Why are there two rainbows in the sky?

Experts gave an authoritative explanation for the phenomenon of "double rainbow": "double rainbow" is what everyone calls neon. The brighter one is the rainbow, also called the main rainbow.

On June 12, the appearance of the double rainbow was mainly due to the rain in the east cloud at night, and there were more raindrops on the cloud. In the west, after being washed by heavy rain, the sun has reappeared, and the sunlight is refracted by raindrops to form a rainbow. The second rainbow we are talking about is formed after secondary refraction, so its color is darker, called neon, also called secondary rainbow. Recently, rainbows have frequently appeared in Taiyuan, mainly because the cold air in the northeast meets the warm and humid airflow in the southwest and the southwest monsoon in North China, resulting in strong convective weather such as thunderstorms and hail. This meeting usually lasts about 10 days, which means that in the next few days, Taiyuan citizens may see the rainbow again.

Double rainbow is a special phenomenon formed after two reflections in water droplets. A concentric rainbow with a slightly larger diameter and reversed color appears on the periphery of the original rainbow. The inside rainbow is called the main rainbow, the outside is red, the inside is blue, and the color is bright. The outer rainbow is called a sub-rainbow, the outer side is blue, the inner side is red, the color is dark, and it looks like a hair band. It is verified by experiments that the main rainbow is caused by reflection at the water point, while the auxiliary rainbow is formed by two reflections. This is one of the wonders of nature. The corner is the brightest and the middle is the darkest.

Many times, two rainbows will appear at the same time, and a concentric but darker secondary rainbow (also called neon) will appear outside the ordinary rainbow. The secondary rainbow is formed by two reflections of sunlight in water droplets. When sunlight passes through water droplets, it will be refracted, reflected and then refracted again. Our common rainbow (main rainbow) is formed by the reflection of light in water droplets. If light is reflected twice in a water drop, a second rainbow (neon) will be produced. The color arrangement of neon is opposite to that of the main rainbow. Because every reflection will lose some light energy, the brightness of neon lights is also very weak. The strongest reflection angle of the two reflections occurs at 50 to 53, so the position of the secondary rainbow is outside the main rainbow. Because there are two reflections, the color sequence of the auxiliary rainbow is opposite to that of the main rainbow, with the outer side being blue and the inner side being red. In fact, the auxiliary rainbow must follow the main rainbow, but sometimes it is invisible to the naked eye because of the low light intensity. Double rainbow over Scotland 1307, it was suggested in Europe that the rainbow was caused by the refraction and reflection of the sun light by water droplets. Descartes found in 1637 that the size of water droplets does not affect the refraction of light.