The main reason is because time is not tangible; it's a derivative concept, and therefore you cannot travel through it any more than can you travel through the set of cardinal numbers.

Discuss.

That is why the time continuum is not to be fucked with...ever. This is where religion and science dont and do mesh. If people ceased to exist, what about their souls in heaven..would they autimatically be vangquished etc...even god, if there is one, doesnt want this to happen. Man will never be allowed to have the capabilities to go through time. Time is the ultimate chemistry

teller said:

Let's have an internet scavenger hunt...

Okay, people... look for information on Einstein-Rosen bridges and static property black holes.

it sounds impossible. has no logic for us, but hey, people thought once that the world was flat. laughed when you said one day a man will be on the moon, so who knows?
only time will tell

But then again, if people could travel through time, then we should've encoutered some people who come from the future, after inventing a machine like that.
Damn...you got me all confused now, I gotta rest for a while
[This message was edited Sat Nov 2 14:23:20 PST 2002 by Heavenly]

IceNine said:

Uh oh...did I just step into something over my head?

Well I'm a scientist, and I used to be a bit of an armchair cosmologist, astrophysicist and astronomer. So I'm pretty well read on the subject.

I can safely conclude that I don't know. And nor do any of you for that matter

teller said:

Start with a Black Hole ...

The physical possibility of time traveL is something of a catch-22. Any object that's surrounded by the twisted space-time that time travel requires must by its very nature be fantastically perilous, a maelstrom that would inevitably tear apart the foolhardy traveler. So physicists have labored to create a theoretically acceptable time machine that's free from nasty side effects like certain death. Their starting point: black holes.

Black holes are famous for sucking in everything around them—including light—and never letting go. But black holes have other characteristics, namely the way they bend nearby space-time. A black hole is infinitely dense, which means that it pulls the fabric of space-time to the breaking point—creating a deep pockmark, complete with a tiny rip at the bottom.

Many have wondered what lies on the other side of this rip. In 1935, Einstein and his colleague Nathan Rosen developed a scenario in which the tiny rip in a black hole could be connected to another tiny rip in another black hole, joining two disparate parts of space-time via a narrow channel, or throat. The Einstein-Rosen bridge, as the notion was then called, looks like a black hole attached to a mirror image of itself.

This bridge—a sort of back door leading from the interior of one black hole into another—is today known as a wormhole. Such a portal could in theory create a shortcut through space-time—just the thing a time traveler would need if he wanted to cheat Father Time out of a few million years.

Next, Modify the Wormhole ...

The problem with wormholes is that the channel created between two black holes is minuscule, smaller than the center of a single atom, and remains open for only a fraction of a second. Even light, the fastest entity in the universe, would not have enough time to pass through. And no matter how sturdy his spacecraft, our traveler would inevitably be ripped apart by the black hole's immense gravitational forces. Because of these and other problems, the Einstein-Rosen bridge was for many years thought of as a geometric curiosity, a theoretical quirk that could never be of use to even a fictional time traveler. Einstein's equations might allow for wormholes, but the universe certainly did not. All that changed in the 1980s, however, when a physicist at the California Institute of Technology devised a better way to use wormholes as time machines.

If Einstein and Rosen are the architects of the space-time shortcut, then Kip Thorne of Caltech is its structural engineer. Starting from the rough sketch that Einstein and Rosen left behind, Thorne created an algorithm that describes in strict mathematical terms the physics of a working time machine. Of course, actually building Thorne's time portal would require a technological prowess that is at least many centuries away. But his work proves that time travel is possible—at least in theory.

Thorne's problem was finding a way to hold open the wormhole's channel, or throat, long enough for an explorer to pass through. Ordinary matter won't do: No matter how strong it is, any scaffolding made of matter cannot brace against the crush of space-time. Thorne needed a substance that could counteract the squeeze of a black hole. Thorne needed antigravity.

Instead of contracting the space around it, as ordinary matter does, antigravity—or negative energy, as it is sometimes called—pushes it apart. In theory, antigravity would be placed inside a wormhole's throat, opening it wide enough for an astronaut, or possibly even a spaceship, to pass through. Antigravity does the trick; the problem is finding it. Einstein first postulated the existence of antigravity on cosmic scales in 1915, a conjecture proven correct eight decades later. But Einstein's antigravity is wispy and dilute, a spoonful of sugar dissolved in the Pacific Ocean. Opening a wormhole requires a regular torrent of antigravity.

