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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.

62
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13answers
12k views

I travel back in time: how could I know when I landed?

Today a weird guy with a pointy hat offered me and my friends to play a game: We will all travel back in time, to a random date somewhen from the antiquity to modern times. We will have a limited ...
30
votes
13answers
3k views

With future knowledge, can I prevent the Columbian Exchange epidemics?

I have traveled back to the 15th century with the goal of facilitating the discovery of the Americas by the rest of the world without causing epidemics to wipe out 90% of the American population. How ...
2
votes
3answers
163 views

Theoretical: If you were to psychologically examine people that have time-traveled, what would you look for?

Let us say there is an adult male, adult female, a boy, and a girl. They experience time-travel. As a psychologist, what would you examine before and after the travel to ensure that psychologically, ...
1
vote
2answers
176 views

Extrapolating from the GPS network for time travel

One of the aspects of most sci fi time travel representations that I find most challenging for my suspension of disbelief is this idea of people travelling through time and not travelling through ...
-4
votes
3answers
98 views

“Moving” through time doesn't actually involve motion [closed]

In regards to the concept of time travel, physical travel isn't possible or necessary. "Going" to other points in time, one would actually remain in the same place, not actually travel through space. ...
13
votes
15answers
5k views

How might a Professor of Mathematics Change History?

A professor of mathematics is sent back in time to a post-Neolithic farming village. They accept him as their wise man, and he spends 30 years teaching them all he knows about mathematics until he ...
51
votes
46answers
18k views

Plausible reason why my time machine can only go back a certain amount of time?

So, I have built a Time-Traveling machine. It’s a prototype, and I’ve noticed a few kinks in the machine. If the control pad gets jammed in home mode, the universe will repeat the same day for all ...
1
vote
9answers
735 views

If time travel exists and there's only a timeline, how can a event assured to happen be avoided without breaking physical laws? [closed]

Let's begin with the premise of that type of time travel, the one in which no matter what you try, the past cannot be changed, if you tried to kill your grandfather you wouldn't be able to as much as ...
8
votes
6answers
824 views

Survival strategy for a time traveller in the Roman empire [closed]

I would like to know what would be the best strategy to survive and prosper in the roman empire for a time traveller? Let's say that the time traveller is a 30-year-old Italian from the XXI century ...
3
votes
6answers
458 views

How does a time travel paradox actually begins?

A while ago I was conceiving a story about a guy that actually creates a method for viable time travelling but gets stuck in a paradox after using the machine. The background story for this is that ...
1
vote
1answer
197 views

King Arthur in Connecticut [closed]

In the middle of a joust, King Arthur receives a severe blow to the head and is somehow transported in time and space to Connecticut in 1889. After some initial confusion and his capture by the local ...
42
votes
15answers
13k views

How does a time traveler prove he or she is from the near past?

Assume a college student from 2018 accidentally traveled to 2023. He is accidentally taken by an alien spaceship that travels close to the speed of light away from earth and then travels back. He is ...
87
votes
31answers
16k views

My time machine needs to know when it is

I've built a time machine and it works in unmanned testing... sorta. I tell it to go into the past, it disappears, and then comes back to the present. The problem is that it isn't terribly accurate. I ...
0
votes
1answer
102 views

Help with “2012 meets Groundhog's Day” Scenario [closed]

This is a looping-day time-travel plot akin to Groundhog's Day. There is a sudden global cataclysmic disaster taking place. This doomsday disaster is almost impossible to survive. Those who died ...
41
votes
28answers
10k views

Why buy tech from the future?

The Demonstration You're a rich, successful CEO/capitalist working in the electronics business. Your R&D division is exceptional and routinely fabs state of the art processors at bleeding edge ...
3
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4answers
142 views

Effect of time travel on the collectible market

Another spin on the recent question How would you bring wealth back to the past?, this one will attempt to look at the effect on collectibles. Almost by definitions, things are collectible because ...
21
votes
8answers
997 views

How could an inter-temporal banking system work?

(This question is meant to be an improvement and/or replacement for How would you bring wealth back to the past?, which some users have argued is off-topic for this group.) Imagine a future world in ...
51
votes
22answers
13k views

How would you bring wealth back to the past?

