What would 3d of time and 1d of space be like?

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What would 3d of time and 1d of space be like?

Postby tj444 on September 21st, 2017, 2:21 am 

I am having trouble imaging a universe where 3 dimensions of time and 1 dimension of space would be like can someone help? Also might expand the question to 2 dimensions of time and 2 dimensions of space? Can a universe exists as stated above?

I also have few other questions if I have to many questions just tell me and I will start in another thread.

Can anything exist below 2 dimensions. I hear a lot about string theory and how a string is one dimension.
Lets say someone claimed to find a string how would someone know the string is 1 dimensional?

My next question is can light be less than 3 dimensions not counting the time dimensions.

How would light behave if it could only move in one direction but experiences 3 dimensions of time? Or 2 dimensions of time and 2 dimensions of space? Lets assume things with greater mass experience the 3 dimensions of space 1 dimension of time.
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Re: What would 3d of time and 1d of space be like?

Postby bangstrom on September 21st, 2017, 4:20 am 

tj444 » September 21st, 2017, 1:21 am wrote:I am having trouble imaging a universe where 3 dimensions of time and 1 dimension of space would be like can someone help?


I have no idea how to imagine those dimensions either. The usual visualization is one of 3 dimensions of space and one of time. Height, Width, Depth, and Duration.

The primer on imagining lower and higher dimensions is the book “FLATLAND” A Romance of Many Dimensions." This is an old classic by Edwin Abbott who also wrote the Alice Books under the name of Lewis Carroll. The book is still in print and easy to find.
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Re: What would 3d of time and 1d of space be like?

Postby mitchellmckain on September 21st, 2017, 2:31 pm 

First you need to explain what you mean when you decide to label a dimension as time rather than space. Are you referring to a mathematical difference, or some less well defined philosophical or experiential difference?

Mathematically The difference is the sign in the metric
ds2 = dx2+dy2+dz2-dt2
But such differences in sign tend to be relative and thus switching around the sign would probably make no difference.

Thus you might change the question to something much much more simple like this...
What if we had more than one time dimension?
ds2 = dx2+dy2+dz2-dt2-du2
A universe with more than one kind of time suggests we might be able to control our direction on the temporal plain and that would mean that we might have devices like a watch to stop the time for everyone else so we can finish projects in no time at all with respect to others -- though when you think about it, you would probably need a much larger device to change the direction of time flow in a region of space like a chamber. It thus might be a universe without many of the same time constraints as we have in this one. Though... it would also mean that many people might be live their whole lives in a very short period of time with respect to others.

And then... this suggests another interesting question. How do we know there isn't another time dimension like this? Maybe there is and such devices are possible. Sounds like the basis for a science fiction novel or movie.

Another question for this universe might be... what are the effects of a separation in that other time dimension? This could give you the conflict element in your science fiction story. Perhaps you find that such a separation means you are living in a world with an alternate history, and in your story people using the time device find themselves lost in another world.

If we imagine a world where changing directions on the temporal plain didn't require some fancy device but that there are objects and organisms which do this in nature. We would observe processes happening at a different rate than what our usual 3-1 space time science predicts. If the differences were small then these observations would probably just give us the science we need to make devices for controlling it. If it were not so subtle then our science would not work -- at least not in places or on things which were moving on a very different temporal vector than we do.
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Re: What would 3d of time and 1d of space be like?

Postby tj444 on September 21st, 2017, 11:04 pm 

Mathematically you mention "sign in the metric is the only differences." So does changing sign the sign in the metric make any differences? When you mention sign in the metric I assume you are just referring to a + becomes a - or vice versa? Also are any other possible ways to mathematically express dimensions where changing the dimensions from 3 time dimensions to 1 space dimensions make a huge difference?



To explain what I mean by the time dimension I think of a 7 or 6 dimensional universe. You take those 3 or 2 dimensions and you add it to light. But you minus the 3 space dimensions up, down, left and right or you minus up and down and add the last 3 or 2 dimensions from the 7 or 6 dimensional universe to add up to 4.
So I am not referring to a 7 or 6 dimensional universe I am referring to a 4 dimensional universe that experiences different dimensions. I am not sure if this makes a difference compared to just going with the usual 4 dimensions.

This brings up another topic. Is it possible light could have less than 4 dimensions or more and non quantum objects have 4 dimensions? Just to let you know the math is above my head but I want to know if the math is possible and how would someone test the ideas above? Has someone ever tested the concepts?


The reason I am asking this is because string theory needs a bunch of dimensions but it would be cool if certain parts like light added up to 4 dimensions or if there were more or less dimensions but only certain parts such as light experience these greater or lower dimensions. Maybe this is a better explanation of quantum mechanics.

