What is the dimensions?

Answer 1

"another universe, but also, an alternate universe, a parallel earth."

This above is correct, but vague.

A dimension is a property of an object. That object could be anything at all. But when you describe that object, you will have to describe the properties of the object, and you will generally be describing dimensions without knowing you are doing it. In actuallity there is a limit to the properties (dimensions) of an object, but for the most part it can be thought of as a huge number of properties.

So for a simple example. I will describe the dimensions (properties) of a box.

The box is 10 cm wide, 10 cm tall, and 10 cm deep, and is rectangular. It is sitting with the bottom of the box raised on the left side 5 degrees above the planar. The box is Red. It is not moving. And if you touch the box, it has a sandpaper like feel to it. The box is 10 cm directly infront of you.

So we have described relative to your perspective, the XYZ location of the box, its length, width, and height, its relative shape, its velocity, the radiation wavelength it is emitting (color), and its texture, which is a description of 10 dimensions of this object. There are far more dimensions to this object, but for simplicity we will leave it there.

Be careful to understand however that some dimensions are related, however in the above example all of these are independent of one another. Meaning that the texture of the box does not determine its velocity, the velocity alone does not determine the color, etc. So these would not be related at all, hence why they are called independent dimensions.

Now let me clarify the above answer to make it less vague. How can an object that is the same in every way except location, be an entirely different universe?

Take for instance the painting, The Mona Lisa. If it was not on display and was instead always in a box never to be seen, it would not create the fame, and interest in the picture and all the other dimensions of what we experience. We would not even be able to describe the basic physical properties of the painting in any dimensionality. We would probably not even know that the picture existed at all, pretty much like most art that has ever existed.

I hope that answers your question.