Monday, May 7, 2012

Supermoon and moon phases: Part 2



Supermoon Returns in May 2012 | Video

From YouTube channel VideoFromSpace

The full Moon will be up to 14% larger and 30% brighter than others during the year. The reason for this phenomenon is that the Moon becomes full on its closest approach to Earth on May 5, 2012, also known as the perigee full Moon.

**************************************************

I was outside for an extended period last evening, the night after supermoon, and it was probably the same view. Perhaps it was only 12% bigger than usual. It occurred to me that since this happening is 13 1/2 months apart; psychologically, people don't make note of it in nearly the same way as they might with Yule. I think that I will make a note on the right column here, with next year's Supermoon date, which happens to be June 23, 2013. I mean, it would be nice to have a good month to plan for it; which again, is something that someone would not due to the staggered date of occurrence. Also, perhaps the same for the next lunar eclipse, and other solar happenings.

"The supermoon of 2012 is over, but the joys of moongazing are not. Even though Saturday night's lunar showing was the biggest and brightest of the year, the views are nearly as good anytime around the full moon — tonight, for example." --Alan Boyle, 'Your views of the supermoon'



The original meaning of the phrase new moon was the first visible crescent of the Moon, after conjunction with the Sun. This takes place over the western horizon in a brief period between sunset and moonset, and therefore the precise time and even the date of the appearance of the new moon by this definition will be influenced by the geographical location of the observer. The astronomical new moon, sometimes known as the dark moon to avoid confusion, occurs by definition at the moment of conjunction in ecliptic longitude with the Sun, when the Moon is invisible from the Earth. This moment is unique and does not depend on location, and in certain circumstances it coincides with a solar eclipse.



In lunar calendars, a lunar month is the time between two identical syzygies (new moons or full moons). The use of the lunar month varies by which culture has utilized the method, the main difference being when the "new" month begins.


Solar eclipse (Wikipedia)

As seen from the Earth, a solar eclipse occurs when the Moon passes between the Sun and the Earth, and the Moon fully or partially blocks the Sun. This can happen only during a new moon, when the Sun and the Moon are in conjunction as seen from Earth. In a total eclipse, the disk of the Sun is fully obscured by the Moon. In partial and annular eclipses only part of the Sun is obscured.

If the Moon were to be in a circular orbit close enough to the Earth and in the same orbital plane, there would be total solar eclipses every single month. However, the Moon's orbit is angled at more than 5 degrees to the earth's orbit around the sun (see ecliptic) so its shadow at new moon often misses the Earth. The very reason why the Earth's orbit is called the ecliptic plane is because the Moon's orbit must cross this in order for an eclipse (both solar as well as lunar) to occur. Also, the Moon's actual orbit is elliptical, often taking it too far away from the Earth so that its apparent size is not large enough to block the Sun totally. So the orbital planes cross each year at a line of nodes resulting in at least two, and up to five, solar eclipses occurring each year; no more than two of which can be total eclipses. Total solar eclipses are nevertheless rare at any particular location because totality exists only along a narrow path on the Earth's surface traced by the Moon's shadow or umbra.

An eclipse is a natural phenomenon. Nevertheless, in ancient times, and in some cultures today, solar eclipses have been attributed to supernatural causes or regarded as bad omens. A total solar eclipse can be frightening to people who are unaware of their astronomical explanation, as the Sun seems to disappear during the day and the sky darkens in a matter of minutes.

As it is dangerous to look directly at the Sun, observers should use special eye protection or indirect viewing techniques. People referred to as eclipse chasers or umbraphiles will travel to remote locations to observe or witness predicted central solar eclipses.


Lunar eclipse (Wikipedia)

A lunar eclipse occurs when the Moon passes behind the Earth so that the Earth blocks the Sun's rays from striking the Moon. This can occur only when the Sun, Earth, and Moon are aligned exactly, or very closely so, with the Earth in the middle. Hence, a lunar eclipse can only occur the night of a full moon. The type and length of an eclipse depend upon the Moon's location relative to its orbital nodes. The most recent total lunar eclipse occurred on December 10, 2011. The previous total lunar eclipse occurred on June 15, 2011; The recent eclipse was visible from all of Asia and Australia, seen as rising over Europe and setting over Northwest North America. The last to previous total lunar eclipse occurred on December 21, 2010, at 08:17 UTC.

Unlike a solar eclipse, which can only be viewed from a certain relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of the Earth. A lunar eclipse lasts for a few hours, whereas a total solar eclipse lasts for only a few minutes at any given place, due to the smaller size of the moon's shadow. Also unlike solar eclipses, lunar eclipses are safe to view without any eye protection or special precautions, as they are no brighter (indeed dimmer) than the full moon itself.




.

No comments:

Post a Comment