Syzygy

On 12th August 2026, a rare total solar eclipse will occur across parts of western Europe. The narrow band of totality sweeps across Spain and across the north Atlantic, touching Iceland. Here in the UK, the eclipse will be partial, blocking 93 per cent of the Sun’s disk in Coventry. So, to mark the event, let’s have a look at what the appearances of eclipses and alignments (collectively known as a syzygy) in science fiction reveal about their science.

[Note: I am considering astronomical syzygy. An alternate use of the term is in biology where it refers to a close interaction between organic units rather than stars. This use has also been picked up in SF, notably in the works of Theodore Sturgeon [1], but won’t be discussed further here.]

Eclipses as markers of dramatic events

We are familiar with the idea of an eclipse as the Moon passing between the Earth and Sun, or the Earth blocking sunlight from the Moon. These are particularly spectacular as the Moon and Sun make the same angle in Earth’s sky, allowing for perfect eclipses. However we also observe other eclipses in the Solar System on a regular basis. From our perspective, Mercury passes in front of the Sun (or transits) thirteen times per century. Venus transits the Sun in a pair of events separated from one another by eight years and from the next by over a century. Martian landers have observed transits of the Sun by Mars’s moons Phobos and Deimos, by Mercury and by the Earth. We have observed Jupiter and Saturn being transited by their moons on a frequent basis, and eclipsing them in turn (occulting them). We also see, albeit rarely, planets or stars being occulted by other planets or by the Moon, as a result of planetary alignments. Monitors on those planets or moons would observe Earth and other objects as transiting the Sun on a predictable schedule. All of these eclipses and alignments are examples of astronomical syzygy.

Traditionally, heavenly alignments have been viewed with suspicion and as omens of imminent disaster, or occasionally of a coming miracle. Eclipses and close conjunctions of planets in the sky have vied with comets as evidence that the events of significance are likely here on Earth - and these are common in fantasy, as, for example, in the film The Dark Crystal (1982, dirs: Henson & Oz), or when C S Lewis’ juvenile novel Prince Caspian (1951) features an alignment of planets (one passing in front of another) as a portent of the restoration of the long-suppressed Old Narnia. Given the Christian iconography that fills the Narnia universe, it’s worth noting that the Star of Bethlehem is widely believed to have been a planetary alignment observed by the Magi and presaging the birth of a savior. This is a theory which informs O Little Town of Bethlehem II (short story, Asimov’s, December 1985) Robert F Young’s unsettling story of a devoutly Christian settlement on another planet experiencing the moment when the light from Bethlehem reaches their new world.

Returning to the solar system, and on the boundary between science fiction and fantasy, the mutant superhero television series Heroes (2006-2010) also focussed its first season on averting a potentially catastrophic event which was to take place during a total solar eclipse, and used that eclipse as the emblem of the entire series. Similarly television series such as The X-Files (1993-2002) and The OA (2016-2019) have used ‘Syzygy’ as episode titles where an eclipse appears to have some paranormal or supernatural influence (whether or not this proves to be the case)

However other fiction uses the ability to predict eclipses as a way of establishing scientific authority and superiority over more ‘primitive’ beings - largely inspired a reported story regarding Christopher Columbus’s actions in Jamaica during a lunar eclipse in 1504. Sometimes the stereotypes in such situations are simply historical and somewhat problematic, as for example in Prisoners of the Sun (comic, Hergé, 1949) where Tintin uses it to awe native South Americans, and King Solomon’s Mines (novel, 1995 by H Rider Haggard) where it breaks a rebellion. However other examples are more clearly science fictional, such as the Doctor Who serial The Aztecs (TV serial, 1964) in which the Doctor does the same or Mark Twain’s A Connecticut Yankee in King Arthur’s Court (novel, 1889), where a time traveler from contemporary America is able to prove his ‘magical’ credentials by correctly anticipating an eclipse in the sixth century.

It’s interesting to note that a mistimed solar eclipse, occurring ten days earlier than predicted, serves the opposite purpose in apocalyptic movie The Day the Earth Caught Fire (1961, dir: Guest). It is not only the first sign that something has gone seriously wrong with the Earth, but also a sign that the scientists of England are not telling the whole truth about what they know or have been able to learn about the heat wave beginning to overtake the planet.

