{"id":787425,"date":"2024-08-18T03:10:54","date_gmt":"2024-08-18T08:10:54","guid":{"rendered":"http:\/\/spaceweekly.com\/?p=787425"},"modified":"2024-08-18T03:10:54","modified_gmt":"2024-08-18T08:10:54","slug":"does-a-supermoon-have-a-super-effect-on-us","status":"publish","type":"post","link":"https:\/\/spaceweekly.com\/?p=787425","title":{"rendered":"Does a supermoon have a super effect on us?"},"content":{"rendered":"


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View at EarthSky Community Photos. | Jean-Baptiste Feldmann in Gleiz\u00e9, France, captured this image on August 30, 2023. Jean-Baptiste wrote: \u201cThe full supermoon appeared all red above the houses on the horizon, about 10 kilometers away. Her color was truly spectacular. I think I much prefer a red moon to a blue moon!\u201d We love red moons, too! Thank you, Jean-Baptiste!<\/figcaption><\/figure>\n

Next supermoon is August 19, 2024<\/h3>\n

The term supermoon<\/em> denotes a new or full moon that occurs at roughly the same time the moon is nearest the Earth in its monthly orbit. In fact, there are four full supermoons in a row in 2024. We\u2019re coming up on the first one, a seasonal blue moon supermoon. It\u2019ll fall on August 19, lighting up the nighttime sky from dusk to dawn. <\/p>\n

But sometimes people ask:<\/p>\n

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Does a supermoon have a super effect on us?<\/p>\n<\/blockquote>\n

Does a supermoon\u2019s gravity pull us harder?<\/h3>\n

Here\u2019s the important question for this discussion. <\/p>\n

Does the moon\u2019s gravitational pull vary with its distance? The answer is, sure, it does. The moon pulls least on Earth when farthest away in its orbit (apogee<\/em>, or farthest point from the planet). And it pulls most on Earth when closest to us (perigee<\/em>).<\/p>\n

But does that increased gravity matter to us as human beings? The answer is \u2026 no, it doesn\u2019t.<\/p>\n

And here\u2019s why. Gravity depends on two things. It depends directly on the masses of the two objects being gravitationally attracted. And it depends inversely on the distance between the two objects.<\/p>\n

So \u2026 \u201cinversely<\/em> on the distance between.\u201d That just means what we said at the top of this section. The moon pulls most strongly on Earth when closest to us. And it pulls least strongly when farthest away.<\/p>\n

But \u2026 \u201cdirectly<\/em> on the masses of the two objects being gravitationally attracted.\u201d The more massive the object, the greater the pull of gravity. The Earth and moon are both very massive. So they exert a large gravitational pull on each other. <\/p>\n

And that\u2019s why a closer moon can cause especially large ocean tides. Earth\u2019s oceans are very massive, too.<\/p>\n

But are you<\/em> very massive? No. Not compared to Earth\u2019s oceans. Consider an average 176-pound (80-kilogram) human being. The maximum difference on a person between a close moon and a distant moon is about 73 milligrams. And that is about 1\/14 the mass of an ordinary paper clip.<\/p>\n

If you factor in the solar gravity effect for a supermoon, or full moon closest to Earth, this effect may rise to about 110 milligrams. And that is roughly equivalent to about 1\/9 the mass of a paperclip.<\/p>\n

In either case, the effects are imperceptible, and far smaller than those encountered in other everyday situations, for example, being near a mountain or even near a large building.<\/p>\n

You can expect high tides near one<\/h3>\n

But, you might observe \u2013 like I said earlier \u2013 that an extra-close full moon causes higher-than-usual perigean tides. The tides are a very different situation from human beings. Tides work through what is called a differential gravitational effect<\/em>. Specifically, the force of gravity exerted on the part of the Earth opposite the moon (the far side of Earth, as seen from the moon) is slightly less than the force of gravity exerted on the part of the Earth directly beneath the moon (the Earth\u2019s near side, as seen from the moon) at any given time.<\/p>\n

Why? It\u2019s because there\u2019s an additional distance \u2013 about 8,000 miles \u2013 from one side of Earth to the other. The force of gravity weakens rapidly with increasing distance, producing the differential<\/em>.<\/p>\n

\"Large,
View at EarthSky Community Photos. | Kamala Venkatesh of San Diego, California, captured this image of the August 1, 2023, full moon, sometimes called a Sturgeon Moon. It was also a supermoon. Kamala wrote: \u201cIf you didn\u2019t see the Sturgeon supermoon, there\u2019s one coming up at the end of August.\u201d Thank you, Kamala!<\/figcaption><\/figure>\n

