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534 comments

I would... (0, Flamebait)

egg troll (515396) | more than 11 years ago | (#4134095)

Go back in time and whack RMS. This way the whole GPL software would never be around to infect legitimate companies. You know you agree with me, too!

I would... (2, Funny)

Anonymous Coward | more than 11 years ago | (#4134109)

Go back in time and stop CmdrTaco from starting Slashdot. This way the trolls would never be around to make asinine comments like the parent. You know you agree with me, too!

I would... (0)

Anonymous Coward | more than 11 years ago | (#4134183)

...go back and tell your mother that the sperm seepage from her ass after a serious ass banging can indeed make her pregnant if she's not careful during "cleanup", and the feces/ecoli infected sperm would likely lead to an offspring like you.

did i get first post? (0)

Anonymous Coward | more than 11 years ago | (#4134097)

first one?

Re:did i get first post? (5, Funny)

GutBomb (541585) | more than 11 years ago | (#4134245)

did i get first post?

no, but perhaps someday you can go back in time and get it.

propz (0)

Anonymous Coward | more than 11 years ago | (#4134098)

To all my dead homies. fp too.

Oh, btw, your link is broken, learn to fucking code Taco.

Build a time machine!!! (0)

Anonymous Coward | more than 11 years ago | (#4134100)

Yeah, I wish they had a time machine so I could go back and get first post!

Forget about it (0)

Anonymous Coward | more than 11 years ago | (#4134103)

It won't happen in our lifetime.

Oh wait...

Interesting Stuff.... (3, Funny)

echucker (570962) | more than 11 years ago | (#4134104)

I move we call for a slashback in a few hundred years when this might be possible. ;-)

Re:Interesting Stuff.... (2)

gilroy (155262) | more than 11 years ago | (#4134123)

Blockquoth the poster:

I move we call for a slashback in a few hundred years when this might be possible. ;-)

I move we call for a slashback a few years ago... :)

Possible? (0)

Anonymous Coward | more than 11 years ago | (#4134105)

#1? Maybe...Likely not

Speed up things.... (5, Funny)

Duckz (147715) | more than 11 years ago | (#4134106)

Wouldn't the best way to speed up things for this be to leave a post-it note stuck in the files saying "when this is finally invented, please travel back to August 24, 2002AD and provide the HOW-TO."
--
Todd

The point you're missing is... (1)

BoomerSooner (308737) | more than 11 years ago | (#4134126)

This only works for going forward, not backward in time. Going forward is easy (as the article says when you're on a jet) going backward is the hard part (and in all likelihood impossible for us).

Re:The point you're missing is... (1)

Orthanc_duo (452395) | more than 11 years ago | (#4134153)

Read the article. WIth the help of a worm hole travel to the past is theoretically possible.

I'm going to travel back in time and steal somones post to get
*pinky to mouth... evil laugh*
1 million karma

Re:Speed up things.... (1)

BabyDave (575083) | more than 11 years ago | (#4134143)

You probably couldn't do it - many (most?) theories of time travel contain the limitation that "the earliest point you could go back to is the point when the time machine was first switched on."

But then, I know bugger all about General Relativity, so I could easily be wrong.

Re:Speed up things.... (2, Interesting)

AvitarX (172628) | more than 11 years ago | (#4134197)

The universe is a very very big place. That in mind, who is to say there is not a stable wormhole next to a nuetron star that is million's of years old?

Or that there is some other life that has one that was created to million years ago?

There is no reason to assume that it is impossible to go back in time from now just because it is impossible for use to create the device.

Imagine if a small one of these was available like a 24 hour one. How much would your time be worth? You could literaly work a full shift, eat and sleep, go through repeat. Get a month or so of work done in essentially no time, but then you go home and you lost a month of your lifespan and are aged. The rest of your familly still unaged.

Even at no pay increase you could save money real fast and buy a house or something. spend a year or two in this thing spending $20 dollors a day in expenses. Go home with thousands of hours clocked. Everyone wins, the company gets years of somebodies work done in a day, you never nead to work again.

Re:Speed up things.... (2)

barawn (25691) | more than 11 years ago | (#4134211)

Nope - that wouldn't work. "You" are not unique and indivisible, especially with a time machine.

Man works full day (day 1).
Man goes through time machine to go back to beginning of day 1.
Man realizes that Man is already at day 1. There are now two of Man at beginning of day 1.
If Man wishes to go back through wormhole to repeat day 1 again (a third time), both Man (copy 2) and Man (copy 1) would have to go through.

etc. Step and repeat.

Anyway. Time machines like this are bull - it won't work, it won't happen. Blah.

Re:Speed up things.... (2)

barawn (25691) | more than 11 years ago | (#4134198)

This doesn't matter : being able to go back to the past at all still does nasty things like provide information from nowhere. Assume you've got a time machine running, and you state "OK, when I become rich, I will come back through my time machine and tell myself how I did it!" poof, you do it, become rich, all happiness prevails.

