65
$\begingroup$

In many science fictions we see planets which are designated by a particular terrain type. For example, Dagobah is a swamp planet, Tatooine is a desert planet, and Kamino is an ocean world.

However, Earth has a much more varied and interesting geography with all kinds of environments stretching from oceans to desert and everything in between.

How realistic is it to portray a planet as a "Jungle Planet"? Is this simply a storytelling technique to help viewers/readers identify the location from its distinctive appearance?

$\endgroup$
  • 13
    $\begingroup$ That reminds me of a Stargate episode where the SG team lands in the polar region of earth through a second, not previously known star gate on earth. The first comment after arriving: "We're on an ice planet!" OTOH, the earth could very well be characterized as a water planet, even though it's not <em>only</em> water, because most of its surface is oceans. $\endgroup$ – celtschk Sep 17 '14 at 14:08
  • 1
    $\begingroup$ Isn't earth basically an ocean planet just at the moment a lot of the ocean is in ice sheets? $\endgroup$ – Toby Allen Apr 17 '15 at 22:31
  • 1
    $\begingroup$ @TobyAllen - no, if all the ice melted, sea level would only rise about 70m, leaving still a lot of land. $\endgroup$ – Mikey Dec 15 '15 at 22:18
  • 2
    $\begingroup$ 70+% water seems a pretty good definition of "ocean planet". $\endgroup$ – RonJohn May 17 '17 at 0:23
  • 1
    $\begingroup$ A cold enough water planet will be an ice planet. A hot enough rocky planet would be a desert planet. "Typed" planets between the two would require some ... interesting ... geographical tricks to create a relatively uniform planet surface. Reminding me of Douglas Adam's description of the planet used as the headquarters for the company that publishes Hitchhiker's Guide to the Galaxy as being basically completely coastal Californian and perpetually Friday afternoon due to a geotemporal anomaly. $\endgroup$ – Isaac Kotlicky Jul 12 '17 at 12:34
49
$\begingroup$

Planets which have something that we might consider to all be a single climate given the way we classify things based on earth is entirely plausible, for certain climates at least.

Mars easily qualifies as a desert over its entire surface. There is climate variation, but all of it is something we would call "desert".

Similarly, you could have more water to the point it covers everything and the entire planet would be ocean (which isn't exactly a climate in and of itself). But oceans can have varying climates. Variations based on depth, insolation, currents, etc. The intertropical convergence zone would likely be a massive band band of thunderstorms. Then you'd have calm doldrums, and then utterly mid latitudes where massive hurricanes sweep across periodically.

A global swamp or jungle though doesn't seem workable. A global wetland would need an almost perfectly smooth planet where everything was in an absolutely perfect balance. "Jungle" is fairly specific and tied to the specific nature of life on the planet. Both global jungle and global wetland have the severe problem of where you maintain a reservoir of water to generate the rain with oceans.

Making a single climate planet habitable is also problematic. Without phytoplankton and forests, a desert planet isn't going to have an oxygen rich atmosphere, unless you do something strange like the Sand Worms of Arrakis in Dune which produce ridiculous amounts of oxygen. Then again they are generally just ridiculous creatures so you might as well just declare that where the oxygen comes from is irrelevant to the story. One might say that Arrakis isn't functionally a desert for its native life because lack of water is irrelevant to them.

What makes a place a "functional desert" is extreme scarcity of a resource life needs, but which can be gathered, retained, and re-used. Most likely a solvent or other medium within which biological chemistry occurs. It's improbably that life would originate on a planet which is entirely functionally desert for that life.

$\endgroup$
  • 1
    $\begingroup$ Well, I was writing an answer, but you've basically covered everything I was going to say. +1 to you, good sir. $\endgroup$ – Jerenda Sep 16 '14 at 21:05
  • $\begingroup$ Mars would probably be classified as tundra rather than desert. $\endgroup$ – Chad Sep 16 '14 at 23:14
  • 5
    $\begingroup$ @Chad they are not mutually exclusive. $\endgroup$ – smithkm Sep 16 '14 at 23:27
  • 2
    $\begingroup$ Arrakis is not actually lacking water, it's just that it's bound by the sand worms (at least that's what i understood) $\endgroup$ – kutschkem Oct 22 '14 at 14:40
  • 2
    $\begingroup$ I think a global swamp planet is totally plausible -- what is needed is a thick enough atmosphere to homogenize the surface temperature. Since this thick atmosphere would have a corresponding greenhouse effect, this imposes constraints on the planet's orbit (it can't be too close to the Sun). Consider an extreme case: a free-floating planet with no star. Life could exist there as long as it has a thick hydrogen atmosphere (see aeon.co/essays/…). But there would be no reason for any temperature differences across the surface. $\endgroup$ – Sean Raymond Jun 29 '16 at 14:12
13
$\begingroup$

I'm going to take one of your examples here: the desert planet. Is that realistic and plausible?

