And Jupiter aligns with Mars
Then peace will guide the planets
And love will steer the stars"
Something in the plot depends on some stars or planets lining up in a particular order at a certain time (an event known in astronomy as syzygy). Often, doomsayers claim this will be the cause for The End of the World as We Know It, whether by breaking the tectonic plates, causing a shift of the poles, changing the Earth's rotation..., or introducing the Eldritch Abomination.
When it overlaps with Significant Birth Date, it can occur in the Back Story and still complicate the plot; this can produce The Chosen One or the Big Bad.
It should be noted, though, that due to distances involved and finite speed of light, the actual moment of planet's alignment would most likely NOT exactly correspond with its image in Earth sky. For example, light from Saturn took nearly 1.25 hours to reach the Earth. Which means, that by the time Earth observers would see Saturn in its "aligned" position, the actual planet would long ago move out of place. So if some nefarious plot required a ritual performed exactly at the moment of all planets being in line, trying to perform it at the moment where planets VISIBLY (from Earth) being in line would most likely lead to dismal failure.
- Celestial Deadline: where you can use these sorts of events.
- Total Eclipse of the Plot, a Sub-Trope which involves a solar eclipse.
- Vicious Cycle, because these alignments tend to occur at regular intervals. Example: The Dark Crystal (Great Conjunction of suns).
- Artistic License – Space: some examples fall into this category.
- Liminal Time: Another way to lend significance to a date.
- A Year and a Day, where the countdown is not to some specified event but is tied to the passage of a fixed length of time.
- Queen Millennia: According to Yayoi, the reason this passing of La-Metal would be disastrous for Earth after all this time is because of the coincidental planetary alignment in 1999 has shifted its orbit closer to Earth, previous times it wasn't as close. Later she clarifies that La-Metal may have deliberately arranged it to happen, which is proven with Larela's device affecting gravity of remote objects.
- Saint Seiya: During the Hades arc in which the 9 planets (remenber, back then Pluto was still considered a planet) will all align together and cause the Greatest Eclipse.
- In GO-GO Tamagotchi!, the Tamagottsun is an event that happens every 1,000 years when Tamagotchi Planet aligns with Planet Earth. The result is that the continents on Tamagotchi come together to celebrate, causing Tamagotchi Town and Dream Town to merge into a single location.
- Age of the Wolf: A werewolf prophecy says that humanity can be wiped out if a particular human is sacrificed when the great moon aligns with the stars.
- In Bring Me to Life, it's eventually revealed the First's plan revolves around an event known as the Awakening, which is when every world, star, and dimension in The Multiverse is in perfect alignment with each other, something that only happens every half billion years. When this happens, the First will be able to access the Eye of Creation and use its raw power to destroy all of reality.
- A Frozen Flower:
- In Chapter 9, "Farewell to the Monsters", Orchid is told by Till that when she was born from a Crack in the Sky, five stars aligned above the crack and she pulled all of their energy into herself. Presumably, this is why she is as uncontrollably powerful as she is, although it's never explained.
- Later on in the same chapter, Otto temporarily gains lambero powers when he takes the bullet for Oprah and he absorbs Grimes's energy blast. Five stars align above him in the sky at the moment he gets the powers, which allow him to fight back against Grimes and his group of dormant lamberos.
- The New Adventures of Invader Zim: The plot of Season 2 Episode 7 is kicked off by the Stellar Shower, a cosmic energy storm that passes by Earth every 857.3 years. When Viera comments on the oddly specific number, Steve counters that while magical events seem to always round to the nearest hundred years, scientific ones bound by physics aren't quite so even.
- Hercules: The Titans can only be freed when the planets line up. Notably, it is only the further six planets (well, five planets and Pluto, but it was considered a main planet back then) which apply, as their alignment basically reveals the location of the Titans' prison and unlocks it, enabling Hades to free them.
