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Scientists have dedicatedly delved into the study of the universe’s essence. However, some venture even further into uncharted territories, contemplating what might exist beyond the fringes of our known cosmos. Is there a possibility that something lies beyond our realm of existence? Indeed, there are various theories about what this “something” could be.
The concept of “outside the universe” becomes elusive right from the start as we must first define the universe. A widely accepted definition is that of the observable universe, determined by the speed of light. Given that we can only perceive objects when the light they emit or reflect reaches us, our sight can never surpass the maximum distance light can travel within the time the universe has existed. Thus, the observable universe continues to expand but remains finite – often referred to as the Hubble Volume, in honor of the telescope that has provided us with our farthest glimpses of the cosmos. We shall never be able to behold what lies beyond this boundary, and as a result, it shall remain the only universe we shall ever experience.

The Observable Universe: What We Know
The question of what lies beyond the universe is complex, as it first requires us to define what the universe is. The observable universe, which is defined by the speed of light, is the commonly accepted answer. As we can only see things when light reaches us, we can never see farther than the farthest distance that light has traveled in the lifespan of the universe. As a result, the observable universe continues to grow, but it is finite – referred to as the Hubble Volume, named after the telescope that has given us the farthest views of the universe. For all practical purposes, this is the only universe we will ever know.
Possibilities of What Lies Beyond the Edge of the Observable Universe
There are several possibilities that scientists have theorized. These include:
Beyond the Hubble Telescope
Despite the finite boundary of the Hubble Telescope, scientists believe that there is more universe out there. Astronomers believe that space could be infinite, with matter and energy distributed much like it is in the observable universe. This theory has mind-bending implications for what lies beyond. Beyond the Hubble Volume, you wouldn’t just discover new planets – you would find everything, eventually. Every possible thing that can exist, from alternate versions of Earth to every action you’ve ever taken, will exist somewhere in the infinite universe. That might sound impossible, but infinity is a vast concept.
Relevant Article: Parallel universe Have astronomers found evidence of multiverse?
Gravitational Influence
One theory is that massive structures outside the Hubble Volume have a gravitational influence on our universe. This would suggest that the structure of the infinite universe beyond our view is not uniform. The structures themselves could be anything, from massive agglomerations of matter and energy to bizarre warps that channel gravitational forces from other universes.

Dark Flow
In 2008, astronomers discovered an unexpected phenomenon – all galactic clusters were streaming in the same direction at an incredible speed, over 2 million miles per hour. This was later confirmed in 2010 and referred to as Dark Flow. The movement defies all predictions about the distribution of mass in the universe after the Big Bang.
Infinite Bubbles
The idea of what lies beyond the Hubble Volume is somewhat of a cheat, as it is still technically the same universe, just a part that we can’t see. The laws of physics and constants would be the same. Another theory is that the post-Big Bang expansion of the universe resulted in the formation of “bubbles” in the fabric of space. Each bubble represents an area that stopped stretching and became its own universe with its own laws. Space is infinite, and so are the bubbles, so even if you could cross the boundary of our bubble, the space in between the bubbles is still expanding, so you would never reach the next one.
Black Hole Spawning
A theory proposed by physicist Lee Smolin, the fecund universes theory, suggests that each black hole in our universe creates a new universe with slightly different physical laws. Smolin suggests a form of natural selection for universes, where laws that lead to the frequent formation of black holes lead to the creation of more universes, while universes that don’t form black holes “die out.” This theory has since been discredited by Smolin and others.

Many Parallel Universes
There are many theories about parallel universes, but the most widely accepted one involves the evolution of string theory to include membranes that vibrate in other dimensions. These membranes are other universes, and when they collide, they create a new universe. The rippling motion helps explain the observed distribution of matter in our universe.
Conclusion
The edge of the observable universe represents a frontier of discovery, a place where we can explore the unknown and uncover the mysteries of the universe. Whether it be another universe, a multiverse, or a void, what lies beyond the edge of the observable universe is a topic of ongoing study and speculation. As our technology continues to improve and our understanding of the universe expands, we can only hope to uncover more and more about the mysteries that lie beyond the edge of the observable universe.