Can we travel through time?

[animeguy]

Fellas, what do you think, can we travell through time?
I think it is possible, but only in the future. We can travell by different means: one of them could be freezing and the other extremly high speed (speed of light OR faster). We currently can't use any of them. Here's why: If we are frozen the ice crystals would destroy our cells. We would need special ways of freezing. So, that option is executable, just not yet, but it might be soon.

The second one goes like this:

Time is a bent line, along which we move. Now, if we could travel in a staright line, that wold be time-travelling, right? So, how do we move through time in a straight line? I think that that is possible with great speed. But there are minor problems: How could we reach such high speed? If we could gather energy from black matter, we could probably reach such speed. But IF we could gather it from black matter. Another problem is such: if we would be able to travel through time like so, we could do it only in space. And we would go to completly other side of space.

So, what do YOU think?

[Kyuu]

If time travel is possible, then how come we haven't met any travelers from the future?

Knowing humans, someone would go into the past and actually interact with the point of time that they would travel.

Given the possiblity of paradoxes, some people would not care and mess around with things anyways for either their enjoyment or personal gains. That's human nature for you.

[animeguy]

True, true... But i didn't even mention travelling in the past. And i forgot to metione that by this theoryes it is only possible to travel in the future. Otherwise I totaly agree with you, but i do not think we COULD travel back in time.

[xa0]

Heh. I don't think Either is true. If we were to travel at Light speed, Our eyes would like pop out at the back of our head y'know? Like just think for a second about that one. Then there's Time. But...Still..I cant predict the future so you could be right,

Not saying you're wrong. But just saying the chances are very Slim about us ever travelling light speed or time.

[Shadow Fox]

OK OK IF time travel were possible just like in back to the futer it would be dissasterous to make contact with ANY one at ANY given time...and mabye in the next 7 thousand years time travle will be possible

[Diavle]

In my opinion no it is not possible. For two reasons:

1. Throughout humankind's history one entity that that has always been constant is time, it has always moved forwards.

2. You mention speed, is there such a thing as negative speed? No there is not. Also i have read somewhere (cannot recall where) is that if a human travels at the speed of light for a second or a minute (can't remember for sure) then he or she will age only that second or minute whereas the rest of the world would age about 20 years. This could to some extent be called time travel into the future but this cannot be applied to time travel into the past (which is the topic at hand).

[Kyuu]

Anyways...

The real answer right now is: "We don't know".

However, I'll rule out going into the past because there has been no record of anyone in anytime meeting someone from the future. Even if it did happen, no one knows about it.

[Lament]

Talk about travelling back in time to the past often runs into contradictions. For instance, here's a typical time-travel story...
It's 1970. Bill starts out poor, but he's very savvy in business, so he is able to amass a fortune and build a huge business empire. His cut-throat tactics make many of his competitors, like Scott, miserable. In 2000 Scott dies a broken man. Scott's sister Sally hates Bill because of this. She's a brilliant scientist, so she builds a time machine and uses it to travel back to 1970. Sally steps out of the time machine and encounters Bill on the way to make his first business deal. Then she kills him, before he ever becomes rich.
The way this story tells things, 1970 unfolds twice. The first time, Bill makes his deal and gets rich. The second time, Sally kills Bill and the deal never takes place.
If we think of 1970 as a particular moment in time: then that story doesn't really make sense. How can a particular moment in time first happen one way, and then happen again, a different way? That would require that at one time, 1970 is one way, but then at a later time 1970 is a different way. How could that be?
Topic: http://www.princeton.edu/~jimpryor/courses/intro/notes/timetravel.html

[Bardiel]

how do you know that time is a bent line? time cannot simply be given a shape.

also if someone were to travel to the future how would he get back?

[animeguy]

I agree with most of you, but you were talking about traveling in the past, whereas i thought 'bout traveling in the future! And you're eyes wouldn't pop 'cause we would travel in space (no graviti & stuff). And I agree with baradile, time does NOT have shape, but I used it for easier understanding.
:)

[Battlestar]

In my opinion no it is not possible. For two reasons:

1. Throughout humankind's history one entity that that has always been constant is time, it has always moved forwards.

2. You mention speed, is there such a thing as negative speed? No there is not. Also i have read somewhere (cannot recall where) is that if a human travels at the speed of light for a second or a minute (can't remember for sure) then he or she will age only that second or minute whereas the rest of the world would age about 20 years. This could to some extent be called time travel into the future but this cannot be applied to time travel into the past (which is the topic at hand).

You are reffering to the time dilation effect. The closer to c you get, the more time slows down within your craft. I guess you could call it time travel, on the same grounds as Cryogenic freezing.

Frankly, I don't think Time Travel is impossible. Time is just the 4th dimension, one higher. We simply need to acess it and travel along it as we do this one. There are theories that slingshooting around a Star or just ripping open a 4D rift should do it. There's also that "Wormhole through a solar flare" thing.

However, the reason for lack of visitations (as far as we know it) is likely there is some kind of non-historical interferince policy, as you can never predict what changes you might have on the timeline. But there may be future cultural observers among us, we'll just never know.

Say, for example, you went back in time, and decided to totally change the outcome of Pearl Harbor. Good thing, right? Save a bunch of people, all nice and dandy. Except you didn't anticipate all the possible changes. After comming out of PH without a scratch, do you really think the U.S. would have the same motivation to develop the Atomic Bomb before Hitler did? Save Pearl Harbor, and we could very well be living under Nazi rule.

It's just one example of why time travellers don't make themselves known. If they exist anyway . . .

[Sarah In The Shadows]

I doubt time travel is possible...I don't even give it a second thought...the fact is there's basically no way to, either way you'll probably end up dead or looking like a moron for trying...and besides why would you wanna? I say don't mess with nature, it isn't right.

[Battlestar]

I doubt time travel is possible...I don't even give it a second thought...the fact is there's basically no way to, either way you'll probably end up dead or looking like a moron for trying...and besides why would you wanna? I say don't mess with nature, it isn't right.

No confirmed way. They said the same thing about the Sound Barrier. And about countless other barriers. Like flight.

Until we determine EVERYTHING about the Universe, no one can say that Time Travel is impossible, because it has not been proven impossible. Until such a time, far out concepts like Time Travel and FTL remain "possible".

I would reccomend searching around for some research papers, you'll find the possibilities of Temporal Displacement quite encouraging.

[Xanaphia]

I don't think we can travel through time. As far as I know, time is a concept invented by man, like honor, and possibly morality, not a force or an energy, and therefore doesn't exist in a physical sense.

If time is an energy, then it would have to travel faster than light. Nothing with any mass known to man can travel at the speed of light because the energy needed to accelerate the mass that much, and the additional mass automatically added onto the origional mass to increase possible acceleration, simply is not possible to come by. We would have to move faster than time in order to reach the future, which is not exactley possible as I stated earlier. Only energy would be able to travel through time.

And if, by the tiny chance, matter can travel through time, It'd probably prove useless anyways.

And now I shall hide in shame after my attempt to sound smart.

[Battlestar]

I don't think we can travel through time. As far as I know, time is a concept invented by man, like honor, and possibly morality, not a force or an energy, and therefore doesn't exist in a physical sense.

If time is an energy, then it would have to travel faster than light. Nothing with any mass known to man can travel at the speed of light because the energy needed to accelerate the mass that much, and the additional mass automatically added onto the origional mass to increase possible acceleration, simply is not possible to come by. We would have to move faster than time in order to reach the future, which is not exactley possible as I stated earlier. Only energy would be able to travel through time.

And if, by the tiny chance, matter can travel through time, It'd probably prove useless anyways.

And now I shall hide in shame after my attempt to sound smart.

Time is not an energy or a concept. It is a dimension. Just like Length, Width, and Depth. It's not an abstract concept, it is a very real part of Einstienian and Witten physics.

[Xanaphia]

I don't think we can travel through time. As far as I know, time is a concept invented by man, like honor, and possibly morality, not a force or an energy, and therefore doesn't exist in a physical sense.

