A talented whitehat hacker from the near future (around 2050), through events outside their control, ends up somewhere between 100 and 1000 years in the future. They have no idea what time they ended up in, except that it's in the future because the area they landed in is a military base full of exotic materials and inventions. The event that caused their transposition in time was a failed military experiment. Obviously they're arrested, but only after they almost managed to escape the base. They carry with them a smartphone, a smartwatch and smart eyewear, all with a personal AI (imagine Jarvis from the Iron Man films) they grew himself. Because of the experiment, these smart devices have basically been molded into their body, so they're basically a cyborg.

How can this person figure out what time they landed in, and how much more advanced the technology is?

The main things I'm wondering about:

  • What signals or input can their smart devices and AI notice to get an idea?
  • What can they personally tell from their surroundings and their capture?
  • During their debriefing after their capture, what questions can they ask? Assume that the military does not consider them harmful and is willing to answer his questions to make him feel at ease.
  • 1
    $\begingroup$ date +%s + Moore's Law. $\endgroup$
    – wizzwizz4
    Commented Sep 2, 2016 at 8:56

7 Answers 7


How can this person figure out what time they landed in, and how much more advanced the technology is?

  • During their debriefing after their capture, what questions can they ask? Assume that the military does not consider them harmful and is willing to answer his questions to make him feel at ease.

Well, he certainly could ask simply "what year is this?". Alternatively, in case he has reason to believe that the calendar has changed too much in the interim, some variant thereof such as how many years have passed since some major event that happened during or before his lifetime the date of which he knows, and they are likely to be able to find out without too much work. That would quickly give him a fairly exact idea of what time he has ended up in.

He was time-transported as a result of the military's own experiment, which leads me to believe that he showed up in close proximity to the experiment apparatus while the military was operating that apparatus, so it seems reasonable that the military would make some sort of connection to their experiment. Even if the military's experiment didn't directly involve time travel, it stands to reason that under the circumstances, he might get some benefit of the doubt (if he didn't blow that by his attempting to escape).

He could probably produce some sort of identification documents as well. It would be difficult to show that he is who he claims to be if he appeared a millenium from now, but a hundred years into the future it wouldn't be completely unreasonable for a military officer to be able to interpret, say, a driver's license or something similar.

Assuming that he doesn't need to conceal the fact that he is from their past, the situation you describe sounds quite easy to solve without needing to resort to explanations centered around any advanced technology.

After that, it depends very much on whether the military is willing to set him loose (in which case he'd probably fairly quickly get an idea of the technological level of the society he has ended up in, simply through observation), or if after the interaction with the military the hacker is considered enough of a threat to warrant some type of incarceration (in which case all bets are off except for basically the questions that get answered by military and possibly law-enforcement officers).


If all else fails, look at the stars.

It's reasonably easy to calculate the evolution of stellar positions over time.


It is therefore also possible to backsolve by looking at a number of stars and their relative position to calculate what year it is.

Note that this requires very accurate measurements to give short time scales. However with all your fancy smart devices it should be possible. As long as he can get a good view of the night sky, anyway. He might also be able to figure out where he is, if that is in doubt.

For more info about his situation, it is very unlikely he can interface with the local tech. However, low tech solutions might still work. Somewhere in the world, someone might still be using short wave radio, for example, and that can tell you a lot. Personally I am very skeptical he'd get anything from the military. Those guys don't like to share.



Assuming she (or he) can find a child without looking suspicious, children love the attention of a game. Ask their age, note how smart they are, and ask if they're really, really smart can they recite the day, month, and year all together?

We've had our calendar around for about five hundred years, although it wasn't widely accepted until the 1700s. This lends me to believe that some strong semblance of it should remain for a while. This also keeps suspicious adults from reporting you to authorities in the unlikely event that they think you're dangerous/crazy.

Your Internal Technology

Your character is now pretty savvy with very powerful internal technology. Presumably a connection to whatever wireless technology is available. Luckily for you, as well, by then electronics will hopefully be chargeable remotely, so you won't need to plug yourself in.

