Is time travel possible?

[abhinavkumar_iitr05]

There is always a conflict between whether we can travel in time?I just want to know whether it would be ever possible experimentally or it will only remain theoritical?Just give comments on the topic with reason.<br /><br />Thanks

 

[vogon13]

If everyone could travel back in time and change things to their own liking (and there might be universes where this can happen) the result would be Chaos.<br /><br />And this is no ordinary Chaos, this would be Chaos of a sort that would destroy the universe in which it could occur.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[abhinavkumar_iitr05]

Does this is the only reason that we negate the time travel?Does science depends on the results?Was the result of the atom bomb doesn't cause havoc?So is it right to negate time travel only because of this chaos only?

 

[thalion]

I think it was Hawking (?) who said that the surest evidence that there will never be time travel is that we're not inundated by tourists from the future.<br /><br />However, I've seen a possible counterargument to that. There are a lot of people who think that it would be impossible for any time machine to permit travel back to a time before the machine was created. In that case, perhaps the reason that there aren't any tourists from the future is simply because the time machine hasn't been invented yet. <img src="/images/icons/wink.gif" />

 

[alkalin]

Nah.<br /><br />Time is not a variable as some kinds of math might suggest. It is now, throughout the universe. It is only signal or information transfer of events that are delayed; giving the impression that time is different in other places. You cannot travel somewhere in time different than here because such does not exist. But the mind is good at looking into the past (history) and the future (projection). What a gift? Do not confuse this mind activity with time travel literally.<br />

 

[hungrrrry1]

I would have to say that I believe it can be done...but like mentioned, travelling at light speed only allows forward travel of time...and we can't do that yet...Time warp and wormhole theories abound and I wouldn't rule them out...maybe there is something about time travel and blackholes that is almost impossible to experiment with without fatal risks, not to mention speed of light travel to this blackhole...However, when you read or hear of comments saying we haven't been visited by tourist from the future, maybe there is good reason...Thousands of stories of UFO sightings have to account for something and myself, I am not so sure we are being visited by aliens but maybe these things are ourselves from the future obeying a strict code of not disrupting history. Yes witnesses see the craft etc., butthere are never confirmations of these happening and maybe the government does know something about that and doesn't want this ability in the hands of nut-cases, like George Bush for instance! <img src="/images/icons/smile.gif" />

 

[ihwip]

I spent plenty of time pondering this question. Travelling forward in time is no problem. Find yourself a nice blackhole, park in a safe orbit for a couple years, come back and viola! millions of years in the future.<br /><br />Travelling into the past is logically possible in my opinion. The reason it wouldn't cause complete chaos as above is that the very act of time travel would shift you into a new universe. If you were to travel to 1000AD, the butterfly effect would rob you of our known future (1001AD-present) and replace it with a brand new one.<br /><br />The actually physical requirements of time travel are pretty much impossible though. Breaking the law of creation/destruction of matter for one.<br /><br />Not only that but unless you find a way to travel 5th dimensionally, you are stuck in said universe, even if you go forward in time again. You would never be able to go back to the place you once were.<br /><br />This is my own personal theory, I know alot of others in these forums disagree but hey.

 

[siarad]

<blockquote><font class="small">In reply to:</font><hr /><p>Doing this you delay your own time.<p><hr /></p></p></blockquote><br />Surely you're delaying your own death but increasing your time.<br />SatNav satellites gain 38 microseconds a day

 

[mythrz]

Well, I know for a fact that it isn't and wouldn't be possible in my lifetime to travel in the past. Why? Because, I would come back and tell myself if it was possible. I would save myself all the nights I debated with myself whether or not time travel is possible.

 

[abhinavkumar_iitr05]

OK its right that there is no one from the future here.But is this can't be taken in some other way that it is <br /><br />actually the invisibility of them that it seems that they r not here.Nature can take this step to protect the chaos <br /><br />which is likely to be created by the time travel.It would have provided the time travel by doesn't allowed the <br /><br />change in the past i.e. it has not given us the power to move in time physically but mentally so that we can't <br /><br />affect the past.This can also be thought.Am I not correct?

