The folks at Kurzgesagt have done a few time travel videos now, but this one is notable for its concise, intuitive explanation and visualization of our constant speed through spacetime (special relativity).
Everything in our universe moves at the speed of light through four dimensional spacetime. Your speed through spacetime is the sum of your separate speeds through time and space. It is impossible for you to stay still. Even if you are not moving through space dimensions, you are moving through the time dimension, blasting face first into the future.
You can slow down in the time dimension, by moving faster through the space dimensions but in total, you will always move at the speed of light through spacetime.
And you can “trade” moving through space for moving through time: “Move faster through space, go slower in time. Move slower through space, go faster in time.” Or as a commenter put it:
Your speed is constant. So the faster you move through the space dimensions, the slower you move through the time dimension, and vice versa.
Not sure this textual explanation makes as much sense as the visualization in the video, so maybe just watch that? Oh, and check out the sources for the video.
For Ars Technica, science writer Jennifer Ouellette and theoretical physicist Sean Carroll review time travel used in 20 popular movies, ranging from The Terminator to Bill and Ted’s Excellent Adventure to Interstellar. Each movie is rated on scientific accuracy and how entertaining the use of time travel is. Here’s part of their review of Superman (1978).
Our standards are admittedly lax when it comes to the physical mechanism by which cinematic heroes journey through time, but “flying really fast around the Earth so that it reverses the direction of its rotation and sends it back to a previous moment” is such thoroughgoing lunacy that one must almost pause in admiration. Then we return to our senses and ask, “Why does Superman’s flight have any effect on the rotation of the Earth? And what does that rotation have to do with the direction of time? Do I get younger if I start twirling counterclockwise?” No, dear reader, you do not. Indeed, by the rules handed down by Einstein, Superman’s near-speed-of-light journey would actually send him into the future, not into the past.
To its dubious credit, Superman pioneers two different flaws that will frequently recur in movies to come. First, time travel is portrayed as a miraculous cure-all, which is then never used again. Superman essentially goes back in time to save his girlfriend. This is admirable, but aren’t there other, more historically significant global disasters that could be averted by the same strategy? This is a narrative problem, not a scientific or logical one, but it rankles.
Then, of course, there is the flaw that almost always accompanies stories in which the past gets changed by time-travelers: Where did those time-travelers come from? We, the viewers, see a sequence of events that seems to make sense if we don’t think too hard. Lois Lane dies, Superman gets upset, he travels back in time, stops the events that led to Lois dying, and we live happily ever after. But at the end of this sequence, Superman still has the memory of Lois dying the first time around. Yet because he changed history, that event he remembers never happened. Lois certainly doesn’t remember it. How does he?
Kurzgesagt’s latest video on the paradox of time is a bit more of a brain-bender than their usual videos. From the accompanying sources document:
This video summarizes in a narrative format two well-known theories about time: the so-called “block universe” and the “growing block”.
The block universe is an old theory of time which appears to be an unavoidable consequence of Einstein’s theory of special relativity. In philosophical contexts, basically the same idea is known as “eternalism”. Simplified, this theory posits that, although not apparent to our human perception, both the past and the future exist in the same way as the present does, and are therefore as real as the present is: The past still exists and the future exists already. As a consequence, time doesn’t “flow” (even if it looks so to us) and things in the universe don’t “happen” - the universe just “is”, hence the name “block universe”.
But then: “Quantum stuff is ruining everything again.” And so we have the growing block theory:
The Evolving/Growing Block: A relatively new alternative to the classical block universe theory, which asserts that the past may still exist but the present doesn’t yet, and all that in a way that is still compatible with Einstein’s relativity.
And there are still other theories about how time works:
Some scientists think that the idea of “now” only makes sense near you, but not in the universe as a whole. Others think that time itself doesn’t even exist — that the whole concept is an illusion of our human mind. And others think that time does exist, but that it’s not a fundamental feature of the universe. Rather, time may be something that emerges from a deeper level of reality, just like heat emerges from the motion of individual molecules or life emerges from the interactions of lifeless proteins.
