Art and Science

What are the similarities and differences between Art and Science?
It seems to me that science attempts to understand all aspects of the external world, while art attempts to express the internal world; that of the brain - primarily the feelings and experiences of the individual and/or group.

Of course another's brain, to somebody, is the external world. Films, paintings and poetry can convey to me the internal world of somebody else. But then so can (sometimes) brain scans...

I'm not saying that a brain scan is anything like a poem today. But couldn't a heap of information read like a poem to a scientifically advanced creature? Can't scientific information steadily represent more and more of what Art can, as a form of human expression?