Ring of Fire

If you’ve followed this project for a while, you know we’re big fans of eclipses.

Lunarsolarpartialfull: we love them all.

The United States is currently in the midst of a glittering age of eclipses. In 2017, many across the country glimpsed the “Great American Eclipse,” a full solar eclipse. Under seven years later – the blink of an eye in astrological terms – on 8 April 2024, much of the USA will get another shot at totality, as the moon will completely obscure the sun.

Plan ahead for this event. Based on eyewitness accounts of total solar eclipses, they can be monumental, life-altering experiences. Here’s the path of totality for April 2024:

The path of totality for 8 April 2024 - graphic by Great American Eclipse, LLC

In addition to these two spectacular shows, the United States will also be blessed with another major astronomical happening.

On 14 October 2023, a sliver of the continent will experience an annular eclipse. These types are also known as “rings of fire.”

It’s easy to see why an annular eclipse garners this nickname:

An annular eclipse in India in 2019 - photo by BrijeshPookkottur

As we’ve learned before, eclipses occur during syzygies, an alignment of three celestial bodies. For human eyes, these three bodies are the Sun, the Moon, and the Earth. When the Earth happens perfectly to intersect the Sun and Moon, we get a lunar eclipse, in which the planet’s shadow is cast upon the satellite. When the Moon happens to intercede between the Sun and Earth, we see a solar eclipse. In a partial eclipse, just a bit of the Sun is concealed. If things line up just so, the Moon’s disk happens to completely shroud the Sun, temporarily blocking out light from our star.

The anatomy of a lunar eclipse - graphic by In-the-Sky
Solar eclipse diagram - graphic by Ana Pelisson
A partial solar eclipse in Brazil in 2006 - photo by Helder da Rocha
Total solar eclipse in Bangladesh in 2009 - photo by Lutfar Rahman Nirjhar

The images of a partial and total solar eclipse make a lot of intuitive sense. During totality, the Moon lines up perfectly, blocking all but the Sun’s corona. In a partial, things aren’t quite aligned correctly and our satellite only covers a bit of the star.

But what’s going on during an annular eclipse?

An annulus is a mathematical term for the space between two concentric circles. The word is Latin for “little ring.” Think of a metal washer and you’ve got an annulus.

An annulus - graphic by Dmcq

The ring of fire is, in a way, a mix between a total and partial eclipse. During an annular event, the Sun’s light is not completely obfuscated, meaning it shares illumination aspects with a partial eclipse. However, this “partial” eclipse is a special one. In slightly different celestial circumstances, an annular eclipse would be a total, as the alignment of the three bodies is dead-on.

The orbit of the Moon around the Earth is not circular but elliptical. As such, at some points, the Moon is closer to us and, at other points, it’s farther away. The closest point is called the perigee and the farthest is the apogee. These apsides produce supermoons and micromoons, as Luna’s apparent size changes in our skies, depending on how far away it is.

The elliptical orbit is also responsible for annular eclipses.

A ring of fire eclipse transpires when the Moon is close to its apogee, relative to Earth. Things align well enough to create a total eclipse, but the apparent size of the Moon is too small to completely block the Sun. The smaller lunar disk creates an annulus with the larger solar disk, leaving a conflagration around the rim.

Though witnesses of total solar eclipses testify that the awe of day becoming night for several minutes is a unique experience that dwarfs other types of eclipses, the imagery of an annular eclipse seems to stand on its own pedestal, as well. The contrast of blackness and fire is sublime.

In October 2023, Oregon, California, Utah, Arizona, New Mexico, and Texas will be treated to a ring of fire. If you live in these areas, grab your eclipse glasses and watch for this incredible annulus in the sky. If you miss it, you won’t have another chance to see the striking ring in the contiguous United States until February 2046.

If you can’t see it in person, you can tune in to the official NASA livestream!

The path of the annular solar eclipse over North America - graphic by Great American Eclipse, LLC

Further Reading and Exploration

Eclipses – NASA

2023 Annular Eclipse: Where & When – NASA

2024 Total Eclipse: Where & When – NASA

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