Time Travel

[aldarius]

Hi all,

Ive just finish watching this show explaining the possibilities of creating a time machine.

world's first time machine

But the problem i have is this. In this part 5, he says that time travel to the past can only travel when the time machine is first built (3:48). Meaning if the machine is created now 2009, than in 100 years time 2109, the time machine can travel to only up to 2009 and not later, 2008 and beyond...

Why is this so?

 

[Born2bwire]

Because this current iteration of Fusetalk did not exist befoe 2009.

 

[Modelworks]

Time travel is extremely theoretical. Everyone has their own version of the rules. Some think time is linear and that you can't go back and change any event that would keep you from being born or from being able to travel to the past. Others think that time is like a tree with branches and that if you change one event you just branch off into another reality.

I like the idea that time is unique to each person. You could go back and kill your parents before you were born and you would still exist. I would be like an observer outside of the current time line around me.

 

[aldarius]

Even if the time machine does not exist in 2008, why cant i travel to, say 1995? Time travel is base on the bending of time and also possibility that my machine is with me when i reach.

I do agree that there may be a parallel universe, that what you do may not actually affect your current world, and there's also a possibilities you may not even be even to return to it.

But what he say about why i can't travel to 2008 and later ( in history) bucks me... sorry for me being stupid..

But time travel to me is not like a portal that can only exist when you have the same mechanism on both side to make it possible...

 

[Harvey]

Harvey's third law of physics;

The reason for time is to keep everything from happening at once.

I've found it's also useful for telling the drummer where "1" is.

 

[Cogman]

The guess is that if time travel to our current time was possible, then we would have seen someone by now. So instead of saying it is impossible to go to now, they like to try and say it is impossible to go to a time without a time machine.

The whole foundation is entirely hypothetical as there hasn't yet been an observed case of anything going any direction except forward in time.

Is it possible, who knows, I don't want to say it is impossible, as science has proven the impossible possible more then once. However, I do think that humans obtaining time travel capabilities is pretty improbable. It is right up there with traveling at light speed in the probability of us attaining it.

 

[spikespiegal]

The reason for time is to keep everything from happening at once.

:thumbsup:

With all due respect to egghead physics crowd, I persist that time is a human concept.

 

[Pernsworth]

I think about this a lot.

One thought is that if Time Travel WILL be possible, then we should be seeing the evidence of it right here & right now. If people at some point in the future will be traveling back to kill off their grandparents, then there should be some grandparents getting murderized.

One proof that it's not possible is that we do not see the results of future time travel right now.

However, in contrast to that, I also think about how immutable information is. Data exists without mass or energy and is therefore timeless. The medium of storage may be bound by the laws of physics, but the data itself is not. I wonder sometimes if this isn't the key to time travel, immortality, etc...

 

[dinkumthinkum]

Originally posted by: Cogman
The whole foundation is entirely hypothetical as there hasn't yet been an observed case of anything going any direction except forward in time.

QED permits -- I would say, demands -- that particles be able to travel either direction in time. And it is one of the most successful scientific theories of all time in predicting experimental results.

Not to get time travel hopes up. QED explains the propagation of light and interaction of electrons by surmising that photons travel over ALL possible paths (including below and above the speed of light, too). The observed effect is merely a sum of probability amplitudes which cancels out the "weird" paths leaving behind (usually) conventional behavior: traveling over a geodesic at the speed of light.

 

[jandlecack]

Originally posted by: spikespiegal

The reason for time is to keep everything from happening at once.

:thumbsup:

With all due respect to egghead physics crowd, I persist that time is a human concept.

I agree. What in our minds exists as time, years, fractions of seconds, changes "over time", progression, ageing and so on, is simply the way that the universe operates on a grand scale. It's just been inserted into our minds that there is something such as "time" which defines when what took place, and in theory leads to concepts like time travelling in the first place.

That's why I'm willing to say there will never be something like what we understand under "time travelling". It goes against the flow of the universe (in that...its flow is not up to us or any machine to manipulate). If at any point we'd witness something modifying the universe to this extent I'd say we'd have bigger issues than travelling through "time".

 

[destrekor]

Originally posted by: spikespiegal

The reason for time is to keep everything from happening at once.

:thumbsup:

With all due respect to egghead physics crowd, I persist that time is a human concept.

