The ‘ring of fire’ is an annular (ring) solar eclipse. It occurs because the moon’s orbit of the Earth is elliptical, so its apparent size in our sky waxes and wanes throughout the month. Normally, this goes completely unnoticed. Even during a ‘supermoon’, when the moon is at its largest apparent size (something called perigee) it's a difficult thing to see. However, the apparent size of the moon becomes most noticeable during a solar eclipse. A total solar eclipse occurs when a perigee moon crosses the sun, while an annular solar eclipse is when an apogee moon—the furthest it can be from Earth—crosses only the central part of the sun. On October 14, 2023, up to 91% of the center of the sun’s disc will be covered by the moon to cause a ‘ring of fire’—in effect a pretty kind of partial solar eclipse.