Couldn't we just run a photon(s) back and forth between 2 mirror paddles to create energy? Since light essentially has infinite energy couldn't we put that to use somehow? I got this idea from a light clock, where a photon goes back and forth between 2 mirror paddles to calculate time.
Oops, yeah a photon. Please Register or Log in to view the hidden image! Well General Relativity says that to go at the speed of light you would have to have an infinite amount of energy. Which means obviously light must.
Hi Kneel, Welcome to SciForums. Light does not have an infinite amount of energy. It would take an infinite amount of energy to accelerate a massive particle to the speed of light, but photons neither accelerate nor do they have mass, so this idea does not apply. Another way to see that photons do not have an infinite amount of energy is to consider the photoelectric effect. The binding energy of an electron to its atom is finite and the kinetic energy of an ejected electron is also finite. The energy of the original photon is equal to the sum of the binding energy and the kinetic energy, so it too is finite. Otherwise energy would not be conserved. Also, if the energy in a photon were infinite then we would have to live in absolute and total darkness in order to avoid incinerating the world. -Dale
Light does not have infinite energy because light is not matter. Light is a wave, like soundwaves and microwaves, which function on a frequency and density much higher than matter. Matter cannot move faster than light, but light can move faster than light.
Just to comment... Microwaves are light waves, just at a different wavelength than visible light. However, sound waves are different. Light waves can propagate in a vacuum. However, sound waves require a vibration of molecules to propagate. In addition, as far as we have found so far, only the group velocity of light waves move faster than light. Nothing that can carry information can move faster than light.
The bolded clause is true. Well done on getting something right! (Shame about the rest Please Register or Log in to view the hidden image! )
Light has mass, and exerts some light pressure on the Earth. I think this is what powers a solar sail. It's very small, though. Better to use it to generate electricity.
correct, it does not apply. for light, P=h/lambda=E/c although, you should not think of it as mass approaching zero and velocity approaching c. that may lead to mistakes.
Correct, the relativistic definition of momentum is p = γmv. As v->c γ->infinity, so for particles moving at c momentum can only be finite if m=0. -Dale
every time a photon is obsorbed.... the electron that obsorbed it, moves... its orbit gets alittle bigger,, generally... and this... motion, cause other electrons to move. that is why when that same electron re-emits that photon, it will have slightly less energy than it did when it was first abosrbed... thats called entropy. (literally, the designed loss of the universe.) all interactions... result in this bleeding out of energy as random motions on bodies manifesting as heat.) the photons them selves do bounce AROUND.... but a blue light photon for example is worth about 5 eV or so.... thats about 1.60202*10^-19 joules... each time it is absorbed, and emitted, it is less energetic... and thus, instead of 5... it now only has 4.5 eV... then 4 ... then 3.5.. then 3.. then 2.5.... then 2... then 1..5... then 1.... then... as its energy level drops down below one eV... and this is where the then now, (used to be blue) less energetic... RED photons.. transitions into becoming radiant heat.... INFRA-RED... it become invisible, and as heat it becomes ever and ever more cool.... as the photon itself converts down into nothingness.... ending up as some average typical bottom range where by all the energy is disipated and lost. like burning in hell... thats what entropy is... dont ever let anyone tell you that your soul is made of light....!! because if it is... your soul is doomed to dissolve into heat. -MT
Be warned: MT in post just made is tossing around terms as if he understood them. The radiation from a gas is set by the difference in the energy levels (a fixed value for each isolated atom, not changing to ever lower values as he suggests numerically). The radiation by a solid (or liquid) is a continuium, set by the temperature and the emissivity of the solid surface. He is quite confused but partially correct about entropy.
why dont you point out my errors....???????????? instead of saying,, publically.... beware of moshehs posts... but he's right about entropy. what kind of shit is that..??????????????????????????? you want to warn people about me, but in the next paragraph, you admit i am correct in my statements.... you hypocrite yourself.... and it sickens me. dont pick on me, unless i have made a real error... in which case.. educate me, and i will appreciate it. to warn people, that they should have caution when reading my posts, is an insult. -MT (and your post, was anything but clear.....) (sure atoms obsorb, only specific lines, in a spectrum, but that does not make anything i said... untrue... only unclear.) ( if you wish to further clarify my post... then that is helpful...) ( but to warn the masses as to my truth, is nothing but insulting.)
Billy T: Thanks, you bring reason to the confusion. Edit: And Pete and Dale and some I may have missed.
