Time Traveling - Impossible?

[lemur]

The approach is just yours, and doesn't makes sense to me. The sci-fi ones not only makes sense to me, but are used more often which means more people agree on it as well.

The whole point of fiction is that it's fiction. You're trying to unify all sci-fi fiction to follow the same fictional rules? Why would you do that? You're entitled to your opinion that you dislike my idea but why would you attempt to criticize it on the basis of majority opinion? It's like saying that I'm wrong if I color a unicorn red because most people color them white or purple, so that makes more sense as a unicorn color. Unicorns are fictional! They don't have a natural color. I can't imagine how harsh you'd be on a preschooler for coloring a zebra with green and orange stripes.

Edited February 6, 2011 by lemur

[steevey]

The whole point of fiction is that it's fiction. You're trying to unify all sci-fi fiction to follow the same fictional rules? Why would you do that? You're entitled to your opinion that you dislike my idea but why would you attempt to criticize it on the basis of majority opinion? It's like saying that I'm wrong if I color a unicorn red because most people color them white or purple, so that makes more sense as a unicorn color. Unicorns are fictional! They don't have a natural color. I can't imagine how harsh you'd be on a preschooler for coloring a zebra with green and orange stripes.

 

I'm not saying your wrong, I'm saying to me, your theory doesn't make sense, and that the reason I brought up contemporary sci-fi time travel is because they make sense to me. Since yours doesn't make sense to me, there's no way I can agree with it or disagree with it, and bring up something that you probably know.

Edited February 6, 2011 by steevey

[lemur]

I'm not saying your wrong, I'm saying to me, your theory doesn't make sense, and that the reason I brought up contemporary sci-fi time travel is because they make sense to me. Since yours doesn't make sense to me, there's no way I can agree with it or disagree with it, and bring up something that you probably know.

Ok, that makes more sense. Thanks for explaining it that way. Here's the thing about our conflicting ideas, though: if electrons could totally disappear and re-appear after 100 years time, what would cause them to remain in a certain position in a gravity field or even retain inertia? Would the electrons be absent yet somehow continue to respond to gravitational force? Would their place in spacetime continue according to its inertia without them actually being present as matter?

[steevey]

Ok, that makes more sense. Thanks for explaining it that way. Here's the thing about our conflicting ideas, though: if electrons could totally disappear and re-appear after 100 years time, what would cause them to remain in a certain position in a gravity field or even retain inertia? W

 

No, its probability. The gravity and other forces would hold the electron's most probable place to exist in a specific region of space, so the electron would usually pop there for 100 years +. Electrons CAN appear in other places than their most probable place though, but just not often.

Edited February 8, 2011 by steevey

[lemur]

No, its probability. The gravity and other forces would hold the electron's most probable place to exist in a specific region of space, so the electron would usually pop there for 100 years +. Electrons CAN appear in other places than their most probable place though, but just not often.

But how does the probability-area maintain momentum vis-a-vis other particles? E.g. does it continue to be affected by the protons when it "blinks?" This is nonsensical discussion, I think because for an electron or multiple electrons to blink for 100 years, that would imply that macro-motion of super-atomic objects could have a shorter duration than electron motion, which seems physically impossible just because the one is emergent from the other, no?

[steevey]

But how does the probability-area maintain momentum vis-a-vis other particles? E.g. does it continue to be affected by the protons when it "blinks?" This is nonsensical discussion, I think because for an electron or multiple electrons to blink for 100 years, that would imply that macro-motion of super-atomic objects could have a shorter duration than electron motion, which seems physically impossible just because the one is emergent from the other, no?

 

Ok, even though an electron (and all other particles) is a wave of existence, its still a thing. It's still a solid thing that makes up the world around you. It's still classically effected by forces like gravity and charge. The "blinking" thing just comes from observing and determining the exact properties of it for the time you observe it, but even at that point, it is still a wave in its entirety.

Edited February 9, 2011 by steevey

[lemur]

Ok, even though an electron (and all other particles) is a wave of existence, its still a thing. It's still a solid thing that makes up the world around you. It's still classically effected by forces like gravity and charge. The "blinking" thing just comes from observing and determining the exact properties of it for the time you observe it, but even at that point, it is still a wave in its entirety.

Then how could it even be imagined to facilitate time-travel?

 

 

 

[steevey]

Then how could it even be imagined to facilitate time-travel?

 

 

 

Because people didn't know about the wave mechanics model and that there being an actual "fabric" of space isn't proven to exist.

