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Brandon Pilcher
2005-Oct-16, 08:04 AM
I want to be able to see dinosaurs, but from what I've heard, time travel is only possible if you're heading towards the future.

Candy
2005-Oct-16, 08:20 AM
From what I've read on the BABB/BAUT about time travel, you are right, you won't see the dinosaurs. You will see me yesterday, though. I wish I could tackle this with more expertise, but I will wait for the experts to arrive. :)

adiffer
2005-Oct-16, 08:45 AM
There are games one can play with unusual black holes. The math folks say it might be theoretically possible. Of course, if you look at those games, there is no way a human could survive the trip. Your individual particles might arrive in the past, but the sense of order they have right now that defines YOU sure wouldn't.

Ken G
2005-Oct-16, 10:29 AM
Probably one should distinguish between "seeing" the past, and "being in" the past. You can see dinosaurs if you can get the light they emitted to bounce off something 100 million light years away and come back (in principle!). But can you actually take an action that affects the past? My speculations on that are no better than anyone else's, but one must distinguish between whether it is possible in principle, versus whether it is practical, and I agree with adiffer that there does not appear to be any reason to think it's practical (plus if it were practical, we'd most likely have ample historical evidence of it by now! Not to mention the logical paradoxes.) You'd be better off shooting for the Jurassic Park scenario if you want to actually walk amongst dinosaurs (and look what happened to those people!)

Eroica
2005-Oct-16, 10:43 AM
I'd have to say no, because the past no longer exists.

Well, actually the past does exist, but it's now the present. In other words, the past did once exist as the past, but it no longer does; it now exists as the present, and one day it will exist as the future. I hope that's clear.

Brandon Pilcher
2005-Oct-16, 11:37 AM
Probably one should distinguish between "seeing" the past, and "being in" the past. You can see dinosaurs if you can get the light they emitted to bounce off something 100 million light years away and come back (in principle!). But can you actually take an action that affects the past? My speculations on that are no better than anyone else's, but one must distinguish between whether it is possible in principle, versus whether it is practical, and I agree with adiffer that there does not appear to be any reason to think it's practical (plus if it were practical, we'd most likely have ample historical evidence of it by now! Not to mention the logical paradoxes.) You'd be better off shooting for the Jurassic Park scenario if you want to actually walk amongst dinosaurs (and look what happened to those people!)

Scientific truth can be a *****, can't it?

MrClean
2005-Oct-16, 02:06 PM
I'd have to say no, because the past no longer exists.

Well, actually the past does exist, but it's now the present. In other words, the past did once exist as the past, but it no longer does; it now exists as the present, and one day it will exist as the future. I hope that's clear.


Thanks, now I've gone all crosseyed!

SolusLupus
2005-Oct-16, 04:52 PM
Serious note: I really should look into what theorists really have to say on theoretical time travel. Personally, I'm skeptical of such ideas, but I'm too lazy to do a lot of reading on it.

Silly note: The Hitchhiker's Guide to the Galaxy had something to say on time travel. To paraphrase: The problem isn't with being your own father/mother. Any well-adjusted family can overcome that problem... The problem is with grammatical references, such as future-past-future participle phrase...

In the webcomic "Bob and George", they put it the best way.

"I hate time travel" :)

gzhpcu
2005-Oct-16, 05:09 PM
Look at this:

http://news.bbc.co.uk/1/hi/sci/tech/4097258.stm


"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.

So, if you know the present, you cannot change it. If, for example, you know your father is alive today, the laws of the quantum universe state that there is no possibility of him being killed in the past. "

parallaxicality
2005-Oct-16, 05:42 PM
There is a difference between scientific possibility and logic. Time travel may be physically possible (assuming current physical theories are correct) but it violates logic, and therefore I do not believe it is possible.

Sticks
2005-Oct-16, 06:04 PM
Look at this:

http://news.bbc.co.uk/1/hi/sci/tech/4097258.stm


"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.

So, if you know the present, you cannot change it. If, for example, you know your father is alive today, the laws of the quantum universe state that there is no possibility of him being killed in the past. "

This is just another presentation of The Chronology Protection Conjecture (http://en.wikipedia.org/wiki/Chronology_protection_conjecture)

SolusLupus
2005-Oct-16, 06:36 PM
(I need to ask people how they usually do their quotes)


From BBC NEWS

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.

I find this statement amusing. If our pasts changed, would we really notice? This seems to make that assumption - that every change would be noticeable. I mean, if history was changed, why should anyone in the future recognize that change? Since, for us, the future is different, but for the future, the past is normal for them...

In short, for all we know, our pasts are changing every second of the day. But we might well NEVER KNOW, for our memories can very well be changing to fit that!


From Professor Greenberger

You go back to kill your father, but you'd arrive after he'd left the room, you wouldn't find him, or you'd change your mind

Now, this is something that irks me. This is almost like backwards destiny - that, even if you could go back to the past, some "hand of <insert something here>" would affect you and your personal choices in order to get things into an orderly fashion.

That... well, it suggests something, for sure, and it fits nothing that I care to believe.

adiffer
2005-Oct-17, 12:44 AM
If a violation of some dialect of mathematics were enough to make something physically impossible, we would get trapped pretty fast. We used to think there was one kind of geometry and discovered later an amazingly rich field of possibilities. The same applies to logic, so don't cling to it too much.

Mathematicians are bright people. They come up with all sorts of crazy constructs that enable us to comprehend and speak the patterns we observe in reality. Time travel ideas are tricky ones because we are used to languages with verbs that have built in time senses. Drop that bias and time is easier to understand. Was, Is, and Will Be are all the same thing that way.

Ken G
2005-Oct-17, 01:41 AM
And then there's the parallel universe idea, which is that you can go back in time but you won't actually find the same thread that is your own past. To do so would be like finding a needle in a haystack. Instead you'll find some other thread where things could be quite different, and the future of that time could be radically altered by your presence, but that future would be distinct from your own past. Still, I say if it were practical, we'd have seen it by now. Sort of the same argument against interstellar space travel, but I guess that's another "thread".

aurora
2005-Oct-17, 04:18 AM
I seem to remember that Hawking has a bet with someone, forget who, about whether time travel is possible.

Ken G
2005-Oct-17, 04:40 AM
I've heard of a bet where Hawking claimed that black holes, via creation and evaporation, could cause information to disappear, in apparent violation of the second law that says information (i.e., entropy) must not decrease. Is that related to the time-travel idea you refer to? Perhaps it is, via the issue of entropy defining an arrow of time. This is really tough sledding, because you have to unite gravity theory with quantum mechanics, and the reference frames are really hard to keep track of as well. It makes my head hurt. Hawking has since changed his opinion, but no one really understands why yet. But let's face it, this is all angels-on-the-head-of-a-black-hole stuff, I don't think I'm out on a limb to claim that reversing time's arrow, in the sense of being able to affect one's own past, is not a possibility in humanity's present future.

gzhpcu
2005-Oct-17, 08:07 AM
If Everett's "many worlds" scenario is correct, you can go back to the past, change what you like without changing the present, because you fork out into another universe.

