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New Model Solves Grandfather Paradox
goldfishy writes "If you went back in time and met your teenage parents, you could not split them up and prevent your birth - even if you wanted to, a new quantum model has stated. Researchers speculate that time travel can occur within a kind of feedback loop where backwards movement is possible, but only in a way that is 'complementary' to the present. In theory, you could go back in time and meet your infant father but you could not kill him." From the article: "Quantum behaviour is governed by probabilities. Before something has actually been observed, there are a number of possibilities regarding its state. But once its state has been measured those possibilities shrink to one - uncertainty is eliminated."
I am my own grandfather!
Farnsworth: Oh, a lesson in not change history from Mr. I'm my own Grandpa!
Sounds like the Novikov self-consistency principle to me.
Please, for the good of Humanity, vote Obama.
"OK, McFly, here's the gun. If you can kill your own father and thus erase yourself from existence, we'll know the theory was wrong."
Lawrence Person (lawrencepersonh@gmailh.com (remove all "h"s to mail)
http://www.lawrenceperson.com/
In other words, even if you take a trip back in time with the specific intention of killing your father, so long as you know he is happily sitting in his chair when you leave him in the present, you can be sure that something will prevent you from murdering him in the past
This means that you cannot be killed when you go back in time, nor can you kill or destroy anything! That's just perfect!!
Go back in time and be able to observe, only... no ability to interact with anyone either... it should be kinda like ghosts... we go back in time and observe and be like ghosts in the sense that we cannot interact and change anything that has already happened but only observe!
Imagine the possibilities of history classes of the future... maybe there are already a lot of ghosts watching us right now... the future students studying history!!
"Clearly, the present never is changed by mischievous time-travellers: people don't suddenly fade into the ether because a rerun of events has prevented their births - that much is obvious."
That's not clear at all. If I went back in time and killed the baby George W Bush, it's like he would disappear in the middle of a speech. Rather the entire course of history branching from that moment would be changed, so that in the "present" no one would ever know GW had existed.
-Alex
How can that even be remotely possible? Anything and EVERYTHING (no matter how small or big of an event it is) will change SOMETHING in the future.
Sci-fi writers have had two main theories for a long time. Either you can go back in time and change things, or you can go back in time and "fulfill" the past you expireinced. Just because you have an influence on the past doesn't mean your influence didn't shape time into the way you remembered it.
Anyone who thinks any differently needs to go back to school.
Yes, because I'm sure these quantum physicists haven't spent any time in school...
By doing the nasty in the pasty.
---- El diablo esta en mis pantalones! Mire, mire!
The one thing that always bothered me about those time travel movies (besides the ridiculous timetravel part) like "Back To the Future", is that you wouldn't have to go to extremes to prevent your birth. All you would have to do is bump into your Mom or Dad to delay them for 1 second; that slight change in the timeline would guarantee that it would be a different sperm that won the race to impregnate your mom.
Power to the Peaceful
It could be happening all the time and you wouldn't be aware of it (by definition).
Sounds like bad fiction to me.Sounds like the techno-babble "justification" in the bad fiction.And the easiest way to not change it is for time travel to be impossible.If, for example, you knew a picture would be taken, you could reflect light from your body and appear in that picture, thereby altering the future.
So, travelling back in time, you cannot reflect light, and, by the same token, you cannot absorbe light.
And it just moves up from there for all other physical effects. Nothing touched, no air breathed, no light disturbed, nothing.
So, how would you even know you were in the past?
"Anyone else having difficulty imagining a scenario where it would be "impossible" to kill somebody?"
*cough* Bin Laden *cough*
Well, I, for one, will never enjoy a pasty ever again.
What this sounds like to me: If you have directly or indirectly observed something occur, then there is no uncertaincy of it occuring. If you haven't directly seen something happen or been informed that it happened, then it may not have happened. Why do we need scientists to tell us this?
Something I don't think a lot of people really grok is that the laws of physics are time symmetric (actually the full symmetry is CPT, charge+parity+time, an electron going back in time would be a positron for example) so the fundamental weirdness is why we perceive time to flow in one direction in the first place. That's why I've always loved Feynman's absorber theory and it's associated spin-off the transactional interpretation of quantum mechanics. Those theories don't discard the so-called "advanced" (that is, backwards in time)solutions and work out how in a universe with appropriate boundary conditions you get an arrow of time. The advanced solutions actually exist but because of the boundary conditions they cancel each other out except where they "count". So according to the theory, when you go to push an electron every other particle in the universe sends waves back in time in response to push back on the electron at the exact instant you push it! The advanced waves only manifest themselves as the normal radiation resistance we observe when accelerating charged particles. The transactional interpretation takes this line of thinking with regards to the collaspe of the wave function. When one particle of a two particle entangled system wave function collapses it sends an advance wave back in time to collapse the wave function of the other particle. So in the EPR experiment there is no instanteous "spooky action at a distance" but travel exactly at the speed of light but in the opposite direction in time.
