Classic SF Featuring Planets With Very Long or Very Short Days

Earth is blessed with a day neither of extraordinary length nor of extreme brevity. Currently it is about twenty-four hours long. A quick glance at planets like Mercury and Venus shows us that worlds can have days much longer than Earth’s; bodies like Haumea suggest that days could be much shorter.

SF authors have notice this and written books about planets/planetesimals with different day lengths. Consider these five vintage works.


Mission of Gravity by Hal Clement (1953)

61 Cygni’s world Mesklin is sixteen times more massive than Jupiter. A day less than twenty minutes long means that the gravity at the equator is a measly three gravities. Thus, human starfarer Charles Lackland is able to briefly set down near the equator, where he is subjected to extreme discomfort (rather than immediate death). Too bad for Lackland that the object of his quest, a lost probe, is near one of Mesklin’s

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5 Science Fiction Books Featuring Floating Habitats

Venus tourism poster, created for by NASA/Jet Propulsion Laboratory-Caltech (Creative Strategy: Dan Goods, David Delgado; Illustrator: Jessie Kawata)

Venus is so inconsiderate. It presents itself as a sister world, one that would seem at first glance to be very Earth-like, but… on closer examination it’s utterly hostile to life as we know it. Surface conditions would be extremely challenging for terrestrial life, what with the toxic atmosphere, crushing pressures, and blast-furnace-like temperatures.

That’s at the surface, however. Just fifty kilometers above the surface, there is a region with terrestrial pressures and temperatures, a veritable garden of Eden where an unprotected human would not be almost immediately incinerated but instead would expire painfully (in just a few minutes) due to the lack of free oxygen and the prevalence of toxic gases.

Nonetheless, visionaries like Geoffrey Landis have pointed out the possibility of floating cities high in the atmosphere, cities that would

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Five SF Works Featuring Dyson Shells (and Not Dyson Swarms)

The basic concept of the is straightforward: rather than squander stellar output by permitting it to radiate into space, one can surround the star with a shell to intercept light, thus permitting the energy to be put to use. From the viewpoint of the star system’s inhabitants, this would be a useful source of energy (although any civilization able to turn its planets into a Dyson Sphere would be at most twenty years from commercial controlled fusion).

There are at least two kinds of Dyson Sphere. The first—the one Dyson intended—is made up of a myriad of independently orbiting objects. While this presents an interesting traffic control challenge, the Dyson Swarm has the advantage that not only can it be built incrementally over a very long period, but the components are gravitationally coupled to the star in question.

The second option is a solid shell with the star in the

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