It's a poll, there seems to be some confusion from members as to whether or not photons possess mass. I believe they do, others say they do not. What do you think?

like everything that travels at c it has no mass those that travel below c have mass and those that travel above c have negative mass

It's a poll, there seems to be some confusion from members as to whether or not photons possess mass. I believe they do, others say they do not. What do you think?
You believe they do? Why?

In order to move in space the object must have some mass to propell it, thus Singularity seems to agree :L

Photons have no "rest mass", but any object with energy will have some mass due to E=mc^2. You can rearrange that equation to solve for "m" and get the mass of a photon if you know its energy.

In order to move in space the object must have some mass to propell it, thus Singularity seems to agree
WTF? How do you work that out?
And Singularhilarity's agreement means rien - nul - zero. She's already demonstrated a worse grasp of physics than my dead hamster has.

WTF? How do you work that out?
And Singularhilarity's agreement means rien - nul - zero. She's already demonstrated a worse grasp of physics than my dead hamster has.

Your grasp is clearly evident in this thread :D

http://sciforums.com/showthread.php?t=66484

Oh you mean you STILL fail to understand? Never mind, presumably once you develop a second brain cell you'll learn to read and take in what's being said. Instead of just asking one inane question after another.
And re-read that post - I never mentioned MY grasp of physics... merely yours and that of my dead hamster.

Oh you mean you STILL fail to understand? Never mind, presumably once you develop a second brain cell you'll learn to read and take in what's being said. Instead of just asking one inane question after another.
And re-read that post - I never mentioned MY grasp of physics... merely yours and that of my dead hamster.

:D ;) :cool:

Does my lonliness have mass :shrug:

I say no...lonliness does not have mass.
Neither do photons.

Like Gravity I don't think there is anything to detect.. as far as matter is concerned...I believe it is an effect. And I believe that we are viewing this effect on the fabric of space or virtual particles....just like gravity is an effect of matter I believe light is an effect of energy ...almost like a reflection of energy off particles as it travels...thus it's seemingly dual nature.

Start a thread on that Saquist.

that would take time to formulate the premise accurately with the propper sourse data...I don't have that time at current.

Sounds very interesting.

Some here seem to think light does have mass, so who is correct?!

Sounds very interesting.

most people's perception of light and gravity is shaped by the thought that both travel through a vaccuum.

However Einstein made a mathematical allowance for virtual particles.
Imagine two particles come into existence simultaneously. They are oppositely charge. matter and antimatter. But just as quickly as they appear. They ahnhialate each other.
Virtual particles litteraly may occupy every square micron of the universe. It may be the very "fabric" of space that we've often referred to.
Some call this effect "quintessence."

Both Gravity and Light need a medium to transfer their respective forces...EM and Gravity.

The question is do we take into account the true effects of light and Gravity as they travel accross this "fabric of space."

The most fascintating thing about this premise is the by observing light as it appears to produce waves and particle maybe that we are actually seeing virtual particles themselves...in a way.

the theory of general relativity explains exactly this question, thats what made einstein famous, in my opinion it is questionable still and could be contested in the future when we have a greater understanding of the universe.


peace.

How would you calculate a photons (rest)mass? You cannot being the velocity & momentum down to zero to calculate (e/c2). Thus it has no mass.

Just because you can't calculate something doesn't mean it's 0

Since the calculation is possible...
Look at it the other way. If it had any rest mass then relativistic effects would increase its mass to infinity at light speed.
And since photons (by definition) travel at light speed the rest mass MUST be zero.

ok, now I concur :L it is sad though..

They're like me... no mass... no point

Some here seem to think light does have mass, so who is correct?!

The ones that think light has mass are ready for the funny farm, as to date
every experiment has shown that light has NO mass, heck i think i will start my own funny farm, plenty of customers here :D

photons do have mass it is so small however that some people neglect it. photons mass is less than 10^-51 g...but not 0.

photons mass is less than 10^-51 g...but not 0.
Not necessarily. That figure of 10^-51 g is the upper limit of possible mass,
http://engr-sci.org/pnu/2003/split/625-2.html
A new limit on photon mass, less than 10-51 grams or 7 x 10-19 electron volts, has been established by an experiment in which light is aimed at a sensitive torsion balance; if light had mass, the rotating balance would suffer an additional tiny torque. This represents a 20-fold improvement over previous limits on photon mass.

