Wednesday, February 18, 2015

Today's "Black Moon"

By Glenn A. Walsh
Reporting for SpaceWatchtower

The Earth's Moon has been given many names over the many millenia men and women have been looking at our planet's only major natural satellite. In addition to the many names given to the Full Moon for each month, by Native Americans, in more recent times “Blue Moon” and “Super Moon” have joined the lexicon.

Now the “Black Moon” joins the list. And, at the moment of the posting of this blog post, 6:47 p.m. Eastern Standard Time (EST) / 23:47 Coordinated Universal Time (UTC) on Wednesday Evening, 2015 February 18, we observe the most recent “Black Moon.”

As with the so-called “Blue Moon,” the “Black Moon” has more than one definition. The definition to describe today's “Black Moon” is the third New Moon phase in a calendar season which includes four New Moons. This is similar to the one definition of a “Blue Moon”: the third Full Moon phase in a calendar season with four Full Moons. And, of course, a “Black Moon” is described as black because this is the time the near side of the Moon (the only side of the Moon that can ever be viewed directly from the Earth) is not illuminated by the Sun.

So, the February Moon phase of New Moon (Lunation # 1140) occurs today at 6:47 p.m. EST / 23:47 UTC.

As most calendar seasons have three Full Moons, most calendar seasons also have three New Moons. However, by an occasional quirk in the calendar, this year Winter has four New Moons. A fourth New Moon occurs this Winter on March 20, just about 13 hours before the Vernal Equinox, the official beginning of the season of Spring!

As with the terms "Blue Moon" and "Super Moon," the term "Black Moon" is not an official designation and has no real astronomical significance. 

Other definitions used for a “Black Moon”:

  1. A month missing a New Moon or a month missing a Full Moon (in both cases, this can only happen in February).
  2. The second New Moon in a month with two New Moons (which can only happen in any month except February).

2015 February 18 is also significant for these reasons:

  1. As the Chinese use a lunisolar calendar, today's New Moon marks Chinese New Year.
  2. In the Christian calendar, today marks Ash Wednesday, the beginning of Lent, 46 days before Easter Sunday.
  3. Today marks the 85th anniversary of the discovery of the Planet Pluto, now designated Dwarf Planet 134340 Pluto, by Clyde Tombaugh at Lowell Observatory near Flagstaff, Arizona.
More on a "Black Moon":
Link 1 >>>
Link 2 >>>

More on a Lunisolar Calendar: Link >>>

More on the Chinese New Year: Link >>>

More on Ash Wednesday: Link >>>

More on Dwarf Planet 134340 Pluto: Link >>>

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.

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