The apparent discrepancy between the age of the universe and its size is due to the expansion of space itself. The concept of the observable universe and the measurement of its size can help explain this.
The age of the universe is estimated to be around 14 billion years based on various measurements, such as the cosmic microwave background radiation and the observed rate of the universe's expansion. This age represents the time since the Big Bang, which is considered the beginning of our universe as we currently understand it.
However, the observable universe is not limited to a sphere with a radius of 14 billion light years centered on us. This is because space itself has been expanding since the Big Bang. As a result, the light from distant objects has had more time to travel to reach us, and during that time, the space between us and those objects has expanded.
The current understanding is that the universe has been expanding at an accelerating rate due to a phenomenon called dark energy. This expansion means that the distance to objects that were initially close to us has increased over time, even though light from those objects has reached us.
As a result, the observable universe is larger than the 14 billion light years we might expect. The current estimate for the size of the observable universe is around 93 billion light years in diameter. This size takes into account the expansion of space that has occurred over the 14 billion years since the Big Bang.
It's important to note that when we talk about the size of the universe beyond the observable universe, we enter the realm of theoretical cosmology, and our knowledge becomes more uncertain. The observable universe represents the portion we can observe based on the current age of the universe and the speed of light. The size of the entire universe, beyond what we can observe, is still a subject of ongoing scientific research and investigation.