Why isn't time travell possible?

[rc5]

The only argument I saw is that you can't change past.

People seem thinking only past can determine current and current determine future. What if future can affect past as well?
Imagining facing two mirrors to each other, a portion of the light emitting from the first mirror gets reflected back by the second mirror, and a portion of the light projected to the first mirror is reflected back again, and so on.

 

[Chaotic42]

Well, reverse time travel would require an decrease in entropy.

 

[PrinceofWands]

You can, at least going forward. Either through acceleration or gravity (same thing) you can reduce your time to a very small portion of that of others...hence, hovering over the event horizon of a black hole or travelling near c, you would experience 1 minute for every 1000 (or any number really) of us. Stay as long as you like, then come back to us 1000 years later.

Regression into the past is an entirely different concept however (which is unfortunate as I REALLY want to see about 12000 years ago).

 

[Chaotic42]

Now that I have a little more time....

Entropy is the growing of the disorder in a system. Things go from a higher level of order to a lower level. For example, if you take a box with 3 blue, 3 red, and 3 white marbles, formed into a square and shake the box, the marbles will become unorganized (example used by a teacher).

Time travel into the future is possible, as we are doing it constantly. As PrinceofWands said, the closer an object gets to c, which is the speed of light, a constant, the faster time seems to pass for that object. It's mass increases, so it takes more energy to push it. It's impossible for anything with mass to travel at c, so you could say that the factor of increase in the passing of time for any given object is a function of speed, and has a limit of infinity as speed approaches c.

You should check out 'A Brief History of Time' by Stephen Hawking.

I'm not a physicist (yet, it's what I'm going to go to school for), so I hope I got everything right.

Chris

 

[PrinceofWands]

'The Elegant Universe' is an awesome book as well. Can't remember the author offhand, and it deals more with superstring than time directly, but it's an increadible read for those without advanced physics training.

 

[Maggotry]

<< 'The Elegant Universe' is an awesome book as well. Can't remember the author offhand, and it deals more with superstring than time directly, but it's an increadible read for those without advanced physics training. >>


Brian Greene is the author
Another good read for beginners is The Whole Shebang by Tim Ferris

 

[PrinceofWands]

That's the dude! Thanks...too tired to look it up online.

 

[Jimbo]

Why isn't time travell possible?
Who says it is not possible. Except for a few Nobel scientists types.
If you can think of the idea someone somewhere will figure out how to do it. Look how long it took human flight to happen. Time travel, foreward or backward or whatever, I'm sure can be done, it is just a question of how soon we can figure out how to do it.

 

[db]

To travel into the future, there must already be a today that is in the past. Tomorrow must have already happened. This suggests that time is not a place behind or foreward, but existing at the same time, but in different "awarenesses". Physical travel may be one way to get there; but I think there are non-"physical" (movement of mass) ways.

 

[911paramedic]

<< You can, at least going forward. Either through acceleration or gravity (same thing) you can reduce your time to a very small portion of that of others...hence, hovering over the event horizon of a black hole or travelling near c, you would experience 1 minute for every 1000 (or any number really) of us. Stay as long as you like, then come back to us 1000 years later. >>



This is how I look at it as well. I have read all the great books, brief history of time, einsteins universe, great feuds in science, relativity, etc.

The time travel debate is right up there with religion, you see it one way or the other. I believe that the above quote to be accurate but not so much a "time travel" situation. It is more a difference in relativity. You (the traveller) see time go by at a different rate than the others (on earth) do. You are not so much travelling in time, as you are experiencing time go by at a slower rate.

Clear as mud, right?

 

[ShotgunSteven]

Well, all the current arguments aside, as well as Dr. Kaku's estimated power requirments, etc., I think we may achieve time travel someday, if we do not wipe ourselves out. We will know when we create a successful method for travelling backwards in time as we would begin getting swarmed with time travellers from the future that was spawned from that present.

 

[Pocatello]

Not time travel, but looking at photographs that were taken by the Hubble telescope and see stuffs billions of years ago is mind boggling. Perhaps we can go back to the past, put somone else out there could be looking at our planet forming a few billions years ago from far away.

