Wednesday, July 2, 2014

Why we should colonize Venus, not Mars

The second planet from the Sun might seem like a nasty place to build a home, with a surface temperature hot enough to melt lead and an atmosphere so dense it would feel like being submerged beneath 3000 feet of water. But the air on Venus thins out as you rise above the surface and cools considerably; about 30 miles up you hit the sweet spot for human habitation: Mediterranean temperatures and sea-level barometric pressure. If ever there were a place to build a floating city, this would be it.

Believe it or not, a floating city might be a feasible project. Scientist and science fiction author Geoffrey Landis presented a paper called "Colonizing Venus" [PDF] at the Conference on Human Space Exploration, Space Technology & Applications International Forum in Albuquerque, New Mexico back in 2003. Breathable air floats in Venus's soupy carbon dioxide atmosphere, which means on Venus, a blimp could use air as its lifting gas, the way terrestrial blimps use helium to float in our much thinner atmosphere. ...

One of the biggest problems with a lunar or Martian colony is that an astronaut’s bones and muscles deteriorate in low gravity. No one knows yet how much gravity a human needs to prevent deterioration, but Venus's gravity is the closest to Earth's, at about 9/10ths. Mars only has a third of the gravity that the Earth does, while the moon has a mere sixth.

Atmospheric pressure is also crucial. Think of the difference between jabbing a car tire and letting air out of a half-inflated balloon. Gases seek equilibrium. Since there's barely any atmosphere on the moon or Mars, a rip in the hull of an enclosed human habitat would suck oxygen out at tremendous force. Thirty miles above Venus, it would merely seep out. This also means a Venutian cloud colony wouldn't need as much reinforcement. Venus has other boons, too. Its rich atmosphere blocks radioactivity and could be mined for useful materials. And with a gentle temperature, far less energy would have to be spent on heating or cooling the colony.
--James McGirk, Citylab, on a new planet to love. HT: Chris Blattman