This is a closed timelike loop. In GR, bizarrely enough, this appears to be allowed. Then again, another example of a closed timelike loop is a flying winged monkey popping out of one side of the wormhole, laughing at the people there, and then going back through the other side.

You can guess how much I believe this stuff. :)

Re:Speed up things.... (2)

NoMoreNicksLeft (516230) | more than 11 years ago | (#4134237)

That sounds so dumb. Information from nowhere?

What if I randomly select a sequence from Pi, put it in binary, and discover that it is a complete online newspaper from 2012, complete with grainy black and white photos of Dubya in a black party dress?

And suppose 10 years from now, it happens like that. Big if, I know. But was the information provided from nowhere, just like you're complaining about?

Re:Speed up things.... (2)

barawn (25691) | more than 11 years ago | (#4134255)

"Information from nowhere" is identical to saying either a violation of conservation of energy, or at the very least, breaking the second law of thermodynamics.

In any case, the statement that you gave is an example of coincidence - you don't KNOW that the newspaper is real, so there's no real (valid) information there, whereas the example I gave (teach someone how to become rich) is an example where you DO know that the newspaper is real, so it is valid information.

It's the difference between going to a psychic and believing she's telling the truth and knowing (and being able to rigorously prove) she's telling the truth.

The first exists all the time: the second does not.

Re:Speed up things.... (1)

KoolyM (602345) | more than 11 years ago | (#4134257)

How does that work? If time travel would really be possible, why would there be an arbitrary limit to what point in time you could go back to?

Slashdot converts to .net (0, Troll)

pigeon (909) | more than 11 years ago | (#4134107)

It ain't easy, but not impossible. Heck, there are gazillion things that are not easy but not impossible, doesn't mean it'll happen anytime soon.

Re:Slashdot converts to .net (2)

agdv (457752) | more than 11 years ago | (#4134113)

Well, I think it may happen in just 7 months and a few days. In April the 1st of 2003 is the expected deployment date, to be exact.

Canceling moderation (2)

inio (26835) | more than 11 years ago | (#4134121)

This post made to eliminate an accidental bad moderation on the parent. please ignore.

Re:Canceling moderation (0)

Anonymous Coward | more than 11 years ago | (#4134195)

you know if you post anonymously, it'll still remove your moderation.

Farscape (1)

T-Kir (597145) | more than 11 years ago | (#4134108)

After watching the mid-season finale on Sci-Fi last night, with all the time travel, paradoxes, unrealized realities, and wormholes... it gave me a bit of a headache :-(

Worthy research (1)

wmspringer (569211) | more than 11 years ago | (#4134114)

It's nice that serious scientists are willing to spend time researching things that have very little chance of actually working. Who knows what new insights will come out of this..

Of course, the science fiction possibilities are really nice, too...anybody have a favorite time travel story to share? ;-)

Re:Worthy research (2)

Daniel Dvorkin (106857) | more than 11 years ago | (#4134144)

It's nice that serious scientists are willing to spend time researching things that have very little chance of actually working. Who knows what new insights will come out of this..
Yes, like semiconductors. They have very little chance of actually working. Why aren't those serious scientists spending time on more important things, like vacuum tubes? Oh, well, maybe some theoretical insight will come out of it, but nothing useful. Certainly not in my lifetime.

Hmm (2, Funny)

KanSer (558891) | more than 11 years ago | (#4134120)

As long as you pay the toll...

"Somebody's gotta go back and get a shitload of dimes!"

Possible? maybe. (1)

Hex4def6 (538820) | more than 11 years ago | (#4134124)

I think that it should be possible to travel forwards in time - heck, get close to a black hole, and time should fly :)

but backwards will never be achieved. It presents a unique paradox; Once you travel past the instant you started, will you stop?

Re:Possible? maybe. (1)

russianspy (523929) | more than 11 years ago | (#4134142)

Travel forward in time. Dude, you're allready are doing this. If you're talking about affecting the speed of your passage through time - well.. just get on a very fast ship - Einstein has been there ages ago.

Paradox and Causal Loops (5, Interesting)

bravehamster (44836) | more than 11 years ago | (#4134125)

Am I the only one who really wants to see what happens if the universe encountered a true paradox? Would the universe cease to exist? If we assume there are other intelligent species out there (which, given the size of the universe, I'm gonna say is almost a definite), then if time travel is possible then most likely some other species has already invented it, created some sort of paradox, and the universe has continued on. So the whole "universe ceases to exist" thing doesn't seem very likely. Too bad. It would be kind of neat if the Ultimate Weapon was a time travel machine that killed the inventors grandmother.

