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At the end of January, media around the world were excited about the "Blue Moon of Blood". From now on, it is the exceptionally long lunar eclipse of this Friday that engulfs the crowds. But do these lunar phenomena really deserve so much attention?
A "Super Moon" three to four times a year
A "Super Moon" occurs when the Earth's natural satellite is at its perigee, that is to say closer to our planet. It then appears larger and brighter than at its peak, that is, at its furthest point from the blue planet.
The perigee / apogee cycle is repeated every month. We speak of "super moon" when the moment of the perigee corresponds to that of the full moon, offering magnificent images. It will be necessary to wait until March 19th, 2019 to observe again a super Moon. But the phenomenon will be repeated three times during the year.
The "Blood Moon", once a year
Also called "Red Moon", it is actually about a total lunar eclipse. The blue planet is then placed between the Sun and the Moon. The satellite is not, however, fully immersed in the dark. The Earth's atmosphere acts as a prism and reflects some of the Sun's light. However, it only allows the color red, giving the moon a bloody look.
The Sun, the Earth and the Moon are perfectly aligned only once a year, the rest of the time, the eclipse is only partial.
rare combinations the same night
This 27th of July, the Blood Moon coincides with the apogee of the satellite. Now, the further the Moon is from the Earth, the longer the eclipse is: the satellite takes longer to cross the shadow zone of the Earth. In all, the phenomenon will last 1:43.
The last time mankind experienced such a long eclipse was May 31, 318, 1700 years ago. The phenomenon is very rare, but will not give as beautiful photographs as the super Moon of blood: the satellite will be very small in the sky.
The "Blue Moon", a false astronomical phenomenon
spends 29.5 days between two full moon sequences. During a year, this phenomenon is therefore reproduced in principle on 12 occasions, approximately one per month. A moon is called "blue" when it comes to the second in the same month. This year, as the full moon arrived on January 2, it was logical that January had an extra full moon. It is only a coincidence of timing. Moreover, the "blue moon" does not affect the appearance of our natural satellite. Every three years, one year counts 13 full moon sequences, not 12. This was the case in 2015, 2012 and 2009.
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