If an object has only length, it is considered to have one dimension. If it has both length and breadth, it is considered to have two dimensions. If it has length, breadth, and height, it is considered to have three dimensions.
Objects with these three types of dimensions require a specific place (or) space to exist.Therefore, the term "space" encompasses the three dimensions of length, breadth, and height.
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An object in a specific space or location can be described not only by dimensions like length, breadth, and height but also by another dimension called "time".
Time is a dimension that moves forward only, unlike length, breadth, and height, which allow an object to move in all directions within three-dimensional space.
As time progresses, the rate of decay or the entropy of an object continues to increase. This is why phenomena such as leaves falling from trees, iron rusting, and fruits ripening occur. If time were to stop, none of these changes would take place. Hence, time plays a crucial role in describing an object.
The spacetime fabric:
The "spacetime fabric" is a hypothetical structure created by combining space, which contains all three dimensions, and time, which is the fourth dimension. But why does it need to be created?
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| Image credit: wikimedia commons |
According to physicists, the concept of the "spacetime fabric" is used to explain the effects experienced by an object moving close to the speed of light, as well as the motion of objects with immense mass.
The concept of "spacetime" was first proposed in 1908 by mathematician Hermann Minkowski. However, even before this, Albert Einstein had predicted the interdependence of time and space in his special theory of relativity. According to his theories, the speed of light remains constant in all parts of the universe.
If you were to travel at a speed close to that of light, your time would move slower compared to someone stationary at a fixed position. Additionally, the lengths of objects in the direction of your motion would appear to shorten. However, you would not perceive these changes yourself. Only those moving at a slower speed than you or those observing you from a stationary position would be able to detect these changes.
Therefore, when an object travels at the speed of light, changes occur not only in its three dimensions but also in its time. This is because space and time are interconnected, and both vary depending on the speed of an object.
In the "spacetime fabric," formed by combining time and space, placing an object with significant mass causes it to bend inward. This bending alters both space and time accordingly.
For example, when an iron ball is placed on a rope cot, the surface bends inward. Similarly, the fabric of spacetime bends. However, there is a slight difference in this case.
The surface of a rope cot has only two dimensions: length and width. However, the fabric of spacetime possesses four dimensions, including time.
Time is considered the fourth dimension along with length, width, and height by many researchers. Therefore, when the fabric of spacetime is curved, its time dimension also undergoes a change. Moreover, only objects with a specific mass and density can curve both time and space.
