How many dimensions are there? There are either 4, 10, 11, or infinite dimensions, depending on what theory you read.
What is a dimension? A dimension is the minimum number of coordinates needed to specify a point within that dimension.
We can experience four dimensions. The first dimension is length. A straight line exists in the first dimension. Only one coordinate is needed to specify a point on that line, so it is the first dimension. The second dimension has height as well. If we drew our straight line with pencil just now, then the graphite will stick above the page slightly, giving the line height and pushing it into the second dimension. We now need two coordinates to specify a point. We need the X and the Y. The third dimension has depth. This is the dimension that gives everything we see depth and stops them from being flat objects. The pencil line we just drew will have depth because the pencil is a few millimeters thick, bringing it into the third dimension. We need three coordinates to specify a point here. We need the X, Y, and Z. The fourth dimension that we can see is time. We cannot see time, but we can see the effect it has on things. The pencil line we drew didn’t exist at some point, then it did, and at some point, it and the paper will decay. That is time and the fourth dimension. We need four coordinates to specify a point here. We need X, Y, Z, and the object’s position in space time. Time is a dimension, but we can only move one way through it. We cannot move back in time, only forward.
So, what are the other dimensions? They are theoretical dimensions that are brought up by string theory. String theory is a theory that may be able to unite general relativity and quantum mechanics. General relativity is great at explaining the behavior of very large things. Quantum mechanics is very good at explaining the behavior of very small things. They don’t work too well when you put them together and string theory could be the solution. String theory is the idea that reality is made up of vibrating strings that vibrate at different frequencies and bend in different ways to create different types of particles, such as photons and quarks. However, the math behind string theory doesn’t work unless it has six more dimensions to work in.
The fifth dimension is a universe that is a little bit different from our own. We could use it to measure differences and similarities.
The sixth dimension has all possible universes. They have all started with the same Big Bang, but they have all the conditions that could be possible. If we could access this dimension, we could see all possible futures.
In the seventh dimension, there are single universes that are different from our world because they started from different conditions. This means they probably have different laws of physics. For example, gravity acts differently or the speed of light is different.
In the eighth dimension are all the universes that have started from all the possible conditions. These would be infinite because they would have infinite initial starting points and infinite different laws of physics.
In the ninth dimension we can see all of the laws of physics that govern each universe and all of the conditions.
In the tenth universe, everything becomes possible.
Some theories of string theory call for an 11th dimension. There are also theories that have 24 or 26 dimensions. So, if we have this many dimensions, where are they? We obviously can’t see them. One theory is that they are infinitesimally small. Much smaller than the smallest particle. When two particles collide, the energy produced could rip a hole into one of these dimensions, but it would close up again very quickly. Physicists think that this multidimensional theory could explain why the force of gravity is so weak. Gravity is one of the four fundamental forces, but it is the weakest by a factor of a thousand billion billion. Gravity is so weak that we need an object the size of a planet for it to have any effect. Gravity is so weak that you can jump up into the air, counteracting the gravity of a whole planet. You couldn’t counteract the other fundamental forces that easily. Some people think that the reason for this is we are sharing our gravity with other dimensions.
So, there are three dimensions we can see, a fourth that we can feel the effects of, and six more that are invisible to us. Perhaps there are beings somewhere that can access all of these dimensions. Perhaps not. And this is what I learned today.
Sources
https://aeon.co/essays/how-many-dimensions-are-there-and-what-do-they-do-to-reality
https://www.mentalfloss.com/article/501926/how-many-dimensions-are-there
https://phys.org/news/2014-12-universe-dimensions.html
https://en.wikipedia.org/wiki/Dimension
https://cms.cern/physics/do-we-really-live-only-three-dimensions
https://www.space.com/17594-string-theory.html
https://www.quora.com/Why-are-Quantum-Mechanics-and-General-Relativity-incompatible
https://www.space.com/why-is-gravity-so-weak