Exploring Habitability Across the Multiverse
Is our Universe the only existing one or could there be multiple universes forming an all-inclusive multiverse? This is a question that many have pondered over, as it raises the possibility of there being other universes beyond our own.
What if these universes do exist? What kind of conditions would they possess, and could they support life? These are some of the questions that have been raised in the exploration of the concept of the multiverse.
While this idea may seem far-fetched, it is not as implausible as one might assume. My colleagues and I have been delving into the topic of other possible universes and examining how they can provide insights into the conditions that support life and how these conditions come about.
According to some physicists, the cosmic dawn of rapid expansion known as inflation makes the existence of some form of multiverse inevitable. This theory suggests that there are multiple universes, with each new universe emerging from the seething background of inflation, characterized by its own unique set of physical laws.
Assuming that the physical laws governing these universes are similar to ours, we can study them using mathematical equations. This enables us to gain a better understanding of these hypothetical universes.
In our Universe, physical laws dictate the interactions between objects, and constants of nature, such as the speed of light, determine the strengths of these interactions. We can envision alternate universes with different properties and explore their consequences using mathematical equations.
However, this is no easy feat as these rules form the basic structure of the Universe. For instance, if we were to imagine a universe where the electron is a hundred times heavier than in our Universe, it would have profound implications for stars, planets, and even life itself.
In a recent series of papers, we focused on the question of what life needs to exist and thrive. We examined this issue in the context of habitability across the multiverse, which is a complex concept that requires careful consideration.
One of the key ingredients for life is complexity. On Earth, this complexity arises from the combination of various elements of the periodic table, which can be arranged into an incredible array of different molecules. Essentially, we are complex molecular machines.
In addition to complexity, a stable environment and a continuous supply of energy are also crucial for life. It is no coincidence that life on Earth originated on the surface of a solid planet with a rich supply of chemical elements, illuminated by a stable star that has existed for a long time.
To investigate the possibility of similar environments existing across the multiverse, we first examined the abundance of chemical elements in our universe. All elements in our universe, except for hydrogen and helium, are produced by stars through nuclear reactions in their cores or in supernovae explosions.
These processes are governed by the four fundamental forces of the universe: gravity, electromagnetism, strong nuclear force, and weak nuclear force. Gravity compresses the stellar core, creating immense temperatures and densities, while electromagnetism tries to push atomic nuclei apart. However, the strong nuclear force can bind nuclei into new elements, and the weak nuclear force plays a role in the ignition of the stellar furnace.
The masses of fundamental particles, such as electrons and quarks, also play a significant role in the processes that govern the universe. By adjusting the dials that control these fundamental forces and particles, we can explore hypothetical universes and observe the changes that occur in the rest of physics.
To tackle the complexity of the problem, the researchers divided the different pieces of physics into manageable chunks, such as stars and atmospheres, planets and plate tectonics, and the origins of life, and then combined them to create an overall understanding of habitability across the multiverse.
A complex picture emerges, with certain factors having a strong influence on the habitability of a universe. For example, the ratio of carbon to oxygen, which is determined by nuclear reactions in the core of a star, appears to be particularly important. Straying too far from the ratio found in our Universe, where there are roughly equal amounts of both elements, could make it extremely difficult for life to emerge and thrive.
However, the abundance of other elements seems to be less important, as long as they are stable. The stability of these elements does depend on the balance of the fundamental forces, but they can play a significant role in the building blocks of life.
It’s important to note that while the concept of a multiverse is a fascinating idea to explore, it is still just a hypothesis and has not been confirmed by any empirical evidence. Additionally, even if the multiverse does exist, we cannot be certain that the physical laws of other universes are different from our own.
As scientists continue to study the universe and explore the possibility of a multiverse, it’s important to approach the topic with both curiosity and caution. We must remain open to the possibility of new discoveries, while also being rigorous in our methods and understanding the limitations of our current knowledge.