 

[qso1]

hungrrrry1<br />maybe these things are ourselves from the future obeying a strict code of not disrupting history.<br /><br />My response:<br />And when will humanity start actually obeying a strict code of any kind? If time travel is possible, surely we would have seen criminals from tomorrow by now. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[newtonian]

abhinavkumar_iitr05 - Forward time travel is possible at various rates.<br /><br />Backward time travel is not possible - this is how our unvierse, and apparently all universes, have been created.<br /><br />Biblical astronomy helps here, since much of this cannot be observed by mere human scientists.<br /><br />The Bible shows that God's concept of time is drastically different from ours (Psalms 90:4; 2 Peter 3:8) and the latter verse may indicate the reciprical is possible.<br /><br />However, note all the math ratios are positive, not negative. <br /><br />Time's arrow is one way. God is never spoken of as travelling back in time.<br /><br />This is simply one of the properties God created in time, and apparently in all universes.<br /><br />It is also one of the properties, or attributes, of God. The name Jehovah is defined as "He causes to be." <br /><br />This is therefore involving cause and effect, and narrows down the scientific choice of infinite past causes and effects or a first cause.<br /><br />Reverse time travel would, of course, violate cause and effect or causality.<br /><br />

 

[pirx_the_pilot]

Travel to future yes.<br /><br />Travel to past no.

 

[Anonymous]

In H.G. Wells’ novel, THE TIME MACHINE, our protagonist jumped into a special chair with blinking lights, spun a few dials, and found himself catapulted several hundred thousand years into the future, where England has long disappeared and is now inhabited by two groups of strange creatures, the Morlocks and the Eloi.<br /> <br /> That may have made great fiction, but physicists have always scoffed at the idea of time travel, considering it to be the realm of cranks, mystics, and charlatans, and with good reason. However, rather remarkable advances in quantum gravity are reviving the theory; time travel has now become fair game for theoretical physicists writing in the pages of PHYSICAL REVIEW magazine.<br /> <br /> One stubborn problem with time travel is that it is riddled with several types of paradoxes. For example, there is the paradox of the man with no parents: What happens when you go back in time and kill your parents before you are born? If your parents died before you were born, then how could you have been born to kill them in the first place?<br /><br /> There is also the paradox of the man with no past. For example, let’s say that a young inventor is trying futilely to build a time machine in his garage. Suddenly, an elderly man appears from nowhere and gives the youth the secret of building a time machine. The young man then becomes enormously rich playing the stock market, race tracks, and sporting events because he knows the future. Then, as an old man, he decides to make his final trip back to the past and give the secret of time travel to his youthful self. Where did the idea of the time machine come from? <br /> <br /> <div class="Discussion_UserSignature"> <strong><font size="2"><p align="center"><br /><img id="a9529085-d63d-481e-9277-832ea5d58917" src="http://sitelife.space.com/ver1.0/Content/images/store/9/2/a9529085-d63d-481e-9277-832ea5d58917.Large.gif" alt="blog post photo" /><br /><font color="#339966">Oops! this is my alien friend.</font></p><p align="center"><font color="#ff6600">╬→Ť╠╣є ’ M€ ’<br />╬→ Ðôŵņ2Ëãřŧĥ ๑<br />╬→ ЙДm€ :Varsha<br /></font></p></font></strong> </div>

 

[SpeedFreek]

These are commonly debated scenarios <img src="/images/icons/smile.gif" /><br /><br />A lot of scientists in the past have seen the causal paradoxes involved and have thus decided that travelling in time is impossible.<br /><br />It seems that the problems always arise from travelling backwards in time. Travelling forwards causes fewer problems (unless you want to travel back again!).<br /><br />Special Relativity describes a means of travelling forwards in time. You simply need to go on a journey and return at relativistic speed. During that journey you will age slower than the people you left behind. If you leave Earth and travel at 0.999c for around 3 months, when you return 10 years will have passed.<br /><br />But travelling backwards is a different matter and can seem to cause all sorts of paradoxes like the ones you mentioned. Also, we have no current theoretical mechanism for travelling backwards in time, although our research at the quantum level is throwing up some interesting leads.<br /><br />Causal paradoxes like killing your father before you were conceived, or taking an invention backwards in time seem insurmountable at first. If you kill your father before conception, how can history show you were conceived? It seems that either it changes history (i.e. you suddenly weren't conceived, and you immediately disappear in a puff of causal logic!) or an alternative history "time-line" could be formed alongside your own. But this would soon lead to countless timelines sprouting and branching off (in different dimensions?)<br /><br />Then there is the proposition that, if time travel is <i> ever </i> invented and used extensively, it would be apparent throughout history, with timetravellers appearing everywhere, and thus time travel could be said to exist at all points in history!<br /><br />Then again, maybe whenever it is used, a different <i> time-line </i> is formed, which the time travellers own universe can have no knowledge of. So maybe a time traveller can only tra <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>

 

[Aetius]

