SPACETIME: FUSION OF SPACE AND TIME INTO FOUR DIMENSIONS

    What is spacetime? Well, spacetime is something where three-dimensional space and one dimension of time combines to form a four-dimensional continuum.

A Spacetime Continuum

    The idea of four-dimensional spacetime bought a revolution in the scientific world, changing the way scientists used to look at the universe earlier. Spacetime explains how the universe works.

    

    We all know Isaac Newton. He was the person who figured out about gravitation. He explained almost everything about it. But couldn't solve one mystery "How gravitation works?".

    Albert Einstein solved this mystery. He explained how the spacetime behaves with a celestial body having some mass. More the mass, the more spacetime will bend and hence more will be its gravity.

                            Earth Bending the Spacetime

    Albert Einstien proposed his Theory of Special Relativity in 1905. Many people link the discovery of spacetime with Albert Einstien. However, very few people know that the idea of spacetime was proposed by Albert Einstein's teacher, Hermann Minkowski, in 1908. And that's the reason we call this 4-dimensional continuum as "Minkowski's space".

    Though, Albert Einstien was the one who discovered the curvature in spacetime. He figured out that curvature in spacetime is responsible for gravity. Then in 1926, Encyclopedia Britannica published an article written by Albert Einstien named "Space-time".

    Spacetime helped scientists to understand the behavior of black holes too. Black holes have immense gravity pull. Black holes have so much mass that they make a hole in spacetime. This means that whatever will fall into it will never escape out, not even light. In the picture below, we can see how different celestial bodies having different masses are bending the spacetime.

                       Effect on Spacetime due to Different Masses

    Spacetime not only explains about the gravity. It also shows how the curvature affects time. Whenever spacetime bends, the dimension of time bends too. Hence, time will move at a different pace in a spacetime curvature for an observer outside that curvature. Time will pass more slowly for that observer while observing a large curvature. This effect is known as "Gravitational Time Dilation".