# A better way to imagine the time space continuum.

the_truth
The laws determinning the passage of light through varying densities of transparent material and through varying "acceleration" caused by a common field of gravity have similarities.

I prefer to think of warping of the time space continuum as an increase in density. Light bends as it passes from one medium into a denser or into glass, or in the case of the time space continuum, a field of varying density. In the case of light orbitting a black hole, you would simply have to imagine a very huge change in "density", enough to prevent light from leaving. The very center of a black hole is an infinitely small point and the light would still end up orbitting the black hole in some extremely tight orbit. It would also take a long time to travel through the dense field due to time dilation, which is similar to how light slows down in dense transparent objects. Bearing in mind light cannot gain momentum and if it did have some theoretical momentum (in relation to the displacement it cause when it interacts with a mass) it would take something like 10^50 years to come orbit the center of the black hole and leave out the other end (it's called an event horizon for a reason!).

What do you think?

εllipse
The obvious thing to be pointed out is that spacetime (in GR) is a continuum, but we know that matter is not. Light doesn't slow down when it passes through transparent matter because it is a dense continuum, it slows down because it is absorbed and reemitted by the atoms.

yogi
Interesting article: http://livescience.com/technology/050819_fastlight.html.

Also, there are some very good alternative theories on why light is slowed in a medium - JJ Thompson derived a complete set of mathematical relationships based upon classical principles that conform with experimental results. In summary, Thompson showed that the interaction of the electric field of the light wave with the corpuscles that comprise the atoms of the medium (electrons and nucleus) would produce a separation polarizaion - increasing the inductive capacity of the medium and therefore the refractive index.

Staff Emeritus
the_truth said:
The laws determinning the passage of light through varying densities of transparent material and through varying "acceleration" caused by a common field of gravity have similarities.

I prefer to think of warping of the time space continuum as an increase in density.

This looks like a great candidate for the "theory development" forum to me. It doesn't seem to be about relativity, but about someone's pet theory.

Mortimer
See the work of prof. J. Almeida on "4-dimensional optics" here.
For those who are not inclined to reading scientific literature I will say that the whole theory is very reminiscent of geometric optics in 4-dimensionsional form, hence the designation of 4-dimensional optics. The worldlines of particles and bodies are seen to be the geodesics of 4-dimensional space with signature (++++). The variational principle for geodesics is seen to be the perfect extension of Fermat's principle when 4-dimensions are considered

the_truth
Thank for all the insights, I never thought that light could be absorbed and re-emitted at exactly the same frequency and in the general direction it originally came from, it seems a little far fetched. I thought that most light passed through the electron fields interacting between atoms and the spectrum of light absorbed and let through depended on the frequency of the electron field. I can imagine perhaps light being affected by the electrons. I had better read up on some of the theories and facts put forward on this matter.

"It doesn't seem to be about relativity, but about someone's pet theory."

Definately a bit better than the rubber sheet model..

Staff Emeritus