Unraveling the Mystery of Photon Mass and Its Interplay with Gravity

[Eepl]

A photon isn't supposed to have mass. But yet it is effected by gravity. So this means that a photon must have the gravitational property. And this would give it mass. So why does gravity bend the curve of a photon? And please give me more than "gravity bends the spavetime continuum, so it effect the curve of the photon". Cause as I see that, bending in spacetime in towards a massive object would push the photon away. Cause there would be more "preasure", if you will, closer to the massive object, therefore pushing the photon away. And in that case, wouldn't you age slower on a still massive object then you would being still in space?

 

[Ambitwistor]

Originally posted by Eepl
So why does gravity bend the curve of a photon? And please give me more than "gravity bends the spavetime continuum, so it effect the curve of the photon".

But in general relativity, that's the correct answer.

Cause as I see that, bending in spacetime in towards a massive object would push the photon away.

Why? It doesn't push away other objects, like electrons or planets. Why should it push away photons?

Cause there would be more "preasure", if you will, closer to the massive object, therefore pushing the photon away.

I don't know what you're talking about. Spacetime curvature isn't pressure.

And in that case, wouldn't you age slower on a still massive object then you would being still in space?

Yes, clocks run slower on the surface of a massive body than they do far away from the body.

 

[Eepl]

Then spacetime would have to be a force, like a wave or something? Because unphysical things wouldn't be able to affect something that is physical. Like how could your imaginary friend kill your other friend. But then an object that does not have that wave type cannot be affect by the wave. So then the photon would have to have the gravitational wave type so it could be affected by spacetime. And this would give it mass.
And gravity would seem to have a physical property making it a wave type(aether), thus it would affect space. And because it affects space it in turn affects time. So time would be a wave. And the two would work together to make "spacetime" which allows us to travel through this three dimensional space. Cause with only time you're everywhere, and with only space you're nowhere. So the two together give us what we are living in right now.

sorry, long day.

 

[Eepl]

I had to reread the above before I saw that it made no sense. So I edited it. Please reread if you haven't already.

 

[Ambitwistor]

Originally posted by Eepl
Then spacetime would have to be a force, like a wave or something?

Spacetime isn't a force, or a wave. Spacetime affects things physically because it determines their geometry. (Changes in the geometry can propagate as waves, though.)

The rest of what you said didn't make much sense to me, even after your editing.

 

[Sniper__1]

spacetime itself is not real because time is not real so why don't you all be quiet about space time. Oh and the whole photon mass thing is not ecxactly untrue but things with no mass are stiil affected by mass so a photons curve is nnot unnusual at all given that time does not exist.

 

[Eepl]

Ok, so spacetime isn't a force or a wave. Then it can't directly affect physical objects. "How can your imaginary best friend kill your physical best friend?" I can't think hard then affect which way my car is going to go, so how can something that doesn't exist in reality even have a number in a mathmatical equation. My physics teacher tried to tell me that "that's just the way it works". Sorry man, won't take that. Only the physical can affect the physical. So if spacetime has no physical properties then how can it affect physical things. Like pulling in a photon. If the photon has no mass, then it has no gravity. Therefore it won't be pulled into a planet by gravity, but how can it follow the curvature of spacetime if spacetime is only an imaginary thing.

You said "(Changes in the geometry can propagate as waves, though.)" But that is after the fact. After a tragectory has been changed it will propagate a wave, but what got it to change course in the first place.

And the sum of everything else that I said was, space and time are two different wave types working together to give us three dimensional space, or spacetime. The fourth dimesion is an illusion of the resulting effect.

 

[Sniper__1]

actually you could move your car with your mind and destroy it and recostruct it into anything even solid gold STUDY QUANTUM PHYSICS!

 

[Nommos Prime (Dogon)]

Photosynthetic Absorbtion

Solar photons can add Mass indirectly to plants through photosynthesis. I know this does not endow a photon with Mass, however it does ADD Mass to a plant.

 

[Sniper__1]

really though the mass added is from the water not the solar photons they just change the mass.

 

[toe21k]

https://www.physicsforums.com/showthread.php?s=&threadid=9777 :-

Hydrogen's Mass or 'Weight' is 'negative'?

 

[wolram]

spacetime itself is not real because time is not real so why don't you all be quiet about space time. Oh and the whole photon mass thing is not ecxactly untrue but things with no mass are stiil affected by mass so a photons curve is nnot unnusual at all given that time does not exist.
--------------------------------------------------------------------
who was it that said "fools rush in where angeles
fear to tread"?
i struggle with nonintuitive theories all the time
but the bottom line is, unless one has a better
theory its all we have, many many people have dedicated
their lives trying to bring about a better understanding
of science, and many more have learned the theories
that these have people have formulated, so if you
want to ignore this wealth of information it is up to
you, maybe some of you could formulate your own
theories and re write science, when you have a theory
share it with us and we can kick it around and see
if it holds water.

 

[Ambitwistor]

Originally posted by Eepl
Ok, so spacetime isn't a force or a wave. Then it can't directly affect physical objects.

Of course this is not true. There is no law of physics that says that something has to be either a force or a wave to affect physical objects.

I can't think hard then affect which way my car is going to go, so how can something that doesn't exist in reality even have a number in a mathmatical equation.

Who said that spacetime geometry or spacetime curvature doesn't exist in reality? We can measure it, after all.

So if spacetime has no physical properties then how can it affect physical things.

As I have already said, spacetime has physical properties, namely, geometry.

If the photon has no mass, then it has no gravity.

The trajectory of an object under the influence of no external forces depends only on its initial position and velocity, and not on its mass. That's Newton's first law of motion. In general relativity, the geometry of spacetime determines what a "straight line" is, so it determines the trajectories of all bodies, regardless of whether they have mass.

