Adam Frank for McGraw-Hill

It's not just chaos. It's not just a mess. It's not just a random scattering of stuff strewn across the cosmos. For some reason, a strange reason which scientists are still grappling with, the Universe has order. The Universe has structure. There are organizing principles that create shape out of shapelessness, form from formlessness and stretch from the very small to the impossibly large. The Universe's inherent tendency to create forms is all around you, just look at your hand or the Milky Way on a dark night. Where does all this structure spring from?

It's important to realize that it did not have to be this way. Astrophysicists now understand that the Big Bang which created our Universe may be just one of many Bangs. Many cosmologists, astronomers who study the birth and evolution of the Universe as a whole, believe that instead of a Universe it would be better to talk of a Multi-verse. There may have been, may still be, thousands or millions of Universe's created. That may seem like a mind-numbing idea but it gets even more insane. The Laws of Physics can change. Each Universe will have different physical laws from the ones that emerged in our cosmic home. Different physical laws mean different tendencies to organize matter and energy into structure and form.

In our Universe there exist four basic forces: Gravity, Electromagnetism, and the so-called Strong and Weak Nuclear Forces. Everything we see, everything we touch and experience is the direct result of these four ways the Universe has to push and pull. You have a lot of experience with the first two forces, Gravity and Electromagnetism. They keep your feet glued to the planet and power your favorite electronic gizmos. The Nuclear forces, which hold the cores of atoms together, are less familiar since they only show up on sizes less than a billionth the width of a human hair. In spite of their invisibility the nuclear forces are not to be forgotten. They control the rate at which stars produce their warm, life-giving glow and the form of the periodic table of elements. The nuclear forces are what make elements possible in the first place.

The existence of the four forces are a consequence of (poorly understood) physics that occurred right after the Big Bang. At some time less than a billion, billion, billion-th of a second after creation there was just one unified force controlling the primordial soup of the Big Bang. Then the forces we know, the ones that give this Universe atoms and molecules and people, 'froze out' of the single original force. The details of how this happened are crucial. The existence of stable atoms and molecules (key for life) depends on the strength of electromagnetism. The existence of long lived stars (long enough to allow life-bearing planets to form) depends on the form of gravity and the nuclear forces. If these forces were different by even a minute amount then none of the structures we are familiar with could have formed.

If cosmologists are right and there are many Universes, some of those are bound to have different forces than others. In some Universes our four forces might not have formed at all. In others, Gravity may exist but it's much stronger collapsing all cosmic gas into a single giant lump rather than the manifold stars and galaxies we see in our sky. In other Universes, the Nuclear forces might be too weak for fusion to occur never allowing the light of stars, and the life they may engender, to emerge. There are almost as many possibilities as you want to imagine and most of them would be pretty dull. It appears there are many ways to create a dead, formless Universe and that makes the one we are in now all the more remarkable.