The age of the universe is approximately

• A. Fourteen billion years
• B. Four trillion years
• C. One hundred million years
• D. One billion years

Answer: (A)

Understanding the age of the universe is about tracing how long cosmic expansion has been happening and how the hot Big Bang cooled over time. By combining the observed expansion rate with measurements of the cosmic microwave background and the ages of ancient stars and galaxies, scientists place the universe’s age at about 13.8 billion years, commonly rounded to roughly fourteen billion. This is why the correct choice is the one that reflects a very old, multi-billion-year timescale. The other options would imply ages that conflict with what we observe—trillions of years would be older than our models allow, while hundreds of millions or a single billion years are far too young given ancient cosmic objects.