Photon mass is expected to be zero by most physicists, but this is an assumption which must be checked experimentally. A nonzero mass would make trouble for special relativity, Maxwell's equations, and for Coulomb's inverse-square law for electrical attraction.
My italics.

Start a thread on that Saquist.

I already did , but some moderators dont like the truth to be out so it was moved to pseudoscience, I hope they close it so that i will move on to a new science forum somewhere on internet, so there is still some hope for this forum left , i think.

http://sciforums.com/showthread.php?t=66484

I already did , but some moderators dont like the truth to be out so it was moved to pseudoscience, I hope they close it so that i will move on to a new science forum somewhere on internet, so there is still some hope for this forum left , i think.

http://sciforums.com/showthread.php?t=66484


dont leave the forum, or i will start to look like the nut.


peace.

dont leave the forum, or i will start to look like the nut.


peace.

U r a god fearing person but u have started picking up, i dont mind alliance with theists if they want to fight the psuedoscience. :shrug:

maybe a foton needs a higgs boson to give it rest mass

maybe a foton needs a higgs boson to give it rest mass
??? Photons do not have rest mass, if it had rest mass it wouldn't BE a photon.

Just because you can't calculate something doesn't mean it's 0


The very, very best experiments have failed to give photons a mass, if
photons do have mass, no matter how miniscule, science will have to be re written.

It depends on how fast it's traveling.

The very, very best experiments have failed to give photons a mass, if
photons do have mass, no matter how miniscule, science will have to be re written.

Nice try Mr. illuminati.

http://upload.wikimedia.org/wikipedia/en/thumb/1/1d/Crookes_radiometer.jpg/180px-Crookes_radiometer.jpg

http://en.wikipedia.org/wiki/Crookes_radiometer


http://en.wikipedia.org/wiki/Radiation_pressure



http://upload.wikimedia.org/wikipedia/en/f/f7/Solarsail_msfc.jpg

http://en.wikipedia.org/wiki/Solar_sail

Nice try Mr. illuminati.]

Ok, you win, now explain a universe with a massive photon :p

They have energy. Energy is mass.

They have energy. Energy is mass.

If any one, can give a theory of how the universe works with a massive photon i would be more than pleased to read it, come on guys, it is time to put up or shut up, and i really mean i would be interested.

If any one, can give a theory of how the universe works with a massive photon i would be more than pleased to read it, come on guys, it is time to put up or shut up, and i really mean i would be interested.

Stop trolling and stick to the topic, if u want to discuss about some your imaginary massive xyz then start another thread on that topic, hijacking a thread can get u infractions.

Singularity:

Crookes' radiometer and solar sails show that light has momentum, not that is has mass.

Hope this clears up the confusion.

They have energy. Energy is mass.

Incorrect statement. Even though one can be converted into the other, that's a long way from being the same thing.

Singularity:

Crookes' radiometer and solar sails show that light has momentum, not that is has mass.

Hope this clears up the confusion.

So which book should i read that explains how / what holds momentum without mass ?

Try some of Dick Feynman's books,
I can't remember which ones would be most useful (and I'm not posting from home so I can't check my bookshelves), but
QED, Six Easy Pieces, Six Not So Easy Pieces, etc. are all immensely readable.
http://www.amazon.com/s/ref=nb_ss_gw/102-5925216-6001722?url=search-alias%3Daps&field-keywords=feyman&Go.x=0&Go.y=0&Go=Go

Oops, I thought I ticked no.

Wally. :D

Don't photons sort of have mass because they're traveling so gosh darn fast?

Singularity:

So which book should i read that explains how / what holds momentum without mass ?

Any book that has an introductory section on Special Relativity should do the job.

But I can explain it briefly right here for you. Start with Einstein's energy equation:

E^2 = (pc)^2 + (mc^2)^2

Now. Consider a photon, with no (rest) mass, so that m=0 in the above equation. Then, the equation reduces to E = pc, or p=E/c. p is the photon's momentum, which is related to its energy. Notice that it has momentum even though its mass is zero.

Roman:

Don't photons sort of have mass because they're traveling so gosh darn fast?

No.

Wouldnt they have to have SOME mass, no matter how infinitesimal, in order to be effected by gravity?

That's my arguement, and I'm stickin' to it.

~String

Wouldnt they have to have SOME mass, no matter how infinitesimal, in order to be effected by gravity?

