Answer:
They are Dark, and always on the run. without the sun, would be none!
The distance from the top of your head to the floor standing up straight.
What is filled with air and sometimes a gas, tied to a string and often seen on your birthday?
What travels from coast to coast without ever moving?
It comes only before, it comes only after. Rises only in darkness, but rises only in light. It is always the same, but is yet always different.
If itβs information you seek, come and see me. If itβs pairs of letters you need, I have consecutively three. What am I?