Edit: A few people have argued that this question is off-topic, and as I write this it looks like it will be closed soon. However, I have written a new (and hopefully better) version of the question ...
-1
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1answer
157 views

What to do for money while stuck back in the 17th century? [closed]

So, a group of three people were experimenting with a time machine, and were transported back to 17th century Salem. The male is wearing a red hoodie and some jeans, the female is wearing leggings and ...
-1
votes
2answers
121 views

How to make someone who can time travel fail at preventing the death of one of his friends? [closed]

In my world, there is a character who can space-time travel (he creates an alternate reality each time he travels). He doesn't have a good control over his power but he can still think where and when ...
-2
votes
4answers
270 views

Does this kind of time travel exist? [closed]

WARNING: If this question is off-topic or in any way a bad question for this site, please don't downvote it, but migrate it to where it belongs. I cannot find an adequate place for this question, but ...
4
votes
1answer
262 views

Time travel to the mid-1980's - how do you sneak into society and make a ton of money as fast as possible? [closed]

The scenario: You are from the distant future, and are trapped in a parallel universe in the mid-1980's. You cannot expose your true identity and your only resource is a hidden laboratory where you ...
3
votes
5answers
327 views

The Paradox Men - Cosmology

In Charles L Harness's 'The Paradox Men', a spaceship crashes on earth several years before it launches, having circumnavigated the universe faster than the speed of light. It is a good read, but I ...
2
votes
2answers
174 views

How would age change when crossing into an alternate universe? [closed]

For a project I'm working on, a pair of "immortal" characters end up crossing from their dimension (a fantasy world) into what could be described as the "real" world, and I'm considering aging them ...
5
votes
2answers
158 views

Is there any way to build a world with science-compliable time travel without disproving the Theory of Relativity?

I want to make a world similar to ours, with one additional feature: Time travel. There is no difference to me if its loop-based or infinite universe based. But there is a catch: The theory of ...
5
votes
3answers
167 views

Time travel parental DNA shenanigans

If you and your significant other traveled back in time 50 years, had a child (who gets citizenship of the fictional country in question due to being born there) and left the child with a trusted ...
0
votes
1answer
137 views

What happen to gravity if time is suddenly running backward? [closed]

From my naive understanding of Einstein theory of relativity: gravity is not a force but only a consequence of inertia in a world where mass deforms the space-time. Without time, no gravity is ...
6
votes
4answers
532 views

Would ancient people understand “I'm from the future?”

Time travel is a major staple is sci-fi. You just can't escape it. Sometimes the characters travel so far back, that if or when they tell locals that they are from the future, I'm skeptical that the ...
4
votes
5answers
297 views

What would a person want from the past version of himself? [closed]

Imagine a world, where technology allows to summon yourself from the past to your own body. Conditions: you can only transfer consciousness from the past and back, no body, no things; you are not ...
6
votes
2answers
270 views

Einstein-Rosen Bridge Worldgate time-gravity travel issue

In this mostly hard-science universe I am using a theoretical "Hyperstable Gateway" to travel between planet X and Y; The wormhole has a ~5m diameter, The "Bridge" itself is negligible and a physical ...
2
votes
5answers
357 views

What items can I trade for supplies in the 17th century?

A trio of characters are stuck in the past (1691, Salem), without any supplies, except for the clothes they are wearing and the items they have in their pockets. They don’t have any food, and their ...
73
votes
12answers
21k views

How would people in 17th century Salem react to modern day clothing

So I and two others are working on a time machine, and I accidentally press a wrong button and whoosh, all my friends and I are in 17th century Salem, Massachusetts. Nobody sees us appearing out of ...
12
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8answers
1k views

How to prove you're a time traveller from the (far) past

(Almost like this post but not quite the same - I've seen multiple how to prove you're from the far future but not one how to prove you're from the far past so figured it could be fun to think of a ...
1
vote
4answers
216 views

What could be a possible way to avoid the effects of time travel on the traveller? [closed]

Let me explain... you have a time traveler from the year 10,000. The traveler has a device that has all of recorded history up until 10,000 a.d. in it, like a text book to be read. If that traveler ...
41
votes
11answers
10k views

Would time travelling to the present be lethal to a person from the 1200s?