Appearing in Astounding Stories in March 1940, Nat Schachner’s novelette Cold also centres its pivotal action on the duration of an eclipse as seen from Uranus. The narrative follows a small group of miners - two Martian, two Earthmen, one neutral - in charge of gathering a resource unique to Uranus’ moon Ariel, and essential to life on the inner planets. It plays out the repercussions as the wonder-material appears to run out. As tension rises, the moon enters syzygy:

The shadows had deepened suddenly, and a weird purplish gloom settled over the fantastic terrain. I looked up. The tiny Sun was just going into eclipse behind the gigantic shoulder of Uranus. We had seen plenty of eclipses out here, but the sight of one always sent definite tingling along my spine. It was awe-inspiring. The quick drop in temperature - about sixty degrees in as many seconds, as the light cut off. The already glacial cold took on an added terror; the heating unit in my spacesuit required immediate stepping up.

At the climax of the story, the return of the Sun is emblematic of the return of hope to the situation.

Eclipses as culturally significant

Sometimes a syzygy is treated not only as signifying a single rare event, but rather as having a deeper cultural significance - even if this just mentioned in passing. In the William Tenn story Time Waits for Winthrop (Galaxy, Aug 1957), for instance, it’s mentioned that the last time a Ganymedean engaged in religion was during the last syzygy of Jupiter and the Sun. The cultural importance of eclipses appears elsewhere in science fiction, for example in the Star Trek universe, where Star Trek Discovery (TV series, 2017-2024) episode “Under the Twin Moons” focusses on a planet where a necropolis is built on the only point that experiences a double eclipse every seven years. Often this cultural reference plays a background role in establishing the depth and complexity of the culture in question, or establish the alienness of the planet or solar system. However sometimes the cultural impact plays a more prominent role.

In James Blish’s novella Get Out of My Sky (Astounding, Jan/Feb 1957), the twin worlds of Home and Rathe orbit their common centre of mass on their path around a white sun, accompanied by a trojan red dwarf, and illuminated by the nearby Canes Venatici cluster. Given the complexity of this system, it’s small wonder that astronomical alignments and events hold cultural significance to one of the worlds. As we’re told

"We are a custom-ridden people, with ceremonies for everything, all of them governed in turn by the positions of the Three Lights and the Sister World; this very conversation, for instance, cannot be prolonged one minute beyond one hour, for the stars would then be inauspicious. Is this clear, and, more important, is it credible?"

Unfortunately, the other world does not share faith in astrology of this kind. Despite that, their premier is asked to make a key speech against the backdrop of an eclipse:

His own world of Home was eclipsing the Cluster. The vortex of star-fire was already eaten away by almost a third. So this was what Margent had meant by saying that the stars were favorable!

This dramatic backdrop, and the darkness in a tall-sided auditorium which blocks the light from the two suns, ultimately adds power to his argument. Here cultural significance is harnessed in a conscious attempt to prevent interplanetary war.

A similar blend of superstition with cultural resonance can be found in Encounter with Tiber (novel, 1996, Aldrin & Barnes). This story describes an exomoon in the Alpha Centauri system which is threatened by extinction due to a rogue planet. The young people selected to make a journey to Earth, in the hope of saving their species, are taken to various cultural sites. Amongst these is the point on their Earth-sized exomoon, Nisu, directly beneath its gas giant primary, Sosahy:

The noon eclipse in Palath was the only time you could see the stars, because Sosahy, hanging over us in the sky, was bright enough to turn the sky blue most of the time. But right during the daily eclipse, Sosahy blocked the sun, and we faced the part of it that was having night, and then the stars would pop out.

This was the traditional location for the origin of their species, backed up by archaeological discoveries, and also significant as one of very few places where they can see the threat to life on their planet:

“The Intruder,” the captain agreed. “This is why we brought you to this place at this hour. Because you are standing where our species began to climb up toward the stars, and you are looking at the greatest threat to our existence.”

The tidal locking of moon Nisu to Sosahy, together with their binary suns, complicates the geometry of this system. It is nonetheless striking that this alignment is amongst the last experiences that the young explorers will have of their home planet.

Scientists viewing eclipses

For scientists, syzygies have an unending fascination. Huge amounts of information regarding a planet’s size, orbit and atmosphere can be acquired by careful analysis of the timings and light changes associated with the different stages of a transit. Perhaps natural, science fiction has explored these questions.

