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Why We’re Not Calling May’s Full Moon A Supermoon

Why We’re Not Calling May’s Full Moon A Supermoon

There’s a lot of talk of “Supermoons” these days. And in 2020, we had 2 already, and April’s Full Pink Moon, which happened on April 7th at 10:35 p.m. EDT, was our largest and last Supermoon of 2020. Some media outlets are calling May’s full Moon a Supermoon, but it falls short to earn the moniker (see below). But what is a Supermoon, what causes it, and how is it different from a regular full Moon?

First, What Is A Supermoon?

Supermoons are caused by the shape of the Moon’s orbit, which is not a perfect circle, but an ellipse, or oval, shape. The Moon orbits the Earth once each month, and each month, it reaches a point farthest from the Earth, called apogee, and a point closest to the Earth, called perigee.

According to how most people define a Supermoon, it occurs when the Moon is at least 90% of the way to its perigee position at the same time it is in its “full” or “new” phase. An extreme perigean Supermoon is when a full or new Moon happens at the same time the Moon is at perigee.

When we have a Supermoon, the Moon can appear as much as 14% larger and 30% brighter than a normal full Moon.

Learn all about “Moon Illusion” here.

Why New And Full Phases?

The reason these two Moon phases are singled out is because each of them means that the Sun, Earth, and Moon are in alignment. When the Moon is full, it sits exactly on the opposite side of the Earth from the Sun. When the Moon is new, it sits between the Earth and the Sun. In both cases, the gravitational pull from these two bodies—the Moon and the Sun—combine to create higher-than-normal tides, called “spring tides,” on Earth. When the Moon is also at perigee at this time, the effect is magnified into what is called a “proxigean spring tide.”

Of course, a new Moon at perigee isn’t very exciting to look at because in the new phase, the Moon does not reflect the Sun’s light, so it is invisible to the naked eye. So, understandably, full Supermoons get all the attention.

What’s In A Name?

We’ve heard from many of our readers on social media that they’re tired of hearing the term “Supermoon” so often. “It seems like every full Moon is a Supermoon!” The term became popular in March 2011 when the Moon’s perigee brought it to 221,565 miles of Earth; within 127 miles of the absolute closest that it can come (the absolute closest the Moon can come is 221,438 miles from Earth; an exceedingly rare occurrence).

In actuality, Supermoons should only be applied to “extreme” perigees, in which the full Moon approaches a distance of 221,472 miles or less. Between the years A.D. 1500 to 2500, this condition is met only 14 times, or on average once about every 71 years. The last time the full Moon came this close to Earth was January 15, 1930 (221,454 miles) and the next time will be on December 6, 2052 (221,469 miles).

But if you follow the 90% rule noted above, you can have as many as three—and on some occasions even four or five—Supermoons in a single year! Here at Farmers’ Almanac, however, we don’t like to “water down” the term and believe that a full Moon is truly a Supermoon when the full phase coincides (or very nearly so) with its closest perigee for a given year. Which happens once. However, we realize that many do enjoy the “Supermoon” terminology and want to celebrate Supermoons more often, so we usually bring attention to two of the closest Moons in the year.

Not All Supermoons Are Created Equal!

Just as the Moon’s orbit isn’t a perfect circle, it also varies slightly from month to month and year to year. Its perigee during one month may be slightly farther from the Earth than its perigee the next month. 

In 2020, we had two Supermoons: One in March and one in April.

March’s Worm Moon:

  • Moon turned 100% full on March 9th at 1:48 p.m. EDT
  • Moon at perigee on March 10th at 2 a.m. EDT – Distance from Earth: 221,903 miles

April’s Pink Moon:

  • Moon at perigee on April 7th at 2 p.m. EDT – Distance from Earth: 221,772 miles
  • Moon turned 100% full on April 7th at 10:35 p.m. EDT

Is May’s Flower Moon a Supermoon? 

  • Moon at perigee on May 5th at 11 p.m. EDT; Distance from Earth: 223,479 miles
  • Moon turns 100% full on May 7th at 6:45 a.m. EDT; Distance from Earth: 224,432 miles

Perigee comes 31 hours and 45 minutes before the Moon turns full. When it does turn full on May 7th, it will be another 935 miles farther away.

April’s Moon was 1,707 miles closer than May’s Moon will be when it’s 100% full. And in April, perigee occurred a mere 8 hours and 35 minutes before it turned full. So as you can see, April’s full Moon was the “true” Supermoon of 2020, with March’s Moon being a runner-up.

Many people speculating that extreme Supermoons can cause natural disasters such as earthquakes, volcanoes, and tsunamis. But most astronomers dismiss this line of thinking, though, arguing that the 2,000-mile difference — less than 1% of the Moon’s total distance from the Earth — is minimal in the grand scheme of things and unlikely to cause much disruption on Earth, beyond the usual perigean spring tide.

Regardless of what you believe about a Supermoon’s impact on Earth, or what you call it, one thing is certain: if the sky is clear, the view of the rising Moon will always be amazing, so get outside and enjoy it!

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  • youjizz says:

    The supermoon may look especially large to you, however, if it’s very close to the horizon. But that has nothing to do with astronomy and everything to do with how the human brain works. This effect is called the “moon illusion” and may arise from at least a couple of different things. Scientists suggest that perhaps the brain is comparing the moon to nearby buildings or objects, or perhaps our brain is just wired to process things on the horizon as bigger than things in the sky.

  • nicole holcomb says:

    I haven’t seen any thing kind of like that here in alabama lmao 🙂

  • jenny says:

    I saw it okay last night in Australia. Very bright, couldn’t see any significant difference in size.

  • Kim says:

    Awesome Moon,which I enjoy.It appeared brighter,not bigger,here in Maine.I saw it & took pics,which I posted.Thanks,I follow the Moons dates,names,& meanings!

  • jenny says:

    Will we get the same effect here on the other side of the Earth? I’ll certainly be looking out for it anyway. Thanks for that info.

  • ray crannell says:

    guess i miss supermoons in the pass i’ll see this one i hope!
    does it have effect on the weather?

  • Donna says:

    We have an “AWESOME” God and he sends us beautiful presents to enjoy. Hope we can see the moon in Indiana…waiting.

    • Angie says:

      In 2011 God was tolerating us. 2019-2020…let’s just say it’s time we get some punishment for our bad behavior. God is some kind of pissed off at the moment

  • Mr.Bill says:

    very kool just what i needed to brighten up this long cold winter thanks.

    • Angie says:

      If you only knew then what you know now lol. Who would of EVER thought the entire world would be hiding from or quarantined from the COVID-19 global pandemic. I’ll see it on Tuesday, from the safety of a wide open field

  • The Occupant says:

    Everyday there are awesome wonders of God. Some days are more AWESOMER 🙂

  • Andrew Grasso says:

    Thanks for posting this article for me Jaime!

  • Beverly De Fronzo says:

    Wow! What an awesome Birthday present I cannot wait to see it! Hope the weather cooperates!

  • midnghtldy says:

    Would love to be sitting on a beach in Hawaii gazing at a moon similar to the one in the above photo. Also I agree with Willow, that Our God does give us some very amazing sites to enjoy.

  • Richard says:

    This is very interesting and if the weather will cooperate I will be taking pictures and see how it looks, also will possibly post them…

  • Dee says:

    @Willow, you said it all!!!!!

  • Willow says:

    Good morning all! Wouldn’t you love to sit on a stump and gaze at a moon looking like the one in the photo for this article?! WOW! Our God gives us such Awesome beauty!

  • terri says:

    thanks, very interesting…learn something new EVERYDAY..

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