 

But, there is something almost as cool under development which is quantum teleportation. I don't know exactly what scientists are doing in it, but they are I think trying to send information with 0 lag using entanglement and achieve greater processing capabilities using the wave properties of particles. The ultimate thing in that field though, I think is to travel to anywhere in the universe instantaneously whenever you want.

Edited February 10, 2011 by steevey

[random]

wow this post helped me understand a lot

 

 

Not me buddy it's all Greek to me, I think I'll stick to Time travel is impossible with today's technology but nothing is impossible indefinitely, That's the extent of my intelligence in this area. Time after time as technology develops we find a way to accomplish.

[Riot]

Not impossible. Sub atomic particles under theoretical certain conditions can become slower than the speed of light which would cause a "reverse" in time. Although, it does not change time because time is constant; but the speed.

Edited April 6, 2011 by Riot

[iAmSchrodinger'sCAT]

Search up the arrow of time. I had a hard time wrapping my mind over this concept too. But arrow of time basically says that time can only go in one direction...forward. An example of this is that you scramble a egg not unscramble it.

[IM Egdall]

Search up the arrow of time. I had a hard time wrapping my mind over this concept too. But arrow of time basically says that time can only go in one direction...forward. An example of this is that you scramble a egg not unscramble it.

 

But physics has a surprisingly difficult time explaining why there is an arrow of time. The equations of physics work the same in the plus time and negative time direction. Brian Greene has a great discussion about this in The Fabric of the Cosmos . Apparently, the only way to define an arrow of time with the laws of physics is to apply "entropy" or the disorder in a system. For example, your egg is more disordered once it is scrambled -- so a forward arrow of time. But this is a statistical rule involving probabilities and only works for lots of constituents (e.g lots of atoms and molecules in the egg). So the arrow of time is still somewhat of a mystery.

 

See link: http://en.wikipedia.org/wiki/Arrow_of_time

[iAmSchrodinger'sCAT]

But physics has a surprisingly difficult time explaining why there is an arrow of time. The equations of physics work the same in the plus time and negative time direction. Brian Greene has a great discussion about this in The Fabric of the Cosmos . Apparently, the only way to define an arrow of time with the laws of physics is to apply "entropy" or the disorder in a system. For example, your egg is more disordered once it is scrambled -- so a forward arrow of time. But this is a statistical rule involving probabilities and only works for lots of constituents (e.g lots of atoms and molecules in the egg). So the arrow of time is still somewhat of a mystery.

 

See link: http://en.wikipedia....i/Arrow_of_time

Yes but isn't that the beauty physics. There is no way of knowing if you are right or wrong. Its just a big guessing game that involes numbers.

[J.C.MacSwell]

I registered only to post this question as it's bothering me since yesterday. So.. I was watching Discovery Science and saw in a show that scientists are trying to send info in the past. A guy was saying that when this will be possible, they will be able to send messages back in time and prevent many major events that happened in history.

 

Now this is where I don't understand it anymore. How come we didn't receive any message from the future? Our present and our past is the past of their future. Hope you understand what I mean. ( English not my natural language ) So how come all the major events still happened if "we" from the future didn't send any information back to the present ( past )? Or did they go "Oh let's not alter the history, it can be dangerous".

 

Also, if the scientists will ever discover time traveling or sending info back in time, shouldn't we receive their test messages or something? For me, it doesn't seem normal that they discover, let's say in 50 years, the time machine and don't use it to send people back in time for research. Of course I don't expect to see someone on TV saying that he is from the future, and if I would I'd say that most probably he has problems.

 

Sorry for repeating myself, as I said English is not my main language and I'm not a scientist. ( not even close to become one ) Anyway... what do you think?

 

Sorry about that. I was supposed to pass them on but got a little side tracked with the stock market.

 

J.C. April 1, 2015

[IM Egdall]

Yes but isn't that the beauty physics. There is no way of knowing if you are right or wrong. Its just a big guessing game that involes numbers.

 

 

Physics is so much more than a "guessing game". Just because there are certain aspects of reality we do not yet understand does not mean we understand nothing. There is a wealth of knowledge gained from quantum mechanics and general relativity. Detailed predictions of both theories have been verified by numerous experiments and observations over the past century. Quantum mechanics gives the theoretical basis for the great technology revolution of the 20th century. And general relativity is the basis for the first theory of the creation and evolution of the universe supported by scientific evidence - the Big Bang.

Edited April 14, 2011 by I ME

[owl]

My next agenda in this forum is to read this thread in depth. Admitting that I have only skimmed (and read the first few.)