That's my arguement, and I'm stickin' to it.

~String

Fortunately the polls are showing some good signs these days, in the past it would had been 1:14.

Photons have mass hence all those wrong formulaes should be corrected.

Wouldnt they have to have SOME mass, no matter how infinitesimal, in order to be effected by gravity?

That's my arguement, and I'm stickin' to it.

Well, a photon mass isn't experimentally ruled out, but giving the photon a mass would change some of the most well understood physics in the history of the subject. QED is shown to be more accurate than any thoery we have ever developed.

A few arguments:

The first one is easy---they move at the speed of light, and nothing that moves at the speed of light is impossible if it has mass.

This is a first answer. It is a bit circular (photons are massless because they move at the speed of light, and they move a the speed of light because they are massless), and one may object that the photon can have a tiny mass and move at CLOSE to the speed of light. Fine.

The second answer is if the photon had a mass, the force which it mediates would be a short range force, with a range proportional to the compton wavelength of the photon. Plug in some #'s, using a range of 1000 meters:

\lambda=\frac{h}{mc} \rightarrow m=\frac{h}{c \lambda}

Then

m \sim \frac{10^{-34}}{10^8 10^3}\sim 10^{-45} kg,

which is about 14 orders of magnitude smaller than an electron's mass. We could improve this bound by testing electromagnetism to longer distnaces, but gravity starts to dominate pretty quickly, so that's pretty much out.

Because the photon mass would have to be so incredibly small, we would say that it would represent a tremendous fine tuning. Fine tunings can be understood in a variety of ways, but think of it like this... Suppose a computer is generating random numbers for you, and all of them are around 1---like 1.1, 0.8, 1.5, 1.3, ... Then, all of a sudden a number pops up which is 10^-15. Now, it's perfectly plausible that such a small number comes up---they are all random after all. But if all the numbers are around one, and one is so close to zero, you have to wonder a bit why it was so close to zero---even though you don't know how the random number generator works, you do know that there has to be a reason why it spit out, say, 30ish numbers that were around 1, and one that was really close to zero.

Finally, the way we understand forces in physics is to have a massless mediator. If the photon is massive, then a lot of what we know about physics is patently wrong.

As for light being effected by gravity, it doesn't need to have a mass.

Read this article by John Baez:
http://math.ucr.edu/home/baez/physics/Relativity/SR/light_mass.html

Don't photons sort of have mass because they're traveling so gosh darn fast?

The exact opposite:)

Wouldnt they have to have SOME mass, no matter how infinitesimal, in order to be effected by gravity?

That's my arguement, and I'm stickin' to it.

Obviously, you're not serious. An argument based on nothing other than wishful thinking is worthless.


Fortunately the polls are showing some good signs these days, in the past it would had been 1:14.

It's a good thing science isn't decided by polls of non-scientists.

Photons have mass hence all those wrong formulaes should be corrected.

Unfortunately, contrary to superstring99, I'm afraid that you are serious.

Do you think wishful thinking makes it so?

Obviously, you're not serious. An argument based on nothing other than wishful thinking is worthless.
...

Unfortunately, contrary to superstring99, I'm afraid that you are serious.

Do you think wishful thinking makes it so?

Since u failed to notice the bold text inside below link , i am not so serious about above comments.


Space Bending Debunked (http://sciforums.com/showthread.php?p=1387441#post1387441)

I have no idea about E = mc^2

But just curious in case of light, since light has no mass hence

E = 0 c^2

So, E = 0 ?

I have no idea about E = mc^2

But just curious in case of light, since light has no mass hence

E = 0 c^2

So, E = 0 ?

Yes, a photon at rest has no energy. Actuallty this means that a photon cannot be at rest, as for an example a proton.

I have no idea about E = mc^2

But just curious in case of light, since light has no mass hence

E = 0 c^2

So, E = 0 ?

The equation E=mc^2 is for an object, particle or whatever at rest. In the equation, m is the rest mass and E is the rest mass energy.

Photons are never at rest, so the equation just doesn't apply to them. Instead, use the one I gave above.

The equation E=mc^2 is for an object, particle or whatever at rest. In the equation, m is the rest mass and E is the rest mass energy.

