# If time-travellers always arrive naked how and what would they trade?

In the Terminator movies, time travellers arrive naked and then steal clothes and other items from the locals.

In my society this is also true. However they can carry some things internally in the same way that drug smugglers do.

There is only so much that they can carry. When they arrive, they have to unload the cargo via bowel movements so they can't carry anything sharp or excessively bulky.

Time travel is a closely guarded secret and the exclusive property of a guild. Members of the guild become rich by trading with people in other times.

Questions

1. Given the problems of internal concealment, what can they trade for the most profit?

2. How can they return their earnings to their own time?

3. Should they visit the past or the future? Which is better for trading purposes? How will past and future trading differ?

Note that they must be careful not to change the past too dramatically or they will stop themselves from ever being born.

• If you don't care about legal ramifications and have to strength to impose your will theft can be very effective. youtube.com/watch?v=lYOoWCv_PYE. But in terms of internal carry you also have the stomach as well as surgical alteration to enhance carrying capacity. The T-800 terminator would certainly be able to carry larger as well as sharp objects internally. – Gary Walker Oct 16 '15 at 3:06
• They can carry knowledge of a hidden location which can persist in time and where they can hide items for trade. – Zikato Oct 16 '15 at 13:26
• The question actually says "Ideas Please" ...that strikes me as pretty obviously idea generation. – James Oct 16 '15 at 13:58
• You could always carry a bunch of red diamonds in your mouth. Since they'd mostly carbon, they should be as transportable as say, spit. – Howard Miller Oct 16 '15 at 15:28
• @chaslyfromUK so you're writing a story in which people run around naked with stuff up their butts? I can't imagine this won't be short-listed for the man booker. – dbliss Oct 17 '15 at 15:53

## Knowledge.

• The Market knowing when the market is going to tank or soar.
• Locations of minerals and other resources (Sutter's Mill anyone?).
• Materials imagine bringing fiberglass to the Vikings
• Engineering
• Inventions (maybe Thomas Edison was a time traveler?)
• Trends When styles and trends were likely to take off (hula-hoops to clothing, maybe the inventor of the Frisbee was a time traveler?).
• Music What sort of music will become trendy (maybe the Beatles were time travelers?).
• History being on the "right side" of political events
• Weather (know to plant corn in a year when the corn harvest will be abysmal, know to pull up the stakes of your New Orleans operations before Katrina strikes - Maybe Forest Gump was a time traveler?).
• Insurance (know which people and items you should not be insuring)!
• Knowing the future value of things (there have been times and places when people traded gold for salt, there have been other times and places that sold platinum for less than silver because platinum was a waste product of silver refining).
• Land (which land will become valuable and when it will happen).

Edit 10/16/2015:

• Numbers memorize several sets of winning lottery numbers
• History knowing when to be "out of town" when human disasters will occur like Hiroshima 1945 and NYC 9/11
• This also avoids the problem of having to carry things inside of you. – 2012rcampion Oct 16 '15 at 4:44
• Also, what day to not be in Hiroshima. – Erik Oct 16 '15 at 7:22
• you may also want to add lottery numbers to that list - acquiring the price of a lottery ticket would be quite easy. – MD-Tech Oct 16 '15 at 12:11
• @Kii, If you know that Volkswagen stock is about to tank because they cheated on diesel emissions, it's possible to set up a trading strategy to make a ton of money without affecting anyone else. A few large trades might affect stock prices a little, but it's a pretty "safe" way to make money because the effect on others is so small. – JPhi1618 Oct 16 '15 at 14:55
• but in the future you always won the lottery. Did the Doctor write it or did Beethoven? – MD-Tech Oct 16 '15 at 14:57

My very first thought was drugs. Not just because of the method of transportation, but also because if you live in a time period where say, opium is used as a cure-all, you could totally take it forward to a time where it's illegal and sell it at a premium.

Maybe even historical artifacts that are in better condition than the versions they'd have in the future. (Check it out, world's first mass-produced sim card as it looked the day after it came out!)