Re:Paradox and Causal Loops (1)

micronix1 (590179) | more than 11 years ago | (#4134134)

every time a time machine is created, someone eventually goes back in time and makes sure that it's not invented. paradox that. haha.

Re:Paradox and Causal Loops (2)

dattaway (3088) | more than 11 years ago | (#4134248)

The only problem with a time machine is that the universe would have to allow recursive deminsions.

You can program recursive loops at the risk of being shot, but the universe simply doesn't have the logic to make it possible.

Re:Paradox and Causal Loops (1)

wmspringer (569211) | more than 11 years ago | (#4134138)

What if it was a localized paradox that stopped time only in that portion of the universe?

We could find that some galaxies no longer exist, or never did exist...although if they never existed, I have no idea how we would find them..

Re:Paradox and Causal Loops (1)

russianspy (523929) | more than 11 years ago | (#4134152)

>> If we assume there are other intelligent species out there

Other intelligent species? Have you found any on Earth?

Re:Paradox and Causal Loops (0)

Anonymous Coward | more than 11 years ago | (#4134215)

<sarcasm>Someone so witty like yourself is obviously intelligent. So I found at lease one.</sarcasm>

Re:Paradox and Causal Loops (0)

Anonymous Coward | more than 11 years ago | (#4134160)

There aren't any paradox if each time you travel through time, the universe splits in two: in one universe bravehamster enters a box and disappears, in the second universe bravehamster appears out of nowhere, kills her mother or whatever, it doesn't cause any paradox because it's a different universe.

Re:Paradox and Causal Loops (2)

barawn (25691) | more than 11 years ago | (#4134235)

Let me clear that up a bit for you: it wouldn't be a paradox if the Universe was already infinitely split and existing in all possibilities through all times.

"Each time you travel through time" implies that there's a "time" on top of "time", which doesn't work - same with "the universe splits in two". Once you're talking about a 4D universe (unified spacetime) the universe can't *do* anything. It just is.

Re:Paradox and Causal Loops (2)

barawn (25691) | more than 11 years ago | (#4134170)

Depends. The problem is that no one really has any good math for disjoint geometries (I'm surprised no one's tried with similar logic to Riemann surfaces, but hey) so it's a little hard to say. That being said though, there's no reason whatsoever to believe that a particle cares whether or not the worldline behind it goes to a consistent universe.

For instance, think of the Back to the Future scenario. OK, so we know immediately that the "your family is disappearing" bit is bull, since that superscribes an additional time on top of time. Marty only had so much "time" to restore "time"... yah... okay. Would it occur instantly? That would kindof imply that your body cares where it came from - that a break in the worldlines of the particles of your body would somehow "propagate forward" - even if it happened instantaneously, this doesn't make sense - it's another situation where you're describing a "time" on top of "time".

Bottom line: nah. My guess would be that it would be more like a Riemann surface thing: the action which breaks your past worldline would essentially move you to a different quantum universe. This would (of course) break conservation of energy. Then again, you also are talking about some mega-huge-time-travely-thingy, so I don't think things like "local universe/temporal conservation of energy" would really apply if that thing existed.

I don't buy time travel into the past. It's too easy to disprove: just state "when I figure out how to build a time machine, I'll come back to this moment and teach myself." The fact that it doesn't happen is pretty good empirical proof.

Re:Paradox and Causal Loops (1)

AvitarX (172628) | more than 11 years ago | (#4134234)

how does your statment disprove anything? the person who actually invents time travel would have to come back and tell you. I dont't think anyone alive now has it in them to invent time travel, so how would they tell themselves about it? Also if you read the article you would have noticed you cannot go back past the time the machine was actually created.

If I had a time machine I would have every first post in every article on slashdot. Take that you stinky trolls.

Re:Paradox and Causal Loops (3, Insightful)

guttentag (313541) | more than 11 years ago | (#4134217)

Am I the only one who really wants to see what happens if the universe encountered a true paradox?
Am I the only one who really doesn't want to see what happens if the universe encountered a true paradox? Let's not, and say we did.

There was a kid in my second-grade class who really wanted to see what would happen if he stuck a pair of scissors into an electrical outlet one day. The next day, our teacher told us he "moved."

One man said he didn't want to see what happens when you detonate an atomic bomb, and the people who ridiculed him for passing up a historic opportunity at the Trinity test site have long since died of cancer. At the time, they speculated that there was a possibility the bomb could ignite the atmosphere and kill everyone on the planet, but they went ahead with the test anyway.

It's always worth asking the questions, but it's not always worth the price of "let's see what happens."

Re:Paradox and Causal Loops (2, Interesting)

parad0x01 (549533) | more than 11 years ago | (#4134229)

Unfortunately there is no such thing as a true paradox. A paradox is merely a problem which exists within the confines of our own mental prejudices. Paradoxes are often created out of our own linguistics or malformed theories.

