Ever so slightly disappointed at the complete lack of mention of Steins;Gate (http://en.wikipedia.org/wiki/Steins;Gate) in the paper. Interesting read all the same :)
Quite interesting with the methods used, alas the conclusion:
> Unfortunately, as of this writing, no prescient tweets or emails were received. Given the additional
exposure that the public listing of this manuscript gains, we will continue to search, on occasion, for
active tweets and emails involving potential time travel.
> Although these negative results do not disprove time travel, given the great reach of the Internet, this search is perhaps the most comprehensive to date.
Isn't the issue here that they are describing the methods through which they are trying to determine time travel. In effect, telling anyone in the future exactly what not to do.
Let's also assume that somebody had a reason to travel into the past, say to kill Hitler. Our timeline would record that an Austrian artist was murdered in the 1920s. We would not consider this historically significant.
I think time travel is inherently very difficult to detect. Even if a time traveller 'dropped' tech. This tech would be recoverable by popping back in time and recovering it.
Actually, as hardly anyone remembers Leopold II maybe he is the ideal target.... :-|
[NB I eventually remembered that I'm against the death penalty - so what I am actually in favor of is apprehending the relevant individuals and bringing them back to face trial by the appropriate authorities. Although I admit there would be a distinct temptation to do a Cheradenine Zakalwe with Vasili Blokhin:
Killing Stalin without killing Hitler might not be the best idea, considering the vital role Russia played in the defeat of the nazis. And maybe Leopold II gets overlooked by time travelers exactly because they also don't remember him.
(Good of you to mention Leopold II, though. Also note Henry Morton Stanley's role in that despicable piece of genocide.)
Actually, the H man and those guys don't make the cut. The ones deserving of time-travel assassination have already been dealt with. Hence we don't know of them.
Exactly. If we are going to hypothesize about time travelers then we have to accept that any significant reason to time travel has already happened. Futhermore it has happened more times than we are aware of to create our specific timeline.
7000 personally executed over 28 consecutive nights, through a shot in the base of the skull while wearing a leather apron, gloves and hood, 300 a night for 10 hours each night, one every 3 minutes?
That's some character...
It takes a certain kind of monster to order the execution of 7000 officer prisoners of war. It takes another kind to carry it out personally with a collection of pistols brought in especially for the job.
I can recommend (if that is the correct term) the book "Stalin: The Court of the Red Tsar" for a chilling description of the leadership of the Soviet Union from the early 30s until Stalin's death:
Agreed! It is next to impossible to understand soviet Russia without knowing what is covered in that book. It completely changed my view of the whole Bolshevik experiment, especially Stalin's role. What had been a mystery to me became much clearer.
Would it not be a much better idea to kill Columbus, and prevent the 'discovery' of the Americas, thereby saving the population of nearly two whole continents? Can't be much more efficient with your time travel than that I reckon.
edit:
Just read the interesting link you posted to 20th centuries bloodiest tyrants. I wonder why Johnson and Nixon are not in the third list, bloody tyrants who killed over 400.000 innocent civilians in the Vietnam war using horrible chemical warfare.
Columbus was a particularly unsavoury individual whose instinct was to sell the Taino natives he encountered as slaves, but it is difficult to imagine a scenario where the inevitable large scale contact between the Old and the New Worlds would not have resulted in calamitous declines in the native population of the Americas who had no resistance to smallpox and other Old World pathogens, no matter the nature of the intial contact. Even without Columbus, it would have been a matter of time before the Europeans found out about the Americas.
Because of Columbus I and most of Latin Americans are born, most of us are a mix of European and Native Americans. If all of that population was really killed, there would be just white people in the spanish and portuguese territories.
My point was that the population was not exterminated in this side of America, the proof is us (Latin Americans), for example Mexico with 90% of its population being "mestizo" (european/native american) with variations of 70%/30% 50%/50% 30%/70%
Have you read "Pastwatch: The Redemption of Christopher Columbus" by Orson Scott Card? It get's a little weirdly preachy, but the idea that Columbus really is the fulcrum about which the fate of the Americas tips, and that if you could go back and get him to think of the locals as actual people and not savages, things could work out pretty good.
you are assuming time travelers change history, but it's different if you subscribe to the idea that you can't change past because in fact you did not change the past.