This is one of the things that really piss me off for some reason---people claiming that the photon has mass JUST because they accept the validity of the mass-energy relationship. These people don't know where this formula comes from, or why it applies, they just blindly apply it and think themselves more intelligent than those who couldn't see that such a simple-minded application of a formula proves physics wrong.

Do you really think that in the 100 years since we came up with this formula that no one has thought that it implies a photon has mass? Do you think that you're more intelligent that the four generations of Nobel Lauriates who have thought about these problems?

I even had one guy who pointed out that a photon has no rest mass, but because momentum is given by mass x velocity, and the velocity of the photon was c, then p = mc. This, of course, recovers E=mc^2 when you substitute it into the equation, regardless of the fact that you have assumed BOTH a massless and massive photon at the same time!

Ugh. I wish people would read more.

This is one of the things that really piss me off for some reason---people claiming that the photon has mass JUST because they accept the validity of the mass-energy relationship. These people don't know where this formula comes from, or why it applies, they just blindly apply it and think themselves more intelligent than those who couldn't see that such a simple-minded application of a formula proves physics wrong.

Do you really think that in the 100 years since we came up with this formula that no one has thought that it implies a photon has mass? Do you think that you're more intelligent that the four generations of Nobel Lauriates who have thought about these problems?

I even had one guy who pointed out that a photon has no rest mass, but because momentum is given by mass x velocity, and the velocity of the photon was c, then p = mc. This, of course, recovers E=mc^2 when you substitute it into the equation, regardless of the fact that you have assumed BOTH a massless and massive photon at the same time!

Ugh. I wish people would read more.


Generally I am under the impression that you think most other people are morons.:bugeye:

Generally I am under the impression that you think most other people are morons.:bugeye:

I strongly disagree. It's just the undereducated ones that want to TELL rather than ask and learn.

well its the impression I get, also from other threads, I may be wrong of course. In any case, those who are undereducated should then be treated with some patience. And who exactly are" under educated"? Those without a phd?

They are treated with patience, UNLESS they spout rubbish caused by not understanding as if were the reality.
It's the "I thought of this and everyone else is wrong" declarations that get slapped down.

And who exactly are" under educated"? Those without a phd?
Nope, just those that read half of what they should and understand less than half of what they've read, then make ridiculous assertions rather than asking for clarification.

Well we agree then :-)

im kind of missing something here, i have been doing some research about photons at rest and cant see how a photon actualy can be at rest.


could somebody explain to me how a photon can be at rest in order to explain 0 mass in that state?


peace.

The way I understand it (probably wrong) is that if it did have rest mass then its mass at C MUST be infinite. Since, by definition it does C then it cannot have rest mass. If it is at rest it is no longer a photon...
I tried googling for methods on determining the rest mass (loads of stuff on the actual results...) and either have to pay money for the papers or find stuff that I have to pay and can't follow :D
A rotating torsion balance method is used to detect the product of the photon mass squared and the ambient cosmic vector potential Ae. The signal is modulated by rotating the torsion balance to ensure the effectiveness of detection for all possible orientations of the vector potential. The influences of sidereal disturbances of environment are also removed by virtue of this modulation method. The experimental result shows μγ2Ae<1.1×10-11   T m/m2, with μγ-1 as the characteristic length associated with photon mass. If the ambient cosmic vector potential Ae is 1012   T m due to cluster level fields, we obtain a new upper limit on photon mass of 1.2×10-51   g.
From http://prola.aps.org/abstract/PRL/v90/i8/e081801
Maybe JamesR or someone can explain it better, but that's a simple explanation.

:(

Do they have mass or not?

Nes.

Why is this a poll? Are photons going to change their nature if a enough Internet loons vote yes?

The list of 'yes' voters doesn't surprise me at all. The poll might as well be titled 'I was goofing off in science class'

Are photons going to change their nature if a enough Internet loons vote yes?
Duh. Of course it's going to change as a result of the poll.
Then we'll have a poll on "Do aliens exist?", "Do I need a head to stay alive?", and finally "Can DarksidZz get a woman?"

I should have voted no. In my haste I forgot that E = mc^2 refers to rest energy and rest mass. I wish I could change my vote, because now I look stupid on this public poll. :o

So, do you want mayo with it or not? :D

Yes, a photon at rest has no energy. Actuallty this means that a photon cannot be at rest, as for an example a proton.

So can we create in theory a Perpetual Motion Machine that generates energy due to this nature of Photon ?