Re:Paradox and Causal Loops (0)

liloldme (593606) | more than 11 years ago | (#4134238)

Why is it that everytime people argue there must be other intelligent species in the universe, the almost always assume they must be vastly more advanced in technology compared to us: capable of travelling at light speed (or over) intergalactic travel and all that shit.

What if they're just as dumb as we are? Maybe they're even dumber?

It seems quite likely life exists somewhere else in the universe in addition to earth. But how do we know if intelligent life is common or not? How many species on our own planet do we consider 'intelligent'? Some would say just one. Seems like we have very little data on if intelligence is something that almost always develops when there is life or if it's just a fluke. And then what are the odds of that fluke occuring?

There's been some sort of life on this planet for how long -- two billion years? (I'm guessing). How many 'intelligent' species developed during that time? Is an intelligent life form a likely evolutionary path -- or is it unlikely? How do you define intelligence?

Re:Paradox and Causal Loops (1)

KoolyM (602345) | more than 11 years ago | (#4134247)

I'm not a physicist, but I always figured that the posibility for paradoxes was an indication that time travel was impossible. Not proof, not correllated (sp?) just an indication.

But maybe that's just me (I hate those star trek episodes that have to do with time travel as well).

black hole (0)

mass2k (599758) | more than 11 years ago | (#4134127)

"...if you fell into a black hole from nearby, in the brief interval it took you to reach the surface, all of eternity would pass by in the wider universe." that pretty fascinating...

Re:black hole (2)

barawn (25691) | more than 11 years ago | (#4134224)

It's actually just a perspective thing. It would take you a finite amount of time to cross the event horizon and reach the singularity - quite a very SHORT amount of time, actually, and kaboom. However, in order for the photons that left your body (your image, that is) to actually reach the wider universe, it would take forever (as you approached the horizon).

It's not like all of history would meet up with you in the brief interval before you hit the singularity: to the outside world, there would always be a distinct separation between you falling in and the person behind you falling in.

It's just like a black hole is a giant "slo-mo" video camera on the universe.

How About Flux Capacitor (0)

Anonymous Coward | more than 11 years ago | (#4134136)

I say go ahead with Flux Capacitor and go exactly 88 miles/hour.

Perhaps . . . but: (2, Interesting)

The FooMiester (466716) | more than 11 years ago | (#4134139)

I thought the reason that clocks ran faster in the attic than the basement was because of gravity's affect on the MECHANISM rather than gravity's affect on time. Likewise could be said about the atomic clocks. The clock is travelling thru quite a bit more space than it would if it were sitting, could subatomic particles affect it's function and accuracy?

Re:No. (1)

joshyc (584247) | more than 11 years ago | (#4134167)

You really need to real Einstein's General theory of relativity.

Re:No. (1)

The FooMiester (466716) | more than 11 years ago | (#4134201)

Nowhere does it say to disregard forces other than time that may change the measuring device. It's like saying that an arc welder speeds up time, because if I wear a wristwatch while welding, it'll run fast.

(For those who don't know, the magnetic field created by a welding lead in use will seriously mess with a quartz watch)

Re:Perhaps . . . but: (1, Redundant)

Crispin Cowan (20238) | more than 11 years ago | (#4134193)

I thought the reason that clocks ran faster in the attic than the basement was because of gravity's affect on the MECHANISM rather than gravity's affect on time.
Uh, no. You are precisely, exactly wrong. Clocks in the attic run faster than the basement because of gravity's effect on time, not on the mechanism.

Crispin
----
Crispin Cowan, Ph.D.
Chief Scientist, WireX Communications, Inc. [wirex.com]
Immunix: [immunix.org] Security Hardened Linux Distribution
Available for purchase [wirex.com]

Re:Perhaps . . . but: (5, Funny)

Robber Baron (112304) | more than 11 years ago | (#4134222)

Crispin
----
Crispin Cowan, Ph.D.
Chief Scientist, WireX Communications, Inc. [wirex.com]
Immunix: [immunix.org] Security Hardened Linux Distribution
Available for purchase [wirex.com]


Oooo! Everyone check out the big brain on Crispin!

Re:Perhaps . . . but: (1)

oskarfasth (187750) | more than 11 years ago | (#4134260)

could subatomic particles affect it's function and accuracy?
We are talking about atomic clocks here, mate. They measure the vibrations of single atoms, which is the closest we can come to true measurement of time. In fact, our units of time are defined as certain amounts of such vibrations. The guys who constructed the clocks were also fully aware of all particles that could possibly *affect* the mechanism (not taking into account the force-carrying particles of quantum physics, whose existence are not exactly confirmed I believe (IANAPhysicist tho)), and took that into account. And I find it hard to believe that only one clock would have been used at each position in these experiments, and if indeed cosmic noise would have had any affect as you propose then this would likely 1) not be universally distributed, and so would have been easily discovered, 2) If it were, then both positions I believe would likely have experienced more or less exactly the same interference, so it would not have made any difference anyway.

