"It's called a constant. Desmond, you have no constant. When you go to the future, nothing there is familiar. So if you want to stop this, then you need to find something there...something that you really, really care about...that also exists back here, in 1996."
When you Time Travel
, or you spend some time as a Human Popsicle
, or even just leave a place for a long time, things tend to change a lot. But even when almost everything has changed, there's some character or thing that exists in both time periods, not because of time travel, but because they remained there the whole time
. They are The Constant, and they connect two different-looking settings together and prove they're the same place.
Frequently the work will go out of its way to make a point of The Constant, and in our examples we focus on these intentional, obvious Constants. If the time-traveling character didn't realize they were in the same place until discovering The Constant, then you have Earth All Along
If the time travelled was too short, there may be so many Constants that it's unremarkable. For example, it's not uncommon for the entire cast from the past to switch to Future Badass
versions of themselves in the future. On the other hand, there is no minimum time difference - a city may be reduced to an unrecognizable place overnight by a terrible weapon, except for The Constant proving it was there. Or as Nena would say, "If I could find a souvenir / Just to prove the world was here."
If the time traveled is very long, the Constant will typically be a structure or an immortal rather than an ordinary person. If it is a person, it's usually the Identical Grandson
or a variation thereof (such as My Grandson Myself
Compare Earth All Along
, Monumental Damage Resistance
. Often invokes Never Recycle a Building
If everything inexplicably survives in a slightly distressed state, it's a case of Ragnarok-Proofing
If the Constant in question ends up being destroyed in real life (e.g. the World Trade Center), can result in a "Funny Aneurysm" Moment
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Anime and Manga
- Cowboy Bebop: When the de-frosted (on two levels) amnesiac Faye Valentine returns to Earth, she meets an old classmate of hers, now an old lady.
- The Sacred Tree in InuYasha. In the past, it's where Kagome meets the titular Inuyasha; hundreds of years in the future, it's still tended by her grandfather, even though a modern city has grown up around it. The nearby Bone-Eater's Well also exists in both times and acts as a Portal to the Past while it's at it.
- In the movie Pokémon 4Ever, the young woman Sammy meets is an old woman 40 years later when he meets her after a time trip.
- An American artist once released a poster with a series of pictures showing how a patch of land developed over a hundred years from open prairie into a busy city. Through it all one thing remained: A slowly growing tree.
- The American Flag in The Ultimates. The newly thawed out Captain America is despondent over how different things are. Technology has advanced massively, his high school friends, fiance and army buddies are in their 80s and modern morality is completely different than the 1940s. That is until Nick Fury points out the American flag over a cemetery and comments that one thing hasn't changed. (Well, except those two extra stars from 1959.)
- Robert Crumb's Mister Natural once had an immensely satisfying meditation in the desert. It starts when he arrives in a desolate spot, spreads out his blanket and assumes the lotus position. Some indeterminate time later, construction workers arrive to build a road past him. He remains transfixed even when junk thrown from passing cars bounces off his head. Eventually a small town grows up around him, and after what appears to be years of development he is finally noticed as a policeman brusquely orders him to move, he is blocking the traffic. (Apparently they managed to build the sidewalk under him.) The guru's only answer is a slowly rising hum that after a few panels causes the officer to flee in panic as the buildings around them crumble into dust. Once the location is back to its original state (you know, apart from the fact that the "sand" now consists of pulverized concrete, glass and asphalt) Mr. Natural stops humming, gets to his feet, stretches and yawns, declares "That was a good one!", rolls up his blanket and wanders off.
- Vandal Savage acts as this sometimes for the DCU, since his complete unkillability allows him to survive pretty much any changes that would kill off everyone else.
- The Christopher Reeve movie Somewhere In Time features an elderly hotel employee who recognizes the hero from his childhood - much to the hero's confusion, because from his perspective that event hasn't happened yet (he later goes back in time and meets a boy in the lobby who is clearly the same guy).