It’s a pleasure to be here in Jason’s esteemed garden of links and digressions, celebrating 20 years since we created Snarkmarket. In keeping with our host’s splendid curatorial style, most of what I’ll post here are not little bloggy essays like this one. But there’s one thing I especially wanted to ask this crowd about.
Few people would ever have known about Snarkmarket if not for the short video Robin and I made, EPIC 2014 (and then, a year later, 2015), that went viral in an era of the internet in which virality was difficult. To make a video viral in 2004 meant people mirroring a file on their private servers, linking to it on their blogs, and emailing links to friends and colleagues. But the video itself imagined that friction as a thing of the past. YouTube didn’t yet exist, but we’d guessed that it or something like it was coming. A world where sharing was difficult had already begun to feel obsolete, even while we were still living in it.
I’ve come to find it useful to imagine parts of the world around me in past tense. There seem to be many things these days that we’ve committed to ending or know we can’t sustain, even though they’ll probably be omnipresent for years to come. Many stem from our changing climate and growing sense of the toxic effects of constantly gassing the air. In a few years, for example, most of the new cars sold in California won’t have gas engines anymore, by state decree. But that’s not all of it. Nowadays almost every time I find myself in a retail store that’s not a pharmacy, I get an anachronistic jolt. I don’t know if I’ll ever think about an office commute again the way I have for decades of my life.
The most obvious function of this exercise is to help me consider my own behaviors, wants, and habits in a different light. I hope to someday laugh at the fact that we once found it convenient to encase individual slices of cheese in plastic.
As a habit of mind, it’s also a way of grounding me more deeply in the world I still inhabit. It helps me savor the things I expect to grieve, and mark the things I hope to outlive. When I’m sick, I try to take mental notes for my future selves, reminding me not to take for granted the mundane luxury of breathing easy.
But I think this should be more of a collective exercise. We know that we’re seeing the end of an era and the beginning of another. We’ve pledged ourselves to this, in fact. So what should we look at as having begun to end? When we look back on this moment 20 years hence, what will we strain to remember? What will seem as distant to us as that world two short decades ago when making a video go viral required the distributed muscle of a network of human beings?
In this short film, a man stuck in a 24-hour time loop enlists his firefighter brother to stop a fire that will cause many deaths. But their efforts repeatedly fail to change the ultimate outcome of the day and they’re left with what really mattered all along.
The English language, for better or worse, is constantly shifting and changing, with dozens of new and useful words being added to our collective vocabulary each year. With Merriam-Webster’s Time Traveler tool, you can browse what new words were first used in years dating all the way back to 1500 (and even earlier). The obvious thing is to look up your birth year, so I did that and then poked around for some other interesting years.
This is extremely inexpensive time travel. Almost every year is a gold mine (1605!) of terms that are seemingly out of time, either too early or too late. Careful, you might lose several hours to this. (thx, megan)
Comics fans and the internet at large have been enchanted by the new author of the classic Nancy comic, Olivia Jaimes. This comic from Sunday shows why:
If you check out the thread for the comic on Twitter, there are several instances of comics that mess with time and space like this, but the final panel by Jaimes is particularly strong. I definitely Laughed Out Loud.
Update: Delta’s current onboard safety video takes place within the illustrated world of the seat-back safety card and contains several instances of fourth-wall breaking.
Are wormholes science or just science fiction? As this video by Kurzgesagt shows, they’re actually a little bit of both. Einstein and string theory both posit that these “short cuts” through spacetime could exist, but finding or building a stable wormhole, a la Star Trek, is another matter altogether.
In the description of the video, they link to a pair of papers published by Michael Morris and Kip Thorne in the late 80s: Wormholes, Time Machines, and the Weak Energy Condition and Wormholes in spacetime and their use for interstellar travel: A tool for teaching general relativity. For a high school physics class, I gave a presentation on wormholes & time travel and I’m pretty sure I used at least one of those papers as a reference. The presentation also included a clip of Bill & Ted’s Excellent Adventure. The teacher gave me a B+ — he felt the presentation was excellent (*guitar riff*) but that I had, in spite of the movie clip, “lost most of the other students” and should have chosen a more suitable topic.