I don't think that time travel, as often portrayed in science fiction, is possible. At least I hope not.<br /><br />Once sentient beings start altering the past to better suit their liking, the 'Law Of Unintended Consequences' takes over. The future they actually create (with the aid of their time machines) could be even worse than the present they sought to change.<br /><br />Besides, then the Universe would need Time Lords like Doctor Who to keep everything in order. It's just less messy if we're all forced to live in the present moment, and accept the past as unchangeable.<br /><br />As the character Captain Janeway, of the TV series <i>Star Trek: Voyager</i>, once said regarding temporal paradoxes, "The past is the future, the future is the past...the whole thing gives me a headache!" <img src="/images/icons/wink.gif" />

 

[qso1]

Short answer for today based on known technology:<br />No.<br /><br />Could time travel be possible in the future?<br />Possibly yes. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[Anonymous]

Not surprisingly, time travel has always been considered impossible. After all, Newton believed that time was like an arrow; once fired, it soared in a straight, undeviating line. One second on the earth was one second on Mars. Clocks scattered throughout the universe beat at the same rate.<br /> <br /> <br /> Einstein gave us a much more radical picture. According to Einstein, time was more like a river, which meandered around stars and galaxies, speeding up and slowing down as it passed around massive bodies. One second on the earth was NOT one second on Mars. Clocks scattered throughout the universe beat to their own drummer.<br /><br /> However, before Einstein died, he was faced with an embarrassing problem. Einstein’s neighbor at Princeton, Kurt Gödel, perhaps the greatest mathematical logician of the past 500 years, found a new solution to Einstein’s own equations which allowed for time travel!<br /><br /> The “river of time” now had whirlpools in which time could wrap itself into a circle. Gödel’s solution was quite ingenious: It postulated a universe filled with time that flowed like a rotating fluid. Anyone walking along the direction of rotation would find oneself back at the starting point, but backwards in time! <br /><br /> <br />In his memoirs, Einstein wrote that he was disturbed that his equations contained solutions that allowed for time travel. But he finally concluded that the universe does not rotate, it expands (as in the Big Bang theory) and hence Gödel’s solution could be thrown out for “physical reasons.” (Apparently, if the Big Bang was rotating, then time travel would be possible throughout the universe!)<br /> <div class="Discussion_UserSignature"> <strong><font size="2"><p align="center"><br /><img id="a9529085-d63d-481e-9277-832ea5d58917" src="http://sitelife.space.com/ver1.0/Content/images/store/9/2/a9529085-d63d-481e-9277-832ea5d58917.Large.gif" alt="blog post photo" /><br /><font color="#339966">Oops! this is my alien friend.</font></p><p align="center"><font color="#ff6600">╬→Ť╠╣є ’ M€ ’<br />╬→ Ðôŵņ2Ëãřŧĥ ๑<br />╬→ ЙДm€ :Varsha<br /></font></p></font></strong> </div>

 

[Anonymous]

Then in 1963, Roy Kerr, a New Zealand mathematician, found a solution of Einstein’s equations for a rotating black hole, which had bizarre properties. The black hole would not collapse to a point (as previously thought) but into a spinning ring (of neutrons). The ring would be circulating so rapidly that centrifugal force would keep the ring from collapsing under gravity.<br /><br />The ring, in turn, acts like Alice’s Looking Glass. Anyone walking through the ring would not die, but could pass through the ring into an alternate universe. Since then, hundreds of other “wormhole” solutions have been found to Einstein’s equations. These wormholes connect not only two regions of space (hence the name) but also two regions of time as well. In principle, they can be used as time machines.<br /> <br /> <br /> <br /> Recently, attempts to add the quantum theory to gravity (and hence create a “theory of everything”) have given us some insight into the paradox problem.<br /><br /> In the quantum theory, we can have multiple states of any object. For example, an electron can exist simultaneously in different orbits (a fact which is responsible for giving us the laws of chemistry). Similarly, Schrödinger’s famous cat can exist simultaneously in two possible states: dead and alive. So by going back in time and altering the past, we merely create a parallel universe. So we are changing someone ELSE’s past by saving, for example, Abraham Lincoln from being assassinated at the Ford Theater, but our Lincoln is still dead. In this way, the river of time forks into two separate rivers.<br /><br /> <br />But does this mean that we will be able to jump into H.G. Wells’ machine, spin a dial, and soar several hundred thousand years into a future of some England?<br /><br /> No, or at least, not right now. There are a number of difficult hurdles to overcome. First, the main problem is one of energy. In the same way that a car needs gasoline, a time machine needs to have fabulous am <div class="Discussion_UserSignature"> <strong><font size="2"><p align="center"><br /><img id="a9529085-d63d-481e-9277-832ea5d58917" src="http://sitelife.space.com/ver1.0/Content/images/store/9/2/a9529085-d63d-481e-9277-832ea5d58917.Large.gif" alt="blog post photo" /><br /><font color="#339966">Oops! this is my alien friend.</font></p><p align="center"><font color="#ff6600">╬→Ť╠╣є ’ M€ ’<br />╬→ Ðôŵņ2Ëãřŧĥ ๑<br />╬→ ЙДm€ :Varsha<br /></font></p></font></strong> </div>