- Frozen (2013): Part of the All There in the Manual explanation for Elsa's ice powers is this. According to Word of God, 1,000 years after Saturn is in a certain alignment, a child is born with ice magic. This was going to be explained in the film itself but was cut for not being important to the focus of the film. This was eventually retconned out in the sequel when it properly explains her powers.
- TMNT (2007): The portal to the netherworld opens when the stars line up.
- The Coneheads' symbol of their home planet represents three crescent moons overlapping. When the Coneheads finally return, it does indeed have three moons that periodically align in this way, instigating a major festival.
- The plot of Pitch Black revolves around a 22-year cycle eclipse of all the suns of a planet.
- In Highlander: The Source, the entire galaxy—every single celestial body from moons to planets to stars, and all of them in the solar system—comes into alignment, all focused on Earth. Even non-scientists and children knew better, but that didn't stop the writers.
- Omen III: The Final Conflict. The alignment of three stars creates the second Star of Bethlehem, a sign of the Second Coming of Christ.
- Lara Croft: Tomb Raider. A magic item that can be used to control time can only be accessed during a planetary alignment that occurs once every 5,000 years.
- The Dark Crystal involves a triple-sun alignment called the Great Conjunction.
- 2012 vaguely waves at this, with another planet visible from Earth's orbit and Jupiter visible from Saturn, but apart from Woody Harrelson's free-associating Conspiracy Theorist, it doesn't come up again.
- In The Scorpion King, the villain will allegedly become invincible when the Moon is in "the House of Scorpio".
- The Mac Gyver Lost Treasure Of Atlantis TV-movie features this. For some reason, the planets are visible, to the point where they would actually collide with each other.
- Pee-wee's Big Adventure - after his bike was stolen, Pee-wee has all his friends assemble in his basement as he manically pieces together clues to the crime - including planetary alignment.
- A major plot point of Thor: The Dark World is the Convergence, an alignment of the Nine Realms that only happens once every 5000 years, causing portals between the worlds to open at random. Malekith intends to use the Convergence to spread the Aether across the universe, destroying everything.
- 2001: A Space Odyssey: In "The Dawn of Man", the first Monolith appears to the Australopithecines when the Moon is near solar eclipse; the Monolith on the moon sends its transmission to Jupiter when the Moon is near lunar eclipse. In "Jupiter and Beyond the Infinite", the portal opens with an alignment of the Monolith and the major Jovian moons.
- In Headless Horseman, the Horseman rises once every seven years on all Hallows Eve when the entirety of the constellation Hydra is visible in the sky.
- 5/5/2000, ICE: The Ultimate Disaster claimed that on the title date, a planetary alignment would cause catastrophic disaster on Earth.
- Robert A. Heinlein's Farmer in the Sky featured a dramatic alignment of the moons of Jupiter which the protagonists watched from Ganymede.
- In Kushiel's Mercy, the Carthaginians take advantage of an astrological event to put a spell on the entire city.
- One of the stories in Star Trek: The Brave And The Bold involves a Bajoran prophecy suggesting Bajor will be at peace when all the planet’s moons fully align. The bitter old terrorist Orta seeks to use a powerful artifact he’s unearthed (created by Sealed Evil in a Can Malkus) to artificially move a moon and fulfill the prophecy early. Of course, he doesn’t actually want peace — he’s just using the prophecy as a ploy to start a conflict with the Federation.
- In the Cthulhu Mythos universe by H. P. Lovecraft and others, there are many references to how the Great Old Ones will return "when the stars are right".
- In the famous story, The Call of Cthulhu, the narrative states that Cthulhu had been awakened by ignorant sailors because "the stars were right again" when the sailors discovered the uncharted island. The cultist ritual that's broken up in an earlier part of the story may also be responsible; something made the island briefly rise to where they could find it...
- Though it's never explicitly said what that entails. In fact, an alternate interpretation at least in Cthulhu's case is that it refers to the Elder-Things (who may or may not have been responsible for trapping Cthulhu underwater to begin with) which are described as having star-like heads.
- It's worth noting that this is also how Cthulhu is returned to dormancy at the end, as the stars come out of alignment and the sailors stopped him from escaping completely.
