this post was submitted on 11 Jul 2025
52 points (91.9% liked)

No Stupid Questions

42250 readers
782 users here now

No such thing. Ask away!

!nostupidquestions is a community dedicated to being helpful and answering each others' questions on various topics.

The rules for posting and commenting, besides the rules defined here for lemmy.world, are as follows:

Rules (interactive)


Rule 1- All posts must be legitimate questions. All post titles must include a question.

All posts must be legitimate questions, and all post titles must include a question. Questions that are joke or trolling questions, memes, song lyrics as title, etc. are not allowed here. See Rule 6 for all exceptions.



Rule 2- Your question subject cannot be illegal or NSFW material.

Your question subject cannot be illegal or NSFW material. You will be warned first, banned second.



Rule 3- Do not seek mental, medical and professional help here.

Do not seek mental, medical and professional help here. Breaking this rule will not get you or your post removed, but it will put you at risk, and possibly in danger.



Rule 4- No self promotion or upvote-farming of any kind.

That's it.



Rule 5- No baiting or sealioning or promoting an agenda.

Questions which, instead of being of an innocuous nature, are specifically intended (based on reports and in the opinion of our crack moderation team) to bait users into ideological wars on charged political topics will be removed and the authors warned - or banned - depending on severity.



Rule 6- Regarding META posts and joke questions.

Provided it is about the community itself, you may post non-question posts using the [META] tag on your post title.

On fridays, you are allowed to post meme and troll questions, on the condition that it's in text format only, and conforms with our other rules. These posts MUST include the [NSQ Friday] tag in their title.

If you post a serious question on friday and are looking only for legitimate answers, then please include the [Serious] tag on your post. Irrelevant replies will then be removed by moderators.



Rule 7- You can't intentionally annoy, mock, or harass other members.

If you intentionally annoy, mock, harass, or discriminate against any individual member, you will be removed.

Likewise, if you are a member, sympathiser or a resemblant of a movement that is known to largely hate, mock, discriminate against, and/or want to take lives of a group of people, and you were provably vocal about your hate, then you will be banned on sight.



Rule 8- All comments should try to stay relevant to their parent content.



Rule 9- Reposts from other platforms are not allowed.

Let everyone have their own content.



Rule 10- Majority of bots aren't allowed to participate here. This includes using AI responses and summaries.



Credits

Our breathtaking icon was bestowed upon us by @Cevilia!

The greatest banner of all time: by @TheOneWithTheHair!

founded 2 years ago
MODERATORS
 

If you had a machine that created a window through which you could see the future, and in the future you wrote down the winning lottery numbers and relayed that information to your present self before that lottery number was drawn.

However, in your present selfs excitement, you turn off the machine before your future self wrote the winning lottery numbers into it for your past self.

What would happen?

you are viewing a single comment's thread
view the rest of the comments
[โ€“] Zonetrooper@lemmy.world 2 points 1 day ago* (last edited 1 day ago) (1 children)

Disclaimer, I am not a physicist, just a guy with interest in sci-fi, science, and too much free time.

is their any theory centered around our frame of reference having a past but not a future?

So, the answer is, yes, this is actually kind of a common theory on how time actually works. Maybe.

This has to do with physics, and the fact that no two observers have the same perfect frame of reference. For most of us humans, our frames of reference are close enough to be identical on a day-to-day basis. It's even close enough for (most) science. But it's not true on a perfect level. For instance, special relativity says that time passes differently for objects in motion; GPS satellites have to correct for the fact that their onboard clocks are experience "slower" time than us observers on Earth. Even astronauts "lose" about ~1/100th of a second for every year spent on the ISS.

What's this got to do with the future not existing, though?

So we know no two observers have a perfectly identical frame of reference - there is no objective "truth" of when something occurred. Cool. Now what? Well, what we can talk about is historic light cones. Because the speed of light in a vacuum is a universal constant, we can determine how far from you a photon departing your actions would travel. Places that photon would reach at any given point in time following your action are said to be within your historic light cone, and in common parlance, the past. The boundary of how far that photon is reaching at any given moment is, from your frame of reference, "the present". But since nothing can exceed the speed of light, it is impossible for an observer to view beyond the present, into the future.

The catch, of course, is reference frames. You used a plural - "our frame of reference", "we're blazing a trail forward" - but the reality is that each of us has a minutely different reference frame and is blazing a minutely different trail. Again, for almost any day-to-day purposes this is irrelevant... but there are certain scientific experiments which exploit or even rely on this absence of reference frame.

Cool, what about time travel again?

In my first comment above, I mentioned something called closed timelike curves. Those are an actual thing: By severely bending spacetime, you can theoretically cause a photon to "curve" around and end up at the same point in time it was produced, now in its subjective past, while mathematically not violating quantum physics.

This is where things get kind of freaky and headachy; if a photon can be sent into its subjective past, doesn't that imply a future now existing, in which that photon will be generated? The answer is, not in the frame of reference of that particular photon. A historic light cone of that photon being generated, now in that photon's future, still exists; but that photon is now generating a new, detached lightcone...

Like I said, headachy. I also have to emphasize that while the math holds up, there's ample reason to believe CTCs don't exist, chief among them that our mathematical understanding of quantum physics may still be imperfect.


tl;dr: Yes, absence of reference frames means that each distinct observer is blazing their own trail, which spreads into the "past" at the speed of light. The future, exceeding the speed of light, is unobservable. This framework does provide a mathematical concept of how you could send something into your subjective past, but such a means is still theoretical at best.

That was fascinating to read, thank you!