Tidal Moon

Last updated
"Tidal Moon"
Author Stanley G. Weinbaum and Helen Weinbaum
CountryUnited States
Genre(s) Science fiction
Published in Thrilling Wonder Stories
Publication type Periodical
Publisher Thrilling Publications
Media typePrint (Magazine)
Publication dateDecember 1938

"Tidal Moon" is a science fiction short story by American writer Stanley G. Weinbaum and Helen Weinbaum that first appeared in the December 1938 issue of Thrilling Wonder Stories and was reprinted in the collection Interplanetary Odysseys (2006). Sam Moskowitz stated that Stanley G. Weinbaum completed only a page and a half of the story before his death and that his sister Helen Weinbaum completed the story on her own. [1] "Tidal Moon" is the only story by Weinbaum to take place on Ganymede.

Science fiction Genre of speculative fiction

Science fiction is a genre of speculative fiction that has been called the "literature of ideas". It typically deals with imaginative and futuristic concepts such as advanced science and technology, time travel, parallel universes, fictional worlds, space exploration, and extraterrestrial life. It often explores the potential consequences of scientific innovations.

Short story work of literature, usually written in narrative prose

A short story is a piece of prose fiction that typically can be read in one sitting and focuses on a self-contained incident or series of linked incidents, with the intent of evoking a "single effect" or mood, however there are many exceptions to this.

Stanley G. Weinbaum US writer

Stanley Grauman Weinbaum was an American science fiction writer. His first story, "A Martian Odyssey", was published to great acclaim in July 1934, but he died from lung cancer less than a year and a half later.


Weinbaum's Ganymede

In Weinbaum's Solar System, Jupiter radiates enough heat to create Earthlike environments on the Galilean moons. Ganymede, the third Galilean satellite, has a subarctic climate, large bodies of water, and a six-month rotation period. Due to Jupiter's tidal pull, every spot on Ganymede's surface is inundated with water every three months except a small area of the south pole where the human settlement of Hydropole is located. The Ganymedian natives, the Nympus, grow a mosslike plant called cree which is ordinarily red, but which turns blue when exposed to the ammonia in Ganymede's atmosphere. The blue moss is collected by human traders in the employ of Cree, Inc. who travel among the native villages on an aquatic riding animal called a hipp (short for Hippocampus catamiti); it is then shipped to Earth to produce crephine, a combined anaesthetic and medicine. Other Ganymedian life-forms include the whale-like Gamma Rorqual, the tentacled land leet, and the four-winged Blanket Bat.

Solar System Planetary system of the Sun

The Solar System is the gravitationally bound system of the Sun and the objects that orbit it, either directly or indirectly. Of the objects that orbit the Sun directly, the largest are the eight planets, with the remainder being smaller objects, such as the five dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly—the moons—two are larger than the smallest planet, Mercury.

Jupiter Fifth planet from the Sun in the Solar System

Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass one-thousandth that of the Sun, but two-and-a-half times that of all the other planets in the Solar System combined. Jupiter has been known to astronomers since antiquity. It is named after the Roman god Jupiter. When viewed from Earth, Jupiter can be bright enough for its reflected light to cast shadows, and is on average the third-brightest natural object in the night sky after the Moon and Venus.

Galilean moons four moons of Jupiter

The Galilean moons are the four largest moons of Jupiter—Io, Europa, Ganymede, and Callisto. They were first seen by Galileo Galilei in December 1609 or January 1610, and recognized by him as satellites of Jupiter in March 1610. They were the first objects found to orbit another planet.

Plot summary

Ben Amherst is a cree collector on Ganymede in the year 2083. Although he normally operates alone, he finds himself accompanied on one of his rounds by a tourist from Earth named Kirt Scaler. Scaler plans to travel with Amherst to the village of Aquia, then remain there for two months while Amherst continues on his rounds. Amherst finds Scaler strangely knowledgeable about conditions on Ganymede for someone who claims never to have left Earth before.

Reaching Aquia, Amherst and Scaler find that its chief trader, Carl Kent, has gone missing; his teenage daughter Carol is carrying on in his place. Kent's disappearance is ominous since he has only recently worked out a process for distilling crephine from red moss. While Aquia is drowned in the flood, Scaler spends most of his time with Carol Kent.

A day and a half before the tide is due to ebb away from Aquia, Carol Kent discovers that her father's notes on his red moss distillation process are missing. Amherst remembers a rumour he heard that red moss has been discovered on Io; Scaler, he realizes, must be working for Ionian Products, a company seeking to break Cree, Inc.'s crephine monopoly. If they succeed, it will mean hard times for everyone on Ganymede. Aquia is searched for Scaler, to no avail. Suddenly one of the valves leading to the surface opens; Scaler is using it to escape Aquia with Carl Kent's notes. Amherst sends Kent to get him a vacuum suit; when she returns with it, she is wearing one herself. He tells her to remain in the settlement, but she ignores his order and follows him up the aqueduct.

