Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [time-travel]

For questions relating to travel in time. Such travel often involves FTL travel; consider also using the [tag:faster-than-light] tag.

11
votes
3answers
1k views

How can I convince the Internet public at large that I am from the future?

We all know that modern internet forum users, unlike your average social media frequenter, are skeptical and they often dismiss extraordinary claims as fabrications. We all also know that these ...
-2
votes
1answer
148 views

Time travel only possible when we go behond light's speed [closed]

Friends here are my views on Time Travel: I think with every past second the light rays of that particular second travel in a different dimension & therefore the light rays of next second travels ...
7
votes
8answers
718 views

How can you possibly stop a person who can reload life? [closed]

A random human, Bo, can reload life; whenever he dies, he simply loads back to before he was dead; whenever we catch him, he loads to before we catch him. Bo has been causing some problems and we need ...
4
votes
4answers
336 views

What would be the “scientific” explanation for having memories from a parallel universe?

This world is like ours but time travel is possible. The character and others have made time travelling in their past to change things but did not think about the consequences, so they created ...
8
votes
7answers
272 views

Staggering “Now” Among Many World Multiverses?

Regarding the Many World Multiverse, everything I've been reading (and searched on SE) seems to assume that each (parallel) universe is, at this moment, the same age. For my story, I need this to not ...
4
votes
4answers
292 views

What happens to time orphans in mutable history on further time travel?

With time travel and the Grandfather Paradox (where you go back in time and kill your own ancestors), a fiction author can define whatever rules make the story work, but ideally, those rules are ...
-1
votes
1answer
328 views

Where are the tourists from the future? [closed]

I would like to propose the following situation: (1) time travel to the past is possible, (2) there is only one version of the past, one timeline and (3) the past (or the future) cannot be changed. If ...
28
votes
5answers
2k views

How to test a time machine?

Eureka! I have a time machine in my garage and it works. I put an apple in it, close the door, set the timer, open the door to an empty machine, wait five minutes and the apple reappears. (Still ...
33
votes
18answers
7k views

Can time travel make us rich through trading, and is this a problem?

At different points in history, commodities have been at different levels of supply, and therefore have been at different prices. One good might be valuable in the present while another is nearly ...
0
votes
1answer
166 views

What would the world look like through the eyes of a superspeed superhero? [closed]

If a superspeedster like the Flash existed, while they moved at superspeed their mind must be capable of comprehending the world they are moving through. What will the world look like to them? Will ...
0
votes
2answers
169 views

How to run for president of the United States with time machine? [closed]

A mad scientist was murdered and his invention was stolen, it is a disposable time machine which can instantaneously allow any person to swap minds flawlessly and painlessly with anybody from the past....
28
votes
7answers
8k views

How far back in time can I go before people stop accepting my money from the future?

Lets say I go back in time with a wallet full of, say, 150 dollars worth of bills. How far can I be sent back before I reach a point where I'm unlikely to be able to use my money because it looks too ...
17
votes
3answers
3k views

How long could an operational Virginia-class sub survive in the Jurassic sea?

A nuclear attack submarine carrying a crew of, at least, a hundred people went missing in the North Atlantic Ocean, its last known location was the Bermuda Triangle where ships and planes have ...
5
votes
4answers
295 views

How do I explain checkpoints without magic?

Checkpoints have been a staple of video games for decades and are almost as old as video games themselves, but how? These little tiny features have made a huge difference in the way we play games, ...
5
votes
10answers
1k views

How to prevent time travelers from developing god complex?

Year 2077 C.E. someone invented a one way time travel into the past safely, the problem is that anyone can replicate the method with ease due to the proliferation of All-In-1 Advanced 3D printers and ...
7
votes
6answers
410 views

How would floating point numbers be affecting space and time travel in future?

Each technology, that is evolving, begins with simple piece of programming code that starts with variables of certain data types. It is interesting to note that many calculative and computing ...
5
votes
6answers
431 views

How well would a human from 50,000 years ago adapt to modern day life? [closed]

If you were to take a person from 50,000 years ago and plop them down in the middle of 2016, how well will they adapt to modern life? Would it be possible for them to learn how to use our technology ...
22
votes
14answers
5k views

What change in history would I have to make to stop Christmas from happening?