Ken G
2005-Oct-17, 12:38 PM
Which presupposed that the simple act of going back in time won't cause you to fork into a different past to begin with, which would be a forking nuisance.

Candy
2005-Oct-17, 01:24 PM
From Brian Greene’s The Fabric Of The Cosmos, he states no to Time Travel to the Past.

He lists a ton of names for the earliest relativity papers with relevance for time machines.
- 1937 by the Scottish physicist W.J. van Stockum
- 1949 by a colleague of Einstein’s at the Institute for Advanced Study, Kurt Gödel.
- 1970s, Frank Tipler reanalyzed and refined van Stockum’s solution.
- 1991, Richard Gott of Princeton University discovered another method for building a time machine making use of so-called cosmic strings (hypothetical, infinitely long, filamentary remnants of phase transitions in the early universe).
- Recently, Kip Thorne and his students at the California Institute of Technology make use of wormholes.

Greene’s books are great for the layman!

ZaphodBeeblebrox
2005-Oct-17, 01:28 PM
I seem to remember that Hawking has a bet with someone, forget who, about whether time travel is possible.
Kip Thorne

Same Guy, he Made The Penthouse, Black Hole Bet, with ...

:dance:

Maddad
2005-Oct-18, 12:55 AM
I liked your first post, Ken.

Just a thought I've been mulling over for several days. I've been considering the implications of intense artificial gravity to counter the move into the future caused by sustained relativistic speeds. However, if you didn't just exactly balance movement into the future, but insted used additional gravity, then you might indeed be able to to move into the past. Be there; not just see it. It brings up though a host of issues, not the least is what we mean by time, and what happens to causality.

ZaphodBeeblebrox
2005-Oct-18, 05:00 AM
I liked your first post, Ken.

Just a thought I've been mulling over for several days. I've been considering the implications of intense artificial gravity to counter the move into the future caused by sustained relativistic speeds. However, if you didn't just exactly balance movement into the future, but insted used additional gravity, then you might indeed be able to to move into the past. Be there; not just see it. It brings up though a host of issues, not the least is what we mean by time, and what happens to causality.
The Only Issue Is, you Still Have to Accelerate, ALL, Of That Simulated Mass.

This Would Tend to Bring It, Into The Same Reference Frame; Thus Negating The Buffering Effect.

Also, Natural Gravitational Fields, Don't 'Cause Time-Like Curves, Except Through Massive Curvature; Why Should Artificial Fields, Be Any Different?

Ken G
2005-Oct-18, 08:05 AM
It is possible that the only way to really understand time would be to actually go back in it and see what happens, if that is in fact possible. Inasmuch as going back in time would represent a totally new experiment, it is likely that none of our present theories could predict the result with confidence. The more important issue is will we ever know enough to build the technology that can do it, and then see what happens next. My money says nope, but that shouldn't deter the intrepid dreamer.

Sticks
2005-Oct-18, 11:14 AM
When I was younger I did a sci fi serial on our main frame, where I had the idea of using some device that would react certain particles to produce accelerated anti-chronons. which would radiate outside of a defined sphere. The universe outside the bubble would then be driven backwards, whilst those inside the bubble continue to go forward as normal. Hence you effectively have a bubble moving backwards using some form of temporal Newtons third law of motion.

In the story line the device itself stayed in the present, so the hero had to track down the earliy experimental device, create a bubble outside of which accelerated chronons out into the universe, to overdrive it back to the present.

You can obviously rip that mechanism to shreds, but at the time it seemed as good as any, and the story line was to get as many in jokes ans side swipes out as possible.

wrt paradoxes, I used the idea of the predestination paradox, i.e the original history only unfolded as it did because of the person travelling to the past. A bit like that scene in the third Harry Potter movie where the Harry Potter who travels into the past creates the shock wave that takes out the wraiths, that he had thought his father had done, sort of.

beskeptical
2005-Oct-18, 05:14 PM
I'd have to say no, because the past no longer exists.

...How do you know that?

Time is a dimension. We can travel around in the 3 spatial dimensions and haven't yet traveled backward in the time dimension. But does that mean the past side of the time dimension isn't there? We can see back in time when we look at the light that left the past.

I consider future time as the edge of the Universe everyone usually thinks of as non-existent. Past time gets us to the center of the Universe which also doesn't exist apparently within the 3 spatial dimensions. Viewed in that conceptual version, whose to say exceeding the speed of light won't allow you to travel in the time dimension?

SolusLupus
2005-Oct-18, 05:21 PM
The problem that I have with travel to the future involves the fact that I don't like the idea of destiny.

My problem with travelling to the past, is that a lot of people like to make it a "reverse destiny" - as if there's no real way you can alter things there because something stops you somehow.

Maybe mathemeticians and physicists really can predict that we can go into the past or the future in a reasonable way. Heck, in my science fiction story ideas, I investigate my own imagination of time/dimensional travel (though in a fictional sence). Still, a lot of times, the ideas by theoretical physicists can be misinterpreted and misrepresented, and I'm VERY skeptical in general when it comes to time travel.

Argos
2005-Oct-18, 05:40 PM
Probably one should distinguish between "seeing" the past, and "being in" the past. You can see dinosaurs if you can get the light they emitted to bounce off something 100 million light years away and come back (in principle!).

Yes, by a strong G field, for instance. Many people (me, me and me) believe that gravitational mirrors are possible, exactly like gravitational lenses.

gopher65
2005-Oct-19, 03:21 AM
The problem that I have with travel to the future involves the fact that I don't like the idea of destiny.

This morning I had Cheerios for breakfast. I made the decision to eat the Cheerios. Tomorrow when I wake up I will make a choice about what I will eat for breakfast. What will it be? It is my choice. Is it any less of a choice because it was made in the past rather than the future? Regardless of when I make a decision it is still *my* choice. It doesn't matter when it was made, or even if it is changable.

Chuck
2005-Oct-19, 04:21 AM
I invented a commercially practical time machine, but my first customer turned out to have a prior patent.

ZaphodBeeblebrox
2005-Oct-19, 05:30 AM
I invented a commercially practical time machine, but my first customer turned out to have a prior patent.
Same HERE!!!

Turned Out, To Be, My Future Self!!!!

Sticks
2005-Oct-19, 10:54 AM
Which they both nicked off of my future descendant :naughty:

ZaphodBeeblebrox
2005-Oct-19, 11:04 AM
Which they both nicked off of my future descendant :naughty:
Wasn't he, a Space Ship Thief ....

Who Assasinated, The Emperor of Xena?

:razz:

Sticks
2005-Oct-19, 11:10 AM
Not yet

SolusLupus
2005-Oct-19, 12:41 PM
This morning I had Cheerios for breakfast. I made the decision to eat the Cheerios. Tomorrow when I wake up I will make a choice about what I will eat for breakfast. What will it be? It is my choice. Is it any less of a choice because it was made in the past rather than the future? Regardless of when I make a decision it is still *my* choice. It doesn't matter when it was made, or even if it is changable.