It turns out that it is realistic. Wikipedia describes a desert thusly:

A desert is a barren area of land where little precipitation occurs and consequently living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation.
...
Deserts are formed by weathering processes as large variations in temperature between day and night put strains on the rocks which consequently break in pieces.

Desert climate is described as:

Desert climate (in the Köppen climate classification BWh and BWk, sometimes also BWn), also known as an arid climate, is a climate that does not meet the criteria to be classified as a polar climate, and in which precipitation is too low to sustain any vegetation at all, or at most a very scanty shrub.

Polar climate is defined primarily by the lack of warm summers:

Every month in a polar climate has an average temperature of less than 10 °C (50 °F).

It turns out that the above description of desert climate sounds like a pretty decent description of Mars' climate. Mars' large orbital difference between perihelion and aphelion creates constant thermal stress, which the thin atmosphere does little to reduce; temperature swings of nearly 200 Kelvin are seen between the extremes on the surface and between summer and winter, whereas summer daytime temperatures of around 35°C have been measured. Mars also shows a fairly large difference between daytime and nighttime temperatures, which is a property typical of desert areas, but I cannot seem to find any specific figures at the moment.

$\endgroup$
11
$\begingroup$

I think you're indirectly asking about scope. Any world deals with levels of encapsulation. The lower down the levels the bigger the frequency. As with anything the higher the frequency of something the more time it takes to develop it so therefore the more likely a person is to create quick methods of applying detail to it.

Lucas vs. Tolkien

The model for each franchise is identical, the scope is not. Lucas' top-level encapsulation is a universe, Tolkien chose a planet. Lucas' universe has many planets, Tolkien's planet has many regions. Lucas' universe has swamp planets, Tolkien's planet has swamp regions.

It all comes down to how many examples of a specific level of encapsulation you have. If you're doing a universe like Lucas, you most likely don't have the time to describe all of your planets to the same level of detail as Tolkien did with Arda.

$\endgroup$
  • 3
    $\begingroup$ It is not an answer to the question "Are [these] realistic?", but it is a good answer about worldbuilding/storytelling itslef, so upvoting it. $\endgroup$ – Envite Sep 23 '14 at 18:02
  • $\begingroup$ I actually think that this is the best answer for the question, even if this is not what people would expect as an answer. $\endgroup$ – Renan Jun 29 '16 at 14:48
6
$\begingroup$

A desert planet is not unrealistic at all - plenty of them exist. A desert planet able to support life would presumably be possible, if given the right kind of atmosphere. A completely-ocean planet would not be too implausible either: it would be just like earth, but with much deeper oceans. An entirely-jungle planet, however, may be difficult, as it would need to have a roughly-consistent temperature. With a bit of modifications, there could be fast-growing plants that can survive in any climate (especially if the planet's axis is not tilted so that the amount of sunlight each plant gets is constant). You could certainly have a planet completely covered in plants, but it seems unrealistic for all the plants to be tropical (which may be part of the definition of a jungle).

$\endgroup$
1
$\begingroup$

I think it is totally plausible for there to be planets with a single kind of terrain. For this to happen, the whole surface of the planet must be at roughly the same temperature (unless you're talking about a desert planet and allow different types of desert). This doesn't happen on Earth: the poles are much colder than the equator. The situation is even worse on Mars, in terms of the temperature differential between the poles and equator. On Venus the entire surface is indeed at about the same temperature. This is because Venus' thick atmosphere and strong winds are so efficient at redistributing heat across the planet's entire surface that any temperature differences are smoothed out.

Like Venus, I think a planet with habitable conditions could have a relatively uniform surface temperature. With a thick enough atmosphere the surface temperature would be relatively homogeneous (in detail, this also depends on things like the atmospheric composition and spin rate). I don't see why you couldn't have a planet like Dagobah, with a thick atmosphere that maintains jungle-like temperatures across the whole planet. Or a water world that is a global ocean with similar temperatures.

Since a thick atmosphere often has a significant greenhouse effect, a planet with a uniform surface temperature would likely be relatively far from its star, in the outer parts of the habitable zone. In the most extreme case you could imagine a free-floating planet with no star. It's plausible that such planets could have life, either under a thick hydrogen atmosphere or in an ocean under a thick layer of ice (see here: https://aeon.co/essays/could-we-make-our-home-on-a-rogue-planet-without-a-sun or here: https://planetplanet.net/2015/06/04/real-life-sci-fi-world-8-the-free-floating-earth/)

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.