A rare celestial will mark January 31, when a total lunar eclipse will occur at the time of a full “blue super moon of blood, even as our natural satellite will be almost closer to Earth, producing what astronomers call the “blue super moon of blood”.
If the weather conditions are favorable, it will offer Wednesday a breathtaking spectacle.
“We will be able to see, during the eclipse, the reflections on the lunar surface of all the sunrises and sunsets on Earth,” says Sarah Noble, a NASA scientist.
This phenomenon results from a “rare alignment of these three astronomical cycles,” says Jason Aufdenberg, assistant professor of astronomy at the Aeronautical University of Embry-Riddle, Florida.
The term “blue moon” means a second full moon in one month, a phenomenon that occurs on average every two and a half years.
The eclipse will also occur only 27 hours after the moon reaches its orbital point closest to our planet, called the perigee, producing almost a “super moon,” say the astronomers.
The Moon moves at an average distance of 384 400 kilometers from the Earth and will be on January 31 at 359 000 kilometers, very close to its perigee (356 410 km). At its peak, the lunar orbit reaches 406,000 km.
“We have a lot of great moons and lunar eclipses but these two phenomena do not often coincide with a blue moon,” says Jason Aufdenberg.
The last similar celestial rendezvous occurred on December 30, 1982, and had been visible in Europe, Africa, and western Asia.
For North America, one must go back to 152 years, to March 31, 1866 and before that to May 31, 1341, according to the annals.
Such an eclipse – when the Moon passes into the cone of shadow produced by the Earth – is also called “Blood Moon” because the star does not become completely black, part of the sunlight, reflected by the atmosphere terrestrial, indirectly reaching the lunar surface.
Some solar rays are also filtered, which produces a reddish or coppery reflection on the moon. This phenomenon occurs when it is at its orbital perigee.
In its orbital extremes, the full Moon can appear up to 14% larger and 30% brighter at its perigee than when it is at its peak.
The “Super Blue Blood Moon” will be observable only in Asia, the Pacific Ocean, Russia, western North America and partially in the east.
On the east coast of the United States, the moon will begin to enter the shadows of Earth Wednesday at 5:51 am, says NASA on its website.
Moon sometimes really blue
The darkest part of the eclipse, with reddish hues, will be visible from 6:48 am, less than half an hour before sunrise.
But observers in the western United States and Canada, where it will still be dark, will be in the best position to observe the eclipse throughout its duration, one hour and sixteen minutes in its entirety.
In California, for example, the phenomenon will begin at 3:48 am in the morning and the total eclipse at 4:51 am. The best observation period will be between 5 am and 6 am complete eclipse ending at 06:05, according to NASA which will retransmit the event on NASA’s website.
The next “Super Blue Blood Moon” is scheduled for January 31, 2037.
But astronomers are eagerly awaiting the total lunar eclipse of January 21, 2019, which will occur around midnight on the east coast and will be visible throughout the United States.
During a year, there may be a maximum of four solar eclipses and three lunar eclipses.
The use of “Blue Moon” in reference to this astronomical event “resulted from a blunder in the pages of Sky and Telescope dating back to 1946,” according to Kelly Beatty, a publisher of this American trade journal.
“The expression went around the world,” inspiring the public’s fascination, he says, even giving his name to a cocktail and a beer that is widely sold in the United States.
Before that, the formula “ounce in a blue super moon of blood” in English described an extremely rare event, specifies the expert.
But, he adds, in rare cases, the moon becomes really blue when volcanic eruptions, forest fires or dust storms throw tiny particles into the atmosphere.