(Man, it's hard to sound serious when looking at that goofy gopher avatar. Erm, no offence. :) )

Yes, that's true and all... and I guess going into the future is all well and good and perhaps doesn't denote destiny. Though then there's the fact that if it's unchangeable, and you DO go into the future, and THEN go into the past, but can't change the future... well, it seems silly to me, because then that DOES denote destiny.

Not only that, but going into the past and having "forces beyond your control" affecting your actions to the point where you can't change the present does denote a sense of destiny. And I do mean this in the mystical way. Something is trying to prevent you from changing the effective "future" if you go into the past, and it will nudge you and you will mystically "change your mind" so you don't change your future present.

That just seems silly to me, hence, I'll probably always be skeptical of time travel.

Also, another reason I'm skeptical is because of the assumptions. It's assumed that, because we don't notice the shifts of the past, then there must BE no shifts in the past. They don't even seem to factor in the fact that they could be happening without us noticing. Assumptions, in general, always leave me feeling not only annoyed, but skeptical about the subject at hand.

eburacum45
2005-Oct-19, 03:03 PM
I think there are about four permutations of the relationship between causality and time travel; if it really is possible to use wormholes for time travel as Kip Thorne suggests, or if any other method is possible then one of these four scenarios is likely to apply.

1/ If time travel can only lead to events which have already been observed to happen, then the situation is called consistent;
this is the Novikov self-consistency (http://en.wikipedia.org/wiki/Novikov_self-consistency_principle) theory of time travel, and eliminates the Grandfather paradox.
You can go back in time, but you can't kill your grandfather no matter how hard you try. Backwards time travel is deterministic, forward travel (and the normal passage of time) are probabilistic.

2/ Another solution would be that backwards time travel is impossible;
That is the second commonly quoted solution to the Grandfather paradox; impossibility (known as the 'boring physics' conjecture). In practice this could mean that any arrangement of wormholes which allowed time travel might collapse, due to a flux of virtual particles, or alternatively an event horizon might form to prevent such travel (see Cauchy Horizon (http://en.wikipedia.org/wiki/Cauchy_horizon))

3/ Mentioned earlier in this thread, the 'Many Worlds' hypothesis where time travel allows events to be changed, thereby creating a whole new, parallel timeline. This Many-Worlds scenario seems to be going out of favour with quantum physicists, although I am not sure why.

4/ the 'radical rewrite' conjecture in which you can go back in time, rewrite history, but there is only one timeline which is rewritten by your actions (with a single blind loop representing the original unaltered timeline, which disappears).
I can't quite see how this would work in practice, but it seems to be the basis for many fictional time travel stories. This is sometimes called a 'mutable timeline (http://en.wikipedia.org/wiki/Time_Travel#Mutable_timelines)'
-----------------------

Let's examine what happens if you try to change history, using each of these conjectures in turn;

If the first conjecture (the Novikov self-consistency conjecture) is correct, you go back in time but nothing you do can change the past. If you try to shoot your grandfather your gun jams, and so on. So when you go home nothing has changed.


If the second conjecture is correct, (the 'boring physics' conjecture) then your time machine doesnt work, so you can't go back anyway.

if the third option (the well-known Many Worlds Hypothesis) is correct, you can change history, and create a new timeline; if you go to the future of the new timeline, everything has changed, but your own original timeline exists somewhere in the multiverse, and you might one day be able to find it one day, perhaps by 'sliding' sideways through the many versions of history.

If the fourth option applies (radical rewrite) you can go back, change the world, but by doing so you destroy the timeline you came from, and create a paradox- your own personal history has been destroyed, and you never got into the time machine in the first place. So where did you come from?

Eroica
2005-Oct-19, 03:07 PM
How do you know that [the past no longer exists]? Because everything that was needed to make up the past - all the photons, protons, neutrons, electrons, etc - are currently being used to make up the present! ;)

gopher65
2005-Oct-19, 03:08 PM
My avatar is meant to be goofy and silly hehe. No offence taken. You should have seen the other one I considered using. It was a gopher with a RPG launcher;)

I don't personally believe the past is immuntable. I mean, if space can be warped and twisted then time should be able to have the same thing happen to it (in both directions). Just my opinion though. I have no evidence to support that conjecture.

parallaxicality
2005-Oct-19, 03:15 PM
The problem I have with the "many worlds" interpretation as applies to time travel is that the universe you enter depends on your creating time travel, yet it doesn't matter whether time travel was created in this new timeline or not, therefore the events in one universe are dependent on the events in another. How can these timelines have always existed, when they couldn't have existed before the invention of time travel?

parallaxicality
2005-Oct-19, 03:15 PM
The problem I have with the "many worlds" interpretation as applies to time travel is that the universe you enter depends on your creating time travel, yet it doesn't matter whether time travel was created in this new timeline or not, therefore the events in one universe are dependent on the events in another. How can these timelines have always existed, when they couldn't have existed before the invention of time travel?

Disinfo Agent
2005-Oct-19, 03:25 PM
Because everything that was needed to make up the past - all the photons, protons, neutrons, electrons, etc - are currently being used to make up the present! ;)'What's gone and what's past help should be past grief.' William Shakespeare, The Winter's Tale. :)

Sticks
2005-Oct-19, 03:29 PM
Time travel violates the 1st Law of thermodynamics anyway :naughty:

SolusLupus
2005-Oct-19, 04:05 PM
Hmm... I think that the "radical rewrite" still has potential. Consider something:

The past does change, so does the future. And the change is set in stone, and possibly you, as the time traveller dude, disappear. Or suppose you don't. But does that necessarily mean that the universe has to say "Wait a minute..."?

I mean, consider something for a moment: Everything in the universe has a cause and effect. If you cause a change in the past, the effect could be a change in the future - but the universe isn't under any obligation to "remember" each change and fidget, and try to make it all fit together perfectly.

However, since there aren't a lot of time travelling buffs in today's world getting rich, then most likely the time traveller would get wiped out with a change. That is, if this idea is true.

However, this brings up an interesting idea:

If time travel would be possible, why don't we see time travellers arriving at some specific date over and over, trying to fix up history? Or even just getting rich off "future inventions"? I mean, one can shout conspiracy and say that they merely don't show off the fact that they're in the future, but I'm sure that at least one time traveller would be obvious, and would have also brought stuff to back up his claims.

Disinfo Agent
2005-Oct-19, 04:34 PM
A temporal version of Olbers' Paradox? But then, who would want to travel in time to this day and age? ;)

SolusLupus
2005-Oct-19, 04:47 PM
Bah, I would. Just to freak my mom out.

On another note:

"The idea of reincarnation comes from the cultural idea(l?) that there is more to this world that you can taste or touch. Unfortunately, and this is the main point: Time. You think of time as a straight line, like a road, or a train track.
The metaphor is seductive in its ease. The world was flat until we discovered that it was round" (Note: Probably didn't get all the words right)

The introducing voice in the song "Timeline" by Machinae Supremacy. Very cool song overall. And no, I'm not trying to make a point with the quote. Music is not necessarily my philosophy.