- In Inception, the folks who enter dreams carry a "totem", a small personal item that they alone know the exact size and weight of, to help them remember if they are in reality or dream state if need be. For instance, lead protagonist Dom carries a top that will spin endlessly in a dream, but topple in reality. Growers of Epileptic Trees may find some fertilizer in the observation that the viewer does not see it topple before the movie cuts to credits.
- Although Word of God states that it does in fact topple.
- The Statue of Liberty in the Planet of the Apes movie that features so prominently in the Earth All Along.
- The Clock Tower in Back to the Future in a major example of this trope, as it appears under construction in 1885, working just fine in 1955, broken and run-down in 1985, transformed into a casino-hotel in the alternate 1985, and as a piece of high-tech modern art in 2015.
- Doc Brown serves as one in the first film, as well, moreso than Marty's parents or Biff, as he is aware that Marty has been time-travelling.
- In the George Pal version of The Time Machine, the protagonist finds a couple of constants during his early trips into the near future, including his friend Filby, and a shop near his laboratory that is featured in the time-travel montage whipping through a succession of window displays (later spoofed in the Discworld series, as described below). However, on his main excursion into the distant future he finds that everything has changed.
- In the Guy Pierce version of The Time Machine, he meets an AI librarian from the New York Public Library who is still there in the overgrown, recognizable ruins of New York thousands of years later.
- In Demolition Man, Spartan meets the helicopter pilot who air-dropped him into his final mission before becoming a Human Popsicle. Despite Spartan's difficulty adapting to the future, he never bothers to sit down with the old guy and pick his brain.
- Like Star Trek below, Star Wars gives the audience a few constants when telling a story in a new time period: The Phantom Menace has no Rebellion and no Empire, with a strange Republic and Trade Federation in their places; but we know it's the same 'verse because we see Obi-Wan from the beginning, and Artoo and Threepio, Yoda, and Tatooine later on.
- Both the film Field of Dreams and the novel Shoeless Joe, make note that baseball has still remained the same. In the movie, Terrance Mann even calls it this trope.
"The one constant through all the years, Ray, has been baseball. America has rolled by like an army of steamrollers. It has been erased like a blackboard, rebuilt and erased again. But baseball has marked the time."
- This is subverted in a scene in the comic [[Spider-Man I (Heart) Marvel: Web of Love]], where Captain America is seen watching a basketball game on TV with his Avengers pals and Mary Jane Watson-Parker. Confused by the rules added to the game since the 1940s and the resultant new tactics, he comments that at least baseball remained unchanged. Then Luke Cage brings up the designated hitter rule...
- Inverted in the James Garner film, Thirty Six Hours. The existence of something that should have vanished in a few days, a paper cut, is what convinces Maj. Pike, that he hasn't spent the last few years in a fugue state, as his German interrogators are trying to convince him he has in order to extract information from him.
- In Idiocracy a "Fuddrucker's" restaurant serves as the constant. After 500 years of increasing stupidity the name has gradually changed to "Buttfucker's." Oddly, it retains its status as a family restaurant, while Starbucks, H&R Block, and several other businesses have become brothels.
- In Demolition Man, every restaurant is a Taco Bell (or a Pizza Hut, for Europe).
Live Action TV
- In Ashes to Ashes which does not involve Time Travel Gene Hunt is Alex's constant because he was present in Sam Tyler's world in Life On Mars. This is of great importance to Alex as it could mean that she is inhabiting the same world as Sam Tyler, Thus disproving her original theory that she was in a coma. In the end, it is revealed that Alex is in purgatory.
- This fact is highlighted in 2×08 of Ashes to Ashes:
Martin Summers: "Look at us. Couple of desperate cases. Now you've lost your lifeline..."
Alex: *Mumbling in her sleep* "No."
Martin Summers: "...Your constant. Your Gene Hunt."
- This is explained in the series finale when it is discovered that Gene Hunt "created" the Universe/Purgatory after his death and "modelled" it to his own liking.
- Ray and Chris are also constants in both series, however Gene Hunt is the main constant to all characters because he is revealed to be a psychopomp for dead police officers.