If time is an energy, then it would have to travel faster than light. Nothing with any mass known to man can travel at the speed of light because the energy needed to accelerate the mass that much, and the additional mass automatically added onto the origional mass to increase possible acceleration, simply is not possible to come by. We would have to move faster than time in order to reach the future, which is not exactley possible as I stated earlier. Only energy would be able to travel through time.

And if, by the tiny chance, matter can travel through time, It'd probably prove useless anyways.

And now I shall hide in shame after my attempt to sound smart.

Time is not an energy or a concept. It is a dimension. Just like Length, Width, and Depth. It's not an abstract concept, it is a very real part of Einstienian and Witten physics.
Like I said: my bad attempt to sound smart. Now I know I'm an idiot ^_^'.

Either way, I still don't see a benefit in time travel. Too many paradoxes to worry about, and not enough good things seem to come from it. We'd be better spending the money and time on something else.

[Battlestar]

I don't think we can travel through time. As far as I know, time is a concept invented by man, like honor, and possibly morality, not a force or an energy, and therefore doesn't exist in a physical sense.

If time is an energy, then it would have to travel faster than light. Nothing with any mass known to man can travel at the speed of light because the energy needed to accelerate the mass that much, and the additional mass automatically added onto the origional mass to increase possible acceleration, simply is not possible to come by. We would have to move faster than time in order to reach the future, which is not exactley possible as I stated earlier. Only energy would be able to travel through time.

And if, by the tiny chance, matter can travel through time, It'd probably prove useless anyways.

And now I shall hide in shame after my attempt to sound smart.

Time is not an energy or a concept. It is a dimension. Just like Length, Width, and Depth. It's not an abstract concept, it is a very real part of Einstienian and Witten physics.
Like I said: my bad attempt to sound smart. Now I know I'm an idiot ^_^'.

Either way, I still don't see a benefit in time travel. Too many paradoxes to worry about, and not enough good things seem to come from it. We'd be better spending the money and time on something else.

I agree, Time Travel is too dangerous to be used for anything other than Historical Study. Very careful study that is.

Still, there are more immediate projects at hand that need to be dealt with first.

[Maes Hughes]

Here's what I think, no one can travel through time, they can only go to an alternate dimension that seems like either the past\future\or whatever makes u think u just traveled through time...

Time Travel using lightspeed is not time travel, its just travel in a very fast speed...

[~Sephiroth~]

Fellas, what do you think, can we travell through time?
I think it is possible, but only in the future. We can travell by different means: one of them could be freezing and the other extremly high speed (speed of light OR faster). We currently can't use any of them. Here's why: If we are frozen the ice crystals would destroy our cells. We would need special ways of freezing. So, that option is executable, just not yet, but it might be soon.

The second one goes like this:

Time is a bent line, along which we move. Now, if we could travel in a staright line, that wold be time-travelling, right? So, how do we move through time in a straight line? I think that that is possible with great speed. But there are minor problems: How could we reach such high speed? If we could gather energy from black matter, we could probably reach such speed. But IF we could gather it from black matter. Another problem is such: if we would be able to travel through time like so, we could do it only in space. And we would go to completly other side of space.

So, what do YOU think?

It has never and will never be as simple as that. I don't even think you could comprehend the amount of "what if's" that would have to be taken into consideration.

I think it will be possible, but by NO means is it possible now...... At least not for humans.

[Beldizar]

Time travel is easy. You are doing it right now, one moment at a time, moving closer to the next moment and further from past moments. As for traveling through time at a different rate than other people, you can do that too, its just a bit tougher.

Here's the crash course.

Einstien: Einstien and his...Special (I think it was the special anway) Theory of Realitivity states that the speed of light is a constant for all observers. Therefor, a person standing at rest who shoots a laser beam and measures the speed it travels finds that the beam is moving at c. A person on a space ship moving half of the speed of light looks down at the first person and measures the speed of the laser, and he also measures it to be c. The funny thing is, he's moving at 1/2c so according to classical physics, he should have measured the beam to travel at either 1/2c (because he was moving in the same direction, just not as fast, thus making light appear to slow down) or at 1 and 1/2 c (because he was moving in the opposite direction and should see it move faster.) If that doen't make sense, think about cars. If I'm standing on the side of the road, cars seem to be going pretty fast, but if I'm in a car and someone passes me, it moves much slower in relation to myself. Or if I pass by a car going the other way it seems to be going much faster. That's the way everyone before Einstien thought light worked too. The fact is, both the person on the ground and the person in the ship moving half the speed of light measure the laser beam to be moving at the speed of light.

How can this be? Well Einstien came up with the idea of time dialation. If you are moving very very quickly, or if you are close to something really massive, time moves slower than someone who isn't moving or further from large masses. Thus you have time travel. If someone is moving really fast, time travels slower in thier reference frame, but faster everywhere else. So if someone were to travel at 86% of the speed of light time would move exactly half as fast for them as it would for everyone else, and when he stopped he would find that he was gone twice as long as his watch measured.

In the last couple of decades, in order to test out this theory they flew an atomic clock around the world a couple of times (thus slightly increasing its speed and distance from a massive object i.e. the earth) The they measured it with an atomic clock at rest. It turned out the one that was moved ran fractions of milliseconds slower because it effectivly traveled into the future.

As for time travel into the past, I've got one simple argument against that working, then a theoritical way it could work without any of the problems it would cause.
First, if there was time travel, we would have known about it the minute the US patent office opened up. Hah, my arguement is now unbeatable!

Now, there is a theory I can almost accept for time travel to the past.
First you take a wormhole at rest, then you make another wormhole linked to it that is traveling at nearly the speed of light. Because you jump between to greatly differing dialation rates its possible to arrive before you left. The problem is, that you can't move quickly enough to arrive back at your starting location before you left, nor can you send a message fast enough. Thus, you can't create a paradox, but you still can "effectivly" travel backwards in time. The reason we haven't had anyone visit from the future is that you couldn't jump back to a point before the time travel device exsisted.

[SSJ112]

Beldizar: you seem to know physics quiet well... but its not to say your arguement is unbeatable.

the faster you go, the slower time goes. this means, that 4 years traveling at near-light speed, may be, for the traveler only 4 minutes.

now, every paradox submited, has been taken care of.
the 'mad scientist paradox' is the most well known, so i will use it.
A mad scientist invents a time machine, and goes back in time. he finds his mother and kills her, if so how could he be born at all? and if he wasn;t born, how come he killed his own mother?
to these questions, there are 2 answers:

1) he would never suceed in killing her, and 'fate' will plan it in a way, in which there is no way for him to do it. (i will say why this is wrong later)

2) he would not go back in time at all, he would simply go to a parallel universe, and kill NOT his mother, but the mother of him in another universe. ( i will explain why this sucks later, and why it is the closest thing to time travel we can achieve)

3) **** would happen. the universe will collapse in unimaginable scale.

why 1 is wrong: there is no way for his arrival not to change the quantom calculations being made all the time. his presence there would set a billion more paradoxes loose, and will most likely cause 3.

about 2: this isn't time travel. not exactly. the mad scientist would only think he has traveled back in time, while he only changed universes. however, this is probably the best we can get - there are no (major) paradoxes in this possiblity...

about 3: the most likely solution, if one would go back in time, for real.

[Bataeu]

I write to you all from the future!
It is 11.30 AM on Tuesday Morning... the 10-02/2004!!!

MWAHAHAHAHAHAHAHA!!!!

[Gundam08]

Apparently it has been proven that we can travel through time, but I don't see why w would want to mess with it.

[End_of_Eternity]

it is possible!

only to the future tho. 0.o

at truely immense speeds, time slows down... and an object at the speed of light would not experience time AT ALL.... but... only something with no mass could travel at the speed of light.

anyways... all we have to do to go to the future is get on a REALLY fast spaceship, fly somewhere, and fly back!

some random astronauts have been shown to be younger (by a small fraction of a second) than they would have been if they hadn't gone into orbit — the speed they were traveling at slowed time down and produced said effect.

i don't really understand it myself, but its some effect of the fact that light waves of things happening don't catch up as quickly when you're traveling away from them or something — meh

[Filez]

Fellas, what do you think, can we travell through time?
I think it is possible, but only in the future. We can travell by different means: one of them could be freezing and the other extremly high speed (speed of light OR faster). We currently can't use any of them. Here's why: If we are frozen the ice crystals would destroy our cells. We would need special ways of freezing. So, that option is executable, just not yet, but it might be soon.