Arthur C Clarke’s Transit of Earth (short story, Playboy, Jan 1971) provides a poignant examples of this. The lone survivor of a party of astronauts stranded on Mars uses the last of his resources to carefully record and describe the 2nd May 1984 passage of the Earth and its Moon across the solar disk, as seen from the Martian surface. His careful concentration on recording each key moment in the transit, from the point of first contact to lunar first contact, and the passage of both bodies across the disk, is set against the tragic story of how he has come to this situation. In all honesty, while this is interesting - and a first for humanity - it’s not entirely clear what scientific information is meant to arise from this analysis for a civilisation which has already settled the Moon and possesses the technology (albeit in its early stages) to reach Mars.

A more positive view of scientific observations (albeit a significantly less accurate one!) was found in Amazing Stories magazine in December 1930. Eclipse Special by William Lemkin PhD described the development of the titular aircraft. This is designed to fly within the totality of a solar eclipse and around it in order to significantly extend the ability of the scientific community to study the eclipse (which is otherwise limited to a few weather-vulnerable minutes). Keeping up with the Sun’s shadow is not easy. As we’re told:

When the moon passes between the earth and the sun the shadow of our satellite strikes the earth's surface in the form of a circular dark spot and travels across it from west to east. The trail of this black spot across the earth is the path of total solar eclipse. Out in space, the shadow of the moon, or rather the apex of the shadow cone that is cast by the sphere, moves about 2,100 miles an hour. But when it strikes the earth, on account of the turning of the earth on its axis in the same direction in which the shadow is moving, from west to east, the shadow has to overtake and pass a moving point, and so its motion with respect to the observer is less than it is in free space. At the equator the observer is moving at the rate of 1040 miles an hour.

To achieve this, Lemkin invokes a mysterious force called the 'solunaray', which drags the plane along, but only when in the very focus of totality. His near-future also includes miraculous materials lying beyond our science, and even gravity nullifiers. Despite this, the newspaper-reporter narrator aboard his flying observatory gives an interesting account of the scientific studies undertaken. These include a lot of technical detail about issues such as studies of the corona, the chromosphere, and even the mountains on the Moon as revealed by the beads of light visible just to either side of totality. With the ability to navigate slightly ahead or behind of totality, these views can be recorded at the observer’s leisure. As fascinating as these studies are in their own right, tension is added to the story when the flying observatory loses the locus of the narrow solunaray, when it threatens to run out of fuel, and again when it looks like being swept off the planet as the eclipse nears an end.

A later story with a very similar theme is The Eclipse Express by John Russell Fearn (1952, writing as Vargo Statten). Again this imagines a special energy which is capable of pulling along a vehicle with the eclipse, in this case a space-capable rocket plane which is intended to be used in the upper atmosphere. Much smaller than the Eclipse Special, this vessel carries only a couple of crew together with photographic and television equipment transmitting to scientists on Earth. Again, there is a detailed account of the observations undertaken: 

No earthly spectroheliograph had ever revealed so perfectly the awesome marvel of that ruby chromosphere and prominences. No eyes chained to Earth had ever seen the corona so magnificently revealed—a blinding haze of pearly light sweeping out for millions of miles into the coal black of space. Travelling along in the track of the shadow was an unforgettable experience.

However after this, things get odder - a young woman stows aboard in the hope of proving that her inventor father has been stranded on the moon for years. The crew uses solar activity from sunspots to X-ray the moon, revealing a vast network of underground cities left by long-dead selenites (moon-dwellers), as she claims. Then the ship sets off to find the father on a second moon lurking in the Earth-Moon L-2 spot. And finally they take some problematic decisions regarding how to deal with the legacy left by the selenites.

Both of these novels clearly communicate both the importance and the difficulty of observing the Sun during a total solar eclipse. It is interesting that while both rely on cutting edge, modern technology that extended beyond what was possible at the time of writing, both also saw the need to include a fictitious invisible force to overcome the apparently insurmountable challenge of maintaining the required speed. In fact, when supersonic jet Concorde flew along the path of a solar eclipse totality over Africa for 74 minutes in 1973, performing several experiments in flight, it was able to maintain Mach 2 (1534 miles per hour) without any such force.

While astronomers still observe during natural eclipses, routine observation of the solar surface and corona are now carried out from space telescopes, some of which use a mask in front of the telescope to create an artificial ‘moon’ on demand. While certainly less exciting than an Eclipse Express, these platforms are more stable, and represent a technology which was arguably beyond imagining in the early twentieth century.

