Answer:
I'm a god. I'm a planet. I measure heat.
Turn us on our backs and open up our stomachs you will be the wisest of men though at start a lummox.
I am seen in the water. If seen in the sky, I am in the rainbow, a jay's feather, and lapis lazuli.
I can be cracked, I can be made. I can be told, I can be played.
Don't do this in the shallow end.
Be sure to shout for its answers are weak, but there is no language it cannot speak.