According to theoretical physicist and super-genius Stephen Hawking, “The human race is just a chemical scum on a moderate-sized planet orbiting round a very average star in the outer suburb of one among a hundred billion galaxies.” Indeed, to most modern scientists we are nothing more than an entirely random ‘happy accident’ that likely would not occur if we were to rewind the tape of the universe and play it again. But what if that is completely wrong? What if life is not simply a statistical anomaly, but instead an inevitable consequence of the laws of physics and chemistry?
A new theory of the origin of life, based firmly on well-defined physics principles, provides hefty support for the notion that biological life is a “cosmic imperative”. In other words, organic life had to eventually emerge. If such a theory were true, it would mean that it is very likely that life is widespread throughout the universe.
And if this is in fact the case, those who love to speculate about the possibility of alien civilizations can rejoice in the fact that the odds that other sentient beings are out there has been increased. By how much would be difficult to calculate at this point, but all planets out there with a geochemistry that is sufficiently similar to Earth’s, orbiting a star at the appropriate distance, would be excellent candidates as breeding grounds for life. And once self-replicating life evolves, it could be just a matter of time before the components of a nervous system emerge.
The emergence of life in the universe is inevitable
The origin-of-life theory that made the news early last year, put forth by 31-year-old physicist and MIT professor Jeremy England, has some colleagues calling him the next Charles Darwin. Now that’s a pretty heavy comparison to live up to. The basic premise of the theory isn’t completely new though. The idea that biological life on Earth is an inevitable consequence of physical law had been put forth in very similar forms by Belgian physicist Ilya Prigogine and American biophysicist Harold Morowitz in the second half of the 20th century. But what makes England unique is that he seems to have come up with a simple mathematical principle that explains how the process might work. The notion that life is not just an unlikely cosmic accident, but instead a cosmic imperative, is based on one of the strongest principles in all of physics—the 2nd law of thermodynamics.
The 2nd law of thermodynamics may sound complicated but the underlying idea is actually pretty simple. The law says that entropy, which is just a mathematical term for disorder, must always stay the same or increase in a closed system. The most obvious example of a closed system is our entire (not just observable) universe. Nothing comes in or out of it, and over time it becomes more chaotic since the amount of disorder is always going up. Smashed plates do not reassemble themselves, hot things cool down, and melted ice cubes do not spontaneously reform.
But if disorder must always increase, how do you explain the emergence of life on Earth, which is very complex and ordered? For a time, Creationists eager to disprove science claimed that the existence of life actually disproves the 2nd law of thermodynamics. What Jeremy England’s origin-of-life theory shows is that rather than contradict the 2nd law, the emergence of life is actually driven by it.
Order from disorder
As explained, physics says disorder must increase in the universe overall, but that does not mean that parts of the universe can’t become more ordered. Living organisms are open systems that are said to be far from equilibrium. Such systems can take in energy from the environment to increase their internal order while increasing disorder in the closed system it belongs to. Therefore, complex life does not violate the 2nd of law of thermodynamics. In fact, it aids it by efficiently increasing entropy through capturing energy and dissipating it.
According to England, the fact that life is great at increasing disorder is an indication of a fundamental self-organizing principle in nature—a type of “cosmic evolution,” if you will. In a feature article on England, Quanta magazine explains his theory in a precise way:
“The formula, based on established physics, indicates that when a group of atoms is driven by an external source of energy (like the sun or chemical fuel) and surrounded by a heat bath (like the ocean or atmosphere), it will often gradually restructure itself in order to dissipate increasingly more energy. This could mean that under certain conditions, matter inexorably acquires the key physical attribute associated with life.”
The essence of this formula is captured well by a quote from Harold Morowitz in his influential 1968 book Energy Flow in Biology: “The flow of energy through a system acts to organize that system.” Since increases in a system’s organization increase its ability to generate disorder, living systems are favored by nature, given the right conditions. And the same general conditions as we see here on Earth are thought to be ubiquitous amongst the cosmos.
Darwin’s theory of evolution, which is governed by natural selection, explains how living species evolve over time, but it does not explain how life arose in the first place. England’s thermodynamic theory does not at all conflict with Darwin’s, but he suspects that natural selection is a special case of this more general phenomenon. And although evolution may have certain random processes at play, the emergence of life itself is not an accident, but instead inevitable. It is this inevitability that makes data-driven theories about extraterrestrial life significantly more plausible.
It is amusing to speculate about how far England’s entropy-driven life theory could reach. Wouldn’t intelligent life be best at extracting energy from the environment and dissipating it, and therefore highly likely to emerge due to the 2nd law of thermodynamics? Although precise figures would prove difficult to calculate, it certainly seems that humans use up a lot more energy than lower life forms. We can even take this one step further when trying to assess the likelihood of alien megastructures. Wouldn’t the use of giant solar panels to harvest energy by an intelligent species be a natural extension of the process whereby complex systems increase overall disorder?
The idea that there are other sentient beings out there far more technologically advanced than us is not only intriguing, but also increasingly probable based on what we have observed about our universe. As such, it may be time to no longer look at ourselves as just random accidents. Perhaps it’s just quixotic thinking, but I like to believe that this means we are living in a universe that is on our side.
I originally wrote this article for Raw Story.