I get the idea of dimensions of reality and how there are eg infinite two dimensional planes in our 3d one. What I don’t get is why they can’t be moved between. In a 3d cube we can draw a 2d line between any two points by changing the direction.
Applying this to reality, if we exist in a universe with more than 3 dimensions, why are we unable to change the “direction” we are in?
I’ve often heard extra dimensions described as planes but why can we not change planes in the same way a diagonal line would. Is it because the concept of a higher dimensional direction doesn’t exist in our lower dimension?
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You got it wrong. When scientists say, “space is 5 dimensional,” they mean that coordinates of an object in the space-time are defined by 5 parameters. And due to spacetime warping you can create such theories with lots of parameters. It doesn’t mean there is some sort of hyperspace outside of our normal 3 dimensions.
I think you’re confusing two different kinds of “dimensions” here. The more scientific definition of dimensions are the 4 dimensions that constitute the 3 cardinal directions plus time (some argue there are more, but that has yet to be supported experimentally).
The other definition you’re using for dimensions is the concept of separate realities that is popular in science fiction writings, for example, rick and morty traveling to parallel universes.
For the more scientific one, you can’t move “out” of the 4 dimensions but you can (and do) certainly move within any 4 of the dimensions in any way you want (except backwards through time, for reasons too advanced for this thread). You can’t leave these dimensions because they make up everything, and you can’t exist within nothing. Also, as I hinted at above, it’s possible that there are more than 4 dimensions in our universe but no one has created any sort of experiment to test whether or not they actually exist. However, *if* they exist, the same logic applies, and you can and do move through those dimensions. That said *if* they exist these dimensions are very *small* and are not noticeable by us.
The other kind of dimension, the parallel universe kind, are scientifically speaking completely different. This is another case of unsupported hypotheses, but *if* parallel universes exist, there’s no known way of traveling to and from them, and speculated on why not or how to do so is a exercise in futility.
Draw a line on a sheet of paper.
Why can’t you lift the line up into a third dimension?
How do you know we don’t? It’s our perception that is locked to four dimensions. Since we are only able to perceive in four dimensions, any action in additional dimensions is mapped to those four in our perception— we only see a slice of it.
So if you’re wondering why we can’t change our direction in time, that would be because we don’t know how to perceive that change, and we can’t visualize the next dimension out.
And any changes we make in spacetime still need to adhere to the laws of physics.
>I’ve often heard extra dimensions described as planes
Those physics theories that hypothesize the existence of more dimensions usually need a mechanism that hides them from us. For example they can be “folded”, wich basically means you can’t move more than a microscopic bit into that 4th+ direction before reaching the end of it.
We are very far away from confirming any of those theories though. It’s just an idea of many that could solve some difficult physics questions.
> if we exist in a universe with more than 3 dimensions
That’s a big, hypothetical, and completely unproven “if”. As far as we actually know and can prove, we live in a universe with three spatial dimensions.
You got it wrong. When scientists say, “space is 5 dimensional,” they mean that coordinates of an object in the space-time are defined by 5 parameters. And due to spacetime warping you can create such theories with lots of parameters. It doesn’t mean there is some sort of hyperspace outside of our normal 3 dimensions.
>I’ve often heard extra dimensions described as planes
Those physics theories that hypothesize the existence of more dimensions usually need a mechanism that hides them from us. For example they can be “folded”, wich basically means you can’t move more than a microscopic bit into that 4th+ direction before reaching the end of it.
We are very far away from confirming any of those theories though. It’s just an idea of many that could solve some difficult physics questions.
You got it wrong. When scientists say, “space is 5 dimensional,” they mean that coordinates of an object in the space-time are defined by 5 parameters. And due to spacetime warping you can create such theories with lots of parameters. It doesn’t mean there is some sort of hyperspace outside of our normal 3 dimensions.
I think you’re confusing two different kinds of “dimensions” here. The more scientific definition of dimensions are the 4 dimensions that constitute the 3 cardinal directions plus time (some argue there are more, but that has yet to be supported experimentally).
The other definition you’re using for dimensions is the concept of separate realities that is popular in science fiction writings, for example, rick and morty traveling to parallel universes.
For the more scientific one, you can’t move “out” of the 4 dimensions but you can (and do) certainly move within any 4 of the dimensions in any way you want (except backwards through time, for reasons too advanced for this thread). You can’t leave these dimensions because they make up everything, and you can’t exist within nothing. Also, as I hinted at above, it’s possible that there are more than 4 dimensions in our universe but no one has created any sort of experiment to test whether or not they actually exist. However, *if* they exist, the same logic applies, and you can and do move through those dimensions. That said *if* they exist these dimensions are very *small* and are not noticeable by us.
The other kind of dimension, the parallel universe kind, are scientifically speaking completely different. This is another case of unsupported hypotheses, but *if* parallel universes exist, there’s no known way of traveling to and from them, and speculated on why not or how to do so is a exercise in futility.
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