I have a totally crack-job theory that makes absolutely no sense, but it's interesting to think about.
Our universe was created by a team of people, called the Programmers.
The Programmers spent the better part of the beginning of time coding and creating the graphics for the universe. After the alpha and beta testing, universe.exe was done.
They booted up the program and let it run, being what is today.
In other words, we are all coded beings, controlled by a complex AI system in a giant program with awesome graphics. However, there are bugs in the system that are fixed as they are noticed by the Programmers. This is what unexplainable things are. Diseases are viruses that made their way into the program.
I just realized this sounds a lot like the Matrix. lol
Anyway, the end of the universe is the deletion of universe.exe. But the Programmers have backups. So we'll be fine.
If this were all actually happening then I just don't know anymore.