Then you can detect people saying stuff about the future, or possibly attempting to kill hitler while failing miserably.
> Let's also assume that somebody had a reason to travel into the past, say to kill Hitler. Our timeline would record that an Austrian artist was murdered in the 1920s.
This would prevent World War 2 and the associated advances in technology, possibly including those leading to the time travel being possible in the first place.
You could also imagine the converse, where someone from the future brings back all scientific knowledge, thus reducing the time it takes scientists of the past to invent time travel, which in turn leads to that person bringing back all scientific knowledge sooner, perpetuating onwards until massive amounts of knowledge are acquired in small amounts of time. Such is the nature of the grandfather paradox.
And have you thought about how many potential hitlers were pruned in the WW2 ... every one that died in the conflict could be much worse than him. So maybe Hitler was a historical fuse. A maniac just 20 years later could have destroyed humanity. Dead serious here, assume that nuclear weapons were available from day1.
So maybe there was time travel manipulation to ensure WWII so that humanity could survive.
Perhaps the WW2 in our timeline is the least worst outcome.... :-|
e.g. What if the Normandy landings had failed? The Nazis would still have been defeated by the Soviets but the whole of Europe north of the Alps could have been occupied by the Soviets, perhaps making a far worse later nuclear conflict much more likely.
This is interesting, but these methods don't strike me as really viable. The Twitter outreach was specifically targeted at the cooperation of Twitter-using time travelers, and while Pope Francis might or might not be historically significant enough to warrant prescient mentioning, I'm sure comet ISON is not. The assumption is also (and maybe it has to be) that time travelers would blurp out important prescient information - however, I don't think that holds true if they were either well disciplined or engaged in historical research - which would mean they know little more (if anything) about our immediate future than we do.
I'm obviously not advocating time travelers are present (I would think with the certain prospect of leaving your time line in order to create another one, the proposition of time travel seems akin to a one-way change in universes that doesn't sound very inviting), but it's definitely fun to speculate about. Realistically, one would also have to take into account the fact that, by mere virtue of being present, a time traveler will change the course of history in the long run.
A more thorough effort could center on large-scale automated data mining for prescient terms on the internet. Of course, there would be many false positives, but as a side effect we could learn more about the epidemiology of ideas even if we don't discover time travelers. It seems to me that a disciplined time traveler would not purposefully drop historically significant hints - however, if they are from a future and culture close enough to our own, they might still reveal themselves inadvertently through idiosyncratic phrases and reference to concepts that are from the future. Hand-picked phrases are not enough to discover this, it would have to be large-scale AI-supported text mining.
If I were a time traveller I probably wouldn't use any of the social networks that are popular for non-time-travellers. Firstly managing so many social network accounts to keep up with the latest fashions would be a right pain (imagine having to change your profile picture on all of them...), but also their 'timeline' view would be completely different to my relative timeline.
I'd assume the network format would be distributed, running on something akin to a phone that you keep on you at all times. Whenever you make a post it records your relative 'life time', or just increments an id, so posts are always ordered in your relative timeframe. When you meet someone it would sync up with their account - I'm not quite sure how that would work though. The issue is you could post something about them publicly that hasn't happened yet in their timeframe (that could be embarrassing). Private messages are even worse...
(N.b. I should probably patent this idea for when time travel is invented)
Nice idea. Although the user-base of time travellers might be a bit limited. I would suggest broadening your product to include the soon-to-be emerging high relativistic speed and FTL travel sectors. Part of the process of friending someone could be to indicate how your respective light-cones intersect, for example.
If your network is ad-supported then there might be extra complications in temporally localising the ad content so that it doesn't induce the wrong kind of causality violations. You might want to give that some thought, now or in the future.
