WHAT IS GRAVITY? (EINSTIEN’S VIEW)
The definition of gravity that we usually study in our schools defines it as a force that attracts things towards the center of the planet. However, the reality is much more different than assuming gravity merely as a force. Thinking of gravity as a force occurred in our mind due to the lack of instruments that could otherwise explain that what the space around our Earth is made up of. 80% of the mass of the universe is invisible and we do not know what it is composed of.
While giving the explanation about what actually gravity is in the General theory of relativity (1915), Einstien said, forget about the gravity as a force instead think it of as a shape in space-time changing due to the uneven distribution of mass. Einstien’s point was, what we see as the mysterious forces are actually twists and curves pushing us in a certain direction.
This can be explained by a rather strange example of a sphere.
Let’s assume that two people are standing at the equator of a sphere. They set off by moving parallel to each other. But what they don’t know is, they are moving on a sphere. They were of the view that they are moving in a straight line which means their path should never meet, but as they got closer to the top, their paths got closer together and eventually they end up meeting. If these people try to figure out how it can be possible then the only possible answer they could give is: there should be some mysterious forces that pushed them closer together. What they didn’t know is, they were moving parallel on a sphere.
The point is, gravity does not act upon us, rather it acts upon space and time around us which is called the geometry of space-time. As an example, why a person feels weightless and doesn’t feel like any force acting upon him when he stands in a moving lift? Because it is a misconception that gravity is a force.
The three-dimensional space is the stage in which things happen and the matter curves the space-time around it. Gravity is now defined as space-time warped around the structure like Earth.
Effects of gravity:
Since we have completely understood what gravity is, we should now look into the effects it has on different things on the Earth.
· Your weight is the result of your mass and gravity
It has been explained very clearly by the scientists that our weight decreases when we move to the place where gravity is less. For instance, if on Earth we tend to move towards the center of the Earth, our weight increases on the other hand, if we move away from the center our weight decreases. It is because the effect of gravity is stronger towards the center of the planet which means our weight is the result of gravity.
· Moon attracting sea waves is due to the gravitational pull of the moon.
Sea tides that occur at night can be clearly seen and it has been explained by the scientists that this occurs due to the gravity of the moon which attracts the seawater towards it as a result of which we can see high tides.
· Gravity have effects on light too
Gravity tends to have its effect on light too which was discovered by Albert Einstein, light appears red when we move the light source upwards which we cannot see with our eyes but it can be measured.
· Gravity slows down the time
If we place two clocks one higher and the second one lower to the first one, the second clock will slow down due to gravity.