129 replies to this topic

[psyche101]

Verloc, on 29 January 2013 - 11:10 AM, said:

@OnereaderOne: Timetravel, in the way you are referring to or as in "Back to the future" would not be possible.

The universe is expanding agree? so if you are at the edge of the expansion you are in the future in relative position to the earth, if you were then to travel at the speed of light towards the center of the universe you would, in essence, be travelling back in time and vica versa. But keep in mind, that while you are travelling stars are born and destroyd, civilizations rise and fall with the rotation of their planets, comets/asteroids hit planets and extinguish life, sun's go supernova etc. and all these things are happening eveywhere in the universe simultaneously.

Since the expansion started all these things have been happening, so to say that you can, for instance, go back to the beginning of our planet's creation and change something, whatever that may be, is impossible as it has already happened.The earth is no longer in the position, relative to the universe expansion bubble, it was when it emerged as a planet.

There may be cycles of civilizations on a planet that repeat themselves, but everything that has happened, has happened, theres no way to literally go back in time and change anything.The earth ofcourse does not travel at the speed of light, so it will always stay in its relative position in the galaxy/universe untill influenced by cosmic events.

This is my opinion mind you, care to refute it?

The rolling film paradox Nice to see someone discuss it, and understand it!

However, that does not prevent travel as far as I can see, it simply does not change history. If I am reading it wrong, could I ask you to extrapolate please.

Here is some food for thought. What if one "time travels" to a point in the past where space does not exist yet. I wonder what we would encounter. Not before the big bang mind you, but say maybe 10 billions kilometers in fornt of the expansion border. I wonder what we might find?

[Colonel Rhuairidh]

I am very pleased to see the notion of Time travel being considered seriously and not just denied out of hand, as usually happens with any kind of 'out of the box' thinking, although I still can't help thinking that a spacecraft from (perhaps) another planet in the solar System might not be a more straightforward suggestion, on the much-abused principle of the Razor of the good William of Ockham, since we know that space travel (at sublight speeds, at any rate) is in fact possible, and that spacecraft can in fact exist, since we've made some ourselves ....
Anyway, on the subject of Time travel, I think the idea that what was in the past has already happened, and so that can't be altered, but that you could go back an watch it, seems entirely reasonable. That might mean that someone could go back to any given place and any given point in time, but they wouldn't be able to change history (e.g. they wouldn't be able to assassinate some major figure in history), since, if they went back to that point in Time, then they were already there at that time. It wouldn't be as if they weren't there before, they were all along.  Anyway, it's an interesting subject for discussion, isn't it, even if it need not replace ET ...

[Frank Merton]

psyche101, on 30 January 2013 - 06:22 AM, said:

Not before the big bang mind you, but say maybe 10 billions kilometers in fornt of the expansion border. I wonder what we might find?

Um, there is no "expansion border."  Either the universe we live in is infinite or it curves in on itself (perhaps in a fifth dimension, but it has been shown that this is not necessary -- that the four we have could curve in).

[psyche101]

Lord Vetinari, on 30 January 2013 - 07:51 AM, said:

I am very pleased to see the notion of Time travel being considered seriously and not just denied out of hand, as usually happens with any kind of 'out of the box' thinking, although I still can't help thinking that a spacecraft from (perhaps) another planet in the solar System might not be a more straightforward suggestion, on the much-abused principle of the Razor of the good William of Ockham, since we know that space travel (at sublight speeds, at any rate) is in fact possible, and that spacecraft can in fact exist, since we've made some ourselves ....

Out of the box thinking is never denied, nonsense is. I am not sure why, but some people, not you specifically, but many people seem to think if they come up with a whacky alternative to a mainstream ideal, this is "out of the box thinking" and pople are "open minded" if they accept it.

When what is really happening is that someone made some crap up, another ignorant person who cannot understand science goes "Ohh yeah, that sounds good" and then the two collude to believe they have some major breakthrough in science, and the academic world is ignoring them, when all they have is a pile of tosh. Before you know it, half a dozen ignoramuses get together, someone makes a website, and then more ignoramuses think this tosh it fact.
Thusly, we have AA and the media version of the ETH.

If someone has an out of the box ideal, all they need to id explain themselves in detail. If the claims is valid, it will stand up to any set of questions. Fact will not be denied, and most certainly not by a skeptic. Physics and analysis will prove if something is workable, if it is, then one will be heralded with accolades  but if it is a pile of tosh, then people will laugh at you. That is just the real world, and not really anything to do with out of the box ideas at all.

One has to know the box to get out of it I reckon. Some people just leap out and stick their heads in the clouds.

Yes, spacecraft can exist, yet spacecraft too has to be realistic to be workable. Making stuff up on the spot solves nothing, but I imagine gives some a warm fuzzy feeling. A few simple and basic question often indicate of we are dealing with out of the box thinking, like the Lost Shaman Roswell Hypothesis, or just full of crap, like the stupid garbage about stacking rocks in the AA thread. One is genuine, one is painfully stupid.

