aesthetically, why choose a wider ratio (2.35) over a less wide (1.78) ratio?
 

example why would star wars or lord of the rings use 2.35 over 16:9 ratio? and why do works like back to the future use a more square ratio as opposed to others? why do you think they choose it that way? artistically? economically? practicality? i'm just wondering out loud.

Yes to all of your questions.

16:9 is a new format. Specifically designed for TV not film. Film formats have varied greatly over the years, as has the method of achieving them. Ranging from anamorphic lenses, to running the film "sideways" to get larger negatives. There is a widescreen webpage that explains the development of the various formats.

The wider screen image is designed to more closely mimic the human field of vision.

I think the webpage is www.widescreenmuseum.com

Lord knows why some of the artistic choices are made in movies... but I suspect it may have more to do with tradition than artistic values or econonic, and certainly not practicality. In the early 1950's movie attendance dropped off as the TV became popular. In an effort to get people back into the theatres the idea of big, wide screens caught on and were used for some of the great epic films of that era. This led to a certain style of composition and story treatment that became popular and that we now associate with a big Hollywood epic - Like Star Wars or Lord of the Rings.

If you haven't visited before, check out The American Widescreen Museum website, which is really incredible. I think it will give you some perspective on this whole topic.

Now what I find really funny, and often annoying, is the number of TV commercials that are using a widescreen mask these days. Now I'm not talking about 16:9 because I understand they may be trying to "future proof" their ads. I'm talking about 2.35:1. Yes, there are some well made ads that I can admire, but the ones I'm talking about are often for really mundane things. The idea of being "cinematic" when you're advertising file servers or insurance is pretty laughable.

Prior to the wide spread adoption of TV, most movies were shot in 4:3 ratio. Thats why TV was designed in 4:3, to be able to broadcast the already large number of existing films.

When TV started taking a lot of business away from the theaters, Hollywood responded with wide screenformats (some even more than 2.35:1). 3d/stereoscopic formats were tried too. note..the original format for Hitchcocks 'The Birds' was supposed to be presented in 3d.

What ever 'artistic' motive was claimed, it had more to do with trying to keep people coming back to the theater. It just so happened, the wide screen formats turned out to be for the most part a superior format. Anamorphic lenses were developed so existing 4:3 cameras could be used (saving money).

The original 4:3 format for film was designed by Thomas Edison. And 4:3 format on a large screen still looks pretty good.