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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.

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5answers
272 views

Where does the Temporal Protection Agency get its intel?

Imagine a world with time travel, got it? Good. Now imagine that time has multiple dimensions. Time has its OWN dimension of time, along which it can evolve. This is called hypertime, or "w" (As in w,...
1
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1answer
362 views

Which person who lived within the last 150 years would have made the most difference to the world today if they were killed at age 15? [closed]

A time traveller wants to create a parallel world, and they want it to be as different as possible, but have certain restrictions imposed on them. They must do this by killing a person, without ...
4
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2answers
839 views

Logically consistent FTL without time travel [duplicate]

If relativity holds, than faster-than-light travel would allow for time travel into the past. However, some claim that if all FTL travel used only one frame of reference, there could be no temporal ...
2
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5answers
225 views

How to affect history in a positive manner and reduce negative 'butterfly effects'?

Context: Short story about an antagonist who can travel backwards and forwards within time. Problem: Struggling to explain a large plot hole in the written world. If the antagonist can travel ...
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13answers
4k views

How could a time traveller change medieval history using only modern knowledge? [duplicate]

How could a time traveller from our era change the outcome of a medieval battle using only knowledge of history, geography and modern science? Lets suppose our time traveller is a learned person ...
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0answers
206 views

What would you send in 10 m³ to the medieval age, and how would you obtain it? [closed]

So my protagonist has received "future data" because of this he is sure that a space that is 10 meters cubed will be transported back in time to a medieval time and place outlined in the data. "future ...
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4answers
270 views

Which forward time travel is correct? [closed]

There are two types of time travel which are shown in movies. When you sit in time machine , in fraction of second you are in future.It is completely new world , and you know nothing about it. When ...
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6answers
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Wouldn't a spaceship traveling at luminal or near light speeds come back to find earth hundreds of years in the future

If a spaceship left earth traveling at near or at light speeds (that being possible in this situation) would they not when coming back to earth, arrive many years in the future due to Einstein's ...
-1
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1answer
109 views

Prevent stroke in time travel scenario [closed]

What can be done to prevent a deadly stroke of another person if the MC can time travelling back to 3 days before it. Situation: Time travel is single time only, and 3 days only. The victim is a ...
0
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6answers
261 views

Capitalising on a Time Loop

I recently just watched "The Edge of Tomorrow (2014)" starring Tom Cruise. Its major plot device of a timeloop really got me thinking for a story/plotline. Say we have good old average Joe. He one ...
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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 ...
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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 ...
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8answers
747 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
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4answers
343 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
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7answers
283 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
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4answers
299 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 ...
-2
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1answer
341 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
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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
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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
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1answer
167 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
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2answers
171 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....
30
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8answers
9k 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
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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
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4answers
298 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
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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
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6answers
415 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
436 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
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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
849 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 ...
14
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7answers
792 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
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9answers
4k 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 ...
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11answers
555 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?
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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, ...
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1answer
268 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
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3answers
207 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
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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
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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
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7answers
3k 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
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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
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3answers
188 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
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3answers
251 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
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2answers
718 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'...
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1answer
186 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 ...
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1answer
60 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
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1answer
140 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
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1answer
383 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
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3answers
523 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).
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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
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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 ...