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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.

6
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2answers
52 views

How would a legal system deal with random groundhog day events? [on hold]

I have seen similar questions about groundhog day but they were about either a single unique groundhog day or a permanent one. In this case, each day may or may not repeat. There are no limits so ...
43
votes
27answers
13k views

How could a time traveler have prevented climate change

Let's say a Moon colonist in the future has discovered an alien time machine. A small remnant of humanity still exists on colony worlds in the solar system, but due to runaway climate change, they are ...
-3
votes
7answers
249 views
+100

A Theory for Science-Fiction Time-Travel

From H.G. Wells onward, there have been many stories concerning the phenomenon of time-travel. Few of them provide a plausible mechanism. For my story I would like to put forward such a theory. We ...
1
vote
6answers
626 views

What would the economic impact of FTL time travel be? [on hold]

Okay, so we found exotic matter and can power our Alcubierre drive. It turns out though, such devices allow travel to the past. The Novikov self-consistency principle holds. My question is, in this ...
10
votes
1answer
215 views

Could the equator of a world be a closed-time like loop?

Most works of fiction have quite imaginative views of time travel. Mighty machines that teleport in time instead of space. Gaping portals in space that take you to another time. Mystical beings with a ...
1
vote
1answer
53 views

Superluminal signal to past (alien technology) [on hold]

With our current understanding of physics it is not possible to send anything into the past (although GR mathematically allows it). Could an intelligent alien species with a 100,000+ year head start ...
-2
votes
0answers
87 views

Can a time tunnel be constructed? [on hold]

As a Big fan of Irwin Allen's TIME TUNNEL, during the sixties could such a thing be possible , The size depicted I would think would be pretty accurate. as the power requirements would be massive .....
0
votes
1answer
136 views

What will it cost me to travel through Time? (Part 1: Travelling forwards in Time - Time Dilation)

There are many questions on Worldbuilding about what item(s) a time traveller should take back in time in order to alter past events or even simply to survive. There has never as far as I know been ...
19
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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 ...
4
votes
15answers
2k views

Why would time travel affect the body in any major way, especially damaging? [closed]

Obviously, I'm talking about sci-fi time-travel and not just being as time moves by, slowly but surely. Is there a reason one would actually bleed from any orifice? For any pain to occur? Dizziness? ...
1
vote
2answers
99 views

Maintaining assets during time jumps

I started to ask this question in the Writing SE, but realized that I want both a method and a mechanism, so decided that for the latter, I'd come over here. I'm building a novel where the MCs are ...
7
votes
4answers
215 views

How can a species of natural time-travelers have a meaningful society?

Consider a fantasy species of "natural" time travelers. To define some specifics: Relevant Rules While it is not effortless, this species can move against the "arrow of time" much as a human can ...
57
votes
14answers
15k views

What would be the impact of a modern programmer and laptop being dropped into World War II, possibly breaking Enigma?

I've always found the idea of intelligent every-man sent back in time using his knowledge of the future tech to realistically impact the past. The first time something like this came to my mind was ...
7
votes
11answers
547 views

How could a well-educated person hurled back 2000 years and able to communicate with the locals most influence progress?

If a well-educated man or woman (master's degree level of education) with 20 years of experience in a field of your choosing was hurled back in time 2000 or so years, how could they most influence the ...
18
votes
6answers
2k views

Would a person from the past be able to survive for a week in New York?

A person from the 15th century Europe, by way of an Assiti Shard, gets thrown forward in time to 21st century New York City. They are aware they're going someplace weird, because the shard manifests ...
3
votes
3answers
251 views

How to use and maintain assault rifles brought to the past

A group of time-traveling soldiers ends up in 15th century Europe. They have an arsenal of either AR's or SMG's and need to use them until their resources (ammo) run out. How can they maintain the ...
26
votes
22answers
8k views

A solution for the time-travel paradox - What could go wrong?

Time travel has been invented and it goes like this. You travel backwards in time at the same speed you normally travel forward. Everything is identical - you do all the actions the same but in ...
-1
votes
3answers
165 views

Backpack contents for a modern person stranded in the stone-age [closed]

A time-travel experiment sends a volunteer back to the stone age. The Stone Age begins with the first production of stone implements and ends with the first use of bronze. Since the chronological ...
21
votes
10answers
3k views

First innovation for time traveler to low-tech society [closed]

A time traveler goes back in time (one-way trip, and he does not get to choose the exact destination) to a low-tech society, similar to medieval Europe. His objective is to kickstart an industrial ...
0
votes
1answer
117 views

Sending Messages Back in Time [closed]

It's hundreds of years in the future, and it sucks. I want to send a message to the past using our advanced technology and warn them what to do and what not to do, so the future is better (or, ...
10
votes
2answers
334 views

What goes in, must come out - limitations of temporal displacement

I am plotting out a sci-fi setting, and trying to figure out the consequences of a non-conventional form of time travel. In the story, time travel has been achieved by means of temporal displacement....
5
votes
6answers
651 views

Reactions to a Young Time Traveller

My question is simple. What would people in England in 1700 think of a modern, history loving, 12-14 year old girl? This particular girl was a case of time travel gone wrong. A school trip meant to be ...
20
votes
17answers
3k views

Lost in the multiverse: how to find home?

