Our Universe May Be One of Many
As a young boy, Brian Greene spent mornings mesmerized by two mirrors in his room that faced each other, creating an endless corridor of reflections. He often imagined a version of himself deep in that line of images who might act independently. This childhood fascination mirrors a profound shift in modern physics: the realization that our universe might be just one of many. For centuries, the word "universe" meant everything that exists. Today, that definition is shifting to accommodate the possibility that what we once considered the totality of reality is a single component in a vast collection of realms.
This shift is driven by the mathematical requirements of our most successful theories. Quantum mechanics, for instance, reveals a world of probabilities where we can only predict the odds of an event. One explanation for why we see only one outcome is that every other possibility occurs in its own separate universe. Similarly, if space is infinite, the laws of probability dictate that every possible arrangement of matter must repeat somewhere. Cosmology adds another layer through the theory of inflation, which describes a violent burst of expansion at the dawn of time. This process may be eternal, constantly spawning new "bubble" universes.
String theory further expands this by proposing that our world might be a three-dimensional "slab" or "brane" floating in a higher-dimensional space. These branes could even collide, triggering new big bangs and creating universes parallel in time. Some proposals even suggest that our experience is a holographic projection of information stored on a distant surface. While these concepts lack direct proof, they emerge naturally from the math used to explain our own world. Redrawing the boundaries of reality highlights the power of human thought to reach across the cosmos, marking our true arrival in the cosmic order.
Full summary available in the Readsome app
