The observable universe refers to the portion of the universe that we can potentially observe from Earth. It is limited by the distance that light, or any other form of information, has had time to travel since the Big Bang, given the age of the universe and the finite speed of light. However, it's important to note that the universe may extend beyond the observable universe.
The current estimate for the size of the observable universe is about 93 billion light-years in diameter. This value might sound contradictory since the universe is only about 13.8 billion years old. The reason for this apparent discrepancy is that the universe has been expanding over time. Due to the expansion of space, distant objects are moving away from us, and their light takes time to reach us.
To understand what lies beyond the observable universe, we need to consider the concept of the cosmic horizon. The cosmic horizon is the distance beyond which light (or any other information) has not had sufficient time to reach us since the beginning of the universe. Objects beyond this horizon are currently outside the reach of our observations.
It's important to note that the cosmic horizon is not a physical barrier or an edge of the universe. Instead, it represents a limit to our current observational capabilities. The universe could be much larger than what is currently observable, and there may be regions and structures beyond our cosmic horizon.
The ultimate extent and properties of the universe beyond the observable universe are still the subject of scientific investigation and theoretical speculation. Cosmologists continue to develop models and theories to better understand the nature of the universe at larger scales, but direct observational access to those regions is currently not possible.