• This would have been my answer. Grab cheap-past items, like gold and drugs, and poof to a future where these things are rare. – vulpineblazeyt Oct 16 '15 at 17:19
• @vulpineblazeyt: When and where in the past was gold ever cheap? – Mason Wheeler Oct 16 '15 at 18:00
• @MasonWheeler, at every point in history it's cheaper than it is today. But since we can pick-and-choose, I'd say California Gold Rush. – vulpineblazeyt Oct 16 '15 at 18:52
• @vulpineblazeyt: Yeah, that's why everyone was rushing to acquire it: because it's so cheap! :P – Mason Wheeler Oct 16 '15 at 18:53

# Labor savings

In mining, surveys must be conducted to discover the locations of ore deposits and such. Write your time travel laws such that the following can occur:

1. Time traveler Alice appears in the year 1800 on August 5, promises Bob the miner that she'll bring back his survey results for \$1000. 2. Bob agrees, and spends \$50,000 on a survey to find the best place to mine coal. The survey is completed in 1810.
3. Alice memorizes the survey results. Alice travels back to 1800 on August 6, and sells Bob the results.

Bob has saved \$49k and Alice has profited$1k.

This technique for bringing memorizable information back in time could have a number of applications, including:

• Mad Scientist support - want the results of a 5 year experiment in 5 minutes?
• Accident prevention - want to know the week before a lethal accident blows up your fireworks factory? These time travelers could one day even become required by the insurance company.
• Wartime strategy - better hope both sides don't have one!

Due to the risk of paradoxes, this industry may grow to become highly regulated. Presumably the Guild will handle this regulation, and dispose of rogues before they go rogue.

• Such trade changed the history. All people who earned those \$50K needed to find different jobs, possibly travel, married other people... pooof! Bush loses 2000 election, Al Gore win, humanity solves climate challenge, time travel is invented 2080. – Peter M. - stands for Monica Oct 16 '15 at 15:30

Well, instead of bio-bags (which I like), how about small containers like Tupperware or ziplock backs under the skin? The 'zipper' could be concealed, but easily opened. Would at least be easier than the drug smuggling approach. Really, if time travel is possible, extras dimensional containers aren't that implausible. (Like bags of holding in Dungeons and Dragons).

Also, things need not be material, to be valuable. How much would someone pay for a vial of fresh, refrigerated, dinosaur blood? Or a Dodo bird egg? Or DNA of the 'missing link'?

If amnesiacs can be created (fool proof drugs to erase short term memory) then rich people could pay a million dollars for five minutes with Jesus of Nazareth. Or Napoleon. Or King Arthur.

Just try to get them when they aren't going to be busy (scout ahead, then go back and get them during their down time.)

Might be a minor plot, when someone kidnaps a visitor from the past, and have to find them in 5 hours- that's the limit of the amnesiac.

• I wonder what a fervent christian would actually say to Jesus. Probably they would just want to touch his robe. The problem would come from the constant tourist trade to meet Jesus. He would end up having no time to do any miracles because he would be forever signing autographs. The tourists would get back to their own time and find that Christianity had never happened. Maybe John the Baptist or one of the disciples would have had to step in and be the messiah. – chasly - reinstate Monica Oct 26 '15 at 0:21
• @Redchigh I tried to imagine smuggling dodo egg in a body cavity... that would hurt :D – Shadow1024 Nov 30 '16 at 21:24

The problem with becoming rich from this is the butterfly effect. This effect would easily prevent you from going back in time let's say to 1980 and buy stocks in Apple. On a smaller scale buying chicken from a local grocery store may eventually lead to the bankruptcy of Apple because the guy from the grocery store founded a rival company.

