Do You Think Time Travelling Will Ever Be Possible?

[T X 0]

Time traveling is a completely absurd idea, and it's only one more thing scientists (if they accomplish it) will do to destroy the world. Knowing stuff is fine, but knowing too much will lead to the end of the world. Read The Lost Symbol by Dan Brown, seriously, just do it. It explains everything for me. Say we do accomplish time traveling for real, not time manipulation as shadowx said, what would happen? We would become to curious and end up wondering, hmm? What will happen if we go back to the Jurassic period? Then we will create a rip in the fabric of time and destroy time itself. CURIOSITY KILLED THE *BLEEP*ING CAT!

[linekill 1]

I'm a fan of Dr. Michio Kaku because he's a genius yet he has the power to turn complicated ideas like time traveling into something for the mass to understand. I'm no genius so I keep on reading his blog to learn those complicated theoritical physics problems/discussions, etc.

As for time travel, here's how he discusses it.

However, rather remarkable advances in quantum gravity are reviving the theory; it has now become fair game for theoretical physicists writing in the pages of Physical Review magazine. 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, i.e. what happens when you go back in time and kill your parents before you are born? Question: if your parents died before you were born, then how could you have been born to kill them in the first place?
There is also the paradox of the man with no past. For example, lets 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. Question: where did the idea of the time machine come from?

There is also the paradox of the man who is own mother (my apologies to Heinlein.) Jane is left at an orphanage as a foundling. When Jane is a teenager, she falls in love with a drifter, who abandons her but leaves her pregnant. Then disaster strikes. She almost dies giving birth to a baby girl, who is then mysteriously kidnapped. The doctors find that Jane is bleeding badly, but, oddly enough, has both sex organs. So, to save her life, the doctors convert Jane to Jim.

Jim subsequently becomes a roaring drunk, until he meets a friendly bartender (actually a time traveler in disguise) who wisks Jim back way into the past. Jim meets a beautiful teenage girl, accidentally gets her pregnant with a baby girl. Out of guilt, he kidnaps the baby girl and drops her off at the orphanage. Later, Jim joins the time travelers corps, leads a distinguished life, and has one last dream: to disguise himself as a bartender to meet a certain drunk named Jim in the past. Question: who is Janes mother, father, brother, sister, grand- father, grandmother, and grandchild?

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. 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 distant drummer.

However, before Einstein died, he was faced with an embarrassing problem. Einsteins neighbor at Princeton, Kurt Goedel, perhaps the greatest mathematical logician of the past 500 years, found a new solution to Einsteins own equations which allowed for time travel! The river of time now had whirlpools in which time could wrap itself into a circle. Goedels solution was quite ingenious: it postulated a universe filled with a rotating fluid. Anyone walking along the direction of rotation would find themselves back at the starting point, but backwards in time!

In his memoirs, Einstein wrote that he was disturbed that his equations contained solutions that allowed for time travel. But he finally concluded: the universe does not rotate, it ex- pands (i.e. as in the Big Bang theory) and hence Goedels solution could be thrown out for physical reasons. (Apparently, if the Big Bang was rotating, then time travel would be possible throughout the universe!)

Then in 1963, Roy Kerr, a New Zealand mathematician, found a solution of Einsteins 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. The ring, in turn, acts like the Looking Glass of Alice. 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 Einsteins 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.

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. 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, Schrodingers 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 ELSEs past by saving, say, 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. 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 Englands future? No. 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 amounts of energy. One either has to harness the power of a star, or to find something called exotic matter (which falls up, rather than down) or find a source of negative energy. (Physicists once thought that negative energy was impossible. But tiny amounts of negative energy have been experimentally verified for something called the Casimir effect, i.e. the energy created by two parallel plates). All of these are exceedingly difficult to obtain in large quantities, at least for several more centuries!

Then there is the problem of stability. The Kerr black hole, for example, may be unstable if one falls through it. Similarly, quantum effects may build up and destroy the wormhole before you enter it. Unfortunately, our mathematics is not powerful enough to answer the question of stability because you need a theory of everything which combines both quantum forces and gravity. At present, superstring theory is the leading candidate for such a theory (in fact, it is the ONLY candidate; it really has no rivals at all). But superstring theory, which happens to be my specialty, is still to difficult to solve completely. The theory is well-defined, but no one on earth is smart enough to solve it.

