I just rolled up the most horrendous "habitable" planet ever.

[acrosome]

Originally Posted by The Colonel

Reminds me of that planet from the old 2300AD supplement "Kafer Dawn" - tidally locked with the settlements on a thin equatorial belt, vicious tidal activity and a non-compatible biota.

Aurora! Yes, excellent setting.

And of all things TSR's Star Frontiers had a world that completely froze at "night", with herd animals that migrated around the entire world to stay in daylight. I can't recall the name, though... Alcazzar? And Mutiny on the Eleanor Moraes was almost adequate.

[jason taylor]

Garden? I presume it has odd plants?

[Johnny1A.2]

Originally Posted by Ulzgoroth

Without technological support is asking a lot..

Yeah, but I use it for a reason.

In principle, a viable human breeding population could endure indefinitely on Earth without any tools or equipment, just as other animals do. Fantastically difficult, yes, but possible. Allow simple TL0 tools and it becomes a very viable, in pure species survival terms. Earth is the only planet in the Solar System of which this is true.

If technological support is allowed, you have to draw a line to make the definition of 'habitable' mean anything. For a human population with access to high end (only modestly ahead of our own) space-flight level technology and a viable economic/industrial base, most planets are 'habitable'. For such a society, Mercury, Luna, Mars, the major asteroids, many of the big satellites of the gas giants, even the KBO worlds, are all 'habitable', in the sense that viable breeding populations could endure indefinitely on them. For slightly more advanced societies, even worlds like Venus and Io are 'habitable'. Advance the tech a bit more and the gas giants become 'habitable'.

Whether a world is classified as habitable or not depends on the metric.

[Ulzgoroth]

Originally Posted by Johnny1A.2

Yeah, but I use it for a reason.

In principle, a viable human breeding population could endure indefinitely on Earth without any tools or equipment, just as other animals do. Fantastically difficult, yes, but possible. Allow simple TL0 tools and it becomes a very viable, in pure species survival terms. Earth is the only planet in the Solar System of which this is true.

If technological support is allowed, you have to draw a line to make the definition of 'habitable' mean anything. For a human population with access to high end (only modestly ahead of our own) space-flight level technology and a viable economic/industrial base, most planets are 'habitable'. For such a society, Mercury, Luna, Mars, the major asteroids, many of the big satellites of the gas giants, even the KBO worlds, are all 'habitable', in the sense that viable breeding populations could endure indefinitely on them. For slightly more advanced societies, even worlds like Venus and Io are 'habitable'. Advance the tech a bit more and the gas giants become 'habitable'.

Whether a world is classified as habitable or not depends on the metric.

Defining a boolean trait which only ever is false seems kind of pointless though.

[doctorevilbrain]

That is sooo true!

[Lancewholelot]

Originally Posted by Johnny1A.2

For a human population with access to high end (only modestly ahead of our own) space-flight level technology and a viable economic/industrial base, most planets are 'habitable'. For such a society, Mercury, Luna, Mars, the major asteroids, many of the big satellites of the gas giants, even the KBO worlds, are all 'habitable', in the sense that viable breeding populations could endure indefinitely on them. For slightly more advanced societies, even worlds like Venus and Io are 'habitable'. Advance the tech a bit more and the gas giants become 'habitable'.

That is speculative and still the stuff of science fiction. No human has ever been born off the Earth's surface. The long term effects of low to no gravity on viable human development are unknown.

[J. Edward Tremlett]

Trying to imagine how life could evolve there. It'd be constantly undergoing boom and burn cycles and have to find a way to cocoon.

[dcarson]

One think that habitable is can a average human produce enough wealth to produce the tech needed to keep an average human alive. We could build a Moon colony today but it would have to be subsidized.

[Johnny1A.2]

Originally Posted by Lancewholelot

That is speculative and still the stuff of science fiction. No human has ever been born off the Earth's surface. The long term effects of low to no gravity on viable human development are unknown.

Fair point. But even that is correctible by an advanced/large enough techbase/economy. Centrifuges can be built, for ex. It might never be practical, but it's possible in principle.

Which is my point, the boundary of 'habitability' depends on the technology and economy available.

[Johnny1A.2]

Originally Posted by Ulzgoroth

Defining a boolean trait which only ever is false seems kind of pointless though.

It isn't only ever false, though. Earth exists. It's the one definite True we know about, but it does exist.