After the Primeval Fireball: An Artistic Concept of the Early Universe. Adolf Schaller / NASA hide caption
Adolf Schaller / NASA
Adolf Schaller / NASA
This is the first in a series of contributions on how modern science deals with the ancient question of origin. For as long as there have been records, different cultures have been concerned with the question of the origin of all things. Where did it all come from? Throughout history, creation myths have attempted to treat this subject from a supernatural perspective. In most (but not all!) Cases a god or goddess or ensemble of gods create the world and its inhabitants. For us in the West the best-known creation story is that of Genesis 1 and 2. Here an almighty God creates everything that is ex nihilo: creation out of nothing. God, an absolute power that transcends the boundaries of space and time, decided for mysterious reasons to create the world. In most creation narratives, the absolute power separates light and shadow, cold and hot, man and woman, i.e. it polarizes reality: only a transcendent power that exists beyond the separations that we perceive in everyday reality can possibly create this reality .
Science has slowly but surely advanced into the once exclusive territory of religion. It is now perfectly legitimate to explore questions related to what I call the “three origins”: cosmos, life and spirit. In fact, for many scientists, these are the most fascinating questions. How far can science go to explain the origin of the universe, the origin of life, and the existence of consciousness? Today I wanted to say a few words about the origin of space and time, also known as the Big Bang.
During the 20th century, our knowledge of the universe experienced an extreme revolution. In 1924, the American astronomer Edwin Hubble showed that the Milky Way, our home galaxy, is one of billions of others separated by millions of light years. In 1929, Hubble revealed to the world that the universe was expanding: these galaxies were moving away from each other at increasing speed. Soon this expansion was interpreted as the expansion of space itself: contrary to popular belief, galaxies are not like fragments of an explosion, but are swept away by the expansion of space itself. As Einstein’s general theory of relativity has shown, space (and time) is plastic and can be stretched like a rubber band. If we play the movie backwards as we go back into the distant past, galaxies move towards each other until they lie on top of each other: matter reaches enormous densities and pressures and the temperature rises. In the beginning of time the universe was incredibly hot and dense. It is this initial state, very unstable, that triggered the expansion of space that we call the Big Bang.
In truth, things are not that simple. Perhaps even before that there was a phase we call inflation, when the universe expanded at speeds greater than that of light. But let’s stay with the cosmos around 1970 for the time being. (I’ll get to the next 40 years soon enough.) The question then is, ok, but how did this compressed ball of matter come about?
It gets chaotic here. Classically, the theories we use to describe the primeval fireball break down. Energies go into infinity, the “size” of the universe approaches zero. Obviously something is wrong. And it is wrong that one cannot describe the origin of the universe with classical theories. You have to factor in quantum effects. The problem is that we don’t have a theory that links classical gravity with quantum mechanics. Its leading competitors, superstrings and loop quantum gravity, are still a long way from providing answers. Nevertheless, we know that space-time was quantum mechanical in the beginning. As such, energies can fluctuate according to the principle of uncertainty and, amazingly, the universe itself can be a quantum fluctuation with zero energy: the scientific version of creatio ex nihilo. Space emerges from the quantum nothing. Suppose we have a theory that does this in an acceptable, empirically validated way. Is that the solution to the origin of the universe? I would say it’s a solution, a scientific version of creation. It turns out that science needs a framework, a framework in order to function: principles, laws, concepts like energy, space, time, matter. It is always possible to see reality beyond it all, beyond the reach of scientific conceptualization. In other words, since science cannot explain itself, it cannot fully answer the question of the origin of all things. Unless science naturally becomes something new, capable of developing the “theory of theories”, that even explains why there is such a thing as science and a universe that obeys certain rules and not others. But that seems very far away.