252

Sort of similar to the Great Filter theory, but applied to time travel technology.

top 50 comments
sorted by: hot top controversial new old
[-] db2@lemmy.world 62 points 1 month ago

Or they know better than to visit the violent primitives.

[-] lurch@sh.itjust.works 48 points 1 month ago* (last edited 1 month ago)

nah, the reason is: when you travel back in time, our galaxy, solar system and planet are in different absolute universal positions. so you end up alone in deep space and by the time the planet reaches your position the time you traveled back has passed, making it absolutely useless and life threatening.

[-] FreeLikeGNU@lemmy.world 29 points 1 month ago

Pretty sure there is no absolute universal position, everything in the universe being in motion relative to everything else as the universe expands, but that does not disprove your point anyways.

[-] WhoLooksHere@lemmy.world 18 points 1 month ago

The reason it doesn’t disprove it is because the assumption “time travel works” is really just saying, if we ignore some basic rules of physics, what happens to what’s left? It’s a nonesense premise to debate what is basically nothing more than science fiction.

Could the rules we know about the universe be wrong? Absolutely! But discovering those new rules is what will answer that question. Till then, we might as well try and say Harry Potter is just quantum mechanics.

load more comments (1 replies)
[-] bjoern_tantau@swg-empire.de 7 points 1 month ago

You can use the cosmic microwave background as a universal reference frame. Relative to that we move at about 370 km/s, depending on the time of the year.

load more comments (2 replies)
[-] MeatPilot@lemmy.world 10 points 1 month ago

This is a basic fact overlooked by almost every time travel sci-fi. We wouldn't just jump into a machine and poof be in the exact same location 1,000 years ago.

It would be more like trying to land a spaceship on a planet light years away, there would have to be calculations for position and gravity. All sorts of crap before you even solve the impossible problem of turning back the clock.

Also we'd first have to figure out how to travel faster than light to even hope to break the riddle of time travel.

As fun as it is to theorize time travel would be impossibly complex and probably devastating to try.

Imagine what an object would do with all those forces behind it suddenly slamming into a object moving much slower, it would be like a time bullet that would tear apart the planet and punch a hole in space. We would likely achieve a black hole and destroy all of earth before we could see what earth looked like 1,000 years ago.

[-] ech@lemm.ee 12 points 1 month ago* (last edited 1 month ago)

This is a basic fact overlooked by almost every time travel sci-fi. We wouldn’t just jump into a machine and poof be in the exact same location 1,000 years ago.

It would be more like trying to land a spaceship on a planet light years away, there would have to be calculations for position and gravity. All sorts of crap before you even solve the impossible problem of turning back the clock.

If the only reason you find the premise of traveling through time preposterous is that they didn't do the basic research to make it work, why not just assume they did? It's a fictional world. Just go with it.

load more comments (1 replies)
[-] Spacemanspliff@midwest.social 5 points 1 month ago

The only theory I've seen that really holds any water is time travel going forward by using a ftl loop.

[-] sbv@sh.itjust.works 6 points 1 month ago

Have you noticed the flashing light in the sky? It started last year. It gets a little brighter every night. I only used to notice it when I was out of town, but now I can see it in the city. It blinks pretty quickly, probably twice a second. Some blinks are longer than others. If you watch long enough, it repeats. Short. Short. Short. Long. Long. Long. Short. Short. Short.

load more comments (1 replies)
[-] starman@programming.dev 29 points 1 month ago* (last edited 1 month ago)

Maybe it's impossible to travel back in time?

[-] echodot@feddit.uk 13 points 1 month ago

If time travel is possible it'll probably be limited to the lifeline of the time machine itself. You cannot travel back in time to a point prior to the invention of the first time machine.

load more comments (1 replies)
[-] EddoWagt@feddit.nl 8 points 1 month ago

No that can't possibly be the reason

[-] TheRealKuni@lemmy.world 4 points 1 month ago

Time isn’t really a thing, right? It’s just the chain of cause and effect, tied inexorably with space. There is only ever the present, the ever-shifting now. The past is a remembered state, the future is merely possible states.

Cause and effect happens more slowly or quickly due to relativity, but it doesn’t go backwards.

(Note, I am not a physicist.)

load more comments (2 replies)
load more comments (1 replies)
[-] 3volver@lemmy.world 25 points 1 month ago

Time travel within the same universe is not possible, it is a fun fiction which is always contradictory in some way. The only time travel possible would be the one that William Gibson uses in The Peripheral. His idea is that every time you go back in time a new parallel universe is created, and it doesn't impact your current universe because of that.

My theory is that we're one of the most advanced species in our galaxy, and yet we still can't reach another solar system. The probability of intelligent life forming from unintelligent life is extremely unlikely, and we had life on Earth for a LONG time before humans evolved. Intelligent life is very difficult to form, you need the perfect conditions and perfect stressors over millions of years. Then on top of that intelligent life which can reach another solar system is even less likely.

