Imagine that the age of the universe, 13.82 billion years, is compressed into only one year. Carl Sagan explains this idea (using 15 billion years as his example) in a clip from his 1980 television series, Cosmos: A Personal Journey.
Down here, the first humans made their debut around 10:30 p.m. on December 31st. And with the passing of every cosmic minute — each minute 30,000 years long — we began the arduous journey towards understanding where we live and who we are.
11:46 - only 14 minutes ago, humans have tamed fire.
11:59:20 - the evening of the last day of the cosmic year — the 11th hour, the 59th minute, the 20th second — the domestication of plants and animals began, an application of the human talent for making tools.
11:59:35 - settled agricultural communities evolved into the first cities.
We humans appear on the cosmic calendar so recently that our recorded history occupies only the last few seconds of the last minute of December 31st. In the vast ocean of time which this calendar represents, all our memories are confined to this small square.
Every person we’ve ever heard of lived somewhere in there. All those kings and battles, migrations and inventions, wars and loves. Everything in the history books happens here, in the last 10 seconds of the cosmic calendar.