Slowing Photons: A Look at Light Speed Rockets & Measuring Slower Speeds

[CBR600RR]

How can a photons velocity be slowed down when they pass through air, water, etc? If photons can be slowed down to slower than light speed, then would it not be possible for a "futuristic lightspeed rocket" to catch up to a photon? And also how can someone measure a slower speed (other than the speed of light) for a photon if special relativity states that all observers must measure the exact same speed of light? What am I missing?

 

[jtbell]

How can a photons velocity be slowed down when they pass through air, water, etc?

See the following posting in the Physics Forums FAQ:

https://www.physicsforums.com/showthread.php?p=899393#post899393

 

[Entropia]

Slowing down photons is a complex concept that involves the interaction of photons with the medium they are passing through. In general, the speed of light in a vacuum is considered to be the fastest speed possible, and this speed is denoted by the letter 'c'. However, when photons pass through a medium such as air or water, they interact with the particles in the medium and can be temporarily absorbed and re-emitted, which causes a delay in their overall speed. This delay is what we perceive as the slowing down of light.

It is important to note that this slowing down is only temporary and the photons will eventually reach their original speed once they leave the medium. This is because the absorption and re-emission process is a continuous one, with photons constantly being absorbed and re-emitted by the particles in the medium.

As for your question about a "futuristic lightspeed rocket" catching up to a photon, it is important to understand that the speed of light is still the ultimate speed limit in the universe. No matter how advanced our technology becomes, we cannot surpass the speed of light. This is a fundamental principle of special relativity.

Regarding the measurement of slower speeds for photons, it is true that special relativity states that all observers must measure the exact same speed of light. However, this applies to the speed of light in a vacuum. When light passes through a medium, its speed can vary and can be measured by different observers. This is because the speed of light in a medium is dependent on the properties of that medium, such as its density and refractive index.

In conclusion, the concept of slowing down photons is a complex one and involves the interaction of photons with the medium they are passing through. While it is possible to temporarily slow down photons, the speed of light in a vacuum remains the ultimate speed limit in the universe.