The best current candidate for creating concentrated antigravity is called the Casimir effect. Because of the quirks of quantum mechanics, two flat metal plates held a hair's width apart generate a small amount of negative energy. That energy, multiplied many times over, could in principle be used to create a traversable wormhole. The widening, meanwhile, would dilute the strength of nearby gravity, preventing the traveler from being torn apart.

Once the antigravity scaffolding is holding open the portal, the traveler passing through would emerge in a distant place. But time travelers, of course, want to journey not just geographically but temporally. So Thorne's next step was to desynchronize the two regions on either side of the wormhole.

To do this, he applied an old trick of Einstein's. A major consequence of Einstein's Special Theory of Relativity is that time slows for objects that move quickly. Thorne applied this principle to one of the two black holes that make up a wormhole. Imagine lassoing one of the black holes—perhaps by trapping it inside a cage of negative energy—and towing it around the universe at close to the speed of light. That black hole, and therefore that end of the wormhole, would age more slowly than the stationary end of the wormhole. Over time, the black holes would become desynchronized, two objects connected through the wormhole but existing in different eras. An explorer who entered the stationary end of the wormhole would exit the moving end, many years earlier than when he departed, making the wormhole a true time portal.

Or Try It on a Shoestring

The most recent development in the physics of time travel came in 1991, when Princeton astrophysicist J. Richard Gott III suggested that hypothetical objects called cosmic strings might enable an astronaut to travel backward in time. Cosmic strings are long, thin objects that some cosmologists believe coalesced out of the universe's very earliest days. They are infinitely long, no wider than a single atom, and so dense that a few miles of a single cosmic string would outweigh Earth itself.

Gott's proposal relies on idealized versions of cosmic strings. In order to be em-ployed in the service of a time traveler, two cosmic strings, perfectly parallel and traveling at nearly the speed of light, must whiz past one another like two cars traveling in opposite directions on a highway. As the strings pass each other, space-time would become profoundly distorted by the influence of these fast-moving filaments. A savvy time traveler, waiting in a nearby spaceship, could exploit those distortions by flying around the coupled strings. If he timed it just right, the twists in space-time would enable him to return to his starting point before he began—making the voyage a one-way trip back in time. Which means that, according to the laws of physics, journeys through time are conceivable, if rather difficult to arrange. It may be only a matter of time.

IceNine said:

Theoretical stuff...no one has done any experiments on black holes, obviously...back to the original point then...is time an actual physical dimension, or a derivative concept?

teller said:

Time is not a "thing" like a physical object, it is a construct, but it is a necessary construct.

Time is not absolute as was stated by Newton and others, and there exists a possibility of negative time. Since Einstein's Theory of General Realitivity shows that space-time is curved around massive objects or objects with massive gravitational force, it is theoretically possible to travel backwards in time through a pair of black holes connected with an Einstein-Rosen bridge.

I will not go into Stephen Hawking's Thermodynamic Arrow theory, as I know that you don't like him.

IceNine said:

I'm skeptical of such claims...perhaps in theory a photon or something can be made to act such the measurements come out backwards, but Quantum reality was long believed to be statistical in nature before they realize that it was just the limitations placed on the measurement apparati...

Hehe...yeah fuck Hawking and his daydreaming!!!

teller said:

The best thing about time travel is that it might very well be inter-dimensional and as stated by Hawking and others, our laws of physics need not apply in other dimensions.

So, yes it is ALL 100% theoretical, but it is fun to think about. I am also particularly fascinated by string theory and high-amplitudes nodes in superstrings. Still theories, but fun to think about.

Almost all quantum physics is theoretical in nature, but all science starts as a theory.

I found it particularly interesting when researchers "teleported" light from one place to another. That was FUCKING AMAZING to me. I was also stunned when light was frozen in place and then set back in motion.

The solution to the EPR Paradox was a major milestone as well.

Who knows where physics is going to go as we move forward... time travel might very well be possible in the future... but there are MASSIVE problems with traveling backwards or forward in time.

