What you see
Between the ignition of the Sun, where Laniakea ends, and the first frame of Earth lie some four billion years that Numen does not show: the planet’s formation and the birth of the Moon, the first life, the oxygen coming into the air, the long snowball glaciations. It is a deliberate ellipsis. Earth begins about 540 million years ago, in the Cambrian — where the fossil record fills with complex life, and where the palaeogeographic models the globe is built from begin.
The centre wall is a globe, and every frame of it is a reconstruction. The surface is built from the PALEOMAP palaeo-elevation models (Scotese & Wright, 2018) — the height of the land and the depth of the sea across the last 540 million years — reconstructed through time with the PALEOMAP plate model (Scotese, 2016), in 2,161 steps a quarter of a million years apart. The continents are not drawn by hand. They go where the reconstruction puts them.
The colours are climate: temperature, rainfall, snow and sea ice from palaeoclimate simulations run for each stage (Valdes, Scotese & Lunt, 2021), so ice spreads where the model froze and deserts open where it dried. A few things are choices rather than measurements — the height of the ice, how far the sea falls at the end — and so is the pace. Time slows as it nears the present, so the last 66 million years are not over in a blink.
Australia begins inside Gondwana, a shallow seaway across its heart. On the side walls, moments from the fossil and geological record surface and pass, each riding a scrolling axis of deep time at its age — fifty-one of them in all. The images are imagined: generated from descriptions of the record, not photographs of it.
Ice comes and goes. Three hundred million years ago Gondwana lies under the greatest ice of the journey — the white is where the climate model froze.
An inland sea floods the interior. Australia is still joined to Antarctica, and forests — and the dinosaurs that lived in them — endure months of polar dark inside the Antarctic Circle.
Then Australia tears away. The Southern Ocean opens behind it, a current closes around the pole, and Antarctica freezes. The continent drifts north into warmer latitudes and a drying heart.
At the end the sea falls, the shelf is laid bare, and Australia, New Guinea and Tasmania are one land — Sahul. No people appear in Earth. At the last, only footprints on a shore.
