Early on the morning of January 31, North Americans will be treated to, not one, not two but three coinciding lunar events, which the National Aeronautics Space Agency (NASA) is referring to as a ‘lunar trifecta’, or the ‘super blue blood moon’.
The phrase ‘super blue blood moon’ is basically the combination of the terms supermoon, blue moon, and blood moon – three different cosmic phenomena, involving earth’s only natural satellite, happening at the same.
For a better understanding, let’s look at each of these space events separately.
What’s a Supermoon?
Also known as the Beaver moon, a supermoon is nothing but an infrequent occurrence when the moon’s proximity to the earth is at its maximum, making it appear relatively larger and brighter in the night sky.
According to scientists, a supermoon occurs because of the elliptical shape of the moon’s orbit around our planet. As the moon goes around the earth along the oval-shaped orbit, it has to pass through points that are closest and farthest from earth, known as the perigee and apogee, respectively.
So, a supermoon occurs when the moon is in the perigee of its orbit.
Calling it a supermoon, however, is kind of exaggerated because the difference in the size of a perigee full moon and a normal full moon, as it appears to us, is marginal. If you didn’t know a supermoon was happening, you’d probably be as much impressed with it as you would be with any other full moon.
“The differences between an ordinary full moon and a ‘supermoon’ are so trivial that the phrase ‘supermoon’ is essentially meaningless for the general public,” Dr. Jay Pasachoff, an astronomer at Williams College in Williamstown, Massachusetts, told NBC News MACH in an email. “I note that the Earth was closest to the sun on its annual orbit on January 4, as it is every year — so we could have called that day a ‘supersun.’ Did you notice that the sun was brighter than usual? Of course not.”
American astrophysicist, cosmologist, author, and science communicator Neil deGrasse Tyson’s pizza analogy is the best way to explain the unnecessary hype behind a supermoon.
“If you have a 16-inch pizza, would you call it a super pizza compared with a 15-inch pizza?” deGrasse once asked on the StarTalk radio program.
It’s a well-known fact that the moon affects the tides on earth. A full moon brings higher than normal tides during the12 hour high tide cycle. Similarly, during the low tide period, the tides are lower than usual.
However, during a perigee moon, high tides are at their highest and low tides at their lowest.
What’s a Blue Moon?
A Blue Moon can be described as a relatively rare lunar phenomenon when we get to see an additional full moon over a given time period.
However, there are two explanations of the Blue Moon – the seasonal blue moon and the monthly blue moon.
The third full moon in a season of four full moons is a seasonal blue moon, which according to scientists happens once in 2.7 years, on an average.
The newer and more popular definition of the blue moon is the occurrence of two full moons in one calendar month.
By the way, the name is in no way associated with the color of the moon.
What’s a Blood Moon?
A lunar eclipse occurs when the earth’s shadow falls on the surface of the moon, and this can happen only when the sun, earth and moon are aligned together, with the earth between the other two.
When the three heavenly bodies are in perfect alignment, the earth’s shadow covers the entire moon in what we call a total lunar eclipse. During this phase, refracted light through the earth’s shadow gives the moon a reddish tint, giving rise to the nickname, ‘blood moon’.
In short, blood moon is another name for total lunar eclipse.
A partial eclipse takes place if only part of the earth’s shadow falls on the moon.
Why is the Jan. 31st event being called a ‘super blue blood moon?
On January 31st, the moon will be at the perigee of its orbit and hence, as explained above, closest to earth than any other point in its orbit, making it a ‘supermoon’.
And, because it’s going to be the second full moon this month, it will also be a ‘blue moon’ according to the newer definition of the phenomenon.
Lastly, the sun, earth and moon will be at the exact alignment needed for a total eclipse, causing the moon to appear somewhat reddish, giving us our ‘blood moon’.
And that gives us our ‘super blue blood moon’ – the ‘lunar trifecta’.
“The Jan. 31 full moon is special for three reasons: it’s the third in a series of ‘supermoons,’ when the Moon is closer to Earth in its orbit — known as perigee — and about 14 percent brighter than usual,” explains NASA. “It’s also the second full moon of the month, commonly known as a ‘blue moon’.”
“The super blue moon will pass through Earth’s shadow to give viewers in the right location a total lunar eclipse. While the Moon is in the Earth’s shadow it will take on a reddish tint, known as a ‘blood moon’.”
What time will the eclipse take place?
Wednesday’s lunar eclipse will begin at 3:48 am Pacific Time, reaching totality at 4:51 am PT, which will last until 6:05 PT.
Where can the ‘super blue blood moon’ be best viewed from?
While the ‘super blue blood moon’ will be visible in North America, Alaska and Hawaii before sunrise at the given times on Jan 31, viewers in the Middle East, Asia, Russia, Australia and New Zealand will be able to see the phenomenon after sunset the same day.
Those living on the West Coast and in the Midwest will be able to see the eclipse in its totality provided the skies are clear of clouds. East Coast residents, however, will be able to see only a partial eclipse before the moon sets that day.
“For the [continental] U.S., the viewing will be best in the West,” said Gordon Johnston, Program executive at the NASA headquarters in Washington. “Set your alarm early and go out and take a look.”
“Unfortunately, eclipse viewing will be more challenging in the Eastern Time zone,” Johnston added. “The eclipse begins at 5:51 a.m. ET, as the moon is about to set in the western sky, and the sky is getting lighter in the east.”