Cosmology and our View of the World
Anthropic Principle & Multiverse Concept
Lead: Nicholas Fawcett &Natallia Leuchanka
Summary by Ryan Tebbetts
Anthropic Principle & Multiverses
When thinking about the origin of man, it is hard to picture a universe that is not exactly like the one we occupy. It is even harder to imagine how this universe ended up suitable for life (more specifically sentient beings) given the narrow parameters that must be met.
Today’s modern technology has allowed humans to get a better grasp of the cosmos in which they live and to make predictions and hypotheses about where life came from. Giordano Bruno was one of the first scientific minds to explain that Earth was not special in terms of planets, and that the Sun was just one in an array of millions of stars found in the Milky Way Galaxy. He made these claims before Galileo showed with his observations of Venus’ phases that Venus is indeed orbiting around the Sun, and therefore Earth must also orbit around the sun. From there, humans have determined that Earth may not be special as a satellite of the Sun, but it is special in its ability to accommodate living beings in our existence on this planet. Earth is situated just far enough from the Sun to receive the appropriate amount of energy (sunlight) but not too close as too cause extreme conditions such as on Venus – called the Goldilocks region. What does make Earth unique among the terrestrial bodies is that its mass (gravity), location in the Goldilocks region and presence of its moon allow for the essential water to be present in the three phases. So, it is assumed possible that some other planets in the entire universe might have similar conditions under which life can prosper, like it has here on Earth. Then that leads to the question, are there other forms of life in the universe, not found on Earth? Specifically, is life probable under specific conditions, or is it so special as to only have arisen once? Without observationial evidence, it may seem that life on Earth is the only life in this universe. And even if life is found in the rest of our solar system or in the galaxy, it is still possible that life originated in one place and was dispersed throughout the galaxy. This leads back to the question, what is the origin of life?
Modeling of the universe with variations of the strength in the four fundamentals forces has shown that the stability of the structures essential for life forms depend on the delicate ratio between the fundamental forces - the strong and weak nuclear force, gravitational force and electromagnetic force. Any change in the ratio of these forces results in a universe that is not capable of sustaining life as we know it. This discovery has led to the formulation of the weak/strong anthropic principle. These principles postulate the prerequisites capable for evolution of life – of us. Have we won the cosmic lottery? Or are we just the result of some experiment created by the GODS?
In other words, understanding that this universe is unique and special has led to postulate two possible conclusions. The first is that we are the product of a series of random events dating back to the origin of the universe, the big bang. Each atom within the primordial soup was randomly aligned but when the expansion began, these atoms went on a trip through the universe to end up forming our solar system, more specifically Earth, and even more specifically us. This mode of thinking assumes that there are multi-universes or a multiverse for which each has its own big bang and therefore its own random atom arrangement with its own governing laws and principles. This concept is called the weak anthropic principle. It just so happens that this universe (that we reside in) expanded to form the laws which make our lives possible – the laws are almost too perfect to be a random coincidence; too perfect to allow the random primordial soup to evolve into life as we know it. Complementary, an alternate conclusion, called the strong anthropic principle, implies that there is a higher power or a not yet discovered physical law at work, controlling all of the variables that make life viable in our universe and then on our planet. Again, this concept presents even bigger questions such as does this higher power have an agenda? Is it even possible to define this power, this god? (Meant in a non-theological sense of the word)
Going, on from the very beginning, it has been shown that the early universe was primarily hydrogen and helium, the first two elements of the periodic table. As the elements expanded exponentially with the big bang, it formed stars from the immense energy and gravitational pull of the clusters of mass. But how were the rest of the elements formed if only hydrogen and helium were the only two elements available? Stars are a type of natural nuclear fusion reactors in that they cause collisions between atoms not possible in lower energy bodies. These collisions are what created the new heavier elements. In the example of carbon, it takes three alpha particles (helium atoms) to collide at the exact same time or a stable intermediate product. The problem is that the stages that lead up to the formation of carbon are very unstable and would require external forces to stabilize the particles during this process. However, it was found that the intermediate product provides what is known as a “resonance” for the capture of the third alpha particle – thus , which wwas later verified with tests at a particle accelerator. It just so happens that the weak nuclear force that makes this process possible has the specific strength, which was in place at the beginning of the universe.
