It’s safe to assume that we’ve all experienced a coincidence or two in our day-to-day lives before, but for the most part, these occurrences are inconsequential. In fact, coincidences are guaranteed to happen all the time, given that there are many, many events occurring, however, some are much less likely to occur.
Take the many coincidences that allowed all of life to exist, and even the entire universe to exist, for example. Had these events never happened, not a single living thing would roam the Earth, nor any other planet for that matter.
As such, these aren’t you’re average, run-of-the-mill coincidences; these are universal lotto tickets, and our universe has certainly won the lottery.
The first of these great coincidences to occur was during the earliest period of the universe’s existence: the Big Bang. Just after the Big Bang occurred, according to the models that we’ve developed today, the energy density of the Big Bang and it’s rate of expansion would have to be proportioned just right to prevent either a “great crunch” or “great dissipation” from happening. In the case of the former, if the energy density is too high, the universe will collapse into itself; in the case of the latter, if the energy density is too low, stars and subsequent galaxies will not form.
However, as luck would have it, the universe we inhabit exists on a razor’s edge found within the sweet spot between the two extremes: not too dense and not too dispersed. This specialized zone is referred to in scientific jargon as W=-1. Unfortunately, those same models that discovered this coincidence also determined that our universe’s place in this zone is an unstable one, with a slight deviation in said value that would ultimately spell disaster for the entire cosmos.
The Higgs Boson, otherwise known as the “God Particle”, or the particle that is responsible for the mass of the universe, is another coincidence worth mentioning. If its mass were much less than what it is, than the universe would be engulfed by what physicists refer to as a true vacuum.
As the theory states, the true vacuum is the universe in it’s most stable, low-energy state; the kind you don’t want if you’d like to exist. The false vacuum is the one we live in today, existing in a meta-state. Given enough energy (or a change in the mass of the Higgs Boson, as stated before) this meta-state can be knocked off balance, tumbling the universe into a true-vacuum. Known as vacuum decay, this would be a serious problem for the false-vacuum universe that we inhabit, in fact, the consequences would be catastrophic. At the speed of light, a bubble of true vacuum would cross the observable universe, destroying everything in its path. Not a living soul would survive; alien, human, or otherwise.
Frightening, but the terrors don’t end there. The weight of the proton, and the Fine Structure constant are two more precarious constants of the universe. If the proton were sufficiently heavier than a neutron, the proton would become unstable. Our understanding of chemistry as a result would be entirely different.
As for the Fine Structure constant, (the value of which characterizes the strength of the electromagnetic interaction) if it were off by a mere four per cent, carbon would not have been produced through stellar fusion, and therefore carbon-based lifeforms would not exist.
Water, the essential ingredient to life, is yet again, another coincidence; albeit, an incredibly strange one. As neutral and devoid of character as it may seem, water is actually a very unique molecule. In fact, it is the only one whose liquid form is more dense than it’s solid form, causing, ice, the solid form of water, to float. Because ice floats, life found within bodies of water can survive beneath the ice through periods of extreme cold (winter seasons, ice ages, etc.). If it did not float, the ice would collect on the sea floor, leaving no room for life to survive.
One of the more terrifying, and close-to-home (relatively speaking) coincidences is that of the asteroid that hit the Earth 66 million years ago. It is widely agreed that it was an asteroid that caused the extinction of the dinosaurs. As we have discovered, the sedimentary layer associated with the final age of the dinosaurs 66 million years ago contains an iridium deposition that is likely the result of an extra-terrestrial impact. This evidence is further corroborated by the Chicxulub crater, otherwise known as the impact crater of that very same asteroid.
Okay, maybe you already know this, but did you know that In spite of the destructive consequences of this impact, had the asteroid not arrived when it did, it may have not resulted in an extinction event?
This is due to the fact that at the time, dinosaur ecosystems were weakened by a loss in diversity. This loss, coupled with the asteroids impact, are what together pushed the global dinosaur population into extinction.
And as we’ve come to learn, through adaptive radiation, the small mammalian creatures that survived the impact proliferated into a wide variety of new species, a sudden diversification that could only be expected after so many ecological niches were left vacant by the dinosaurs. This diversification eventually led to the human species.
So, in effect, we owe our existence to that asteroid, and more specifically, the impeccable timing that it had.
It sounds baffling, and even somewhat terrifying to imagine that our universe would not be as it is today had these chance occurrences not happened, but one can take solace in knowing that they would have eventually happened anyways, if one is a proponent of eternal inflation theory.
As the American theoretical physicist Paul Steinhardt first described in 1983, eternal inflation is the theory that many universes inflate infinitely into existence, each with their own values associated with physical constants. Therefore, it is of no surprise that eventually, the right combination of constant values would arise out of the infinitely “bubbling” universes, producing the conscious life that is capable of asking these questions. Those universes that did not have the correct combination of values did not support life (or at least, life as we know it), and that is why our universe does; because we are here.
As Murphy’s law states, anything that can go wrong, will go wrong eventually; but the more appropriate observation would be to state that given enough time, anything that can happen will happen eventually. Therefore, given enough universes and enough time (as eternal inflation theorizes), the possibility of our seemingly impossible universe, with it’s many, many coincidences, becomes an absolute guarantee.