My antagonist, a typical Scrooge-like character, has travelled back in time to stop Christmas from ever becoming celebrated. What is the smallest change I could make to history to stop Christmas from ...
9
votes
4answers
797 views

What would happen if I showed the Vikings advanced technology?

Today, I answered a question in an essay which related to time travel and what I would do if I could go back to a historical period. This got me thinking, and I came up with a hypothetical scenario in ...
13
votes
7answers
641 views

Helping the Soviets to win the race to the moon

Because of an error in the interpretation of the Mayan calendar I just discovered, I know now that Earth will be destroyed on March 13, 2021 at 11 o'clock in the morning, time zone of Palenque. I ...
-1
votes
1answer
112 views

What happens when we travel into the past? [closed]

I read that when we travel into the past past we actually travel to a parallel universe. What is the reason? Who said that?
19
votes
8answers
3k views

How do you prevent causal loops from happening with the Novikov self-consistency principle?

The Novikov self-consistency principle states that all changes that occur due to time travel into the past were always part of history, and so the course of events is not changed. While this is useful ...
9
votes
11answers
547 views

How to let people know you are stranded in time?

You've traveled back in time 65 million years, with no way to return. What evidence can you leave to ensure future humans will know of your existence?
60
votes
14answers
12k views

How to find out a year I'm in?

Let's assume I can travel in a space-time on Earth. Every time I jump I get to almost the same place, but in different past time relative to the first jump: it solves the problem of planet rotation, ...
-2
votes
1answer
248 views

How to destroy a parallel timeline? [closed]

In a world similar to ours, mankind has invented time traveling technology since hundreds of years ago. Initially, it was very costly and only conducted for scientific purposes but nowadays it's ...
5
votes
3answers
194 views

Build a vactrain time-machine

Context According to relativity law, it is possible to travel into the future approaching the speed of light. For the 2nd Newton's Law of motion, in absence of friction (or opposite force), we can ...
8
votes
6answers
2k views

Airliner takes off from JFK in 1966, gets stuck in time warp and lands in London in 2016 [closed]

If an airliner disappeared in 1966 and landed in London 50 years later, without anybody on board being aware that they had been 'lost', what difficulties would they face? I'm thinking that when the ...
16
votes
8answers
4k views

In a world with time travel, could one change the present by changing the future?

The question I have is about the details of cause and effect occurring out of standard temporal order. Distilling it down to a single scenario: Consider two people, Alice and Bob, in a closed room. ...
5
votes
7answers
2k views

If time travel was to be invented somewhere in the future, wouldn't all history be filled with time travellers? [closed]

Say that at some point of history in the far future, time travel becomes possible. That means that from then on anybody could travel in time. If that is possible, doesn't this mean that our present, ...
0
votes
0answers
80 views

Time Travel vs Conservation of matter and energy [duplicate]

If you were to go back in time, how would you account for the extra matter and energy in the Universe you have created? (the laws of Matter and Energy Conservation). Would not every atom in your body, ...
1
vote
3answers
187 views

time travel paradox [closed]

If you were to go back in time, how would you account for the extra mater in the Universe? Would not every atom in your body, the oxygen in your lungs and all that you brought with you, already exist ...
5
votes
3answers
243 views

How to design puzzles for an ancient period in Earth history?

I'm writing a Earth history time travel story, and the main character needs to solve puzzles from each time period he visits. I'm going very far back in history and I'm concerned about being able to ...
7
votes
2answers
717 views

Intellectual Property infringement

My name is George. I am the true creator of peanut butter. Since my discovery, I fell into a time vortex that landed me in 2014 where I have found that my old rival has taken credit for my idea. I'...
-6
votes
1answer
183 views

How to “milk” a Rex? [closed]

Continue from https://worldbuilding.stackexchange.com/questions/59315/how-to-defend-a-phone-booth-against-horde-of-zombified-carnivorous-dinosaurs. (This question concludes the time traveling phone ...
-2
votes
1answer
59 views

How to search and rescue missing person in the late Cretaceous? [closed]

Continue from How to tour Cretaceous Period on economic class?. Say one of my VVIP client got trapped alone in the late Cretaceous Period, and his family wish to recover him alive in one piece. I ...
3
votes
1answer
136 views

How to tour Cretaceous Period on economic class?

