The age of the universe, as currently estimated by scientific consensus, is approximately 13.8 billion years. This value is derived from a combination of observational data and theoretical models, including measurements of the cosmic microwave background radiation, the expansion rate of the universe, and the abundance of light elements.
It's important to note that this age is determined within the framework of the Big Bang model, which describes the evolution of the universe from an initial hot, dense state. According to this model, the age of the universe is measured from the moment of the Big Bang until the present time.
When you mention a hypothetical "outside view" or a "block universe," it seems you're referring to concepts related to the nature of time and the structure of spacetime. In the block universe or "eternalist" view, all moments in time, from the past to the future, exist simultaneously as an unchanging "block" of spacetime. This view suggests that the past, present, and future are all equally real and that time is merely a dimension within this four-dimensional block.
Within the block universe framework, the age of the universe would be considered a feature of our subjective experience within this spacetime block. However, it's important to note that the block universe perspective is a philosophical interpretation of the nature of time and is not yet established as a definitive scientific description.
While the age of the universe is currently estimated based on our understanding of its expansion and evolution, questions about the nature of time, its fundamental nature, and its relation to the structure of the universe remain active areas of scientific and philosophical investigation. Different interpretations and models are being explored to further our understanding of these complex concepts.