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The Sun’s Halo: An Enchanting Optical Phenomenon Visible Across Vietnam

On the morning of June 16, residents across the eastern provinces of Vietnam were treated to a stunning phenomenon as the sun appeared surrounded by a radiant halo. This captivating display, lasting for several hours, captivated onlookers and sparked curiosity.

Administrator

28 July, 2024

The Sun halo is a natural optical phenomenon that occurs when light is refracted at a 22-degree angle, often visible when a thin layer of clouds is present in the sky, causing sunlight to refract and create a halo effect.

The Sun halo as captured by us

1 What is a Sun halo or Sun ring?

The Chairman of the Vietnam Astronomy Association – VACA stated: “This is a 22-degree halo phenomenon. This optical phenomenon occurs in the Earth’s atmosphere near the Sun or Moon disk when the weather is very dry with little moisture, and the upper atmosphere has a low density of ice crystals (water ice). Light from the Sun or Moon, when entering the atmosphere and passing through these hexagonal crystals, is refracted, creating an effect similar to that of a diverging lens. This forms a white ring with a radius of about 22 degrees (a diameter of 44 degrees) around the luminous disk. This phenomenon is commonly observed with the Moon and less frequently with the Sun.”

Regarding the Moon’s halo, because it occurs when the air is dry and less humid, the Vietnamese have a saying, “When the Moon has a halo, it foretells dry weather, and when it has a crown, it foretells rain.” In this context, the halo refers to the 22-degree halo of the Moon. Although less common, a Sun halo is not a rare or mysterious phenomenon and is not a sign or omen of any event. Nature photographers often capture fascinating images when this phenomenon occurs around the Sun’s disk.

According to scientists, this phenomenon can appear in various colors, depending on factors such as time, water vapor, and dust in the atmosphere. As a result, people in different locations may observe the Sun halo in different colors.

The Sun halo as captured by us

2 Let’s take a look at some images of the Sun halo from today.

Sun halo

Previously, a Sun halo was also observed in several locations, including Hoi An, Hue, and Danang, in late April.

Sun halo

This is considered an interesting optical phenomenon, and according to scientists, it indicates the likelihood of rain as cloud accumulation, combined with hot weather, can lead to increased evaporation and subsequent rainfall in the area.

Frequently asked questions

A sun halo is an optical phenomenon that occurs when light passes through ice crystals in the atmosphere, creating a halo around the Sun.

Sun halos are formed when the sunlight is refracted by ice crystals present in thin, high-altitude cirrus clouds. These clouds are composed of tiny, uniformly shaped ice crystals that act as prisms, bending the light at a 22-degree angle and producing the circular halo effect.

The halo is usually white in color, but sometimes it can also appear to have a reddish or rainbow-like hue. This variation in color depends on the size and orientation of the ice crystals, as well as the angle of the Sun in the sky.

Sun halos are not rare phenomena and can be observed several times a year in various parts of the world, including Vietnam. However, their appearance is fleeting and they usually last for only a few minutes to an hour or two, depending on the atmospheric conditions.

In many cultures, sun halos are considered auspicious signs, bringing good luck and fortune. In the past, they were often seen as omens or messages from the gods. For example, in Norse mythology, a sun halo was believed to be the goddess Freya riding in her chariot, signaling the arrival of fair weather.