- One of the lesser Dragonlance novels featured a portentous lunar alignment between the white, red, and black moons of Krynn, known as the "Night of the Eye".
- In John Brunner's The Traveller in Black series, the Traveller makes his periodic journeys when a certain array of four planets comes into alignment.
- Two alignments of the seven planets play a major role in the timing of the third book of the Septimus Heap series.
- A variation occurs in the backstory of John Bellairs' young-adult horror novel The House With a Clock in Its Walls, with black-magic user Isaac Izard obsessively searching for the right pattern of clouds to allow him to bring about The End of the World as We Know It. After he misses the moment, he creates the titular clock to try and drag time back to the right position again.
- In Robin Jarvis' Deptford Histories book Thomas, a constellation of nine stars in the sky signify when the serpent God of Evil Suruth Scarophion is closest to the living plane.
Nine bright stars from out the void, shining up on high
Whose banished soul do they call back and augur in the sky?
Despoiler of the ancient lands, who baked the deserts dry.
Scarophion, Scarophion - the demon is close by.
- In Demi's The Hallowed Horse, the titular lord of all equines can only be born at a certain time, when astronomical conditions are right. This is how the royal sages pinpoint where he is, although none of his previous or current owners understand his true worth- they just ask the horse trader, "Were any of your foals born on this date?"
- Monster of the Month Club:
- The monsters are only active when stars line up in angled shapes like lightning, and only some of them each time - the April and May monsters are both from South America, so the same stellar alignment awakens them, while the June Selection (who's from Portugal) only awakens after Chelsea and Burly go back to sleep. Likewise, the July, August, and September monsters are all from Asia and so are logically active together. Rilla does note in book 2 that she's not sure why Icicle and Sweetie Pie were active at the same time since Botswana and New Zealand are far away from one another and couldn't be affected by the same star pattern.
- Another cosmic alignment in December, in which there's both an eclipse and a comet in the sky at the same time, allows all twelve to be active at once for the duration of the eclipse. The comet's presence also causes the October, November, and December monsters to randomly activate and deactivate during the month.
- The X-Files episode "Syzygy". An alignment of Mercury, Mars, and Uranus may have something to do with several murder cases in a small town.
- Astronomer Sir Patrick Moore appeared on Have I Got News for You at a time when an impending alignment of the planets was being hyped in the tabloids as a catastrophe. Angus Deayton gave him pieces of fruit to represent the planets and kept referring back to the rumors, even though what Moore was demonstrating with the fruit was that absolutely nothing was going to happen.
Angus Deayton: This is the prediction that Jupiter and Saturn will align with Mars, Venus, and Mercury in the year 2000, which will cause flooding, earthquakes, and tidal waves. The planetary alignment will cause gravitation forces from the Sun to...
Paul Merton: No, it won't! Patrick says it won't!
Ian Hislop: There isn't a lot of point getting an astronomer on if you're just going to read out a load of balls!
Paul Merton: Ian, the correct term is spheres.
- On another occasion, Sir Patrick announced on radio that a rare alignment of the planets would temporarily reduce the Earth's gravitational pull, as people could discover by jumping up and down. Several listeners called in to confirm this, one man claiming that he had bumped his head on his ceiling. The fact that the broadcast went out on April Fool's Day seemed to have escaped their notice.
- The first half of Rescue Sentai GoGoFive had the Saima preparing for the planets to line up into the Grand Cross so they can bring back Grandienne. This carried over to their American counterparts in Power Rangers Lightspeed Rescue. Like with Dengeki Sentai Changeman and Halley's Comet, in August 1999, the Grand Cross occurred as well.
- In episode two of Tensou Sentai Goseiger, Hyde is told the Gosei Angels can only return to their own world during a solar flare that occurs once every 200 years. Unfortunately, at that time they are fighting a Monster of the Week, and he decides to remain on earth instead to protect the earth with the others.
