Because sometimes the colour of sky is blue.

In my language (Thai), we call the sky "Far" in the high tone. We call the light blue colour in the same word. I reckon that my ancestor chose to set the same word in these two things because the sky's colour is similar to the blue colour.

The sky occupies all over the world. I believe that if I look at the sky in one place, somebody should see the sky along with me from where they are belonged to. We can look at the same thing together although we don't even know each other.

“In the sky, there is no distinction of east and west;
people create distinctions out of their own minds
and then believe them to be true.”

~~ Buddha ~~

(Hindu Prince Gautama Siddharta, the founder of Buddhism, 563-483 B.C.)

The quote

[Above photo was taken by SE K750i during my way back home, struck in Bangkok's traffic jam]