Stephen Hawking, who uncovered the mysteries of black holes and with A Brief History of Time did more than anyone to popularize science since the late Carl Sagan, has died at his home in Cambridge at age 76. From an obituary in The Guardian:
Hawking once estimated he worked only 1,000 hours during his three undergraduate years at Oxford. In his finals, he came borderline between a first- and second-class degree. Convinced that he was seen as a difficult student, he told his viva examiners that if they gave him a first he would move to Cambridge to pursue his PhD. Award a second and he threatened to stay. They opted for a first.
Those who live in the shadow of death are often those who live most. For Hawking, the early diagnosis of his terminal disease, and witnessing the death from leukaemia of a boy he knew in hospital, ignited a fresh sense of purpose. “Although there was a cloud hanging over my future, I found, to my surprise, that I was enjoying life in the present more than before. I began to make progress with my research,” he once said. Embarking on his career in earnest, he declared: “My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all.”
He went on to become his generation’s leader in exploring gravity and the properties of black holes, the bottomless gravitational pits so deep and dense that not even light can escape them.
That work led to a turning point in modern physics, playing itself out in the closing months of 1973 on the walls of his brain when Dr. Hawking set out to apply quantum theory, the weird laws that govern subatomic reality, to black holes. In a long and daunting calculation, Dr. Hawking discovered to his befuddlement that black holes — those mythological avatars of cosmic doom — were not really black at all. In fact, he found, they would eventually fizzle, leaking radiation and particles, and finally explode and disappear over the eons.
Nobody, including Dr. Hawking, believed it at first — that particles could be coming out of a black hole. “I wasn’t looking for them at all,” he recalled in an interview in 1978. “I merely tripped over them. I was rather annoyed.”
That calculation, in a thesis published in 1974 in the journal Nature under the title “Black Hole Explosions?,” is hailed by scientists as the first great landmark in the struggle to find a single theory of nature — to connect gravity and quantum mechanics, those warring descriptions of the large and the small, to explain a universe that seems stranger than anybody had thought.
The discovery of Hawking radiation, as it is known, turned black holes upside down. It transformed them from destroyers to creators — or at least to recyclers — and wrenched the dream of a final theory in a strange, new direction.
“You can ask what will happen to someone who jumps into a black hole,” Dr. Hawking said in an interview in 1978. “I certainly don’t think he will survive it.
“On the other hand,” he added, “if we send someone off to jump into a black hole, neither he nor his constituent atoms will come back, but his mass energy will come back. Maybe that applies to the whole universe.”
Dennis W. Sciama, a cosmologist and Dr. Hawking’s thesis adviser at Cambridge, called Hawking’s thesis in Nature “the most beautiful paper in the history of physics.”
Following his work in this area, Hawking established a number of important results about black holes, such as an argument for its event horizon (its bounding surface) having to have the topology of a sphere. In collaboration with Carter and James Bardeen, in work published in 1973, he established some remarkable analogies between the behaviour of black holes and the basic laws of thermodynamics, where the horizon’s surface area and its surface gravity were shown to be analogous, respectively, to the thermodynamic quantities of entropy and temperature. It would be fair to say that in his highly active period leading up to this work, Hawking’s research in classical general relativity was the best anywhere in the world at that time.
Drawing from David Wittenberg’s book, Time Travel: The Popular Philosophy of Narrative, as a guide, Evan Puschak goes in search of the origins of time travel in fiction. Along the way, he connects Charles Darwin’s work on evolution to the largely forgotten genre of utopian romance novels to the depiction of time travel in modern sci-fi.
P.S. While I was in France, I met up with Evan for lunch (we happened to be in Paris at the same time). We’d never met before, and it was really strange hearing the voice of one of my favorite YouTube channels coming out of an actual person.