Also I was reading about light and how a photon experiences all its existence at once and this got me thinking maybe light doesn't experience reality the same as other stuff. I am not sure existence is the correct term.
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Re: What would 3d of time and 1d of space be like?

Postby mitchellmckain on September 22nd, 2017, 2:03 am 

tj444 » September 21st, 2017, 10:04 pm wrote:Mathematically you mention "sign in the metric is the only differences." So does changing sign the sign in the metric make any differences? When you mention sign in the metric I assume you are just referring to a + becomes a - or vice versa? Also are any other possible ways to mathematically express dimensions where changing the dimensions from 3 time dimensions to 1 space dimensions make a huge difference?

It has been noted by physicists that most of the mathematical laws don't treat time as special, not in the way we think during the living our lives. From special relativity we have learned to treat time and space as elements of a four vector and thus to formulate the laws of nature in a way that do not distinguish time from space. There is just that one difference of sign in the metric. The point is, that although much of physics you learn in textbooks does treat space and time quite differently, a lot of it is probably just our own prejudice, and relativity shows us that we really don't have to and probably shouldn't.

A related question is the arrow of time, because that is another stark difference between our experience of time and the role in plays in the mathematical laws of nature. We see the past and future as fundamentally different, but most of the mathematical laws do not. For most of them, they look pretty much the same either forwards or backwards in time. So while there are a couple things which do distinguish them, most don't. I will leave this as a side issue which you can explore if you want to.

tj444 » September 21st, 2017, 10:04 pm wrote:To explain what I mean by the time dimension I think of a 7 or 6 dimensional universe. You take those 3 or 2 dimensions and you add it to light. But you minus the 3 space dimensions up, down, left and right or you minus up and down and add the last 3 or 2 dimensions from the 7 or 6 dimensional universe to add up to 4.
So I am not referring to a 7 or 6 dimensional universe I am referring to a 4 dimensional universe that experiences different dimensions. I am not sure if this makes a difference compared to just going with the usual 4 dimensions.

I do not understand your meaning when you say, "and you add it to light."
Furthermore you have not addressed the real question I had because you didn't explain how adding a time dimension is different from adding a space dimension.

I explained the idea in my example by the sign of the metric and by adding another degree of freedom in our "motion" through time.

tj444 » September 21st, 2017, 10:04 pm wrote:This brings up another topic. Is it possible light could have less than 4 dimensions or more and non quantum objects have 4 dimensions?

I don't know what this possibility you suggest is referring to. Light has dimensions?

tj444 » September 21st, 2017, 10:04 pm wrote: Just to let you know the math is above my head but I want to know if the math is possible and how would someone test the ideas above? Has someone ever tested the concepts?

No scientists do not pick a random number of space and time dimensions. When they explore the possibilities of other numbers of dimensions there is usually a reason for it. For example, they might explore various physical laws in 2 dimensions because there are variety of situations (like in crystals) where things might be restricted to 2 dimensions.

tj444 » September 21st, 2017, 10:04 pm wrote:The reason I am asking this is because string theory needs a bunch of dimensions but it would be cool if certain parts like light added up to 4 dimensions or if there were more or less dimensions but only certain parts such as light experience these greater or lower dimensions. Maybe this is a better explanation of quantum mechanics.

Once again I don't understand this talk of light having or adding up to a number of dimensions.

Many physicists have struggled to find an alternative to quantum mechanics. I prefer to accept the experimental results. That is what honest scientific inquiry should do.

tj444 » September 21st, 2017, 10:04 pm wrote:Also I was reading about light and how a photon experiences all its existence at once and this got me thinking maybe light doesn't experience reality the same as other stuff. I am not sure existence is the correct term.

I think this whole idea of anthropomorphizing light and talking about what it "experiences" is all on very very shaky ground. I seriously doubt whether it means anything whatsoever.
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Re: What would 3d of time and 1d of space be like?

Postby tj444 on September 29th, 2017, 10:33 pm 

Thanks for the response. I don't really have any more questions at this time on this topic.
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Re: What would 3d of time and 1d of space be like?

Postby hyksos on September 30th, 2017, 1:13 am 

There is one place in Einstein's equations where there is a minus sign. It is the only way in which time and space enter differently, and nonetheless, the result of that is that they feel completely different from one another. Space just feels like this place where you can go at will wherever I want in , whereas time feels as we know, like a one-way street.

If there were no minus sign, life as we know it, would be completely different. We would probably not feel that things were happening. In fact, we would prove mathematically that there would be no point in having a brain even, because you wouldn't be able to predict things.

We have brains because from observing what we see in one part of spacetime , we can calculate what is in another part of spacetime in our future, and that's useful. If it weren't for that minus sign, we couldn't do that. Where I know what's happening over here, and I predict what is happening over at Harvard. It's not going to work. It all has to do with that minus sign.


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