The effects have also been reproduced in other experiments if I am not mistaken. And of course, don't forget Occam's razor: Einstein's theories do give the easiest explanation (allthough perhaps not the most easily acceptable) to why this measured time dilation occurs.

Old news. (2, Funny)

jellomizer (103300) | more than 11 years ago | (#4134141)

This article was posted years ago.... Oh umm. Wait a minute. Never mind. I never saw this article before. Yea thats it. I never this article before. Realy I have never saw this article. Why are you looking at my third eye funny?

Reflection... (1)

[Rainer] (65672) | more than 11 years ago | (#4134145)


If there's a chance time travel might become a reality, how come nobody from the future has visited us yet?

Re:Reflection... (0)

Anonymous Coward | more than 11 years ago | (#4134163)

They have. I refer you to the overlooked documentary, Star Trek IV: The Voyage Home.

Re:Reflection... (1, Funny)

Anonymous Coward | more than 11 years ago | (#4134187)

Who in their right mind would WANT to come back to THIS time ????????

Then again . . . maybe the corporate powers of the future are already here - and setting up the laws that make them invincible . . . . .

Re:Reflection... (2)

thales (32660) | more than 11 years ago | (#4134203)

"If there's a chance time travel might become a reality, how come nobody from the future has visited us yet?"


Perhaps they are visiting us now. Perhaps the UFO's are Time Machines instead of Space Ships, and the ETs are what humans will evolve into.

Re:Reflection... (1)

DDX_2002 (592881) | more than 11 years ago | (#4134240)

Perhaps they are visiting us now. Perhaps the UFO's are Time Machines instead of Space Ships, and the ETs are what humans will evolve into.
The thing is, unless there's something really special about this time in history, one would expect that time travellers would appear throughout human history if it were possible for humans to time travel - people wouldn't be able to resist.

For a start, I would expect a lot of people to want to go back and see what exactly happened at Calvary when the local romans put a couple guys to death, and more importantly, over the three days following. And yes, I know Gore Vidal actually wrote a novel about that.

I'm using my time machine right now (0)

Anonymous Coward | more than 11 years ago | (#4134147)

Unfortunately, it only goes forward... and it operates at the speed of time. But, if you're still interested, here's how it works.
  1. Decide how far in the future you want to go. (Let's say 1 minute.)
  2. Wait the length of time you wish to go, in this case 1 minute.
  3. Voila! You are now the length of time you wanted to go, again in this case one minute, in the future. Congratulations!

Simple (5, Informative)

KarmaBitch (562896) | more than 11 years ago | (#4134148)

Quick lesson in physics for those that don't want to read the article...

Time travel. Possible? Yes. It happens relativly speaking every day.

When you get onto an airplane you slow down in time. To say this simply. The faster you go, the slower time moves around you. This was confirmed back in the 1970's using atomic clocks. Although this isn't exactly time travel it's called time dilation which is a product of the general theory of relativity.

A quick little reference for those not familar with Relativity is a set of lecture notes [uoregon.edu] from a basic astronomy class in U of Oregon.

For a little more in depth reading I'd look into buying The Large Scale Structure of Space-Time [amazon.com] by Stephen W. Hawking. Or for those that are sadistic you can read Quantum Field Theory in Curved Spacetime and Black Hole Thermodynamics [amazon.com]. That is a collection of lectures from the University of Chicago. Although good in a sense of understanding relativity it kinda takes a tagent into the debate about light being a particle or a wave argument.

Re:Simple (2, Interesting)

ergo98 (9391) | more than 11 years ago | (#4134220)

When you get onto an airplane you slow down in time. To say this simply. The faster you go, the slower time moves around you. This was confirmed back in the 1970's using atomic clocks. Although this isn't exactly time travel it's called time dilation which is a product of the general theory of relativity.

One thing I've never understood regarding this involves motion, and what is "absolute zero" in regards to motion. Right now, for instance, the Earth is spinning me around at 1,040mph. At the same time, the Earth is spinning around the sun at 67,000 mph. Our solar system is moving away from nearby stars at the speed of 45,000 mph. My point is that our primitive concept of "speed" is based around the premise of an "absolute zero", but as far as I can tell there is absolutely no way for us to know how fast we are currently moving: All measurements of speed are merely relative-> I drive my car at X speed relative to the surface of the Earth, etc. For all we know, as far as I know (and I'm not a physics buff), the known universe is sliding sideways at 100,000miles per second, and we're totally unaware because it's all relative.

The point of all of this is the correlation between time and speed seems simplified if it quantifies speed as an absolute metric when as far as I can determine there is no such things: There are only relative speeds.