The Trash

Humans love to date and time-stamp everything we can. I don't know of a newspaper that doesn't have a date on it, or BBC.co.uk articles, as example. Files, letters, electronics, data, the hologram-news in downtown, whatever it is, a date will come up, and your fancy internal computer can figure out how to process it no matter how cryptic it might appear: things are dumbed-down and made intuitive for people, so it should be easy for your protagonist.

Bonus: Have no fear. Nobody knows what the technology will be like in 1000 years (or whenever you landed), of course, but if I found an abacus from a thousand years ago, I could figure out a way to work it. Someone friendly in this brave new world should be able to upgrade you.


What signals or input can their smart devices and AI notice to get an idea?

rdate still works today.

Sure NTP has supplanted it for most applications, but the trivial "ask server for current date" protocol is common enough, and at least 50 years old.

I believe it will be similar in the future: his equipment will be still able to connect to local cellular networks using the oldest legacy protocols, and pull time&date from the network.

What can they personally tell from their surroundings and their capture?

"Secret military base, probably alien stuff". More probable than time travel. You know the army experimental tech is by decades ahead of us. It's really not representative of the times.

OTOH, approximate date (+- 3 years) would be easy to spot from writing on many, many common-day objects.

  • fire extinguisher expiry dates
  • pretty much any computer; date and time being "somewhere on the desktop" is a standard that's unlikely to be gone.
  • papers, orders etc. As long as paper is still around.
  • Food expiry dates
  • manufacture dates on manufacturer's tags on anything.
  • release dates of books

During their debriefing after their capture, what questions can they ask? Assume that the military does not consider them harmful and is willing to answer his questions to make him feel at ease.

We know a bit too little about our hacker to know what would be interesting to them. I can foresee two basic avenues of investigation:

  • curiosity-based: "How did you do it?" "Would you consider hiring me?" "What happened over the time?" - gleefully embracing the future
  • fear-based: "Can you get me back home?" "I'm not a copy, with my old self still in the back?" "What will happen to me now?" - with crippling fear that the soldiers will get rid of all traces of their mistake in the easy way...
  • $\begingroup$ A, say, NMT cellphone would likely be pretty much useless even today, and NMT was introduced only ~35 years ago. Since then we have gone through NMT, GSM, 3G, are deploying 4G and talking about 5G. Even just 100 years is likely to see the obsolescense and replacement of cellular communications protocols many times over. Even if the software in a smartphone could theoretically adapt to the protocol changes and the network would talk to it in the first place, there are limits to how wide a frequency range can be covered by a transmitter. $\endgroup$
    – user
    Commented Apr 26, 2015 at 20:30
  • $\begingroup$ @MichaelKjörling: But GSM still works and SMS messages, despite all the expansions still carry time&date as in the first days of GSM. NMT was pretty much an experimental technology with little room for expansion. Since GSM many new standards were introduced but all build on top of legacy ones; if you want to use WAP over GPRS, you still can. Have a different example: TCP/IP networks or Ethernet. Essentially, without a huge technological leap like analog->digital, you can expect legacy standards to linger for a long, long time. $\endgroup$
    – SF.
    Commented Apr 26, 2015 at 21:50
  • $\begingroup$ You make a valid point about digital vs analog and similar leaps, but again, 100-1000 years? TCP/IP vs Ethernet is a different kettle of fish, considering that they operate on very different levels (Ethernet specifying the physical and electrical interface, TCP/IP being merely one way to transport useful payload data over any number of types of links). IP vs IPX, or coaxial vs twisted-pair Ethernet, or Ethernet vs Token Ring, might be a more reasonable comparisons. $\endgroup$
    – user
    Commented Apr 27, 2015 at 9:55
  • $\begingroup$ @MichaelKjörling: 100-1000, yes; no way. But 50 is still doable. Coaxial ethernet is out of use but if you manage to get your hands on a dual-media hub, you can connect your PC with coaxial Ethernet to a 10-gigabit network just fine. I believe GSM is still the best example; new technologies are being built on top of the stack but the legacy ones linger and don't seem to be going away anytime soon - phasing out the standard voice GSM system to be replaced with VoIP or leaving only MMS while doing away with SMS doesn't seem to be on any agenda anywhere. They are to stay, period. $\endgroup$
    – SF.
    Commented Apr 27, 2015 at 11:02
  • $\begingroup$ OP specifically wrote: "A talented whitehat hacker from the near future (around 2050), through events outside their control, ends up somewhere between 100 and 1000 years in the future." followed by "How can this person figure out what time they landed in" $\endgroup$
    – user
    Commented Apr 27, 2015 at 11:05