The Earth is more rigid than the oceans<\/h3>\n

The result of this differential gravitational effect of the moon is that our planet is stretched slightly along a line between the Earth and moon. The body of the Earth is fairly rigid, so it does not stretch much. However, the oceans are much more easily moved. Thus, the effect piles up water on either side of Earth. And these piles of water \u2013 created by the differential gravitational effect \u2013 are the tides. Note that, on average, the tidal effect is quite small. It raises tides only a few feet across an 8,000-mile-wide planet Earth.<\/p>\n

Technically, the same effect acts on your body as well, since one side is farther from the moon than the other. However, the difference in distance is on the order of one foot, rather than thousands of miles. Therefore, the differential is millions of times less, and the effect on a human body infinitesimally small and irrelevant.<\/p>\n

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About 3 or 4 times a year, a new or full moon coincides with the moon\u2019s closest point to Earth, or perigee. There\u2019s usually only a small difference \u2013 typically a couple of inches (or centimeters) \u2013 between these \u201cperigean spring tides\u201d and normal tidal ranges. But, at these times, if a storm strikes along a coastline, flooding can occur. Image via NOAA.<\/figcaption><\/figure>\n

Supermoons do get a lot of attention<\/h3>\n

Supermoons are important because they focus attention on the moon and the sky in general. But the bottom line is that any physical effects of supermoons<\/em> are not exactly super<\/em>. There is no reasonable evidence that they cause super disasters<\/em>. The effects that people may attribute to them are psychological rather than physical.<\/p>\n

There are several supermoons<\/em> this year and every year. To learn about supermoons in general try this EarthSky post: What is a supermoon?<\/p>\n

Enjoying EarthSky? Sign up for our free daily newsletter today!<\/p>\n

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View at EarthSky Community Photos. | Mickey Walters of Jamestown, Rhode Island, captured this image on August 1, 2023. Mickey wrote: \u201cSturgeon Full Moon from Narragansett Bay, overlooking Newport, Rhode Island.\u201d Thank you, Mickey!<\/figcaption><\/figure>\n

Can you notice a difference in the size of supermoons?<\/h3>\n

So, does the change in distance between the moon\u2019s farthest and closest points make it appear smaller and bigger? In fact, the full supermoon can appear as much\u00a0as 14% larger in the sky and 30% brighter to our eyes than at minimum size and brightness.<\/p>\n

However, these changes do not come all of a sudden from month to month. But, without anything with to compare them with, the changes in the moon\u2019s size or brightness are hard to quantify by simple observation. To notice the difference, you would need to see the apogean<\/em> (smallest) full moon and the perigean<\/em> (largest) full moon side by side.<\/p>\n

For most of us, it\u2019s only possible through photography or through some form of direct measurement. Although, careful observers have claimed to be able to discern a supermoon\u2019s extra large size with the eye.<\/p>\n

\"On
View at EarthSky Community Photos. | Tameem Altameemi of Dubai, United Arab Emirates, made this composite image and wrote: \u201cI photographed the moon today, August 1, 2023, in perihelion, at a distance of 357,550 km. And I photographed the moon on February 5, 2023, when it was at aphelion 401,751 km. I took them with the same telescope and camera, showing the difference between them.\u201d Thank you, Tameem!<\/figcaption><\/figure>\n

Where did the term supermoon originate?<\/h3>\n

An astrologer, not an astronomer, coined the term supermoon, and it has come into wide usage recently. It\u2019s an example of modern folklore, largely accepted and spread by a now-global community, via word of mouth and the internet.<\/p>\n

In astronomy and other sciences, a related term \u2013 perigean tides<\/em> \u2013 refers to the higher tides that can occur when a new or full moon and the month\u2019s perigee coincide, as they frequently do. Simply put, an extra-close new or full moon causes higher-than-usual perigean tides.<\/p>\n

\"Large
View at EarthSky Community Photos. | Lorraine Boyd of Delmar, New York, captured this image on August 1, 2023. Lorraine wrote: \u201cThe Full Sturgeon Moon, also the first of 2 supermoons in August 2023. The official term for a supermoon is a \u2018perigean full moon\u2019. It was such a beautiful, finally very cool, clear night.\u201d Thank you, Lorraine!<\/figcaption><\/figure>\n

Bottom line: Sure, the moon (and sun) creates the tides. And an extra-close moon can create higher-than-usual tides. But this doesn\u2019t mean that an extra-close new or full moon \u2013 a supermoon \u2013 has an effect on human beings. In fact, the effects of a supermoon are imperceptible, and far smaller than those encountered in other everyday situations, such as being near a mountain or even a large building. Of course, that beautiful bright full supermoon will draw your eyes to the sky.<\/p>\n

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