Introduction to General Relativity 2

Hello everyone. This is my second post about General Relativity. If you haven't checked out my earlier post on General Relativity I suggest that you take a look there first here. So don't worry and read along, I bet you would like it if you liked my previous post.
As in the previous post. I talked about a person on earth and one in space, and how they are related to each other. This time I am going to chew on this phenomenon a bit more before coming to a conclusion.

Now considering the same box in the previous post, i.e. the person on earth is stationary and the person in space is accelerating with g. Now lets say there is a Laser beam that starts from one end of the box in space (which is accelerating with a speed of g). The laser beam starts from level A. But just as it starts it journey (the photon) in a straight line. The box accelerates and hence when the light travels a little distance before reaching the box's end, the box accelerates and hence the light reaches level B when it has traveled a certain distance. Further, when the light reaches the end of the box, the box moves a distance and hence the light reaches level C when it touches the end of the box.
So what is happening is that the light is going in a straight line, but because of the movement of the rocket the light appears to bend downwards. So the net observation of the observer would be somewhat like shown in the adjacent diagram (of course the bending is negligible for small distances and slow speeds). This movement is in consequence of the movement of the rocket.
Applying equivalence principle and we see that the person on the stationary box on earth will too experience the same phenomenon. If you are wondering what is equivalence principle check it out here.
Hence Einstein concluded that light bends around places of acceleration. As gravity is a form of acceleration and it depends on mass (Newtonian theory). Hence bodies with more mass results in more bending of light.
This effect was proved that this effect actually occurs.
During a total eclipse of the sun, when the sun's light is almost diminished due to the moon covering it. What was noticed was they could see stars which weren't supposed to be seen then because they were supposed to be behind the eclipse.

Because of the eclipse, this effect was observed because otherwise we couldn't see a thing normally because the sun's light is just too bright for us to be able to do so. What actually happens is that the light from the star is bent by the gravitational effect of the sun.
This was the first visual evidence that light bends in gravity field.
Now, one question arises. What if the light is coming directly at the massive object? Will that cause it to speed up?
Well, the answer is no. But yes, it will change the light and some of its properties.
This changing of properties is what we call the Doppler Effect. And it is very similar to what you hear when an ambulance zaps by you. When the ambulance approaches, you hear a high pitch sound and the intensity increases, but when it travels away from you, you can hear its pitch decreasing and so does its intensity. Light, exhibiting both wave and particle nature, too shows Doppler Effect.
Lets now consider a similar scenario as we considered before (that rocket and earth relationship). But this time, instead of fixing the laser horizontally, we fix it vertically on the roof of the rocket. Now, will the light reach the bottom of the rocket?
Well, you have read this far so I presume you have come up with an answer. Lets see if that's true.

The light originates from the top of the rocket accelerating with g. But by the time it reaches the bottom half way. The rocket accelerates and hence the bottom comes up. Because of which the light reaches the bottom earlier. This reaching early causes the wavelength of the light to decrease and hence increasing the frequency of the light. This is what we call the Blue Shift. Because if we were sitting on the bottom of the rocket, due to the movement the light from the origin of the laser would reach us prematurely causing the light to change its color to a color that is towards blue.
Similarly if the inverse situation is presumed and the Laser is shot from the bottom of the rocket and we are at the top of the rocket. The laser light will take longer to reach us. This would cause the inverse of Blue shift what we know as Red Shift.
Simply, blue shift of light happens when the ambulance is approaching us and red shift occurs when the ambulance is receding away from us.
Hence, applying equivalence principle here too, and we see that the way we have gravitational forces, will either increase or decrease its wavelength. So either you get a red shift or a blue shift depending on the gravity of the object and its velocity.
Now for our conclusive topic.
Consider a body moving with a velocity and another body with a constant acceleration. If I draw the graph, what I see is:

Here, the orange line is the line of velocity. A constant amount of distance is covered in a constantly increasing time. The blue line is acceleration. The body covers more and more distance as time passes. Hence as we can see there is a curvature in Space (Distance) and Time when a body is subjected to acceleration. Hence as gravitational pull is a type of acceleration, space time bends around a body which has higher gravitational pull. Hence, you can also relate this to all the above topics in a similar manner.