On that concept, I'll agree with you.
However, I think time is a reality of the universe, but not in any way that we so far currently understand.

I think everything regarding time is going to be theoretical, until someone finds some insane way to prove otherwise. Theorists propose the idea of 10 spatial dimensions (maybe more, depending on what theory you are looking at - String Theory has 10 dimensions). In the most simplistic explanation I could find (the real guts of the theory, don't look at unless you don't mind risking losing you mind due to sudden brain collapse or explosion I love astronomy and the concepts of astrophysics but cannot put the time into learning the material, i.e. a degree or three, oops long parenthetical statement) proposes that String Theory treats the other spatial dimensions as similar, in pure concept, to the three spatial dimensions we currently know. i.e. the 4th dimension is like the 1st dimension (a simple line existing nowhere specific), the 5th is like the 2nd (a 2D plane containing lines and points of lower dimensions), and the 6th dimension is like a 3D representation.
Our concept of time actually jazzes with that quite nice. Time, as what we define it, is a simple line. We believe we can essentially plot the beginning and the present on it, and fill in the blanks, but noone can say without a doubt, with evidence as proof, that the beginning of time as we know it, was actually the beginning. The Big Bang may not have been the first Big Bang, so that timeline would extend through that, theoretically.

So we have a line. We can create artificial points on that line.
If Time exists as a series of spatial dimensions, than I'd argue that the 6th dimension is just as manipulatable as the 3rd dimension. Meaning, we can change the shape of anything physical, we can alter dimensions, and for areas we don't know how to, we know how those dimensions can change through physical constants (stars, existing in the 3rd dimension, don't exist at that location, in the same shape, once they die and disappear).
If Time is a line, and time can also exist with 3 coordinates, it could be theorized that time could be manipulated as well. Lines could exist all over the place, strange groups of coordinates could create amazing/crazy 'shapes' in time. I'd say obviously different properties might exist in different dimensions, and thus the 'rules' might be different in such a 6th dimension. But I like to play around with the idea that, what if we learn to manipulate the 6th dimension? Create patterns that provide the ability to see time as we see fit.

This could also play nicely with the concept of going back in time, doing something different, and at that very moment creating a branch in time (or creating said branch before doing something) that allows both timelines to exist. All dimensions have effects on all the other dimensions, or at least have connections to each one, so one could argue that doing such a thing as creating branches in time (maybe they naturally exist already, for every single act/decision ever carried out? every possibility has an opposite, or multiple opposites, that create an infinitely complex web of timelines?). A time machine might then simply be the gateway to accessing these branches. A time machine, or at least the knowledge of the science, would be needed if jumping to a time that the machine didn't exist. Or... manipulate time some more so that the machine always exists, or that something like a worm hole always exists at a specific location in the 3rd dimension.

I could go on and on, so I'll leave it at that. It's all just fun playing with ideas, and forever will be... at least until the day science advances far beyond the present and we have very real proof one way or the other. The relationship between Time and Space is something we still don't have an accurate knowledge of. I'd like to imagine one day that might change, but humanity may never fully, 100% understand the Universe and all of its intricacies. Maybe one day we'll find a naturally existing link between different areas of time, or something that lends more to that debate. again, such as a wormhole. Still don't even have proof they are real, so we have a long time until we have any more information to credit/discredit many theories we have regarding the universe.

 

[coolVariable]

Haven't watched the show but I assume that rule (about travelling only back to a time where there is a time machine) is based on some physics theories for building a time machine:
when something moves fast, time goes more slowly.
If you create a bridge for instant (faster than light) communication or instant travel (which is possible e.g. with tangled photons), and then one end remains on "stationary" while the other is accelerated to great speed ... communicating/traveling between the two would be time travel/communications across time because of the time differential at the two end points.

 

[BriGy86]

Keep in mind we are already able to see back in time in a sense. Just about all of the galaxies and far off objects in space are being seen as they were millions if not billions of years ago since that is how long it took the light to reach earth.

 

[Rubycon]

Originally posted by: BriGy86
Keep in mind we are already able to see back in time in a sense. Just about all of the galaxies and far off objects in space are being seen as they were millions if not billions of years ago since that is how long it took the light to reach earth.