- Doctor Who
- In "The Masque Of Mandragora", the astrologer Hieronymous invokes this for his fake predictions, and may even believe it. Certainly at the end of the episode the Doctor warns that the constellation the Mandragora Helix is in will be in the right position for another attempt to conquer Earth in 500 years. Given that their adventure takes place during the Rennaisance, this would be the late twentieth century...
- The series four finale ("The Stolen Earth"/"Journey's End") had twenty-seven planets stolen from their home systems and placed in perfect alignment by the Daleks to create an engine to be used to amplify the "reality bomb" that would destroy every universe in all of reality.
- H₂O: Just Add Water: The Lunacy that affects the mermaids whenever the full moon rises has different effects depending on the position of the planets. Lewis is the only one interested in researching the astrological effects on mermaids; the mermaid trio tends to tune him out whenever he brings it up. The full moon during the episode when this comes up turns out to be particularly aggressive (and coincides with the trio's Seventh Moon Cycle, which Mako Mermaids would reveal comes with a sudden increase of a merperson's power), causing the trio to nearly murder Lewis with their new Weather Manipulation powers. A different full moon that happens once every fifty years can permanently Depower a mermaid who happens to be in the Moon Pool.
- Star Fleet has all the planets in Earth's solar system aligning at the end of the year 2999 for the dawn of a new millennium.
- The Sarah Jane Adventures: The Ancient Lights. Their master plan relied on every star in the universe entering into a very specific pattern.
- The Tin Man mini-series has the Big Bad plan to use a Magitek machine to "freeze" the Outer Zone's two suns in a permanent position behind the moon, thus placing the OZ in perpetual darkness.
- Land of the Lost (1991) had an episode where the animals were going mad due to the world's three moons aligning.
- Buffy the Vampire Slayer: In Season 5, it's stated that the Key can only be used to open portals at a specific time and place, and Glory's minions have to repeatedly remind her she's running out of time to find it. In "The Gift," the Scoobies use this to their advantage; since the ritual can only be performed at said specific time and place, all they need to do is keep Glory occupied until her window of opportunity passes.
- MacGyver (1985): "Lost Treasure Of Atlantis" features this. For some reason, the planets are visible, to the point where they would actually collide with each other.
- It has been suggested that the star which guided the Wise Men to Jesus' manger was not actually a star, but a particular astronomical alignment.
- On Dec 21, 2020, there was a conjunction of Jupiter and Saturn dubbed the "Christmas Star". Given the events of that year, some were surely disappointed that it didn't herald the Second Coming.
- Dungeons & Dragons
- Adventure "Sign of the Times" in generic AD&D2 supplement Treasure Maps. Every 700 years during a specific astrological conjunction of planets, moons, and stars the king of a desert empire will fall ill and die, and his son will take his place. The new king will become evil and cruel, raising taxes and invading other countries. Natural disasters (famine, pestilence, and drought) will ravage the land.
- Al-Qadim setting, in The Complete Sha'ir's Handbook, has a Wizard kit "Astrologer", with a shade of Mad Scientist, who have to play with an orrery and may have up to 3 bonus spells discharged at will, but conditioned on visibility of one of 12 constellations.
- Violet Dawn setting has feat "Secrets 0f the Stars" in one tradition. It allows predicting a "propitious time" for some or other activity involving XP cost (i.e. item enchantment or casting powerful spells), sticking to which halves said cost.
- The Forge World Warhammer 40,000 supplement The Fall of Orpheus's villains, a slumbering (and insane) Necron dynasty, come to full wakefulness immediately following a binary system's two suns suddenly go nova, altering the appearance of the stars in the Orpheus Sector and meaning that The Stars Are Right once again. Needless to say, it ends badly for the population.
- In Rifts, The Great Cataclysm occurs during (and in part because of) a rare conjunction of the planets. It caused the Ley Lines to surge with power. This combined with a couple other factors upset the Earth's magical balance, causing The Coming of the Rifts.