Using a number of hand-drawn diagrams, minutephysics goes over the various types of time travel featured in books and movies like Primer, Harry Potter, Back to the Future, and Looper. The video covers free will, do-overs, alternate timelines, multiple selves, time machines within time machines, and many other things.
Entanglement involves putting objects in the peculiar limbo of quantum superposition, in which an object’s quantum properties occupy multiple states at once: like Schrodinger’s cat, dead and alive at the same time. Then those quantum states are shared among multiple objects. Physicists have entangled particles such as electrons and photons, as well as larger objects such as superconducting electric circuits.
Theoretically, even if entangled objects are separated, their precarious quantum states should remain linked until one of them is measured or disturbed. That measurement instantly determines the state of the other object, no matter how far away. The idea is so counterintuitive that Albert Einstein mocked it as “spooky action at a distance.”
What’s weird to me is that all the articles I read about this touted that this happened in space, that an ultra-secure communications network was possible, or that we could build a quantum computer in space. Instantaneous communication over a distance of hundreds of miles is barely mentioned. Right now, it takes about 42 minutes for a round-trip communication between the Earth and Mars (and ~84 minutes for Jupiter). What if, when humans decide to settle on Mars, we could send a trillion trillion quantum entangled particles along with the homesteaders that could then be used to communicate in real time with people on Earth? I mean, how amazing would that be?
Update: Well, the simple reason why these articles don’t mention instantaneous communication at distance is that you can’t do it, even with quantum entanglement.
This is one of the most confusing things about quantum physics: entanglement can be used to gain information about a component of a system when you know the full state and make a measurement of the other component(s), but not to create-and-send information from one part of an entangled system to the other. As clever of an idea as this is, Olivier, there’s still no faster-than-light communication.
In his newest video, Evan Puschak talks about Arrival, calling it “a response to bad movies”. Arrival was perhaps my favorite film of 2016, and I agree with him about how well-made this film is. There’s a top-to-bottom attention to craft on display, from how it looks to how it was cast (Amy Adams was the absolute perfect choice for the lead) to the integration of the theme with story to how expertly it was adapted from Ted Chiang’s Story of Your Life. The whole thing’s tight as a drum. If you happened to miss it, don’t watch this video (it gives the whole thing away) and go watch it instead…it’s available to rent/buy on Amazon.
Looking back through the archives, I’m realizing I never did a post about Arrival even though I collected some links about it. So, linkdump time!
Update: The director of photography for Arrival was Bradford Young, who shot Selma and is currently working on the Han Solo movie for Disney. Young did an interview with No Film School just before Arrival came out.
I’m from the South, so quilts are a big part of telling our story. Quilting is ancient, but in the South it’s a very particular translation of idea, time, and space. In my own practice as an image maker, I slowly began to be less concerned with precision and more concerned with feeling.
Quiltmakers are rigorous, but they’re a mixed media format. I think filmmaking should be a mixed media format. I’m just really honoring what quiltmakers do, which is tell a story by using varying texture within a specific framework to communicate an idea. For me, with digital technology, lenses do that the best. The chips don’t do it now-digital film stock is basically all captured the same, but the lenses are how you give the image its textural quality.
What if the future is as real as the past? Physicists have been suggesting as much since Einstein. It’s all just the space-time continuum. “So in the future, the sister of the past,” thinks young Stephen Dedalus in Ulysses, “I may see myself as I sit here now but by reflection from that which then I shall be.” Twisty! What if you received knowledge of your own tragic future-as a gift, or perhaps a curse? What if your all-too-vivid sensation of free will is merely an illusion? These are the roads down which Chiang’s story leads us. When I first read it, I meant to discuss it in the book I was writing about time travel, but I could never manage that. It’s not a time-travel story in any literal sense. It’s a remarkable work of imagination, original and cerebral, and, I would have thought, unfilmable. I was wrong.
