Rainbows Are not Half-round, They are full circles

This fact is maybe something that many common people don't know, I was one of them actually.., who believe that the shape of a beautiful colorful rainbow that appears after the rain was a half-round. then I finally knew that the original shape of rainbows are full circles and not like an arrow or half-round as I had seen and believed.

src

by knowing that a beautiful rainbow shape is full circle certainly makes us wonder, if a rainbow is really a full circle, then why do we only see it as a semi-circle or half-round? is half of its shape into the ground or what ?...

well,, To answer the following questions, we'll have a little touch with physics and mathematics...

as we know that Rainbows usually form when the Sun shines (returns) after rain. If the Sun is behind us and the raindrops still remain in the air in front of us, then we may have chance to see that beautiful rainbow. although only in half of its full form.

the main reason why we only see a rainbow in a semicircle or half-round is because the human ability to see light on a flat place is only around 42 °. so the rainbow's form that is visible to our eyes is included in the 42 ° only. that's why we only see the rainbow in a semicircle instead of a full circle.

src

so the actual rainbow shape is a full circle not a semicircle or half-round. but we usually see it in half-round form due to limited human vision.

so could we see the shape of the rainbow in full form or in a full circle ?..
the answer is yes !!, we can do it ..

look at the picture below !!

src

this is a picture of a perfect rainbow shape, really beautiful isn't it?, well but as we can see that this picture is taken from a quite high place, and not a flat place like we see the rainbow as usual.

To be able to see a full circle of the rainbow, we must enlarge our range of vision. that is, by seeing the rainbow from a height place.

The size of a rainbow is also a factor in being able to see a rainbow in its perfect shape. Large rainbows would need a higher place than smaller rainbows...

References :

1. rainbow | National Geographic Society
2. If Rainbows Are Circular, Why Do We Only See Arches?
3. Rainbow - Wikipedia