• Yes, the butterfly effect is their biggest problem. How about if they travel to the future though? That way they won't affect their own past. – chasly - reinstate Monica Oct 16 '15 at 0:47
• But then they have no idea what will be valuable – jwiz21 Oct 16 '15 at 0:51
• Well they can go back and forth and find out. The question I am asking is what would be valuable to the future? Presumably their technology is better than ours so what can we offer? – chasly - reinstate Monica Oct 16 '15 at 0:54
• We could potentially offer live specimens of then-extinct animals. In the far future, we could offer pre-post-human specimens who haven't evolved down a particularly bad path just yet, giving their engineers a better way to fix the post-human DNA. Then there's always "ancient" artifacts that happen to be in pristine condition. And if you can bring back even child's toy from the future, the tech could make you a billionaire. Something as silly as a butter knife could be traded to an antique collector for something useless to him and Earth-shattering to us. – MichaelS Oct 16 '15 at 10:07
• How is being one of thousands of investors in a huge tech stock like Apple, Google, Netflix, etc going to affect anyone else? Sure, don't set yourself up as a majority seed investor in a startup, but investing relatively early seems to be the safest thing you can do. – JPhi1618 Oct 16 '15 at 14:59

How to carry very valuable items back in time within your bod? Interesting question.

Forget diamonds and gold. Give me an iPhone and send me back to the 1980's.

Transferring either small technology or information back to the past would be far more valuable than any single item made of a precious substance. Think of how much we would pay today for the cure to cancer or cold fusion.

I'm pretty confident I could swallow a micro SD easily, and if you know anything about micro SD cards it's pretty easy to mock up a card reader. That's a lot of information you can transport, here's a few ideas;

1. Medical breakthroughs
2. Technology specs
3. Government political (de)classified information
4. Knowledge of future events - earthquake mitigation etc.

So go to the past. Once you have the money, buy something that will never get devalued. Land is probably a good shout; or a material that becomes more highly valued in your present (rare earth metals might be a nice on).

• They wouldn't be able to talk to anyone on an iphone or download anything. There would be no network. – chasly - reinstate Monica Oct 16 '15 at 0:45
• You misunderstand me. I'm saying the iPhone itself is the valuable. Take an iPhone to the 80's and reverse engineer it. – FraserOfSmeg Oct 16 '15 at 0:47
• Mock up a card reader with period materials? Protocols, high-precision high speed serial links... you would only have materials to build one for a few years prior to its real introduction. – JDługosz Oct 16 '15 at 11:54
• I'd argue that a scientific/industrial community that isn't capable of producing chips on the micro-level of an iPhone wouldn't be able to reverse engineer very much of it either. They might be able to glean some knowledge, but its not the one item I would shove inside of me. And that form factor... Not pleasant. – JPhi1618 Oct 16 '15 at 15:03
• Things like the iPhone use cutting edge manufacturing techniques, having the design for an iPhone wouldn't be useful without also having the design for all of the manufacturing equipment, a lot of which uses cutting edge technology in its manufacture so you couldn't even just build those with plans either. Sure you might be able to speed up progress a little, but iterative design improvements would be mostly useless, it's things like the idea of a vacuum tube, or a solid state relay that could have been made with old manufacturing techniques that would be incredibly valuable. – Rick Oct 16 '15 at 16:06

## How to make money

Data.

With access to the knowledge of the future, governments and large companies would happily buy research that is yet to be done. Do you have an issue with the bootstrap paradox? Imagine going to Google today and giving them all of the information about their mistakes and dead-ends in the future, what makes them successful etc.

You know what a learning experience is? A learning experience is one of those things that says, "You know that thing you just did? Don't do that -- Douglas Adams.

Imagine a learning experience without having done "that thing you just did".

Imagine going back to the 1920-1930s and giving some nation of your choice all of the future science and research on atomic weapons. Imagine how many people would pay to publish the general theory of relativity before Einstein even published the special theory.

Transfer all of this information on a memory card inside a small smartphone and write it up by hand. Alternatively, the traveller can post on here asking for advice on how they could print files with technology from previous decades and devices that can fit into one's anus - it wouldn't be the strangest question to be answered here!

## How to keep the money with you

The problem then is what happens to the money you earn, and how you would take it back. My answer is that you don't. Use modern day knowledge to build a condition-preserving bunker, in the past, in a permanently-remote location. Use your money from trades to buy famous pieces of art, original pressings of books/records, a model-T Ford hand signed by the man himself, with zero miles on the clock. Get back to the future, open the bunker and report the find (Donate 60% to a small town museum) to remove suspicion. The rest will make you billions.

