We’re seeing media hype about a “Black Moon” on Friday, September 30, 2016. Don’t get too excited. It’s just a nickname WHAT IS A BLACK MOON?
“Black Moon” is not an astronomical term. In fact, if you ask a sample of astronomers, both professional and amateur, very few will have even heard of it. It’s not even a particularly widely known folklore thing.
As for its definition, some people (like some witches groups) say it’s a “black Moon” if:
- There is a New Moon twice in the same month (as is the case for the September 30). It’s similar to the Blue Moon, which has become a common term for the secondFull Moon in a month.
- There are NO New Moons in a month. That could only happen in February, and thus is kind of rare, meaning once every 5 to 10 years.
- The phrase might also simply refer to every New Moon, since we’re then seeing the Moon’s dark or black side.
- The phrase is also sometimes applied to mean the third New Moon when there are four in a season, which is actually one of the definitions of a “blue Moon” when the same thing happens to a Full Moon.
There is no astronomical significance in a Black Moon. Nothing happens, except the usual New Moon absence of any Moon in the sky, plus the stronger so-called “spring” tides we get for a few days around every Full Moon and New Moon.
If you feel free to use any of the definitions, you’ll get a Black Moon at least once a year, and sometimes twice. For example, last year on Feb 18 we had the 3rd New Moon out of four that season, so that was a Black Moon according to that definition.
Interestingly, next Friday, September 30 we’ve got the second New Moon this month, but only for people in the Western Hemisphere (which includes North America). In Europe and points east from there, the New Moon is after midnight and hence on October 1 and, sorry, no bingo for them. They’ll just have to be patient and wait another month.
Yes, it’s just scheduling, folks. The chances of getting two New Moons in a single calendar month happen about every 32 months.
WHAT WILL YOU SEE?
Uh, not much. During the New Moon phase, the Moon seems to disappear from the night sky.
Remember, there are four quarters of the Moon or Moon phases. You all know the “Full Moon” when the entire disk of the Moon is illuminated by the Sun (because they are on the opposite sides of the sky).
In contrast, the “New Moon” has its dark side facing us. It’s not reflecting any of the Sun’s light (because the Moon is lined up between the Earth and Sun).
Interestingly, folks who live in other parts of the world Europe, Africa, Asia, and Australia get their “Black Moon” on Halloween! Yep, they get a New Moon on October 1 and then again on October 30. A black sky devoid of Moonlight could be kind of spooky!
For those of us in North America, the good news is that this weekend brings darker skies for excellent stargazing (since the Moon’s light won’t drown out the stars).