Blah, I'm blabbering. There is a point in there somewhere.

Re:Simple (2)

micromoog (206608) | more than 11 years ago | (#4134256)

Everything you just said is precisely why the theory of relativity makes sense. Things move "relative" to other things. There is no "absolute zero" motion.

Motion is absolute only in relation to a specific frame of reference.

Huh? (0)

Anonymous Coward | more than 11 years ago | (#4134151)

Can a mod please explain to me why this pseudo-scientific crap gets it's own story,
and I can't even get this post [slashdot.org] modded above 0??!?

Re:Huh? (0)

Anonymous Coward | more than 11 years ago | (#4134168)

Because you sound like a loon?

Have you tried calling Art Bell [artbell.com]? I'm sure he'd love this idea.

Re:Huh? (1)

benp_85 (578318) | more than 11 years ago | (#4134236)

because you posted as an Anonymous Coward..!? Why would you do that? Now you won't even find this message, as it's not linked to your /. account. Silly you. -ben-

psychological ramifications (0)

Anonymous Coward | more than 11 years ago | (#4134155)

Time travel into the past, if achieved, will have a destructive impact on our notion of causality. Either that, or our romantic ideas about free will will fly out the window. Possibly both will be lost.

Either way, our entire understanding of self, universe, and the relationship therebetween will be radically changed.

it was nice knowing me. :)

Bah, theory (-1, Troll)

PhysicsGenius (565228) | more than 11 years ago | (#4134156)

As a physicist I have nothing but the utmost respect for mathematics...as a tool. Allowing ourselves to be mislead by some theoretical models is the height of foolishness, however. Making a prediction is fine, as long as it is followed up by a concrete experiment that demonstrates the math is sound. These guys are about 20 steps ahead of experiment, which makes them pretty much guaranteed wrong.

Not to be too discouraging, though, we have been messing with some closed, time-like loops in our own lab. The results have been...interesting. We've had a few particles (nothing bigger than a carbon molecule) disappear without any net gain in energy (which would be a violation of the 2nd Law) that we've been unable to explain and even one guy who claimed that one of our lost particles showed up in his bubble chamber the previous week.

Fortunately we are responsible scientists and won't breathe a word of this until we've rigorously tested it. And maybe not even then, because imagine the weapons possibilities of time travel.

Time Travel on the micro scale (1)

wmspringer (569211) | more than 11 years ago | (#4134169)

Suppose that time travel was possible, but only on a microscopic scale, such that it was impossible to send humans, or even small robots through time, but just enough so as to send information.

Hook up a computer to a time machine and let it do all its processing in the past. The information need not be detectable in the past (so it doesn't change anything, and doesn't give us a paradox) but it effectively allows the computer to solve almost any solvable problem instantly, as it can use billions of years for processing...and then use them again if it needs more time.

NP-completeness might not be meaningless (if it would take a trillion trillion years of processing time to solve a problem by brute force, it would still take a while doing it in billion year chunks) but if you could use 2 billion billion years every second, a lot of problems would become tractable :-)

Of course, how the processing during those billions of years will happen, since the computer stays where it is, is another question..

Time travel is fundamentally impossible (1, Interesting)

Anonymous Coward | more than 11 years ago | (#4134171)

Time travel is fundamentally impossible. One does not travel through time. One travels through space and time is how we measure this travel.

Remember, nothing moves in spacetime.

A simple way to think of it is this: Movement through space is represented as distance/time. How would one represent movement through time? It should be time/, but there is nothing to put in the denominator.

Time travel isn't possible without paradoxes (0)

Anonymous Coward | more than 11 years ago | (#4134172)

At least not two-way time travel.

Option 1: Going back in time
You travel away from earth faster than the speed of light. If faster than light travel is physically impossible, you go the opposite way the Earth is going at less than the speed of light. Either way, you catch up with light that left the Earth a long time ago. With a powerful enough telescope, you can observe what happened in the past, but can not in any way affect it. Affecting the past in any way would create a paradox.

Option 2: Going forward in time
Go near a neutron star, where time is warped by gravity. Sit there while time passes outside. You end up in the future, but there's no way to go back. Going back would again create paradoxes.

Some of the other articles in that issue of sciam discussed other things about time, like how some physicists see time as a fourth dimension, just like the spacial dimensions. This would mean that the 'present' has no special signifigance, and that all times exists all the time (if that makes any sense), just like all points in space exist. If this is correct, that would mean that the universe is constant, and does not change. Of course, that would also mean that nothing could be truly random, if the future already exists. Quantum mechanics seem to disprove this theory.

I think I've gotten off-topic here, so I'll just hit submit now.

