Exploring the Unseen: Understanding Space-Time Curvature and Planetary Orbits

 

   Since the very beginning people on earth have been curious about understanding how planets are moving around stars like the revolutionary movement of planets and why planets do not eventually fall into stars. So, let’s try to understand the mystery. We will try to understand the topic according to the view of Newton and Einstein. But we will focus more on Einstein’s view of gravity. Initially, Newton named a force called gravity. Newton tries to explain the planetary motion of planets due to the influence of gravitational force. According to him “ Everything in the universe attracts other body which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them”. So according to him, Sun is at the center of the solar system and the sun attracts the other planets. Now the question arises why planets do not eventually fall into the sun. This is because of the balance of centripetal force and inertia of planets. The gravitational force acts as a centripetal force and this is the force that keeps the planets moving in the circular path just like an object like a stone tightened with string continuously moves in the circular path. The centripetal force acts towards the center of the circle and because of the inertia of the stone, it continues moving around the circular path. If the centripetal force increases than the normal then the object may fall towards the center of the circle and if the centripetal force decreases than its normal value then the object may not continue its motion along a circular path. The same is the case with the motion of planets around the sun. This explanation is in the view of Sir Isaac Newton.

       Now let’s discuss the topic in view of Sir Albert Einstein who tries to explain the whole scenario in his famous general theory of relativity. Einstein considered space as a space-time blanket. Where the massive objects curve the space-time more where the less massive objects curve the space-time less. So, Einstein considered gravity as the curvature of space-time. Consider the space as a rubber sheet and place a big ball in the sheet it will curve the rubber sheet around it and the small ball will curve the rubber sheet less. Same is the case with stars and planets in space. As in the rubber sheet example you will notice that everything near the curvature of the big ball begins to move toward it. Same because of the curvature of the sun in space-time all planets move towards it. But one question arises here in the case of the example of a rubber sheet the small ball eventually falls into the big ball after some time because of the force of friction between ball and the sheet. But in space, there is almost a vacuum so their negligible force of friction moreover because of the balance forward motion of planets, they do not eventually falls into the sun. In addition, the path followed by objects in space is called geodesics. So this is the simple explanation of space-time curvature and planetary motion around the sun.