Science of Rainbow [all of them are complete circles]

I had the privilege and luck to observe a rainbow form in front of my eyes while traveling in Guadeloupe. The science behind the phenomenon of Rainbow might be the oldest but I was blown away to discover that ALL Rainbows are actually circular, even though we only see arches from the ground. You would have to be high enough to watch the circular rainbow from a birds eye view or high enough above ground.

Here is the science behind the circular nature of Rainbows explained below -