Yeah, I just read that on Wiki. I'm kind of on the fence with this. I can see why people don't think Gravity is sci-fi because there are no imaginary elements (like those mentioned) at play. However, I can also see why some would call it sci-fi, going back to what my last post said. It's not on accident that most articles and movie reviewers are calling it a sci-fi. Although it may not be the techinical definiton of what a sci-fi constitutes, the general public has seemed to consider sci-fi anything that takes place in space and shows scientific elements. I'm not saying they are right, but just stating what the public views as sci-fi, which is why that is Gravity is being called it.
I'm really either way, and I don't really care if it's sci-fi or not.