I found a time travel machine. It can travel back in time very precisely.

I don't have any specific skills, except for my very good knowledge with programming languages and programming patterns.

I want to travel back in time to become rich, to do so, I want to bring with me the knowledge needed to invent something before it gets invented by the real inventor.

For example, I could go back in time before the invention of the paper clip and convince someone to invest in "my" idea and become rich with such invention.

The requisites are:

  • I can only travel back in time once, no way back to the present;
  • I can't bring anything with me, everything must be remembered by my average memory;
  • once I get back in time, I must be able to take advantage of my knowledge in a realistic manner to become rich (if you tell me to invent the cure for the bubonic plague I doubt I'd be able to do it);
  • There's no limit to the amount of knowledge and inventions I can bring with me, my average memory is the limit;

The solution that makes me richer will be awarded (possibly with the minimal effort)

  • $\begingroup$ Sounds entirely opinion based. But "Standard time travel question" : you bring something back, use it to change history ("invent" something someone else did) - didn't you just change everything and your birth, live and all the events in your world can now be different ? Simplest solution : bring back gold, buy property. $\endgroup$
    – StephenG
    Aug 10 '18 at 23:13
  • $\begingroup$ @StephenG I specify you can't bring back anything with you. I don't think it's a "standard" question. I don't see it more opnion based than most of the questions of this site $\endgroup$
    – Fez Vrasta
    Aug 10 '18 at 23:17
  • $\begingroup$ related if not duplicate question $\endgroup$ Aug 10 '18 at 23:49
  • $\begingroup$ This feels story-based or primarily opinion-based. Why wouldn't you follow the example of the movie Primer and use your knowledge to invest in the stock market? No changing of history (per se), no mess or fuss with the process of invention. Just seems simpler. $\endgroup$ Aug 11 '18 at 3:33
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    $\begingroup$ @StephenG: Probably the Terminator movies. They needed a reason why Arnie couldn't simply bring a death ray along $\endgroup$
    – nzaman
    Aug 11 '18 at 7:05

Go back to the relatively recent past.

Nothing keeps you from memorizing a few choice stock picks, or event winners of certain sporting events, or lottery picks either. Don't overdo the gambling, people will wonder why you win all of the time. But gambling is the fastest way to get seed money for capital-intensive ventures.

Use your knowledge of blockbuster movies to make them first. George Lucas is worth about 5 billion USD -- this is likely rich enough for your purposes. Best thing is you don't even need much expertise, others can do the work.

Also, inventing block-buster apps is about like inventing movies. If you were to invent MS-DOS, Visicalc, Lotus-123, etc. you will be more than rich enough too.

In short, there is no shortage of lucrative opportunities if you have the fore-knowledge of what works.

Being rich is no fun if you die from smallpox or TB, recent history is strongly recommended. Recent history has the advantage that you get to enjoy high-tech conveniences of modern life too.


LEDs are a simple enough device, inexpensive to manufacture, with broad enough applications to be extremely lucrative if you are the first person to invent them.

The struggle that I imagine you will have, though, is not the invention itself. It's the marketing. You're going to have to do some homework to find out who managed to get rich on their inventions in your target timeframe and try to follow their methods. Lots of people make great inventions and sell short because they suck at marketing.

If I wanted to get rich on a time machine, though, I would go to goodwill and buy a junk computer, then go back to 2009 and start mining bitcoin. Once you've got a few thousand bitcoin, you can decide whether to stop mining or leave your machine running in the basement of some university, but when you come back to the future you'll be quite wealthy. There are other good investments you could get into as well, like you could go back in time and buy stock in Nike before they got big, or go to the 60s and buy a yellowcab medallion and then come back to the early 2000s and sell it for a few million in profit.

Investing is also safer in terms of your impact on the timeline, and easier in terms of the necessary social/political skills. It's all luck for people with no time machine. You could also get into betting on horse races, for that matter.

  • 2
    $\begingroup$ In addition to the marketing, it's defending the patent, and actually producing something at a profit. It'd be easy enough to go back and invent the lightbulb, but it'd be hard work preventing Thomas Edison from driving you out of business. $\endgroup$
    – workerjoe
    Aug 10 '18 at 23:22
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    $\begingroup$ Edison was a shark, too. I wouldn't want to be on his bad side in the business world. $\endgroup$ Aug 10 '18 at 23:22
  • 2
    $\begingroup$ Maybe it'd be best to go back in time inventing a "process" instead of a "thing". For example, go back before Henry Ford and invent the assembly line. Or invent the Bessemer process for steelmaking, or the Pilkington process for glassmaking. $\endgroup$
    – workerjoe
    Aug 10 '18 at 23:25
  • $\begingroup$ Bitcoin in the early 90s? Initial release 9 January 2009 (9 years ago). If you are going to time-travel to make money, make sure your have your facts straight. $\endgroup$ Aug 10 '18 at 23:34
  • $\begingroup$ @GaryWalker Thanks for the correction! Edited to fix. $\endgroup$ Aug 10 '18 at 23:40

The time period is essential. Go back too far, and you will be tried and killed as a witch/warlock. Go back too soon, and you're just an average, every day Joe. If you go back to before the Industrial Revolution, you could become filthy rich:

  • Invent the assembly line, and sell the idea to Henry Ford (The easy way)

  • Invent the steam engine before 1712 (The extraordinarily profitable way, though a bit early)

  • Best of all, make the lightbulb (Beat Thomas Edison, and invent it in your first try)

The industrial revolution was a time of much revolutionizing, and you could quickly become rich since the Assembly Line, Steam Engine, and Lightbulb are all fairly easy to remember. Be the Elon Musk of the 18th/19th centuries


@boxcartenant 's idea inspired me, what if you bought stock in Microsoft, Google or Apple before they hit it big? What if you met Steve Jobs or Bill Gates? You'd probably learn from them and also probably (if you're good enough), sub-entrepreneur (what's the word again?) with them?

You'd probably learn a few things from the creator of the good stuff today, and also earn a ton just by investing and more by helping (if you're going for the lazy way just buy lotteries, then invest all of those money into big companies today.

There is a possibility that if you invest in the company they might "lose the urge to be new", causing them to go bankrupt, which leads to the incentive for investing on Apple, the company that wants to be the newest.

It is also possible to re-invent the best thing today, the one you are using right now, the computer, or the internet. You can study hard on computer science and create an entirely proprietary series of internet or computer 30 years or more before they were invented.

Another possibility that no one thought of yet, medicine. If you would invent penicillin (or something else) in the dawn of the black death, you'd be the Pope. More opportunities lies there.

So the best option is to combine and duplicate these three, since you're going to live there, invent the toilet and concrete, since you'd like playing, invent the iPad, then invest in Microsoft.

Find the time that has the most innovation you can invent before, that will not execute you as a wizard, and that is good enough for life (no black death).


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