Traveling forward in time would be a futile endeavor, unless all things exist always and the future is pre-determined. The future is determined by the interaction of all matter in the universe and traveling forward in time would require an absolute knowledge of all interaction and outcomes up until the time that you were traveling to, otherwise you would not be in a future that was relative to your past.

The very fact that we cannot know everything about all possible interactions, nor can we even predict all possible outcomes of simple interactions in quantum physics, I would say that time travel is not possible in the way that it is commonly imagined... in effect, we cannot travel forward and backward in time relative to our current position, as doing so would require absolute knowledge of all events and occurrences.

IceNine said:

I'm open to physics being different in different localities of the universe...



Yes it is! As much I like to tease people who think it's very linear, I love the topic when it comes up in fiction!



I'm not very familiar with this experiment...was it the photon that travelled, or just the information? Sounds fishy to me, but imagine a photon tunnelling internet! No more latency!


Anyhoo...I'm off to spend time with the family...thx for the quickie Ice!

All I know about time travel I learned from "Star Trek" movies and the "Back to the Future" trilogy (which I have pre-ordered), but I have to say that I am very impressed with IceNine after having read this thread.

lovemachine said:

Thank you very much!



I am a student of quantum physics and I have read WAY too much stuff on the subject. One of my most prized possessions is a hardcover boxed set of ALL of Feynman's lectures on physics!

This kind of topic is my absolute favorite!

IceNine said:

You know what this does to me and how I can listen to you talk about this for hours! Damn!


.
[This message was edited Sat Nov 2 16:26:39 PST 2002 by AzureStar]

IceNine said:

It's a good topic, but most of the literature out there on QED is really wrong-headed...a lot of math figured out on a lot of theory that turned out to be a waste of time...

I'm actually pissed about QED...I never liked the two slit experiment, and I especially disliked how any physics student who learned about Quantum theory suddenly thought that it meant you could say that the macro-world was totally statistical and irrational for some stupid reason...over and over I've seen students express glee and delight at the fact physics makes no sense! Imagine my relief when it was finally settled that it's waves, not wave-particle dualities!!!

Sigh...I hate this topic...I think it's abused...nothing against Icenine per se, just the atmosphere of the topic in general...does no one care about the truth?

IceNine said:

Done!

http://www.popsci.com/pop...98,00.html







damn stinkin' space-time edits.
[This message was edited Sat Nov 2 17:44:31 PST 2002 by 2the9s]

off topic:one of my favourite time travel story, Hawksbill Station by Robert Silverberg
from the amazon review "In the mid-21st century, time travel is used to send political prisoners to Hawksbill Station, a prison camp in the late Cambrian Era. When the latest arrival suspiciously deflects questions about his crimes and knowledge of 'Up Front', the inmates decide to find out his secret"

AzureStar said:

Baah I can do the same thing (well, almost...) in french! (it's better )
[This message was edited Sat Nov 2 21:27:49 PST 2002 by jnoel]

If someone ever came up with a way to go back in time it would be complete chaos. Everyone would be fighting for the opportunity. And once everyone has gone back and redone everything as they wanted, we would end up with just as many problems as we have now.

what would be great is a machine which allow to see the past
imagine: the dinosaures, Van Gogh etc
but I think that so we could see Jesus, Buddah, Mahomet in reality and that would be chaos for the believers, and therefore for the humanity...

jnoel said:

Unfortunately for you, she is in love with me and all that!

let her answer!
anyways, define the concept of "love"

Ice, I didn't tell you, I've made a dream 2 days ago... (you were in it), I will start a thread about it

jnoel said:

Yes, I love him very much! I am twitterpated!

My last attempt to seduce Azure Star: I've just written this for you honey :pathetic liar:, I'm sooo intelligent!
if you want I call ya, you'll hear my soft voice

"Click Here!


More...


Concerned about Hair Loss?
Click Here for more information.
Click Here!



[Close]


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Advanced Physics Made Simple
Special Relativity
Introduced by Albert Einstein in 1905, this theory was developed to explain the experiment of Michelson and Morley:
The Michelson Morley Experiment
Think of a baseball pitcher throwing a baseball at 50 mi/hr from the pitchers mound. Then the ball crosses homeplate at 50 mi/hr. Now suppose the pitcher stands in the back of a truck travelling at 50 mi/hr and throws the ball at 50 mi/hr. Then the ball will cross homeplate at 100 mi/hr. This is just natural.
In the late 19th century, Michelson and Morley designed an experiment that replaced the baseball with light, and the truck was replaced by the entire Earth. But what they found was not the obvious solution. They found that light travelled at a constant speed. If the pitcher shines a flashlight at the batter, it goes at the same speed as if the pitcher shines the flashlight from the back of a moving truck.



