Here it goes, here it comes! Really long time (means few years) I was wondering about dimensions. It started when I was watching videos like: how to imagine higher dimensions, what are dimensions and so on. At the beginning I did not understand any of it.

As time went on I accidentally bumped into black holes and later on into wormholes (actually this post has some mistakes as for  example it is saying that time is fourth dimension.) which should  connect space through higher dimensions and make a shortcut through Universe (picture is from here).

Ok first of all lets clear out some things. This post can have some mistakes, but I hope that there wont be any.
Second, fourth dimension is not really a time. The thing is that time does not work like space dimensions. Space dimensions also known as spatial dimensions, are the dimensions in which we can move forward, backwards, horizontaly, verticaly.. like in our world. Time is not so free, it runs just one direction and it is special type of dimension called the temporal dimension.
We live in 3+1 dimensional world.

Ok so what are those normal spatial dimensions? Well I will start with the most simple dimension, 0th dimension.
On the picture you can see 0th dimension, pretty fun huh? It is point, and point has no volume by the way, this one is just enlarged. In 0th dimension you can not do anything, I am serious.

The problem is that if you lived in 0th dimension you would not be able to imagine 1th dimension because it would be like imagining new color which you never saw.
When it comes to creating higher dimensions ALWAYS you have to copy the lower dimension infinite amount of times. This means that if you want to have 1st dimension which is line you have to line up infinite amount of points from 0th dimension. As you probably know from math there is infinite possible places to place point on line.

So here comes the 1st dimension which is line made up of infinite amount of dots. On line you can place all of the real numbers.
In the movie Flatland, which is fun movie you watch the line creatures to move back and forth because they live in 1st dimension.

I dont need to put any picture of second dimension, since you see it every day, on your computer, book on board in school.
To create 2nd dimension, again you need infinite amount of lines next to each other to create plane. Now 2nd dimension is pretty useful, for lot of stuff from: graphs, photos, any text, movies… you know I could continue for long time.
So the standard object of 3rd dimension is cube. Again when you want to create it you need infinite amount of planes because they dont have any thickness.
Well now we are in our world but of course I can continue for the fourth dimension.

Ok the problem is with imagining 4th and higher dimensions on their dimension. By this I mean that I can easily draw on plane any dimension but it is just impossible to imagine 4th dimension since in our world we dont have space to expand it into. Over time I found some things that can help you anyway.

In one episode of Futurama Doctor says: if you looked from fourth dimension to third you would see inside of this egg as when you look from third dimension to second and you can see egg’s inside. I would say that this is little mind bending. In fourth dimension there is direction in which you can move but from here we can not imagine the direction since it seems that we can already move anywhere.
Finally here comes the drawing of dimensions: Always the angle between new dimensions is 90 degrees. In

third already you have to imagine it because if you would measure the angle on the plane you would have about 60 degrees. But it continues and the angle is still 90 even if it seems impossible. 5th dimensions is just expansion of all of those dots to another direction and so on and so on (the picture is from here).

Actually from plane you can see 3rd dimension with pretty neat trick that I found some time ago. On the next picture there is 3D object in 3D, 2D and 1D. To see the first one in 3D you have to look as you would look behind it so there are fourth of those objects on row. At one point those objects would be only three because two would be over each other. If you are precise enough you can match them well enough to see the picture in 3D.
Well this is about it. (The last picture is from here.)
If you want to read about more time dimensions, check this page.
The person there assumes that with 2 time dimensions you would be able to turn around in time as you can turn around here.



Hi! So what is a wormhole?
Wormhole is kind of similar to black hole.
It does have really strong gravitational field but not that much as black hole. The thing is that black hole bends space time much more than wormhole — it has singularity in the middle. Wormhole does NOT have singularity, because it does not have enough strong gravity.
When it does not have singularity it also can not have event horizont.
So what makes it a hole?
When it bends spacetime it can create tunnel from one point of universe to another through higher dimension this could be used for traveling really long distances. Black hole cannot do this because its gravity is too strong.

WormholeNow it is clear so lets move to spacetraveling through wormholes. First you can imagine it with lower dimensions which are pretty easy. So 0th dimension is pretty useless since it is just point so we will jump right for 1st dimension. It is only line, not very complicated right? You have line which 1km long. You have to get from one end to another but you dont have enough time. You will take shortcut through 2nd dimension! You will take this line and bend it to circle, so now that point which you wanted to visit is right next to you! From 2nd dimension to 3rd it is also very easy to imagine, you can actually see it above. Take a paper (that is your space) and on one edge draw point and draw same one on opposite part. Then bend this paper so those points are touching, you have been traveling faster than light! Well it is not fair, it´s like saying Usain Bolt to run 1000m and you running only 50m, quess who will win, light.
It is named wormhole because worm in apple is using 3rd dimension instead of traveling on the surface of apple.

Problem with wormholes is that higher dimensions than 4th (which is time) are only in really small scale: 10^-33 centimeters. This length is not really usable for traveling but really old wormholes could be bigger caused to expanding of universe. Another problem is their stability because they would need to have lot of “exotic” matter to last longer than moments. Last thing is that wormholes are only hypothetical, wormhole has never been observed.

PS: I have edited it once because there were some mistakes and it did not make any sense before.
PSS (26.11.2015): light is not 4th dimension as you can read in this post.