- Nelson the Bartender from Life On Mars also appears at the end of Ashes to Ashes becuase he is a holy power and is accepting Alex, Shaz, Chris and Ray into heaven.
- A few minor characters (notably DCI Litton) from Life On Mars appear in Ashes to Ashes but because Alex never read of these characters from Sam Tyler's Notes, she can not ascertain if they are constants or figments. This is only revealed in the series finale.
- It's all very Solipsistic!
- Happens from time to time in Doctor Who due to its time-travel nature. A significant example comes during the last episode of the new Series 5, where events are put into place that makes Amy Pond the constant for the entire universe.
- The Trope Namer is an episode of LOST ("The Constant") in which Desmond is undergoing rapid Mental Time Travel between two times in his life and must find a Constant in the two times in order to avoid insanity and death. It's his girlfriend Penelope.
- On the same show, Daniel Faraday uses Desmond as his Constant.
- Although there's no Time Travel involved, McCoy appears in "Encounter at Farpoint", the first episode of Star Trek: The Next Generation, as a reminder that the two series take place in the same universe but different times.
- The same idea occurs with all the other series of Star Trek as well, with a character from a preceding series showing up in the first episode of the new series (Picard in Deep Space Nine, Quark in Voyager, Spock (and a reference to an Admiral Archer) in the reboot. Enterprise, due to taking place earliest in the continuity, used Zefram Cochrane from Star Trek: First Contact.
- In the two-part Next Generation episode "Time's Arrow", the long-lived Guinan is the link between times (along with Data's severed head).
- The Next Generation two-parter "Unification", created for an anniversary and featuring Spock, who is used to link the past and the present. Spock (specifically, Leonard Nimoy as Spock) is arguably this for the franchise as a whole, since he also appears in the 2009 reboot movie, where he actually serves to make it clear that the reboot is taking place in a different timeline, which is nevertheless at least related to the TOS one.
- The Guardian of Forever in the original series episode "The City on the Edge of Forever" claims to be this for almost all sentient history. "Since before your sun burned hot in space, I have awaited a question."
- Leene's Bell in Chrono Trigger and the Black Omen, later in the game (but previously chronologically). Also the Sun Cave, the Nu and, of course, Lavos.
- In Dark Cloud 2, there is almost always an overly obvious Constant: That baby Lapras-looking thing you saved helped to form the labs! That girl was the sage all along! etc.
- The video game series Legacy of Kain has the nine Pillars of Nosgoth, while they don't remain in a constant state (the ruination of the pillars is a major plot point) they remain as a constant on the landscape of the environment and a general marker for the time period. Along with the Pillars, Ariel's soul is present in every game but Blood Omen 2, and her state (bound to the Pillars) is constant, a reminder of Kain's decision not to sacrifice himself.
- The ruined tower in Sheratan in Baten Kaitos Origins serves as a constant for Sagi, who can eventually use it to travel back and forth in time due to housing a spirit who was alive back then.
- Happens several times to the immortal Kaim, in Lost Odyssey. A couple of incidents in the 'Dreams of a Thousand Years' section involve him meeting someone as a child, then crossing their paths again, 60, 70 or 80 years later, where they're old and dying, and he's still as young as ever. In the main game story, he also meets a wise old king - whom, as it turns out, he first met when he was a brash young prince, and taught a few things about combat, survival, and life in general.
- In Day Of The Tentacle, the same house exists for over 400 years, from the days of the Founding Fathers to the future where the tentacles have taken over the world, although it's much more metallic in the future. Also, many objects in the house can be found in more than one time period. This is often used by the main characters to affect one or more future time periods. For example, since only inanimate objects can be passed through the Chron-O-John, the only way to send a hamster to Laverne in the future is to put it in the freezer, which is still around 200 years from now. Apparently, no one has bothered to look inside in all this time. The time machine is still in the basement in the future (though it's broken and useless), and the laundry room doesn't change in the slightest - the coin-operated dryer Bernard sets running in the present is still going two hundred years later (he fed it a lot of change).