Christopher was 15 or 16 when he worked on the film. His LinkedIn profile states that he’s been a programmer for Wolfram (the company) since he was 13 and that in addition to his work on Arrival, he “implemented the primary cryptography functions in Mathematica”.↩
Phil Edwards talks to James Gleick about his new book, Time Travel: A History, and of course the subject of killing Baby Hitler comes up. Turns out, the idea of using time travel to kill Adolf Hitler was first used by writer Ralph Milne Farley in 1941, before the US ever entered World War II or before the world learned the horrifying scope of the Holocaust.
I’m currently reading Gleick’s book and the most surprising thing so far is how recently time travel was invented…it’s only about 120 years old. The idea of progress was not really evident to people before the pace of technology and the importance of history became apparent in the 19th century. Progress made time travel relevant…without it, people couldn’t imagine going back in time to see how far they’d come or forward in time to see how much they’d progress.
In an episode of Doctor Who from 2010, the Doctor and his companion Amy take Vincent van Gogh, who was not a commercially successful artist in his own lifetime, to the Musée d’Orsay to see an entire room filled with his paintings. The resulting scene is unexpectedly touching.
[Spoilers!] This season, Game of Thrones is experimenting with time travel. A few years ago, Harrison Densmore created a chart showing the three kinds of time travel that happens in movies: fixed timeline (as in 12 Monkeys), dynamic timeline (as in Back to the Future), and multiverse (as in Terminator 2). So which kind of time travel is happening in Game of Thrones?
P.S. In addition to the extensive spoilers about what’s already happened on the show, the latter moments of the video also offers some fan theories about what might happen on the show in the future. If that sort of thing bothers you, maybe stop watching around the 4:05 mark.
James Gleick, author of The Information, Chaos, and Genius, is coming out with a new book this fall called Time Travel. William Gibson has given it his thumbs up. Really excited for this one (it comes out on my birthday!) and curious to see how liberally he treats his subject…for instance, cameras are time machines.
In the future, when time travel is a totally normal thing to do, people will use it to do stuff like tell their 10-year-old selves to learn the guitar so their adult selves can impress women.
Suppose you had a time machine you that you solely wanted to use for financial gain. You can bring one item from the present back to any point in the past to exchange for another item that people of that time would consider of equal value, then bring that new item back to the present. To what time period would you go, and what items would you choose to maximize your time-travel arbitrage?
Cowen notes some difficulty with an obvious approach:
The obvious answer encounters some difficulties upon reflection. Let’s say I brought gold back in time and walked into the studio of Velazquez, or some other famous painter, and tried to buy a picture for later resale in the present. At least some painters would recognize and accept the gold, and gold is highly valuable and easy enough to carry around. Some painters might want the gold weighed and assayed, but even there the deal would go fine.
The problem is establishing clear title to the painting, once you got back home. It wouldn’t turn up on any register as stolen, but still you would spend a lot of time talking to the FBI and Interpol. The IRS would want to know whether this was a long-term or short-term capital gain, and you couldn’t just cite Einstein back to them. They also would think you must have had a lot of unreported back income.
So establishing present ownership of a past item is an issue…as is authentication via carbon dating. I don’t have a specific scheme in mind, but I would think any general approach would also need to minimize the butterfly effect of your trade so that, for example, your existence in the present is not disrupted. So you can’t trade Leonardo an iPhone 6 for the Mona Lisa. But maybe you could trade $1 for a winning ticket for last week’s $300 million lottery jackpot…or would the numbers change somehow because of your visit? What if you bought 100,000 shares of Apple stock in 2003? How would that action effect the present? What is a large enough action to make you rich but with a small enough effect to keep the present otherwise unchanged? Since I didn’t see any super-compelling solutions in the comments at MR, I’m gonna open the comments here…I know someone has been thinking about this extensively or has a link to a good discussion elsewhere. Please stay on topic, mmm’kay?
In 1997, Max-Hervé George’s father bought a unique policy from a French insurance company that functions like Grays Sports Almanac from Back to the Future II, only for financial markets. The policy allows George to invest in investment funds offered by the insurance company at prices up to a week old, essentially traveling back in time with knowledge of which investments will increase in price the most.
For instance, he might have his money in an Aviva fund invested in the French stock market. Lets say the Nikkei 225 rises 5 per cent during the week. He’ll tell Aviva to move his investments into its Japanese fund, at the price before the market moved.