 

[Aetius]

Thanks! That was very interesting.

 

[qso1]

Cherry2:<br />However, to me, I have still not reached a conclusion wheather Time Travel is Possible.<br /><br />Me:<br />Prior to the statement above, you stated very well where we are at this point in our knowledge of time as theorized by Einstein and others. In the statement above, its not unusual that you have been unable to reach a conclusion. We know that today, just based on our tech level that time travel is currently impossible. There may well be reasons why it may never be possible or we may one day find it is possible.<br /><br />A conclusion is almost impossible to reach. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[metalmind]

I DONT THINK TIME TRAVEL IS POSSIBLE, TO GO FORWARD OR BACKWARDS. ITS LIKE SAYING THIS, IF YOU COULD MAKE THE EARTH STOP, WOULD TIME STOP? NO. THERE WOULD BE NO GRAVITY TO KEEP ANYONE ON IT , BUT TIME WOULD NOT STOP. TURN THE EARTH IN THE OTHER DIRECTION, WOULD TIME GO BACKWARDS. NO, BUT THATS ANOTHER QUESTION. THINK ABOUT THIS. IF THE EARTH WAS SPINNING FASTER, WOULD TIME GO FASTER? NO, BUT THE GRAVITATIONAL PULL WOULD BE GREATER, I WOULD THINK. WITH THE EARTH SPINNING SLOW , WELL , YOU THINK ABOUT WHAT WOULD HAPPEN, LOL. THINK ONE MORE TIME ABOUT THIS ONE . PUT A PENNY ON A TABLE , PUT A PAPER OVER THE PENNY . TAKE A PICTURE OF THE PAPER COVERING THE PENNY. LOOK AT THE PICTURE OF THE PAPER COVERING THE PENNY. IS THE PENNY UNDER THE PAPER IN THE PICTURE? NO, JUST THE PAPER. THINK OF THE PENNY AS TIME TRAVEL, ITS NOT POSSIBLE....... METALMIND

 

[Aetius]

My ears hurt. Please, don't capitalize every word. <img src="/images/icons/wink.gif" />

 

[SpeedFreek]

<font color="yellow"> I don't think time travel is possible, to go forwards or backwards. </font><br /><br />Then you are ignoring what has been established by repeatable scientific experiments. In October of 1971, J. C. Hafele and Richard E. Keating took four cesium-beam atomic clocks aboard commercial airliners and flew twice around the world, first eastward, then westward, and compared the clocks against those of the United States Naval Observatory.<br /><br />According to special relativity, the speed of a clock is greatest according to an observer who is not in motion with respect to the clock. In a frame of reference in which the clock is not at rest, the clock runs slower, and the effect is proportional to the square of the velocity. In a frame of reference at rest with respect to the center of the earth, the clock aboard the plane moving eastward, in the direction of the earth's rotation, is moving faster than a clock that remains on the ground, while the clock aboard the plane moving westward, against the earth's rotation, is moving slower.<br /><br />According to general relativity, another effect comes into play: the slight increase in gravitational potential due to altitude that speeds the clocks back up. Since the aircraft are flying at roughly the same altitude in both directions, this effect is more "constant" between the two clocks, but nevertheless it causes a difference in comparison to the clock on the ground.<br /><br />The published outcome of the 1971 experiment was consistent with special relativity, and the observed time gains and losses were reportedly different from zero to a high degree of confidence. The results were contested by some at the time, but have since been repeately confirmed.<br /><br />One notable approximate repetition of the original experiment took place on the 25th anniversary of the original experiment, using more precise atomic clocks, and the results were verified to a higher degree of accuracy. Nowadays such relativi <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>

 

[oscar1]

"Also, at the quantum level, causality goes out of the window - effects can happen before their causes."<br /><br />Yes, but there is no effect without a cause, even when the cause comes after the effect.