(I still like the song though :) )

eburacum45
2005-Oct-19, 05:13 PM
I think it resembles Fermi's 'paradox' rather than Olbers' paradox-

if time travellers exist- where are they?

SolusLupus
2005-Oct-19, 05:16 PM
Maybe the Langoliers ate 'em.

Disinfo Agent
2005-Oct-19, 05:20 PM
I think it resembles Fermi's 'paradox' rather than Olbers' paradox-

if time travellers exist- where are they?Quite right (http://www.bautforum.com/showthread.php?t=32947&highlight=Fermi), though there's some similarity between the two. I got my paradoxes mixed up.

publiusr
2005-Oct-19, 06:05 PM
Check out page 46 of the NOV 2005 Popular Science! Time travel without wormholes A very good issue all around--including the use of spy cameras for landscape photography:

www.gigapxl.org (actually film put on computer--take that lousy CCDs!)

If you aren't afraid of the hantavirus, maybe astronomers here could use the old Vista Galactica set up (P. 66, same ish).

When will they rebroadcast that special of the man who lost his father and came up with a 'time machine' that consisted of a spiril path of lasers? It was time travel communication device of sorts.

Time to get a bookie.

trinitree88
2005-Oct-20, 01:28 AM
I liked Dilbert's take on it about a week ?? ,ago in the Boston Globe.....guy at flea market.....little portapotty type of room with door....sign on door....for only 10 bucks...stepping inside my time machine will take you 1 minute into the future in only sixty seconds. ( and PT Barnum thought he might be out of business by now )....gotta get me one of those little rooms.
If time travel were possible, ever, in either direction,...they'd be here now. :think: Ciao. Pete

ZaphodBeeblebrox
2005-Oct-20, 08:27 AM
My Idea, Along These Lines:

EVERY Genocidal Dictator, in History, Should Have had Thousands of Snipers, All Targeting them, from Age Two, Onward!

Adolf Hitler, in Particular, Should Have Been, Unable to Take a Step, Without Someone Taking a Shot, At him!

As for Saddam Hussein, War Should Have Been Breaking Out, Outside his Childhood Home, As his Supporters and his Detractors, Waged Open Conflict, Over his Eventual Fate!

This All, Didn't Happen; Therefore Time Travel, is Impossible!

Disinfo Agent
2005-Oct-20, 10:57 AM
My Idea, Along These Lines:

EVERY Genocidal Dictator, in History, Should Have had Thousands of Snipers, All Targeting them, from Age Two, Onward!Or every democratic leader. :eek:

ZaphodBeeblebrox
2005-Oct-20, 12:05 PM
Or every democratic leader. :eek:
Possibly ...

Not as Polarizing, though ...

I Mean, you Don't Have To Be, a Temporal Engineer, To Know, What The Mossad, Would Do, If they Ever, Got their Hands, On a Time Machine ...

KILL Hitler!!!

Argos
2005-Oct-20, 12:10 PM
About temporal engineering I suggest Isaac Asimov´s novel "End of Eternity".

Sticks
2005-Oct-20, 01:37 PM
You might have temporal agents policing the timelines to preserve history, a la Time Cops and Star Trek Enterprise.

Grey
2005-Oct-20, 01:45 PM
Adolf Hitler, in Particular, Should Have Been, Unable to Take a Step, Without Someone Taking a Shot, At him!I recall a short story in which the protagonist goes back in time to assassinate Hitler, only to be intercepted and taken to an auditorium filled with time travellers who had all come to do the same thing (all in humorously inaccurate disguises, like the one who apparently thought that dressing in Lederhosen would allow him to blend seemlessly into 1930's Germany). Hitler then comes to speak with them, and seems genuinely puzzled about why all these people seem to have gone to such great lengths to kill him. The twist ending was that the protagonist suddenly realizes that Hitler was known for his ability to sway people, decides he's not going to be taken in, and manages to grab a gun from a guard and shoot Hitler. We then hear some of the other leaders arguing about how, to preserve the stability of the country, they'll have to put the double in Hitler's place, even though they know he's mentally unbalanced...

Sticks
2005-Oct-20, 03:56 PM
This is known as the Pago paradox, which was referred to on Startrek Voyager

By going into the past you cause the event to happen that you sought to prevent.

In Star Trek First Contack the Borg go back to prevent the first warp flight by Cockrane, only for Enterprise to follow them through , prevent them and make sure the flight is actually succcessful.

gopher65
2005-Oct-20, 07:55 PM
I suppose that you could think of objects travelling though time as having some sort of inertia. What I mean is this: When you try to move an object in 3 dimensions it requires an input of energy to overcome the object's inate inertial mass. Carrying that forward, I make the assumtion that objects in 4D behave the same way. IE if you travel back in time and interact with your father with the intention of killing him, you will have to make a huge effort of some kind in order to overcome his 'temporal inertia'. If you don't input sufficent energy in the exact direction that you needed to, you will not achieve the result that you wanted.

To me (if this were true, I have no idea if it is or not) this would seem to indicate 2 things. 1) it is possible to change the past, but it is very difficult to overcome the inertia of an object moving through time, and 2) ANY movement through time, whether backwards or forwards, will alter time. However, because of inertia any 'butterfly effect' changes caused by your travel through time (or possibly simply by your observation of events) would quickly subside.

To me this is the common sense way for time travel to work (if it does work). But I think we all know that not everything works the way common sense dictates it should.

EDIT: Hmmmm. Now that I've thought about this a bit more I think that inertia would make changing time practically impossible. In 3D you can select a single object and move it. You apply energy to that single object and as little as possible to everything else. But in 4D any attempt to move a single object would inevitably cause a ripple effect. Therefore any attempt to move a single object would require you to move a great many objects. Going back in time and killing Hitler's mother would effectively move every single person (and many other objects) on the planet for the entire future history of the planet. Can you imagine how much energy that would take?

Sticks
2005-Oct-20, 08:57 PM
Time travel into the future is possible and has been proved.

When an object travels at relevatistic speeds, it experiences time dilation as a consequce of the special theory of relativity, and for it time slows down. This is the rationale behind the twin paradox / thought experiment.

As to the proof, they found certain particles, which decay into other particles were "kept" longer when they were accelerated in particle accelorators. Also they have done experiments with atomic clocks, where you synchronise the two, and fly one in an areoplane. On return, there is a difference, as predicted by the special theory of relativity.

The other way of "time travel" to the future would be some form of chryogenic stasis.

The one drawback with trips to the future is that they are oneway trips only.

How Kirk did it, (Backwards time travel), in Startrek IV by some clever slingshot around the Sun is a mystery to me. Any clues here, or was there something I missed?