Moore's Law

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Assuming it stays true to history one can calculate with variable accuracy what level of computation will be present at any given year. Reversing the function to instead produce a year would be an easy to determine the time, given that the built in smart devices have basic x-ray scanners. Unfortunately there is the possible discrepancy if/when quantum computing becomes feasible large scale as it carries the great possibility of completely changing the design of modern computers.

Additionally, if their smart devices carry advanced logic and reasoning, they may have the ability to simply cross-reference hundreds of technology prediction statistics and create an educated guess about the year.

  • 3
    $\begingroup$ Assuming Moore's Law will hold for another 1000 years is a very bold assumption, IMO. We are already starting to hit actual physical limits that impact our ability to evolve semiconductor technology in the same way we have previously; that's a big reason for the switch to multi-core CPUs, for example. You may also want to compare something like this answer to What's all the carrying PADDs around?, and particularly the third paragraph of that answer. $\endgroup$
    – user
    Commented Apr 26, 2015 at 18:47

Good news
By going to any computer connected to the internet and asking a world time server, "What time is it?"

  • Or access to any GPS device would also give you the time / date.

It would be difficult to not discover the date if you had access to a computer of that era.

Bad news
However, 100 years is a loonnnggg time for technology. It's likely the communications protocols for wireless and wired connections would no longer work. In fact, the frequency allocated for the devices could have changed (e.g. the protagonists wireless phone might emit signals in a frequency now restricted for military use).

But even sending and receiving signals in the proper radio frequency doesn't mean the future devices will speak to the protagonist's devices. Heck, data storage technologies, data storage formats, operating systems, file systems, file formats, computer languages, etc. will all likely have undergone 1 or more drastic / dramatic changes. The underlying technologies, the strategies for doing these things, and the programming to control them will all have changed too much for 100 year old implants to do much with the future tech.

Imagine interfacing a Cray computer with a WWI era navigation plotting table on a ship, it just wouldn't work and it is unlikely that any amount of reprogramming would enable the devices to adopt the new standard.

How would a current era computer speak to one that no longer recognizes TCP/IP for network connections? How would you reprogram an Ethernet controller to speak to a wired connection that doesn't use Ethernet network standards?

Furthermore, I remember using computers 40 years ago. At that time I could type faster than the computer's network connection could transmit data. Current data transmission speed might be something like 40,000,000x faster than the communications of that era. It is likely the protagonists "implants" won't even know they're being talked to and if they detect the signal no amount of programming would enable it to make sense of what its receiving.

Imagine a multispectral network connection using many colors and polarizations of light to transmit data. Unless you had a future receiver capable of detecting and decoding such a message your hardware might only be able to tell there is a signal. Since it will miss most of the message (that transmitted in other frequencies and polarizations), there is zero chance of making it work.


The simple device should be sufficient.


From wikipedia

Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon (14 C), a radioactive isotope of carbon.

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    $\begingroup$ C14 dating does not tell you the exact age of an artifact, but only gives ranges of ages (the object can be 600 years before present or 640 years before present). If you don't know when your present is, you are pretty much stuck. $\endgroup$
    – L.Dutch
    Commented Mar 20, 2017 at 13:01

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