Right and if one left the planet fast enough they'd be able to pick up broadcasts from past events. example The conversion (due to red shift) as well as sensitivity would be the greatest challenge.

Being at the same place AND past time is the big challenge.

 

[destrekor]

Originally posted by: Rubycon

Originally posted by: BriGy86
Keep in mind we are already able to see back in time in a sense. Just about all of the galaxies and far off objects in space are being seen as they were millions if not billions of years ago since that is how long it took the light to reach earth.

Right and if one left the planet fast enough they'd be able to pick up broadcasts from past events. example The conversion (due to red shift) as well as sensitivity would be the greatest challenge.

Being at the same place AND past time is the big challenge.

In this concept, one could watch history as it was happening, but could not be there to fully experience it, let alone live it or try and change it, eh? Jet off far off into space FTL, and carry a super crazy telescope that can be pointed at Earth once you are at your desired distance/red-shifted time line, one that can go close enough to see the events happening on the ground.
Of course, that pesky cloud cover would prove to be an issue.

Actually... hmm, is that even possible, at least through theory (let alone the requirements of FTL and crazy powerful telescope). Could one, if given these gifts, be able to see the past happening on the ground? Since the Earth bounces light off, but also absorbs light, what light would one be able to see out in space from far away?
Or is that the sensitivity issue you mentioned? The telescope, I'd imagine, would have to be able to pick up the very little light that bounces off of humans, or whatever, at that kind of distance, right?

 

[Rubycon]

Conversion would be a cinch once you conquered traveling at superlight speed.

 

[GuitarDaddy]

Time travel and warp speed are nice to theorize about but both are nothing more than a twist of reason always to remain in the theoretical world.

Warp speed for example, what method of propulsion could possible propel you faster than the purest form of energy (light)? Not holding my breath for a proof of theory taceon drive

 

[aldarius]

Originally posted by: jandlecack

Originally posted by: spikespiegal

The reason for time is to keep everything from happening at once.

:thumbsup:

With all due respect to egghead physics crowd, I persist that time is a human concept.

I agree. What in our minds exists as time, years, fractions of seconds, changes "over time", progression, ageing and so on, is simply the way that the universe operates on a grand scale. It's just been inserted into our minds that there is something such as "time" which defines when what took place, and in theory leads to concepts like time travelling in the first place.

That's why I'm willing to say there will never be something like what we understand under "time travelling". It goes against the flow of the universe (in that...its flow is not up to us or any machine to manipulate). If at any point we'd witness something modifying the universe to this extent I'd say we'd have bigger issues than travelling through "time".

Not to bring religion in, but this triggers me to remember what my friend once told me about how God sees time. In that He is not control by it, but everythings is happening " at the same time" , that he sees the past and also the future together!( the confict between predestine and freewill)

Somehow i think that time travel is something like that, just more cubbersome in that we need to travel...

But if we can change the way we look at time, our life, and if we could come out with something apart from time to guage the action past, than we may unlock the secret behind this whole thing...

 

[Matt1970]

I guess I have to go with the linear notion. We will never be able to go back in time. It is however proven that time can be manipulated by speed. Put a clock on a plane and one on the ground. Go around the earth one time and the clocks will differ. But that is still time moving forward.

 

[brblx]

time travel is either impossible or will not occur before we are extinct, as evidenced by the fact that we've yet to have a documented time traveler from the future.

this is all i need to know.

edit-

Originally posted by: Matt1970
I guess I have to go with the linear notion. We will never be able to go back in time. It is however proven that time can be manipulated by speed. Put a clock on a plane and one on the ground. Go around the earth one time and the clocks will differ. But that is still time moving forward.

this, too. we know that time can be manipulated as it is passing, but to actually go back to past events has always been a pretty absurb notion to me.

 

[VinylxScratches]

I still don't understand how you can go back in time. I can see going forward into the future but back doesn't make any sense even if it's mathematically possible.

 

[destrekor]

Originally posted by: VinylxScratches
I still don't understand how you can go back in time. I can see going forward into the future but back doesn't make any sense even if it's mathematically possible.

Well, time travel as a concept is ridiculously confusing, and since there is no guaranteed proof of it being possible or not, that just further muddies all the theories existing.

And since a lot of scientists simply go with the default "it's not possible", makes it harder to nail down a concrete theory.

