The clock of life.

Step 1 of 6

A day of history

The Earth formed about $4540$⁠ million years ago. A number like that is hard to feel, so the Scene squeezes it into one day: the Earth forms at midnight, and the present is the next midnight. Each hour is then about $189$⁠ million years, and each minute about $3$⁠ million.

To place an event on the clock, ask what share of the Earth’s history has already gone by: an event $A$⁠ million years ago sits at $\dfrac{4540 - A}{4540}$⁠ of the day. Through time is at Earth forms.

Step 2 of 6

Animals come late

Through time is locked at First animals, about $575$⁠ million years ago: soft, leaf-like creatures on the sea floor. Look how much of the dial the hand has already left behind. After them, $538$⁠ million years ago, comes the Cambrian explosion, with shells, legs and eyes.

Step 3 of 6

Microbes alone

The first life, about $3500$⁠ million years ago, was single cells with no nucleus, like today’s bacteria. Cells with a nucleus appear about $1800$⁠ million years ago, and many-celled life, red seaweeds, only about a billion years ago, at Many cells. Move Through time between First life and Many cells, and see how much of the day goes by.

Step 4 of 6

A year of history

Now Squeeze it into is at One year: the Earth forms at midnight on 1 January, and the present is the end of 31 December. Each day of the calendar is about $12.4$⁠ million years. Through time is at Plants on land, $470$⁠ million years ago.

Step 5 of 6

Dinosaurs, mammals and us

Dial shows is at Last 70 million, so the end of the year is magnified, and Through time is at Asteroid: $66$⁠ million years ago an asteroid wiped out the dinosaurs, except the birds, their living descendants. The first dinosaurs appeared about $230$⁠ million years ago, and the first mammals soon after.

Step 6 of 6

The last seconds

Through time is locked at Our species, Homo sapiens, about $300\,000$⁠ years ago. On the day of history, each second is about $52\,500$⁠ years.