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Hi Diana,
Well, this is a new one for me! But the "black" moon is apparently
the opposite of a blue moon. A "blue moon" is the term given to
the second full moon in a month. The "black moon" is the case
where there are two "new moons" in one month. During a new moon,
we can't see the moon because it is between the earth and the sun.
As with the blue moon, statistically you expect to have two identical
phases of the moon in a single month about every 2 1/2 years (whether
it is a full moon, first quarter, new moon or whatever). If there
are two identical phases then since they are separated by about
30 days, the first phase (new moon this month) will occur in
the first couple days of the month and the second phase (another
new moon) will occur in the last couple days of the month.
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