Tonight – September 30, 2016 – you probably won’t see the moon because it’s at the new moon phase. Depending on where you live worldwide, this new moon is either the second of two new moons in September 2016, or the first of two new moons in October 2016. The second of two new moons in a single calendar month is sometimes called a Black Moon.
A new moon, by the way, is just a moon that’s traveling more or less between the Earth and sun. New moon is part of every monthly orbit of the moon. Black Moon is just a name, like Blue Moon, or Harvest Moon, or any moon name (although nearly all refer to full moons). It doesn’t mean the moon is literally black, although the moon isn’t shining for us now either. Because it’s between the Earth and sun, the moon’s lighted side faces away from us now, and the moon is traveling across the sky with the sun during the day.
The moon turns new on October 1 at 0011 Universal Time. Translate to your time zone. Although the new moon happens at the same instant all over the world, the clock time varies by time zone. At our U.S. time zones, the new moon comes on September 30, at 8:11 p.m. EDT, 7:11 p.m CDT, 6:11 p.m MDT and 5:11 p.m PDT. So, for our part of the world, the upcoming new moon on September 30 counts as the second of two September 2016 new moons.
For the world’s Eastern Hemisphere, where the moon turns new on October 1, the upcoming new moon is the first of two October 2016 new moons.
In another day or two, the moon will appear as an extremely slender waxing crescent in the western sky after sunset, to mark the birth of the Jewish New Year 5777 A.M. and the Muslim New Year 1438 A.H.
The last Black Moon (second new moon in one calendar month) happened on March 30, 2014, and will next take place on August 30, 2019.
A Black Moon is also defined as the third of four new moons in one season. That kind of Black Moon will happen in the year 2017, to stage a total eclipse of the sun on August 21. It’ll be the first total solar eclipse to sweep across the mainland United States from the Pacific Coast to the Atlantic Coast since the year 1918.
A Black Moon can also be regarded as a calendar month having no new moon or no full moon whatsoever.
February is the only month where it’s possible to have no new moon or no full moon. The last time no new moon fell in February was in 2014, and the next time will be in 2033. In both 2014 and 2033, the absence of a February new moon gives rise to two new moons in January and two new moons in March.
No full moon will occur in February 2018, providing two January full moons and two March full moons in 2018. The second full moon in one calendar month is often called a Blue Moon.
This time around, in 2016, it’s either two new moons in September 2016 or October 2016, depending on your time zone. The second new moon in one calendar month is sometimes referred to as a Black Moon.
Bottom line: A Black Moon is the second of two new moons in a single calendar month. Whether you have one depends on your location on the globe. The Western Hemisphere has a Black Moon in September 2016. The Eastern Hemisphere has a Black Moon in October 2016.
Bruce McClure has served as lead writer for EarthSky's popular Tonight pages since 2004. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also writes and hosts public astronomy programs and planetarium programs in and around his home in upstate New York.