Contrary to popular belief, the Moon will not be blue. This term is used when it comes to the second full moon in the same month. On the other hand, it will be “super”: a double phenomenon which is rare.
You will have to raise your head to the sky on the night of Wednesday to Thursday to observe an astronomical event: a “super blue moon”. A phenomenon that only happens on average every ten years, or even 20 years, according to the American space agency, NASA. The next will occur in 2037.
Contrary to what its name may suggest, the star will not turn blue. The name “bleu” comes from the English expression “once is a blue moon” used to describe a situation that happens only rarely, as we would say in French “tous les thirty-six du mois”.
The term blue moon is therefore used when a full moon appears twice in the same month, every two or three years. The lunar cycle being 29.5 days, a full moon that occurs at the very beginning of the month is often followed by a second full moon at the very end of the month.
The star of the night will even be slightly more orange than usual, underlines Futura-sciences, “a phenomenon similar to that of sunsets” because it will be low on the horizon. Red, orange and yellow wavelengths will pass more than blue and violet light scattered by air particles.
A slightly larger and brighter Moon
This Moon will therefore not be really blue, but will be “super”. That is, it will be at the closest point in its elliptical orbit to Earth, about 363,000 kilometers away, and will therefore appear 14% larger, and 30% brighter than usual. If this phenomenon is not exceptional, and the difference in size is not obvious, it remains pleasant to admire.
“This corresponds to the difference in size between a 25 cent coin and a 5 cent coin”, notes NASA, specifying “that about 25% of full moons are supermoons, but only 3% of full moons are blue moons”.
To take advantage of this rare celestial combination, it is advisable to move away from any light pollution generated by cities. Around the globe, the Moon will appear full at 1:35 a.m. GMT, or 3:35 a.m. Paris time. It will be visible all night, until dawn. If the eyes are enough, the most equipped can bring their binoculars or their telescopes. Hoping that the clouds do not come to hide this spectacle.
Source: BFM TV