If someone asks us where we are! And ask our location, We instantly share our location through smart gadgets we have, for example, My location is in the ABC area of Mumbai City. When we share a location, what do we share actually? When we share location, We share our positioning, where we are located in the Three-dimensional space, Three-dimensional space is the X, Y, and Z coordinates, which is height, width, and length.

###### Three-dimensional space

## What is space?

Space is a three-dimensional hollow area in which objects are situated. Space is the void that exists between celestial objects. Void Between the sun and the earth, between moon and Earth, between Earth and Mars, and among all the celestial objects is called space, every object is situated in the void of space. You can say space is boundless If you want!

Well, Earth is a tiny particle of infinite space…Now, what will happen, if we add time to that 3-dimensional space? If we add time to that 3-dimensional space then, it becomes a four-dimensional ‘Spacetime continuum’.

That is the idea behind the ‘space time’ phenomenon. And that’s how space and time are related to each other.

## Origin of the Idea

Great physician Albert Einstein has a great contribution in developing the idea of the space-time continuum. In his special theory of relativity, Einstein developed the idea of a single continuum of space-time in the year 1905. Albert Einstein reached the idea of space-time, by studying two different principles of physics.

First is Sir Isaac Newton's law of physics describing the motion of an object, which is based on the assumption that the laws of physics stay the same inside any given frame of reference.

And second is Maxwell's law of electromagnetic light which says that the speed of light is constant irrespective of its source.

Einstein applied rational logic on that, If these both theories are true, space and time have to be combined together. What this theory says is that if the speed of light remains constant for all the observers then Space and Time have to be changed accordingly.

Thus, Einstein in his special theory of relativity has given the idea that the speed of light is independent of the motion of all the observers, and space and time are connected in a single continuum.

However Discovery of the space-time continuum was a milestone in quantum physics, that was just an idea. In physics, a proper Mathematical model is required to prove the idea. Later mathematician Herman Miwonkiski developed a geometrical model that proves the single fabric of space-time.

## Time: An independent entity

In classical physics, time is considered as an independent entity, Why? Because time is a one-dimensional entity that is believed to be constant and moves only forward in classical physics. Time constant means the duration of the time is constant. For example, 60 minutes makes 1 hour. That value is a constant either It is measured in India or the USA (united states of America)

### Is space-time relation really true?

Quantum physics won't agree with this concept, many physical phenomena don't follow this rule. According to quantum physics. ‘Pace of time can be different from the reference and velocity of the object in space.’If we take a hypothetical example of a spaceship that can move faster than the speed of light, then time will slow down for the spaceship. Similarly, two observers who are in relative motion with each other will see the same events in different time duration.

There is one fascinating idea about space, it says that the star you are watching from here the Earth, it is possible that it might not exist. It is possible that it died. Yet, You can see the star because earth and star are located in different positions in the space-time fabric. That means the time has been affected, it is not constant. It has been explained by the special theory of relativity which says "when an object moves into the space, the time has been affected because space and time are single continuum".

## Interwoven concept of time and space

Space is not a three-dimensional void, but it is interwoven with time, popularly it is considered as a sheet of rubber, which you can see in the picture.

###### Interwoven concept of time and space

All the celestial objects are located in this four-dimensional continuum. The position of celestial bodies in space-time fabric is the distortion, this wrap is not just in space but in time also, that's why time can expand and shrink when the distortion takes place in the spacetime fabric.

###### four-dimensional continuum

This theory also adds gravity to the mix. In classical physics, gravity is defined as a force of motion, but Albert Einstein in the year 1915, a decade after he gave his theory of special relativity.

Give another theory which is the general theory of relativity. This theory explains that the force of gravity is due to a curve in the fabric of spacetime.

## Mysteries that are unsolved

Though the concepts of general relativity and special relativity have solved many physical phenomena, this model is incomplete. Relativity is still not harmonized with Quantum physics. Quantum physics considers everything is made up of tiny particles, it studies the subatomic particles. But gravity has not been understood fully with quantum physics principles. One assumption regarding space-time is that like light, which travels through a chunk of the particles called photons, similarly, space-time fabric also moves in these chunks.

So, it has been widely accepted that space and time are interconnected with each other and that makes the space-time continuum; a four-dimensional entity.