Pressure of Light Moves Liquid

[LJP07]

Scientists have figured out how to create a jet of liquid with nothing but the power of light: :)

 

LiveScience.com - Pressure of Light Can Move Liquid

 

 

 

 

[LJP07]

As I was reading this, I get a little confused, I understand that light is massless, but it moves at the speed of light:

 

E=MC2, but if light is a form of energy, it must multiply by something to be counted as energy as E = (0)(Light)2, this means E=0, so there is no energy yet light is a form of energy, can this be true, I'm missing something?

 

Is this type of intrinsic mass, where it's the momentum and energy and it's frame of reference {(mc)2 = E2 - (pc)2} are taken into account?

[Jay-qu]

Light has a momentum, but doesnt have a mass - the momentum = h/lambda. It doesnt have anything to do with mv - so its useless to try and calculate a value for the mass of a photon, because like you said - its massless. Also the energy of a photon can be calculated by E=hf.

 

Interestingly the equations are consistant if you persist in calculating a mass for the photon:

 

mv=h/lambda

m=h/(lambda*c)

 

E=mc^2

E=(h/(lambda*c))c^2

E=hc/lambda

E=hf