What about Conservation of Mass??? (1)

tstoneman (589372) | more than 11 years ago | (#4134174)

The one thing that really foils time travel for me is that it completely and utterly violates the Law of Conservation of Mass/Energy. In a closed system, ie. the universe, all of a sudden you are introducing a new mass, ie. you, when you time travel, and thus are increasing the net mass in the system.

The only way around it that I can see is if you coordinate time travel to where mass is being converted to energy, and thus use that energy to recreate mass of a different type, like maybe in the middle of a nuclear explosion. But then, what's the point in time travel if you're just going to get irradiated, unless you

This would also mean that you would have to in advance know to conduct this experiment where mass is being converted into energy in the hopes that someone from the future would use it for time travel, which would then mean that you would instantly see the results of time travel.

If my theory is correct, then we should really be researching non-nuclear/radioactive ways of converting mass into energy, and then hoping that those people in the future will use this point in time to travel back by somehow harnessing that energy.

But in reality, I just can't believe that time travel can ever occur. Those time travel researchers are just like crop circle researchers to me....

Some Say it Has Already Happened ... (5, Interesting)

Crispin Cowan (20238) | more than 11 years ago | (#4134177)

If backward time travel is ever possible, then it has "already" happened. Someone has likely aleady travelled back before August 2002 and done something, we just don't know it.

Of course, this induces the potential for paradox, causing great cosmological and philosophical consternation. I don't know what will happen if/when someone goes backwards through time, but here's some ideas:

  • The universe forks in two when a paradox is induced.
  • The universe forks in two at the instant the traveller enters history (because at a micro-level, paradox is induced as soon as they appear).
  • Paradox induces a cascading feedback loop of self-modifying universes (each inducing a time-traveller who goes back and causes another chage) until the sequence halts with a universe in which time travel is not developed. My bet is that if time-travel is possible, then this is what has happened, because there is no evidence of time travel.
Forward time travel is of course possible right now, requiring only some patience :-) Accelerated time travel is also possible due to reletavistic effects and (possibly) cryogenics, allowing you to travel forward in time at some rate greater than 1 second per second.

Crispin
----
Crispin Cowan, Ph.D.
Chief Scientist, WireX Communications, Inc. [wirex.com]
Immunix: [immunix.org] Security Hardened Linux Distribution
Available for purchase [wirex.com]

Pretty basic argument (1)

Ligur (453963) | more than 11 years ago | (#4134180)

If it was possible to travel back in time, wouldn't we have encountered something from the future? I mean, eternety lies ahead, and *somebody* would've come to this exact place at this exact time sometime during eternity.
I mean, the possibility of it happening is endless and therefore a fact.

limits... (1)

ronaldcromwell (596642) | more than 11 years ago | (#4134189)

assuming that time slows down (relative to the observer) more and more as you approach the speed of light, and assuming that sometime in the future, we'll have the technology to go, say, 80% of that speed; what is the maximum realistic ratio of 'your time to their time?' any physics gurus care to share?

Never (0)

Anonymous Coward | more than 11 years ago | (#4134192)

*Humans* will never time travel. If it were to ever happen, so idiot would abuse it and we would have already seen the effects.
sorry

evidence that's it's impossible (2, Interesting)

klubber (218563) | more than 11 years ago | (#4134194)

Maybe this is dorky, but isn't the following evidence that time travel is impossible:

Since no person from the future has ever come back to say hello to us, wouldn't that imply that time travel will never be invented. Or else it will be invented, but our era in history was just too damn boring for people to come back to visit...

Re:evidence that's it's impossible (0)

Anonymous Coward | more than 11 years ago | (#4134243)

Simpler proof: I hate to be wrong. So if Time Travel is possible, the first thing I'd do with it is go back and stop myself from posting this. Or at least make myself post it anonymously.

modern time travel 'theory' (3, Interesting)

doubtless (267357) | more than 11 years ago | (#4134199)

is first outlined by physicist Kip Thorn and widely accepted by the scientific community as a real possibility. It is a method which utilise the ability of keeping worm holes open and high speed travel IIRC.

Black Holes and Time Warps: Einstein's Outragous Legacy by Kip Thorn is perhaps one of the best science books I read, though I didn't really read that many of them. :)

The twin paradox makes no sense to me (1)

wolftrap (603693) | more than 11 years ago | (#4134205)

Can someone explain to me how do you tell which twin ages more quickly if you can't tell which is actually moving closer to the speed of light? Isn't it possible that the Earth is moving through the universe at a high speed so the spaceship is really at rest, in which case woudn't the spaceship twin age more quickly?

Re:The twin paradox makes no sense to me (2)

Peaker (72084) | more than 11 years ago | (#4134242)

The Twin paradox is about one twin who accelerates and then slows down (while the other hasn't accelerated or changed his speed significantly) and meets the other twin. This is the source of the assymmetry and not the speed itself.

