Unravelling the Mystery of Light Speed and Naivety

[berty]

Light speed naivety??

The speed of light - c is a fundamental constant, at least in vacuum.
However, it appears that c varies and slows down at the interface between different density materials ie: air to water. But why is this?

If a) photons travel between particles and b) the space between particles is empty then the only reason why c slows is because of the interaction with said particles. If this is the case then why doesn't c slow to nothing whilst traveling and interacting with particles during it's 15 billion light year journey from the edge of the Cosmos to our eyes?

If a) is correct, but b) is not because of the various energy emissions and elemental forces the photons encounter (ie:- do the photons lose energy?) in the less than empty space between particles, then does c vary because of it's interaction with them?

Or is it a combination of factors and if so what are they and what determines their effect/s?

If anyone can answer this query could they e mail me at:
bertiep@yahoo.com

 

[loseyourname]

You should ask this in the Classical Physics forum.

 

[R0man]

It is not entirely accurate to say that the speed of light varies and slows down at the interface between different density materials. The speed of light in a vacuum is always constant at approximately 299,792,458 meters per second. However, when light travels through a medium such as air or water, it can appear to slow down due to interactions with the particles in that medium.

This phenomenon is known as refraction and is caused by the change in the speed of light as it passes through different materials. This change in speed is due to the interaction between the photons and the particles in the medium, which causes the photons to change direction and slow down.

As for the question of why the speed of light does not slow down to nothing during its journey from the edge of the Cosmos to our eyes, it is important to understand that the vacuum of space is not truly empty. It is filled with various particles and energy emissions, but these are so spread out that they do not significantly affect the speed of light.

In summary, the speed of light is constant in a vacuum and can appear to slow down in different materials due to interactions with particles. However, these interactions are not significant enough to drastically change the speed of light during its journey through space.