TobiasTheViking
2005-Oct-20, 09:16 PM
How Kirk did it, (Backwards time travel), in Startrek IV by some clever slingshot around the Sun is a mystery to me. Any clues here, or was there something I missed?
He did it with dedication and a hudge budget for EFX.

Also, it was a TV show.

*snigger*

pghnative
2005-Oct-20, 09:37 PM
Didn't see it in the thread yet, but I believe Hawking's argument against time travel into the past is the fact that we do not see tourists from the future.

That's a bit hard to argue against.

JohnD
2005-Oct-20, 10:12 PM
Probably the best experiment to test if time travel is possible was the MIT Time Travel Convention in may this year. See:http://web.mit.edu/adorai/timetraveler/

The Convention WAS the experiment, as delegates were requested to leave invitations in their own habitats, in as durable a form as possible from acid free paper to baked clay.
No one from another time turned up. Strong evidence for the nul hypothesis.

John

TobiasTheViking
2005-Oct-20, 10:35 PM
Not really, all it shows is that either it isn't possible, or there are certain rules involved.

It isn't really possible to disprove it.

parallaxicality
2005-Oct-20, 10:55 PM
He did it with dedication and a hudge budget for EFX.

Also, it was a TV show.

*snigger*

No, it was a movie. :)

The idea basically was that you travel to warp ten (the new extended "light speed" in the Trek universe), then slingshot round the sun so that you will have no choice but to go faster, ergo, you go back through time.

Candy
2005-Oct-21, 12:16 AM
Didn't see it in the thread yet, but I believe Hawking's argument against time travel into the past is the fact that we do not see tourists from the future.

That's a bit hard to argue against.
I never thought of it that way before.

ZaphodBeeblebrox
2005-Oct-21, 01:43 AM
Didn't see it in the thread yet, but I believe Hawking's argument against time travel into the past is the fact that we do not see tourists from the future.

That's a bit hard to argue against.
My Favourite, Counter-Arguement:

Some Time, in The Future, Everyone is Having LOTS of, Ahem, Sensual Fun!!!

No One, From Still Later, in The Future, Would Bother, Going Back, Any Further!!!

SolusLupus
2005-Oct-21, 01:51 AM
...


My Favourite, Counter-Arguement:

Some Time, in The Future, Everyone is Having LOTS of, Ahem, Sensual Fun!!!

No One, From Still Later, in The Future, Would Bother, Going Back, Any Further!!!

....

....

Someone invent a time machine to the future, please.

Eroica
2005-Oct-21, 04:02 PM
Time travel into the future is possible and has been proved.
But this is the sort of time travel we engage in every second of our lives. It's not really the same as time travel a la H. G. Wells.

Shilappadikaram
2005-Oct-24, 01:02 AM
The Only Issue Is, you Still Have to Accelerate, ALL, Of That Simulated Mass.

This Would Tend to Bring It, Into The Same Reference Frame; Thus Negating The Buffering Effect.

Also, Natural Gravitational Fields, Don't 'Cause Time-Like Curves, Except Through Massive Curvature; Why Should Artificial Fields, Be Any Different?Maybe not. If your gravity generator is on board your ship, then your ship will continuously fall forward into the field you create ahead of you. If what you need is space curvature, then why not generate an intense field? It serves two purposes. One is that it quickly (in your frame of reference) gets you moving at extremely high speeds.

I can see an objection based on being left with an unmanagable gravity gradient. However, if the fied's center is well enough ahead of the ship, then the gradient usable back on board. The difficulty would be that you would need an even stronger field in total. Hey, I never said we already had this technology ready to pop into an X-22 fighter/interceptor.

beskeptical
2005-Oct-24, 06:59 AM
Because everything that was needed to make up the past - all the photons, protons, neutrons, electrons, etc - are currently being used to make up the present! ;)Ooohh, I like that reasoning. I'll have to figure that into my Universe contemplating now.

Let's see....if it isn't a wave or a particle until it's observed, or was that a dead or alive cat, then can we observe those particles, etc. in their past state even if they are observable in their current state at the same time?

Do we really understand the nature of time and how it interacts with particles, etc.? Is it possible our concepts of these things may be unnecessarily limiting our imagination of the possibilities?

beskeptical
2005-Oct-24, 07:11 AM
As to, "there would be time travelers if it were to be invented in the future", whose to say we aren't in front? In other words we might invent time travel in the future but that future has yet to occur. While after it occurs then the people in the past (us) will see the time travelers.

Also, perhaps time travelers will be out of sync in some way and will be able to observe the past, as has already been mentioned, but will not be able to interact with it since the past may have some other form. Right now we see the past as light but not the actual source that emitted the light. Even if you could see the source of the light you couldn't necessarily touch it. It would still be just the light (or other frequencies of the electromagnetic spectrum), that was observable.

hammo1j
2005-Oct-26, 11:35 AM
Thank-you ebaracum45 for your excellent analysis of backward time travel.

Self consistency.
Impossible.
Many worlds.
Mutable time line.

I suppose sideways time travel would be a journey into one of the many possible worlds.

One twist upon backwards time travel would be massless time travel such as in the TV series Quantum Leap whereby the person's identity/soul is the only thing to travel. This is also the re-incarnation does not necessarily move you into a body that is in the future scenario.

If this universe was a VR simulation, as some point out it might be, this would be achievable.

I have a feeling that past viewing may be more practical as in Arthur Clarkes novel the Light of Days gone by.

Lianachan
2005-Oct-26, 12:46 PM
If you visit the island of Scalpay (off the east coast of the Hebridean island of Harris) you would swear you'd travelled backwards in time at least 50 years.

Candy
2005-Oct-26, 08:11 PM
If you visit the island of Scalpay (off the east coast of the Hebridean island of Harris) you would swear you'd travelled backwards in time at least 50 years.
Scalpay (http://www.scalpay.com/) looks very nice.

Lianachan
2005-Oct-27, 12:12 AM
Scalpay (http://www.scalpay.com/) looks very nice.

That seems to be a dead link. This (http://www.undiscoveredscotland.co.uk/scalpay/scalpay/) one tells you a bit about the place, and has a liberal dusting of photographs. I know Scalpay very well, having lived in Tarbert on the Isle Of Harris for a few years. Looks very nice? To quote Obi-Wan Kenobi: Your eyes can deceive you, don't trust them!

Actually, it's changed considerably (and inevitably) since the bridge was built and isn't as bad these days (I was there this summer).

John_Charles_Webb
2005-Oct-30, 01:30 AM
I want to be able to see dinosaurs, but from what I've heard, time travel is only possible if you're heading towards the future.

My understanding of Einstein is that many of his quantum theories (relative to time) include "velocity". Since negative velocity does not exist we can only go in one direction.... not backwards in time.

publiusr
2005-Nov-02, 07:55 PM
Didn't see it in the thread yet, but I believe Hawking's argument against time travel into the past is the fact that we do not see tourists from the future.

That's a bit hard to argue against.

On the contrary--if I were from the future, I would look like just another Joe-Q-Six pack walking down the street. I might be rather 'lucky' with a bookie knowing game results in advance, but I wouldn't stand out.

