The universe is a little early, so it haven`t happened yet probably, but when a black hole get`s heavy enough, it collapses, and forms a new sun, all the matter is gathers, all the used energy, makes it heavier, and heavier, all matter is energy, and when the sun burns, it makes old energy, old energy have a little mass to it, that`s also how planets can have more mass, than it seems possible without saying it`s from black matter, yes, I don`t really believe in dark energy, or black matter, but you have something called old energy which forms when sun burns, that old energy gathers around planets because of gravity, so there`s the explaination of how it can stay together, so the universe, won`t just end in darkness, there`s always black holes that`ll form a new sun again, but a downside to the theory of traveling through a wormhole though, since black holes just gathers mass until it collapses, there`s no tunnelling, and also, since the first sun/energy, came to be from nothing, there`s perhaps, a chance, it`ll happen again, and since the universe is infinite in all directions also, there have to be infininte amount of black matter also to cover it all, the theory is that it just stretches, and stretches, until the universe collapses, but I don`t think that`s true, what`s your take on it?