Full moon happens every now and then. But have you ever considered how this happens and why?
The answer is listed below! So dive in the facts!
- The full moon is the lunar phase when the Moon appears fully illuminated from Earth’s perspective
- This occurs when Earth is located between the Sun and the Moon
- Exactly, when the ecliptic longitudes of the Sun and Moon differ by 180°
- This means that the lunar hemisphere facing Earth is completely sunlit
- It appears as a circular disk
- While the far side is dark
- The full moon occurs once roughly every month
- When the Moon moves into Earth’s shadow, a lunar eclipse occurs
- During which all or part of the Moon’s face may appear reddish due to the Rayleigh scattering of blue wavelengths
- And the refraction of sunlight through Earth’s atmosphere
- Lunar eclipses happen only during full moon
- And around points on its orbit where the satellite may pass through the planet’s shadow
- A lunar eclipse does not occur every month
- Because the Moon’s orbit is inclined 5.14°
- With respect to the ecliptic plane of Earth
- Thus, the Moon usually passes north or south of Earth’s shadow
- Which is mostly restricted to this plane of reference
- Lunar eclipses happen only when the full moon occurs around either node of its orbit
- Therefore, a lunar eclipse occurs approximately every 6 months
- And often 2 weeks before or after a solar eclipse
- Which occurs during new moon around the opposite node
- The interval period between a new or full moon and the next same phase averages about 29.53 days
- It is called a synodic month
- In those lunar calendars in which each month begins on the day of the new moon, the full moon falls on either the 14th or 15th day of the lunar month
- Because a calendar month consists of a whole number of days
- A lunar month may be either 29 or 30 days long
- A full moon is often thought of as an event of a full night’s duration
- This is somewhat misleading because its phase seen from Earth continuously waxes or wanes
- Though much too slowly to notice in real time with the naked eye
- Its maximum illumination occurs at the moment waxing has stopped
- For any given location, about half of these maximum full moons may be visible
- While the other half occurs during the day
- When the full moon is below the horizon
- Many almanacs list full moons not only by date
- But also by their exact time
- Usually in Coordinated Universal Time (UTC)
- Typical monthly calendars that include lunar phases may be offset by one day when used in a different time zone
- Full moon is generally a suboptimal time for astronomical observation of the Moon because shadows vanish
- It is a poor time for other observations because the bright sunlight reflected by the Moon
- Amplified by the opposition surge
- Then outshines many stars
- On 12 December 2008, the full moon occurred closer to the Earth than it had been at any time for the previous 15 years
- This was called a supermoon
- On 19 March 2011, another full supermoon occurred
- Closer to the Earth than at any time for the previous 18 years
- On 14 November 2016, a full supermoon occurred closer to the Earth than at any time for the previous 68 years
- Full moons are traditionally associated with temporal insomnia
- Which is the inability to sleep
- Insanity, hence the terms lunacy and lunatic
- And various “magical phenomena” such as lycanthropy
- Psychologists, however, have found that there is no strong evidence for effects on human behavior around the time of a full moon
- They find that studies are generally not consistent
- With some showing a positive effect
- And others showing a negative effect
- In one instance, the 23 December 2000 issue of the British Medical Journal published two studies on dog bite admission to hospitals in England and Australia
- The study of the Bradford Royal Infirmary found that dog bites were twice as common during a full moon
- Whereas the study conducted by the public hospitals in Australia found that they were less likely
- Historically, month names are names of moons in lunisolar calendars
- Since the introduction of the solar Julian calendar in the Roman Empire
- And later the Gregorian calendar worldwide
- People no longer perceive month names as “moon” names
- The traditional Old English month names were equated with the names of the Julian calendar from an early time
- Soon after Christianization
- According to the testimony of Bede ca. AD 700
- Some full moons have developed new names in modern times
- Lunar eclipses only happen during a full moon and often cast a seemingly reddish tint over the face of the moon
- This has been called a blood moon in popular culture
- The “harvest moon” and “hunter’s moon” are traditional terms for the full moons occurring during late summer and in the autumn
- In the northern hemisphere usually in September and October respectively
- The “harvest moon” is the full moon closest to the autumnal equinox
- Coming anywhere from two weeks before to two weeks after that date
- The “hunter’s moon” is the full moon following it
- The names are recorded from the early 18th century
- The Oxford English Dictionary entry for “harvest moon” cites a 1706 reference
- And for “hunter’s moon” a 1710 edition of The British Apollo
- Where the term is attributed to “the country people”
- The names became traditional in American folklore
- Where they are now often popularly attributed to the Native Americans
- The Feast of the Hunters’ Moon is a yearly festival in West Lafayette, Indiana
- It is held in late September or early October each year since 1968
- In 2010, the Harvest moon occurred on the night of equinox itself for the first time since 1991
- All full moons rise around the time of sunset
- Because the moon moves eastward among the stars faster than the sun its meridian passage is delayed
- Causing it to rise later each day
- On average by about 50.47 minutes
- The harvest moon and hunter’s moon are unique because the time difference between moonrises on successive evenings is much shorter than average
- The moon rises approximately 30 minutes later from one night to the next
- This is because a full moon in September appears to move not straight east but north-east in the sky
- Thus, there is no long period of darkness between sunset and moonrise for several days after the full moon
- Thus lengthening the time in the evening when there is enough light for men to see to work to get the harvest in
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