> a time traveler "will" change the course of history in the long run
Going by the current recognized (theoretically possible) understanding of time travel based on Einstein's theory of special relativity[0] it would be only possible to travel in the future (near or distant based on technology that is not yet available).
Travel back would not be possible. And for the entire period of the time jumped the person(s) would not be present.
Based on this theory alone the time travelers would not be able to change history.
Depending on how far they travel I doubt they'd be able to change the future either.
If you are interested in time travel: I saw the movie "About Time" last night and it was both awesome and romantic. Perfect date movie for the geek/non-geek couple.
And now at least this discussion thread is not completely useless :-)
This only covers time travelers from the future. If one were to use similar methods to find time travelers from the past, we'd probably find millions of candidates :)
Travel to the future is actually more probable(theoretically possible), I am basing this on a good explanation by Brian Cox(based on Einstein's theory of special relativity).
The basic premise is that to travel to the future an object would need to reach near the speed of light, the closer you get to the speed the further you can travel into the future, but travelling back would not be possible.
A direct quote from Brian Cox "If you go fast, your clock runs slow relative to people who are still. As you approach the speed of light, your clock runs so slow you could come back 10,000 years in the future".
This is actually something that's more reasonable. Presumably time travellers wouldn't advertise their presence heavily (can you say immediate and massive possible security hazard?) but one way to track them would be to look for net-traffic patterns which matched a person who was trying to localize the day and time, or who searched for things well in advance of them becoming known, general trends, or even being put up on the internet at all.
Perhaps Twitter is run by a cabal of evil time travellers who have created technology to check whether tweets reveal temporal anomalies and delete them automatically to cover their tracks and protect the status of an elite class in the distant future. What if all communications technology has been built around this capability; everything routed through a network of 'security agencies' that ostensibly protect the function of the current government but really work to design a future that benefits a rarified few.
There's a relevant Mitchell and Web scetch. Someone travels back in time and meets Faraday. Faraday asks a bunch of questions, none of which can be answered because the traveller is just an everyday person who has little clue about how things work.
You may have been thinking of this sketch:
http://www.youtube.com/watch?v=oa_hiLXLbTc
Where one guy proposes a modern idea but it makes no sense to people of the past. I think this is one of a 2 or 3 such sketches.
There's a slightly silly-but-entertaining film in which an aircraft carrier goes back in time. The spoiler of the film is that one man who is left behind in time becomes absurdly rich by becoming a pioneering "inventor".
So we should look for absurdly rich people who have made dozens of inventions.
I believe that there was a similar premise in a series of Star Trek: Voyager episodes, where a businessman steals a time traveler's technology and uses it to bootstrap the modern computer industry.
I'm about to go back in time. If I succeed, the silicon transistor gets invented in 1954 and Christmas goes to happen in the winter (northern hemisphere).
If time travel is possible at all, we'd eventually discover and use it. I wonder if this means that we'll destroy our civilization before becoming able to use time travel (seems more likely than time travel being impossible to achieve within thousands of years from now).
One could also posit an Anthropic Principle of time travel: the fact that we still exist means that our universe is among the tiny subset of potential multiverses in which time travel is not discovered, or whose use is sufficiently constrained so as to not result in destruction or paradox.
> If the universe of discourse permits the possibility of time travel and of changing the past, then no time machine will be invented in that universe.
I'm not sure why time travellers from the future would bother to leave prescient messages on the net. What's the motivation? Something like graffiti artists tagging difficult locations?
What I can see them (hypothetically) doing is manipulating present-day financial markets by exploiting their knowledge of future events (e.g. sudden commodity shortages or unexpected mineral discoveries) to increase their wealth. Even small manipulations would produce large downstream gains due to compound interest.
So perhaps market data is a place to look for abnormalities - particularly in existing systems that look for signs of insider trading, or investment accounts/trusts that are untouched over very long periods of time. Of course, such data is usually protected and inaccessible anyway.
Totally serious question: If I go back to 1990, can I distribute a current version of emacs? The toolchain to build the current source tree won't exist for a while.
