Gravitational force refers to the attraction of physical bodies with a force proportional to their mass. Newton
Fg= G*[(m1*m2)/r^2]
On Earth, we do not float around due to the Earth’s large gravitational force, whereby the Earth’s mass attracts our mass, pulling us towards the ground. Here, we usesNewton Newton
Fg= G*[(m1*m2)/r^2]
On Earth, we do not float around due to the Earth’s large gravitational force, whereby the Earth’s mass attracts our mass, pulling us towards the ground. Here, we uses
Einstein’s General Relativity theory proposes that gravity is the result of curved spacetime.
According to Euclidean space perceptions, the universe has 3 dimensions of space and one dimension of time. Spacetime combines space and time into a single manifold so as to help physicists simplify the many physical theories and describes the workings of universe in a more uniform way.
A diagram showing 2-Dimensional space time
**Note: The diagram is not drawn to scale.
General relativity described gravity as a geometric property of spacetime. It is the warping of space-time around a massive object, such as a planet. The stronger the gravity, the more space-time is warped and the lower the object “sinks”. Think of spacetime as a fishing net. If you place a fish on the fishing net stretched out, the fish will “sink” into the fishing net, crating an indentation.
An indention of the space-time when an object (e.g. planets and stars) are "placed" on it.
Therefore, what we feel as gravity is due to the curvature of spacetime. Since a massive object causes spacetime to curve, the curvature determines the paths of freely moving masses. These freely floating objects have a straightest and shortest possible path. If you feel weight, then you are not on the straightest possible path. With this, we can use general relativity to explain how the Earth orbit around the Sun. In actual fact, Earth is actually following the straightest path possible around spacetime, but this path happens to goes around the Sun. That is, the Sun is so massive that it makes an indentation so deep for the Earth’s straightest possible path to become an orbit.
Therefore, what we feel as gravity is due to the curvature of spacetime. Since a massive object causes spacetime to curve, the curvature determines the paths of freely moving masses. These freely floating objects have a straightest and shortest possible path. If you feel weight, then you are not on the straightest possible path. With this, we can use general relativity to explain how the Earth orbit around the Sun. In actual fact, Earth is actually following the straightest path possible around spacetime, but this path happens to goes around the Sun. That is, the Sun is so massive that it makes an indentation so deep for the Earth’s straightest possible path to become an orbit.
According to this theory, light travels along the curved space taking the shortest path between 2 points, or we say that light travels along a geodesic path between 2 points in spacetime. Therefore, in the universe, light is deflected towards a massive object. The stronger the gravity is, the greater the light path is bent. This leads to a conclusion: light can “bend” in space. This explains why repeated images of the same distant astronomical objects are visible in sky, a phenomenon termed gravtitational lensing. However, it is also important to note that while light continues to travel in a straight line, it is the space that curves, looking as if light has bended.