My only give-away is that my time machine would have to be a spaceship--so if I can aerobrake parachute in without drawing any attention (in an under-developed country, perhaps), I could catch a ride to the US, get a fake ID like anyone else, and become your next door neighbor. Or the reporter at a White House press briefing. Or a poster here.

ZaphodBeeblebrox
2005-Nov-02, 08:27 PM
On the contrary--if I were from the future, I would look like just another Joe-Q-Six pack walking down the street. I might be rather 'lucky' with a bookie knowing game results in advance, but I wouldn't stand out.

My only give-away is that my time machine would have to be a spaceship--so if I can aerobrake parachute in without drawing any attention (in an under-developed country, perhaps), I could catch a ride to the US, get a fake ID like anyone else, and become your next door neighbor. Or the reporter at a White House press briefing. Or a poster here.
Who says ...

Someone Hasn't, ALREADY Done That?

:shifty:

publiusr
2005-Nov-02, 09:03 PM
So you want I should give you the USC vs UCLA game results now?

ZaphodBeeblebrox
2005-Nov-02, 10:08 PM
So you want I should give you the USC vs UCLA game results now?
Naw ...

American Footbal, Doesn't Survive World War IV!!!

Now ...

Who Wants, Tomorrow's Lottery Numbers?

SolusLupus
2005-Nov-02, 10:10 PM
We're IN World War IV. WWI, WWII, WWIII was the War on Drugs, WWIV is the Iraqi situation (a lot of the world is getting involved, after all). At least, so says my psychologist.

ZaphodBeeblebrox
2005-Nov-02, 10:17 PM
We're IN World War IV. WWI, WWII, WWIII was the War on Drugs, WWIV is the Iraqi situation (a lot of the world is getting involved, after all). At least, so says my psychologist.
Corpus Christi, huh?

So ...

Will that Be One NUKE, or Two?

'Cause, I Think the City, Takes Five ...

SolusLupus
2005-Nov-02, 10:19 PM
World War Three and World War Four do not automatically entail nukes. That's just a myth contrived of anti-nuclear weapons activists.

In reality, the preference is more reliant on surgical procedures, using a scalpel, than destructive measures, such as boulders, for warfare. With the increasing instances of Urban Warfare, this holds doubly true. And when I meant "We're in", I didn't mean Corpus Christi, I meant the world ;) Though I realize that saying we're in WWIV is very shakey. I mean, the world isn't really getting involved, just a few major nations. However, the War on Drugs was more worldwide, I think.

Sticks
2005-Nov-02, 10:24 PM
Who says ...

Someone Hasn't, ALREADY Done That?

:shifty:

They tried

They were arrested by the Time Cops and sent back :naughty:

ZaphodBeeblebrox
2005-Nov-02, 10:46 PM
World War Three and World War Four do not automatically entail nukes. That's just a myth contrived of anti-nuclear weapons activists.

In reality, the preference is more reliant on surgical procedures, using a scalpel, than destructive measures, such as boulders, for warfare. With the increasing instances of Urban Warfare, this holds doubly true. And when I meant "We're in", I didn't mean Corpus Christi, I meant the world ;) Though I realize that saying we're in WWIV is very shakey. I mean, the world isn't really getting involved, just a few major nations. However, the War on Drugs was more worldwide, I think.
Actually ...

According to Historians, The Cold War, Will Likely be Refferred to, In Future History Texts, as World War III.

As for World War IV, NOT, Going Nuclear; a Future War, Is Not Likely, to Recieve that Monkier, Unless, It Either First Goes Nuclear, or, Has a Very Large Potential, of Doing So!!!

SolusLupus
2005-Nov-02, 10:49 PM
You may very well be right, then. So WWIII was the Cold War, and IV is the War on Drugs?

ZaphodBeeblebrox
2005-Nov-02, 11:10 PM
You may very well be right, then. So WWIII was the Cold War, and IV is the War on Drugs?
No ...

You're Kidding me, On The War on Drugs, Riight?

It Neither has the Troop Numbers, Nor The International Involvement, to Count as ANYTHING!!!

Let Alone, a World War ...

SolusLupus
2005-Nov-02, 11:11 PM
Bah :P

ZaphodBeeblebrox
2005-Nov-02, 11:12 PM
They tried

They were arrested by the Time Cops and sent back :naughty:
Hmmm ...

I Didn't See ANY Time Cops, Outside the Hitler House ...

Of 'Course, we Were Mostly, Jockeying for Position!

SolusLupus
2005-Nov-02, 11:14 PM
One possibility is that in the far far far future, people got tired of people messing with the past so much, that they invented a way to "bar" time travel. Sure, it takes some Ultratech, some Ultraknowledge, and such, but they were able to do it 'cause they were in the future, thus they had the magical tech

ZaphodBeeblebrox
2005-Nov-02, 11:29 PM
One possibility is that in the far far far future, people got tired of people messing with the past so much, that they invented a way to "bar" time travel. Sure, it takes some Ultratech, some Ultraknowledge, and such, but they were able to do it 'cause they were in the future, thus they had the magical tech
Or ...

It's Just NOT, Possible!!!

Of Course, There Is, Another Option ...

So, Anyone, Want Next Week's, Powerball Numbers?

SolusLupus
2005-Nov-02, 11:38 PM
Another possibility:

What if the energy required to go into the past would be so extreme, only private organizations could afford it? But they wouldn't want to effect the past too much, so they not only create a monopoly on it, but HEAVILY restrict trips to the past to apocalyptic battles a la sci-fi action movies?

Then, as we develop greater and greater energy sources, it's far too much of "tradition" to leave it in the hands of the private businesses, that the Government(s) of the future also restrict it to those corporations.

It might also explain the inexplicable success of certain companies, such as Microsoft, or IBM. A small company going astronomical in profits, and knowing just what to do about it...

TIME TRAVEL!

(What? I'm not on the Conspiracy thread? Darn.)

Grey
2005-Nov-03, 02:16 AM
What if the energy required to go into the past would be so extreme...A Thousand Paces has been fond of pointing out that the conversion between units of time and units of distance for special relativity is the speed of light. So that means that the amount of effort it takes to go one second into the past should be about the same as the effort it takes to travel 300,000 km.

SolusLupus
2005-Nov-03, 02:21 AM
Which is hard, right?

ZaphodBeeblebrox
2005-Nov-03, 05:00 AM
Which is hard, right?
Just a BIT, Yeah ...

Probably, Even More, Though, As It Requires a Speed Faster than that Of Light, to Achieve!!!

Pretty Hard, Don'tcha Think?

:think:

SolusLupus
2005-Nov-03, 06:31 AM
So there you go. It's so hard, private corporations are the first ones to be able to really do it, and they restrict every trip to themselves. Tradition is started, and there you go.

(Of course, there's the method in my stories, which involve cutting through dimensions and using other forces... but then again, my stories have a few fantasy elements, and I do admit it).