Meanwhile, will someone please explain how we 'get out of' the present, either into the future or the past, since neither exist in the ongoing present! (Magic time machines don't count in science!)

 

Or is this just too simple a question for complex mental theories (and sci-fi mentality) about time to consider?

[owl]

Finished reading the entire thread. Anyone interested in discussing the ontology of time, i.e., "what is it, if an entity?," as a foundation for the next question, "Is it something through which one can travel?"

If so, please check out my (now dormant) thread in the Speculations section, The Ontology of time.

 

How about my simple question in above post?

Maybe the most fundamental focus is to define is, the ever present "now" as contrasted with was, the no longer present and will be, not yet present.

 

It is true, as already stated here, that an egg can not be unscrambled, or, to "travel further back in time," "unlayed." Likewise my future great grandchildren are not yet born, so there is no way to "visit them."

The whole concept of time travel is simply science fiction, from any reasonable perspective.

[IM Egdall]

Finished reading the entire thread. Anyone interested in discussing the ontology of time, i.e., "what is it, if an entity?," as a foundation for the next question, "Is it something through which one can travel?"

If so, please check out my (now dormant) thread in the Speculations section, The Ontology of time.

 

How about my simple question in above post?

Maybe the most fundamental focus is to define is, the ever present "now" as contrasted with was, the no longer present and will be, not yet present.

 

It is true, as already stated here, that an egg can not be unscrambled, or, to "travel further back in time," "unlayed." Likewise my future great grandchildren are not yet born, so there is no way to "visit them."

The whole concept of time travel is simply science fiction, from any reasonable perspective.

 

Try reading The Fabric of the Cosmos by Brian Greene. I think you may like it. He talks about the nature of time and physics. For one thing, he points out that per special relativity, time is not like a flowing river but more like a block of ice. It has to do with the fact that time is not the same for everyone - it is affected by relative motion. Events which happen "now" for you may have already happened or haven't happened yet for another observer in motion with respect to you. So in this sense all of spacetime exists (like a frozen block of ice). As Greene says, we think of all of space as really being out there- we should think of all of time as really being out there, really existing too. It is fascinating stuff, and gives a whole new view of what time is.

Edited April 15, 2011 by I ME

[Jasper]

But how does time dilation factor into this?

 

That's the limitation as we know it .. I thought (trying to understand this myself).. in that ... you can leave earth and in the reality of the "observer on earth" have centuries pass but to "the travelling person in space" away from earth it would be years only to them in their reality.

 

 

IE to the person in space time passes seemingly to them as it did on earth. The observer on earth's time scale shows time as slower relative to the traveller though. which is supposed to be why C is a constant apparently everywhere regardless.

 

 

Even though a smartypants in history said so.....well a rather famous one at that.

 

 

I am leaning towards there being parallel outcomes too but how many and why and how there would be a set limit on those to fit mathematically within a model is umm beyond me. Any suggestions?

 

I am interested in that direction as well booyah 2000 . I hope I am on the same page with your question. It was my intent.

Edited April 15, 2011 by Jasper

[owl]

I ME wrote:

It has to do with the fact that time is not the same for everyone - it is affected by relative motion. Events which happen "now" for you may have already happened or haven't happened yet for another observer in motion with respect to you.

 

You clearly have not given any thought to the "ontology of time" in general or as presented in my thread as referenced above. You assume "it" as an entity and that there is a different 'time environment' for every different frame of reference, effected by relative motion... ignoring the simple explanation that clocks simply "keep time" differently, (or "tick" at different rates) in different environments.

 

Have you ever studied "presentism?" There are different versions, but basically it posits that "it is always now, everywhere" regardless of relative motion among different frames of reference (or the light speed limit for conveying images and information.) Some posit a "global time structure", but if you read my comments in the ontology of time thread, you will see that, if time is not an entity, it can not have a "structure." It is just the duration of events between one (designated) "now" and another, as measured by anyone with a specific event focus and a stopwatch.

 

Jasper wrote:

But how does time dilation factor into this?

 

Ontologically, "What exactly dilates?" As I said above the simple explanation (for "time dilation") is that clocks simply "keep time" differently, (or "tick" at different rates) in different environments.

Time is not a 'thing' or medium through which one can travel. "It" is always now, wherever you are and however fast you are traveling. (And the "it" is the same usage as in "It is raining," i.e., not an agent or entity. Rain is just happening.)

Edited April 15, 2011 by owl

[MigL]

Oh, good greif, owl. I didn't realise there was an ontological interpretation of time as well as space. Just kidding.

