Question

Write about how light is affected by gravity? in 2-3 pages paper in APA format

Answer 1

Is light affected by the gravity?

yes, The light is affected by gravity , but not in terms of speed.

General relativity gives the two effect of gravity on light.

1. It can bent the light which includes effects such as gravitational lensing.

2. It can change the energy of light by shifting the frequency of the light not by changing its speed.

Gravity bends light by wraping space so that what the light beem see as " straight" is not straight to an outside observer. The speed of light is still constant.

how gravity bends the light?

Due to the presence of any massive object in space , the space-time near that object become curved , due to its gravity.

Time runs slower wherever gravity is strongest and this is because gravity curves space-time. This effects the time elapse between two events by observer at different distance from a gravitational mass.

We can understand this through a simple equation

Distance =speed × time

Speed of light is always constant as the postulates of Special theroy of relativity.

Imagine two beams of light travelling between 2 points in two ways,

1) in the absense of any gravitational mass nearby.

2) in the presence of gravitational mass

In th second case path is curved because the space -time continumm is curved due to the presence of gravity. The distance travelled in the second case is greater but because of the fact that time runs slower near strong gravity , therefore speed of light would be same .

In this way gravity bends the light.

This bending of light we can see in gravitatonal lensing of light. The light coming from the distance galaxy which otherwise cant reach us , reaches us due to its bending because of the presence of other galaxy neat its path.

How gravity changes energy of light by shifting its frequency?

Photons are affected by the gravitation field besides of the fact that it is massless. Photons dont have mass but do have momentum.

The work that gravitational forces does on the photons does not mean a simple concept of increasing its kinetic energy. Lets look this phenomena from point of quantum field theory, we must acceor that the gravity penetrates the structure of photon and in addition to increasing its energy it also increases its electric and magnetic field intensity.

Thus from a quantum perspective, that photons unstructured, it is impossible to explain this phenomena. Therefore , if we want to analyse the structure of photons, we must pass the quantum space and enters in sub quantum space.

From the perspective of subquantum space, a number of gravitons enters into photons structure and increases its energy.

Now question will be arises like how many gravitons enters into the structure of photon that generates the smallest possible change in energy is dE=hdv.

Also the change in energy of photons is associated with change in intensity of electric and magnetic field.

Due to this reason we have theory in which graviton have properties that when gravity works on photon, can alter the intensity of electric and magnetic fields if photons.

So in this way it is explained how gravity affects light .

Note for student:  I didnt know how to write is APA format. So i have just given the answer. Do upvote if u understood the explanations.