Grey
2005-Nov-03, 03:54 PM
Which is hard, right?
:)

SolusLupus
2005-Nov-03, 04:39 PM
Whaaat? I thought you all might need a chuckle or two ;)

publiusr
2005-Nov-03, 07:09 PM
Trans-temporal communication is about the only time travel we will see. Remember the Discovery Channel special on time travel with the helical laser grids that would allow a signal in the future to travel backwards to the time the machine was first tuned on.

There would have to be protocols set up to keep signals from riding over each other. If the machine were turned on Dec. 1 2015, future users could only send data back to Dec 1 on July 1, 2150. To reach Dec 2 2015, you would send data back on July 2.

Or different hours in the day would correspond to different years.

You would read the furthest one back then move toward your own time to get a grip on that timeline.

If a terrorist strike occurs, the next go round will not include that information as the tragedy has been prevented and dealt with. Then you begin again the next day and follow the same proceedure.

In this way, different realities are seen, and we will have videos transmitted back of terrorist strikes that we prevent--basically getting glipses of alternate universes and/or timelines.

On Dec 1 2017, the schedule will be as follows
Schedule
12:00 PM Only broadcasts from 12 PM for the yr.3050
1:00 PM -----yr 2450
2:00 PM ------yr 2250

etc.

This prevents signals from all trying to reach the very moment the machine is turned on.

At first, only messages in the near future are alowed, then far future messages on down the list, and so on. This way, the history of each timeline is preserved. If you go into the near future, then on to the next yr, you are limiting the utility of the machine, as a possible outcome has been lost to observation. You start as far in the future and work back.

As the 'now' reaches the time of transmission of the first message sent back, you send that message first and any changes that go to a silent partner in the earlier now. Shift changes are frequent to limit access and confusion.

Thats how we do it here at SG-8 anyway.

ZaphodBeeblebrox
2005-Nov-03, 09:11 PM
This, Of Course, ASSUMES, History is Mutable ....

What, If It Isn't?

How Would we React, to Glimpses of Horrors, we Are Never, Able to Change?

:think:

publiusr
2005-Nov-03, 09:13 PM
That would be only our timeline as our 'now' progresses.

You have a heart-attack before the signal from the future can warn you to cut down on fats.

ZaphodBeeblebrox
2005-Nov-03, 09:55 PM
That would be only our timeline as our 'now' progresses.

You have a heart-attack before the signal from the future can warn you to cut down on fats.
OR ...

You Make a Switch, to Less Fatty Foods, As a Result ...

Unfortunately, One Of your Alternatives, Is To Switch your Butter, In for Margerine; Which, Turns Out, To Be, Even Worse, For you!

publiusr
2005-Nov-04, 07:18 PM
Thats why I don't even bother with diets.
Before long, we will find out fiber is bad for you, and that steak and eggs and cigarettes hold a cure for aging.

Way I reckon, I'm just hoping that--if I do have a stroke or coronary, it will be so massive as to blow the top of my head clean off and save on the hospital bills.

Here's to more egg and cheese omlets--my staple.

SolusLupus
2005-Nov-04, 07:21 PM
I'm starting to replace vegetables for meat. I'll still have meat now and then, but I'm starting to really like my soymeat. It's yummeh, and it helps me keep healthy.

Also, exercise always helps your livelihood (at least, until we allow genetic engineering that allows for couch potatoes to be healthy just sitting there)

ZaphodBeeblebrox
2005-Nov-04, 08:35 PM
All This Time Travel Talk, Is Givin' me, Cabin Fever ...

I'm Going to The Hitler House, Tonight ...

Who Wants, To Join me?

:D

Sticks
2005-Nov-04, 10:33 PM
With the way you behaved, sorry I mean will behave when you get there, BTW terry is a drag act, but then I warned you last time but you did not or do not believe me.

This temporal mechanics gives me a headache

ZaphodBeeblebrox
2005-Nov-04, 10:54 PM
With the way you behaved, sorry I mean will behave when you get there, BTW terry is a drag act, but then I warned you last time but you did not or do not believe me.

This temporal mechanics gives me a headache
Well, There is ALWAYS, That Party, at The End of the Universe!!!

Just Remember, Deposit One Penny Now, And you'll Be Able, To Afford, The Huge Cover Charge, When you Get There!!!

Oh, and Terry Turned Out to Have, a Really Hot Granddaughter, About 50 Years, From Now, So, It's All Good!

Sticks
2005-Nov-04, 11:17 PM
That was what all the victims said about here after she had cleaned them out

ZaphodBeeblebrox
2005-Nov-04, 11:44 PM
That was what all the victims said about here after she had cleaned them out
What, Can I Say ...

Her Granddaughter, WILL Be, Really Popular!!!!

:D

Kemal
2005-Nov-07, 02:37 AM
I did not read the whole thread, so maybe this was asked already.

But does any method of faster than light travel always involve time travel as well? In other words does it always violate causality?

Grey
2005-Nov-07, 04:12 AM
But does any method of faster than light travel always involve time travel as well? In other words does it always violate causality?Yes. If you can travel from one point to another faster than light, you can always find a reference frame where you arrive before you left, at least, assuming special relativity is valid.

eburacum45
2005-Nov-07, 10:21 AM
As I understand it certain types of FTL travel, possibly including wormholes, will have a safe mode of operation where causality cannot be reversed.
See these space-time diagrams by Jim Wisniewski
http://www.orionsarm.com/whitepapers/wormholes_and_causality.html

This safe mode will have strict limitations, however.

Ken G
2005-Nov-07, 10:39 AM
So I think what Grey means is that so long as special relativity applies, which not only means it is a correct theory, but also implies you don't have wormholes, i.e., general relativity corrections. In practice, it's a little hard to keep a wormhole handy when you need one, I would imagine, but no doubt this thread is aimed at a high level of speculation!

Kemal
2005-Nov-08, 04:10 AM
The orion web site looks like a science fiction site, I'm not sure how much I'd trust it.

From the standpoint of causality violations, is FTL communications the same as FTL travel?

eburacum45
2005-Nov-08, 10:21 AM
It certainly is a science fiction site, but we do try to use real science at least half of the time...
the Kerr diagram Jim has provided should be accurate if Morris-Thorne wormholes were real and behaved in the way predicted by theory.
None of which is guaranteed, of course.

Sticks
2005-Nov-08, 10:48 AM
Any way I can send my consciousness back in time to say last Sunday morning aka "Tru Calling " or "Quantum Leap" style :(

SolusLupus
2005-Nov-08, 11:50 AM
Sending your consciousness back is kinda silly, if your brain isn't being sent back too. Memories and personality are decided by the brain make-up (and the two are dependant on each other, as well). Sending your consciousness back without the meaty brain would make you intellectually a newborn... even supposing that it was possible.

Sticks
2007-Oct-27, 10:38 AM
Bringing this thread back

What would be "nice" would be to lock on to an object at a certain point in time and space in the past, and bring it safely into the present. Like saving people on the Titanic, whose bodies were never found.

