Look up tonight! The Super Blue Moon will be shining in the sky
Tonight's Full Moon is kind of rare, and then again, not so much.
A "rare" celestial event will be visible in the sky Monday night — a super Blue Moon. But is this actually as rare as we've been told?
The Full Sturgeon Moon rises on the night of Monday, August 19. This is not only a supermoon — a Full Moon that is closer and thus bigger and brighter than usual — but as the third Full Moon in a season of four Full Moons, this is also a Blue Moon.
We've seen this particular combination, a Super Blue Moon, not so long ago. In fact, it was just last year, at the end of August, that we saw a Super Blue Moon.
The Perigee Blue Moon of August 30-31, 2023, as imaged by NASA's Lunar Reconnaissance Orbiter. (NASA's Scientific Visualization Studio)
Or did we? Well, yes, we did, but also in a way, we also didn't, because there are actually two different types of Blue Moon.
Two Blue Moons?
So, a typical year sees 12 Full Moons, and in general, these occur once per month and three per season.
However, because the timing between Full Moons (29.5 days) doesn't match up with the length of our calendar months, the exact date of each Full Moon changes, month to month. This results in two different situations where it seems as though we have an 'extra' Full Moon. In both cases, we call this 'extra' one the Blue Moon.
The first type of Blue Moon is when we end up with two Full Moons in a single calendar month — one at the beginning of the month and a second at the end. This can happen during any month of the year except February. In the case of this 'calendar Blue Moon', not only are there two Full Moons in a single month, there are also a total of 13 Full Moons, instead of 12, for that entire year.
This is what happened in 2023, when we had a Blue Moon at the end of August.
The second kind of Blue Moon happens when the first Full Moon of a season occurs within a few nights of the start of that season. In that case, instead of the usual three Full Moons in the season, we will actually see four, with the third of those being the 'Blue Moon'. This is technically the original definition for the term, although the calendar Blue Moon has become more popular in modern times.
The four Full Moons of Summer 2024, including the Blue Moon on August 19-20, and the partial lunar eclipse on September 17-18. (NASA's Scientific Visualization Studio/Scott Sutherland)
As shown above, the first Full Moon of Summer 2024 fell on the night of June 21-22, just one day after the Summer Solstice. After that, the July Full Moon was on the night of the 20th-21st and the August Full Moon is tonight, on the 19th-20th. The final Full Moon of the season falls on September 17-18, several nights before the September 22 Autumnal Equinox.
Thus, with tonight's Full Moon being the third of the season, this is a seasonal Blue Moon.
Super Blue Moon
The last seasonal Blue Moon we saw was in August 2021, which is also not so very long ago. However, to be fair, that one wasn't a supermoon.
It's not exactly a scientific term, but a 'supermoon' occurs when the Moon is close to its closest approach to Earth when it reaches its Full (or New) phase.
Essentially, it's a bigger, and more significantly brighter Full Moon than normal.
DON'T MISS: Why is the 'Supermoon' so compelling to us?
So, the August 30-31, 2023 calendar Super Blue Moon was just last year. However, the last seasonal Super Blue Moon was over a decade ago, in August of 2013. Thus, we've had to go through three different seasonal Blue Moons to get to this one.
The next seasonal Blue Moon will be in May of 2027. However, we'll have to wait until August of 2032 before we see the next seasonal Super Blue Moon.
That makes tonight's Full Moon a member of a slightly more rare group, overall. So, if you have clear skies and a few moments to spare, be sure to look up to take in the splendor of this (slightly) rare event!
(Thumbnail courtesy NASA's Scientific Visualization Studio)
