A glory rainbow, often simply called a glory, is an optical phenomenon that appears as a series of concentric rings of color seen opposite the sun, typically around the shadow of the observer's head.
Key Characteristics of a Glory
Here's a breakdown of what makes a glory unique, using information from the reference:
- Concentric Rings: A glory is composed of one or more rings that are centered on a point opposite the sun.
- Color Pattern: Each ring is distinct, with the outer edge being red and gradually shifting to a bluish hue towards the center.
- Dimming Effect: The rings become dimmer as they extend outward from the center.
- Smaller Diameter: Unlike a traditional rainbow, a glory has a much smaller diameter.
- Cause: Glories are caused by a different physical processes than rainbows.
How a Glory Forms
Glories result from the interaction of light with small water droplets (or sometimes ice crystals) in the atmosphere, such as those found in clouds or fog. The specific mechanisms involve:
- Backscattering: Light is bent or scattered backward by the droplets.
- Diffraction: This is the bending of light around the droplets.
- Interference: The bent light waves interact with each other, creating the rings of varying colors.
Distinguishing a Glory from a Rainbow
It’s crucial to differentiate a glory from a standard rainbow. Here's a table summarizing the main distinctions:
| Feature | Glory | Rainbow |
|---|---|---|
| Appearance | Series of concentric, colored rings | Single arc of colors |
| Diameter | Much smaller | Much larger |
| Cause | Backscattering, diffraction, interference | Refraction and reflection of sunlight |
| Location | Around the observer's shadow | In the opposite direction from the sun |
| Color Order | Red on the outside, blue towards the centre | Red on the outside, violet towards the centre |
Practical Insights
- Observation: Glories are most commonly seen from mountains, airplanes, or other elevated vantage points where a shadow can be cast upon a cloud or fog bank.
- Conditions: They are typically observed when the sun is behind the observer and a suitable cloud or fog layer is present in the opposite direction.
- Photography: Capturing a glory with a camera can be tricky, as the subtle nature of the rings can be difficult to capture.
Glories are fascinating optical phenomena that reveal the complex interactions between light and tiny particles in the atmosphere. They offer a captivating display for those lucky enough to witness them.