But I suspect this would violate the principal that you can never go back further than when the first time machine is ever switched on.

eburacum45
2007-Oct-27, 05:29 PM
Here's my updated page about the subject, including the concept of 'chronological collapse' which may or may not be accurate but it is mind-boggling to contemplate.
http://www.orionsarm.com/intro/WhyNoTimeTravel.html

KaiYeves
2007-Oct-27, 11:50 PM
What would be "nice" would be to lock on to an object at a certain point in time and space in the past, and bring it safely into the present. Like saving people on the Titanic, whose bodies were never found.
Yeah. All you'd have to do is catch a few passenger pigeons, come back to the present and start captive breeding and cloning. (Do both to hedge your bets)
How about holding onto an artefact of unknown provenance in the present and traveling back to when it was made, to find out if it really is fake?

Sticks
2007-Oct-28, 06:22 AM
But how would we do such?

All references to time travel seem to involves reference to black holes, worm holes, relativistic speeds, lots of radiation and parallel universe branching.

Anyone ever remember that TV show Time Tunnel?

Sean Clayden
2007-Oct-28, 10:55 PM
If you were able to travel 100 million lights years away faster than the speed of light and look back at earth then you could potentially see dinosaurs. Beings 100 millions of years away are seeing dinosaurs roaming around now. If only faster than c were possible.............

Wormholes and bending space are absolute tosh (rubbish)

Noclevername
2007-Oct-29, 12:07 AM
Wormholes and bending space are absolute tosh (rubbish)

And why is that? If they are consistent with known physics, then why not?

Sean Clayden
2007-Nov-01, 10:28 AM
Its great to invent these ideas, but thats all they are, bending space is a great theory but think of the logistics of doing so. Wormholes again are only theories of how we can travel to other parts of the universe quickly. We dont have the technology yet to travel to even our closest star in a sensible time frame, and if we could nobody would be alive when we got back to care.

Sticks
2007-Nov-01, 10:40 AM
Our closest star is the Sun

Noclevername
2007-Nov-01, 07:34 PM
Its great to invent these ideas, but thats all they are, bending space is a great theory but think of the logistics of doing so. Wormholes again are only theories of how we can travel to other parts of the universe quickly. We dont have the technology yet to travel to even our closest star in a sensible time frame, and if we could nobody would be alive when we got back to care.

So assuming the theories are correct, it will be a long time and require very advanced technology before we could use it. That hardly makes it "rubbish".

EDIT: It will be a very long time before we can even create experiments to find out how true or false the theories are.

i only ponder
2007-Nov-01, 09:45 PM
i'm hardly an expert in this (1st year physics student.. 6 weeks into the course..) but i've read about theoretical particles called tachyons that can travel faster than the speed of light. correct me if i'm wrong, but according to relativity since anything that travels at the speed of light cannot experience time, anything travelling faster than the speed of light must experience negative time, i.e. travel backwards though time. i don't know what that means for mass though (negative mass?)..

KaiYeves
2007-Nov-02, 12:14 AM
Welcome, i only ponder!
I love your signature line.

Sean Clayden
2007-Nov-02, 11:43 AM
So assuming the theories are correct, it will be a long time and require very advanced technology before we could use it. That hardly makes it "rubbish".

EDIT: It will be a very long time before we can even create experiments to find out how true or false the theories are.

Apologies. Was a bit over the top by saying it was rubbish. Ideas, theories are great but people can get a bit carried away with what is possible and impossible

Same as teleportation, beam me up scotty. Great idea, could it ever become possible ?

Doodler
2007-Nov-02, 01:02 PM
Same as teleportation, beam me up scotty. Great idea, could it ever become possible ?

Its already possible, just well beyond the capabilities of modern tech to transport a complex organism. Some principles of quantum computing use the same fundamental principles that would be involved in teleportation (quantum entanglement), just at a far simpler scale.

Noclevername
2007-Nov-02, 02:27 PM
In one version of Wormhole theory, teleporting by spatial discontinuity may be possible. This eliminates the limits on complexity inherent to quantum teleportation, as the entire pocket of space the complex objext inhabits is sent, rather than particle-by-particle. But that would require the same level of technology (and most of the same correct theories) as wormholes for Time Travel.

Sean Clayden
2007-Nov-05, 12:07 PM
In one version of Wormhole theory, teleporting by spatial discontinuity may be possible. This eliminates the limits on complexity inherent to quantum teleportation, as the entire pocket of space the complex objext inhabits is sent, rather than particle-by-particle. But that would require the same level of technology (and most of the same correct theories) as wormholes for Time Travel.

So the answer is no..............

Noclevername
2007-Nov-05, 02:14 PM
So the answer is no..............

So the answer is, we don't know yet.

Sean Clayden
2007-Nov-05, 02:49 PM
So the answer is, we don't know yet.

Question was is time travel possible, currently the answer is no. If the question was, will time travel be possible, then that could be construde as an answer.

Noclevername
2007-Nov-05, 03:50 PM
Question was is time travel possible, currently the answer is no. If the question was, will time travel be possible, then that could be construde as an answer.

Possible means "can it happen", not "can we do it". Lots of things are possible but not currently do-able by human beings. The Sun proves sustained fusion is possible. Photons prove lightspeed movement is possible.

ADDED: Right now we don't even have enough information to know whether time travel is even consistent with real-world physics, let alone feasible for human use.

Sean Clayden
2007-Nov-05, 04:39 PM
Possible means "can it happen", not "can we do it". Lots of things are possible but not currently do-able by human beings. The Sun proves sustained fusion is possible. Photons prove lightspeed movement is possible.

ADDED: Right now we don't even have enough information to know whether time travel is even consistent with real-world physics, let alone feasible for human use.

No then "currently". Unless further information/technology available.

Will come back and amend thread when time travel possible.

Noclevername
2007-Nov-05, 04:51 PM
No then "currently". Unless further information/technology available.

Will come back and amend thread when time travel possible.

Yeah, that's what I did. Oops, I've said too much... :)

Sean Clayden
2007-Nov-05, 05:10 PM
Yeah, that's what I did. Oops, I've said too much... :)

Now i will have to kill your ancestors :lol:

Noclevername
2007-Nov-05, 05:20 PM
Now i will have to kill your ancestors

I'm my own Grandpa. :lol:

Sean Clayden
2007-Nov-06, 06:30 PM
I'm my own Grandpa. :lol:

Lol

dgavin
2007-Nov-06, 11:02 PM
Actualy time travel may not be possible, but a space drive that moves through space/time might be.

From my understanding it's based on the new theroy that space is 6 dimensional (3 normal, 3 time)

It travels through all 6 dimensions to arive at a destination shortly after leaving the source.

Take this with a grain of salt, it was just something I read that was more speculation then anything.

Noclevername
2007-Nov-06, 11:04 PM
Actualy time travel may not be possible, but a space drive that moves through space/time might be.

Every space drive moves through spacetime. Everything that moves moves through spacetime.