According to current astronomical data, approximately how old is the universe?

• A. 4.5 billion years
• B. 14 billion years
• C. 1 billion years
• D. 100 billion years

Answer: (B)

The age of the universe is determined by the expansion history of the cosmos, inferred from precise measurements of the cosmic microwave background and the current rate at which galaxies recede. Using these data with the standard cosmological model, the timeline traced back to the Big Bang ages the universe at about 13.8 to 14 billion years. In context, 4.5 billion years is roughly the age of Earth, not the cosmos. 1 billion years is far too young given the observed expansion history, and 100 billion years would require a slower expansion than what we observe. So the ~14 billion-year figure best matches current astronomical data.