Can We Observe the Bending of Light in Relativity?

AI Thread Summary
The discussion explores the bending of light as described in Einstein's theory of General Relativity, particularly in the context of acceleration versus gravity. It explains that when an object like Sara in a space shuttle accelerates, the light beam emitted from her torch bends due to the relative motion between the light and the accelerating frame. This bending is not visually perceptible to the human eye but can be observed through astronomical phenomena, such as light from stars bending around the Sun during an eclipse. The conversation emphasizes the equivalence of acceleration and gravity, illustrating how mass influences the curvature of space-time. Overall, the bending of light is a fundamental aspect of relativity that can be observed under specific conditions.
Turkish
Messages
33
Reaction score
0
Hi, this may seem like a really easy simple question, but I've not yet managed to figure it out. Yesterday I was looking through the encarta and I came across 'Relativity' so I started reading about it, on one of the demos it said;
'When Sara is standing still in space she switches on a torch and the beam is straight'
However
'When Sara is accelerating in a space shuttle up and she shines a torch the beam bends'

Now I am thinking, if the speed of light is somewhat 300mill m/s or something, how would u be able to see the light bending?
If any of you play games you may come across something called FPS, hypothetically speaking if you set your fps on 200 and u play this certain game then change it to 250 you won't be able to see any difference (unless the game has certain smoothing) so therefore wouldn't this be the same idea of light bending due to its speed being so fast the eye cannot process this and therefore your unable to notice a bending effect; or am I wrong?

Thanks In advance
 
Physics news on Phys.org
Well imagine light as several rows of particles. Let say she is moving and she lights up a torch. The first row will move perpendicularly to the direction of the ship. Since light does have a length-wave (its magnitude depends of the circumstances), and thus a period, the second row takes a certain time to quit the torch. Meanwhile, the ship has moved. For this reason, row 2 will not be completely aligned with row 1. So for row, row 4, etc. I do not think the bending was meant in the way your eye sees it but physically. ;)
 
Last edited:
The article did not SAY she could SEE the light bending! It just said the light WOULD bend. That can be observed, for example, with light that passes very near the sun.
 
Last edited by a moderator:
I'm going to take a stab at this question, although I'm sure that people after me will give a much better explanation.

The passage you are reading is giving an example of one of the main effects of General Relativity (also known as Einstein's theory of gravity). In GR, Einstein showed two things that have to do with that passage. First, acceleration is the same as gravity. Suppose that your in an elevator with no windows. If the elevator is on the earth, then if you drop a ball it will accelerate downards at g=9.8m/s/s. But what if you were in empty space accelerating at g? If you dropped the ball it would still accelerate down at 9.8m/s/s. So how do you know the difference? More specifically: How do you know the difference between gravity and an accelerating body?

One of the more interesting (at least in my current opinion) that comes out of this equivalency between gravity and acceleration is the bending of space-time. The statement is "Matter tells space how to curve and space tells matter how to move." When space-time comes to a mass, it curves around, much like a piece of tissue curves when you put a weight in the middle. Draw a bunch of parallel lines on a piece of paper. Then hold out that piece of paper and place a coin in the centre. Notice how all the lines start curving? That's what happens.

Now as for seeing it, it's a lot simpler than you think (and it's used a hell of a lot in astronomy). The closest big mass to the Earth is the Sun (and you can use Galaxies instead from what I've heard), so it should bend light a bit. During an eclipse astronomers pointed their telescopes into the sky and took pictures of the sky. When compared with pictures that you would normally see, they were able to see a star that should be covered by the Sun. What was actually happening, was the Sun was bending (or lensing) the light from the distant star around it and onto Earth.

Since Einstein showed that gravity is the same as acceleration, the same would be for Sara in her space shuttle. When she accelerates, the light beam actually bends.

Imo
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...

Similar threads

Back
Top