- In Yu-Gi-Oh!, this is referenced in two cards, Grand Convergence and the anime-exclusive Planet Alignment. The former destroys all monsters on the field, the latter just your opponent's, but both feature planetary alignments in their card art.
- Hair references the trope during the "Age of Aquarius" song: "When the moon is in the seventh house and Jupiter aligns with Mars/then peace will guide the planets and love will steer the stars"
- Subverted in Crash Bandicoot 2: Cortex Strikes Back. Crash's goal is to gather Crystals so Cortex can use them to safeguard the world from a planetary alignment (all thirteen of them). Of course, he's lying - the Crystals are actually to fuel a space weapon.
- For the King: The plot of the Lost Civilization DLC involves a Mayincatec cult attempting to bring about an apocalypse via a planetary alignment. As the alignment approaches, it begins to have noticeable in-game effects such as the protagonists taking "sunburn damage" at the end of every daylight turn if they're not indoors.
- The aforementioned song from Hair is referenced in Quest for Glory II, by the astrologer:
"When the moon is in the seventh house, and Jupiter aligns with Mars...then peace will guide our planet and love...? Naw, it'll never happen."
- The World Ends with You: When six darklit planets align...
- Pious Augustus of Eternal Darkness is counting on the planets aligning to channel enough power to summon his Ancient into the mortal world. He's been waiting for two millennia for this event which of course is at the Turn of the Millennium.
- Master of Magic has astrological conditions — Conjunctions, Good Moon, and Bad Moon — that enhance one type of power source and diminish others. These are really random events, though, i.e. have unpredictable start and end times.
- In Psygnosis' Lander, a conjunction of all nine planets in our system allows space tourists the once-in-a-lifetime opportunity to visit all the planets in a single cruise.
- A Miracle attack in Animal Kaiser called "Aligned Planets". Apparently, when this happens, all of them smash into Earth and destroy it in a cutscene... and the opponent animal takes heavy damage, with Earth no worse for the wear.
- Ultima VII: The astrological alignment of the nine planets of the solar system occurs once every 800 years, thinning the barriers between worlds, and increasing magical activity. During this event, The Guardian attempted to enter Britannia through the Black Gate.
- RuneScape: The Mahjarrat perform the Ritual of Rejuvenation, where one of them is sacrificed to extend the lives of the others, during a planetary alignment that happens approximately once every 500 years. The planetary alignment isn't actually a necessary component of the ritual, as it can be performed without it. They just do it at that time because once every 500 years is often enough to keep the surviving Mahjarrat alive, but not so frequent that their numbers would be reduced too quickly.
- Persona 2 Innocent Sin: The entire game is based on all the doomsday theories surrounding the Grand Cross of 1999 actually coming true due to the interference of an Eldritch Abomination. Cue Class X Apocalypse How. In Eternal Punishment, it's become a minor background element whose only significance is that absolutely nothing of note happened during it... acting as an absolute confirmation that the events of the prior game never came to pass in this timeline.
- Likely a coincidence, but the opening of the second act of the The New War from Warframe shows all of the planets, moons, and other visitable celestial bodies in the game in alignment during a cinematic narrated by Ballas. Not only does this make it roughly coincide with the arrival of the main army and fleet of the Sentients, who go on to defeat the Tenno and conquer the system, it also occurs when the Drifter, an Alternate Self to the Operator, arrives in the system to resolve a paradox involving the Zariman Ten-Zero.
- Ratchet & Clank (2016) adds this to the plot of the movie: the Deplanetizer destroying an entire system by firing at Umbris is only possible thanks to the planets aligning at that time. The alignment itself is foreshadowed by a radio news item at the very start of the game.
- Wapsi Square: You know what happens in 2012 when the Mayan calendar runs out? "Groundhog Day" Loop!
- Eerie Cuties has a vampire born on the first Sunday after the first full moon after the vernal equinox (a.k.a. Easter) who does not drink blood.
- Dork Tower lovecraft is
- In Cucumber Quest, the Nightmare Knight returns every 5,000 years.
