Is it possible to create an exact replica of the film "Gravity" using Blender Cycles?

And 4 super-computers.

They say it was entirely CG except for the 2 character’s faces.

After learning that, I am impressed to create a scifi thriller film set on the jungle using only a 3d modeling and animation software.

The render engine used in the film ‘Gravity’ uses similar path tracing tech currently seen in Cycles.

Here’s the difference though, that engine (Arnold), is a lot more mature and a lot more optimized (both in the way of convergence rate and raw speed). Cycles would probably not be able to do it yet because of this, but it’s not to say it could if it was developed for the same period of time as Arnold was.

As for your movie idea, don’t even try to start on such a project if you’re not an expert at 3D and don’t have a paid team of hundreds of people to work with you, and even then, you would need to have a large renderfarm to pathtrace such scene because a lot of movie scenes these days you would struggle to replicate on consumer hardware.