Gravitational light refraction?

[Caustic]

I noticed when I look very closely at just about any object with a curved surface with a straight line behind it running almost parallel to the edge but still intersecting it (or almost) that the line will bend toward the object as if the light is being attracted to it. we all know that the power of gravity is inversely proportional to the square of distance, so when you look very closely at the edge of a massive object, maybe the gravity from the mass of the object is actually strong enough to visually refract light due to the short distance? is this possible, or is this caused by some other Phenomenon? I know this takes place around super massive objects like black holes, but has this ever been observed on a smaller scale?

[Guest spacetime1]

I think the phenomenon you have observed is diffraction of light i.e. bending as it encounters a slit that is of the order of its wavelength.

 

spacetime

http://www.geocities.com/physics_all/index.html

[swansont]

I agree that you are seeing diffraction, but gravitational lensing has been observed. You need a big mass, though.

 

(I think a Google on {gravitational lens quasar} would yield good results)

[Caustic]

when you get closer to an object, the force of gravity will increase exponentially. If you could zoom in close enough to the surface of an object, and take percise measurements, can true gravitational refraction be observed around "small" objects such as a ball bearing, or bowling ball, or the moon? Even a small gravitational force should affect the photon's path as least a little. And when a photon passes a large curved surface which causes the photons path to go very close to the surface for a relatively long period of time, shouldnt the photons path bend around the surface?

 

Im wondering if this happens enough for it to be observed and measured in an ametaur experiment using easily obtainable equipment.

[Cap'n Refsmmat]

I think that would require humoungously precise measurements.

More than I could expect out of easily obtainable equipent, or more expensive equipment at that.

[istok]

it is impossible to do such an experiment on Earth, because there is no way to isolate only one small object and record its affection on light beams. You would have much more influence on the light bending from the moon, for example.

[[Tycho?]]

Light bends when it passes through a gravitational field. It bends by a very very very small amount, but it does bend. You would not be able to detect this with the human eye.

[Ophiolite]

I noticed when I look very closely at just about any object with a curved surface with a straight line behind it running almost parallel to the edge but still intersecting it (or almost) that the line will bend toward the object as if the light is being attracted to it. QUOTE]

 

Optical illusion. Almost certainly/probably/maybe - delete as applicable. Where's a perceptual psychologist when you need one?

[CPL.Luke]

heres what probably happens light acts like a wave. so when you shine a beam of light just parellel to the wall it will become wider with time and hit the wall.

 

its not gravity just quantum/classicle mechanics

[[Tycho?]]

heres what probably happens light acts like a wave. so when you shine a beam of light just parellel to the wall it will become wider with time and hit the wall.

 

its not gravity just quantum/classicle mechanics

 

 

Ummm, no? The wavelength increases for a few reasons. If it is moving out of a gravitational field it will lose engery. If you are moving away from it when you detect it, it will appear to be of longer wavelength. The expansion of the universe causes wavelength to stretch out over large distances.

 

These occur on an astronomical scale, and would not be detectable with the human eye. Plus, I'm not sure what you mean when you say it gets wider. It gets wider in what way, and how would this effect anything?

 

This is an optical illusion anyway.

[CPL.Luke]

you misunderstood my post

 

I meant the diameter of the beam would increase

 

its impossible to directly view the distance between photon however if you see blue light and then you see red light you can then know the beam of red light had a longer wave length than the beam of blue light

 

back to the topic

light has a tendency to spread out (in terms of diameter)

for instance a laser with a beam diameter of 1 cm when it first fires.

 

will produce a spot slightly larger on whatever it hits

[swansont]

back to the topic

light has a tendency to spread out (in terms of diameter)

for instance a laser with a beam diameter of 1 cm when it first fires.

 

will produce a spot slightly larger on whatever it hits

 

Right. But that's just the nature of optics.

 

It's a common misconception that lasers produce parallel light.

[CPL.Luke]

yeah so I was trying to say tht that was the source of what he was thinking he saw with gravitational light refraction

 

the beam was just wider than what he believed it to be

[Guest mahill]

May I join this discussion? It is probably stale by now, but I believe I observe the same phenomemon.

Please respiond to hillm@acm.org or mahill@us.ibm.com

Thanks

[mezarashi]

Personally I believe that any "bending" you see is a result of an optical illusion or some other physical phenomenon such as diffraction. Using the simple elevator thought experiment like of Einstein's, you see that in a gravitational field a horizontal ray of (such as Earth's) light will bend vertically by (delta), where

 

delta = 1/2gt^2 = (gr^2)/(2c^2)

 

where r is the horizontal distance travelled by that light beam, and g is the gravitational acceleration. This is of course using the elementary kinematics equations.

 

Given this rough estimate, if you conduct your "amateur" experiment along a 1km stretch of road (r = 1000m), then you will get a displacement (delta) of

 

delta = 9.8*(1000^2)/(2*(300000000^2))

delta = 0.0544 nanometers

 

(So you decide that you have some equipment that can measure that, let's add in some more fun facts)

- diameter of a hydrogen atom: 0.1 nanometers

- curvature of Earth per kilometer: 10-15 centimeters

- approximate divergence of a good laser beam: 60 millimeters at 1 kilometer