All together we're 553 billion years old. (25 sec)

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According to the United Nations estimates, the current global population is around 7.9 billion people. Let's assume an average life expectancy of 70 years for simplicity.

Collective age ≈ Global population × Average life expectancy

Collective age ≈ 7.9 billion × 70 years

Collective age ≈ 553 billion years