How old is the universe?

The best available information indicates that the age of the universe is 13.7 billion years. Hubble has helped to measure the age of the universe using two different methods. The first method involves measuring the speeds and distances of galaxies. Because all of the galaxies in the universe are generally moving apart, we infer that they must all have been much closer together sometime in the past. Knowing the current speeds and distances to galaxies, coupled with the rate at which the universe is accelerating, allows us to calculate how long it took for them to reach their current locations. The answer is about 14 billion years. The second method involves measuring the ages of the oldest star clusters. Globular star clusters orbiting our Milky Way are the oldest objects we have found and a detailed analysis of the stars they contain tells us that they formed about 13 billion years ago. The good agreement between these two very different methods is an encouraging sign that we are honing in on the universe’s true age.

HubbleSite and STScI are not responsible for content found outside of and

Next question: How big is the universe?

See all questions and answers on one big page.

Return to question list for Cosmology

Return to FAQ home