The second one goes like this:

Time is a bent line, along which we move. Now, if we could travel in a staright line, that wold be time-travelling, right? So, how do we move through time in a straight line? I think that that is possible with great speed. But there are minor problems: How could we reach such high speed? If we could gather energy from black matter, we could probably reach such speed. But IF we could gather it from black matter. Another problem is such: if we would be able to travel through time like so, we could do it only in space. And we would go to completly other side of space.

So, what do YOU think?

I think it is impossible with our current technology. We probably wont discover time travel any time soon. Though the future ahead of us might have a chance.

[Gossamer Wings]

Even IF we could travel through time, we would have to figure out the exact PLACE the Earth was in at that particular time, down to the second. Not to mention that the earth does not move around in neat little circles. It is on an axis, and the revolutions are elliptical. The Earth spins at approximately 1000 miles per hour at the equator, and travels through space at 67,000 mph. One decimal place's difference in your calculations could have you in the ocean. Even with these painstaking mathematical calculations, factors like the expansion of the universe come into play.

Sci-Fi movies that show the time machine traveling back to the Tertiary period are ridiculous. Chances are, if you traveled back in time, you'd end up in outer space.

[Kyuu]

Sci-Fi movies that show the time machine traveling back to the Tertiary period are ridiculous. Chances are, if you traveled back in time, you'd end up in outer space.

Correct. People seem to forget that the Earth IS indeed moving.

[sathos]

I think with time travel right now we can only speculate. 50 years ago (or even less), no one would have thought cloning was possible, but now we're getting very close to doing so.

[Agent Orange Skies]

I seriously think traveling throughout time is just a stupid fantasy..

[Okonomiyaki Is Love]

I wrote a paper on this once. I think that when we sleep that there is some sort of time travel...not into the past exactly. But when our conscious mind is shut down, we have no sense of time. I don't think we could ever harness that though. But I just think it's neat cause time seems to move faster when you sleep ^_^

Kendal.

[Heartless Archangel]

I doubt time travel is possible...I don't even give it a second thought...the fact is there's basically no way to, either way you'll probably end up dead or looking like a moron for trying...and besides why would you wanna? I say don't mess with nature, it isn't right.

yeah i agree with sarah... i guess it will remain human race's dream... i think its so impossible...

[Fa113n_Demon]

Beldizar explains how Einstein's special theory of relativity states how it is theoretically possible to move through time at an accelerated rate. But,there's a major flaw in time travel at the moment. In order to actually attain the speed required to move backwards in time a machine is needed.

This is where it get's confusing as an object gets closer to the speed of light the force of drag upon it is increased exponentially. This in turn means that A. enough thrust required to combat the drag upon the object or B. it losses all of its mass. This can be done near a black hole. Which of course is a celestial object of infinate gravitational force. This force an be used as a source of thrust. There is said to be a point inside a black hole known as the point sigularity where all of its gravitaional force comes from.

There is currently nothing man made that can reach to this point of infinite gravity. Thus currently using this method is not possible. In one of Einsteins books he mentions space and time a giant rubber pad. within this there are dents caused by black holes where space and time can become distorted.

Amzingly man can create such distortion on earth without fear of destroying himself. This is done through the us of lasers. Light if properly channeled can create mini distortions in time and space so if u combine a lot of these powerful lasers it is theoretically possible to supass light speed and travel at a higher "ethereal" plane where one can move through time at his/her leisure.

This poses another problem if we could travel back in time why haven't we met anyone from the future. Essentially we haven't done so because there is nowhere for them to materialize. Slow down and become stable again.
so in essence when the first time machine is turned on anything sent back from the future will reappear there. making the idea of stopping crucial events in history due to time travel impossible. well thats my arguement

By the way this is actually true stuff I berkley labs i think is building it as you read this.

[*Overlord*]

I believe its very possible just read this:
Do the laws of physics permit time travel, even in principle? They may in the subatomic world. A positron (the antiparticle associated with the electron) can be considered to be an electron going backward in time. Thus, if we create an electron-positron pair and the positron later annihilates in a collision with another, different electron, we could view this as a single electron executing a zigzag, N-shaped path through time: forward in time as an electron, then backward in time as a positron, then forward in time again as an electron.

The probability of a macroscopic object — like a human — doing this trick is infinitesimal. But thanks to Albert Einstein we know that time travel of a different sort does happen in the macroscopic world. As he showed back in 1905 with his special theory of relativity, time slows down for objects moving close to the speed of light, at least from the viewpoint of a stationary observer. You want to visit the earth 1,000 years from now? Just travel to a star 500 light-years away and return, going both ways at 99.995% the speed of light. When you return, the earth will be 1,000 years older, but you'll have aged only 10 years. I already know a time traveler. My friend, astronaut Story Musgrave, who helped repair the Hubble Space Telescope, spent 53.4 days in orbit. He is thus more than a millisecond younger than he would have been if he had stayed home. The effect is small, because he traveled very slowly relative to the speed of light, but it's real.

With more money, we could do better in the next century — but only a little. If we sent an astronaut to the planet Mercury and she lived there for 30 years before returning, she would be about 22 seconds younger than if she had stayed on Earth. Clocks on Mercury tick more slowly than those on Earth because Mercury circles the sun at a faster speed (and also because Mercury is deeper in the sun's gravitational field; gravity affects clocks much as velocity does). Astronauts traveling away from Earth to a distance of 0.1 light years and returning at 1% the speed of light would arrive back 8.8 hours younger than if they hadn't gone.

The downside of traveling into the future this way is that you might be stuck there. Is there any way of going backward in time? Once again, Einstein may have provided the answer. His 1915 theory of general relativity showed that space and time are curved, and that the curvature can be large in the neighborhood of very massive objects. If an object is dense enough, the curvature can become nearly infinite, perhaps opening a tunnel that connects distant regions of space-time as though they were next door. Physicists call this tunnel a wormhole, in an analogy to the shortcut a worm eats from one side of a curved apple to the other.

In 1988, Kip Thorne, a physicist at Caltech, and several colleagues suggested that you could use such a wormhole to travel into the past. Here's how you do it: move one mouth of the wormhole through space at nearly the speed of light while leaving the other one fixed. Then jump in through the moving end. Like a moving astronaut, this end ages less, so it connects back to an earlier time on the fixed end. When you pop out through the fixed end an instant later, you'll find that you've emerged in your own past.

The problem with wormholes is that the openings are microscopic and tend to snap shut a fraction of a second after they're created. The only way to keep them open, as far as we know, is with matter that has negative density. In layman's terms, that's stuff that weighs less than nothing. This may sound impossible, but the Dutch physicist Hendrik Casimir theorized in 1948 that holding two plates of electrically conducting material very close together in a vacuum actually does create a region of negative density that exerts an inward pressure on the plates. The force predicted by Casimir has been verified in the laboratory.

Using this idea, Thorne and his colleagues proposed constructing a wormhole tunnel 600 million miles in circumference, with Casimir plates separated by only 400 proton diameters at the midpoint. Time travelers would have to somehow open doors in these plates to pass through the wormhole. The mass required for construction? Two hundred million times the mass of the sun. These are projects only a supercivilization could attempt — not something for 21st century engineers.

In 1991 I found another possible mechanism for time travel using cosmic strings, thin strands of energy millions of light-years long, predicted by some theories of particle physics (but not yet observed in the universe). You could try to construct a cosmic-string time machine by finding a large loop of cosmic string and somehow manipulating it so it would contract rapidly under its own tension, like a rubber band. The extraordinary energy density of the string curves space-time sharply, and by flying a spaceship around the two sides of the loop as they pass each other at nearly the speed of light, you'd travel into the past.

