Monday, January 28, 2013

Gas Giant Planets--open for settlement?

When looking for new homes for the human race, people generally think of worlds like Earth, that is, planets with a solid crust and liquid water oceans, places where plants might grow and animals might be available to eat. Sometimes people expand this to include lifeless moons or perhaps moons or worlds with trapped water, like Ganymede or Mars. But why shouldn’t we consider living on worlds not like Earth at all? Why not gas giants, like Saturn, Uranus, and Neptune?

Clearly a planet just like Earth would be a better place to live if your level of technology were in, say, the Stone Age. But with a higher level of technology—hey, even with twentieth century technology—the challenges of a world radically different from Earth, like a gas giant, don’t really pose a problem. Can’t breathe the air? Solve that by living in controlled atmosphere habitats. No solid surface to set down on? Float your giant living habitat on balloons. No plants or animals to eat? Grow or raise your own in your hydroponic gardens/animal pens.

If you ask the question, “What does a planet really need to offer for a human being to survive?” technology makes the number of specific things required less than they otherwise would be. Perhaps the main thing a planet needs to offer is resources—energy sources and building materials. It might seem at first glance a gas giant would not offer enough of what humans really need, since we build in metals and glass and the atmosphere of a gas giant is mostly light gasses like hydrogen, helium, methane, and carbon dioxide.

But if you build your habitats out of carbon-composite materials, you have all the carbon you could ever need in the atmospheric methane and CO2. You just need to extract it. A byproduct would be oxygen and hydrogen, or water if you choose—though the atmospheres of most gas giants have plenty of water vapor anyway.

Orbital astronaut experience has shown that gravity is essential for humans to live normally—and guess what? In the atmosphere of the three smaller gas giants in our Solar System, the amount of gravity you’d experience is roughly equal to that of Earth (Jupiter, though, would be far too much gravity for humans).

You could adjust the height and latitude of the craft to match a zone where the pressure and temperature is similar to that of Earth’s atmosphere. The magnetic fields and atmospheres of these worlds would do you the favor of protecting your settlers from dangerous solar and cosmic radiation. And you could add to your habitat from available carbon on an unlimited basis, provided you had the energy to process it—and plenty of energy would be available by harnessing wind power (and plenty of deuterium would be available for hydrogen fusion).

An advantage to settling a gas giant would be that it would take a very, very long time to run out of available room, since these atmospheres are massively huge by Earth standards. Plus, there seems to be a great many gas giants orbiting not just our own star, but others. Note a similar technique could be used to settle the atmosphere of a hot world with a dense atmosphere like Venus. Perhaps the floating habitations there could fly above the clouds, not unlike the Cloud City of Star Wars fame…

A disadvantage to a gas giant settlement would be entering and exiting its atmosphere. Yes, the density is of these worlds is lower, reducing the sensation of gravity if you were in their atmosphere—but they’re still very massive. There’s a lot of gravity to fight in coming and going, not to mention wind resistance. It would be much harder for a spacecraft to exit Saturn for a trip back to Earth than, say, Mars.

Another problem comes from the massive storms whipped up by the atmospheres of these worlds. The storm problem might be insurmountable, in fact. Very fast winds aren’t so much a problem—it’s when the winds change speed and direction so rapidly they would break a human habitat in half—or at least splatter the humans inside against the walls like jelly...

Still, certain gas giants could have layers of great stability, where the atmosphere maintains consistent conditions over essentially indefinite time…that’s something you’d want to discover before establishing the settlement, of course. In general, though, it seems the further away from the sun (or for extrasolar worlds, its star) a world is, the more stable and consistent its atmosphere. So, it seems that Neptune is more stable than Saturn, perhaps stable enough to settle without problem…which is interesting and ironic in that like Earth, Neptune is a blue world…

What if aliens had already settled gas giants and had discovered means to create areas in which the storms are less dangerous? Saturn has a permanent storm pattern around its south pole shaped like a giant hexagon. What if this area were a place of massive alien settlement? Or what if Jupiter’s Great Red Spot, which human scientists see as a giant storm, is a deliberate attempt to create a predicable storm—where the winds change in a regular way, supporting hundreds of millions of alien habitations floating on giant balloons in the midst of the Jovian atmosphere...they'd actually be a lot harder to detect than you might think...



  1. Please note that for this post I categorized Uranus and Neptune as "gas giants." Since the 90's they've been considered "ice giants," but the principle, which I applied even to Venus, remains the same...

  2. Both Geoffrey Landis and Robert Forward have written stories about humans floating in balloons at a certain atmospheric level. Landis has stories set on Venus, Forward did one on Saturn

  3. Clearly I haven't read enough of Geoffrey Landis and Robert Forward. Thanks for the input!