Question: How can we see a rainbow with no rain?

Answer: There can be instances where we see rainbows when there are no rain showers associated with it, but first we will talk about how rainbows form.

A rainbow is caused by the sunlight in the atmospheric conditions the light enters a water droplet, slowing down and bending as it goes from air to denser water. The light reflects off the inside of the droplet which separates it into its wavelengths or colors; they exit the droplet and make the rainbow.

Some of those with those different wavelengths get bent more than others when the light enters the water droplets. Violet is the shortest wavelength of the visible light spectrum, it bends the most and red is the longest, it bends the least. When light enters the water drop it is separated into all of its different wavelengths there and the light reflects back to you, the observer with the sunlight coming in from behind. And the water droplets will appear to be separated into all the different colors of the rainbow with violent on the bottom, and red here on top.

One of the main ways a rainbow can form without any rain is called virga. The rainbow formed due to rain but the rain evaporated before it hit the ground.

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