The Moon is always the same; what changes are the names – 09/03/2023 – Sidereal Messenger

At a time when the sky needs to compete (and almost always loses) with intense urban light pollution and when communication vehicles need to seek clicks at (almost) any price, we have seen a proliferation of the disclosure of “rare” and “rare” astronomical events. spectacular” that, sometimes, leave those who see them wondering if they have problems with their eyesight.

Yeah, even those most disillusioned with astronomy tend to see the Moon in the sky frequently, and the said one repeats a more or less tedious cycle in its journey of 29.5 days through four phases, as it travels in its orbit around the Moon. Earth, and the planet advances a little more in its path around the Sun. Expecting something very rare to happen under these circumstances, common sense already says is wrong. But turns and moves try to convince us otherwise.

Let’s take the most recent example, the “Super Blue Moon”, which happened last Wednesday (30) and was celebrated in some corners of the internet as a rare event, of which the last example occurred in December 2009 and the next one, only in January 2037.

Do not get me wrong. The Moon was really beautiful and deserved to be admired. The full phase was reached at the same time that the natural satellite reached the perigee of its orbit – the closest point to Earth in a path that, as we know, is not perfectly circular, but elliptical. As a result, it was 14% larger and 30% brighter than when it is at apogee (the farthest point). For these showy characteristics, the phenomenon earns the nickname of Supermoon. But it’s not uncommon. It takes place three or four times a year. This, on the 30th, was the third in a row, of four. In September we will have another one.

Huh. And the talk that the next one is only in 2037? Enter the combination of the Supermoon (full phase close to perigee) with the Blue Moon which, surprisingly, has nothing blue. It’s just a nickname to refer to a second full moon that occurs in the same month. You see: if the lunar phase cycle takes 29.5 days, and most months are 30 or 31 days long, all that is needed for a month to have a Blue Moon is for the first full Moon to occur right at the beginning of the month . This isn’t wildly uncommon either, occurring on average once every two or three years.

Putting together the simultaneity of the two occurrences, we arrive at the “rarity” thing – which actually doesn’t deserve much attention, because it doesn’t imply something different to be seen in the sky. A Super Blue Moon is indistinguishable from a Super Moon, which itself is beautiful, but not that far removed from any other full Moon.

The most unusual and interesting phenomena involving the Moon are eclipses, which can be of the solar type (when the Moon blocks at least part of the solar disk) and the lunar type (when it transits behind the Earth’s shadow). And even these are not excessively uncommon, although they can be distinguished (as well as Supermoons) by specific characteristics such as distance from Earth to the Moon, duration of the phenomenon, etc.

It’s always really cool when the media draws the public’s attention to an astronomical event. But one must be careful and precise so as not to anesthetize or frustrate him with promises of spectacle or rarity that later turn out to be empty. The Moon is really beautiful, but for what it is – and it will remain the same as ever, no matter what people say.

This column is published on Mondays in the printed version, in Folha Corrida.

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