There's life out there thinking the same thing right now:

load more comments (7 replies)
[-] Gigan@lemmy.world 23 points 1 month ago

Or it's because we don't have time machines yet. It's like making a phone call when you have the only phone in existence.

[-] Knuk@lemmy.world 13 points 1 month ago

Imagine creating the first functional time machine only to have a shitton of time travelling tourists appear in it the second you turn it on

[-] jol@discuss.tchncs.de 4 points 1 month ago

Exactly. We can still only send a single gel banana back in time until we invent proper time machines.

load more comments (1 replies)
[-] PhlubbaDubba@lemm.ee 18 points 1 month ago

I prefer the theory of "OMLY FORWARD!"

Basically, you can only travel forwards in time because going backwards violates causality

However

Because of the possible 4th dimensional geometry of the universe and what that means for how it behaves over deep time intervals, it could theoretically be possible to go so far forward you end up back in time.

This possibility relies on the accuracy of the theory of the bang and crunch cycle, which basically states that the universe is a bubble of infiniteness and that if you figure out how to ride out a big crunch and following big bang, you can just keep fast forwarding infinitely until random happenstance takes you far enough forward in time to a universe that is identical to ours except you're arriving to a point that is identical to one that was "back in time" from where you started.

It's probably one of the more depressing takes on time travel since it's impossible to ever go "home" but then again in that sense you've never returned to the home you left from in the morning, because the one you return to exists forward in time from where you left.

[-] Twofacetony@lemmy.world 11 points 1 month ago

There is a great Futurama episode that visualises this. The Late Philip J. Fry - Futurama S06E07

load more comments (1 replies)
[-] slazer2au@lemmy.world 14 points 1 month ago

I believe the only viable timeline is the one where time travel is never invented because if you create the machine to go back to prevent something happening then there is no need to create the time machine.

Which yes is an actual paradox

[-] joyjoy@lemm.ee 4 points 1 month ago

That's why the reason for inventing the time machine is "just in case"

[-] rockerface@lemm.ee 3 points 1 month ago

Unless the time machines end up being restricted in travel only to the times after they're built. Which would resolve the paradox

load more comments (2 replies)
load more comments (2 replies)
[-] cynar@lemmy.world 14 points 1 month ago

The universe seems to be keyed to disallow time travel. The speed of light limit, in relativity, is sat exactly at the limit where time travel would become possible. Conversely, quantum mechanics does allow for FTP transmission. What it doesn't allow is information to flow along those links. It's hit with a 0.5 error rate, which completely blocks FTP communication.

General relativity does allow for a few time travel options. However, these are sat well off in the sticks, where quantum relativity would dominate. Since we don't have such a theory yet, our predictions are likely wrong. Even within these theories, a time machine would require a "closed timelike curve". These can, in theory be made using several rapidly rotating black holes. Any ship traversing it, would never be able to leave before the time machine was built.

Basically, time travel is almost certainly blocked by our laws of physics. Any loopholes would be limited to the lifetime of the "machine" and would require stellar level engineering for even a few seconds of travel.

[-] Ephera@lemmy.ml 4 points 1 month ago

As I understand, the FTL "transmission" in quantum entanglement is equivalent to just ripping a photograph in half, sticking the halves into envelopes and sending one of them to Australia.

By measuring the envelope you kept, i.e. opening it and seeing which half is in it, you gain instant knowledge, what the other half in Australia is.
This is mostly useless for communication, though, because the person in Australia does not get this information instantly.

In the case of quantum entanglement, the photograph halves are a particle, which has decayed into two particles, each of which have kept a shared property, like a spin of -1 and +1 respectively.

load more comments (1 replies)
load more comments (10 replies)
[-] cobysev@lemmy.world 11 points 1 month ago* (last edited 1 month ago)

Back to the Future had an extremely convoluted time travel theory that didn't actually make sense, but one interesting idea they sparked is that you create branching timelines when you go back to the past. Meaning your present timeline remains unaltered, but you basically skip to a new reality when you time travel. Essentially, they claimed the multiverse exists and you travel across dimensions, not necessarily time, when you used the Delorean.

Maybe this is why we never meet time travelers. Because our current universe is an unaltered world and any time traveling that happens here just sends people to other universes instead of our established timeline.

This theory is kind of nightmare fuel when you consider Doc and Marty left Marty's girlfriend on her porch in a dark future and just expected her to be there when they "fixed" the timeline. Nah, bro. You just abandoned her in the darkest timeline. The girl you picked up was an alternate reality version of her.

*EDIT: Back to the Future, not Bank to the Future.