Why not? Any computer program is just a very large number. Even thought the emacs build process that calculates the large number corresponding to the current version of emacs hadn't been performed in 1990, the number itself "existed" back then as the outcome of any number of other possible computations.
On the other hand, you might have problems with dll dependencies.
GCC stage1 is deliberately written in K&R C so that you can do this kind of bootstrapping. You need a few unix tools (e.g. make - but again, a version from 1990 should work, find yourself a solaris machine or something); I don't remember exactly what emacs depends on, but it should be fine. Getting a modern environment on old unix boxes (or under windows SUA, whose unix stuff is old enough that it comes with X11R5) is fun and usually requires a bit of fiddling but nothing too serious.
I'd say the very fact that most Bitcoins weren't created in the first few hours is a good indicator that there are no time travellers. Or if travellers do exist, access to time travel has been restricted, or perhaps Bitcoins and possibly even currency is not of interest in the future.
In fact, time travel could render investments obsolete.
I think the idea is that they would go back to stop the 9/11 attacks, and then on the day prior would look up "flight 11, flight 175, flight 77, flight 93" in google (maybe in separate searches) to see exactly when/where they took off. They wouldn't mean to leave the clue, but no one should have any reason to connect those 4 flights together until the next day.
There is no such thing as time travel. There is only teleportation. Because you have to have 4(or 10) fixed coordinates to move. Just time travel means you will be in vacuum, rock or middle of a star the moment you arrive.
Since we already found the higgs I think the next line of research should be what exactly gives a particle "the where".
That point is often brought up. But we don't really know how a time-machine could potentially work, so why is teleportation a necessity? If you want to travel to the future you would abuse time delation. While all means to do so pose certain problems none of them involve teleportation. If traveling to the past would work in a similar way the time-machine would move trough every moment until it reaches its destination. If it never has to leave earth or its orbit to do so it would always be affected by gravity and as such end up where you want it to.
I've never understood this logic. If say time travel is invented in year 3000. Then surely by 3050 it would be affordable for a certain segment of society. And be 3070 available for a mass market. And by 3100 available in watch form.
So shouldn't we expect there to be millions/billions of people interfering with the past. A significant percentage of which would be deliberately aiming to manipulate, destroy, communicate, affect and do all the things we expect people wouldn't.
Clearly it means either two things. 1: time travel is not possible. 2: going back in time forks the universe/space-time (About Time is a recent movie that proposes this).
It's been 60 years since nuclear power was invented, so in 10 years it'll be available for mass market? I'd also like my watch form plane.
What if it's so energy intensive that a future dyson sphere can only power it once a year. It doesn't matter how cheap the machine is, if the resources are expensive.
That poses the question whether a civilization that is advanced enough to build a dyson sphere would be able to build a second one somewhere else. The species would have enough time to collect energy and improve the machine until no reachable sun would be usable. And though we don't carry nuclear reactors in our watches (I guess smartphone would be more reasonable these days) we might carry fusion reactors in the year 38000.
Interventions in the past are possible as long as they don't change the future in significant ways. Think of it as Schrödinger's cat who is not dead as long as you don't look inside the box.
Almost, but I'd like to suggest an amendment to your first conclusion:
Time travel may well be possible, but unbounded backwards time travel is clearly not possible.
It may be the case that a machine will be invented that allows people to travel back only as far as when the machine was first switched on.
Similarly, a technique may be invented by which you may be able to temporarily travel infinitely into the future, and be snapped back to your present.
It may be the case that backwards time travel consumes so much of some finite resource that few or no future time travellers could possibly make it into our past.
Garry Kilworth's story "On the Watchtower at Plataea" involves a group of time travelers, from the story's "present", who push back earlier and earlier into the past... until they can't go any further because another group is coming the other way, from the past (due to the technology involved, each prevents the other from going further in their desired direction).
The "present" group then end up, essentially, in a standoff, watching the other group from a vantage point near an ancient Greek battlefield, and pointing out that they must eventually "lose" because both groups are now essentially in normal time. Which is moving from the past to the "present" from which they left.
