As a sun ages and evolves, so do its planets. Gaian worlds perhaps evolve more than most, simply because their delicate biospheres transform and fade, an effect which influences the entire world. As the sun brightens, the oceans begin to evaporate, plunging the world into a Pelagic type world, where the atmosphere has thickened greatly and merges almost imperceptibly with the 200 degree oceans. But a critical point is eventually reached where there is catastrophic atmospheric and surface water loss. The sheer heat of the sun drives away the protective atmosphere, the oceans dry, and what is left is a desert world with only deep basins of highly saline seas, seas that have lifetimes measured in the thousands of years. A highly evolved PostGaian world will be completely waterless, its atmosphere a relic of its habitable past.
The geologic cycle of these worlds has largely ceased, although some remaining volcanism and minor tectonic activity might linger, slowly turning the atmosphere unbreathable as carbon dioxide begins to build. Life remains on the planet, reduced to extremophiles, huddled beneath the surface, away from the deadly heat, perhaps sequestered in underground oases where large amount of liquid water are preserved.
But the life of the planet is limited, and the ever growing sun, as it leaves the main sequence and becomes a subgiant star, roasts the world until finally it becomes a completely transformed planet, utterly devoid of life and maintaining an atmosphere formed through the capture of hydrogen and helium from the intense solar wind.
A PostGaian world, with the last remnants of an ocean visible, but not long for existence (image used courtesy Don Edwards).
Looking down into the remains of an ocean, the terraced cliffs of a former oceanic trench rising into the sky. For billions of years, this scene was more than a mile underwater. now, it bakes in the increasing sun.
PostGaians of Note
TV and Movies
Return to the PCL Index Page
Return to the ArcBuilder Universe Index
Return to Explorations
Questions and Comments? Email Me