To go back in time by one year, unfortunately, you'd need a loop containing about half the mass-energy of an entire galaxy. Worse yet, the contracting cosmic-string loop would probably trigger the formation of a rotating black hole, trapping any time-travel regions inside. You would almost certainly be torn apart by near infinite space curvature before you could travel anywhere. Even if you could get past these difficulties, the physics of both types of time machine dictate that you can't go back in time to an epoch before the time machine was created. So you couldn't meet and perhaps kill your own ancestor. But if such a machine were built today, your descendants might come and kill you, changing their own past.

Some argue conservatively that time travelers don't change the past; they were always part of it. On the other hand, paradoxical though this sounds, a version of the many-worlds theory of quantum mechanics (see "Will We Discover Another Universe?" in this issue) devised by Oxford physicist David Deutsch might allow such history-changing visits. In this picture, there are many interlacing world histories, so that if you went back in time and killed your grandmother when she was a young girl, this would simply cause space-time to branch off into a new parallel universe that doesn't interfere with the familiar one.

Stephen Hawking has addressed the problem in a different way, proposing what he calls a chronology-protection conjecture. Somehow, he argues, the laws of physics must always conspire to prevent travel into the past. He believes that quantum effects, coupled with other constraints, will always step in to prevent time machines. The jury is still out on this question. We may need to develop a theory of quantum gravity to learn whether Hawking is right.

So, will we time-travel in the next century? Travel to the future — yes, but only in short hops, I suspect. To the past — very likely not. Such travel is expensive, dangerous and subject to quantum effects that may or may not spoil your chances of coming back alive. Those of us working in this field aren't rushing to the patent office with time-machine blueprints. But we are interested in knowing whether time machines are possible, even in principle, because answering that question will tell us where the boundaries of physics lie and provide clues to how the universe works.

[Kyuu]

Hey, you Darkfox... where did you get that little tidbit?

[*Overlord*]

Hey, you Darkfox... where did you get that little tidbit?

I got it from here. http://www.time.com/time/reports/v21/science/time.html and the reason i choose these website's resources is because it actually state facts, and not proposals.

[Beldizar]

Just wanted to pipe in and correct a few physics errors.


This is where it get's confusing as an object gets closer to the speed of light the force of drag upon it is increased exponentially. This in turn means that A. enough thrust required to combat the drag upon the object or B. it losses all of its mass. This can be done near a black hole. Which of course is a celestial object of infinate gravitational force. This force an be used as a source of thrust. There is said to be a point inside a black hole known as the point sigularity where all of its gravitaional force comes from.

Drag has nothing to do with it. Drag is simply friction, which you won't have much of in space. The density in space is such that you'll hit a single atom something like every 5 meter or so. As an object approaches the speed of light, increasing speed becomes tricky one a few accounts. First, to accelerate, you have to eject fuel exaust to propel yourself forward. The exaust has to be ejected at faster speeds than you are moving or you won't accelerate. This means you've got to be using light to accelerate to near light speed. The second problem is you have general relitivity effects occuring. As you try to accelerate, you gain more kinetic energy, and the more energy you have, the more difficult it is to acclerate further. Also, the more energy you have, the more time dialation occurs. Thus someone traveling at 86% of the speed of light is going to have a good deal of kinetic energy, and time will be slowed by half. It gets complecated and I'll explain it if someone really wants to know, but you get all sorts of funky problems with this because simultanitiy goes out the window at this point.

Second, when objects approach the speed of light, their mass in thier own reference frame does not change. Their mass in another reference frame does change however, and the closer they get to C, the more massive they appear to an observer at rest.

Black holes do not have infinite gravitational force. As far as relitivity goes, there isn't such thing as gravitational force. Black holes do however have infinite space-time curvature, meaning they are basically a bottumless pit on a rubber grid that would repersent space-time. If black holes had infinite gravitational force, we'd all be sucked into them immediately. They do have really strong gravitational force (using classical physics) but its not infinite.



Amzingly man can create such distortion on earth without fear of destroying himself. This is done through the us of lasers. Light if properly channeled can create mini distortions in time and space so if u combine a lot of these powerful lasers it is theoretically possible to supass light speed and travel at a higher "ethereal" plane where one can move through time at his/her leisure.

Ether was an old physical principle long since disproven. Someone pointed out that all waves have to travel through a medium, so light must have a medium, and I name it Ether. To test this theory, they tried doing percise measurments of the speed of light as the earth moved through this feild of ether, one at sunrise, and one at sunset, that is, the two points when the point directly above the labratory is tangent to the path of the earth around the sun. It was found that at both times, and at all times, the speed of light did not change, thus there was not medium which light traveled through.

The idea about powerful lasers can create time distortions, but it requires a great deal of energy focused on a small point. Space-time warping, as I've said occurs in areas of high energy density, such as objects with high kinetic energy, or objects with great mass.



darkmarlfox's post has some good stuff on it, I read that artical back in highschool, so it is a bit dated, but nothing new has come out in the last 3 years to my knowledge. And oh, Darkmarlfox, its a good idea to use quotes and site your sources, otherwise its kinda plagurism.

[KenshinX]

I believe in the multiple quantum universe theory of spacetime.

In this theory you can travel back in time using cosmic strings (or other such things) and travle forward in time by sitting next to a black hole (or traveling near the speed od light). You can also change the past in any way you want because you do not belong to that quantum reality. The only reality that you couldn't change is your own quantum reality. If you changed your own quantum reality your quantum universe would not exist.

The way that you would be able to travel back in time is to go to annother quantum universe that is symiliar to ours but started a few years later (using the big bang theory). You could go forward in time using the clasical methods or by switching quantum universes.

[Cory Nelson]

Time travel is indeed possible, Zak and I are living proof of that. Many of you are confused however, especially on the subject of paradoxes, which simply do not exist. When traveling back in time, you are not actually going back in time, you are simply transported into a different worldine. These worldlines are infinite; none are 100% the same either. There is an aproximate 2.762...% difference between this worldline, and the worldline I come from, though this number increases as you push further back in time. Considering the fact that you are in a completely different world line, the events that occur in that worldline would in no way effect yours. Therefore, if you were to say, kill your grandfather, would you be born? Not on that worldline, but yes, you would still exist in your own world. Try to understand as best you can, if you have any questions feel free to ask me.

[KenshinX]

That is exactly what i was trying to say.
What you say is synominous with the multiple quantum realities theory. :)

[Psychotic]

Heh, this is indeed a very good subject for debate, and the many theories that have been presented are very interesting.

I personally find the concept of time travel into the past very hard to believe. Though, in theory it may appear to be possible somewhere far off in the future, there are so very many things to take into account... And even if it is achieved someday, it would be nothing phenomenal like portrayed in the theater. I think what bothers my mind the most about time travel is the idea of 'what could be changed'. Of course there is the theory that to meet someone traveling back in time, you would have done so already the first time around, before that person even traveled back. Does that mean that in that instance in time there would be two 'time travelers' existing? Of course, then there's always the theory of the multiple timelines (as KenshinX mentioned, the Multiple Quantum Realities theory). And just how far does this theory stretch? In essence, to consider it, every time we face a decision, we create a new possible reality. And since the average human faces decisions practically every second of their lives, the infinite amount of possible realities is staggering.

All in all, the idea of time travel into the past is something that makes my 17 year-old head throb. So many what ifs are contained within every aspect of it, that though I find it very interesting to ponder, I find it quite frustrating as well. Just like when I think of how the Bible states that 'God has always been.' With my narrow human concepts of time, it is near impossible to grasp that God has 'always been', and did not have a beginning. Know what I mean? Things such as these I try not to think about too often. XD

As for travel into the future, that is something I find a bit more plausible. As was stated about the astronauts, it is indeed possible to some extent. Though time travel in that essence is more a slowing down of one's own aging process by traveling at such high speeds. But still, with this theory it would indeed be possible to travel into the future.

