The "Star Wars" Worlds: More Science Than Fiction?

Stefan Lovgren
for National Geographic News
June 3, 2005
Everyone knows the Star Wars galaxy is located "far, far away." But how realistic are the alien worlds (see pictures) described in the science fiction saga?

To find out, National Geographic News checked in with two experts on everything extraterrestrial: Bruce Betts, a planetary scientist at the Planetary Society in Pasadena, California, and Seth Shostak, a senior astronomer at the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, California.

National Geographic News: So how believable is the Star Wars galaxy?

Betts: They [the filmmakers] have set up a fictional structure that is so far outside our reality that they can get away with an awful lot. What they have in their favor is that they use an entire galaxy.

A galaxy has, say, a hundred billion stars and maybe that many planets. If they've picked out the worlds where life has evolved or where life can exist, it's hard to argue there couldn't be 20 [such planets] in a galaxy of a hundred billion planets.

Shostak: What we might complain about is that so many of the galactic sentients [intelligent life-forms] seem determined to live on planets. Truly advanced life is likely to build its own habitats, and escape the limited area and resources of a planet. In Star Wars, it seems that only Monsieur Vader has figured this out, building his own artificial habitat, appealingly monikered the Death Star, even though it's not a star at all. But "Death Space Habitat" doesn't have as nice a ring to it.

NG News: Should we assume the major characters are human?

Betts: The literature, I think, refers to them as humans sometime. Although we're in a galaxy far, far away, I still make the assumption that these people breathe oxygen. That makes things a little tricky.

No matter what atmosphere they drop into, they're able to breathe. It seems odd that the Wookiee planet, for example, would have the right amount of oxygen for people who grew up on Tatooine, when we know that even going to a higher altitude on Earth becomes a problem in terms of oxygen. But now I'm just nitpicking.

NG News: By all means, nit-pick.

Shostak: Maintaining a cohesive empire, or even a republic, over a decent swath of any galaxy would be impossible without faster-than-light travel, of course. You need FTL travel, which Star Wars has, to even contemplate such far-flung organizations.

Even so, it all seems unlikely, because the various inhabitants, many of which are biological, will have evolved at different times. Consequently, the top species will be many millennia ahead of the number two species, in terms of evolution, and millions and billions of years ahead of your average intelligent species. They won't want to share drinks with them in a Mos Eisley cantina.

NG News: Or have Wookiees as co-pilots.

Shostak: Right. Either all members of the Empire or Republic will be the same species, or there won't be an Empire or Republic. In addition to this, there are "droids" all over the place—synthetic intelligence. Since artificial intelligence can evolve much, much faster than biological smarts, why do the biological beings have any place whatsoever in the dramas of the Empire? They should have become obsolete very quickly.

NG News: Let's talk about some of the specific planets we encounter in the Star Wars movies. What about Naboo, for example, the home planet of Queen Amidala? It's an idyllic world (see picture) populated by peaceful humans and an indigenous species of intelligent amphibians, the Gungans.

Betts: It seems like the most Earthlike world. It's certainly not hard to imagine that it could have evolved underwater species. But from the wicked ways of our own world, it seems unlikely that two highly intelligent species would be able to live together peacefully.

Shostak: We have rather few examples of two or more intelligent species simultaneously sharing a planet, but it has happened. The Neanderthals coexisted with Homo sapiens for millennia. So maybe it's possible to share, as long as neither species has the technology to obliterate, enslave, or merely cook and eat each other.

There is the objection that an underwater species might have difficulties fostering technology. Smelting metals, or even developing radio or astronomy, are challenging, to put it modestly, in a watery environment.

NG News: How about Coruscant? Situated in the heart of the galaxy, it (see picture) is completely covered by one massive city and is the seat of government for the Galactic Republic and later the Empire.

Shostak: In general, you don't want to be quite in the "heart" of any large galaxy, as that's almost invariably the site of a massive black hole, and an active nucleus that will fill nearby space with corrosive radiation guaranteed to ruin your whole day.