 

[911paramedic]

<< Not time travel, but looking at photographs that were taken by the Hubble telescope and see stuffs billions of years ago is mind boggling. Perhaps we can go back to the past, put somone else out there could be looking at our planet forming a few billions years ago from far away. >>



Pretty much what I was eluding to, time is relative. We see other planets past if we look at them, even though they are in the present from their view. Two different times occuring simultaneously. :Q

My brain is starting to hurt, too early for this topic.

 

[mastaki11a]

What would happen if you went into the past, and tried to kill your mom. It wouldn't be possible because if you killed her, she never would have had a kid who went into the past and tried to kill her! ADSAFs

 

[GermyBoy]

That'd be parallel universes. However, none of you are smart enough to discuss time travel, so I suggest we stop all future discussions now.

By the way, rc5, travel is spelled T-R-A-V-E-L. PM me and I'll take you back to your childhood and you can win that spelling bee.

 

[FelixDeCat]

NATTR.

 

[Dark4ng3l]

Yeah basicaly in paralel universes there would be a new universe cretaed for every single possible divergence in the possibility's in the universe for every single piece of existance at every single moment, witch would make an infinite number of universes.

 

[YOyoYOhowsDAjello]

Duh, you need a flux capacitor.

 

[fatbaby]

<< Duh, you need a flux capacitor. >>



Dude you need How to build a time machine

Build a time machine? Sure, but first you have to construct a wormhole. And not just any wormhole, but an hourglass-shaped one with a neck wide enough to accommodate human girth and without gravity-crushing forces. (After all, you want to survive the trip.) And while you can travel into the future you can only go backward in time as far as the date the wormhole was built-no ecotourism in the dinosaur age, please. How-to? What you need is: (1) a collider of such magnetic megastrength that you can implode a quark-gluon bubble and create a teensy wormhole to warp spacetime; (2) an inflator to enlarge the hole (the trick here is to inject negative energy in the form of anti-gravity matter, maybe using a laser to "squeeze" light); and (3) a differentiator to create a time difference between entry and exit holes (one way is to use the twins paradox well known from relativity theory, then again apply the inflator to produce a human-accommodating wormhole). Of course, all this bizarreness is foil for Davies to wax eloquent on concepts he has covered in earlier works: general relativity, quantum mechanics, black holes, virtual matter (non-empty vacuums), parallel universes, as well as assorted time paradoxes. Here, he displays his usual glibness in a format gussied up with simple drawings and outline portrait sketches of the greats from Newton to Hawking. Indeed, one suspects a bit of not-so-cosmic book-inflation here. And there's a disclaimer. On the one hand, Davies proclaims that, yes, all this is theoretically possible; on the other, healludes to a theory called chronology protection in which all of the above is taboo. Davies Lite, with much sleight of hand.

 

[PsychoAndy]

<< Duh, you need a flux capacitor. >>

And a Mr. Fusion.
This is mind boggling. Damn einstein and his relativity theory...

 

[UberDave]

"Pretty much what I was eluding to, time is relative. We see other planets past if we look at them, even though they are in the present from their view. Two different times occuring simultaneously."


Well, that's not really time travel to me, it's like a delay. The reflections of light just take longer to get here the father out you go... so in essence, you're seeing something that doesn't exsist anymore.

 

[911paramedic]

<<

<< Duh, you need a flux capacitor. >>

And a Mr. Fusion.
This is mind boggling. Damn einstein and his relativity theory... >>



This should get you up to speed to make the trip: Linky

 

[pallander]

>That'd be parallel universes. However, none of you are smart enough to discuss time travel, so I suggest we stop all future discussions now.>><
But you are smart?You must be a fool saying that...

 

[Yzzim]

<< Duh, you need a flux capacitor. >>



No Problem

Now all we need is a little Plutonium. Anyone know any Lybian nationalists? I've got some pinball machine parts...

 

[HombrePequeno]

<< That'd be parallel universes. However, none of you are smart enough to discuss time travel, so I suggest we stop all future discussions now. >>



Let's all apologize to Mr. High and Mighty here for having a discussion.

Why isn't time travel possible? Like someone said if you went back in time and killed your parents, that would present a problem. Now there are a few scientists that say that you would travel into a parallel universe and it wouldn't really affect you. I personally think that's a bunch of BS though.