Most physicists will agree with you. It is always now, everywhere. But will add, thogh not necessarily the same now.

 

Say you have a time machne and a notebook. Next week you will travel two weeks into the past, at which time you will write in the notebook "it worked!".

If you open the notebook now, are the words "it worked!" written in it or not ???

 

What I'm getting at, is could there be a law which we haven't formally expressed yet which forbids this ? Hawking has put foreward a law which forbids time travel ( I forget its proper mame ). It seems that if time travel were possible in the case presented above, causality would be violated, ie. something would happen which hasn't been caused yet. Could there be a law that forbids causality violation ??

 

HOWEVER!

 

Causality seems to be violated often in Quantum Mechanics. Take an electron beam passing through a single slit. It will give the classic single slit diffraction pattern. Now take the same beam and pass it through two slits and you get the classic two slit diffraction pattern. Now if you reduce the beam to a single electron and pass it through the two slits, obviously it can only pass through one of the slits, yet the same two slit diffraction pattern results. How does the electron know that another slit is open, unless it actually passes through both, then goes back and chooses the path of least action ?

[owl]

MigL:

Oh, good greif, owl. I didn't realise there was an ontological interpretation of time as well as space. Just kidding.

Most physicists will agree with you. It is always now, everywhere. But will add, thogh not necessarily the same now.

 

Presentism says that now is now everywhere, for the sun and earth and the whole cosmos... not about how much time it takes for light/information to travel between locations... so, no "different now" in different places. But of course info about "now" at the sun (present flares, for instance) will take 8+ minutes to reach us.

 

Presentism examines the ontology of time without the usual reification of time as an entity. Check out my "Ontology of time" thread in "Speculations."

 

Say you have a time machne and a notebook. Next week you will travel two weeks into the past, at which time you will write in the notebook "it worked!".

If you open the notebook now, are the words "it worked!" written in it or not ???

 

What I'm getting at, is could there be a law which we haven't formally expressed yet which forbids this ?

 

Why would it require a "formally expressed law" to know that an egg can not be unscrambled and then unlaid, or to know that we can not visit our unborn great grandchildren until they are, in fact, born (as previously expressed in this thread?)

I think science fiction has been adopted by a pseudo-science faction in this regard, to the detriment of science in general and reason itself in particular.

[MigL]

It is not a question of wether an egg can be unsrambled, That is an entropy question, and yes entropy can decrease locally. In effect there is a small possibility that the egg will unsramble. It is very small because of the statistical mature of macroscpic objects like eggs, but it can be large for non-statistical, sinle microscopic object. Atomic interactions will look perfectly normal wether the film runs foreward or backwards.

 

Causality violation is more subtle. You cannot scramble an egg without first breaking it, beating it, and cooking it, ie the breaking/beating/cooking are the causes that enable the scrambling effect to happen. Causality violation would permit the egg to scramble BEFORE breaking/beating/cooking. Just like in my previous example where the writing appears in the book BEFORE having gone into the past to write it.

[DrRocket]

MigL:

 

 

Presentism says that now is now everywhere, for the sun and earth and the whole cosmos... not about how much time it takes for light/information to travel between locations... so, no "different now" in different places. But of course info about "now" at the sun (present flares, for instance) will take 8+ minutes to reach us.

 

This is a flat contradiction of general relativity unless spacetime were flat, in which case special relativity would apply. In the presence of curvature, hence in any universe that includes matter (most people would agree that our universe qualifies in this regard), time, like space, is local. There is no clear meaning to a comparison of "time here" with "time there". What one can meaningfully compare is the time recorded on two clocks between spacetime intersections of their world lines -- this is the essence of the "twin paradox".

 

That time is, modulo division by c, just the length of the world line of the clock in the Lorentzian metric of spacetime, known as "proper time".

 

You continue to assert expertise in the ontology of spacetime while simultaneously making outrageous and false statements regarding the content of general relativity. How can you make such positive assertions regarding the reality of constructs of general relativity when you have no idea what the theory actually says ?

[owl]

Time travel means we can go back to the past or go forward into the future or both.

If this were possible we could visit the past before we scrambled the egg, or further back, before it was laid; and if we could visit the future we could visit as yet unborn progeny. Make of it what you will, but time travel is not possible, however interesting it is as a device for science fiction.

 

DrRocket, as always you use "spacetime" as a given matter of established fact. I'm guessing you didn't read any of the material I suggested on the ontology of it. Fine, but that doesn't make its critics wrong just because you refuse to even engage in the conversation on the subject.