When the sun comes out after a shower, the rainbow won't surprise you-after all, these are classic rainbow conditions. What happens is that the light wave from the sun first bends and changes its speed (called refraction) when it enters the raindrop; Then, they bounce (reflect) from opposite sides of the water droplets and leave the direction in which they entered, and refract again as the surrounding environment changes from water to air. Because the angles of color refraction are different, stripes of different levels are formed.

Knowing this, it seems that a rainbow without rain is impossible. So how did this happen?

As Rachael Witter, a meteorologist in new york, told 96. 1 The Eagle, the rainbow you see may actually be formed by rain-but the rain evaporates before it falls to the ground. This type of precipitation is called virga, and sometimes you can see fuzzy patches extending under the clouds.

However, rain is not the only water known to produce colored stripes or arcs in the sky. When light is refracted and reflected on ice crystals in the atmosphere, many phenomena will occur. Some of these so-called halos are not rainbow-colored-just like light beams, they are called light beams and usually extend above the rising sun. But others do show colors, and which subcategory they belong to mainly depends on the angle and the position of the sun. For example, halo 22 is a halo with a radius of 22 degrees around the sun (they can also be formed around the moon). Sometimes, a rainbow dot called parhelia-also known as "magic day" or "simulated sun"-will appear along this halo.

The circular horizontal arc or "fire rainbow" is a kind of colorful solar halo parallel to the horizon, which only appears when the sun is higher than 58 degrees. Its counterpart is the zenith arc, which appears when the sun is below 32 degrees.

Although these rainbows are not technically rainbows, they have the same refraction and water as them. They are equally excellent.