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Can we travel in past in 4rth dimension because according to physics it is not possible to travel in past in even 4rth dimension we can only go in future.pls explain.

Qmechanic
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Muhammad Umer
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1 Answers1

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It seems you are using some Hollywood physics here. There is not a 4th spatial dimension in physics. Spacetime is four-dimensional, but it there is no defined "4th dimension" in which you can travel, as if it were some kind of secret passage. As is, physics do NOT permit travel to past in any way. However due to relativity, it is possible to "travel to the future".

When you are traveling at very high velocities, time moves slower for you than for those who are not. Thus, if you were to travel away from Earth at a speed that is close to the speed of light for some time, and then return from Earth, you would find that more time has passed here than in your frame of reference, thus you would have "traveled in time".

I recommend you to study some Special relativity if this topic interests you, but remember that that 4th dimension time traveling thing is mainly Hollywood physics, not real physics

Nick Heumann
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  • Every physicist that I have learned from or worked with was perfectly comfortable saying that time is the fourth dimension. It is very difficult for me to understand how you can look at the Minkowski metric and say that it is not. – G. Smith Jun 25 '19 at 20:56
  • The thing is that there is a difference between what physicists understand when saying "time is the fourth dimension", and what non-physicists understand. While the Minkowski diagrams and the Tensors used in General Relativity are all four dimensional, yes, I'm afraid that people who are not versed in Relativity may interpret fourth dimension as what is shown inside the black hole from Interstellar, for example. – Nick Heumann Jun 25 '19 at 21:03
  • You made a blanket statement, “There is no ‘4th dimension’ in physics.” As far as I am concerned, it is simply false. – G. Smith Jun 25 '19 at 21:04
  • I believe that I phrased it wrong, for I meant that there is no 4th spatial dimension, which I think is what OP was getting at. We may treat spacetime as four dimensional, but our space isn't. Considering OP's question, "Can we travel in fourth dimension?", I think that it is okay to state that there is no fourth dimension to travel in, as it is spatial dimensions we are are referring to.I made sure to edit the answer to clarify. – Nick Heumann Jun 25 '19 at 21:10
  • @G.Smith, not only is there no "4th dimension," There is no 1st, 2nd, or 3rd dimension either. The dimension of a vector space is the minimum number of vectors needed to span the space. If we wish to represent the locations of physical objects, we can use a three-dimensional vector space to do that, but the space doesn't have three dimensions: It has "dimension equals 3." If you define a coordinate system on that space, then your coordinate system will have three axes, but an axis is not a dimension. – Solomon Slow Jun 25 '19 at 21:17
  • @SolomonSlow I’m guessing that your training was more in math more than physics. Not that there is anything wrong with that. But you don’t seem comfortable with language that all physicists in my experience are perfectly comfortable with. – G. Smith Jun 25 '19 at 21:22
  • @G.Smith, OK, so if physical space has three dimensions, how do you tell them apart? Which dimension is which? Do they have names? – Solomon Slow Jun 25 '19 at 21:24
  • No, of course not. But we can distinguish “the spatial dimensions” from “the time dimension”, at least in any inertial frame. – G. Smith Jun 25 '19 at 21:25
  • @G.Smith, I would call that, "the time axis." And the reason you can distinguish it from the "spatial axes" is that you chose a coordinate system that was convenient for modeling a particular problem, and part of what made it convenient was having one of the axes represent pure time. – Solomon Slow Jun 25 '19 at 21:29
  • Q: Which eminent physicist wrote “Why do we see only three space dimensions and one time dimension?” A: Hawking. I could probably find hundreds more similar quotes, but I have made my point and will not argue for it further. – G. Smith Jun 25 '19 at 21:35
  • "An electron cloud containing only one electron exists in 3 dimensions. All other electron clouds contain more than 1 electron and therefore exist in more than 3 dimensions. The nucleus of the carbon atom, for example, with its 6 electrons, is surrounded by an electron cloud with 18 dimensions. Uranium, with 92 electrons, has an electron cloud of 276 dimensions," - Gary Zukav – Michael Walsby Jun 26 '19 at 10:34