We do see “relative” changes to the apparent speed of light. For example, it has been shown in several experiments that our relative perception of light’s speed can be changed by light traveling through special types of materials and having the “shape” of photons changed:
However, there may be another way to interpret these changes in light’s apparent speed. When light travels through a material of any significant density, energy from the light is absorbed and re-emitted by atoms in the material. In other words, the light is being “processed” in a sense, slowing down its apparent travel time outside the material, but not the actual light-speed between atoms it is interacting with. Here’s a discussion on this topic:
Changes to light’s apparent speed based on material refraction may not fully explain the phenomena in my first link, where it does appear that the “shape” of a photon may affect its relative speed through spacetime, even in a vacuum. This may be because of the spacetime geometry we cover in M4, which actually determines the speed of light based on its capacity to pass self-similar vibrational waves through it.
Einstein’s theory of Special Relativity and its countless successful experimental proofs form our primary conceptions about why the speed of light is constant. As we discuss in M3, this is because the speed of light and spacetime are intricately interconnected.
What is important to understand about gravity and movement relative to light, is that when you accelerate in any direction, you are “pushing” through the spacetime fabric, causing it to warp or become distorted, which of course distorts TIME as well as space. Planets affect light in this way, because light is simply “riding” the geometry of spacetime, so when spacetime curves, so does light. This does change our relative perception of light, but not the speed that light is actually traveling through spacetime.
If we accelerate to near light-speed chasing a photon, it will seem to continue moving away from us at the speed of light, yet other observers who are “still” relative to our movement will see us almost keeping up with the light beam! This is because in those few seconds we experience zipping after the light beam, we have distorted spacetime so drastically, that even though in those few seconds we might experience chasing that lightbeam to a star 100 light years away, others observing us will see the 100 years pass as we travel just behind the lightbeam.
It is essential to understand that this is due to acceleration, which is exactly the same as gravity, when it comes to the curvature of spacetime. We are bending spacetime, just like a planet, star, or black hole.
Now, if we can learn a technique of traveling without acceleration, perhaps by somehow isolating an object from the surrounding spacetime fabric itself, then we will not have this time-warping problem and light may appear VERY different to us when we’re actually traveling at near light-speed or even faster than light-speed (Superluminal).
We will cover more on these topics in M4 and M6 in the Delegate Program.