Three minutes to talk about popular science
When we look up at the starry sky and see those twinkling stars, have we ever wondered if the dark space behind them hides a larger, more mysterious, and more powerful existence than them?That is the black hole, one of the most mysterious objects in the universe, whose existence challenges our understanding of the laws of physics, and its interior is impossible for us to detect and understand. So, could the universe we live in be a giant black hole?Are we inside this black hole and unable to glimpse the truth from the outside?
To answer this question, we first need to understand what a black hole is, and its characteristics. A black hole is an extremely dense celestial body formed due to the collapse of gravity, and its density and gravitational pull are so strong that even light cannot escape. Thus, the surface of a black hole is like a boundary called an event horizon, which completely isolates the inside and outside of the black hole. The matter and information within the event horizon can never be known to the outside observer, and vice versa. That's why we can't directly observe the inside of a black hole, nor can we determine its structure and properties.
So, does our universe have similar boundaries?In fact, there is a theory that the edge of the universe is a structure similar to a black hole's event horizon, called the cosmic horizon. The cosmic horizon is the farthest distance of the universe that we can observe due to the expansion of the universe and the limitation of the speed of light. Beyond this distance, we will never be able to see because the light they emit will never reach us. In the same way, the light we emit can never reach them, which means that the exchange of information between us and them is impossible. It's as if we're separated from them by a ** wall, and this wall is the cosmic horizon.
If our universe has a boundary similar to a black hole, is our universe a black hole?There is no one definitive answer to this question because we cannot prove or disprove this hypothesis. We can only analyze its possibilities and plausibility based on our current observations and theories. Below, let's take a look at this issue from several aspects.
First, we'll see if our universe meets the definition of a black hole. A black hole is defined as a celestial body with a mass and density large enough that its gravitational radius is greater than its physical radius. The gravitational radius is the minimum radius at which the gravitational pull of a celestial object can bind light, which is the radius of the event horizon. Physical radius refers to the actual size of a celestial body. If the physical radius of a celestial body is less than its gravitational radius, then it is a black hole. So, does our universe meet this condition?
According to current observations, the mass of our universe is about 10,53 kilograms, and the radius of the cosmic horizon is about 4.6 billion light-years. If we look at the universe as a uniformly distributed sphere, then its density is about 99 10 -27 kg cubic meters. Based on these data, we can calculate that the gravitational radius of the universe is about 13700 million light-years, while the physical radius of the universe is about 9.3 billion light-years. Obviously, the physical radius of the universe is much larger than the gravitational radius of the universe, and therefore, the universe does not meet the definition of a black hole.
Second, we're going to see if our universe has the characteristics of black holes. The black hole is characterized by the presence of a singularity inside it, a point of infinite density, infinitesimal volume, and infinite curvature, where the laws of physics fail. In the vicinity of the singularity, the structure of space-time will undergo extreme distortions and changes, resulting in some strange phenomena, such as the reversal of time, the reversal of space, the reversal of cause and effect, etc. So, does our universe have similar singularities and space-time distortions?
According to the current theory, our universe is triggered by a big **, which is the origin of the universe and the singularity of the universe. Before the big **, the universe was a state of infinite density, infinitely small volume, and infinitely high temperature, and this state was a singularity, and it was also the place where the laws of physics failed. After the Great **, the universe began to expand rapidly, and space-time began to form and evolve. In the early days of the universe, the structure of space-time was very unstable and chaotic, with many quantum fluctuations and singularities, such as wormholes, surges, dark energy, etc. These phenomena all show that there are indeed singularities and space-time distortions similar to black holes in the interior of the universe.
Finally, we'll look at whether our universe could be a black hole in another universe. This question touches on a broader topic, the multiverse hypothesis. The multiverse hypothesis is that the universe we live in is not unique, but that there are many parallel universes, which may have different physical laws, different histories, different structures, different dimensions, and even different logics. These parallel universes may or may not be connected, may or may not affect each other, or may be isolated from each other.
To sum up, there is no definitive answer to the question of whether our universe is a black hole, and perhaps never will be. We can only explore and speculate on the nature and structure of the universe based on our observations and theories, but we must also realize that our knowledge and understanding are limited, and we may never be able to break through the limits of the cosmic horizon, and we may never be able to uncover the ultimate mysteries of the universe. However, this does not prevent us from being curious and exploring the universe, because the universe is always full of wonder and beauty, and it can always bring us new inspiration and insights.