Lord Vetinari, on 30 January 2013 - 07:51 AM, said:

Anyway, on the subject of Time travel, I think the idea that what was in the past has already happened, and so that can't be altered, but that you could go back an watch it, seems entirely reasonable. That might mean that someone could go back to any given place and any given point in time, but they wouldn't be able to change history (e.g. they wouldn't be able to assassinate some major figure in history), since, if they went back to that point in Time, then they were already there at that time. It wouldn't be as if they weren't there before, they were all along.  Anyway, it's an interesting subject for discussion, isn't it, even if it need not replace ET ...

That be the rolling film paradox. Just like a movie film, each day could be considered (or hour, minute or second for that matter) as one frame of this film. You can go back and shoot who you want, but the film is already shot so to speak. so the next day, everything is as it happened already. I groundhog day type scenario, but we do not know if that applies or the Grandfather paradox, whereby if you go back and shoot someone, you change history.
Of course the Novikov self-consistency principle says that the time traveler was always in he past, and the future, so nothing has changed no matter what.
And that is merely scratching the surface, variants of the above, and many other exist to.
It is an interesting discussion, but I feel ET best replace it before the thread is closed for being off topic.

[Frank Merton]

I'm inclined to the view that time is not really a dimension (I know general relativity treats it as one, but the theory works mathematically without this -- treating it as a dimension just helps with mental picturing).

My view is that there is no travel in time, even in the ordinary sense.  What there is is the present, but it constantly changes.  The "past" is not a place, but just the traces of the way the present was, and the future is similarly not a place, but what the present becomes.

[psyche101]

Frank Merton, on 30 January 2013 - 08:12 AM, said:

Um, there is no "expansion border."  Either the universe we live in is infinite or it curves in on itself (perhaps in a fifth dimension, but it has been shown that this is not necessary -- that the four we have could curve in).

Yes, of course you are right, the Universe can be finite, but have no edge, I worded that badly, I mean being able to observe that from a distant point, such as God is suggested to do perhaps, or something like a Multiverse. Any observational outside point, hence my wonderment.

[psyche101]

Frank Merton, on 30 January 2013 - 08:30 AM, said:

I'm inclined to the view that time is not really a dimension (I know general relativity treats it as one, but the theory works mathematically without this -- treating it as a dimension just helps with mental picturing).

My view is that there is no travel in time, even in the ordinary sense.  What there is is the present, but it constantly changes.  The "past" is not a place, but just the traces of the way the present was, and the future is similarly not a place, but what the present becomes.

Would you not consider time dilation a form of time travel?

[Frank Merton]

psyche101, on 30 January 2013 - 08:37 AM, said:

Would you not consider time dilation a form of time travel?

I think you are referring to the observation that clocks slow down when they are accelerated relative to other things.

This is a counterintuitive but well-demonstrated consequence of relativity.  All it implies is that if you are accelerated the changes that the universe experiences slow down compared to elsewhere.  As a result you return from your long trip younger than your twin who stays behind.

This works fine whether or not you consider time a dimension, as it has to do with rate of change in different reference frames.

[The Exodia]

sigh.

[Colonel Rhuairidh]

The Exodia, on 30 January 2013 - 11:59 AM, said:

sigh.

Come again, over?

[SwampgasBalloonBoy]

psyche101, on 30 January 2013 - 06:22 AM, said:

The rolling film paradox Nice to see someone discuss it, and understand it!

However, that does not prevent travel as far as I can see, it simply does not change history. If I am reading it wrong, could I ask you to extrapolate please.

The rolling film paradox is nothing but a science fiction speculation, yes? There are no scientific proof. I thoughts you believe in scientific facts, not fiction, Psyche.

From what I can understand, the time traveler cannot change anything no matter what actions he take. Events have already been set, there can be only one outcome no matter what he does. Let say a person goes back in time, met a women, fall in love and get married. Would the marriage have happened, will they be able to have kids? In another scenario. If the time traveler got into a gun fight, and he loses, would he died right there? If he won, would the other person died? If non of these events changes anything, would its still be considered reality? Or is it a fantasy? Can he throw away all morality because no matter what he does, it wouldn't make any difference because all these people life wouldn't be affected by it? In another example of Groundhog Day you gave in another post. If a person chose to relive the happiest day of his life over and over again, obviously it's just one day to the people around him, but he would still carry the memory over to the next groundhog day. He continued to accumulate the memory of each repeating days, but does he get old physically? If he doesn't is he an immortal? if he does, would the people around him will notice that he's much older than they are?

If it is a fantasy because he can't changed anything, then isn't this akin to the holodeck of in Star Trek? The holodeck can be program to create real life event to the detail and allow the user to immerse into the game. They can make different decisions in the game but once they step out of the holodeck, they're back to reality. In this case, the universe timeline can be considered an infinite program, or time frames of the past, present and future that will allow the time traveler to access to and immerse himself in it. But no matter what this time traveler does, the course had been set, he can't change it.

