An interactive companion to the sky-colour reconstruction. Scrub the timeline to watch the atmosphere change from the steam-and-CO₂ Hadean to today, then pick an epoch and scrub through a day to see how its sky moved from dawn to dusk. Every colour comes from the same spectral radiative-transfer model as the report.
Four and a half billion years
The globe is seen from space at equinox with the Sun behind you, so latitude runs from the equator at the centre line to the poles at top and bottom. The atmosphere is drawn 30× too thick so that altitude structure shows.
Noon sky, zenith at top and horizon at bottom, at the equator, mid-latitudes and the summer pole; the Sun's disc in its own colour and brightness. Brightness relative to today's clean sky.
A day under that sky
A whole-sky (fisheye) view: the zenith is at the centre and the horizon is the rim, north at the top. Equinox geometry, so the Sun rises due east at 6:00 and sets due west at 18:00 everywhere; at the poles the noon Sun sits only 15° above the horizon.
Sky along the Sun's vertical: from the horizon under the Sun, up through the zenith, down to the opposite horizon.