In more contemporary science fiction, scientific observing of eclipses and alignments is an occasional theme, although space travel allows observers to arrange their own alignments more or less on demand just by moving a spaceship or using a coronograph mask, reducing their impact. The television series Stargate: SG-1 (1997-2007) provides an interesting example in the early episode “Singularity” (1997) - in this story attempts to observe a black hole accretion disk during an eclipse is disrupted by an alien plot.

Disastrous alignments

Working astronomers also appear in what is undoubtedly the best known story in which an astronomical alignment leads not just to drama but to disaster: Isaac Asimov’s haunting short story Nightfall (Astounding, September 1941). This story considers an alien civilisation just reaching the stage of having advanced technology. Its archaeologists uncover evidence that civilisation has risen and fallen on their world many times before, with a peculiarly regular two thousand year cadence. At the same time, astronomers are unravelling the complexities of their six-star solar system. They come to a striking realisation: there is another body in the system which has not been seen before and which will only be revealed by an exceptionally rare eclipse:

“But only one sun lies in its plane of revolutions.” He jerked a thumb at the shrunken sun above. “Beta! And it has been shown that the eclipse will occur only when the arrangement of the suns is such that Beta is alone in its hemisphere and at maximum distance, at which time the moon is invariably at minimum distance. The eclipse that results, with the moon seven times the apparent diameter of Beta, covers all of Lagash and lasts well over half a day, so that no spot on the planet escapes the effects. That eclipse comes once every two thousand and forty-nine years.”

For a species that had evolved in a world which is always illuminated except for these rare half-day intervals, the idea of utter darkness is psychologically impossible to grasp or tolerate. The original short story follows the struggles of a university team to understand the implications of their discoveries as the disaster approaches, while the 1990 adaptation to novel length by Asimov and Robert Silverberg adds depth to this build up and also deals with the aftermath of the stellar and planetary alignment and the darkness it brings [2].

This story has had a huge influence on the genre and was instrumental in elevating the young Isaac Asimov to the status of a master of science fiction. However it’s not the only example in which a syzygy results in disaster.

Amongst these is the science fiction horror movie Pitch Black (2000, dir. Twohy). When a passenger spaceship crash-lands, the criminal being transported aboard is amongst the handful of survivors. He comes under suspicion when another survivor disappears, but it soon becomes clear that the planet hosts aggressive native life which has destroyed an earlier attempt at colonisation. This planet has three suns (two of them a close binary), in a system with a ringed giant gas planet and another planet, as revealed in the film when the survivors find an orrery. This shows the potential for a catastrophic alignment: the planet is subject to a lengthy total eclipse once every 22 years, releasing the native animals (normally cave-dwellers) to destroy life on the planet’s surface.

A longer much longer cycle is found in Anne McCaffrey’s Dragonriders of Pern series (beginning with Weyr Search, short story, Analog, 1967). Although superficially appearing to be fantasy, McCaffrey established that her Pern is a human colony around the star Rukbat (Alpha Sagitarii). The dragons are a native lifeform that is genetically engineered and increased in size by the early high-technology settlers to combat “thread”. This is a voracious alien lifeform that is carried from the Oort cloud by the elliptical orbit of another planet (the red star) and dropped into the orbit of Pern for fifty years out of every two hundred as the two planets remain close. Any thread that reaches the ground consumes any organic material it encounters, and infections must be burned out. It is unclear whether this is a true syzygy (i.e. alignment), although it would likely appear as one from elsewhere in the Rukbat solar system.

A more unambiguous example can be found in the 1973 novel by Michael G Coney, which is actually entitled Syzygy. This considers the effect that a lunar alignment might have on native life, as well as on human settlers. In the story, Arcadia is a human colony world, settled for a little over a century, with six moons visible from the ground. Once in 52 years, these moons align in the sky, leading to several weeks of dramatic tides and rare nighttime darkness. While elder colonists are curiously reticent about the riots and chaos that accompanied this event during the early days of sea-coast settlements, there is no real concern that the colony is prepared this time. However, as the director of a marine research institute quickly learns, the high tides trigger the spawning of the native plankton. In this process a mass of plankton forms a tight ball, which develops an emergent consciousness.

These Minds initially act instinctively, and later with intent, determined to protect themselves. Unfortunately they prove to generate a telepathic field which reflects strong emotion, leading to a spiralling feedback cycle of fear, anger and crowd mania, which magnifies existing tensions between independent settlers and government-sponsored researchers. The story ends with the hope that in another fifty-two years the colony will know what it’s facing and keep the situation under control - and a clear doubt that this will happen.

