The question about what exists at the expanding edges of the universe is a topic of ongoing scientific investigation and speculation. The nature of the universe beyond our observable limits is still not fully understood. However, based on current understanding, there are a few key points to consider:
Observable Universe: The observable universe is the portion of the universe that we can detect and study. It is limited by the speed of light and the age of the universe. The light from distant objects takes time to reach us, so our observations provide a snapshot of the universe as it existed in the past. The observable universe is estimated to be about 93 billion light-years in diameter.
Expansion of Space: According to the Big Bang theory, the universe is continuously expanding. It is important to note that the expansion of the universe is not like an explosion in space; instead, it is an expansion of space itself. As space expands, galaxies, clusters of galaxies, and other structures move away from each other.
Cosmic Microwave Background (CMB): The afterglow of the Big Bang is known as the cosmic microwave background radiation (CMB). It is a faint, uniform radiation that permeates the universe and is visible in all directions. The CMB is considered the oldest light in the universe, dating back to about 380,000 years after the Big Bang. It is not an "enormous, infinitesimal amount of incredibly bright light" but rather a low-energy radiation that has cooled over time.
Beyond the Observable Universe: Beyond the observable universe, there may be regions that are currently beyond our detection due to the finite speed of light and the expansion of space. It is uncertain what exists in these regions, and we can only speculate based on theoretical models and extrapolations. Some theories propose the existence of a "multiverse" or speculate about the possibility of other universes or dimensions beyond our observable limits.
It's important to remember that our understanding of the universe is continually evolving as new discoveries are made and scientific theories are refined. The exploration of the cosmos is an active area of research, and scientists are continually striving to uncover more about the nature of the universe and its boundaries.