So it's better to be in the "outer aorta" of the galaxy, far enough from the nucleus to avoid the radiation but close enough to take advantage of the fact that the density of stars there will be a million times higher than in the galaxy's outer neighborhoods. Not only does that give you more places to build condos but more raw material and more energy, all of which would be useful in sustaining the high-voltage, urban lifestyle of Coruscant.

NG News: Bespin is an immense gas giant (see picture) surrounded by a number of moons. It contains a band of habitable atmosphere among the clouds. This is where Cloud City is located, a mining colony set up to extract valuable Tibanna gas.

Betts: This is the one planet I have the most trouble buying. There are, of course, examples of gas giants surrounded by moons. We have that in our own solar system. But a "band of habitable atmosphere"?

Assuming we take that to mean temperature and oxygen without there being anything noxious or dangerous, that's certainly beyond our current expectations or measurements. Making this particularly tricky, molecular oxygen that we breathe does not occur easily in a planetary environment. Almost all the oxygen on Earth comes from life.

Shostak: I don't know what Tibanna gas might be. Gas-giant planets seem to be swathed in ammonia, methane, and other vapors that, frankly, are neither rare nor particularly valuable. They are useful for cleaning the bathroom or cooking dinner, of course.

NG News: What about Dagobah, the forgotten world (see picture) where Luke Skywalker trains with Yoda in The Empire Strikes Back? Its huge lagoons and mist-shrouded swamps are teeming with life.

Shostak: This swamp planet is really only a [stand-in] for Earth during the Pennsylvanian period, when swamps were common, vegetation was lush, and coal was being formed. It's our planet as it was 300 million years ago, before things got a bit colder.

Betts: One of the things I find less realistic in movies is that the planets tend to be very uniform in climate. With Mars and Earth you tend to have lots of variation across the planet, but planets in movies are characteristic of one climate area. So you have the jungle planet, the ice planet, and so on. But the most amazing thing about Dagobah, of course, is that Luke just happened to fall within hundreds of feet of Yoda. I suppose we chalk that up to the Force.

NG News: What do you think of Hoth, a world (see picture) of snow and ice? Although small meteorites from a nearby asteroid field constantly pelt its surface, the planet has developed several indigenous life-forms, including the tauntaun creature.

Betts: A nearby asteroid field? Hmm, it would be tricky to keep it in place. … Perhaps it's early in that solar system's development and the planet, like early Earth, is under bombardment. But then it would be odd to have very advanced life evolved there.

NG News: OK, so how about the big one, Tatooine (see picture), Anakin and Luke Skywalker's home planet? It's pretty dusty.

Betts: Is the whole world really arid? You can develop a really arid world, like Mars, but once it is mostly arid, it is hard to keep any liquid water. Liquid water is one of three things needed for life on Earth, so it's probably not a terrible assumption to make that it's needed for life elsewhere too.

Even Mars has had periodic outflows of water, but we're not sure how long it persisted as a liquid. But who knows what life looks like on other planets? Biologists can't even agree on what life is on our own planet.

NG News: One planet that looks even less pleasant is Mustafar (see picture), the volcanic backdrop of the final duel between Obi-Wan Kenobi and Anakin Skywalker.

Shostak: This is a world that looks like Hawai'i Volcano[es] National Park—everywhere. How could you have a planet that's covered in hot, soft rock? Only two possibilities: One, it's a newly formed world, in which case, the mining operation here—mining lava?—is in trouble, because there will be lots of incoming asteroids that would routinely wipe out your industrial infrastructure.

Or, two, it's in a highly elliptical orbit around either a big planet or its home star so that, like Jupiter's moon Io, it's constantly subjected to the push and pull of a changing gravitational tug. Kneaded like bread dough, such a world would become very hot and might quite possibly have the blast furnace countenance that Mustafar wears. So this is not at all impossible.

Betts: But to make this compatible with contemporary life is a challenge. It's really tricky to imagine that you would have oxygen here. But, hey, they're Jedi—they can probably control their breath.

Shostak: The most amazing thing is, Obi-Wan and Anakin duke it out here amongst rivers of molten lava and they don't even break a sweat.

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