Linked here are two attempts separated by 250 years to understand beauty. One is Edmund Burke's 1757 work, "A Philosophical Enquiry into the Origin of Our Ideas of the Sublime and Beautiful," which I began (and never finished) many years ago.
The other is less expansive but perhaps a bit more accessible. Ken Taylor offers his thoughts on athletic beauty at Philosophy Talk, venturing into aesthetics with a brief essay in advance of the audio cast (also available at iTunes).
He offers this brief descriptive on beauty:
I won’t try to describe aesthetic experience. You all have had aesthetic experiences. But I will say something further about the objective sense of “beauty.” What property does it denote? Actually, I think this is a misleading question. There are several different properties that something can have to make it beautiful in the objective sense. I doubt I can give a whole list, so I won’t try. But some words will suggest what some of these properties are: simplicity (in an appropriate context), harmony (the matching of parts), and fluid motion. That these properties are distinct can be seen as follows: something can be harmonious without being simple (a Bach cantata); something can be simple in the relevant sense without having fluid motion (a simple painting); and something can have fluid motion without either simplicity or harmony (a turbulent rapids). And, again, the reason why these properties all get to be denoted with the same word, “beauty,” is that they all, when recognized, elicit a certain kind of experience.