Io (moon) Innermost of the four Galilean moons of Jupiter

Io is the innermost of the four Galilean moons of the planet Jupiter. It is the fourth-largest moon in the solar system, has the highest density of all of them, and has the least amount of water molecules of any known astronomical object in the Solar System. It was discovered in 1610 by Galileo Galilei and was named after the mythological character Io, a priestess of Hera who became one of Zeus' lovers.

On the still-half-flooded surface of Ganymede, there is no sign of Scaler, but Amherst and Kent see a rocket ship in the sky, coloured Ionian red. As the rocket nears the muddy ground, it lowers a ladder, then disappears behind a hill. When it reappears, a man is clinging to the ladder. It is Scaler, and Carl Kent's process is on its way to Io.

As they return to Aquia, Carol Kent tells Amherst about her father's process, which involves exposing red moss to ammonia and treating it with an extract from the eggs of Ganymedian gall-ants. Amherst is overjoyed: Ionian Products might have the process, but they don't have the gall-ants, and gall-ants can only breed on Ganymede. Carl Kent's notes will be worthless to the Ionians.


  1. In the introduction to A Martian Odyssey and Other Science Fiction Tales, introduction by Sam Moskowitz, Hyperion, 1974, ISBN   0-88355-152-7.

Related Research Articles

Callisto (moon) Second largest Galilean moon of Jupiter and third largest in the solar system

Callisto is the second-largest moon of Jupiter, after Ganymede. It is the third-largest moon in the Solar System after Ganymede and Saturn's largest moon Titan, and the largest object in the Solar System not to be properly differentiated. Callisto was discovered in 1610 by Galileo Galilei. At 4821 km in diameter, Callisto has about 99% the diameter of the planet Mercury but only about a third of its mass. It is the fourth Galilean moon of Jupiter by distance, with an orbital radius of about 1883000 km. It is not in an orbital resonance like the three other Galilean satellites—Io, Europa, and Ganymede—and is thus not appreciably tidally heated. Callisto's rotation is tidally locked to its orbit around Jupiter, so that the same hemisphere always faces inward; Jupiter appears to stand nearly still in Callisto's sky. It is less affected by Jupiter's magnetosphere than the other inner satellites because of its more remote orbit, located just outside Jupiter's main radiation belt.

Natural satellite astronomical body that orbits a planet

A natural satellite, or moon, is, in the most common usage, an astronomical body that orbits a planet or minor planet.

Ganymede (moon) The largest moon of Jupiter and in the Solar System

Ganymede, a satellite of Jupiter, is the largest and most massive of the Solar System's moons. The ninth largest object in the Solar System, it is the largest without a substantial atmosphere. It has a diameter of 5,268 km (3,273 mi) and is 8% larger than the planet Mercury, although only 45% as massive. Possessing a metallic core, it has the lowest moment of inertia factor of any solid body in the Solar System and is the only moon known to have a magnetic field. Outward from Jupiter, it is the seventh satellite and the third of the Galilean moons, the first group of objects discovered orbiting another planet. Ganymede orbits Jupiter in roughly seven days and is in a 1:2:4 orbital resonance with the moons Europa and Io, respectively.

<i>Farmer in the Sky</i> 1950 novel by Robert A. Heinlein

Farmer In The Sky is a 1950 science fiction novel by American writer Robert A. Heinlein about a teenaged boy who emigrates with his family to Jupiter's moon Ganymede, which is in the process of being terraformed. Among Heinlein's juveniles, a condensed version of the novel was published in serial form in Boys' Life magazine, under the title "Satellite Scout". The novel was awarded a Retro Hugo in 2001.

Moons of Jupiter The natural satellites of the planet Jupiter

There are 79 known moons of Jupiter. This gives Jupiter the largest number of known moons with relatively stable orbits of any planet in the Solar System, if one does not count the moonlets within Saturn's rings. The most massive of the moons are the four Galilean moons, which were independently discovered in 1610 by Galileo Galilei and Simon Marius and were the first objects found to orbit a body that was neither Earth nor the Sun. From the end of the 19th century, dozens of much smaller Jovian moons have been discovered and have received the names of lovers or daughters of the Roman god Jupiter or his Greek equivalent Zeus. The Galilean moons are by far the largest and most massive objects to orbit Jupiter, with the remaining 75 known moons and the rings together comprising just 0.003% of the total orbiting mass.

"The Mad Moon" is a science fiction short story by American writer Stanley G. Weinbaum, first published in the December 1935 issue of Astounding Stories. As did his earlier stories "A Martian Odyssey" and "Parasite Planet", "The Mad Moon" emphasizes Weinbaum's alien ecologies. "The Mad Moon" was the only Weinbaum story set on Io.

"Redemption Cairn" is a science fiction short story by American writer Stanley G. Weinbaum that first appeared in the March 1936 issue of Astounding Stories. "Redemption Cairn" is the only Weinbaum story set on Europa.

