If Gravity Isn’t A Force, Then What Is It?

Usually, when we think of gravity, we either think of Isaac Newton under a tree as an apple falls on him, or we think about that force that keeps us grounded or makes objects fall.

To define gravity simply, or as per Newton, gravity is an invisible force between masses that attract each other.

It is a pull. You can also think about how the planets are in their orbits due to the gravitational pull of the Sun, or how the black hole sucks in every passing object due to its huge gravitational force. 

But, some scientists and researchers believe that gravity is not a force.

It is much more complex than a force.

Gravity is not a force according to them. But, if gravity is not a force then what is it?

How else can one explain gravity and what does it do?

How is time affected by gravity? Is Gravity real? 

General Theory of Relativity 

One of the most famous theories of gravity not being a force comes from Albert Einstein.

This complex theory completely dismantles the idea that gravity is a force.

Instead, Albert Einstein claims that gravity is a curvature in space and time. 

a. General Theory of Relativity states that everything in a gravitational field will fall at the same rate, If you throw a hammer and a paper on the moon, then they will reach the surface of the moon at the same time. 

b. This will happen to every object irrespective of its mass, size, or shape. This is called the equivalence principle

c. Einstein used to develop his theory of relativity. His theory says that gravity is an effect that warps space and time when there is mass present.  

d. When there is no force acting upon an object then the object will continue to move in a straight line.

Draw a line on a sheet of paper, now twist the paper- the line will not be straight anymore.

In the same way, gravity bends spacetime in a particular way so that the straight paths of the objects are always bent in the same way when they are near the Earth. This is one possible way that gravity can affect time. 

Frame Dragging 

This effect can be seen near the Earth. The frame-dragging effect occurs when spacetime is twisted.

The Earth is rotating, so it doesn’t just curve space-time as per its mass, but also due to its rotation. 

This can be measured by the Lense-Thirring effect.

To measure it, you need to put a spherical gyroscope in orbit.

Then observe its axis of rotation changes.

If frame dragging doesn’t exist then the orientation of the gyroscope will not change. 

However, if there is frame-dragging, then the orientation will change to prove that there is a twist in space and time, which as per Einstein is gravity. 

Time Delay Experiment 

The popular time delay experiment also tries to show how gravity is more than just a force. The mass of the Sun bends the space that is near it. 

a. The light that passes near the Sun, thus, usually doesn’t travel in straight lines. On the contrary, it tends to follow a curved path which is longer. 

b. This means that the light from a planet that is on the other side of the solar system from the Earth will reach a little later than it should. 

c. This was first discerned by Irwin Shapiro in the 1960s. Radio signals bounded off Venus from Earth when two planets were on the opposite sides of the Sun. The delay that was measured if the signals’ round trip was 200 microseconds. This is also called the Shapiro Time Delay. 

This evidence fits with the Theory of General Relativity and Einstein’s explanation of gravity. 

Gravitational Waves 

Gravitational waves are essentially ripples that are similar to the ripples in water when you swirl your finger in the water.

While these waves are yet to be seen by the human eyes, evidence suggests that they exist in space. 

Creation Of Something From Nothing 

If gravity was just a force then it would become hard to explain the expansion of the universe.

When we think of gravity, we can see that the universe can produce a vacuum from nothing.

Black holes are one such celestial wonders that are a vacuum and are created from nothing. 

There is a stretching and twisting of space and time that leads to the creation of more vacuum substances. 

Cannot Be Calculated 

Forces can usually be calculated. If gravity was merely a force then it could be calculated easily.

However, that is not the case, which makes gravity even more special.

Albert Einstein’s versions of gravity have no means of calculations. 

In quantum physics, you will get infinite terms if you try to calculate gravity, making it impossible to calculate. 

NASA and other scientists have done several experiments to show that gravity isn’t just a force that exists between masses.

Gravity has the power to affect space and time.

It isn’t just what keeps you grounded to the earth, but is a basic fabric of the universe.