SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/astro-universe-age

About how old is the universe?

The universe is about 13.8 billion years old.

Start playing free

  1. 4.6 billion years
  2. 138 billion years
  3. 13.8 billion years ✔

Why: Cosmological expansion, the cosmic microwave background, and the universe's contents constrain its history. The best broad estimate is about 13.8 billion years.

Huh, didn't know that: This age is roughly three times the age of Earth.

The dad joke
At 13.8 billion years, the universe has stopped counting candles.
Like this card?
Play the game

References

Answer: 13.8 billion years. Cosmological expansion, the cosmic microwave background, and the universe's contents constrain its history. The best broad estimate is about 13.8 billion years.

  1. Astronomy 2e Chapter 29 Summary openstax.org/books/astronomy-2e/pages/29-summary
    Observations tell us that the expansion started about 13.8 billion years ago.
    Checked 2026-10-10.

Think this answer is wrong? Tap "Challenge this answer" on the card in the game and tell us why.

Test yourself in the game

Astronomy & SpaceDid the Big Bang occur at one location inside preexisting space?Astronomy & SpaceAbout what fraction of cosmic critical density is dark matter?Astronomy & SpaceWhat observed cosmic behavior is attributed to dark energy?

That's stuff everyone should know.