The universe is about 13.8 billion years old

Ask how old everything is and you get a surprisingly precise answer: about 13.8 billion years. That figure comes from carefully measuring the cosmic microwave background, the leftover light from the Big Bang, and feeding its tiny temperature ripples into models of how the universe has expanded and cooled.

NASA’s WMAP satellite nailed the age to within half a percent, and Europe’s Planck mission, with its sharper map of that ancient light, refined the value to roughly 13.8 billion years. The two missions used different instruments and were launched years apart, yet they agree closely — exactly the kind of cross-check scientists like to see before trusting a number.

For perspective, our Sun and Earth are only about 4.6 billion years old, so the cosmos had been running for some nine billion years before our solar system even formed.

The matter making up your morning coffee was forged long after the universe got going.