Late last year, we were treated to four consecutive supermoons, where the moon is the biggest and brightest that it can possibly be in the night sky. Have you ever wondered what it’s called when the opposite happens? There is a name for it, and it’s happening this weekend — the emergence of the black moon.
The term black moon isn’t an official term, but rather a nickname for when a new moon fulfills certain conditions. Typically, each season has three new moons just like it has three full moons. However, when the stars align — pun intended — there is an extra cycle squeezed in. When this happens to full moons, it’s referred to as a «seasonal blue moon,» and this happens to a new moon, it’s called a black moon.
The weekend of Aug. 22 is such an occurrence. The first new moon of the summer came relatively early, on June 25, followed by the next one on July 24. The final new moon of the season comes on Sept. 21, which is the day before summer officially ends. Since there’s an extra new moon, the third new moon in the set of four is referred to as the black moon, which means August’s moon gets the distinction.
Two types of black moons
According to Dr. Shannon Schmoll, manager of Michigan State University’s Abrams Planetarium, a black moon is essentially the same as a blue moon, but for new moons instead of full moons. Thus, the same rules apply to both.
«A black moon tends to have two common definitions,» Schmoll tells CNET. «The less cumbersome one is the second full moon in a month. Because thelunar cycle is a bit shorter than most months, every once in a while, there will be a full moon at the very beginning and very end of amonth.»
Since the solar cycle is 29.5 days, as Schmoll notes, this can happen, and it does soabout once every 29 months.
The next occurrence of that type of blackmoon is slated for August 2027, when new moons will appear on Aug. 2 and Aug. 31. The last time this happened was in the spring of 2023.
«The other definition is the third full moon in a season with four,» says Schmoll. «So, a season here is the time between an equinox and a solstice. Becausethat is three months, we typically get three moons in that time. Every once in a while, we get four, and the third one is the ‘extra’ one. «
This occurs once every 33 months and is the rarer of the two types of black moons, making August’s new moon a little extra special. The next time this type of black moon is slated to happen is in summer 2028, when June and September’s new moons will take place during the summer once again, like they did this year.
For reference, blue moons are also fairly rare. The next blue moon is coming in May 2026 on the 1st and 31st of the month.
In the grand scheme, though, Schmoll says that these instances are quirks of our calendar system and «there isn’t anything astronomically significant about it» aside from it being a fun little coincidence.
You can’t see it, and that’s OK
We see the moon because it reflects light from the sun. During a new moon, our closest celestial neighbor is hidden behind the Earth, so sunlight can’t reach it. That means you won’t be able to see this rare celestial phenomenon even if you try, so for once, we recommend not bothering to look for it.
Per Schmoll, the only way to see a new moon is if there’s a solar eclipse when it slips in front of the sun.
However, there are other ways to enjoy a new moon: the moon is often cited as one of the most common and unavoidable sources of light pollution, making it harder to find things in the night sky. The Perseids meteor shower had its peak during August’s full moon, which made the more dimly lit meteors more difficult to see, even if you left the city and suburbs to get a darker sky.
With this year’s black moon, stargazers will get one additional night this summer of serene, moonless darkness in the night sky. This will give enthusiasts another great chance to spot six planets in the sky for the last six-planet parade we’ll see for a few years, and for photographers in the northern hemisphere to get some outstanding shots of the Milky Way galaxy. Since Perseids ends on Aug. 23, there’s also a chance you may see one of the final shooting stars from that meteor shower.
So, if you’ve been waiting for the darkest possible night to see some stars, this weekend is a great opportunity thanks to this year’s black moon.
