Answer:
By Moon or by Sun, I shall be found. Yet I am undone, if there's no light around.
A leathery snake, with a stinging bite. I'll stay coiled up, unless I must fight.
What has a neck and no head, two arms but no hands?
I always follow my brother but you cannot see me, only him. You cannot hear him but you can hear me. What are we?
I fly, yet I have no wings. I cry, yet I have no eyes. Darkness follows me. Lower light I never see.
Iām grown from darkness but shine with a pale light. Very round I am and always a lady's delight.