As a science fiction writer, I enjoy coming across science articles that make me a better world builder, so I read with interest Rene’ Heller’s article “Better than Earth” in the January 2015 Scientific American.
In this piece, Heller makes the case that Earth is past its prime and only marginally habitable. He asks us to consider the deserts, polar regions, and deep ocean. They are poorly populated at best. Heller says that the Earth’s prime habitable years occurred during the Carboniferous period. That made me smile because I had the Carboniferous in mind when I designed First Egg (homeworld of the Imperium). For example, feudal Imperial society had to be very careful with fire (due to the high oxygen content of the atmosphere) and preferred to light their dwellings with luminescent powders.
Heller argues that worlds ideally suited for life would be somewhat larger than Earth – perhaps up to twice Earth’s mass. This could lead to a higher surface gravity and a thicker atmosphere, both of which could cause a flatter topography: an “archipelago” world with shallower seas and smaller continents or only island chains. I found that an interesting point, since archipelagos and tidal pools are so conducive to a variety of life forms. Another benefit to a larger planet would be a longer-lasting core which could generate a more powerful magnetic field around the planet to better protect any life from destructive cosmic rays.
The author adds that an ideal “nursery” planet would circle a K dwarf star because those stars shine steady for billions more years than our sun, giving life better odds to develop and grow. Sentience is more likely to arise in such conditions.
Heller includes other variables, such as axial tilt, plate tectonics, and habitable surface area. He also discusses one prime possibility found by the Kepler telescope: Kepler-186f.
Perhaps as our sun ages, pushing its habitable zone further out beyond Earth’s orbit, we will discover worlds even better suited for life than the one we started on.
vlsperry 