Time Machine

[Drake Tungsten]

it's likely they wouldn't get named that name then, would they?

Say that the letter wasn't to be opened until 2002 or something like that, and then they find out who the name was. It could work.

Skanky has the right idea, sort of. I would make sure that I told the Pope that it was for his eyes only and the eyes of later Popes (kinda like the Fatima prophecies). In the letter, I'd also stress that this information can't get out, or the Antichrist will change his tactics in order to successfully destroy the world.

At any rate, I doubt my neighbor or whoever else I decide needs to die will have any sort of knowledge of ancient Vatican prophecies. Ignorance works in my favor...

[FrostyBoy]

If you go back an cancel seinfeld, I would have to go back and kill you before you do that.

[Adalbertus]

We are assuming that a time is possible. What you are

doing is assuming it isn't possible. Do you think the Universe or the laws of physics cares about human history? Going back in time would displace atoms. Just taking a step would move soil. That is changing the past right there.

The only way time travel would be possible is if the multiple universe concept is real.

Not quite. There are spacetime geometries which would allow time travel (I've heard a seminar talk on that), and (most) quantum theories of gravity even would make it highly improbable that such structured do not exist on microscopic scales. (for a simple model, imagine the time axis wrapped as a cylinder - which to all our knowledge is not the case in reality).
The thing is time travel wouldn't change anything in the past because it is already built-in into what we know as past. There is no contradiction in you appearing during the 30 year's war. We even might have heard of you. But you cannot be someone we have a birth certificate from 1600 (or it is a fake). You cannot change the history as it was.

[Ethelred]

The thing is time travel wouldn't change anything in the past because it is already built-in into what we know as past. There is no contradiction in you appearing during the 30 year's war. We even might have heard of you. But you cannot be someone we have a birth certificate from 1600 (or it is a fake). You cannot change the history as it was.

You are still doing the same thing. There may not be a contradiction of my appearing in the 30 Years War BUT simply by being there things MUST change. I may not be able to be someone that we have Birth Certificate of (don't bet on that either as bribes are not exactly limited to the present) I can be standing in the way of the father of the person for a fraction of a second at the right moment and thus the Birth Certificate may have the same name it will be a different sperm that fertilized the egg.

Now if you can come up with a mechanism for a Cosmic Censor that would be different. Everyone I can think of entails stopping time travel at least before the making of the time machine. Whats to stop me from burning the Certificate. Magic? Not getting to the past will work but that isn't compatible with an assumption of a time machine.

As I said you are doing the same thing still. There would be a NEW universe one thats splits of from our present one. Eventually different people and a different track of history. THIS Universe would be unchanged. You are still thinking of a single path of time and not a multiple universe, which has the advantage of satisfying at least some of the needs of quantum mechanics.

Here is a rather intriguing article on the Multiverse concept:

http://www.newscientist.com/hottopic...sp?id=22994400

Yes I know the the present ideas on time travel have some major problems with the physics. I did point out we are assuming that we HAVE a functioning time machine. I don't think anyone is hypothesizeing traipsing out to the nearest rotating black hole. That would be macroscopic but the transportee would be shredded by tides. A rotating black hole at the center of a galaxy would have less of a gradient and therefor the tidal forces would be smaller but I think they would still be pretty impressive, don't have a clue about how much lower for say 60,000 solar masses vs. Cygnus X-1.

[TheStinger]

I'd go and stomp on whatever creature evolved into a spider

[ZoboZeWarrior]

My idea is that you cannot change the past. Because the fact that you return in past time is already an existing past event.

I mean some "strange" event we could experimentor we have experimented are the fact of "men from futur".

So you cannot go back in the past and kill Hilter before he became the fuhrer. I mean, you could try it, but your action will failed because in our past Hitler became the Reich Fuhrer.

[Adalbertus]

Whats to stop me from burning the Certificate. Magic? Not getting to the past will work but that isn't compatible with an assumption of a time machine.

You wouldn't do it. And it's not magic but causality which prevents you from doing so.
The thing is that all models of the universe we have are governed by differential equations, which are solved globally from initial or boundary conditions. Our "Galileian" concept of spame and tice is completely useless when we deal with this kind of geometries. (And I tend to the idea that our freedom - if it is not illusion, but even to assume it is an illusion would appear as an act of free will - lies not in making our decisions "right now" ("right now" is an illusion created by our way we perceive spacetime) but to control a small part of boundary conditions in the universe. I'm not sure if this view is really superior to the traditional view, but I've more and more the impression it is not worse .