- The Legend of Zelda: Ocarina of Time and The Legend Of Zelda Oracle of Ages play with this trope a lot. It's possible the Deku tree is an example across the games, if the one in The Legend of Zelda: The Wind Waker is the same one in Ocarina. (More likely, it's the tree that grew out of the Deku Sprout, since the old one died.)
- Across both wildly divergent timelines in the Command & Conquer series, Tiberium and Red Alert, there is a corporation called Futuretech.
- In the Bioshock series, there is always a man, a lighthouse, and a city, no matter what universe.
- In Mass Effect 2, the Illusive Man invokes this trope to give the newly Back from the Dead Shepard a personal incentive to help Cerberus take down the Collectors, by having a larger and more advanced replica of the original Normandy built, convincing Joker and Dr Chakwas to join it's crew and sending Shepard to recruit some of their former squadmates for the mission. In doing so, he's able to keep Shepard's mind focused on the mission and not on the two years that have passed while they were clinically dead.
- King Bumi from Avatar: The Last Airbender. Aang knew him as a kid, got frozen in ice for 100 years, and then meets up with Bumi again as an old, crazy king. An episode is resolved by the revelation of this Constant.
- Katara acts as this in The Legend of Korra particularly for the audience. She's the only member of the original cast that we see until the 9th episode (save statues, of course).
- Similar to Avatar but across a much longer time period, there is an episode of Samurai Jack where Jack visits a temple he had been to in the past. Not only do the martial artist students practice the same traditions, but there is even a monk there, thousands and thousands of years old, that Jack met when he was there.
- Futurama has several Constants: the subterranean ruins of New York, the pizzeria where Fry used to work, the various heads of celebrities preserved in jars, and so on. The biggest one is probably Nibbler, who was responsible for Fry being frozen a thousand years earlier. And Fry's dog...who we'll skip over before we start to tear up.
- Applied Cryogenics somehow manages to survive for 1000 years without a power failure (or apocalyptic destruction), despite the "No Power Failures Since 1997" sign on the wall in the pilot episode, and that we see the world reduced to medieval levels twice during that time.
- There's a Shout-Out to The Planet Of The Apes in an episode where Fry, Bender, and the Professor travel forward in time to the year 10000. Fry, walking through the ruins of the city of New New York, sees a tilted, half-buried Statue of Liberty and laments "They blew it up! (pan to an identical statue of a gorilla) ... and then the apes blew up their society too!" (pan to another statue with a bird's head) "And then birds took over and ruined their society!" (pan to yet another statue) "And then cows ..." (pan again) "and ... I don't know ... is that a slug maybe? NOOOOOO!"
- In the Justice League episode "Hereafter", Superman is hurled forward some 30,000 years. He soon finds the immortal Vandal Savage as the sole survivor of the human race...who also happens to be responsible for the extinction of the rest of it. Savage feels understandably guilty about the whole thing, and sends Supes back to stop his past self.
- Demona in Gargoyles.
- Narbonic has one where Dave has to find a Constant, so he can get returned to the present. Getting slapped/punched by a girl works!
- In Homestuck, Dad is pretty much the same guy in both the original universe and the post-Scratch universe.
- As well, Caliborn's home is the troll's meteor and his planet is Earth, littered with Statues of Liberties.
- Jones (aka Wandering Eye) is a constant in Gunnerkrigg Court. In the flashbacks where the parents of the main protagonists are shown in their school days, Jones is there, appearing exactly as she does in the present. This (along with the inhuman speed and strength Jones had already demonstrated) led to fan speculation that Jones was a particularly humanoid robot, which author Tom Siddell shot down in comments without revealing any more than that. When Antimony finally gets the story out of her, it turns out that Jones has been around literally since the Earth was formed. Even she doesn't know what she really is.
- In Darwin's Soldiers: Pavlov's Checkmate, the main team is trapped in 1990, and needs to send a message to a teammate still in 2010. They do this by noticing a file cabinet that they recall seeing in 2010, and slipping a note inside it.
- In Fine Structure, Anne Poole is the Constant for over 20,000 years.