Well, that's my two cents. Now I'll get back to thinking about less complicated things, such as, what kind of drink I'm going to have, and how I really don't want to go to work tomorrow. XD

[KenshinX]

What you said is corect but you forgot to mention (as did I) that the laws of quantum mechanics dictate that particles spontianiously appear with their antiparticle and then disapear. And since we cannot predict when and where the particles will appear they can be treated as decisions and therefore we have more quantum realities than you think.

[kaoru']

In order to travel through time you have be traveling faster then the speed of light which is 186,000 miles a second, which can travel 4 times around the earth in one second, so I think it would be pretty hard to create a machine that could travel that fast.

[Kyuu]

How fast does time move when yer "shagging" someone? :twisted: :twisted: :lol:

[jubei_massages_goku]

We will never travel through time. I hate to tell everyone, but time is also a human invention. Think about it: do you see any random numbers in the heavens? This is pretty f***ed-up: H.G. Wells wrote a sci-fi novel, and now we start believing it's possible. I think I'll start looking for some hobbits tomorrow. Maybe I'll get Han Solo to fly me around. As long as Aslan the lion is there to philosophize. I hope we don't run into the Predator.

[joonavar]

*thinks her eyes are bleeding from reading so much scientific jargon*

there are definitely some ppl on here that know a lot about this subject.

I am still confused about this whole theory. Perhaps it is not impossible..but it is very much far fetched too.

the theories on time travel are all there, we have all seen the movies and read books on the topic..but what would realistically be the benefits? - changing something in the past or future, for the greater good, could infact create bigger demons than were there initially..
knowing human nature, scientists will not rest until they conquer and control the whole concept of time.
If it is possible, it definitely won't be happening in our lifetime.
and if it is possible..would you REALLY want to control it?..afterall..look at the image that movies like Butterfly Effect and Terminator conjure up.

people want to time travel to erase such things like wars happening, etc..but instead of that, why doesn't the government stop getting themselves into these radiculous messes in the frist place...that way we could all be content with the present world that we live in

[Sonnay]

ok i think it could be possible butt ithink it would be pretty weird and plus y we disccussing this i mean cmon but still its possible

[IanTheAmerican]

scientific american did a good article on time travel a while ago... i should try to find that article.

my opinion: time travel would be worthless anyway... unless it was used for no interaction purposes... like studying extinct animals and **** like that.
Reason 1: ok, hypotheitical situation. You broke your leg. It stoped you from doing something you really wanted to do. Your dissapointed. you some how build a time machine and go back in time. You CANNOT change the fact that you broke yur leg if it is the reason you built the time machine, because your past self, without a roken leg, would se no purpose in doing so, creating A.) horrible flux/disortion in time. or B.) Catastrophic collapse in the universe. I think this will be caused because of a infinite loop of realities. back to hypothetical story: But if you broke your leg because you stopped your self from not breaking your past leg then you'd still try to stpo yourself from braking your leg. thus repeating the cycle of stopping yourself from breaking your leg yet never being succesful at it.

sry if that was a litle too mumbo jumbo and strange... :wink:
simple theroy: you have 2 billard balls though they are the same they are in different times. You knock the future billard into a time maching sending it back 5 seconds into the past, this billard ball CANNOT change the path of it's past self so that it cannot go into the past, via the time machine.

did that make a little more sense? :?

kyuu: as they say... time flys when ur having fun!!! :twisted:

[Silver's Shadow Tamer]

If time travel is possible, then how come we haven't met any travelers from the future?

Knowing humans, someone would go into the past and actually interact with the point of time that they would travel

Very true, and you have to remember, time is measurement that humans made up.
Who knows, maybe there is no such thing as time, but it's something else.
I believe that if humans made up the measurement time, than how can we understand it if we just labled it?
But that's just me...I make no sense. O.O And I'm only 13. I'm too young to think about pyschics and stuff like that. (SP?)

[Yousuke]

I don't believe we can go backwards in time. Not until scientists tell me that time reversal invariance is true for weak interactions or tell me that they have driven stuff to FTL speeds. :P

http://www2.slac.stanford.edu/vvc/theory/timereversal.html
http://www2.slac.stanford.edu/vvc/theory/weakinteract.html

[a n i m u ^______^]

lol, in the movie Napolean Dynamite, they buy a time machine off e-bay or something and it is this ridiculous thing that obviously doesnt work. I dont think it is possible to travel through time, what a ridiculous thought

[IHateGod]

Fellas, what do you think, can we travell through time?
I think it is possible, but only in the future. We can travell by different means: one of them could be freezing and the other extremly high speed (speed of light OR faster). We currently can't use any of them. Here's why: If we are frozen the ice crystals would destroy our cells. We would need special ways of freezing. So, that option is executable, just not yet, but it might be soon.

The second one goes like this:

Time is a bent line, along which we move. Now, if we could travel in a staright line, that wold be time-travelling, right? So, how do we move through time in a straight line? I think that that is possible with great speed. But there are minor problems: How could we reach such high speed? If we could gather energy from black matter, we could probably reach such speed. But IF we could gather it from black matter. Another problem is such: if we would be able to travel through time like so, we could do it only in space. And we would go to completly other side of space.

So, what do YOU think?

Science tells us if we move at light speed all mass is being converted to energy. Not a single material can maintain its mass.

Basically time does not exist, as it is just the difference between the beginning point and the endpoint of an event or a series of events.
Time is a man-made concept and basically it does not exist. Every second is a clocktick, every period a series of events. Time would freeze if there would be no events in the complete universe. How could you go to the past, as you can't make actions undone? Even if you would restore everything back the way it was, it would not be the past, because it is another series of events.

We see the current "time", because the light shines at that direction. If we would be able - and I clearly say IF - to move faster than light, we would see an impression of the past. This way we even view stars at the sky that have already died, because their light has not reached us yet. Did you know we see the sun 1 second in the past?

[Hayami699]

Why does it have to be that way? Why must lightspeed be the eternal constant of the universe? Just becuase it takes such amount of time for light to reach us from a certain object doesn't mean we are that amount of time "behind" them on the time scale. I find this thinking simply illogical and faux.

Light isn't truly defined yet becuase current technology cannot completely do so. Most science books, if not all, will tell you this. Scientists guess that they "know" how fast light is and how it moves (or even what it is, particles or waves or both?), but they aren't completely certain yet.

Even if current scientific standings of the definition of light are completely accurate without any doubt, I simply cannot beleive that lightwaves are the constant of the universe. I mean, why would they be? Becuase they go really, really fast? Or becuase we can't slow them down? Typical scientist manner of thought; the human race can't alter it therefore it MUST be the universal constant. I mean come on! Can anyone tell me why light defines time without referencing it's friggin' velocity? Anything can travel fast. I think matter can travel as fast as light with the proper propulsion. Why not? Is light really "infinately unreachable" by physical mass? If so, why? Why do scientists say matter must have "infinate" energy to reach lightspeed? Someone please make an attempt at this.

[IHateGod]

Why does it have to be that way? Why must lightspeed be the eternal constant of the universe? Just becuase it takes such amount of time for light to reach us from a certain object doesn't mean we are that amount of time "behind" them on the time scale. I find this thinking simply illogical and faux.

Light isn't truly defined yet becuase current technology cannot completely do so. Most science books, if not all, will tell you this. Scientists guess that they "know" how fast light is and how it moves (or even what it is, particles or waves or both?), but they aren't completely certain yet.

Even if current scientific standings of the definition of light are completely accurate without any doubt, I simply cannot beleive that lightwaves are the constant of the universe. I mean, why would they be? Becuase they go really, really fast? Or becuase we can't slow them down? Typical scientist manner of thought; the human race can't alter it therefore it MUST be the universal constant. I mean come on! Can anyone tell me why light defines time without referencing it's friggin' velocity?


I think you misunderstood me. Time travel is impossible.
I wasn't stating that we are "behind" in time if the light hasn't reached us yet. I stated that we "view" an impression of an object in the past. Without light there is no sight. Whenever light reaches the eye an impression (view) of an object is created from the exact time the light beam was sent. If the light takes b.e. 10 years to reach us, we "view" that object as it was 10 years ago. Light does not define time, a series of events does. Light defines the impression of a certain object at that "time". Our sight is an impression of the real objects around us.
We don't need to know the speed of light in order to know at what "time" we see an object, as light defines our sight.