I'd say it won't ever make sense until a unified theory is established. And then the astrophysics and math geniuses go to work, which will provide more to make sense of.

I'd say going one direction in time is just as confusing as going the other direction. Going into the near future is believable, but in essence you're just skipping time, and there is no way to return so you can experience the time skipped, so it's just like taking a nap and catching up with the world as it has continued without you.

Going into the far future, and returning, that's just as mind-numbing as going back in time to see what has already taken place.

 

[Nathelion]

Well, how about looking at it this way. This is all speculatory and has no basis in reality, but as a thought experiment I find it interesting. If we assume that we CAN go back in time, perhaps any time travel that will result in that said time travel not taking place simply will simply cancel itself out. So if I go back and kill my grandfather, then I would never have gone back and killed my grandfather, hence I never will go back and kill my grandfather. So even though I in a sense have the capability to step into my time machine and kill my grandfather, I never will. I could possibly go back and kill my friend Tom's grandfather... but of course, if I never knew Tom, why would I have gone back to kill his grandfather? To look at it from a multiverse point of view, maybe it is not possible for a universe to "branch" when one of the branches will lead to a time travel event and an associated time paradox. Only the non-paradoxical branch would be allowed. Any act to, say, alter history would thus be problematic - if you went back and killed Hitler in 1920, then you would never have had reason to go back and kill Hitler in the first place, now would you? You could still go back and be a pure observer of events, or you could interfere in a non-goal-based way, at least in a minor sense - if I go back and take a dump on someone's porch in 1980, that would be unlikely to have repercussions wide enough to cause a paradox. If I kill a random guy in the street in 1990, that is unlikely to cause me to change my mind about killing a random guy in the street in 1990. Since the ramifications of a change in the timeline grow as time passes, it is conceivable that longer jumps would be less likely to be "successful" (a failure would, of course, never happen in the first place). Killing a random hunter in the stone ages is much more likely to cause widespread changes today than killing a random guy off the street in 1990. Perhaps successful (interfering) time travel is exceedingly rare, indeed so rare that it has never happened in our time in our reality, or has interfered in such a minor way as to go unnoticed.

In the non-multiverse view of things, one could view the "path" reality takes akin to minimizing an energy function - some of the most "desirable" paths for the universe to take may contain paradoxes, and are therefore disallowed. The universe will instead take a slightly less desirable path that does not contain paradoxes, but may well contain time travel.
This idea could be extended to other phenomena that would cause paradoxes - supra-light-speed travel anyone? While traveling from point A to point B could cause time paradoxes, any chain of event that actually does lead to a time paradox is disallowed.

Of course, as a physical theory the entire preceding two paragraphs suck, since they carry (almost) no predictive power. Nevertheless, I find it to be an amusing thought experiment.

 

[aldarius]

Time travel may already be possible in the future.

Example, someone in the future goes back and kill Minx ( just make this name up), to prevent the second world war, but because history have to happen, Hitler rise and second world war came.

Just like if Judah didnt betray Jesus, than someone from the 12 will surely betray Him, because it have to happen.


So its like trying to stop something that's inevitable, in the video it shows that something will happen to cause you to fail in your mission to kill your grandfather if you travel back.

Or if you successfully kill your friend grandfather, by coming back, you may have lost all the memory you have of ever having meet this friend!

Maybe because the people in future sees that time travel in fact dosen't change anything, they just simply destroy the machine and live on....

 

[jandlecack]

Originally posted by: aldarius
Time travel may already be possible in the future.

Example, someone in the future goes back and kill Minx ( just make this name up), to prevent the second world war, but because history have to happen, Hitler rise and second world war came.

Just like if Judah didnt betray Jesus, than someone from the 12 will surely betray Him, because it have to happen.


So its like trying to stop something that's inevitable, in the video it shows that something will happen to cause you to fail in your mission to kill your grandfather if you travel back.

Or if you successfully kill your friend grandfather, by coming back, you may have lost all the memory you have of ever having meet this friend!

Maybe because the people in future sees that time travel in fact dosen't change anything, they just simply destroy the machine and live on....

I think the concept that I find more believable than yours is that everytime someone may have gone back in time from the distant future and changed something, he created another reality, another flow of time that runs parallel to the one we currently live in and thus not change anything about *this* stream. Not to say you are wrong obviously. No knowing that.