Why is it almost 2020 if humans have been on Earth for 200K years? | Just The FAQs

Humans have lived for over 200,000 years and yet the entire world agrees it's the year 2020. So, how did we get here?

The coming new year has been widely heralded as the start of a new decade: the 2020s. But an old timekeeping conundrum has led some to contend we're celebrating too early and that we should actually wait until Jan. 1, 2021. .

A decade is a period of 10 years — that isn't disputed. But a glitch in our calendar system creates a problem if you think decades should begin in years ending with a zero. If you continue the pattern back about 2020 years, you run into a major issue.

That's because there is no "year zero" in our calendar system, explained Craig Callender, a professor of philosophy at UC San Diego who has studied the physics and experience of time.

The lack of a year zero means the only consistent way to measure decades — or centuries or millennia — is to start them in years ending in one: That’s the theory presented in explanations of the debate published by the Farmer’s Almanac, timeanddate.com, the New York Times and others.

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