Besides, the speed of light has been measures. Read "Measurement of the speed of light".

http://en.wikipedia.org/wiki/Speed_of_light



Anything can travel fast. I think matter can travel as fast as light with the proper propulsion. Why not? Is light really "infinately unreachable" by physical mass? If so, why? Why do scientists say matter must have "infinate" energy to reach lightspeed? Someone please make an attempt at this.

That's right, anything can travel fast. But when an object travels as fast as light, all mass is being converted to energy. This explains the big bang theory perfectly, because there was only mass at the start. The particles accelerate at nearly light speed and lose some of their mass which is being converted to energy. How would energy be able to exist, if their was no movement? It wouldn't. Energy can form gasses, which can form planets, mass, of their own.

[Animeguy245]

Fellas, what do you think, can we travell through time?
I think it is possible, but only in the future. We can travell by different means: one of them could be freezing and the other extremly high speed (speed of light OR faster). We currently can't use any of them. Here's why: If we are frozen the ice crystals would destroy our cells. We would need special ways of freezing. So, that option is executable, just not yet, but it might be soon.

The second one goes like this:

Time is a bent line, along which we move. Now, if we could travel in a staright line, that wold be time-travelling, right? So, how do we move through time in a straight line? I think that that is possible with great speed. But there are minor problems: How could we reach such high speed? If we could gather energy from black matter, we could probably reach such speed. But IF we could gather it from black matter. Another problem is such: if we would be able to travel through time like so, we could do it only in space. And we would go to completly other side of space.

So, what do YOU think?

Maybe but strict rules will be put on it like "Dont touch anything! It could alter time!" like that story "A Sound of Thunder" I think thats what its called.

[Hayami699]

I understand what you were saying, I just midread it.

I know that "c" has been measured and is beleived to be constant in a vacuum, but light can slow in a physical medium. Why can't it be speed up?

Another source told me if two spaceships traveling 50% the speed of light each approached each other, they could only observe the other traveling 99.9% the speed of light because of the laws of Einstein's theory. I find that hard to beleive, seeing as how two cars each traveling fifty miles and hour approaching each other would see the other moving one hundred miles an hour. And explanation?

Also, if a spaceship were traveling the speed of light, a motionary observer and a ship that was fallowing it albeit slower than it would see it at the exact same places at the exact same times, fallowing the theory that lightspeed doesn't owe to the velocity of the object it reflects off of. This too fallows the Einstein theory. Wouldn't this mean that light can travel two speeds at once? I just find this all absurd.

[IHateGod]

I understand what you were saying, I just midread it.

I know that "c" has been measured and is beleived to be constant in a vacuum, but light can slow in a physical medium. Why can't it be speed up?


Because vacuum (nothing) has a zero density. The higher the density, the more it slows down. There exists no negative density. In water, p.e., light is slowed down very slightly. There is however one way to speed it up. Black holes can "suck" light in, but this has nothing to do with density.



Another source told me if two spaceships traveling 50% the speed of light each approached each other, they could only observe the other traveling 99.9% the speed of light because of the laws of Einstein's theory. I find that hard to beleive, seeing as how two cars each traveling fifty miles and hour approaching each other would see the other moving one hundred miles an hour. And explanation?


I think this is logical. Suppose the following example. You sit in a immobile train and watch how another train moves at 50 km/h. You would have the idea you're moving yourself at 50 km/h. Now if both trains move in opposite directions at 50 km/h, you get the impression you move at 100 km/h. Movement is a displacement between two objects. Both objects displace 50 km/h away from each other => 50 * 2 = 100 km/h. This is logical.

Another example:
We both have the same amount of dollars. I give you 2 of mine. Now you have 4 more than I do. That's mathemathics.

x=y
<=>x-y=0

(x+2)=(y-2)
<=>x+4=y

Here, there is an offset in opposite directions as well (-2 and +2).




Also, if a spaceship were traveling the speed of light, a motionary observer and a ship that was fallowing it albeit slower than it would see it at the exact same places at the exact same times, fallowing the theory that lightspeed doesn't owe to the velocity of the object it reflects off of. This too fallows the Einstein theory. Wouldn't this mean that light can travel two speeds at once? I just find this all absurd.

If a ship would travel at light speed, there would only be energy left. So I think, you wouldn't be able to seethe ship at all. However, a motion tracker might be able to track the energy as well, but the speed of the object will be changed once it has become energy.

I don't think this example is true.
You can never see an object at the exact same time, because there is always a very small distance the light has to accross to touch your eyes.

If an 2 objects are moving and one moves slower, than the distance will always become greater.

The way we see an object at this time is decided by the following factors:
- the distance between the two points (in this example it will keep increasing)
- the density of the mass through which the air has to pass

[Yousuke]

I understand what you were saying, I just midread it.

I know that "c" has been measured and is beleived to be constant in a vacuum, but light can slow in a physical medium. Why can't it be speed up?


Because vacuum (nothing) has a zero density. The higher the density, the more it slows down. There exists no negative density. In water, p.e., light is slowed down very slightly. There is however one way to speed it up. Black holes can "suck" light in, but this has nothing to do with density.
Rubbish.
1. Light "passing through" matter is slowed down because the electronic and magnetic components of light(light is a variant of "electromagnetic radiation") interact with atoms.
2. Light cannot be speeded up faster that it already is. Light falling into a "gravity well" does not gain speed, it is blue shifted. Likewise, light going up a "gravity well" does not slow down, it is red shifted.




Another source told me if two spaceships traveling 50% the speed of light each approached each other, they could only observe the other traveling 99.9% the speed of light because of the laws of Einstein's theory. I find that hard to beleive, seeing as how two cars each traveling fifty miles and hour approaching each other would see the other moving one hundred miles an hour. And explanation?


I think this is logical. Suppose the following example. You sit in a immobile train and watch how another train moves at 50 km/h. You would have the idea you're moving yourself at 50 km/h. Now if both trains move in opposite directions at 50 km/h, you get the impression you move at 100 km/h. Movement is a displacement between two objects. Both objects displace 50 km/h away from each other => 50 * 2 = 100 km/h. This is logical.

Another example:
We both have the same amount of dollars. I give you 2 of mine. Now you have 4 more than I do. That's mathemathics.

x=y
<=>x-y=0

(x+2)=(y-2)
<=>x+4=y

Here, there is an offset in opposite directions as well (-2 and +2).
More rubbish.
The two spaceships traveling towards each other near the speed of light won't approach each other faster than the speed of light because of time and space distortion. This is described in the Lorentz transformations. Basically, the closer your velocity gets to the speed of light, the greater the distortion.
http://en.wikipedia.org/wiki/Lorentz_transformations





Also, if a spaceship were traveling the speed of light, a motionary observer and a ship that was fallowing it albeit slower than it would see it at the exact same places at the exact same times, fallowing the theory that lightspeed doesn't owe to the velocity of the object it reflects off of. This too fallows the Einstein theory. Wouldn't this mean that light can travel two speeds at once? I just find this all absurd.

If a ship would travel at light speed, there would only be energy left. So I think, you wouldn't be able to seethe ship at all. However, a motion tracker might be able to track the energy as well, but the speed of the object will be changed once it has become energy.

I don't think this example is true.
You can never see an object at the exact same time, because there is always a very small distance the light has to accross to touch your eyes.

If an 2 objects are moving and one moves slower, than the distance will always become greater.

The way we see an object at this time is decided by the following factors:
- the distance between the two points (in this example it will keep increasing)
- the density of the mass through which the air has to pass
Damn it, more rubbish.
Light "appears" to move in different speeds because of, again, space-time distortions at near-light speeds.





Anything can travel fast. I think matter can travel as fast as light with the proper propulsion. Why not? Is light really "infinately unreachable" by physical mass? If so, why? Why do scientists say matter must have "infinate" energy to reach lightspeed? Someone please make an attempt at this.