What’s interesting is the clear recognition in the text that it’s humanity’s decision to settle without fully understanding the ecological cycles of their new world that is at fault, rather than the native life.

Also culpable, to some extent, for their own fate are the human colonists of Ganymede in Robert Heinlein’s Farmer in the Sky (novel, 1950). In common with Heinlein’s other novels aimed at a juvenile audience, this follows a young protagonist as they adapt to a new environment. In this case, Jupiter’s largest moon Ganymede is the subject of a colonisation attempt which will allow a select few to escape overpopulated, starving Earth. During the early years of the colony a very rare syzygy occurs:

This is an event that almost never happens, Ganymede, Callisto, Io and Europa, all perfectly lined up and all on the same side of Jupiter. They come close to lining up every seven hundred and two days, but they don’t quite make it ordinarily,. You see, their periods are all different, from less than two days for Io to more than two weeks for Calisto, and the fractions don’t work out evenly.

…

Besides that, this line up was a line up with the Sun, too; it would occur at Jupiter full phase. Mr Hooker, the chief meteorologist, announced that it had been calculated that such a perfect line up would not occur again for more than two hundred thousand years.

This is a spectacular sight. Unfortunately though, the tides caused by an alignment of the four Galilean moons in a line between Jupiter and the Sun, together with the pressures caused by human efforts to heat Ganymede and provide it with an atmosphere, cause a devastating quake which comes close to destroying the colony. While this should probably have been expected and precautions taken, the rarity of the alignment is perhaps some excuse for the full implications not being considered. 

In fact, while an alignment of the Galilean moons like this would be spectacular [3], it’s unfortunately impossible due to the orbital resonance of the three inner moons. At most three of the moons can be on the same side of Jupiter at one time - the fourth might join the alignment from behind Jupiter, but not on the same side as described.

In a very different context, The Three Body Problem, Liu Cixin’s 2008 (trans. 2014) novel of conflict between Earth and the people of Trisolaris (a planet in the Alpha Centauri system) uses the fundamental instability of a three-body system as a key plot point. Here the three bodies are the stars of the system, rather than a star with planet and moon (a system is more stable if the mass ratio is high) but amongst the many disasters which regularly destroy civilisation on Trisolaris are syzygies in which all three suns align. In an illustration of such a case, people and objects are shown as pulled off the surface by the gravitational force of one such disaster. This is far less likely than a dramatic earthquake, but in this case is animated in a game so may have been a symbolic representation rather than a direct portrayal of reality.

Significant Syzygies

Here on Earth, solar eclipses are so rare and so spectacular that it is unsurprising that they became the focus of belief. The awe and wonder of such events add emotional resonance to fiction (as seen, for example, in Heroes or Cold), while their rarity adds drama. 

However for cultures, such as that of medieval christianity, the unchanging nature of the sky, together with geocentric models, has been seen as emblematic of deity and of humanity’s divine origin. The syzygies of other worlds in our solar system provided some of the key evidence in support of heliocentric models (i.e. those in which most objects orbit the Sun rather than the Earth, or are orbited in turn by their own satellites), and so became crucial in the gradual shift of western culture from being based on the received knowledge of religion to being based on the scientific interpretation of empirical evidence. The ability not only to predict both lunar and solar eclipses with precision but also to explain them demonstrated understanding of the elliptical, heliocentric orbits involved. Thus their use in science fiction (and other literature) to symbolise scientific knowledge, scientific research, and sometimes its ascendancy over traditional knowledge systems, is deeply rooted. The use of eclipses by Columbus in Jamaica, and its echoes in Tintin, Doctor Who and elsewhere is part of this story, but it also continues into stories of scientific investigations of eclipses, transits and alignments such as Transit of Earth or The Eclipse Special.

While the word itself is less commonly used, it’s interesting to note that a brief non-fiction article by A T Kenzie in Amazing Stories, Jan 1951 used the word ‘syzygy’ for a three-body alignment to emphasise the precision of technical language and its internationality. This kind of awareness of scientific accuracy was a feature of science fiction magazines of the mid-twentieth century. As the article concluded:

Words are a tool, part of the equipment for understanding the surrounding physical world. Without them you can’t get very far in anything. Keep your goal, your work and your ambition in "syzygy” – and you’ll do all right!