Tidal heating

Tidal heating occurs through the tidal friction processes: orbital energy is dissipated as heat in either the surface ocean or interior of a planet or satellite. When an object is in an elliptical orbit, the tidal forces acting on it are stronger near periapsis than near apoapsis. Thus the deformation of the body due to tidal forces varies over the course of its orbit, generating internal friction which heats its interior. This energy gained by the object comes from its gravitational energy, so over time in a two-body system, the initial elliptical orbit decays into a circular orbit. Sustained tidal heating occurs when the elliptical orbit is prevented from circularizing due to additional gravitational forces from other bodies that keep tugging the object back into an elliptical orbit. In this more complex system, gravitational energy still is being converted to thermal energy; however, now the orbit's semimajor axis would shrink rather than its eccentricity.

Jupiters moons in fiction depictions of Jupiters natural satellites in fictional stories

Jupiter's extensive system of natural satellites – in particular the four large Galilean moons – has been a common science fiction setting.

Magnetosphere of Jupiter Magnetosphere of the planet Jupiter

The magnetosphere of Jupiter is the cavity created in the solar wind by the planet's magnetic field. Extending up to seven million kilometers in the Sun's direction and almost to the orbit of Saturn in the opposite direction, Jupiter's magnetosphere is the largest and most powerful of any planetary magnetosphere in the Solar System, and by volume the largest known continuous structure in the Solar System after the heliosphere. Wider and flatter than the Earth's magnetosphere, Jupiter's is stronger by an order of magnitude, while its magnetic moment is roughly 18,000 times larger. The existence of Jupiter's magnetic field was first inferred from observations of radio emissions at the end of the 1950s and was directly observed by the Pioneer 10 spacecraft in 1973.

Exploration of Jupiter history of the exploration of planet Jupiter

The exploration of Jupiter has been conducted via close observations by automated spacecraft. It began with the arrival of Pioneer 10 into the Jovian system in 1973, and, as of 2016, has continued with eight further spacecraft missions. All of these missions were undertaken by the National Aeronautics and Space Administration (NASA), and all but two have been flybys that take detailed observations without the probe landing or entering orbit. These probes make Jupiter the most visited of the Solar System's outer planets as all missions to the outer Solar System have used Jupiter flybys to reduce fuel requirements and travel time. On 5 July 2016, spacecraft Juno arrived and entered the planet's orbit—the second craft ever to do so. Sending a craft to Jupiter entails many technical difficulties, especially due to the probes' large fuel requirements and the effects of the planet's harsh radiation environment.

The Planetary series of stories by Stanley G. Weinbaum is series of short stories, published in Wonder Stories and Astounding Stories in the 1930s, which are set upon various planets and moons of the Solar System.

Exploration of Io

The exploration of Io, Jupiter's third-largest moon, began with its discovery in 1610 and continues today with Earth-based observations and visits by spacecraft to the Jupiter system. Italian astronomer Galileo Galilei was the first to record an observation of Io on January 8, 1610, though Simon Marius may have also observed Io at around the same time. During the 17th century, observations of Io and the other Galilean satellites helped with the measurement of longitude by map makers and surveyors, with validation of Kepler's Third Law of planetary motion, and with measurement of the speed of light. Based on ephemerides produced by astronomer Giovanni Cassini and others, Pierre-Simon Laplace created a mathematical theory to explain the resonant orbits of three of Jupiter's moons, Io, Europa, and Ganymede. This resonance was later found to have a profound effect on the geologies of these moons. Improved telescope technology in the late 19th and 20th centuries allowed astronomers to resolve large-scale surface features on Io as well as to estimate its diameter and mass.

A planetary-mass moon is a planetary-mass object that is also a natural satellite. They are large and ellipsoidal in shape. Two moons in the Solar System are larger than the planet Mercury : Ganymede and Titan, and seven are larger and more massive than the dwarf planet Pluto.

<i>Jupiter Icy Moons Explorer</i> First large mission of Cosmic Vision; multiple-flyby reconnaissance of Europa, Ganymede, and Callisto

The JUpiter ICy moons Explorer (JUICE) is an interplanetary spacecraft in development by the European Space Agency (ESA) with Airbus Defence and Space as the main contractor. The mission is being developed to visit the Jovian system and is focused on studying three of Jupiter's Galilean moons: Ganymede, Callisto, and Europa all of which are thought to have significant bodies of liquid water beneath their surfaces, making them potentially habitable environments.

Mountains are widely distributed across the surface of Io, the innermost large moon of Jupiter. There are about 115 named mountains; the average length is 157 km (98 mi) and the average height is 6,300 m (20,700 ft). The longest is 570 km (350 mi), and the highest is Boösaule Montes, at 17,500 metres (57,400 ft), taller than any mountain on Earth. Ionian mountains often appear as large, isolated structures; no global tectonic pattern is evident, unlike on Earth, where plate tectonics is dominant.

The following outline is provided as an overview of and topical guide to Jupiter: