# What would be valuable in a world with time travel? [closed]

In a world that exists in the close future (think 24th century) TARDIS-style time travel is fairly common; most governments and businesses have access to it. The ability to jump anywhere, anywhen means that the value of most materials- gold, silver, osmium, etc.- has gone down significantly.

If I'm a time traveler looking to use my machine to make money, what material or substance could I bring from the past or future that would hold its value?

Note: the longer back or forward the time jump, the more difficult it is.

• This feels pretty broad. How many people would be making money this way, everyone? What is the purpose of money in this future society? Is the money not backed by something? What is that money backed with? – Trevor Jan 21 at 18:38
• How does travel handle paradoxes? If you go back in time and steal all the gold that backed, say, the dollar, then would that have any impact on the future economy? What would happen if you get a material that was actually used at some point (used at t0, you get it from t(-1)) – VLAZ Jan 21 at 19:10
• Going back in time and "acquiring" just about anything is probably going to be theft. That said, you'd probably steal art or other valuable artifacts. People in your time would probably desire stuff like the scrolls of Alexandria. (Recommended reading: The Gordian Protocol.) – Matthew Jan 21 at 19:35
• Alternatively, though this sort of inverts your question, you would go back in time and buy stock (or otherwise invest) in a company that is doing well in your time. – Matthew Jan 21 at 19:36
• If I invest LOTS of money to jump to 1400 AD and set up mining corporations that siphon the gold out of everywhere that's about to be colonized - does that gold then disappear in the future? Assuming a finite supply, couldn't the person who goes 5 seconds farthest back steal everyone else's gold before them? – Zxyrra Jan 21 at 20:04

Safety is the only valuable commodity in the world that you've described. With unregulated time travel occurring constantly, paradoxes would become a threat to everyone. Getting erased from existence becomes a very real possibility.

Fortunately, the threat is relatively short lived. Giving humans a tool of such immense destructive capability will inevitably lead to someone going back and killing the time machine's creator in his crib. They might be wanting to save the world or just get their time-lost love back from oblivion, but someone somewhen will find a good enough reason to want to reset the whole idea of time travel and put the genie back in the bottle.

Which leads back to the safety opportunity. Find some wealthy people and offer them a trip back as far as the time travel technology can take them; to a moment so far in the past that forward-flowing paradoxes cannot reach them. Let their fortunes fund the establishment of a high-tech camp in the distant past and then live there in safe luxury until the inventor's death snaps everything back to normal.

Depending on the specifics of how your universe actually handles time travel, this venture might turn out to be a scam. The paradoxes might still reach your younger selves who are still in the future and that might spawn a new paradox which erases you from the distant past. But if you sell it well, the rich people who fund the whole project might not realize the error until it is too late.

You did say that you wanted to make money. You didn't say anything about continuing to exist long enough to keep it.

It depends on how long your civilization has had time travel, and whether or not there are restrictions on traveling to time periods prior to the advent of the time machine. There are a few things to consider here for dealing with typical materials.

Ruining the Future

Let's say that time machines themselves are an in-demand commodity, and a major raw material which is needful to create time machines is (just an example) erbium. Erbium is rare, but necessary for everyone's expected quality of life (because it's a component in time machines), so it maintains a state of high-demand.

Erbium is hard to come across, but was relatively inexpensive at the time people were just beginning to gather and refine it into time-machine grade metals. If someone were to go back to the time just before time-machines were popularized, they could gather a large quantity of the material for little cost, but they would risk disrupting the advent of time machines themselves (and without time machines, erbium isn't so valuable anymore). Thus, while harvesting Erbium from other time periods may be legal, it is only profitable to take Erbium from times after a certain date.

Leapfrog Mining

Now, each time period will desire a certain supply of the material in order to manufacture their goods. Knowing that, different periods in time may desire to prevent the future from harvesting their Erbium. If one goes to the past and takes Erbium from the ground in the year 3042, they prevent a business which otherwise would have acquired the same Erbium in 3058, and so that other business will instead send its time travelers to 3035. In response, you send your miners even farther into the past, until you reach the legal limit. So, all past-harvesting operations must default to the earliest time period allowable.

In addition, in order to prevent actions which would cause society to fail to develop properly, harvesting operations in the past must only take materials which would have otherwise remained untapped or undiscovered until the origin date for the operation. For example, suppose I live in the year 5600 and I discover an untapped Erbium mine in my back yard. It's unbelievable nobody noticed this before. I want to mine it, and I want to secure my investment from time-leap-frogging. So, I invest in some gear and send it to the profit-time-wall and begin harvesting then. This means that the quantity of a material available at any time is still limited to what you can find that wasn't already tapped. So, mining from the past doesn't reduce the value of a material.

Future Harvesting

In a real way, the market could easily be flooded by taking tons and tons of erbium from the future, maintaining stable time loops in order to cause a massive amount of future erbium to exist in the present. Of course, this is necessarily a temporary scenario; the time loops eventually end, and the material returns to its origin time, and in the end the quantity of erbium in the market goes back to what it was before. So, flooding the market with future-materials does not permanently decrease the value of the metal.

Time-sensitive materials

Maybe most relevant to your question, there are lots of materials which could only reasonably be made useful in a world with time machines. For example: Astatine (or any of those man-made elements which only exist for a few ms at a time). It's got a really short half-life, so making anything useful with it before it disappears is very difficult. However, if you could trap it by constantly sending it to its prior time-state, you could find uses for it. Metals like this would be necessarily rare because of the technology required to stabilize them, and their uses could be any kind of scifi stuff you want. Maybe when we finally have a George-Washington-Carver-of-Astatine appear IRL and find some great uses for it, we'll discover that it makes great laser guns and lightsabers. Who knows!

How Time Machines Change the Raw Materials Economy

The stock market depends on uncertainty about the future. We buy stocks in Company X because we think they're going to succeed, and we want to see the value of our stocks increase. Company X uses your investment to increase their odds of success, and everybody wins. But then, Company Y invents a new disruptive technology and Company X goes out of business. If we could have predicted that, we wouldn't have ever invested in Company X. So, publicly traded companies, investments, and venture capitalism can't exist alongside time machines. In fact, competitive economics break down almost entirely -- we know who will finally make the best item of X category, and so we really have no choice but to give that company a free monopoly over that item... but monopolies are harmful. Thus, after time machines are invented, we can't be capitalists anymore. The only possible economy is one where the price of every item is regulated -- maybe communism or socialism. But if you want to avoid the corruption that historically comes with a few individuals controlling all the means of production, I'm thinking some kind of technocracy where the algorithm performs the role that a far-left government would otherwise perform, regulating prices and basically owning every business.

So, let's say the price of your raw material is determined by the technocratic algorithm. The algorithm measures and decides the needs of each sector of the public, and redistributes raw materials according to whatever goal the algorithm was designed to have. Is it to make the most people comfortable, or to make everyone equal? Does it prioritize defense, devoting most of its materials to military research, or does it prioritize art, distributing its materials to public infrastructure? Either way, the value or a raw material is determined by its priority in the algorithm, and the algorithm might not trade money for it; it might just take the material as its due.

I can think of a few ways to make money.

(1) Match making. Find your soul mate across the the span of time. Even the mostly lonely heart will find someone in all of human history. You just might be your own grand father.

(2) Talent shows. The timeline has talent. Like bring Beethoven forward in time compete music competitions or bake-offs. Erase his memory then take him home.

(3) Domestication of Exotics pets. Travel in time and cull isolated T-Rex and velociraptor populations to produce breeds that adore human beings and not human flesh. Sell them for big bucks in future.

The ability to travel time does not take away the need for materials. On the contrary, having the resources NOW and available would be expensive, since knowledge of, for example, known metal deposits is easy to get, and can be harvested in several moments in the past. Whoever agency can get hold of the deposit farther back in the timeline gets the prize, leaving others empty handed. Energy generation to power the time travel would also be expensive to install and mantain. As professions go, Private Investigators would be appreciated, since they would be able to blend in different eras and places to get information about lost and unknown treasures. Spying would also be a hot issue, industrial, governmental and the such.