For Curiosity's Sake

Question 2: Are There Other Dimensions?

The easy answer to this question is, "Yes." But that answer would make for a short and unsatisfying chapter. So, let me first explain what a "dimension" is, in this context.

In simplistic terms, a dimension is a measurement of something in space or time. From our perception, there are four dimensions, three spatial and one of time. So, we know side to side, front to back, up and down, as well as future and past. We can move in the direction of any of these, except past*.

Scientists are constantly looking for a way to relate what's known and the "four fundamental forces". Two of them, gravity and electromagnetism, you may have heard of, but there are two more that work on a quantum (very, very small) level that you might not have: weak interaction and strong interaction forces. We're going to just wave our hands at the explanation of these and assume they exist without explaining them.

In an effort to make a connection between all of these forces, scientists have developed theories that must assume there are more spatial dimension that the ones we experience. Each dimension is at a right angle to all the other dimensions and, in all honesty, it is impossible (perhaps only in my opinion) to even imagine them.

We can, however, see the consequence of the next higher spatial dimension. That consequence is known as a tesseract. It is a three-dimensional projection of a four-dimensional object.

This is a two dimensional representation:

If you're good with stereoscopic images, here it is in three dimensions (you may have to look up how to view these kinds of images):

https://upload.wikimedia.org/wikipedia/commons/2/22/3D_stereographic_projection_tesseract.PNG

Now, because we are constrained by our very existence to live in three spacial dimensions, envisioning an actual tesseract is beyond us. Carl Sagan, in the television series from the 1980s called Cosmos, explains why using the example of "Flatland". I encourage you to watch this video; it does a much better job than I can with text as dimensions require a visual to completely understand.

Note: While the video clip is just a portion of the episode, you can find the full transcript here, if you need it: https://www.springfieldspringfield.co.uk/view_episode_scripts.php?tv-show=cosmos-carl-sagan&episode=s01e10

So, we are living in three dimensions and the tesseract is from the dimension above us. We can't experience that dimension, but we can see the projection of it. String theory, the current most prevalent theory to explain the interaction between the four fundamental forces, suggest that there are eleven dimensions in total.

Thus, our answer of, "Yes, there are more dimensions." At least, we think so.

*We are prevented from moving into the past due to the 2nd Law of Thermodynamics which states that all systems tend to naturally move in the direction of "increasing entropy". This means that the universe is getting more and more disordered over time; things are cooling off.

If we traveled backward in time, this means that things would be getting hotter and hotter, which doesn't happen without help. Thus, we'd need some kind of mechanism to make that happen and move us into the past. One such mechanism has been theorized: wormholes.

For a little more on string theory and wormholes, check out this video: