Good thing we’re so careful about pushing limits, here on earth.
Box 1.1
Gravity and the habitability of Earth
Extreme tolerances of carbon-based metabolism are determined by the freezing point of water, Whose liquid form is required for the formation and reactions of organic molecules (the lower bound), and by temperatures and pressures that destabilize amino acids and break down proteins (the upper bound). Earth’s continuously habitable zone—the range of orbital radius ensuring optimal conditions for a life-supporting planet—is very narrow (Perkins 2013). A recent calculation concluded that we are even closer to the limit than previously thought: Kopparapu and co-workers (2014) concluded that, given its atmospheric composition and pressure, Earth orbits at the inner
edge of the habitable zone, just outside the radius where the runaway greenhouse effect would bring intolerably high temperatures.
From Energy and Civilization.
Good thing we’re so careful about pushing limits, here on earth.