Well, not everything is infinite, speed can't be infinite, because the speed of light in a vacuum is the limit, and it's not infinite, because we can measure it. Mass can't be infinite, if the universe has a size that's not infinite, as well as energy, but only if that's true. Fields can't have their values go on forever...time has a limit, the end of time is when the universe ends...but only in the Big Crunch Model. Well, objects can have infinite size, only if it has no mass.
See? So many things aren't infinite...I believe in Albert Einstein, and whatever the pioneers of science say.
We know what's at the bottom of the ocean, because there was a submarine that went to the very bottom of the ocean. But it didn't last forever, because of the pressure.
(Is this like Bla's replies?)