Interestingly enough, Stephen Hawking once opposed the idea of time travel. He even claimed he had empirical evidence against it. If time travel existed, he said, then we would have been visited by tourists from the future. Since we see no tourists from the future, ergo: time travel is not possible. Because of the enormous amount of work done by theoretical physicists within the last 5 years or so, Hawking has since changed his mind, and now believes that time travel is possible (although not necessarily practical). (Furthermore, perhaps we are simply not very interesting to these tourists from the future. Anyone who can harness the power of a star would consider us to be very primitive. Imagine your friends coming across an ant hill. Would they bend down to the ants and give them trinkets, books, medicine, and power? Or would some of your friends have the strange urge to step on a few of them?)

In conclusion, dont turn someone away who knocks at your door one day and claims to be your future great-great-great grandchild. They may be right

Source: http://mkaku.org/home/articles/the-physics-of-time-travel/

[Baniboy 3]

Time traveling is a completely absurd idea, and it's only one more thing scientists (if they accomplish it) will do to destroy the world. Knowing stuff is fine, but knowing too much will lead to the end of the world. Read The Lost Symbol by Dan Brown, seriously, just do it. It explains everything for me. Say we do accomplish time traveling for real, not time manipulation as shadowx said, what would happen? We would become to curious and end up wondering, hmm? What will happen if we go back to the Jurassic period? Then we will create a rip in the fabric of time and destroy time itself. CURIOSITY KILLED THE *BLEEP*ING CAT!

Calm down. A, you can't mess up the time continuum, that's why it's called a continuum. B, read some actual scientific books and not some pseudo-named books that explain nothing about everything, read real science instead and learn how to interpret it. Edited March 28, 2010 by Baniboy (see edit history)

[Бојан 0]

Why not? Einstein was pretty close finding the time traveling receipt or maybe he founded and he is traveling?

[Rael IAK 0]

Technically, the question which forms the title of this topic doesn't make much sense. It's sort of like asking "Do you think gravity will ever be possible?". It depends on exactly what you consider an acceptable definition of time traveling.

 

If I

 

1) Get into a spaceship and travel towards somewhere off in the galaxy in a straight line at 99% of the speed of light on Aug 1, 2010

 

2) Travel for a year and turn around and come back to Earth at the same speed

 

3) I will NOT find that I arrive on Earth on Aug 1, 2012.

 

It will be September 27, 2024 on Earth. I will have aged 2 years since I left. The Earth and everything on it will have aged 14.16 years. If you think that qualifies as traveling into the future then time travel goes on around us all the time (although only to an appreciable degree to VERY small things).

 

You can adjust the amount of the discrepancy in the passage of time by increasing or decreasing your speed and the length of your trip (how long you figure your trip to take). The math is actually not that hard. Anyone who owns a calculator and can manage high school algebra can do it.

 

This is a consequence of the Special Theory of Relativity which has been around a little over 100 years. The only thing stopping man from doing it is the engineering hurdles in making a ship that can go fast enough. It basically stems from the fact that time does not "go on" at a constant rate throughout the universe. Time passes more slowly for an object that is moving relative to another object. Special Relativity says that the ONLY thing that is constant no matter "what" is moving around "where" is the speed of light.

 

Ok, I'm a biologist by education, not a physicist. I have an interest in relativity and quantum physics so I learned something about them but I'm certainly not an authority. Having said that, Special Relativity has been a generally accepted theory for decades. There is a ton of evidence to support it. To my knowledge, Einstein's version of General Relativity is NOT generally accepted. There is/was some debate as to whether the universe is best described using 13 or 27 dimensions or something.

 

Special Relativity says nothing can move faster than the speed of light. Special Relativity "sort of" allows us to travel into the future as described above. It does NOT allow traveling into the past so don't freak over the Jurassic Park scenario, lol.

 

If this qualifies as "time traveling" then, yes, it's not only possible but sub-atomic particles have been doing it for billions of years

[dasmeaty 0]

The way I see it. Time is a measurement we give to measure the space between events, once these events have happened they have happened and their is no such thing as a timeline (So there is no specific record of what has been for us to travel back into and no set path for events to lead into) there is only the results of these effects, there are of course theories that there are many repeating universes each similar to the last, and other theories that if you did not witness something then all the possible outcomes occured at the same time (So by shooting a cat in the pitch black, the cat both dies and dodges the bullet until you see it is dead, however in an alternate universe the cat is alive when you turn the light on).If the first theory is true then maybe many millions of years from now we will travel into these alternate universes and witness copies of events that happened previously in our own (Not true time travel), or if the second is true then the cat will have done many things in the pitch black one of them being travelling in time to every point in history.Personally I see this as physics mumbo jumbo to help explain something that can't be proved, as to prove the cat theory is to disprove it at the same time (You must remain unaware of the cat at the point of time).Do I think time travel is possible? No.