Why can’t these things be done in Star Wars?

[Polydamas]

Originally Posted by Irish Wolf

Except that, plainly, both Tatooine and Hoth have free oxygen. Same for Coruscant, which is supposed to be entirely covered by city according to The Lore.

The only reasonable conclusion is that these aren't actually single-biome planets, but rather worlds where the growing bits are smaller than on Earth.

I would be very careful about using post-1800 science to conclude anything about the Star Wars universe. Can you think of anything in the 3 or 9 core films which is there because someone used principles of natural philosophy which Lucretius or Albertus Magnus would not have recognized? So they have 'lasers' which work like guns, and 'spaceships' which move like birds and fall to the earth when they lose their motive force.

[whswhs]

Originally Posted by Polydamas

I would be very careful about using post-1800 science to conclude anything about the Star Wars universe.

At least if we're talking about oxygen 1800 may be too early a date. I don't think it was clearly recognized until James Lovelock's work in the 1970s or so that it was explicitly recognized that oxygen atmospheres are chemically unstable and have to be constantly replenished by photosynthetic energy capture. Science fiction in the 1940s and 1950s seems just to treat "oxygen atmosphere" as an option on a list.

[Flyndaran]

Wasn't Luke a moisture farmer? That would mean that if there's enough water vapor to actively gather, it had to have been coming from somewhere.
Numerous but small salt seas wouldn't change the desert planet status even in a more realistic setting, IMO.

[Agemegos]

I doubt that the writers put any more thought into where the moisture on Tatooine came from than they did into where the oxygen came from. Star Wars is just not the kind of work from which it is sensible to ask that much detail in the background and attention to science.

[whswhs]

Originally Posted by Agemegos

I doubt that the writers put any more thought into where the moisture on Tatooine came from than they did into where the oxygen came from. Star Wars is just not the kind of work from which it is sensible to ask that much detail in the background and attention to science.

Remember the classic example of Trantor, capital of Isaac Asimov's Galactic Empire. We are told that it had an enormous population, maybe up around a trillion, that it was all one huge city, and that food was shipped in from many surrounding solar systems in vast fleets. Of course this was all a reference to ancient Rome importing wheat from the Nile Valley and Sicily! But Rome was in the same atmosphere as the rest of the Earth and benefited from gaseous diffusion to make up its oxygen deficit. I remember reading one satiric short piece that envisioned the huge air fleets carrying oxygen to Trantor. . . .

And this was from a Ph.D. in biochemistry! Really back in the day everyone, not just handwavy movie makers, took oxygen/nitrogen atmospheres for granted. I think it was the discovery of how hostile Mars and Venus were during the 1960s that started people like Lovelock thinking things through.

(There was a storyline in Swamp Thing that contrasted the benevolent Green with the malignant Gray of fungi. And the first thought I had was, "Yes, when photosynthetic organisms evolved they started flooding the atmosphere with a toxic gas that exterminated most of the biosphere that existed then!" But of course now we've evolved to depend on it.)

[Anders]

Originally Posted by whswhs

Remember the classic example of Trantor, capital of Isaac Asimov's Galactic Empire. We are told that it had an enormous population, maybe up around a trillion, that it was all one huge city, and that food was shipped in from many surrounding solar systems in vast fleets. Of course this was all a reference to ancient Rome importing wheat from the Nile Valley and Sicily! But Rome was in the same atmosphere as the rest of the Earth and benefited from gaseous diffusion to make up its oxygen deficit. I remember reading one satiric short piece that envisioned the huge air fleets carrying oxygen to Trantor. . . .

David Morgan-Mar has a number of comics about the improbability of Coruscant, which is based on Trantor. Thermodynamics predict that the planet would turn into a fireball very quickly.

[Polydamas]

Originally Posted by whswhs

At least if we're talking about oxygen 1800 may be too early a date. I don't think it was clearly recognized until James Lovelock's work in the 1970s or so that it was explicitly recognized that oxygen atmospheres are chemically unstable and have to be constantly replenished by photosynthetic energy capture. Science fiction in the 1940s and 1950s seems just to treat "oxygen atmosphere" as an option on a list.

Fair enough. And Han Solo does mention "light speed" which suggests that George Lucas was aware of relativity in a series which is based around faster than light travel (fans have decided that "light speed" is a translation for a technical term related to hyperdrive).

Probably its reasonable to assume the worldview of a high-school graduate in the 1940s, although if Lucas had felt inspired he might well have had human-alien hybrids (in Edgar Rice Burroughs but not 1890s biology). So blasters and turbolasers are not so different than the heat rays in "Red Nails" (1936) and work like guns in a WW II film. Its a mix of the cool things in pulp magazines, WW II films, and Akira Kurosawa.

[cptbutton]

Originally Posted by whswhs

I remember reading one satiric short piece that envisioned the huge air fleets carrying oxygen to Trantor. . . .

There is a bit on this in Harry Harrison's Bill, The Galactic Hero.

[Agemegos]

Originally Posted by whswhs

Remember the classic example of Trantor, capital of Isaac Asimov's Galactic Empire. We are told that it had an enormous population, maybe up around a trillion, that it was all one huge city, and that food was shipped in from many surrounding solar systems in vast fleets.

…

And this was from a Ph.D. in biochemistry!

Right! The oxygen and moisture in the air on Tatooine and Hoth (and Arrakis), and the urbanisation of Coruscant (and Trantor) are impossibilities but they are not errors. They are genre conventions, no better to be "corrected" than FTL travel.

Really back in the day everyone, not just handwavy movie makers, took oxygen/nitrogen atmospheres for granted.

And they thus created a genre and its conventions. It's a fun genre. Crushing its conventions with the conventions of a different genre is not the sport for me. (Just don't try to convince me that Star Trek and Traveller are hard science fiction.)

[whswhs]

Originally Posted by Agemegos

Right! The oxygen and moisture in the air on Tatooine and Hoth (and Arrakis), and the urbanisation of Coruscant (and Trantor) are impossibilities but they are not errors. They are genre conventions, no better to be "corrected" than FTL travel.

I don't think that Frank Herbert thought of it as a convention, and I'm fairly sure that Isaac Asimov and John W. Campbell did not. I think the hard science of the era had not figured out the harsh realities of planetary atmospheric chemistry fully, and what they did know had not gotten as far as the Astounding stable of writers, not even the ones with a scientific education. It's like E.E. Smith giving us planets with chlorine atmospheres, which goes flat against the cosmic abundance of the elements. Of course for writers who do them now they're a genre convention.

Certainly past writers have often disregarded scientific issues, though. I've read a passage from one of H.G. Wells's letters where he discussed handwaving the issue of "how does he see?" to write The Invisible Man.