My home is the air, the earth, and the sea,
Between highs and lows you are sure to find me.
I am boisterous and loud, as bright as the sun,
But those who can see me or hear me are none.
I am born with a goal, I live in a shell,
I accompany those who greet and farewell.
I have numerous forms, interactions that last,
Like the tooth of a saw or the shock of a blast.
As fast as the wind, I fly through the dark,
None can outrun me, not falcon nor shark.
My essence is motion, my voice is a trill.
Occasionally I will attempt to stand still.
I live everywhere, both far and near,
But when you try to find me, I disappear.
This riddle is from SBHacks 2021!