[TheStinger]

Originally posted by Adalbertus

You wouldn't do it. And it's not magic but causality which prevents you from doing so.
The thing is that all models of the universe we have are governed by differential equations, which are solved globally from initial or boundary conditions. Our "Galileian" concept of spame and tice is completely useless when we deal with this kind of geometries. (And I tend to the idea that our freedom - if it is not illusion, but even to assume it is an illusion would appear as an act of free will - lies not in making our decisions "right now" ("right now" is an illusion created by our way we perceive spacetime) but to control a small part of boundary conditions in the universe. I'm not sure if this view is really superior to the traditional view, but I've more and more the impression it is not worse .

Well that was so obvious i didn't think it needed saying

[Drake Tungsten]

Why'd you guys have to kill off an interesting thread with your damn science? Can't you let us non-geeks have some fun once in a while?

[Ethelred]

Originally posted by Adalbertus

You wouldn't do it. And it's not magic but causality which prevents you from doing so.

What is the process? Casaulity will put out the fire by magic?

The thing is that all models of the universe we have are governed by differential equations, which are solved globally from initial or boundary conditions.

New boundry.

Our "Galileian" concept of spame and tice is completely useless when we deal with this kind of geometries. (And I tend to the idea that our freedom - if it is not illusion, but even to assume it is an illusion would appear as an act of free will - lies not in making our decisions "right now" ("right now" is an illusion created by our way we perceive spacetime) but to control a small part of boundary conditions in the universe.

And someone with a time machine has much more control of those boundries.

General Relativity was created partly to avoid boundry conditions.

I'm not sure if this view is really superior to the traditional view, but I've more and more the impression it is not worse .

Its still magic in this case.

IF I can go back in time

THEN I may stand right next to the certificate

AND if I can make a spark

THEN I can light the certificate.

SPARKS are physicaly possible.


So whats stopping the spark? Magic?

Its not causality. Thats just saying magic in this case. After all the cause is in another universe. The one I came from to get to the one that I created simply by appearing where I never was before.

[Drake Tungsten]

I see my cries have gone unnoticed...

[Ethelred]

Don't whine. Time travelers must be made of sterner stuff. You have to be able to withstand all that waiting in line at the Temporal Customs Office.

[Odin]

Originally posted by TheStinger
I'd go and stomp on whatever creature evolved into a spider

[Ethelred]

Absolutly

He should stomp on the proto-MOSQUITO.

Spiders keep those vile things down.

[DinoDoc]

Whats to stop me from burning the Certificate. Magic? Not getting to the past will work but that isn't compatible with an assumption of a time machine.

If you burned the certificate, why would you go back into the past to burn the certificate?

[Ethelred]

Originally posted by DinoDoc

Quote:

Whats to stop me from burning the Certificate. Magic? Not getting to the past will work but that isn't compatible with an assumption of a time machine.

If you burned the certificate, why would you go back into the past to burn the certificate?

Because YOU remember the certificate.

There seems to be difficulty here for some of POINT OF VIEW. The whole idea of time travel REQUIRES a muliverse of branching time.

You decide some certificate must be burned.

You happen to have a Handy Dandy Acme Time Machine.

You go go back in the past.

You burn the certificate.

You go forward

You see a world in which the certificate burned. IT IS NOT THE WORLD YOU STARTED IN. You most likely weren't even born in the BRANCHED world.

The world you came from STILL EXISTS. Its just on a different track. You didn't change a thing in the world you came from. You created a whole new branch of time.

Where once there was one branch now there are two. Two of many.

[Capt Dizle]

I dunno. Deep stuff. I just wanna know why my branch has so many damn liberals sitting on it.

[Lung]

Originally posted by Ethelred


I am fairly certain that if time travel is possible then you create a new universe and there are no paradoxes in that case. How could you enter the past all otherwise as simply being there will eventually change the future in some way. Besides I was in Junior High School then. There would be two of me. One 12 years old and the other whatever it would be when I was to go back.

Safe in the knowledge that you have created a parallel universe simply by going back in time, i would visit some early humans and become a god I could teach them modern magic without fear of repercussions to my own existence

[Odin]

Originally posted by Ethelred
Absolutly

He should stomp on the proto-MOSQUITO.