[-] WarmSoda@lemm.ee 9 points 1 month ago

Doc does draw that on the board, but the movie doesn't follow that logic. It's strictly a cause effect type of time travel.

[-] Auli@lemmy.ca 6 points 1 month ago

The movie doesn't really follow they though. Otherwise why did Marty start disappearing.

[-] cobysev@lemmy.world 5 points 1 month ago

That's why I said their time travel theory doesn't make sense. The movie doesn't even follow its own logic.

[-] UltraMagnus0001@lemmy.world 10 points 1 month ago

Isn't there some theory that says the reasons why we don't see advanced civilization is because they destroy themselves with technology.

[-] TheGiantKorean@lemmy.world 6 points 1 month ago

Yep. Look up the Great Filter theory.

[-] Sam_Bass@lemmy.world 10 points 1 month ago

Or the timeline they are from is not our timeline

[-] RizzRustbolt@lemmy.world 9 points 1 month ago

The future doesn't exist, and the past is inaccessible to our Temporality.

[-] kromem@lemmy.world 8 points 1 month ago

Or they're the things 99% of people are calling 'aliens.'

Why an interstellar species would travel light years to come to this pale blue dot in ships that don't really interfere and look like our own just a few hundred to thousand years more advanced is kind of hand waved away.

But if those sightings are in fact accurate, it sure seems like our narcissistic species would be pretty interested in our past selves once the tech existed.

[-] PhlubbaDubba@lemm.ee 3 points 1 month ago

If invincible has taught me anything, it's that the aliens are here because they want to fuck

load more comments (1 replies)
[-] theodewere@kbin.social 6 points 1 month ago

maybe they don't visit us because we never call or text

[-] AbouBenAdhem@lemmy.world 6 points 1 month ago* (last edited 1 month ago)

If you were a historian with a time machine doing original research for your doctoral dissertation, you’d probably prioritize visiting the most poorly-documented eras first—the Information Age would be at the very bottom of your list.

load more comments (1 replies)
[-] BartyDeCanter@lemmy.sdf.org 6 points 1 month ago

There was an interesting physics paper recently that suggested that time travel was possible, but you wouldn’t be able to travel to before when the machine was built. Of course, it also would require an impossibly huge amount on energy, but that’s a problem for the engineers.

[-] Kolanaki@yiffit.net 5 points 1 month ago* (last edited 1 month ago)

If time travel existed, why would anyone come to this time period where everything is fucked up?

And if the tech is regulated to stop altering the timeline, they could be here in disguise. Possibly literally invisible to us because they're only permitted to observe and not actually take part in anything. It could even be that time travel works like Paycheck and not The Time Machine, and you're just able to look into the future/past but not actual travel to it.

Or the branching timeline scenario in Back to the Future is the reality of things, so even if you went back in time to talk to yourself as a younger person, that happens in a totally different dimension than the one you were in when you yourself were a younger person.

[-] Auli@lemmy.ca 3 points 1 month ago

Everyone is mentioning branching timeline of back to the future but the movie never follows that. Marty's parents are not getting together he ceases to exist. Biff brings book back and Marty goes right to that timeline. The movie is just cause and effect.

load more comments (1 replies)
load more comments (1 replies)
[-] Maggoty@lemmy.world 4 points 1 month ago

Nah we've had them. We just lock them in mental hospitals.

[-] Agent641@lemmy.world 3 points 1 month ago

Just tryna find the 12 monkeys bruv

load more comments (1 replies)
[-] intensely_human@lemm.ee 4 points 1 month ago

It takes more energy to go further back in time.

Everyone just assumes time travel is frictionless, but that doesn’t make sense. You want to go back ten seconds? Couple AA batteries. Want to go back an hour? Nuclear fission required. Seven days into the past? Microwave electronic resonance craft. A year? Forget about it.

load more comments (2 replies)
[-] Nosavingthrow@lemmy.world 4 points 1 month ago

Listen, the only logical conclusion to stop time tavel fuckery is a cascading series of event that cause all time travelers to be killed before tbey discover time teavel, or otherwise foil the discovery. The result is a nice clean timeline. I know this to be true because that technology would NOT be used responsibly

[-] Vilian@lemmy.ca 3 points 1 month ago

or it's impossible lol, today physics and teories agree that time travels to the past is impossible, it's go against literally everything, or ours theories are worng, but well it's working to this day

load more comments
view more: next ›
this post was submitted on 10 Apr 2024
252 points (91.2% liked)

Showerthoughts

27813 readers
285 users here now

A "Showerthought" is a simple term used to describe the thoughts that pop into your head while you're doing everyday things like taking a shower, driving, or just daydreaming. The best ones are thoughts that many people can relate to and they find something funny or interesting in regular stuff.

Rules

founded 11 months ago
MODERATORS