No one who is alive today will ever see anything similar, and the last time this extraordinary phenomenon took place was in 1866.
On January 31st there will be a rare coincidence of astronomical phenomena: a lunar eclipse, a super moon, a blue moon and a blood moon.
The blue blood superluna will be visible primarily from western North America through the Pacific to eastern Asia.
What are the characteristics of the astronomical phenomena that will coincide on January 31?
The term refers to a Moon that is full when it is at the closest point in its orbit around the Earth.
“The orbit of the Moon is very long and sometimes when the Moon is full it looks like it is close to us,” Mexican scientist Francisco Diego , professor of astronomy at University College London or UCL, part of the University of London.
“Of course that happens every month, that the Moon approaches and moves away from us following its orbit, but if the approach coincides with the full Moon it is called a Super moon“.
The orbit of the Moon is elliptical, and one side (apogee ) is about 50,000 km farther from Earth than the other closest (perigee ).
“When the Moon looks 10 to 15% larger than it would be a smaller one, the change is considerable and can be seen with the naked eye,” said Diego.
The super-moon on January 31st will be the third of what NASA calls a trilogy of superlunas , since the phenomenon also took place on December 3rd, 2017 and January 1st, 2018.
“The super-moon will also be the second full moon that we have in January,” said Diego.
“It’s about a month with two full moons and when that happens it’s called blue moon.”
On January 31st the Earth, the Sun and the Moon will align, giving rise to a total lunar eclipse.
“The full Moon will coincide at the moment when the Moon enters the shadow of the Earth producing an eclipse.”
In North America the eclipse will be visible before dawn on January 31st 2018.
It may also be observed in Asia, Australia, New Zealand and as far as eastern Russia.
In much of South America, Africa and Western Europe the total eclipse will not be visible.
Observers of the eclipse will see a large reddish moon , known as the “blood moon”.
“The color of this Moon during a total eclipse of the Moon is due to the atmosphere of the Earth, ” explained Diego.
“If we were on the Moon at that time we would see that the Earth passes in front of the Sun. The Earth looks like a dark disk, but remember that the Earth has an atmosphere and the light that passes through the atmosphere that goes to the Moon deviates”.
“The red part of the light reaches the moon, if we were on the moon we would see the same color as a sunset, but in this case it would be a sunset that would look like a red ring around the Earth and that is the light that comes to illuminate the Moon and that’s why it looks red. “
The scattering of light is what also explains red sunsets on Earth. And this phenomenon does not have to do with the distance that the light must travel, but with the angle with which the Sun’s rays reach us.
“In the case of red sunsets, what happens is that there are molecules in the Earth’s atmosphere, mainly nitrogen, water, oxygen, which are molecules that disperse blue light, so the sky looks blue during the day.”
“When the Sun is hidden or before the Sun rises, the red light dominates at that moment because it is the light that traverses the atmosphere most easily.”
The next time the phenomena of this December 31st, 2018 coincide, it will be 19 years, on January 31st, 2037.