You have an individual who can travel backwards and forwards in time. They normally maintain an observer status but occasionally a butterfly is stepped on. Because, home is where the heart is, how ...
19
votes
8answers
5k views

What services could a time traveller offer a medieval king? [closed]

A brilliant modern scientist/engineer has been sent back in time to medieval Europe (somewhere between 800 and 1100 CE). It would be very advantageous for him to have many friends among the various ...
10
votes
4answers
885 views

Santa is a time traveller. How does he not violate causality?

People wonder how Santa can deliver all his presents in one night. It's, simple: he's a master time traveller. (This post will form the base of a long series of questions). Here's how Santa's usual ...
207
votes
14answers
29k views

Is there a single historic event which could be changed to cause the USA to use SI units?

I am time traveller with aim to make world better. Last time I went to the past, all I heard was: "Kill Hitler!" So I went to the past and I must tell you, April 1945 was pretty loud in Berlin! ...
14
votes
3answers
2k views

Bringing potatoes to the middle ages

A time traveller wants to save medieval Europe from famines by introducing the potato. The plan is, on first sight, simple: Just bring potatoes back with a time machine, and convince people to ...
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 ...
38
votes
29answers
7k views

How can I explain that a time travelling apparatus moves itself through time but appears in the same location?

For the purposes of this question, let's ignore the causality issues of time travel itself. Suppose our hero, or an accomplice of our hero, has invented a time travelling apparatus. It works like ...
-2
votes
2answers
156 views

Plausible reason why a time machine would be built in a 1990s era sports car? [closed]

So let's say we have a hero and a heroine. The hero doesn't own a time machine, but the heroine does and she built her time machine from a modified 1990s era Japanese sports car. Time travel requires ...
0
votes
8answers
323 views

What can a bunch of American kids teach ancient Egyptians? [closed]

18 children (ages 2-14) travel from a small American town in 1995 to the year 1312 BCE in ancient Egypt. They stay with Jewish slaves in their village (the structure is more serfs than slaves) for 9 ...
-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 ...
2
votes
6answers
173 views

Apparel for a time traveler [closed]

Some context: You are traveling to somewhere temperate (55-85 Fahrenheit )in the past, at some random time, post 1000 BC, pre 1800 AD.You do not know where, save that it is in Europe, or a similar ...
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 ...
2
votes
2answers
110 views

Earth Time Periods: Choosing for a hidden lair in time [closed]

You are a former nuclear scientist who has researched in the field of fusion, who is in possession of a device that once activated will create a two-way portal into any time period on Earth. The time-...
7
votes
6answers
785 views

Time Travellers And The Roman Empire, Part 1: Transport and Control

I am a time traveller from the not so distant future. I have gone into the past to the Roman Empire (specifically the Nerva-Antonine period) and via -handwaving magical mumbo-technobabble- have become ...
-1
votes
4answers
210 views

Could guy with offline wikipedia (and solar charger) that was transported into middle ages conquer the world? [duplicate]

Exactly what is on the tin. Would offline wikipedia (such as phone with kiwix or wikireader) with means to charge it (portable solar charger) be enough for young person to conquer country and ...
12
votes
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 ...
2
votes
5answers
356 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 ...
11
votes
10answers
2k views

Live die repeat, and win: how do we fight an army that can reset time?

Commander WE NEED YOUR HELP Aliens invaded three days ago and they have been slaughtering us, but now we might have information to fight them. Many soldiers have died to bring you this information ...
62
votes
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 ...
21
votes
18answers
4k views

What's the ideal era for harvesting resources by an advanced society?

It's 2100-ish and we're experimenting on our new time travel device, or let's say time travel bunker. What we gathered of information so far are: We can't really go back in time, literally. Every ...
5
votes
2answers
365 views

How can I make this religion believing in “creating time traveling gods through science” believable?

I want to popularize the following or a similar belief. In many thousand years people will travel back in time to give us an afterlife, if we make it possible, by going the steps, that will lead to ...
-1
votes
1answer
100 views

Time traveller tasked with finding traces of past alien visits to Earth [closed]

My time traveler is tasked with finding information on previous visits to Earth of a potentially hostile alien civ. What sort of traces might aliens leave that could identify them? I'm thinking some ...
0
votes
3answers
161 views

Immediate differences between 1898-2018 [closed]

I have a story where two characters from 1898 apear in the Texas hillcounrty, on a disused ranch. Neither are familiar with ranches, and they come from vastly different socioeconomic backgrounds. What ...
5
votes
3answers
162 views

How to broadcast Earth's position to someone in the future?

Using current technology, what could I do to optimize the odds of being located by time-traveling humans a thousand years from now? The accuracy must be such that they could "transport" me out of a ...
9
votes
3answers
3k views

Will a modern time traveler survive diseases of the past?

Joe Schmo is your average college graduate who is suddenly transported back to medieval times, without time to prepare. From there the stories, and questions on this site, are all about how he can use ...
6
votes
7answers
2k views

What is the smallest action required to destroy all of reality? [closed]

Scenario: The most feared evil scientist in the world, Sinister Norman Van Deathtoyou, is on a mission to destroy everything. Humans, Earth, The Universe, even the very fabric of space and time. But, ...
8
votes
4answers
805 views

Victorian astronomer detecting artificial satellites

To make it short, time-space shenanigans transported everything in a 60 kilometers circumference around an old space-based particle collider to the year 1855. The particle collider was in ...
-1
votes
1answer
51 views

Moving someone along their timeline [closed]

If one would use something like the Time Stone from the MCU to move someone along their own timeline, would they have all of the memories that they would have made if they had lived out their lives ...