Fantasy Science Pt. 1: Wormholes In DEJA VU, STARGATE & Real Life
In this first part of Fantasy Science, our resident physicist Radha Pyari Sandhir explains wormholes and discusses how they are portrayed in film, and explains what the real life science behind them is.
Entanglement. Time travel. Wormholes. Have you heard terms like these flying around the science fiction sections of the film world? Have you ever wondered just how accurately these films portray real science? Well, my friends, this is your lucky day: my all new series Fantasy Science & Coffee aims to bridge the gap between science and science fiction in films and occasionally popular culture. My hope is to explain things in a fun way – like we’re chatting over coffee.
You may be thinking: who is this person, why does she think she can explain science, and why the heck would I want to have coffee with her? Well, I’m Radha, a researcher in India, currently pursuing a PhD in theoretical quantum physics. I quite like hot beverages. I’ll also pay.
In this very first part of the series, I’m going to look at how wormholes are presented in the films Deja Vu (2006) and Stargate (1994), and compare them to what we expect in the real world.
Think about how much you hate traffic. Or airplane food. Or your cat screaming bloody murder for the seemingly aeons it takes to drive to the vet, I mean come on, Blade, you should understand by now that I’m not trying to kill you!
Ahem. I digress. Think about those things, and just how fantastic it would be if you could simply step through a doorway and reach your destination without all the hassle of travel. You could cover vast distances, even galactic distances, in no time.
If this sounds like science fiction to you, then you are partially correct. Doorways connecting different points of space no matter what the distance is between them are actually possible – in theory. They are more accurately visualised as tunnels through space, and are viable solutions to Einstein’s equations of General Relativity.
In 1916, physicists Einstein and Nathan Rosen theorised a sort of bridge between two points in not just space but the fabric of spacetime, which we now, quite deservedly, call an “Einstein-Rosen Bridge”. The more casual term for this bridge is ‘wormhole’.
While wormholes haven’t actually been detected in our universe, they are romantic story devices heavily used across different forms of science fiction. Two films with plots that solely manifest from the concept of wormholes are Deja Vu (2006) and Stargate (1994).
Wormholes in Deja Vu
In Deja Vu, a devastating criminal act is investigated with the help of a top secret research facility that has successfully bent the fabric of spacetime to connect the present with four days prior. With the help of this wormhole, they put the past under surveillance to find the culprit behind the terrorist act.
In short, the Deja Vu wormhole is a successful bridge in both space and time. If we had the ability to create these types of wormholes, not only would you be able to take your cat to the vet hassle-free, you could visit the clinic yesterday.
The wormhole is consistently left open, and requires an immense amount of power. The scientists involved joke that one of their experiments had caused a notorious blackout for half the northeast of the North American continent, triggering a blame game between Canada and Michigan.
Here’s a clip in which the protagonist, Doug, unaware that he is looking through a wormhole for the surveillance, suspected that there was more than meets the eye. He demands explanations from the scientists, and they try to explain the physics to him.
In this clip, the scientists claim that no living being can be sent through the wormhole, because the electromagnetic field would annihilate any fluctuating body signals like heartbeat, brain waves, and so on. Later in the film, they decide to send Doug back in time through the wormhole to an emergency room. He arrives pretty much dead, but is then resuscitated.
Wormholes in Stargate
In the 1994 film Stargate and its subsequent TV series, an ancient race built circular gates through which people can traverse the universe in very short periods of time by establishing wormholes.
There are a few ways in which the wormholes in Stargate differ from those in Deja Vu:
- An immense amount of power is required to generate the wormholes, similar to that in Deja Vu. However, the power is “literally astronomical” as quoted in the first episode of Stargate SG-1.
- They are not completely stable, that is, they can’t be left open for very long periods of time.
- They can only be used for one-way travel. The loophole is that any probe that goes through can send a signal back through the wormhole, but cannot physically return. (If any of the tv series depicts a two-way traversable wormhole, I am not aware of it, as I’m just starting to watch them!)
- Living beings can successfully walk through the Stargates. They might feel a tad nauseated and regret that large stack of maple syrup infused pancakes for breakfast, but they are otherwise unscathed.
- The wormholes themselves are depicted as a fluidic shiny silver goo, and as a physicist, I must say I have a bias towards anything fluidic, silver, and shiny. Sorry, not sorry.
Wormholes in Real Life
Unfortunately, in real life, wormholes aren’t as grand or romantic. We actually haven’t detected any as far as I know; all we’ve done is theorise about them with the help of math and General Relativity.
Moreover, the math points to actual wormholes being super duper unstable, so it remains to be seen whether we can actually use one for travel at all. According to Ask a Spaceman, simply breathing would destabilise a wormhole! In 1988, Michael Morris and Kip Thorne came up with nine rules for a traversable wormhole in their paper Wormholes in spacetime and their use for interstellar travel: A tool for teaching general relativity. It’s an intense, beautiful, if highly mathematical, read.
