Time travel and phantom information....

[Scott]

I was thinking the other night, as I usually do, and I was thinking about the possible reasons fo impossibility of time travel, aside from the usual blah blah about the space-time continuim and such. I came up with a couple realativly simple situations to that would cause some kind of strange effect in the universe if time travel were possible.

 

I call this one the Noah's Arch effect. Suppose you were living today, and in the bible you read about the story of Noah's Arch. Then you decide to go back in time to Noah's time. When you get there, you find that he does not know of the flood coming. You decide to tell him its comming, and he builds his arch and the story is written in the bible. But then the only reason that the story was in the bible was because you told him and the only reason he built the arch was because you told him the story that is now in the bible. If you analyze this, you will find that the story would have come from no-where. I dont think information and stories can pop up out of thin air, so I call it phantom information.

 

Another problem to that would block your way to go back in time is that a second before you're going back in time, your not going back in time, so you would keep flipping the switch on the machine over and over and over again.

 

Leave some comments...

 

Cheers!

[Sayonara]

It doesn't come from nowhere - it's called predestination.

 

All you've done is shift the original event on your original time travel. The information could have literally come from anywhere between Noah deciding to build an ark, and you leaving the present to go to the past. It's only after that journey starts that the point of origin is obfuscated to an outside observer.

[Newtonian]

Its better to just accept that our past (pre 2005) is unobtainable.If ever a device such as a time machine were possible,one could only travel back to its construction and first use.

 

You could not use a time machine to go back in time and destroy the invention of the time machine.

[Sayonara]

Its better to just accept that our past (pre 2005) is unobtainable.If ever a device such as a time machine were possible,one could only travel back to its construction and first use.

Better, or faster?

 

You could not use a time machine to go back in time and destroy the invention of the time machine.

You sound fairly certain of that.

[Stumblebum]

Time travel conjures up many paradoxes. What if there was a mass produced time machine available and millions of homes were outfitted with the device? Let's say everyone wanted to witness the birth of Christ....... possible? Don't recall the part about millions of people being there. One of three things, can't be done, or it was done and nobody bothered to note it, or it never happened.

 

Of course some have gotten around the paradox problems by creating parallel or multi universes, sort of like tv's 'Sliders'. Each event causing an infinite amount of effects, thus a number of realities exist alongside each other. I always wondered why one could supposedly go back in time in another universe and not in their universe of origin. Whether you can go back in time or not, that is the question, the destination is irrelevant.

[Sayonara]

Time travel conjures up many paradoxes.

Not really. It tends to conjure up nothing more than inflexible logic. The only half-decent paradox in time travel is the grandfather paradox, and that's not even a real paradox.

[syntax252]

It is impossible for me to accept the idea of time travel without thinking in terms of plural realities.

 

The reality that we call "here and now" are the sum total of all past events since the big bang, and maybe even before.

 

Therefore, if one were able to travel backwards in time, reality as we know it, would not be the same as it "was," which would be somewhat confusing to the general population.

 

I postulate that if one were to travel backwards in time, he would be creating another "here and now" that would exist in another dimension that we would be completely be unaware of.

 

If it is at all possible, then it has already happened. If it is not possible, we will never know.

[Sayonara]

Assuming of course that the previous past can't be both the same and different

[Stumblebum]

Paradoxically speaking of course.

[ecoli]

Assuming Noah's arc and the flood actually happened... You would have to tell Noah to build the arc for Noah to get on the arc and survive the flood...resulting in the propogation of today's population and eventually you. You build a time machine and travel back in time to tell noah about the flood...

 

You see the cycle? One thing is dependent on the other.

[Stumblebum]

God is a time traveller. I like that. Only God or a time traveller would know what the future holds. Nothing like predicting the future with accuracy to win over a crowd.

[ecoli]

Now your thinking like a mystic

[Stumblebum]

Would we know if a tt altered our history? Maybe before he went back, you or I never were.

[syntax252]

Assuming of course that the previous past can't be both the same and different

 

Actually it could be any number of things. It just depends on how many times it was visited.

 

I really don't think that such a thing as time travel is possible.

[syntax252]

Would we know if a tt altered our history? Maybe before he went back, you or I never were.

 

That is where the alternate realities come in. In one reality, you exist, in another, you don't.

 

To me, if one cannot embrace plural realities, time travel is not possible.

[Sayonara]

Paradoxically speaking of course.

That is expressly not what I intended to say.

[War Is Greed]

Scott,

 

Read the story of Gilgamesh. That should clear up your ideas of Noah's flood.

 

In regards to time travel, how is it physically possible to visit an event that has already happened. I have virtually no physics background but I have read "The Tao of Physics" and Capra explains that everything happens in frame like order (imagine a slide show.) I am having a tough time expressing this idea but how could you visit a "frame" that has already passed?

[grey arms]

There are countless objections to the logical possibility of backward time travel, but rarely do i find discussions pertaining to the displacement of matter that backward time travel would inevitably cause.

 

Let me give an example of what i mean. Say you have invented a time machine prototype that's about the size of an apple. You are able to adjust a dial on it so that it can appear at any time in the past or future that you desire. Now lets imagine you put the device on a table in the kitchen at 8pm friday and set it to travel back in time exactly one day. It arrives at the same place on the table at 8pm thursday.

 

Now things get tricky when we try and imagine HOW it gets there. In my experience there are two common assumptions made about the path of the machine. It either (a) vanishes from its position and enters some form of "time-warp" dimension only to reappear at the set time, or (b) remains in its position and witnesses time unfold backwards all around it (like in H.G Wells' novel).

 

In (a) we can plainly see a violation of the basic laws of the conservation of energy. At 8pm thursday at point P on the table we find a physical object that did not exist one moment prior, meaning that the total mass of the universe has increased immediately by the mass of the time-machine. Similarly, the total mass of the universe a moment after 8pm friday decreases by the mass of the device.

 

If we adopt the many-worlds hypothesis for such a situation, and say that a new universe is created at 8pm thursday, a universe with slightly greater mass, then we would have to say the same for 8pm friday, where a universe is created with slightly smaller mass. What, then, happens to the original universe (assuming it cannot increase or decrease in mass)?

 

(b) seems slightly more consistent. But the problems are obvious. So the time machine is set and turned on. What happens? If it obeys the laws of conservation of energy, it must remain at P even after it is set. In fact, it would be difficult to determine whether anything at all has happened. From the perspective of someone inside a machine though, the world is witnessed in backwards motion. Or is it? If the machine must remain at P even after it is set, so too must the person inside. We can asume that neither the device nor the person inside is experiencing a backward flow of time AFTER 8pm friday, so they would in fact experience forward flow as normal. So then, what EXACTLY is experienced at P at exactly 8pm? Does the person experience the backward movement of time before 8pm and the forward movement of time after 8pm simultaneously?

 

My final objection can be seen in both scenarios. What happens if, at 8pm thursday, at point P on the kitchen table, someone has left another object? Would the time machine displace the matter of the coffee cup you left there accidentally? Can two things exist in the same point in space and time?

[Sayonara]

Actually (and this just came up in another thread) there's no reason why energy conservation cannot be preserved under either scenario.