Can you explain to me how time is regarded as the 4th dimension? Does it mean that if we assume time as a dimension then an object traveling to different time period is possible?
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The math Einstein found points on this interpretation calling the whole construct “spacetime”. But we cannot move in direction of the time freely. Its kind of we are falling in direction of time with lightspeed 😉
This is probably way too late to get seen, but:
We think of dimensions in terms of shapes and space, but really a dimension should be thought about as some *independent* feature that can be changed. So you can think of a piece of clothing: say, a shirt. That shirt might have a dimension for material, a dimension for size, and a dimension for color. There would be more dimensions if size were broken into length, width, height, like we think of for more traditional geometric shapes, but we can assign any number of dimensions as long as we agree that the new dimension is *independent* from the others. In this case, it is true that we can change the color of the shirt without changing its size or fabric (at least when we are designing it).
Another way we can think of dimensions is with a circle. Traditionally we think of a circle as a 2D geometric shape with width and length (or height, whatever). However, a circle *really* only has one “side,” because its width and length are the same. This “side” is its radius. You change the radius, the size of the circle changes. We can completely control the size of the circle by changing the length of the radius. In this sense, it really only has one dimension.
Time is a dimension because it is a variable that can change independent of what we think of as the “traditional” dimensions of position (e.g. length, width, height, or x, y, and z coordinates). In classical Newtonian physics, the 3 dimensions of space are the most important and the ones we discuss and experience most readily. They are highly *visual* dimensions because they affect shapes and relative positions of objects and we are highly visual animals so this carries a lot of significance. As technology grew in the 80s and 90s we talked about “3D” graphics for computers, games, and movie effects, so this idea of “3 dimensions” is anchored strongly in our collective psyche, but these aren’t the only dimensions.
Mathematics can describe any number of dimensions. Again, a “dimension” is really just a feature that can be changed independently of others. Time is the “4th” to the traditional 3 dimensions of space, but there are many more dimensions we can assign to objects and there are even advanced scientific concepts that observe and study more dimensions.
It’t not *the* 4th dimension. The average human can grasp three space dimensions, and time. Calling the time dimension ”the fourth dimension“ is just an unfortunate naming convention in pop science. Better think of them as, e. g., S1-3 (space) and T. Or call them Jim, Tim, Fin and Deidre.
For me it helps to observe the difference between a 2D and a 3D object. Carl Sagan has a great video he does with little pieces of paper.
He takes a few tiny pieces of paper and puts them on a table, the paper pieces represent 2D creatures, the table is their entire plane of existence. Then he picks up one of the pieces of paper. In the perspective of the other 2D creatures it has simply popped out of existence, but to us all that has happened is it rose up a few inches. Now Imagine if your computer were to suddenly move forward in time, same thing, it would seem to simply pop out of existence in the same manner.
A 2D creature cannot affect the 3rd dimension, but a 3D creature can affect the 2nd dimension. In the same way we cannot affect time, but time can affect us.
Now take one of the pieces of paper and slide it across the table, the 2D being has just moved through its 2D plane, while also moving through the 3D plane. In the same way, while we move through the 3D plane we also move through time.
Now if you can, try to Imagine a 4D being as one who is capable of moving through space and time as easily as you or I might walk across a room, and one who might observe us as little more than tiny pieces of paper sitting on a table.
According to Einstein , you need to describe where you are not only in three-dimensional space* — length, width and height — but also in time . Time is the fourth dimension. So to know where you are, you have to know what time it is.
If i told you to meet me somewhere it would require 4 dimensions. A 3 dimensional space and a time. So say a building at a specific street junction (the 2 dimensional coordinates) and a floor (the third dimensional location) and a time. Without those 4 required dimensions we can not meet.
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