That's right, anything can travel fast. But when an object travels as fast as light, all mass is being converted to energy. This explains the big bang theory perfectly, because there was only mass at the start. The particles accelerate at nearly light speed and lose some of their mass which is being converted to energy. How would energy be able to exist, if their was no movement? It wouldn't. Energy can form gasses, which can form planets, mass, of their own.
Light speed is unreachable because the time-space distortion increases as you approach the speed of light. The distortion happens in such a way that it requires more and more kinetic energy to push an object as it approaches the speed of light.

[(|\|)Setsunayaki{/\/}]

Fellas, what do you think, can we travell through time?
I think it is possible, but only in the future. We can travell by different means: one of them could be freezing and the other extremly high speed (speed of light OR faster). We currently can't use any of them. Here's why: If we are frozen the ice crystals would destroy our cells. We would need special ways of freezing. So, that option is executable, just not yet, but it might be soon.

The second one goes like this:

Time is a bent line, along which we move. Now, if we could travel in a staright line, that wold be time-travelling, right? So, how do we move through time in a straight line? I think that that is possible with great speed. But there are minor problems: How could we reach such high speed? If we could gather energy from black matter, we could probably reach such speed. But IF we could gather it from black matter. Another problem is such: if we would be able to travel through time like so, we could do it only in space. And we would go to completly other side of space.

So, what do YOU think?

Time affects people differently. Some are sensitive to it. Others are not. I don't want to type a 10 page post of how its posible and proven that time can react to others in different ways in theory. I would like you to know the information is out there and its not my job to educate you.

[IHateGod]

Rubbish.
1. Light "passing through" matter is slowed down because the electronic and magnetic components of light(light is a variant of "electromagnetic radiation") interact with atoms.
2. Light cannot be speeded up faster that it already is. Light falling into a "gravity well" does not gain speed, it is blue shifted. Likewise, light going up a "gravity well" does not slow down, it is red shifted.


It's not rubbish; it's text.

1.If bullets are slowed down through water, it is also because their atoms interact with those of the water. Otherwise the density would have no effect. That's actually what I meant. If atoms of several materials wouldn't interact with each other, there would be no slowing down off course. This is a stupid argument, it is not a counterargument. It explains what I just stated.
Why are your feet stuck in the mud? Because atoms interact with each other; there is cohesion force. Thus, there is correlation between the density and the decreasement of movement speed of material or energy.

2. a. I was talking about the speed of light, not the "observable" speed of light. How can you be so convinced that the speed of light cannot be increased? Bring me a prove, please.
b. Blue shifting and red shifting has no effect on the speed of light. It increases or decreases the length of the energy wave and even slightly its color. As far as I know the length of the wave shows no correlation with its speed.

Light can be speeded up. Black holes can suck light beams, even if it move at the opposite direction. I've read this in a magazine and saw a picture of it. Whether it was a sattelite photograph or an animated image, I don't know. If light moves towards the same direction as the black hole is sucking, it will gain speed, because black holes have such a powerful absorption force that the speed of light is minor compared with it.



More rubbish.
The two spaceships traveling towards each other near the speed of light won't approach each other faster than the speed of light because of time and space distortion. This is described in the Lorentz transformations. Basically, the closer your velocity gets to the speed of light, the greater the distortion.
http://en.wikipedia.org/wiki/Lorentz_transformations


First of all the Lorentz formula is known to be identified as a limiting case, when v is low enough with respect to c. Mathemathics often contains limiting cases and thus they give not exact calculations.
The Lorentz transformations contain distortion in some cases, because it is not fully accurate.

There is also a difference between the "observable" light speed and the actual light speed. I citate


Although it seems counter-intuitive, light will be seen to move at the speed of light regardless of the frame of reference of the observer. A flashlight in a moving train will not produce light with a speed in excess of the speed of light. Both an observer in the train and one on the stationary platform will measure the same speed of light, in reference to their own reference points. This results in the Lorentz transformations; observers moving with respect to one another do not agree on the size of an object nor on simultaneity. Despite this apparent disagreement, all points of reference are fundamentally equally valid.


from http://en.wikipedia.org/wiki/Faster-than-light

When two objects fly towards each other at light speed, they won't see each other approaching faster than light speed. But they will reach each other twice as fast as light speed.

Do you think 50 % of the light speed is near the light speed?

A prove that light speed can be accelerated:
http://www.raptuready.com/r/resource/speed.html.ra.php

When a team of scientists created laser that sent a pulse of light through a vacuum that was faster than the speed of light.

What you state was also a contradiction with mathemathics. Reconsider the example with the trains. There are several other forms of relativity next to Lorenz as well. Lorenz didn't state that if two objects approach each other at the light speed, they woudln't approach each other twice faster than light speed.



Light speed is unreachable because the time-space distortion increases as you approach the speed of light. The distortion happens in such a way that it requires more and more kinetic energy to push an object as it approaches the speed of light.

You invented this yourself, I guess. Light speed is not unreachable; the universe expands faster than light and it keeps accelerating. If light speed were unreachable, it wouldn't be called "light speed", because light actually has that speed (however maybe not exaclty).
I told before that black holes extreme strong cohesion force. When they would suck material in, it would have greater than "light speed", as light cannot get away from it, even when it flies in the opposite direction.
Considering this, mass would be converted to pure energy.

If i'm not wrong, I recently read somewhere scientists were able to create a black hole in a lab, which lasted for less than 1 ps. It sucked in material which was being converted to some kind of radiation (energy). How do you explain this? Light speed was achieved, otherwise no energy would have set free. There was no material left as well.

The energy that is created when the speed of light is achieved is as next:
E = M * C ²
Where E = Energy, M = Mass and C = the Einstein constant for light speed in vacuum.

Another prove that light speed can be accelerated:
http://www.raptuready.com/r/resource/speed.html.ra.php

When a team of scientists created laser that sent a pulse of light through a vacuum that was faster than the speed of light.

And another:
http://www.newscientist.com/article.ns?id=dn2796

[Yousuke]

Hmm...

No use kicking a dead burro but some questions still need proper answers...

Why does it have to be that way? Why must lightspeed be the eternal constant of the universe? Just becuase it takes such amount of time for light to reach us from a certain object doesn't mean we are that amount of time "behind" them on the time scale. I find this thinking simply illogical and faux.
No one is actually "behind" anyone. We just can't get information from/to other places instantly. For example lets say that Houston have a spaceship one light-hour away in space. It will take the radio signals from the spaceship one hour to reach Houston which means that we have no way of knowing what is happening to the spaceship right now. But it will also take one hour for Houston's radio signals to reach the spaceship which means that the spaceship's crew have no way of knowing what is happening to Houston at the moment. While both are worrying about what is happening at the other end, they are both doing stuff that can be known only one hour later by the other end. When scientists say that "we look backwards in time" when looking at distant objects it simply means that we are looking at very old pictures. Likewise the people of those distant objects, if they exist, will also be looking at very old pictures of our local region of space.

Light isn't truly defined yet becuase current technology cannot completely do so. Most science books, if not all, will tell you this. Scientists guess that they "know" how fast light is and how it moves (or even what it is, particles or waves or both?), but they aren't completely certain yet.
The exact value of the speed of light is irrelevant. The important thing is that it is limited to a finite value which results in some very freaky consequences that is way beyond common sense but still within logic and reason.