You will be revered amongst 'normies' as an adventurer, an Indiana Jones-like character. You can pay off some companions to make some other "discoveries" to remove all media attention from yourself. You can plant stories in the past to hint of such bunkers, with sufficient mystery surrounding them to make them unfindable.

This storyline sounds like a hell of a lot of fun.

• Such a vault would be hard to keep safe. Other time travellers could loot it while you are not looking. – JDługosz Oct 16 '15 at 11:56
• Proliferation of knowledge about nuclear weapons might put some dent into history ... – Hagen von Eitzen Oct 16 '15 at 17:22
• It certainly would. However, in the event the world is wiped of all profitable forms of life, you could just jump back and stop yourself. This assumes that your existence is not determined by actions on earth - if you were from an alternate universe or another planet (specifically with no relationship between events on earth and your birth), there should be no issue, so long as your loot is safe and you only iterate forwards in your adventures. I gathered by the question that such a character isn't the most ethical of beings and is in for profit - it makes me wonder what the point is though. – Jake Oct 16 '15 at 17:29
• Memorize a list of valuable coins and stamps, including date of circulation. Buy them as soon as they come out, then hire a bank vault you know has been around since then and pay in advance for 100years or however long you travelled – nzaman Jul 20 '16 at 9:01

Work in the crematorium of a prison that executes prisoners. When a body is about to be disposed of, because no family will claim it, use the skin-bag to store your gold or platinum in for transport. (Dispose of the meat and bones in the usual way so as not to arouse suspicion.) When you transport yourself, make sure to set it so you get there 30 seconds or so before the skin, to make sure you are alone and no one sees you. If someone does, make sure they approach you and have them standing in the EXACT spot the cargo materializes, vaporizing the witness in the process.

While there are already very good answers, especially about trading information, I would also mention one more possibility that is not yet covered.

Since this kind of time-travel requires for the transported object to possess a living exterior, it should be possible, with that level of science anyway, to create bio-bags. It could be an artificial non-sentient lifeform with a big cavity inside that could be filled with objects.

There are big possibilities opening with that approach, depending on what you want to have in your plot - for example, the lifeform could be in need of nutrition, and keeping it alive and fed up during the journey may give an additional point of concern for the characters. Or it could go rogue. Or a big enough bio-bag can be used to send a spaceship in time...

However, if you postulate the need of a living exterior for the time travel, I would reasonably ask "why so?". Back in the days when the Terminator movies were made, it was enough just to postulate this. Today's minds are already more hungry for knowledge and reasonability. I still question myself, what could be the technical reason for the limitation in Terminator.. and why did not they use bio-bags to send more stuff when the terminator itself is essentially a bio-bag for the robot?

• Answer: Because only a living organic mind can control the time travel due to the physics involved playing havoc with computers. – Joshua Oct 16 '15 at 15:22
• @Joshua Yes, a good concept that I like, linking dreaming to travel. It has been used, for example in Andromeda where only organic brain could manage the hyperspace, or Dune, where the Navigators were all former humans.. however, 1) this does not stop one from taking a tonn of things with him since the travel is physical (not only astral body travel) and is supported by immense energy of a machine, so one does not have to rely on capacity of how much he can carry, and 2) terminators T-800 and T-1000 do not have an organic brain. – noncom Oct 16 '15 at 15:29

I think the most important information to trade would be intelligence on enemy time-travellers.

Your model of time travel is quite important. How are paradoxes resolved? Is this overwrite style, whatever can be changed already has been (like time crimes),or coexisting multiple timelines whenever a new branch is created?

