We think that the universe began with an explosion – a bang, but actually the early universe was like a nervous kid performing on stage for the first time. It took its time until every piece fit together perfectly. Billions of years later, we see a cosmos that fits human life perfectly – in fact, too perfectly.
There is no possible way to explain why the universe has everything in place so precisely. It’s as if Alan Turing managed to build the universal Turing machine by joining random wires and hoping for the best. But how do you get billions upon billions of cosmic bodies governed by precise mathematical laws all from a cosmic explosion? How does order come out of chaos?
In physics, the riddle of why the random universe fits together so perfectly is known as the fine-tuning problem. The universe extends 46 billion light years. As the early universe expanded, it began to form according to specific rules that we call the constants of nature.
The problem is, the order and pattern had to come from somewhere, and the only somewhere anyone can prove is the big bang. But the big bang was totally chaotic until suddenly it wasn’t.
The physics community accepts that fine-tuning exists. Even a minutiae variation in gravity, mass or electric charge would have caused the baby universe to either collapse in on itself or fly apart too fast for atoms to form. Supernova explosions that occurred billions of years ago are responsible for creating all of the heavy elements in nature, such as calcium, phosphorus, iron, and cobalt to name a few. Gravity caused the atoms of these elements to clump together and eventually they wound up inside an ancient solar nebula where all the planets, including our own, formed. Iron that makes up your blood came from a supernova that exploded eons ago.
The specifics of the explosion are determined by the strong force. If this force were different as little as 2% percent, there would have been no supernova explosions, no formation of heavy elements and therefore no life as we know it. The Earth (out of all the places in the universe) exists in the Goldilocks zone, where the conditions for life are perfect. The sun happens to emit most of its radiation in just the right part of the spectrum for the plants to feed on. The gravitational constant, the speed of light, Earth’s rotation, the decay rate of atomic particles, the rate of inflation, the big bang ripples, the uncertainty magnitude – all are in the exact order of magnitude for life to exist. In the case of gravity, variation of even 1/10^100 percent would have made life impossible.
In fact, Stephen Hawking wrote, “If the rate of expansion one second after the big bang had been smaller by even one part in a hundred thousand million million, the universe would have re-collapsed before it ever reached its present size.” How can the universe with its millions of processes be so accurate in all? How is the universe so fine-tuned? Are these just coincidences?
Coincidences aren’t science. Most of the scientific community believes in fine-tuning and backs it up with the anthropic principle. The anthropic principle, presented first by Brandon Carter in 1973, claims that there can be no knowable universe without human beings. The evolution of the cosmos must necessarily lead to conscious beings. This principle allows Earth to stop being a random speck of dust afloat in the cosmic ocean.
Consider the process of the creation of DNA. DNA took 3.7 billion years from the first prototypes and 10 billion years of cosmic existence to reach this point. On the way it took 3 million irregularities and alterations along with the mutations caused by cosmic rays and produced life. Casts doubts, doesn’t it? Physicists like Paul Dirac have also tried to put the anthropic principle in mathematical terms.
According to the anthropic principle, the universe is self-organizing, driven by its own working process. Each new creation of layer must regulate to the prior layer. It does not give us an answer to why the constants or other factors have such values, but it does tell us that it is not just a coincidence and we may one day solve it mathematically.
Viewed this way, fine-tuning does not seem like a mystery. No one finds anything mysterious about how the train gear in a car’s transmission fits together precisely. If it didn’t, the car couldn’t operate. Same way, the operational universe must be fine-tuned.
On the other hand, another view is that fine-tuning is just a case of coincidence piled higher and higher. The only explanation is that humans happen to exist in the right place at the right time. This is called the multiverse solution. It states that there are 1^500 universes – a number greater than the number of atoms in the universe – with different laws and we happen to exist in this one which turned out to be perfect. There is nothing special in the creation of humans or the universe.
This viewpoint is favored by string theory proponents including Stephen Hawking. This path has no concrete evidence but a lot of possible outcomes.
Do humans exist on the planet by sheer luck? Or do we exist because it was the main aim of the universe? Most people answer according to their worldview, which can be scientific or religious or a blur of both. Yet one thing is certain. We participate in the universe by finding patterns and where they come from – a goal worth pursuing for a lifetime.