John Smith is a time traveller from the year 2018, he goes back in time to the year 1200 and in the process falls in love with a woman of that era. He doesn't want to abandon her so he decides to ...
5
votes
6answers
481 views

(Please Someone Explain) Is time travel using wormhole as portals possible logically?

I am working on a story and came up with a doubt regarding an explanation given for time travel using wormholes as portals. The below given is taken from Wikipedia link: https://en.m.wikipedia.org/...
2
votes
4answers
324 views

How broken would my jPhone be if I traveled back in time 24 hours?

I have a character who ends up jumping backwards in time by 24 hours. Essentially nothing else changes, but the character has their jPhone in their pocket at the time of the jump. How functional ...
1
vote
2answers
128 views

What reading material from the current day could revolutionize the past? [closed]

Basic Premise The story of a person going back in time, bringing with them material from the future is one that dates back at least as far as 1838. Sometimes, the character brings a boomstick. Other ...
1
vote
3answers
139 views

What mystery of history to solve first? [closed]

Let us assume humanity, in the near future, acquires the technology to look and listen into the past without being able to change any of it, but it is very complicated and even more expensive, so, for ...
10
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3answers
272 views

The Transferable Skills of Sociopathy

Executive Summary Thank you for considering Chronograph Talent Consulting for your talent acquisition needs. We select the best talent from all previous periods of human history and make them ...
-3
votes
3answers
308 views

Which modern technologies can I use to pass myself off as a God / Demi-god in the medieval era? [closed]

Alex has a time machine. Alex wants to be revered as a god, change human history and make everyone worship him as the reincarnation of said god. I decide to be a god of war and conquer a big part of ...
1
vote
4answers
254 views

If I travel through a worm hole some massive distance, lets say 6 billion light years, have I traveled in time? [closed]

I'm writing a sci-fi novel and I want it to be well founded in science but I'm a bit confused about time travel vs distance travel. Some have said that to travel great distances is really time travel. ...
30
votes
10answers
7k views

How do I manage memetic infection while time traveling?

Time travel works...just invented, by you. The tests prove it! After many conversations and significant planning, your epidemiologist significant other has approved your plans for time travel, ...
-1
votes
2answers
205 views

Effects of an uninvolved time traveller [closed]

This is part one of two related questions. Let us suppose that we have an expert in a a particular period of time, a person who is one of the world's foremost experts on the period. This person also ...
0
votes
1answer
112 views

Time travel wars [closed]

I am wondering how futuristic wars would play out if time travel was an available technology, sort of like the Time War in Doctor Who. assuming a galactic war where both sides are fairly evenly ...
-1
votes
4answers
112 views

Motives for preventing a generation ship from reaching its destination - but not destroy it [closed]

The home planet of a race is completely annihilated (hit by another planet or something), but they managed to launch a generation ship beforehand, and a few thousand people go on a century-long trip ...
6
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3answers
3k views

What is the probability of two people having two identical scars? [closed]

What is the probability of two people having the same scar on their body in the same spot and the same shape and the same backstory (drunk driver in a chevy '78) Could the scar be a viable form of ...
1
vote
5answers
206 views

What can I offer to talented people if I can't allow them to have anything? [closed]

In your not-so-distant future of the 25th century humanity finally found a solution to one of the biggest problems: can we travel back through time? Actually, yes we can. However, there is a big BUT: ...
3
votes
6answers
285 views

What knowledge or occupation today would be most useful if time-travelling back to the Middle Ages? [closed]

Note: I'm new to this site, and I'm aware that the rules say it's better to ask questions that can answered, not just discussed, so if it is better I could phrase my question this way instead: "Are ...
3
votes
5answers
250 views

Criminal law and backward time travel

Alright, this might sound pretty convoluted, but I would truly value an expert eye to help me with a very theoretical situation. I've been working on a science fiction novel where the whole world ...