What is the estimated age of the universe?

The estimated age of the universe is approximately 13.8 billion years. This conclusion is based on extensive astronomical observations and data analysis, particularly through the study of cosmic microwave background radiation, which provides a snapshot of the universe shortly after the Big Bang. Furthermore, measurements of the expansion rate of the universe, known as the Hubble constant, along with observations of the oldest known star clusters, help to converge on this figure.

The age of roughly 13.8 billion years is widely accepted in the scientific community and is supported by various lines of evidence from astrophysics and cosmology. Stable estimates, derived from the Lambda Cold Dark Matter cosmological model and observational data from missions like the Planck satellite, corroborate this age determination.

Other choices, such as 4.5 billion years, refer to the age of the Solar System rather than the universe itself. Similarly, figures like 10 billion and 20 billion years either underestimate or overestimate the true age based on current scientific understanding and evidence. Thus, 13.8 billion years is a well-supported and accurate approximation of the time elapsed since the inception of the universe.