I find it interesting that Jesus provides signs of the end of days as "the stars will be falling from the sky, and the powers in the heavens will be shaken." To me, this sounds a lot like a description of what the collapse of our universe might look like. Jesus seems to be truly talking about the end of time--an event that is both billions of years away and, from our own perspective, as soon as the end of our lifetimes.
Like many imaginative young people, I once pictured myself as living in a time that would see the end of existence. Considering the continual threat of nuclear annihilation where I spent my formative years, it is no surprise that I focused a great deal of my attention on post-apocalyptic stories. Even with the "end of days" seemingly around the corner, I was still certain that life would somehow continue on. I believed this despite the multiple "christian" movies I saw at various bible camps that depicted the end of days.
God has already promised us, through Noah, that He will not wipe out humanity. His death and resurrection shook the universe nearly two millennia ago, and we live now in an era where our salvation has already been purchased. For us, the day of our Lord's coming is the day of our death in this world. The universe still has quite a bit of time remaining in it even if we won't experience it in this form of existence.