Minkowski Spacetime
Actually, Minkowski developed this approach to special relativity after Einstein, but it makes the physics simple. You may have heard that time is a dimension just like space. IT IS NOT LIKE SPACE. Lengths measured in space are positive, and they are always positive. Lengths measured in the time dimension are called IMAGINARY, which means that a given length, multiplied by itself, is always negative. ( Since time is a negative dimension and space is a positive dimension, it is possible to have a total length of zero - this is the case for light)

The results of this simple physical idea imply, after long mathematical proofs,

1. TIME DILATION - A person who moves through space experiences a shorter period of time. In other words, if you sit on Earth for one year while your friend travels to Pluto and back, then your friend will claim that only six months had passed. This is not an illusion, nor is it a fault in the mechanism of a clock, it is a real effect. One way to think of this is if you walk along a straight line between your house and your neighbours house, and your friend walks from your house to the grocery store two miles away, and then to your neighbours house, you both start and end your trips at the same places, but your friend has travelled four miles further.

2. LENGTH CONTRACTION - If a car moves past you, it will seem shorter than it actually is.

3. MASS INCREASE - A moving object weighs more than an object which isn't moving. It can be shown that if an object travels at the speed of light, it must either weigh nothing (which is only true for light) or it is infinitely heavy. This implies nothing can travel at the speed of light.

Tachyons

You have probably heard this term in science fiction books and movies without knowing exactly what it was. If you read the section on special relativity, you know that nothing can travel at the speed of light except for light itself. Obviously there are things which travel slower than the speed of light, because our entire world fits in the category. What about faster than light?

There is nothing in the theory of relativity which prevents an object from travelling faster than the speed of light, although such objects can never slow down to below the speed of light or they would violate special relativity. Any particle which travels faster than the speed of light is called a TACHYON. Such objects must obey certain rules:

1. The mass of a tachyon is imaginary. Recall that this means that if you multiply the mass by itself, the result is negative.

2. Tachyons go faster when they lose energy. I must admit I can't think of a case when a tachyon would lose energy, since a collision with normal matter is forbidden. "
[This message was edited Sat Nov 2 23:14:14 PST 2002 by jnoel]

jnoel: You have no chance, so give up the seduction attempts.

To quote Heather talking about me earlier in this post:

AzureStar said:

Move on to the next one down the bar, my friend.

:LOL:

I have always wondered why men have such a need to answer the mysteries of the universe when they cannot even deal with the mysteries of the own actions. The vastness of the universe itself says to me, and this is only my opinion, that the mystery of the universe cannot be solved, at least not by mankind at his current level of intelligence. Man cannot even face, accept and understand his own human mysteries, let alone the mysteries of the universe. It's a waste of time & money. And not only that, the urgent need of mankind to understand the universe by looking at it and building space stations is not worth the damage done to the ozone layer. But they don't care, they just want to know what's going on in space right now and fuck the consequences. Our children will deal with that problem later. Right now, the matter at hand is what's out there, we must solve the mysteries of the universe! But hey, this is only my opinion. But one thing is for sure and undisputable -- we can never get back time.


I'm reminded of the book "Contact" by Carl Sagan. It is one of may favorites. Has anyone here read it?

SweeTea said:

Are you saying that you prefer the Ahmish way of life? No electricity? No Internet? No cars? No digital watches? Science gave us these things!

teller said:

LOL... how did you come to that conclusion. What has these scientific discoveries have to do with answering the mysteries of the universe? They were all discovered on EARTH. By humans, the EARTH'S inhabitors in there own time.

But to answer your question. No electricity - no, I like doing it with a red light.

No Interenet? Well I could certainly live without it, but then, I kinda like you guys.

No cars? I lived the first 22 years of my life without one, I think I could survive my remaining years without it.

No digital watches? Definately I could survive with those hideous things. I could never figure out how to make the damn things stop beeping! And the military time thing, that's really annoying.