- Adventure Time: "The Mountain" features the Dap of the Heavens, a celestial event that makes it look like two constellations are fist-bumping.
- Rocko's Modern Life episode "Born to Spawn." Filburt's breed of turtle has a mating season that occurs when all the planets are in alignment and is hypnotically irresistible. In the end, Heffer has a similar problem starting when all the fast food restaurants go into alignment.
- In Teen Titans (2003), it's said that Trigon could only arrive on Earth when the planets align. We don't actually get to see any planetary alignments, but there is a freaky eclipse going on simultaneously.
- In Invader Zim episode "Career Day", some paranormalists discovered that when a galactic equinox occurs, aliens that are living off their home planet will go through a hideous molt for a few minutes. Zim just happened to be unlucky enough to experience it.
- Major plot points of the nine-month (literally three seasons) storyline of Avatar: The Last Airbender include the solstices, a solar eclipse, a (man-made) lunar eclipse, and a comet with a 100-year cycle.
- The Legend of Korra: Every 10,000 years, the planets align in what is known as the "Harmonic Convergence"; on that day the spirits Raava and Vaatu do battle to decide the fate of the world, and while neither one can permanently kill the other it's a very bad thing for everyone if Vaatu wins. During the previous Convergence, the first Avatar, Wan, merged with Raava and sealed Vaatu in a tree. The next Convergence is on Korra's watch.
- In My Little Pony: Friendship Is Magic, Nightmare Moon is said to return on the longest day of the thousandth year when the stars will aid in her escape.
- In Teenage Mutant Ninja Turtles (2003), the underground city's crystal technology is recharged completely with the coming of the planetary alignment, which allows the city's inhabitants to revive themselves.
- In the Spongebob Squarepants special "Spongebob vs The Big One", Jack Kahuna Laguna explains that when the planets align, it creates an incredible wave called The Big One, which the heroes can use to surf back home. Unfortunately, The Big One also demands a sacrifice for the rest to survive.
- A teaser for the second season of Transformers: Prime ties such a prophecy with the awakening of Unicron:
Optimus Prime: And it was written in the Covenant of Primus that when the forty-seven spheres align, a perpetual conflict will culminate upon a world forged from chaos; and the weak shall perish in the shadow of a rising darkness.
- Somewhat Hand Waved by the fact that gravitational forces from those planets were somehow acting on Unicron, causing him to wake up.
- According to the introductory narration, the reincarnation of Count Duckula may occur by means of a secret rite that can only be performed once a century when the moon is in the eighth house of Aquarius. It is imperative to make sure only blood (any kind) is used in the ritual however, otherwise there will be side effects.
- Camp Lazlo: Small children depend on the alignment to gain maturity to watch horror movies. It's supposed to occur every time someone reaches puberty but it seems to have missed Mr. Lumpus.
- Xiaolin Showdown: On the day the planets aligned, Mala Mala Jong reforms and then uses the Ring of Nine Dragons to split into four beings collectively called the Fearsome Four. Luckily, this reveals a new Shen Gong Wu artifact to defeat him, the Emperor Scorpion, which lets him be controlled.
- In ˇMucha Lucha!: The Return of El Malefico, El Malefico can only be set free when this happens. If he's not put back by the time they come out of alignment, he becomes unstoppable.
- Scooby-Doo! Mystery Incorporated had a story arc leading to an alignment of the planets with a Planet X, which was inhabited by what was believed to be the first recorded history of gods. At that point, the curse of that timeframe, Nibiru, would be released and ravage the earth and we do mean ravage.
- Wander over Yonder
- In "The Picnic", a planetary alignment once a millennium brings forth a transdimensional creature who will grant one wish to whoever is present. Lord Hater and Emperor Awesome fight over the spot where the creature will appear and wish to be ruler of the universe, while Wander is there just to watch the alignment. In the end, Lord Hater gets the wish, but wastes it on wishing that Wander leave him alone for five seconds.
- In "The Time Bomb", an annual planetary alignment provides the perfect set-up for a massive race, the Galactic Conjunction 6000.