At last report, in 2007, George’s investments were worth €1.4 million and growing at a rate of 68.6% per year. Assuming that rate holds and he continues investing his entire allocation optimally, George will be a billionaire in five years, would be able to buy the insurance company in question by 2025, and be worth a whopping €234 billion by 2030.
Here, three implementations of Internet searches for time travelers are described, all seeking a prescient mention of information not previously available. The first search covered prescient content placed on the Internet, highlighted by a comprehensive search for specific terms in tweets on Twitter. The second search examined prescient inquiries submitted to a search engine, highlighted by a comprehensive search for specific search terms submitted to a popular astronomy web site. The third search involved a request for a direct Internet communication, either by email or tweet, pre-dating to the time of the inquiry. Given practical verifiability concerns, only time travelers from the future were investigated.
Steven Hawking came up with a simple and clever way of seeing if time travel is possible. On June 28, 2009, he threw a party for time travellers from the future…but didn’t advertise it until after the party was already over.
In an effort to improve the chances of the party invite being noticed by future generations, Peter Dean, working with approval from Hawking, has made this gorgeous hand-printed poster of the party invitation:
Looks like Syfy has ordered a “cast-contingent” hour-long pilot for an adaptation of Terry Gilliam’s Twelve Monkeys, with an eye to make it into a proper TV series. One of the producers of Gilliam’s 1995 film is on board, and Terry Matalas and Travis Fickett, who both worked on Terra Nova and Nikita, wrote it. The model here is Battlestar Galactica: a movie reboot that could be a mini-series that could be multiple seasons.
Syfy’s Mark Stern talked about it with The Hollywood Reporter, back when the pilot was 90 minutes long and still waiting to be approved for production while the network and producers figured out what the whole series would be about:
It’s a return to our roots in terms of science fiction: cool, interesting push-the-genre science fiction. Some we’re looking at doing straight to series, because you really want to give them the flexibility and do a closed-ended, arced run. Some of them are going to be traditional pilots, and then we’ll decide and they may be a bit more episodic.
Given the time-travel theme, the fact that the source material (both Twelve Monkeys and La Jetée) are well-known, and the way TV’s changed over the last ten years with jigsaw-puzzle series like LOST and the revived Arrested Development, I’m curious to see if the showrunners might mess around with the timelines a bit, jumping around, giving the audience previews of things the story doesn’t explain right away, and generally making Doctor Who look like it’s for precocious kids (which, really, it kinda is).
ES: In your real life. If you, Michel Gondry, found a time machine and could go anywhere, to any period in history, where would you take it?
MG: I would travel back a few years ago and fix some screw-up I did.
ES: A personal or professional screw-up?
MG: In my personal life.
ES: Can you be more specific?
MG: I would come back and say yes to a girl. That’s all. Actually, I find the whole idea of traveling back in time to be profoundly depressing.
ES: Really? Why so?
MG: Because I know the future. Living in the past, it would feel weird to know what’s going to happen next. You couldn’t escape it. That future’s already in your head. You know it doesn’t get better.
ES: You’d rather not know about the future?
MG: The future is about hope. If you travel from the present to the past, you don’t have that hope anymore. You know how everything turns out.
ES: There are no surprises.
MG: No surprises, exactly! To me, that just sounds so… depressing.
According to sources familiar with the experiment, the 60 nanoseconds discrepancy appears to come from a bad connection between a fiber optic cable that connects to the GPS receiver used to correct the timing of the neutrinos’ flight and an electronic card in a computer. After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed.
Neutrinos? More like Nintendo…they forgot to blow in the cartridge. (via @tcarmody)
Mesmerizing Zapruder-esque footage that seems to show a woman talking on a mobile phone at the 1928 premiere of a Charlie Chaplin film at Mann’s Chinese Theatre.
According to this guy, the simplest explanation is that the woman is a time traveller. Stick that in your Occam’s razor and shave it! (via geekologie)
Stay Connected