar eclipses occur during the full Moon phase as the Earth is between the Moon and the Sun. If the Moon is completely in the shadow, or umbra, of the Earth. Since the Earth is so much larger than the Moon, the shadow of the Earth completely envelopes the Moon during a lunar eclipse. Also, this allows a lunar eclipse to occur even if the Earth, Sun and Moon are not completely in line. If the Moon is slightly out of the umbra and partially in the penumbra, partial lunar eclipses will occur. From viewing partial lunar eclipses, ancient astronomers could tell that the Earth was round, not flat, because of the shape of the Earth's shadow on the Moon.
Solar eclipses occur during the new Moon phase when the Moon crosses in front of the Sun. These are only total if the Moon is near perigee and the Sun, Moon, and Earth are completely aligned. If the Moon is nearer apogee than perigee, a solar eclipse will be annular, or ring-like, because there will be a ring of sunlight around the outline of the Moon. As with lunar eclipses, if the Moon is slightly off center of the ecliptic, then a partial solar eclipse will occur.
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| Total Solar Eclipse (NASA) |
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| Annular Solar Eclipse (Wikipedia) |
10 July 2014
The Phases of the Moon
We are going to take a break from talking about Venus to explain about the phases of the Moon. This background is necessary when we get into the next post about Venus.
The Moon goes through basically eight phases as it orbits the Earth. These phases are a result of the Moon's alignment with both the Earth and the Sun. Before we go into the descriptions of the phases, we should define two terms:
The sidereal lunar cycle, or "sidereal month" is how long it takes the Earth, Moon, and a background star to line up. This period last about 27.3 days. After another 2.2 days, the Earth, Moon, and Sun are lined up in what is called the lunar month, or synodic month. This period is approximately 29.5 days. The difference between these periods is because as the Moon orbits the Earth, the Earth is also orbiting the Sun.
The first phase during the lunar month is called the "New Moon". Basically, it is when the Moon is between the Earth and the Sun. The unilluminated face of the Moon is pointed towards the Earth. However, the new Moon is not completely dark. Earthshine, reflection of sunlight off the Earth's surface can illuminate the surface of the Moon.
The Moon goes through basically eight phases as it orbits the Earth. These phases are a result of the Moon's alignment with both the Earth and the Sun. Before we go into the descriptions of the phases, we should define two terms:
The sidereal lunar cycle, or "sidereal month" is how long it takes the Earth, Moon, and a background star to line up. This period last about 27.3 days. After another 2.2 days, the Earth, Moon, and Sun are lined up in what is called the lunar month, or synodic month. This period is approximately 29.5 days. The difference between these periods is because as the Moon orbits the Earth, the Earth is also orbiting the Sun.
The first phase during the lunar month is called the "New Moon". Basically, it is when the Moon is between the Earth and the Sun. The unilluminated face of the Moon is pointed towards the Earth. However, the new Moon is not completely dark. Earthshine, reflection of sunlight off the Earth's surface can illuminate the surface of the Moon.
The next phase is the Waxing Crescent phase. Waxing in astronomy means that something is increasing in size. As the Moon moves around the Sun, a sliver of the Moon on the right limb is illuminated by the Sun as seen from the Earth. What we see is the crescent shape of the Moon.
The Moon is said to be aging as it goes from New Moon to Waxing Crescent. About a week after the New Moon, the Moon reaches the First Quarter phase because it has reached the end of one quarter of the lunar cycle. The entire right half of the Moon is illuminated as seen from the Earth.
The next phase is called Waxing Gibbous. The illuminated surface of the moon crosses the center of the moon and spills over into the left half of the Moon. The illuminated portion of the Moon resembles an oval with pointed ends.
Halfway through the lunar cycle, we hit the Full Moon. No, werewolves do not appear during the Full Moon. People do not get crazy during the Full Moon, though it may appear to be so. The Full Moon is the phase where the Earth is between the Sun and the Moon and from Earth we see the entire face of the Moon illuminated.
After the full Moon passes, the illuminated portion of the Moon begins to decrease, or wane. The next phase is the Waning Gibbous phase. The right limb has a darkened crescent shape, and the left half and a portion of the right half of the Moon are illuminated, opposite the Waxing Crescent phase.
After three weeks in the lunar cycle, the Moon reaches the Last Quarter or sometimes called Third Quarter. It is called this because either the Moon is at the beginning of the last week of the lunar cycle or the end of the third week of the lunar cycle.
In the final week before the Moon is "reborn" into the New Moon, the Moon goes through the Waning Crescent phase. Only a sliver on the left limb of the Moon is illuminated.
Here is an image showing the relative position of the phases with respect to the Earth and the Sun.
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