Travelling through time can't be possible. (2, Insightful)

Frobozz0 (247160) | more than 11 years ago | (#4134206)

I've given this some real thought and if it's possible to time travel at all, it would not be as how we see it in the movies. I'm a philosopher at heart and I think these points have been heard in many different forms:

  • If I could travel back in time, then why would we not have seen people doing so already? Wouldn't travelers from OUR future visit us now?
  • If it is at all possible, then it can't be possible to effect the future or the past-- you may only observe.
  • There are very strong arguements that TIME DOES NOT EXIST. Everything is relative to the observer, and many arguments have been made that suggest that Quantum reality is true-- that all possibilities in the universe are played out and live in discrete "strings" of reality. Sometimes, those strings cross, and you get phenomina such as Deja Vu. Take a lok at the following book: The End of Time, by Julian Barbour. Also, anything by Stephen Hawking.
  • The effects and observations we make concerning time travel may be directly influenced by our transendental means of observation. That is, how we perceive reality is completely based on how we observe it. Really take a second to think about that, because it's one of the most profound concepts I've come accross.

I just don't see it as a reality. I think what will actually happen is something altogether different-- but not a physical human being traveling into the past to hang out with Babe Ruth. Know whut I mean, vern?

Fun trick (5, Funny)

mother_superius (227373) | more than 11 years ago | (#4134208)

Wear weird clothes (not weird in the everyday weird people sense, but truly out of place). Walk up to someone (inventing an accent is fun) and ask them what year it is. When they say, puzzled, "2002", get a huge smile and dance a future dance away yelling "it worked, it worked!"

Fun to confuse people with.

Just as fun: Dress up like a hippie or something else interesting from the past and change everything accordingly to the past.

If I could Travel back in Time... (1)

cioxx (456323) | more than 11 years ago | (#4134210)

I would go to 1894 and stop the conception of a certain somebody named Gavrilo Princip. The man whos actions set off chain reactions to WW1 and beyond.

The man indirectly responsible for 80,000,000 deaths in 20th century alone. 80M. That's not a joke.

bio [ku.edu]

Sorry this is nothing scientific, but thought I would share that small fact which is overlooked in history books.

Re:If I could Travel back in Time... (0)

mass2k (599758) | more than 11 years ago | (#4134246)

indirectly, his mother is responsable..wait, his grandmother...wait, GOD

Assuming that time-travel is indeed possible... (1)

Elledan (582730) | more than 11 years ago | (#4134212)

Wouldn't this mean that it's possible to send matter from a certain 'time-frame' to another time-frame, thereby increasing the total amount of matter in the latter time-frame's universe (or parallel universe, if you wish), and reducing the total amount of energy in the former time-frame's universe?

Consequently we've created ourselves another paradox: if you travel back in time to a period where you already existed, there'll be two copies of you, of a different age (most likely, at least). Which one of these travels back into time, and won't there be already two copies waiting? And then three copies will be there in the same period, no?
So if one were to travel back into time, wouldn't that automatically cause this traveling back in time to be repeated ad nauseam?

The first thing we've to do is to completely dismiss the idea that time is merely linear.
Whatever we think time is or might be is precisely what it is not or can't be.

I don't think so... (0)

Anonymous Coward | more than 11 years ago | (#4134225)

I think it was Douglas Adams who said that once invented, time travel will simultaneously exist at all points in time.

This is what turned me off on time travel as a whole... It may be kept a secret for some period of time after it's invention, but one leak into the past and whamo, its everywhere.

If I had a time machine.... (0)

Anonymous Coward | more than 11 years ago | (#4134230)

I would go back in time a register slashdot.org

Maybe then, that site could be used for something useful...

Re:If I had a time machine.... (0)

Anonymous Coward | more than 11 years ago | (#4134251)

Maybe then, that site could be used for something useful...

Like porn!

Help (0)

Anonymous Coward | more than 11 years ago | (#4134231)

I am trapped in a prison of the mind.
If science can't measure or rationalise it, it cannot possibly exist.

If it is from the west it has to be true.
If it is from the east it has to be false.

If they told me that I only had to train my mind to see that time and space were an illusion, I would tell them that there must be a microscope that could prove it, or a machine that could replicate it.

I am trapped in a prison of the mind.

http://www.sivanandadlshq.org/messages/mind.htm

Whatever could happen, does happen... (2, Interesting)

Fulg0re- (119573) | more than 11 years ago | (#4134232)

There's another possibility that was not mentioned in the article, namely, the possibility of different quantum realities. Imagine for an instant, that whatever could happen, does in fact actually happen. Through what what called an Einstein-Rosen bridge (remember the TV show Sliders, the concept does have some scientific merit after all), different quantum realities can be bridged. So, if you go back in time and kill one of your parents, you would still exist because you entered a different reality, one amongst an infinite number of them. Paradox solved. QED.
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