157 comments
[ 2.8 ms ] story [ 215 ms ] threadhttp://en.wikipedia.org/wiki/John_Titor
> Unfortunately, as of this writing, no prescient tweets or emails were received. Given the additional exposure that the public listing of this manuscript gains, we will continue to search, on occasion, for active tweets and emails involving potential time travel.
http://arxiv.org/pdf/1312.7128v1.pdf
> Although these negative results do not disprove time travel, given the great reach of the Internet, this search is perhaps the most comprehensive to date.
Let's also assume that somebody had a reason to travel into the past, say to kill Hitler. Our timeline would record that an Austrian artist was murdered in the 1920s. We would not consider this historically significant.
I think time travel is inherently very difficult to detect. Even if a time traveller 'dropped' tech. This tech would be recoverable by popping back in time and recovering it.
Everybody kills Hitler on their first trip. http://www.abyssapexzine.com/wikihistory/
http://necrometrics.com/tyrants.htm
And there are monsters like Leopold II of Belgium (possible victims in the range 2-15 million) who hardly anyone remembers:
http://en.wikipedia.org/wiki/Leopold_II_of_Belgium#Exploitat...
Actually, as hardly anyone remembers Leopold II maybe he is the ideal target.... :-|
[NB I eventually remembered that I'm against the death penalty - so what I am actually in favor of is apprehending the relevant individuals and bringing them back to face trial by the appropriate authorities. Although I admit there would be a distinct temptation to do a Cheradenine Zakalwe with Vasili Blokhin:
http://en.wikipedia.org/wiki/Vasili_Blokhin
Where was the Grey Area when we needed it!]
(Good of you to mention Leopold II, though. Also note Henry Morton Stanley's role in that despicable piece of genocide.)
Maybe Hitler was a time traveler himself.
Other wise the people in the future would decide to just let it play.
That's some character...
It takes a certain kind of monster to order the execution of 7000 officer prisoners of war. It takes another kind to carry it out personally with a collection of pistols brought in especially for the job.
http://www.amazon.co.uk/Stalin-The-Court-Red-Tsar/dp/0753817...
http://www.c-spanvideo.org/program/Tsa
edit: Just read the interesting link you posted to 20th centuries bloodiest tyrants. I wonder why Johnson and Nixon are not in the third list, bloody tyrants who killed over 400.000 innocent civilians in the Vietnam war using horrible chemical warfare.
Hell if you are going to do that there are probably countless other things you can do to improve history.
Read the story. This is covered. Quite well, IMHO.
[0] - http://www.viruscomix.com/page382.html
Then you can detect people saying stuff about the future, or possibly attempting to kill hitler while failing miserably.
This would prevent World War 2 and the associated advances in technology, possibly including those leading to the time travel being possible in the first place.
So maybe there was time travel manipulation to ensure WWII so that humanity could survive.
e.g. What if the Normandy landings had failed? The Nazis would still have been defeated by the Soviets but the whole of Europe north of the Alps could have been occupied by the Soviets, perhaps making a far worse later nuclear conflict much more likely.
I'm obviously not advocating time travelers are present (I would think with the certain prospect of leaving your time line in order to create another one, the proposition of time travel seems akin to a one-way change in universes that doesn't sound very inviting), but it's definitely fun to speculate about. Realistically, one would also have to take into account the fact that, by mere virtue of being present, a time traveler will change the course of history in the long run.
A more thorough effort could center on large-scale automated data mining for prescient terms on the internet. Of course, there would be many false positives, but as a side effect we could learn more about the epidemiology of ideas even if we don't discover time travelers. It seems to me that a disciplined time traveler would not purposefully drop historically significant hints - however, if they are from a future and culture close enough to our own, they might still reveal themselves inadvertently through idiosyncratic phrases and reference to concepts that are from the future. Hand-picked phrases are not enough to discover this, it would have to be large-scale AI-supported text mining.
If I were a time traveller I probably wouldn't use any of the social networks that are popular for non-time-travellers. Firstly managing so many social network accounts to keep up with the latest fashions would be a right pain (imagine having to change your profile picture on all of them...), but also their 'timeline' view would be completely different to my relative timeline.
