Genecks Posted February 27, 2010 Posted February 27, 2010 Is there a limit to how fast a photon can travel in relation to another photon? If so, can it be considered that a photon is never at its maximal speed? I'm looking for a layman explanation.
Cap'n Refsmmat Posted February 27, 2010 Posted February 27, 2010 Assuming we don't mix reference frames, all photons should travel at exactly the same speed. (Also assuming they're traveling through the same medium.)
Mr Skeptic Posted March 1, 2010 Posted March 1, 2010 Well, if you have two photons traveling in opposite directions, you just add their velocities together like so:http://en.wikipedia.org/wiki/Velocity-addition_formula So, they travel at c in relation to each other, even though from our reference frame it naively looks like it should be 2c. This formula seems to work, despite the fact that photons aren't supposed to have a reference frame. Hmm.
Sisyphus Posted March 1, 2010 Posted March 1, 2010 (edited) This formula seems to work, despite the fact that photons aren't supposed to have a reference frame. Hmm. Adding C to anything will get you an answer of C, though. So from the "photon's frame," everything would be moving at C relative to it, meaning objects and photons in the same direction would have zero relative velocity, etc. In other words, it breaks down. Edited March 1, 2010 by Sisyphus
Mr Skeptic Posted March 1, 2010 Posted March 1, 2010 That's what it's supposed to do though. However with speeds larger than c it does give weird results, but then we don't actually observe speeds larger than c.
Genecks Posted March 3, 2010 Author Posted March 3, 2010 (edited) Ok, so to go faster than light, an object would need to be encapsulated by a medium that allows it to go faster than light and travel through/within said medium? Hmm. As such, scientists currently consider the best medium to be a vacuum? Alright. But isn't a vacuum hypothetical? I think I see why scientists say it's impractical for something to go faster than the speed of light. But I don't think it's impractical to not enable an object to go the same speed as light. I think I'm starting to see why a lot of people have been arguing about in the past few decades. Edited March 3, 2010 by Genecks
michel123456 Posted March 3, 2010 Posted March 3, 2010 Motion includes 2 concepts: space & time. As much as i know, a photon do not experience time, so the "moving" concept is unknown to a photon.
Bob_for_short Posted March 3, 2010 Posted March 3, 2010 If we speak of a transparent medium, glass, for example, two photons (waves) of different frequencies ω1 and ω2 may propagate with different velocities due to n(ω) < 1. The light velocity in vacuum c is the maximum possible for a wave. In a tarnsparent medium with a variable n(r,ω) the wave may accelerate and decelerate - its wavelength λ(r,ω) may vary with r. This is well known in the optical waveguides.
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now