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Time Machine Getting Closer to Reality? Wednesday, August 29, 2007 - Avner Yanai Home >> News >> Physics   
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Possibly the first practical model of a time machine proposed by Professor Amos Ori from the Technion Israel Institute of Technology, may prove to be the first step towards a construction of a mechanism that will allow time travel into the past.
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One of the claims against the possibility of building a time machine is that a negative density material was needed for the creation of the machine. However, Professor Ori proposed a model in which such material is not needed. The time machine is actually only made of vacuum and dust! (One should keep in made that the terminology "machine" might be misleading, as there is no machinery involved in this model. It is actually a theoretical configuration of space-time that could allow travel back in time). According to the model, traveling back in time may only be accomplished to a point in time which is later than the construction of the machine. In other words, if we were able to prepare such a space-time curvature mechanism today, our future selves wouldn't be able to go back and visit the dinosaurs, kill Hitler or stop 9/11. However, even this restriction doesn't prevent many of the philosophical difficulties associated with time travel. The grandfather paradox is probably the most famous problem associated with the possibility of traveling into the past. The paradox, first suggested by the science fiction writer René Barjavel in "The Imprudent Traveler", published in 1943, describes a situation where a man travels back in time and kills his grandfather before his grandfather meets his grandmother. With his grandparents not having the chance to meet, one of the man's parents would have never been born and by extension, the same it true about the man himself. However, if this man would have never been born, he couldn't possibly go back in time and kill his grandfather – hence the paradox. One of the options suggested in philosophical literature to solve this paradox is known as the parallel universes theory, where killing the grandfather actually creates a new parallel universe living the original timeline intact in a sense. Although philosophers continue to argue about backwards time travel and its problems, it is work such as that done by Professor Ori which may finally allow us to realize the possibility of time travel (if indeed it is possible). More information about the model can be found at the Technion's press release and in a paper published in Physical Review D (Abstacat). |
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| What is it that one would be traveling to? The "past"? Is there a past to travel to? Or is the past a projection of our own thinking? | |||
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According to what is said you will actually be going into the past (if you can ever build a real time machine that a human can use). Many often explain general relativity as if past present and future all "exist at the same time" - this isn't easy to grasp and this also does not solve the grandfather paradox. |
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| What is "the past"? | |||
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| I guess that the question you just wrote is now in the past, but again general relativity might be interpreted a bit differently on this issue as you might say that past present and future all "co-exist". | |||
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At any time we can think of the past or present or future. Such thought, like any other thought, coexists with all other thoughts. But why believe that thoughts can be "traveled" to? |
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Do you believe that there are only thoughts? no external reality? or alternatively that all that is accessible to us is our thoughts? but then you need to ask your self how does the REAL physical reality effects us - and what happen if we can go back in time. b.t.w. an interesting experiment a few years back showed that it is possible for people to slow down their own personal passage of time in specific situations - however unless you believe that your own thoughts is all that exists (solipsism) this does not have any effect on the rest of us. |
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\"Do you believe that there are only thoughts?\" I don\'t understand how you came to this assumption. I\'m simply saying that the past is thought. Nothing more. To believe that there is a past that one can \"go to\" is non-sensical. |
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I agree that it is hard to grasp the idea that past, present and future coexist but if the past does not exist how can there be solutions to GR that allows going into it? Here is two good points to start reading more about all of this: http://en.wikipedia.org/wiki/Time_travel http://plato.stanford .edu/entries/time-travel-phys/ |
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"I agree that it is hard to grasp the idea that past, present and future coexist but if the past does not exist how can there be solutions to GR that allows going into it?" It's not hard at all if you accept the belief that time is a container. I don't though. |
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I see. I find it rather silly to have this interesting discussion on our somewhat restricting article comment mechanism. In a few days we are going to add our new forums where such a discussion will be much more fitting I believe. |
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| Consider: If the future is existent so the past. just change the arrow of how the things occur. If the ash of burning tree can return to be tree again you return to the past | |||
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They'd be able to tell upon completion if it worked, as someone from the future would pop out (due to the initial time line having had no-one pop out and by proxy the scientists send some one back at a later time); however, a reverse grandfather paradox arrives, if the initial sendback kills themselves upon their return, or simply deters the initial return within that new time line. The only way for this to work, would be for the sendback to not come in contact with anyone or anything involved with the decision making process regarding their jump. That, or else, upon immediate return, their time of departure is recorded and scheduled for that time line's original individual. Sending back the original sendback would cause a timeloop-paradox in which the original person would exist permanently within the same loop of time and have no progressive time until they sent back the unsent individual of themselves. There shouldn't be any issue with two of the same person contacting or touching. |