I mean http://en.wikipedia.org/wiki/Radiation_pressure

Probably not. The practicalities are that anything large enough to catch enough photon pressure to be worth using as an output would be too large to turn (especially in a gravity field).

Hi bsemak---

Just people who think they know more than I do, without having actually studied the problems in any detail. People who claim that a photon has mass just because of a blind application of a formula which doesn't apply. People who claim to "explain" things without doing anything more than metaphysics.

Yes, these people are morons.

I will always treat people with respect and patience untill they show me that they are unwilling to learn. I have no patience for such people.

Hi bsemak---

Just people who think they know more than I do, without having actually studied the problems in any detail. People who claim that a photon has mass just because of a blind application of a formula which doesn't apply. People who claim to "explain" things without doing anything more than metaphysics.

Yes, these people are morons.

I will always treat people with respect and patience untill they show me that they are unwilling to learn. I have no patience for such people.

And I'm exactly the same way. As I've said before, the realization that you don't know something is the first sign of intelligence. And the second sign is asking questions in order to learn.

But far too many cannot resist opening their mouths and spewing nonsense. That's the first indication of ignorance and/or stupidity.

so how do we measure the rest mass of a photon what tests do we conduct?


peace.

so how do we measure the rest mass of a photon what tests do we conduct?


peace.

You don't. How does one measure the rest mass of a thought, too? :D

You don't. How does one measure the rest mass of a thought, too? :D


if it cannot be tested how can we believe it as fact yet :bugeye:. can we observe it atleast?

i dont know the science behind the mass of a thought i havent looked into it to be honest so i wont comment just yet,


peace.

If the photon had a non-zero rest mass, Coulomb's Law would have to have terms in addition to the 1/r^2 term. This means the rest mass of the photon can be measured to within some experimental error, which is currently around 1e-49 grams.

Hi DH---

You are right, but it could be that the terms are so small that we can't measure them. See my previous posts about the Compton wavelength of the photon that has a very small mass.

In this post http://www.sciforums.com/showpost.php?p=1391396&postcount=48, I did a back of the envelope type calculation to put a bound on the photon mass. What I forgot was that one can actually do much better. The van Allen belts are the magnetic fields which surround the Earth, to several thousand kilometers (from the center of the Earth). This is another three or four orders of magnitude, I think. Maybe 10^-48 kg?

so how do we measure the rest mass of a photon what tests do we conduct?

Chi---I just showed you how---look at the Compton wavelength.

And I'm exactly the same way. As I've said before, the realization that you don't know something is the first sign of intelligence. And the second sign is asking questions in order to learn.

What ever happened to you just reading posts?

What ever happened to you just reading posts?

What reason do you have to try to pick a quarrel with me, Ben? :shrug: I've shown you nothing but respect and I think I've always agreed whith what you said. Better than 95% at the very least.

And to answer the question directly, I now have more time to spend than previously.

You don't. How does one measure the rest mass of a thought, too? :D

Thoughts don't have rest mass, but they can have weight and momentum. Some thoughts carry a great deal of weight and momentum, while others carry zero weight, thus zero momentum. Now as far as which is which, that is relative as to whom is doing the measuring. :D

Thoughts don't have rest mass, but they can have weight and momentum. Some thoughts carry a great deal of weight and momentum, while others carry zero weight, thus zero momentum. Now as far as which is which, that is relative as to whom is doing the measuring. :D

Ha, ha, ha! Very well said!! :D

What reason do you have to try to pick a quarrel with me, Ben? I've shown you nothing but respect and I think I've always agreed whith what you said. Better than 95% at the very least.

Sorry Read-Only. Maybe I should have written "What ever happened to you just reading the posts? :)"

No quarrels---I should point out that I, too, once thought that I would just read the posts here:)

http://C:\Documents and Settings\lui bei\My Documents\My Pictures\f234e8201fbf9135259fef7f15ab29c9.png

So which book should i read that explains how / what holds momentum without mass ?
You could try any book on electrodynamics. Search for the Poyinting vector

I have no idea about E = mc^2

But just curious in case of light, since light has no mass hence

E = 0 c^2

So, E = 0 ?

No, the correct equation (I suggest that you read any introductory book on relativity) is E^2 = p^2c^2 + m^2c^4.
For light, E = pc.

Try to find using the 2 equations what is a photon's mass (Hint: replace in the first equation E with pc)