Actually, philosophers have had the theories, but time-travel sci-fi is, like most sci-fi, just a futuristic take on one philosophical idea or another.
:p.
The "new" model is actually called the "B theory" of time and isn't new at all (although this scientific explanation of it is I guess). The B theory is that every instance in time exists somewhere and it is always "now" in that instance, so there is no real past, present or future. In the B theory if you were to go back in time you would merely fulfil the events that happen in that instance of time, always as the way they were intended.
So if you went back in an attempt to kill the parents of the bully who harassed you in school you would find out that your attempts failed, and that they didn't change your "present" at all. In fact, they would have helped created your present. A good example of this theory in effect is the sci-fi series "Andromeda", which follows the B theory of time in its time-travel episodes. A more well known example is the movie 12 Monkeys.
Star Trek on the other hand follows the multiple futures theory, whereby if you go back in time and change something you actually from that point on move down a different branch of time into an alternate future. The Butterfly Effect is another movie example of this.
The problem with the B theory of time is that it requires a deterministic universe, which is an unpleasant who isn't a materialist (ie. you believe you're made up of more than just matter). Of course the alternate timeline theory also has its own problems in that regard, wherein if you can exist in multiple timelines then which one is really you and where is your soul? If you're a materialist then no worries
My own theory on the matter is that time is nothing more than a human construct. Matter changes, and one change takes place before another, and we measure the order in which these changes occur and call that 'time'.
Ahhh, someone who's willing to ask. :) Thanks. :)
While trying to avoid sounding like a complete lunitic, I'll try to explain the best I can. I'm no expert in paranormal events, so some of my phrasing may be a bit off. I was corrected on my experience of "Deja Vu" a few months ago, being told it's really "Precognition".
I was told when I was a kid that if I live through an event a second time, where I'm sure it couldn't have happened before, it was a "Deja Vu". This was clarified by someone more into paranormal phenomena to be a precognition. A deja vu is where you've lived it once, and you're living it again, even though you probably weren't able to have lived it once before. Use the example from the Matrix, where he sees a black cat run by, and then turns to see the same black can run by the same way again.
My precognitions usually happen years before the real event. They come in dreams. Usually they're very clear events, as viewed from my own eyes. Hollywood never portrays them like that, usually to show the stars involved in the scenes.
The most notable one was a conversation I had with 4 complete strangers. I went to a city I hadn't been to before, with a new friend. We met 4 of his friends there, and through the evening, we were having a conversation. We ended up in a library, and for 10 seconds through the conversation, I knew exactly what everyone was to say. At the point where I was suppose to say something, I didn't say a word. By not saying my part, the next person to speak didn't say anything, because I had changed the chain of events. They continued talking, it was just that it changed subtly.
Another changed event was visiting a strange house as a child. We went to a house, and I asked to play downstairs. I named very specific details of the downstairs of the house, because I **KNEW** I had been there before. They corrected me in that I had never been there before, because they had just moved in, but my details of the basement were absolutely correct, including an item of furnature which was left there by the previous owner. I may have changed this event by mentioning it too early, or it may have been changed by someone else changing plans.
My precognitions come more frequently when "something" is going to happen. The precognitions never have anything to do with the event that is going to happen, they're just like warnings that it will happen. The event isn't necessarly important to me, about half the time they are. I may get precognitions several times a day when the event is coming close. After the event, they can completely go away for a while. Sometimes it's weeks, sometimes it's years.
I can usually remember when the dreams are from. Usually they don't make sense at all, because of the time that I have the vision. I pass them off as a weird dream, until it really happens.
For example, I was dating this really nice girl. I dated her for years. While I was dating her, I had this dream. I was with this other girl in my car. This was a nice car, which at the time I didn't have anything like. I was at a particular intersection in a city I had never been in. I was messing with the air conditioning controls, because this girlfriend had changed something while I was driving. She was also talking on a cell phone to my ex-girlfriend (the girl I was dating when I had the dream), and their conversation was exactly from the dream.
When I had the precognition, I didn't see the girlfriend in the dream, because I was looking out at the traffic, which was a very specific part of the precognition. I didn't know what she'd look like, and I didn't realize what it was until it all happened. That dream was about 4 years previous to the event.
I spoke with someone who does remote viewing professionally. He's described some of his work. One that he told me about was an event that he was asked to view where something important to the investigat
Serious? Seriousness is well above my pay grade.
Why do we need scientists to tell us this?
/. saying "I could have told you that, who's paying these guys?" And all it really is, is that there was actual good scientific research going on, and the press got ahold of the simplest sound bite they could and presented THAT. There's usually a lot more than meets the eye.
Because this is a horribly simplified and popularized version of actual scientific work. It happens all the time: you hear "Study says: People would be happier if they chose jobs they liked." Everyone posts to