I'd assume the network format would be distributed, running on something akin to a phone that you keep on you at all times. Whenever you make a post it records your relative 'life time', or just increments an id, so posts are always ordered in your relative timeframe. When you meet someone it would sync up with their account - I'm not quite sure how that would work though. The issue is you could post something about them publicly that hasn't happened yet in their timeframe (that could be embarrassing). Private messages are even worse...
(N.b. I should probably patent this idea for when time travel is invented)
If your network is ad-supported then there might be extra complications in temporally localising the ad content so that it doesn't induce the wrong kind of causality violations. You might want to give that some thought, now or in the future.
Disclosure: I'm not a VC in this timeline.
Going by the current recognized (theoretically possible) understanding of time travel based on Einstein's theory of special relativity[0] it would be only possible to travel in the future (near or distant based on technology that is not yet available).
Travel back would not be possible. And for the entire period of the time jumped the person(s) would not be present.
Based on this theory alone the time travelers would not be able to change history.
Depending on how far they travel I doubt they'd be able to change the future either.
[0] https://news.ycombinator.com/item?id=6999933
And now at least this discussion thread is not completely useless :-)
The basic premise is that to travel to the future an object would need to reach near the speed of light, the closer you get to the speed the further you can travel into the future, but travelling back would not be possible.
A direct quote from Brian Cox "If you go fast, your clock runs slow relative to people who are still. As you approach the speed of light, your clock runs so slow you could come back 10,000 years in the future".
That'd be cool.
I did wonder why I couldn't find the clip in YouTube.
So we should look for absurdly rich people who have made dozens of inventions.
http://www.imdb.com/title/tt0080736/
I don't know why HN shows comments from the alternate timelines, I'd file a bug for that if they had a bugtracker.
Or that they have discovered immortality and view us as a subspecies like we would neanderthals.
> If the universe of discourse permits the possibility of time travel and of changing the past, then no time machine will be invented in that universe.
http://en.wikipedia.org/wiki/Niven's_laws
What I can see them (hypothetically) doing is manipulating present-day financial markets by exploiting their knowledge of future events (e.g. sudden commodity shortages or unexpected mineral discoveries) to increase their wealth. Even small manipulations would produce large downstream gains due to compound interest.
So perhaps market data is a place to look for abnormalities - particularly in existing systems that look for signs of insider trading, or investment accounts/trusts that are untouched over very long periods of time. Of course, such data is usually protected and inaccessible anyway.
http://www.frc.ri.cmu.edu/~hpm/project.archive/general.artic...
On the other hand, you might have problems with dll dependencies.
Remember? Eight Megs And Constantly Swapping
My remark about dlls was an attempt at humour, not a comment on practicalities.
In fact, time travel could render investments obsolete.
And if they did prevent 9/11 then nobody would connect the searches anyway, because there'd be nothing to associate them.
Since we already found the higgs I think the next line of research should be what exactly gives a particle "the where".
So shouldn't we expect there to be millions/billions of people interfering with the past. A significant percentage of which would be deliberately aiming to manipulate, destroy, communicate, affect and do all the things we expect people wouldn't.
Clearly it means either two things. 1: time travel is not possible. 2: going back in time forks the universe/space-time (About Time is a recent movie that proposes this).
What if it's so energy intensive that a future dyson sphere can only power it once a year. It doesn't matter how cheap the machine is, if the resources are expensive.
Time travel may well be possible, but unbounded backwards time travel is clearly not possible.
It may be the case that a machine will be invented that allows people to travel back only as far as when the machine was first switched on.
Similarly, a technique may be invented by which you may be able to temporarily travel infinitely into the future, and be snapped back to your present.
It may be the case that backwards time travel consumes so much of some finite resource that few or no future time travellers could possibly make it into our past.
The "present" group then end up, essentially, in a standoff, watching the other group from a vantage point near an ancient Greek battlefield, and pointing out that they must eventually "lose" because both groups are now essentially in normal time. Which is moving from the past to the "present" from which they left.