Even if current scientific standings of the definition of light are completely accurate without any doubt, I simply cannot beleive that lightwaves are the constant of the universe. I mean, why would they be? Becuase they go really, really fast? Or becuase we can't slow them down? Typical scientist manner of thought; the human race can't alter it therefore it MUST be the universal constant. I mean come on! Can anyone tell me why light defines time without referencing it's friggin' velocity?
Scientists did not write the laws of the universe. That work was already done by the Creator. The scientists just report their findings. They assumed that the speed of light in vacuum is universaly constant because they reasoned it to be so. The Earth is moving at around 30km/sec around the sun yet it's motion has no observable effect on light. It is as if the Earth is standing still. The speed of light is the same whether it is pointed forward of earth's motion or pointed backwards. Therefore, if the speed of light is constant for a moving body, it must be the same for other moving bodies.
link: http://en.wikipedia.org/wiki/Michelson-Morley_experiment

Anything can travel fast. I think matter can travel as fast as light with the proper propulsion. Why not? Is light really "infinately unreachable" by physical mass? If so, why? Why do scientists say matter must have "infinate" energy to reach lightspeed? Someone please make an attempt at this.
This isn't just theory, this is an actual observed fact. Objects with mass greater than 0 cannot be driven faster than cee. Scientists are constantly trying to drive particles with more and more energy but they just can't push them faster than cee.

Cyclotrons reach an energy limit because of the relativistic effects at high energies whereby particles gain mass rather than speed. Though the special theory of relativity precludes matter from traveling faster than the speed of light in a vacuum, the particles in an accelerator normally travel very close to the speed of light, perhaps 99.99%. In high energy accelerators, there is a diminishing return in speed as the particle approaches the speed of light. The effect of the energy injected using the electric fields is therefore to markedly increase their mass rather than their speed. Doubling the energy might increase the speed a fraction of a percent closer to that of light but the main effect is to increase the relativistic mass of the particle.
source: http://en.wikipedia.org/wiki/Particle_accelerator

I know that "c" has been measured and is beleived to be constant in a vacuum, but light can slow in a physical medium. Why can't it be speed up?
It is not light itself which chooses to travel at cee but rather it is the nature of our universe that forces light to travel at cee. Light, or photon, has zero mass yet it has momentum, a function of mass and speed. For an object with zero mass to have momentum it would have to travel at infinite speed. But since this universe is determined to limit everything to travel at cee or slower, massless objects would have to be content with cee.

Another source told me if two spaceships traveling 50% the speed of light each approached each other, they could only observe the other traveling 99.9% the speed of light because of the laws of Einstein's theory. I find that hard to beleive, seeing as how two cars each traveling fifty miles and hour approaching each other would see the other moving one hundred miles an hour. And explanation?
Not enough time to write stuff by my own words so I'll just paste...


A common resistance to the speed limit is to suggest that you just accelerate two different objects to more than half of the speed of light and point them toward each other, giving a relative speed greater than c. But that doesn't work! Time and space are interwoven in such a way that no one observer ever sees another object moving toward them at greater than c. The Einstein velocity addition deals with the transformation of velocities, always yielding a relative velocity less than c. It doesn't agree with your common sense, but it appears to be the way the universe works.
source: http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/ltrans.html#c5


The relative velocity of any two objects never exceeds the velocity of light. Applying the Lorentz transformation to the velocities, expressions are obtained for the relative velocities as seen by the different observers. They are called the Einstein velocity addition relationships.
source: http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/einvel.html#c1


Also, if a spaceship were traveling the speed of light, a motionary observer and a ship that was fallowing it albeit slower than it would see it at the exact same places at the exact same times, fallowing the theory that lightspeed doesn't owe to the velocity of the object it reflects off of. This too fallows the Einstein theory. Wouldn't this mean that light can travel two speeds at once? I just find this all absurd.
I don't quite understand what you're trying to ask here. If you want answers, please clarify this question and I'll try to answer.

cool link:
http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

[Zen 2nd]

When we look at our Sun it is actually in the past. It takes approx 9 minutes for the rays of the Sun to reach Earth.

Also I wouldn't worry about meeting yourself in the future if you were to travel into the future as your future self would have gone into the future in the past.

Plus does that mean that a million of yourself exist because you can pick any time to travel to in the future so for every second that moment is replayed in the past, so to speak.

Does that mean we have no choice in our decisions that everything that happens was supposed to happen?

[Dragoon777]

You know, I'm not sure, I think, that what happens, happens, so if you accidently caused a time paradox, impossible to fix it because what happens, happens, traveling through time, only in space, I agree, but ending up on a different side, I disagree, and if they culd travel forward, but could not travel back, no one would do it.

[Barrage]

reviving old thread dragoon? Time travel to the future has been proven, traveling back in time has been shown to be possible IF the universe was spinning. Of course the universe is not spinning.

[Nightboomfer]

lol, in the movie Napolean Dynamite, they buy a time machine off e-bay or something and it is this ridiculous thing that obviously doesnt work. I dont think it is possible to travel through time, what a ridiculous thought
It's just a jump to the left
(and a step to the riiiiiiiight)
Put your hands on your hips
(lock your knees in tight!)
But it's the pelvic thrust that really drives you insane.

[Dragoon777]

reviving old thread dragoon? Time travel to the future has been proven, traveling back in time has been shown to be possible IF the universe was spinning. Of course the universe is not spinning.

Why does everyone think I am reviving old threads, I have no idea about this, I just see it and write what I think, jees, I mean come on, I'm a Poser I don't even now how to change the color of my letters.

[Barrage]

Because you are^^ I mean common, this thread is about to be 3 years old!

[UnholyKnight]

Time isn't tangible, it isn't real. Entropy is real, and entropy can be reversed. Ever cleaned your room? There you go, you sent your room "back in time".

The only true way to travel back in time would be to reverse the entropy in everything that exists everywhere, taking it back to a "less disorderly" state. And then you haven't really traveled in time because you can't raise the dead, make people younger, or control cosmic events.

Sorry.


Applying the Lorentz transformation to the velocities, expressions are obtained for the relative velocities as seen by the different observers.I always feel bad about not fully comprehending this topic. My great grandfather is the man behind the Lorentz theory and transformation and was a mentor to Einstein as well as a Physics Nobel Prize winner. I'm not the brightest when it comes to physics, Chemistry is more to my liking.

Didn't look at dates, go me for quoting and responding to 2+ year old material.

[blackcrow]

in the simple truth, people shat their pants when they saw a lightbulb I'm sure of it, people will shate their pants when they see a time travel machine.

It can happen, I think it will happen if we can survive that long. I'm more interested in the galaxies and moving forward,

we learn from the past or at least we should to make the future better- we'd be pretty selfish to try and fix our mistakes then try to take responsibility. Maybe some situations deserve to be fixed such as the holocaust, who knows what those people could have become had they been able to live.

[spazmaster666]

A more important question would be once you've traveled back in time (assuming this is possible that is) how would you then return to the exact instance in time from which you left?

[Proud2bme]

In my eyes, a paradox from going to the past would be impossible. If you go back in time to talk to yourself, and you don't remember talking to yourself, then obviously you never managed to talk to yourself. Something will get in the way. You won't manage. Because at that point of time in the past, if you went there and were still perfectly all right and remember things being alright, then things must have gone alright in the past, which is where you are. Past is written in stone in my eyes, the future however...I'm not quite sure about that.

[Gamma]

It's called ka, my little darlings. Learn it, live it, get used to it.

[Nje789]

"iz time travel possible?"

well, let's take a hypothetical situation- you fall on your ass and have to suffer recovering a broken bone. You later use a time machine to prevent this little travesty. You stop your past self from falling, then go back to the time where you left off.

Since you stopped yourself from falling, you never went back in time because you had no reason to.

Well, whether you do, or do not, decide to go back in time to make sure you always warn yourself, you basically end up with a time period where there's two of you, even if there's NEVER a period of time you'd normally exist in where there's NONE of you- you essentially created an extra you.

So, if a time machine can be created, you can also use it to create an infinite amount of anything: you, me, gold, soldiers, anything you can send through time.

..ah, you know what, this is getting complex, and I really don't care about it because I don't think it's possible, so I'm just going to leave the gaps here wide open.

[Koga OR Kouga]

Time travel not possible this is my reason that time travel is impossible because grandfather paradox if you go back in the past and kill your grandfather your dad will never be born so you will never be born to so you cannot go back in the past two kill your grandfather in the first place so that my reason time travel is impossible because if people did time travel you will see Time Traveler on vacation I would like to know what people think about my theory. Thanks for reading my post.