Does Light Have Mass?

[ogmsband]

me and my friend are in an ongoing argument about whether or not light has mass and i thought i would put it on here to these what you guys think.

[gtrick69]

yes it does!!! how do you think plants do photosynthesis, light has protons in it =] which have to have mass, being a stoner i tend to think bout these things alot haha

[arelik]

Light is made of photons. I looked up 'photon' in Wikipedia and it said it has zero invariant mass.

[nitmachine]

Light does not have mass. Special Relatively provides equations that relate mass to velocity, in the form:

m(v) = m(stationary)/sqrt(1 - (v/c))

where m(stationary) is the mass of the object when it is stationary, v is the velocity of the object, and c is the speed of light. According to this formula, when v = c, or when an object is moving at the speed of light, it's mass will be it's stationary mass divided by zero, which is undefined. The limit of this equation as v->c is infinity, or, in other words, the mass of an object increases without bound as its speed approaches that of light.

Now, clearly, photons, which are the particles of light, move at the speed of light. Therefore, if they had any mass at all, that mass would be infinite. Therefore, Special Relativity tells us that photons are massless.

[Engler]

Yeah, light DOESN'T have mass. Know wonder this guy is a stoner.

[gtrick69]

wow...=] thats kool to know. good question

[ogmsband]

it has no invariant mass i see but how about relativistic mass which is the mass associated with the theory of objects get more mass as they go faster, what I'm finding just keeps going in circles.

[Tenniswrestler]

i think this is a question to ask ur science teacher... thats probably the most reliable source

[gtrick69]

how do i get my stats as my signiture? i tried puttin the code there but then it just shows the code instead of the blue box...what am i doin wrong? oh and it seems like somthing would need mass to start with in order to gain mass with speed, but idk =p

[RandomPscho]

This is Critical Thinking!!!

it has no invariant mass i see but how about relativistic mass which is the mass associated with the theory of objects get more mass as they go faster, what I'm finding just keeps going in circles.

If the thing in question, photon in this case, has no mass to begin with, it will not gain any.

[ogmsband]

Originally Posted by Tenniswrestler

i think this is a question to ask ur science teacher... thats probably the most reliable source

i have asked him many different questions on this subject and he has no idea

[Engler]

Originally Posted by Tenniswrestler

i think this is a question to ask ur science teacher... thats probably the most reliable source

No. What do science teachers know? Clearly the best place to get a good answer is a dance simulation website's forums. Duh, when were you born, yesterday?


^rainbow of sarcasm

[ogmsband]

Originally Posted by Engler

No. What do science teachers know? Clearly the best place to get a good answer is a dance simulation website's forums. Duh, when were you born, yesterday?


^rainbow of sarcasm

well damn i thought out of the 1.2 million people here might now what they were talking about.

[three17s]

[ellabella20]

The short answer is "no", but it is a qualified "no" because there are odd ways of interpreting the question which could justify the answer "yes".

Light is composed of photons, so we could ask if the photon has mass. The answer is then definitely "no": the photon is a massless particle. According to theory it has energy and momentum but no mass, and this is confirmed by experiment to within strict limits. Even before it was known that light is composed of photons, it was known that light carries momentum and will exert pressure on a surface. This is not evidence that it has mass since momentum can exist without mass.

[lumphoboextreme]

Originally Posted by Tenniswrestler

i think this is a question to ask ur science teacher... thats probably the most reliable source

yeah really, my bio teacher seems to know everything. 0.o

[ogmsband]

Originally Posted by ellabella20

The short answer is "no", but it is a qualified "no" because there are odd ways of interpreting the question which could justify the answer "yes".

Light is composed of photons, so we could ask if the photon has mass. The answer is then definitely "no": the photon is a massless particle. According to theory it has energy and momentum but no mass, and this is confirmed by experiment to within strict limits. Even before it was known that light is composed of photons, it was known that light carries momentum and will exert pressure on a surface. This is not evidence that it has mass since momentum can exist without mass.

you copied that i have it printed out but its leading me in circles

[irishknight]

Well everything is made of atoms, and atoms DO have mass.. As far as I know.

[gtrick69]

light isn't made of atoms, its photons mang...which apparently DO NOT have mass so i'de say the answer is no, but originally i thought yes because a photon is SOMTHING so i just assumed it had a lil' amount of mass but guess not

[ellabella20]

I know.