Examining the observable universe as a whole, it is possible to estimate the amount of matter and energy (matter and energy are related by E=mc2). An addition to the visible matter, the CMB (cosmic microwave background) allows for the calculation of the “stuff” between the clusters of matter. This “stuff” has been formally called dark matter. As visible matter pulls on other visible matter by the force of gravity, dark matter does the same, but dark energy repels matter by a force opposite of gravity. If the sum of all mass (ordinary matter, dark matter, and dark energy) outweighed the observed state of expansion (or vice versa) then the universe would display a curvature in either direction. Scientists have found to an accuracy of 2 percent that the universe is flat. (Davies pg 42-43) Tying this concept in with the anthropic principle brings up more questions about the universe. Is this universe built for the purpose of supporting/breeding life? Are we a result of a universe that has found stability for a long enough time to allow for the creation/development of life forms to question the existence of being? Are we just plain lucky to find ourselves in a situation that has been 14 billion years in the making to experience a unique phenomenon known as life?
If we are a coincidence of a series of random events caught in a universe among other universes, then one can conclude that the next hierarchy beyond a universe is a multiverse. Each of these universes within the multiverse must have its own set of laws and parameters, unique to its own random series of events. For example, the mass of an electron is 9.1095 x 10-28 grams in our universe, but a different universe may have an electron being 8 x 10-27 grams. This type of thinking will lead to other parameters and physical laws being completely different. According to Paul Davies, there are approximately 10120 different ways to vary the governing constants in our universe. So along those terms, we just happen to find ourselves in a universe, among 10120 other universes, that is stable enough to allow the evolution of life and complex beings such as humans. Now if we try to model other universes that inherit different constants, it is unsure if life will be capable or even plausible for we only know how life is here, on Earth.
The symmetry of the universe shows us that at the beginning, when the universe was an infinitesimal point of matter/energy, it was simple and whole, due to its high energy. However, once it expanded and cooled, the universe broke symmetry and became complex and diverse, heterogeneous. So it may be possible that the way symmetry breaks results in new formations, specifically those associated with the parameters/forces that govern the universe today. Paul Davies gives an example of how high temperature creates symmetry while low temperature creates complexity. A magnetic bar of iron has small magnetic regions aligned so that they attract opposite poles and repel like poles. Raising the temperature, the small magnets point in all directions. This shows how symmetry is restored due to heat or energy. If the bar is slowly cooled back down, it will align the small magnets again to form the magnetic poles, if it under the influence of an external magnet. A similar situation is shown with the double helix DNA strain. It is a stable molecule with a right handed spin, but when the temperature is above 200 degrees Celsius, it just dissolves into the amino acids that make it up. These examples show us how the constants that govern universe may differ based on the expansion of each universe. Complexity is created at the start of the big bang and ultimately it creates the parameters for which the universe it defined.
Concluding, it can be said that the existence of this universe seems to be special in allowing for the creation of life and the evolution of complex life forms. Now this coincidence may be a result of one of many possible universes, or it may the results of some higher being, whom we as humans, have no possible way of determining. In any regard, we can agree that we reside in a universe whose parameters are suitable for life as we know it. This universe may one of countless universes, but it is clear that it carries the unique solution for the proliferation of life. It does seem too well built when considering how each of the fundamental forces acts in conjunction which each other to form a stable universe. Life may be a common occurrence throughout the universe, or life on Earth may be the rarest coincidence to ever happen. The Anthropic Principle the boundary conditions for the laws and constants that control our universe based on the fact that we came about to be here. Whether you believe in multiple universes (weak anthropic principle) or in the power of a greater being creating this universe for us (strong anthropic principle) it is certain that we should appreciate our place and cherish it. Regardless of our origins, this universe is the one were stuck with and I would not have it any other way.