The ‘blood moon’ of today July 27 can provide information on the hole in the ozone layer
Blood Moon 2018: The Earth will be placed between the sun and the moon on the night of July 27, giving rise to the longest lunar eclipse of the 21st century. The total phase of the phenomenon will begin at 9:30 p.m., Spanish peninsular time, and will last for 102 minutes since the moon will pass near the center of the earth’s shadow. During this phase, the satellite reflects a reddish hue that popularly gives it the name of a blood moon. Although the most striking aspect of the phenomenon is the spectacularity of its color, it is also useful for scientists to better understand the state of the Earth’s atmosphere, according to Miquel Serra, an astronomer at the Instituto de Astrofísico de Canarias (IAC).
When entering the moon in the shadow of the Earth, the logical thing would be that it was invisible from our planet. “We see it because the Earth’s atmosphere produces two effects on sunlight,” says the IAC expert. The first is the phenomenon of refraction, a curvature of the Sun’s rays that surround the Earth until it reaches the moon. The second is similar to what happens during a sunset. The atmosphere disperses the most energetic colors of sunlight, such as green and blue, so that only red rays reach the lunar surface. “The result is a moon illuminated with coppery tones, and it’s the most spectacular,” says Serra, who considers it “interesting and beautiful because the intensity of red is unknown until now,
The intensity of the red color of the Moon tells us about the state of the atmosphere
The color adopted by the Moon can be related to air pollution, but above all “can tell us about the general state of the atmosphere at a certain time,” says Miquel Serra. The reason is that, beyond the polluting particles, other factors intervene such as the presence of clouds or volcanic emissions in certain areas of the planet. “The volcanic particles make the reddish tone increase,” says Antonio Pérez, a scientific disseminator specialized in astronomy and space sciences. Therefore, the more there is in suspension the night of the 27th, the redder we will see the eclipsed moon, according to the expert.
In addition, a very interesting effect is that a lunar eclipse can report on the state of the hole in the ozone layer, which “seems to be related to a variation in the size of the Earth’s shadow,” says Serra. The IAC team to which the astronomer belongs will move to Namibia, where the phenomenon can be observed from beginning to end. From there they will calculate the color of the whole and take data of the size of the moon shadow, which “varies from eclipse to eclipse every two years,” says Miquel Serra.
The main reason that leads them to Namibia is, however, to retransmit on their website the eclipse with high-quality technology so that the public can observe the phenomenon from anywhere in the world. It will be done in collaboration with Sky.live.com, an online television specializing in the live broadcast of astronomical events, and can also be seen on the Online website.
Africa, the Middle East, and some Central Asian countries are the places where the eclipse will be completely visible. Australia can only enjoy the start and, South America, the end. Regarding Spain, it can be seen from the beginning of the total phase, which coincides with the departure of the Moon in Madrid, at 9:30 p.m., until the end of the phenomenon, at 23:13. Its maximum will be at 22:22, Peninsular time. As the beginning of the totality will coincide with the appearance of the Moon in the Iberian Peninsula, the satellite will be eclipsed in most Spanish cities from the beginning. For this reason, ” at a photographic level, it is going to be a quite unprecedented landscape, because we can see the moon coming out through the horizon completely eclipsed,” says Antonio Pérez.
The complete phenomenon will last 3 hours and 55 minutes if we take into account the twilight time, that is, the moment in which the moon passes through the clearest area of the Earth’s shadow. “We had been without a lunar eclipse for more than two yearsTotal visible from Europe and, although it will not be fully visible from Spain, you can see the end of the phenomenon, “says Miquel Serra, meaning that the first stage of penumbra cannot be seen in Spain, except for the Balearic archipelago, which The rest of the phases will be visible from the peninsula and from the Canary Islands, although the elevation of the satellite will be quite low, so Antonio Pérez recommends observing it from places that show the cleared horizon and adds that, although can be seen with the naked eye, a “binoculars or telescopes can help perceive certain forms.”
The lunar eclipse will almost coincide with the brightest night on the red planet in recent years, which will be that of July 28. “They are orbital questions of Mars that have no relation with the lunar eclipse”, stresses Antonio Pérez, “but both phenomena will give the next weekend a great astronomical interest”, he assures.