- When the Three Suns of the planet Prysmos align at the beginning of Visionaries, the planet's advanced technology starts to fail. Before long, all electrical energy has been depleted and an Age of Magic has begun, but it takes a few years before people believe this.
- The Secret Show has a pair of magical clown pants that activate every 30,000 years during a planetary alignment, enabling the user to suck anything into the pockets of the pants. Including the entire universe, which is weaponized against Doctor Doctor when she gets ahold of the pants.
- The Smurfs (1981): In the episode "Gargamel's Quest", a planetary alignment one night causes the Smurf Village's protection spell to be temporarily lifted and a light to shine on the village, giving Gargamel a direct line to invade and attack the Smurfs.
- Class of the Titans: The series starts with the planets aligning, causing Cronus to escape from his prison in Tartarus. Cronus would antagonize our heroes for the entire rest of the series.
- Courage the Cowardly Dog:
- In the episode "Everyone Wants to Direct", zombie director Benton Tarantella arrives on the farm to direct a film, but in reality, when the planets align, his partner, Errol Von Volkheim, will rise from the grave due to the farmhouse being built over a cemetery that went out of business and both zombified men will eat Muriel, whom they cast as their victim.
- In "So in Louvre are we Two", Courage, Muriel, and Eustace are locked in The Louvre in Paris after dark and witness the alignment of the planets causing the art in the museum to come to life and be able to leave their pedestals/frames.
- Masters of the Universe:
- He-Man and the Masters of the Universe (1983): In "Teela's Quest", Mer-Man explains that the sea demon Bakull can only be summoned when the stars are in perfect alignment, which only happens every twenty years.
- In She-Ra: Princess of Power, there was an attempt to kidnap Prince Adam from Eternia by using a mirror that can open portals. The problem is, it only works when the two moons (two for each planet, that is) are aligned. The attempt is successful, but when Hordak later orders to use it when the moons aren't aligned, it turns out to be a really bad idea.
- In Masters of the Universe: Revelation, the Celestial Apex is the rare moment when Eternia's rotation will put it in the physical center of the universe. As the Cosmic Keystone for all magic in the universe, that magic will flood back into Eternia during the Apex. Whoever wields the Power of Grayskull at that time will have so much magic at their command that they will be a Reality Warping Physical God.
- The tide. Not exactly planets, but springs and neaps are caused because of the gravity of Sun and Moon.
- Voyager 2's trajectory took it past Jupiter, Saturn, Uranus, and Neptune, due to a planetary alignment that only occurs once every two or three centuries.
- The Jupiter Effect was a 1974 book that predicted that a planetary alignment on March 10, 1982, would have disastrous effects on Earth. (It didn't.)
- On roughly December 21 every year, Earth, the Sun, and the galactic center line up (almost: the galactic centre (Sagittarius A*) is seven degrees away from the ecliptic). Some people, not realizing it happens every year, predicted this would have dire consequences in a specific year.
- The small asteroid Apophis will approach Earth in 2029. If it had passed through a "keyhole" (a certain set of trajectories) it would have been on course to hit Earth in 2036. (Later observations showed it deviated from the "keyhole" and will not hit Earth.)
- The "Jovian-Plutonian Gravitational Effect" hoax of 1976 by the British astronomer Patrick Moore. The guy stated to radio listeners that an alignment of Jupiter and Pluto on 9.40 am, April 1, 1976, will noticeably reduce gravity on Earth. Many believed.
- A regular alignment of moons about their planet or planets about their star is known as orbital resonance, and can lead to some interesting gravitational effects. In particular, a 2:1 resonance between Jupiter and Saturn in the early solar system may have affected the orbits of Uranus and Neptune and led to the Late Heavy Bombardment of the inner planets by asteroids from the outer reaches of the system.
- The phrase "when the stars are right," along with its variants, is sometimes used to refer to necessary conditions which are difficult to arrange or cannot be readily determined, especially referring to computer use or programming.