If we are to prescribe to this rolling film paradox, does we have to accept that everything in the universe is predetermined? All events and outcome have been set, no time travelers can affect it? Isn't this sound familiar? There's quite a few religious fanatics that believe everything is predetermined. Everything in their life happened for a reason, it is a "test" from above. Isn't this attribute to some unknown higher power? I know how much you hate it, Psyche.

psyche101, on 30 January 2013 - 06:22 AM, said:

Here is some food for thought. What if one "time travels" to a point in the past where space does not exist yet. I wonder what we would encounter. Not before the big bang mind you, but say maybe 10 billions kilometers in fornt of the expansion border. I wonder what we might find?

If space doesn't exist, then how can ones be in space?

[Sir Wearer of Hats]

I've come to think of Time Travel as being like rail travel.
Basically, you can't travel where there aren't tracks on a train, and so with time travel you can't travel to a place where there was no time travel (so you can go back to the day the first time machine was turned on, but not a second before).

[SwampgasBalloonBoy]

Wearer of Hats, on 30 January 2013 - 11:09 PM, said:

I've come to think of Time Travel as being like rail travel.
Basically, you can't travel where there aren't tracks on a train, and so with time travel you can't travel to a place where there was no time travel (so you can go back to the day the first time machine was turned on, but not a second before).

Kind of like a telephone isn't it? you can call someone if they don't have a phone.

[psyche101]

Frank Merton, on 30 January 2013 - 08:53 AM, said:

I think you are referring to the observation that clocks slow down when they are accelerated relative to other things.

This is a counterintuitive but well-demonstrated consequence of relativity.  All it implies is that if you are accelerated the changes that the universe experiences slow down compared to elsewhere.  As a result you return from your long trip younger than your twin who stays behind.

This works fine whether or not you consider time a dimension, as it has to do with rate of change in different reference frames.

Time dilation is an actual difference of elapsed time between two events as measured by observers either moving relative to each other or differently situated from gravitational masses. I am sure we agree on that much. However, I think this conversation might be more suited to the astronomy section? It is an interesting subject with many aspects to be discussed for sure.

[psyche101]

SwampgasBalloonBoy, on 30 January 2013 - 11:05 PM, said:

The rolling film paradox is nothing but a science fiction speculation, yes? There are no scientific proof. I thoughts you believe in scientific facts, not fiction, Psyche.

From what I can understand, the time traveler cannot change anything no matter what actions he take. Events have already been set, there can be only one outcome no matter what he does. Let say a person goes back in time, met a women, fall in love and get married. Would the marriage have happened, will they be able to have kids? In another scenario. If the time traveler got into a gun fight, and he loses, would he died right there? If he won, would the other person died? If non of these events changes anything, would its still be considered reality? Or is it a fantasy? Can he throw away all morality because no matter what he does, it wouldn't make any difference because all these people life wouldn't be affected by it? In another example of Groundhog Day you gave in another post. If a person chose to relive the happiest day of his life over and over again, obviously it's just one day to the people around him, but he would still carry the memory over to the next groundhog day. He continued to accumulate the memory of each repeating days, but does he get old physically? If he doesn't is he an immortal? if he does, would the people around him will notice that he's much older than they are?

If it is a fantasy because he can't changed anything, then isn't this akin to the holodeck of in Star Trek? The holodeck can be program to create real life event to the detail and allow the user to immerse into the game. They can make different decisions in the game but once they step out of the holodeck, they're back to reality. In this case, the universe timeline can be considered an infinite program, or time frames of the past, present and future that will allow the time traveler to access to and immerse himself in it. But no matter what this time traveler does, the course had been set, he can't change it.

If we are to prescribe to this rolling film paradox, does we have to accept that everything in the universe is predetermined? All events and outcome have been set, no time travelers can affect it? Isn't this sound familiar? There's quite a few religious fanatics that believe everything is predetermined. Everything in their life happened for a reason, it is a "test" from above. Isn't this attribute to some unknown higher power? I know how much you hate it, Psyche.

Well I do hope our recent conversations have inspired you to learn some more about the concept of time travel It is not everyone's bag, and lets face it, hardly the thing one wakes up and thinks "I am going to read about time travel today" so most people are likely to be a bit fuzzy on detail's, hell I do not claim to be an expert myself, but like to think I have a basic understanding.

But again, I am not sure if I read you right, but are you saying someone is perdisposed to the above paradox? I did mention many exist, which one is correct be the biggest question here I think? Do any? Do the dimensions in string theory allow for dimensions that allow parallel alternatives to exist? Was thew Grandfather paradox right all along? All I have stated is that waving to someone, even yourself, in different time frames as far as I know creates no paradox.

SwampgasBalloonBoy, on 30 January 2013 - 11:05 PM, said:

If space doesn't exist, then how can ones be in space?

Now your catching on!!!!!!!!

Edited by psyche101, 31 January 2013 - 01:03 AM.