What is outside the universe? Multiverse Theory
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We can imagine the universe in which we live as a soap bubble; we are inside the bubble. Imagining a Multiverse for many years the subject of multiple universes was the exclusive province of science fiction. The concept of a multiverse has also formed an integral part of both popular science fiction such as Star Trek and more serious science fiction too.
1.0 Quantum Fluctuation and Multiverse
Cosmologists suggest that random quantum fluctuations in the expansion during the period of inflation after the Big Bang were responsible for everything we see now. This mechanism produces tiny random fluctuations from point to point in space, which lead to the formation of 182 Cosmological Enigmas an infinite number of individual universes, each with random initial conditions, which then evolve in their own way dependent on those conditions.
This means that all possible universes develop, but ensures that most of them will be close to the most probable universe and presupposes that our Universe is similar to the majority of other universes in the multiverse.
1.1 After Big Bang
After the Big Bang and the brief period of initial inflation, different regions of space with slightly different physical laws were enclosed in separate volumes of space. Or, to put it more accurately, the equations of physics are the same, but the constants that go in them are different. Our Earth has a certain mass and diameter, and that leads to a certain strength of pull of gravity: an escape velocity of 11.1 kilometers per second.
1.2 Physical Laws in Alternate Universe
Suppose we go to a different region of the multiverse; in this region the gravitational constant may be double, or 10 times as large so, instead of an escape velocity of 11.1 kilometers per second, our own Earth might have an escape velocity of 22.2 kilometers per second, or even 111 kilometers per second. Or, to take another example, the strong and weak nuclear forces might be different in another part of the multiverse. This would have some fundamental effects.
If, for example, the weak nuclear force, which controls beta decay were stronger, radioactive elements that decay by converting a neutron into a proton and emitting a positron would decay far more rapidly and would be more radioactive.
1.3 Parallel Universe
In a different part of the multiverse, the strong nuclear force, which binds atomic nuclei together, may be very much stronger than it is in our Universe—the same force, the same physical laws, but simply a different strength. This effect led to the detection of the parallel universe.
These examples show how the same physical laws can give completely different results in different universes of a multiverse just by changing the physical constants that control their strength. In our universe, the set of laws and physical constants that we have oblige stars to be accumulations of hydrogen that are a minimum of 50 to 100 times the mass of Jupiter even to be a dim red dwarf, while a star like the Sun is 1,000 times the mass of Jupiter.
In an alternative universe we might find that an object the size of Jupiter would be a massive superstar or alternatively that something the size of our Sun would be a cold, dark planet according to how strong or weak the strong nuclear force is and how much mass is thus required to initiate fusion reactions.
Similarly, in a universe where the constant of gravitation is much stronger, we might find that our own Universe would be massive enough to be strongly closed and collapse back in on itself. Seemingly trivial changes in the rules can thus lead to universes that are totally different from each other, even if the laws of physics that govern those universes are constant.
2.0 Quantum Inflation and Multiverse Theory
A multiverse will result if the initial inflation of the universe is chaotic and multiple regions of the Big Bang are enclosed in individual bubbles. The laws of physics are fixed as they freeze out during the initial expansion of the Big Bang.
If the inflation is chaotic, many bubbles of space can form, each freezing out at a slightly different moment and with slightly different versions of the laws of physics, manifested as different “universal” constants of physics to the ones in our own Universe.
2.1 Unsolved Questions of Big Bang
Although the Big Bang theory has been extremely successful in explaining the early history of the Universe, there are a number of questions that remain to be 184 Cosmological Enigmas answered. One of the key questions is the presence, or rather the apparent absence, of a particular particle that theories state should have been created in huge quantities in the Big Bang.
Particle physicists have been searching for many years for evidence of a particle known as a magnetic monopole. The existence of this particle was first predicted by Paul Dirac in 1931. In nature we know that any magnet we can make, however tiny, must have both a north and a south pole. Dirac suggested that there must be particles in the universe that are isolated north or south poles.
Theory predicts that untold billions of extremely massive magnetic monopoles should have formed in the Big Bang. The fact that there are no obvious monopoles in our Universe is a problem for Big Bang models and suggests that maybe they are simply elsewhere than in our Universe, or so spread out as to be undetectable
2.2 Flat Space
Another problem is the flatness of space itself. Observations show that the Universe is extremely flat on a large scale, whereas the models suggest that it should be strongly curved. What this means is that instead of having a mass close to or superior to the critical mass that would close the Universe and thus space that would be strongly curved by gravity, the mass of the Universe is far below the critical mass and thus space is unexpectedly and quite unreasonably flat.
2.3 Why believe in such a multiverse?
Supporters turn to what they call “fine-tuning.”They argue that our Universe is inherently improbable. For example, only 1 in 1,000 universes should have a CMB as smooth as in our Universe. However, there What Is There Outside the Universe? 185 are many more examples in physics of how, were the laws of physics written just slightly differently, our Universe would be impossible. Opponents of the multiverse concept state that this is a misuse of the anthropic principle.
3.0 Social Thoughts
In other words, opponents suggest we are obtaining false conclusions from skewed data that make a particular answer inevitable. The argument over this point is heated and unlikely to arrive at a conclusion in the near future.
The battleground for this multiverse theory is thus whether we are skewing the data by picking just the peculiarities that make us possible to justify the fact that we exist.
It supposes that the random nature of quantum physics allows exactly the same physical laws to exist in all possible universes but that, at every moment in time when there is a branching of events, different universes peel off allowing all possible histories to occur.
For example, you decide suddenly that you need something at the shop and leave just at the moment that the man or woman of your dreams is about to pass your front door. At every particular branch point, all possible outcomes will happen in one universe or another. The basis for this idea is that quantum physics does not allow absolute certainty. Everything is described as a wave function, which does not allow its position to be fixed absolutely.
3.1 Uncertainty and Multiverse
The most famous application of this is the Heisenberg uncertainty principle, which states that if you establish the position of a particle—say, an electron—with infinite precision, you will know its velocity with infinite uncertainty, for the product of the two errors cannot be smaller than a certain quantity.
Physics is identical in every universe of the multiverse, so there are no problems with alternative universes in which the Sun is unstable, or we cannot form the elements required for life and spread them through space with supernova explosions. The only difference between the universes is the way that at every possible crossroads of history, however trivial, every possible course gets taken by history, each in its own universe. The scientists who support multiverse propose that our Universe is governed by a particular mathematical structure.
3.2 Conclusion
That being so, there is no reason why we should not envisage other, different mathematical structures to describe the universe. That being so, if a particular mathematical structure exists that describes a possible universe, why should only the structure that leads to our universe be the only one that exists; why not all the other structures too? In other words, if a solution to a universe exists mathematically, that solution must logically and automatically exist physically, too.