The Oscillating Universe

If this scenario is correct, what does the awesome process of giant black holes consuming entire galaxies mean for the future of the universe and for humans and any other intelligent beings that may exist in the vast reaches of space? First, the process will take a long time, perhaps thirty, fifty, or even hundreds of billions of years or more. So most galaxies and intelligent civilizations are not in any immediate danger. Eventually, though, Sagittarius A* will likely swallow up all the normal matter surrounding it, including the Sun and its planets. After its humongous meal, this bloated black hole may then float through space until it encounters other giant holes that have already devoured their own former galaxies. And relentless gravity will inevitably cause these phenomenally massive objects to move ever closer to one another and merge in an embrace of self-annihilation.

Carrying this possible sequence of future events even further, after unknown numbers of eons all of the galactic black holes together containing all the former matter in the universe might merge into one huge monster of a black hole. The fate of this bizarre cosmic creature can only be guessed. But some astronomers postulate that this ultimate end of the present universe will somehow give rise to the birth of a new one. Perhaps there will be a new Big Bang, in which immense quantities of matter rush outward from a central point and slowly coalesce into stars, galaxies, planets, and so forth. Logically, in this new universe new black holes will form. And in time, these will slowly but steadily begin a new cycle of growth and merger. Astronomers call this theoretical situation in which all matter repeatedly contracts and rebounds the “oscillating universe.”

It is only natural to wonder about what will happen to humanity in the ultimate cosmic crunch, when all matter in the present universe is incorporated into one or more titanic black holes. However, it is highly unlikely that human beings, at least in their present form, will exist billions of years from now. If our species is not long since extinct by that time, it will have undergone profound physical and mental changes, enough to be totally unrecognizable to people alive today. Still, it is at least possible that our descendants, in whatever form, will be around to witness the climactic ending of what will become essentially an all-black-hole universe. Could they survive the final crunch? John Taylor gives this thought-provoking answer:

The fate of the physical universe is catastrophic. . . . It is either to be crushed into its fundamental constituents, as far as possible, to make a universal black hole, or it is to be slowly absorbed by local black holes, again to be crushed out of existence as we know it. . . . At such an end, [we would surely face physical death, so] we could only appeal to our souls, if they exist, to preserve us. . . . It could only be if the universe bounces back again after its collapse that these separated souls have any chance of returning. . . . There is very little evidence of such a bounce being able to occur, but if it does, only then can one expect any form of immortality.

Searching for a Definite Beginning

In this excerpt from his book Black Holes, scientist John Taylor points out that the concept that the present universe developed from a black hole containing the remnants of a prior universe is difficult for humans to comprehend because it does not define the beginning of the process.

The hardest question of all to answer is where did our universe come from? If we reply that it came from somewhere else, brought to its present state by the laws of physics, we need only add that somewhere else, filled with whatever was in it before it formed us and our material surroundings, to our present world. We then ask again, where did that new totality come from? Any definite answer to our first question is the wrong one, since it would lead us to an infinite chain of similar questions. . . . But we could try to find from what our world, as we know it today, arose. We might do so by conjecturing that our present universe sprang into being from the final stage of collapse in a spinning black hole in a different universe, bubbling out of the black hole’s center. . . . That might or might not fit with experimental facts if we looked for them carefully enough, but it would still beg the question, since we would then have to explain where the previous universe came from.