Spiders keep those vile things down.

you are forgeting one thing, mosquitos are pollinators, DAM*

[carnide_]

I dont think it will be practical to build a time machine.
Check here:
http://apolyton.net/forums/showthrea...threadid=62117

[Aeson]

Can causality and time travel (in a traditional sense, "time machine" type stuff) coexist? In a causal existance, building the time machine and using it to "go back" in time would actually just be continuing on the same time path. Moving into the future as it were, but making tremendous changes to the environment during the "time travel" transition.

Consider an object at a certain position. After it has been moved, moving it back doesn't constituted going back in time. This is apparent because all the other objects which are now in new positions/states that don't coincide with the past moment (this includes the mental state of any third party observers as well). But moving everything back (including the mental states of any third party observers) would seem like going back in time, even though it is just following the natural progression of time.

Looked at in a causal light, you can recreate a moment in time, but never actually go back in time. If you are recreating a moment where there was a certificate to burn, it is no more changing the past to do so than it would be to burn a like certificate in the future.

--------------

As for paradoxes, your existance in a time frame that you hadn't previously existed in would cause differences in the future regardless of what you did. Just the air you displace and the microbes you pick up or leave behind could very well significantly alter the progression of history. Think of the chaos theory example of an unaccounted for butterfly in a weather prediction system.

[JCG]

I'd go back and kill Marx and/or Engels, and their contemporary brethen...

Or on the other hand, I could go back and topple all the Kings and Lords that were around back then...

Same thing.

[johncmcleod]

originally posted by Aeson:
Can causality and time travel (in a traditional sense, "time machine" type stuff) coexist? In a causal existance, building the time machine and using it to "go back" in time would actually just be continuing on the same time path. Moving into the future as it were, but making tremendous changes to the environment during the "time travel" transition.

Consider an object at a certain position. After it has been moved, moving it back doesn't constituted going back in time. This is apparent because all the other objects which are now in new positions/states that don't coincide with the past moment (this includes the mental state of any third party observers as well). But moving everything back (including the mental states of any third party observers) would seem like going back in time, even though it is just following the natural progression of time.

Looked at in a causal light, you can recreate a moment in time, but never actually go back in time. If you are recreating a moment where there was a certificate to burn, it is no more changing the past to do so than it would be to burn a like certificate in the future.

--------------

As for paradoxes, your existance in a time frame that you hadn't previously existed in would cause differences in the future regardless of what you did. Just the air you displace and the microbes you pick up or leave behind could very well significantly alter the progression of history. Think of the chaos theory example of an unaccounted for butterfly in a weather prediction system.

Wow. That's what I call high level thinking. Though I don't understand that too well, I agree with you on everything. The slightest action could completely change everything. The displacement of molecules could cause different sperm (though Ethelred was the one that said that) to meet the egg, for it might have caused a the whole thing to happen a split second later. Who knows. It could completely alter evolution, for a different mutation might come out for one creature, and maybe Hitler may have never been born.

[Odin]

Originally posted by Aeson
Can causality and time travel (in a traditional sense, "time machine" type stuff) coexist? In a causal existance, building the time machine and using it to "go back" in time would actually just be continuing on the same time path. Moving into the future as it were, but making tremendous changes to the environment during the "time travel" transition.

Consider an object at a certain position. After it has been moved, moving it back doesn't constituted going back in time. This is apparent because all the other objects which are now in new positions/states that don't coincide with the past moment (this includes the mental state of any third party observers as well). But moving everything back (including the mental states of any third party observers) would seem like going back in time, even though it is just following the natural progression of time.

Looked at in a causal light, you can recreate a moment in time, but never actually go back in time. If you are recreating a moment where there was a certificate to burn, it is no more changing the past to do so than it would be to burn a like certificate in the future.

--------------

As for paradoxes, your existance in a time frame that you hadn't previously existed in would cause differences in the future regardless of what you did. Just the air you displace and the microbes you pick up or leave behind could very well significantly alter the progression of history. Think of the chaos theory example of an unaccounted for butterfly in a weather prediction system.

Huh?

[johncmcleod]

What he is basically saying is make everything go backwards, to recreate a moment in time. I don't know when that'll be possible though. How can we change the path of the sun?