The rules are:
- The wormhole shouldn’t change with time, that is, it should remain static. This was actually an assumption that they made to make the math easier, but it makes sense: something that changes over time unpredictably is unreliable – sort of like a tornado that alters its course without warning. A wormhole that changes its destination in space and time every second would be a nightmare. Imagine entering such a wormhole: you’d embark on a cool expedition to the planet Saturn but might end up in your mother-in-law’s kitchen instead. On her birthday. Yikes.
- The wormhole should obey the laws of General Relativity. Fairly straightforward, to be honest. If we can’t assume that the laws of physics as we know them hold, then what can we assume?
- The wormhole must have a throat that connects two flat regions of spacetime, essentially looking like the figure above. (Those of you more familiar with spacetime might have alarm bells ringing at the word ‘flat’ but what Morris and Thorne meant was asymptotically flat.)
- Before getting into this rule, let’s talk briefly about what a black hole is. It’s a point in space caused by a star that has collapsed inward. It has such an insanely huge mass that it warps spacetime around it, pulling everything nearby into its black belly. Even light. It’s like a galactic sink. Now, here’s rule number four: There should be no horizons on either side of the wormhole. In this case, a horizon is not that nice beautiful thing that makes sunsets look pretty, it’s an area around a black hole within which you can’t escape no matter how hard you try. Basically, if you step into a horizon, you’re screwed. There’s a slight loophole that we’ll talk about in a bit, though.
- Gravitational forces should be small within the wormhole. You don’t want a wormhole traveller to get spaghettified. Yes, that’s an actual thing in physics.
- Traversing the wormhole shouldn’t take a lot of time. Morris and Thorne say it should be less than a year, but heck, I wouldn’t want to set up an overnight camp in a spacetime tunnel that I don’t completely understand. I’m good with a few minutes.
- The wormhole should be made with things that exist in our universe.
- The wormhole should be stable enough to travel through.
- We should be able to assemble the wormhole within a reasonable time frame and with reasonable mass, read less than the age and mass of the universe, respectively. Otherwise there’s no point in building it, right?
Now that we have the rules down pat, it should be fairly easy to construct a wormhole, correct? Unfortunately, the answer is “no”. The most troubling of these rules is number seven: the requirement that the wormhole be built with stuff that exists within our universe. From what we understand now, though, it looks like wormholes can only be assembled with something called negative mass, and we don’t have any of that lying around here (that we know of). Note: negative mass is not antimatter. Going into detail is currently beyond the scope of this article, but I’ve linked a couple of interesting articles below.
Let’s take a step back for a moment and look at rule number four again. The horizon around a black hole is also referred to as an event horizon because all possible events within it result in the same outcome: you being sucked in by the singularity that is the black hole. It’s essentially an invisible shell around the black hole that acts as a threshold. If you step past the threshold, you are at the point of no return, and you can never, ever escape.
There is, however, a loophole to rule four. If one end of the wormhole has a horizon, and the other does not, then it essentially becomes a one-way traversable wormhole, which is still valid as a solution to the General Relativity equations. It can be visualised as a bridge between a black hole and a white hole. You can never escape a black hole, and you can never enter a white hole. Note that white holes have as yet to be found in nature, as far as I know.
Fun fact: the Stargate’s beautiful silver goo that you step through is referred to in the series as an ‘event horizon’. Which is likely why the wormholes are just one-way traversable. Such a subtle but beautiful detail on behalf of the writers! This is probably why I prefer Stargate wormholes over Deja Vu wormholes. It doesn’t have anything to do with how pretty and fluidic it looks at all, I swear.
Now, tell me, which of the wormhole styles in these two films do you prefer?
More to Explore
Space.com (2017): Could Wormholes Really Work? Probably Not
Quanta Magazine (2017): Newfound Wormhole Allows Information to Escape Black Holes
Medium (2014): Cosmologists Prove Negative Mass Can Exist In Our Universe
Teleportation Through the Wormhole by Leonard Susskind, Ying Zhao (2017)
Wormholes in spacetime and their use for interstellar travel: A tool for teaching general relativity [PDF] by Michael S. Morris and Kip S. Thorne, American Journal of Physics (1988)
Wormholes, Time Machines, and the Weak Energy Condition [PDF] by Michael S. Morris, Kip S. Thorne, and Ulvi Yurtsever Phys Rev Lett (1988)
An interesting side-note: The focus of this article is on traversable wormholes. However, there’s been some really fascinating work on entangled black holes and how they may lead to non-traversable wormholes, to take care of the information paradox. If interested, I encourage you to look up Leonard Susskind’s lectures on ER=EPR.
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