Recently, in fact, only a week or two ago, it was announced that scientists had finally proven that the universe is, in fact, expanding.
There was always very influencial speculation that this was so, however, some in the scientific community attributed the apparent expansion only to the rotation of the universe. In short, some believed that the universe was stationary and that rotation was what caused the "red-shift' readings to indicate that it was expanding.
We now have irrefutable confirmation of this, so now, we have another, very important question to ask.
Is it expanding past it's escape velocity? Is the expansion of our universe fast enough to escape gravity's pull? If this is so, then we would grow further and further apart from the rest of the universe forever, as opposed to gravity returning us all to a "singularity" (uuh I hate that singularity) much like a thrown tennis ball returns to the ground.
The problem is, we can never know this In order to determine our universes escape velocity, we need to know how much matter there is in it. Again, the "dark matter/dark energy" conundrum returns here. Only about 70% of the universes matter has been accounted for as of yet, so we cannot approximate our escape velocity.
What are your thoughts? Will we keep expanding forever, or will the gravity of all the matter in the universe eventually overcome expansion, bringing us all closer together until we become a singularity, and the Big Bang once again repeats itself?