The discussion centers around the nature of photons, specifically addressing how they can exist without mass while still exhibiting particle-like behavior and influencing other particles with mass. Participants explore concepts related to thermal energy, electromagnetic radiation, and the duality of light, considering both theoretical and conceptual implications.
Participants express multiple competing views regarding the nature of photons, their classification as particles, and the mechanisms of energy transfer. The discussion remains unresolved with no consensus on these points.
Participants highlight limitations in understanding due to the complexity of quantum mechanics and the nuances of terminology used in physics education. There are references to the need for further clarification on the definitions and behaviors of photons.
mvbn said:For example, thermal energy exists and has no mass, but is carried by particles which have mass.
As davenn wrote, electomagnetic radiation is how I would consider thermal energy 'travels'. You may be speaking about kinetic energy when you mention particles that have mass, as in the collisions of molecules in a gas or their vibrations in a solid.mvbn said:For example, thermal energy exists and has no mass, but is carried by particles which have mass.
Photons are best thought of as the minimum amount (quanta) of light that can be transferred. You will read that light/photons exhibit a "wave/particle duality", but the experts will tell you this is an analogy, and it's better to think of photons as neither (they are their own unique, quantum object.)A photon is described as a particle
Light travels as electromagnetic waves - an excitation of the EM field.how can a photon exist on its own, travel in space
Light has energy and momentum. The E=mc^2 equation from Einstein that most folks are familiar with explains the relationship between energy and mass. But there is more to the right hand side of the equation that's frequently omitted - a momentum component for massless particles. The equation reduces to the simpler E=mc^2 when the momentum term iz zero. So light does indeed exert a pressure, albeit ever so small, from the momentum it carries.and even push other particles with mass if it has no mass itself?
I thought When One vibrating particle(atom) hits another vibrating particle and causes it to vibrate more that is transfer of thermal energy without photons. Am I wrong?.davenn said:radiated thermal energy is carried by infrared photons ( more precisely IR Electromagnetic radiation) massless particles <-- and I use that term broadly
http://en.wikipedia.org/wiki/Thermal_radiationmvbn said:I thought When One vibrating particle(atom) hits another vibrating particle and causes it to vibrate more that is transfer of thermal energy without photons. Am I wrong?.
Light has particle properties. Photons are particles.mvbn said:It says clearly that it is "elementary particle" and not just have particle properties.
You are not wrong. This is an example of conduction. There are additional ways to transfer heat. One, as A.T. pointed out, is radiation.mvbn said:I thought When One vibrating particle(atom) hits another vibrating particle and causes it to vibrate more that is transfer of thermal energy without photons. Am I wrong?.
A.T. said:Light has particle properties. Photons are particles.
bhobba said:Well first a correct analysis with photons really needs QED (Quantum Electrodynamics) since the photons are actually excitations of an underlying EM field... ...if they were actually quantum particles in the usual sense, which is the usual way its treated in beginning treatments - its wrong - but we all must start somewhere.
^ Excerpt from PF FAQ: "Is Light A Wave Or A Particle?"ZapperZ said:We still use the “duality” description of light when we try to describe light to laymen because wave and particle are behavior most people are familiar with. However, it doesn’t mean that in physics, or in the working of physicists, such a duality has any significance.