The extension of narratives of syzygies beyond the Earth and Moon to the outer planets and beyond to other solar systems is also reflected in the evolution of astrophysics. While we are not yet in a position to observe syzygies from other worlds (except, through robot proxy, from Mars), we are able to calculate their probability, characteristics and natures, as in this work from Dimitri Veras, one of my colleagues at Warwick. We also now routinely use particular types of alignment. One of the major methods for detecting planets around other stars (or their moons) is the transit method: looking for evidence that they are passing in front of their host star, causing small dips in light [4]. The same alignments of star-planet-Earth are used in transit spectroscopy - investigating exoplanet atmospheres by seeing how they modify the light of the star behind them. This is now everyday work for hundreds of astronomers worldwide, and thousands of transiting exoplanets are known. In many cases, these show eclipses from more than one planet, and overlapping transits - exosyzygies - are often observed.

https://www.eso.org/public/images/eso1706e/

In fact, such alignments are more common than might perhaps be expected. The very compact systems we are currently able to detect, such as the tightly-packed planetary systems of red dwarfs such as Trappist-1 often have planets locked into a resonance - i.e. if planet A orbits twice in a certain interval, planet B might orbit three times or five times, so that the planets appear to meet in their orbits at whenever their cycles complete. This is seen locally in the moon system of Jupiter, in Saturn’s rings and elsewhere. Resonances occur as the regular tug from a companion planet helps to stabilise orbits which might otherwise be disrupted by randomly timed tugs in different directions. As a result, such exosyzygies provide key evidence to help piece together a system’s stability and evolution.

While science fiction did not really anticipate the importance of transits in the exoplanet revolution, it does nonetheless explore some genuine potential consequences of alignments.

The tidal disturbance resulting from an exceptionally rare alignment such as that described in The Three Body Problem or Farmer in the Sky could indeed be significant (although in practice, the slightly different inclinations of the orbits and the orbital resonances make such a perfect alignment, in any order, in the Jupiter system extremely unlikely). Tidal forces are responsible for maintaining the core temperatures in many of the largest moons in the solar system, and - by inference - on other potentially habitable exomoons. Adding to those forces with rare alignments could indeed cause stress on the surface and interior of such worlds and, if frequent, could disrupt a moon into a ring system, or prevent one from forming [5]. 

It is also certainly plausible that animal life evolving on worlds with regular syzygies, as in the case of Pitch Black, could evolve to take advantage of it. Many species on Earth adjust their life cycles to seasonal variations, and occasionally to longer timescales - as in the well-known, multi-year, prime number cycles of cicadas. Any regularly occurring phenomenon that would give random mutations of a species a reproductive or survival advantage is likely to lead to cyclic behaviour as a result of well-understood evolutionary processes. Of course, this must be a frequent enough phenomenon to affect many generations of the species in question so that the survival trait is reinforced over time. Syzygies on the timescales of civilisations, as in Nightfall, are unlikely to produce evolutionary pressures, and the extreme situation in that story (six suns, a dark companion and a planet all on the edge of a globular cluster, all in a regularly eclipsing cycle) is unlikely ever to arise. It is nonetheless entirely possible that eclipses and conjunctions would take on cultural significance on other worlds (if sentient life there exists) as they have throughout human history.

Setting aside the scientific authority syzygies lend to science fiction, and even the practical effects, it is clear that to many authors the psychological and emotional effects of eclipses are just as important. The darkness, both physical and psychological, that is discussed in Cold or in Get Out of My Sky, reminds us of how dependent we are on the Sun, of the power it provides, and how shaken we can be by disruptions to the order of nature as we know it. Given the relatively simple relationship between the Earth, Sun and Moon, and the near perfect angular-size match of the latter two as seen from Earth, more complex syzygies provide a convenient shorthand for the alienness of other solar systems - and for their distance from our homeworld.

Alignments, conjunctions, occultations and eclipses all draw the attention of humanity into space. Their predictability is part of their wonder - a reminder that our understanding of the laws of gravitation is now well developed (albeit still not perfect). They are a triumph of science over superstition - and yet sights sufficient awe inspiring to send a shiver of superstition and emotion through even a strong rationalist. They continue to be studied scientifically, and have opened windows into new observational spaces never before considered. Their use in science fiction reflects, and has been shaped by all these aspects, and, to some extent, have helped shape popular understanding of them in term.