Supposedly I found a phone booth that can transport user 65 millions years into the past (location fixed at Chixulub just 30 minutes before the announcement of the arrival of the impactor. Points to ...
1
vote
1answer
380 views

Would a time-travelling blockchain destroy a cryptocurrency?

The story So Bob, the multi-billionaire, is a wealthy person today but in a not so far away future he will lose quite a chunk of his wealth and become just an ordinary millionaire. Future Bob is no ...
5
votes
3answers
493 views

A modern-day scientist travels back in time to Nazi Germany [closed]

What can he do with his knowledge of 21st century science and engineering to shift the tides of war in Germany's favor? Saying "help them build a nuke" isn't allowed (because it's way too obvious).
17
votes
12answers
6k views

A power source that would last a REALLY long time

OK, so let's say Jim and Bob have a time machine. It's a large construct: Server rooms with quite a bit of human knowledge in them power generators some areas to grow food a voice activated terminal ...
49
votes
8answers
5k views

Stopping time, by speeding it up inside a bubble

Imagine I have a device that can stop time for the person who holds it (similar to Bernard's Watch). This device works in a very specific way - it creates a bubble around the user (just large enough ...
2
votes
2answers
551 views

How would I NOT get rich by going back in time and telling myself about Google? [closed]

Suppose someone gets a time machine, somehow, and decides to make some extra cash the usual way. S/he goes back in time to 1997 and tells his/her Past Self about Google. Under the following ...
8
votes
5answers
542 views

As a time traveler, how would I see quantum randomness change history?

Suppose I have a time-traveling DeLorean (of all things), and I've used it to travel back to 1955. But then I ran out of juice. Fortunately, I just happen to know that a certain clock tower will be ...
-1
votes
1answer
140 views

About time travelling, multiply yourself

About time travelling, if I go back one year, find my past self, wait until a little before I first went back in time (11 months and 29 days) and both of us go back, we keep repeating this until we ...
5
votes
4answers
411 views

How far in the past could unprepared humans survive?

A small late medieval county, consisting of a very small town, a small castle, and a couple of surrounding small villages suddenly and inexplicably gets transported into the past. It's not a spherical ...
43
votes
21answers
12k views

How much could a time traveler earn from selling 2016 tech having traveled back to 2000?

Joe, the average Worldbuilder accidentally slips through time sixteen years back. From September 11, 2016 to September 11, 2000. He gave saving the World Trade Center a thought, but then he decided to ...
6
votes
4answers
575 views

How to prove you're not from the future?

Imagine this situation: One warm night of 1890, you go home from a pub. You pass a creepy house. In the half-open door, you see the outline of a machine. You go in, and open the lights. You see a big ...
2
votes
5answers
405 views

Travel (how far?) into the future using a black hole and light-speed space craft?

A person is traveling in a space craft that was designed and built by sufficiently advanced aliens. This space craft left from Earth and is capable of traveling infinitely close to the speed of light. ...
20
votes
17answers
8k views

Avoiding preventing your own birth in a time travel paradox?

Assume a world with no multiverse theory, just a single unbroken timeline. If you were to go back in time to the town your parents lived in on day of your conception, the air displacement due to your ...
27
votes
14answers
5k views

Can a single time travelling person prevent the World Trade Center attacks? [closed]

You are a fellow Worldbuilder and while travelling by train, you fall asleep. Next time you wake up you realize you woke up at Grand Central train station. You quickly realize that you traveled not ...
2
votes
4answers
364 views

If I travelled to 1979 how easy would it be to become the Worlds richest person? [closed]

Lets say I was teleported back in time as an healthy average intelligence but street smart 21 year old reconstituted in NYC naked in Central Park at 23.59 hours on December 31st 1979. How easy would ...