So you may know of the "
many-worlds hypothesis," a
concept in
quantum physics which in essence says that every time some "
decision making"
event happens in the
Universe -- like an
electron having to "decide" which way to jump next in its random path around the
atomic nucleus -- then the Universe splits in two, one for each possible
outcome. The result of this splitting is called
many worlds, which is one
hell of an
understatement. Consider that the typical electron makes several million such jumps every second, and multiply that by the number of electrons in this
galaxy alone, and you're
immediately speaking of an uncountable number of spinoffs -- as in
trillions to the trillionth power -- in the first few
seconds out of the gate. And remember that every single one of those will immediately start splitting off into more Universes (not "new" Universes, mind you, because every single one is the same Universe, just with a different spin), and that if the measures of modern science are correct, this has been going on in relation to the Universe we
know for about
thirteen and a half billion years (and, face facts, even just
a billion years is a longer time than you can comprehend).
I will now logically demonstrate (I think) that this theory is quite probably untrue: if there are trillions to the trillionth trillionth trillionth power
alternate universes (and the number increasing by that much, exponentially, every minute) then there should be some where humankind sprouted earlier and developed technology far in advance of what we now have. And remember, if there is even one such Universe, than in another second there will be trillions of trillions of splitouts from it. Now, if there are in fact such advanced stages of technological achievement, there must be some in which man (or some superadvanced kind of future-man) has conquered the distance between the alternative Universes themselves, and can travel from one to another at a whim. And since the number of such Universes almost instantly climbs near infinity, there
must be some Universe from which (as a matter of alternative history) future humans have visited
our Universe. Now, I realize that there are a number of objections that you might raise. First, you could justly argue that all of these alternate Universes exist, but there is no way for events in one to affect another. This proposes a limitation on the power of science to act, and more importantly suggests that it is impossible for us to
ever know if indeed there are any alternate Universes out there, because as the
Heisenberg uncertainty principle relates, there is no way to observe something without altering it in some way. Or you may say that these alternate Universe types have simply not found our
particular Universe, or have not chosen to visit it -- except that as soon as there's a choice to be made, infinite alternates would split off from which the other choice
was made, i.e. to turn the alternate Universe visiting device in
our direction, and thence to visit our particular corner of it.
You may also object, "surely
visitors from alternative Universes must obey some code of conduct to prevent mucking about in the history of their neighbors," meaning in short that such visitors wouldn't make themselves known to be visitors. This is, after all, a satisfactory answer to the question,
Where are all the time travelers? And where
time travel exists in but a single Universe it might fall within realistic regulation in that Universe.
But with nearly infinite multiple Universes, there
must be at least one variation from that model (and therefore an uncountable number of variations of that model) in which the visitors have no such code (or it is unenforceable, or at any rate unenforced). So, rules aside, we should be absolutely flooded with visitors from alternative universes in garish
Uranian t-shirts, loudly proclaiming themselves as such and lording about all sorts of
impossible technology.
And here is an even more chilling consideration. Some alternative-Universe-crossers are bound to be warlike, and in fact alternative-Universe-
conquerers, and some will have empires of equally uncountable numbers of Universes under thrall. Now, I mentioned before that in some Universe, the technology for alternative-Universe jumping must be known, and so it is that in another Universe, the technology must exist by which alternative Universes can be destroyed!! And, if there are bound to be warrior-Universes out there, there must be at least one Universe willing to defend itself from potential incursion by
preemptively destroying all the others. So by all rights, our Universe should have been eliminated billions of years ago!! And yet, here we are, and so apparently we are alone not only in the
Universe, but among all of them that ever could be....