Triumphant Glow: Ring Around the Moon’s Triumph

Look up at the night sky and you may occasionally see a luminous ring or circle of light surrounding the moon. This optical phenomenon is known as a moon ring or lunar halo. What causes these ghostly circles around the moon? Read on to learn what makes a ring around the moon and the science behind it, scientific explanation, ring colors, forms, halo names features myths and legends, and answer FAQS.

What is a Ring Around the Moon?


A ring or circle around the moon is caused by the refraction, reflection, and dispersion of moonlight through ice crystals suspended high up in the atmosphere. These atmospheric ice crystal prisms bend and spread the moon’s light into a glowing halo that can appear around the moon.

Moon rings usually form when thin, wispy cirrus clouds made of ice crystals move across the night sky. The ice acts as a natural prism, creating a halo effect around the moon. The rings can appear in white or tinted colors.

Ring Around the Moon: The Scientific Explanation

The light from the moon entering an ice crystal is refracted at a minimum angle of 22° as it passes through the 60° angled faces of the hexagonal crystal structure. This refracted light reflects and disperses inside the ice prism, exiting at 22° and 46° angles, creating a 44° radius halo around the moon.

The size of the ice crystals and how uniformly aligned they are determines the brightness and clarity of the ring. Perfect alignment creates the most vivid moon rings.

Ring Around the Moon Colors

While most moon rings look whitish or pale yellow, occasionally more dramatic colored rings can occur:

  • Red – Caused by high clouds of ice crystals
  • Blue – Very rare; requires very specific crystal alignment
  • Rainbow colors – If the spectrum dispersed like a prism

Colors depend on the composition, orientation, and height of the ice crystals. Cooler crystals tend to separate light more distinctly.

Ring Around the Moon Forms

The key conditions needed for a moon ring are:

  • Cirrus clouds – Thin, wispy, and high in the atmosphere
  • Ice crystals – Hexagonal prisms that refract light
  • Clear sky – Allows bright moonlight to pass through
  • Moon not overhead – Moon lower on the horizon

These factors scatter moonlight into a ring or halo. Rings are more vivid when the moon is lower rather than directly overhead.

Ring Around the Moon: Other Halo Names

Moon rings have various folklore names depending on the culture, including:

  • Winter halo – Seasonal reference
  • Frost halo – Referencing icy clouds
  • Moon dog – Two bright patches of light on either side
  • Full circle halo – Complete ring around the moon
  • 22-degree halo – Scientific name based on angles

But they all describe the same optical effect.

Ring Around the Moon: Distinguishing Features

  • Size – About 44° radius around the moon
  • Can appear white or rainbow colored
  • Most vivid with thin cirrus clouds
  • Unique optical effect of ice crystals
  • More pronounced closer to the horizon
  • Transient – They come and go

Moon rings are most noticeable when bright and briskly moving.

Myths and Legends

Various cultural myths and folklore attribute symbolic meaning to moon rings:

  • Predicting weather – Some say it forecasts storms
  • Signifying difficult times ahead
  • Witches or werewolves gathering
  • God or spirits manifesting
  • Omen of challenging seasons
  • Magical portal opening

While evocative, these legends are not scientifically proven. But the mystique contributes to their magical allure.

In Summary:

Rings or circles around the moon are caused by moonlight refracting and dispersing through high-altitude icy clouds. The hexagonal structure of atmospheric ice crystals creates a 22° minimum angle of deflection, resulting in a lunar halo approximately 44° in radius. When conditions like cirrus clouds and bright moonlight align, these luminous moon rings can appear white or rainbow-colored. Though the optical phenomenon has inspired mystical folklore, the science behind moon rings is the unique interaction of light through ice.

Ring Around the Moon FAQS:

How common are moon rings?
Answer: They occur randomly whenever the right conditions exist, so a few times per month generally. More common in colder climates.

Will a moon ring predict rain?
Answer: No scientific evidence supports moon rings forecasting rain or storms. But high icy cirrus clouds often do precede weather fronts.

What is a moon dog? Bright spots of light on either side of the moon, part of the 22° ring, are called moondogs. They form from more uniformly aligned ice crystals.

Are moon rings ever perfectly circular?
Answer: No, the halo is always slightly elliptical due to the moon’s inclination vs. horizon. But they may appear circular to the naked eye.

What causes the colors?
Answer: Greater separation of light spectra through the ice crystals causes rainbow hues in some moon rings. The composition of ice can also affect color.

In conclusion, moon rings have a scientific explanation but their ethereal beauty still inspires awe and mythology. These luminous halos form when moonlight interacts with icy clouds high in the atmosphere, creating a fascinating optical display in the night sky.