• No-one really understands how it works. They inherited the time machines and have lost the knowledge required to make more or even to reverse engineer them. They don't dare to ask for help from other people or other times because they don't want to reveal their secret and lose control of the source of their power. The suspicion is that there are multiple timelines. However it really works by natural selection. People only return to their own time if they haven't made a mistake. People who don't return cannot be asked what they did wrong. – chasly - reinstate Monica Oct 16 '15 at 17:05

Strange answer but bare with me... forget the idea that what you change in the past will change the future as misunderstanding both the past and the future. What you do in the past has already happened in the future that you came from. I will try very hard here not to spoil the latest episode of Doctor Who... I will spoil a Star Trek movie, however, on the basis that its a throwaway line. Think, if you will, that when you go into the past you enter a timeline that is fixed in your time. By giving the secret to transparent aluminium to someone so that you can build your whale tank you are actually giving the inventor of that material the idea that they had in the past. To quote Scotty: "Why? How do we know he didn't invent the thing?" By going into the past and "changing" something all you have done is complete the circle. Scotty does not change history at all by giving the formula to someone in the past, he simply makes the past happen.

Now expand this to your time travelers' guild, or "time lords" as we might call them (knowing wink). That the guild is rich, is powerful, or even has the time travelling ability in the first place is due to them "changing" time or rather being a part of the past. Nothing that they do has any effect above bringing the past in line with the future.

• The "transparent aluminum" bit is actually very interesting. Corundum (aluminum oxide) is a transparent material of amazing hardness, close to that of diamond, with incredible potential applications as both an industrial and a structural material, if only we had a good way to produce it in industrial quantities. But since it's difficult to come up with in large quantities, it mainly remains known by its more common name, sapphire, (or alternatively ruby, when the corundum contains red impurities rather than blue/green ones,) and used for less practical purposes. – Mason Wheeler Oct 16 '15 at 18:10
• If someone in modern times did invent a way to mass-produce high-purity corundum on the scale Scotty wanted to have available, he would indeed end up wealthy beyond the dreams of avarice. – Mason Wheeler Oct 16 '15 at 18:11
• My point was meant to be more about solving problems in causality than strictly about any one substance! If I'd swapped Corundum for Beethoven's symphonies would you be saying the same? – MD-Tech Oct 16 '15 at 18:21

If Bitcoin is still around, they could simply create a brainwallet and memorize it. They could then find a cheap smartphone, install a bitcoin app, and start spending their bitcoin, assuming the bitcoins have already been mined by the date at which they arrive.

• This is more a comment than an answer – bowlturner Oct 16 '15 at 15:55
• You wouldn't even need a smartphone. A Raspberry Pi connected to coffee-shop wifi would be good enough. – wizzwizz4 Nov 17 '18 at 14:23

The human body is capable of becoming quite large. People have grown so fat as to become immovable, except by crane. Such a large person could have parts of their body fat replaced with storage containers. They could work in a team with a skinnier, more mobile time traveller, bringing large artifacts with them. Presumably there would be future tech that would allow such body modifications to be simple and reversible.

When the PS2 came out in Japan about 6 weeks ahead of the USA, people would pay 2,000 dollars for a Japanese PS2 that only cost 700-800 dollars there. It WOULD be possible to surgically implant these in the intestinal cavity. I'm not saying it wouldn't hurt. When the PS3 came out, people sold their PS2s for as little as 5 dollars 2,000 dollars from 5 dollars is pretty good. (What is the fuel cost of a time jump?)

Around 1995-1996 the earthquakes and flooding that destroyed the manufacture of SIMMs for computer memory in Malaysia. The price went up from a thousand-fold for memory already on the shelves. It took years to recover partially. Then another series of floods wiped out production again. Sticks of RAM in body cavities would be easier than surgery for a complete game system.

Sierra Leonne, the diamond fields. Can you timejump from outdoors in the open? or do you need a large device? I do not require a device, I prefer to grab the merchandise and jump from a high place before transporting myself, people assume I am dead and don't look for me.

I have been thinking about the diamond fields for a while now but have not tried it yet. If anyone speaks the language there and can assist me, I can comfortably carry 3-4 small-average sized individuals along on each jump with me. leave a msg here, I will check back next time I am in this century. Yours truly, -D.B. Cooper.