You said "(Changes in the geometry can propagate as waves, though.)" But that is after the fact. After a tragectory has been changed it will propagate a wave, but what got it to change course in the first place.

If you're talking about a gravitational trajectory, it doesn't change course. It travels straight (but in a curved spacetime).

And the sum of everything else that I said was, space and time are two different wave types working together to give us three dimensional space, or spacetime. The fourth dimesion is an illusion of the resulting effect.

That may have something to do with some theory you've invented, but it has nothing to do with relativity. You should post it to the Theory Development forum.

 

[Eepl]

Sniper___1, I have studied quantum mechanics, and like Einstein I have decided that there cannot be chaos in the universe. There only seems to be chaos because our puny brains can't handle everything yet. Though this always interferes with the positivist point of view that I try to hold. But in this case it becomes religous.
Placks problem with trying to measure the speed and the possition at once was he was trying to do it on a three dimensional level. Though time adds a fourth dimesion, so the fourth dimesion could be graphed on a different three dimensional chart, put the two together and I believe that the uncertianty principle could be taken away.
Wolram,...

Ambitwistor, that thing at the very end was the start of a new theory I'm developing. And yes I will post it in the Theory Development when it's done. BUT, I have to bring up some aspects of it so I may prove my point.
You said "There is no law of physics that says that something has to be either a force or a wave to affect physical objects." Never mind about the wave thing, but all "forces" exert physical activity, thus giving it physical properties. And later you said that we can measure the curvature of spacetime, so doen't that mean spacetime has physical properties. You said that "geometery" was a physical property. Please explain that, I don't rightly understand.
More clearly what I was trying to say with the mass gravity thing was that gravity is the only force that bends spacetime, and the bending of spacetime affects only objects with mass. But to have mass you also have to have the gravitational property. So what I'm saying is for a photon to travel with the curvature of spacetime it has to work on it's level, so it would have to have the gravitational wave, which would give it mass. I figure that the mass of the photon can be calculated off the amount it curves around a massive object if the mass of the object is known and how far away the photon is.

 

[Ambitwistor]

Originally posted by Eepl
You said "There is no law of physics that says that something has to be either a force or a wave to affect physical objects." Never mind about the wave thing, but all "forces" exert physical activity, thus giving it physical properties.

Yes, but forces aren't the only things that exert a physical influence.

And later you said that we can measure the curvature of spacetime, so doen't that mean spacetime has physical properties.

Yes; that's my point. Einstein couldn't very well have developed a theory of gravity based on the properties of spacetime if those properties weren't physical.

You said that "geometery" was a physical property. Please explain that, I don't rightly understand.

Well, for example, just take a string and use it to measure the ratio of the circumference of a circle to its diameter. The geometry of space determines what that ratio will be; it doesn't have to be π.

More clearly what I was trying to say with the mass gravity thing was that gravity is the only force that bends spacetime, and the bending of spacetime affects only objects with mass.

No, the geometry of spacetime affects everything, mass or not, because everything exists within spacetime.

(And, strictly speaking, gravity is not a "force"; sometimes people call it an "interaction" when they want to be precise.)

So what I'm saying is for a photon to travel with the curvature of spacetime it has to work on it's level, so it would have to have the gravitational wave, which would give it mass.

Gravitational waves are not needed for a body to exert a gravitational influence upon another, nor do gravitational waves give bodies mass.

I figure that the mass of the photon can be calculated off the amount it curves around a massive object if the mass of the object is known and how far away the photon is.

The mass of the photon has been measured and is known to be zero, to within experimental error. But even if it wasn't known, you could not use the experiment you propose to determine its mass, because the trajectory of a test particle in a gravitational field is independent of that particle's mass: Galileo determined that as an essential property of the gravitational interaction, and Einstein built it into his theory too in the form of the equivalence principle.

 

[Eepl]

Originally posted by Ambitwistor


the geometry of spacetime affects everything, mass or not, because everything exists within spacetime.

Then you're saying that gravity directly effects the electromagnetic bubble (sorry, can't think of the right word) around the earth. As I've seen gravity can effect the particle in spacetime thus effecting the electromagnatism it produces, but never be able to effect the electromagnetic effect the particle produces directly.

Scientists say that electormagnatism travels at the speed of light (this is where I always get confused) but then you have the effects created by those electormagnetic waves.
So the path of the electromagnetic wave is c, then wouldn't the curvature of the electromagnetic wave be greater then c? And how fast does the electromagnetic effects travel through space?

 

[Ambitwistor]

Originally posted by Eepl
Then you're saying that gravity directly effects the electromagnetic bubble (sorry, can't think of the right word) around the earth.

Do you mean the Earth's electromagnetic field? Yes, it does, but not by very much. But the influence of the Earth's gravity upon electromagnetic waves has been measured.

So the path of the electromagnetic wave is c, then wouldn't the curvature of the electromagnetic wave be greater then c? And how fast does the electromagnetic effects travel through space?

Curvature is not measured in units of speed, so I don't know what it means to speak of the speed of curvature. Electromagnetic effects travel through space at c, as measured by a local inertial observer.

 

[Eepl]

I don't know enough about electromagnetic fields to argue my point well enough. Would you know of any reading material that I can use?

So they say that electromagnatism travels out like particles, but behaves like waves. This is where we get particle-wave duality. When you see a picture of a electromagnetic wave it shows the wave traveling up and down, and at 90 degree angles to it. But do those waves "emit" more waves that effect other things? Like a fish swimming though the ocean. The fish is the origin of the wave, but then waves are created from that and travel even further. And if that is, what is the speed of those waves?

 

[SmarterThanGod]

Originally posted by Eepl
"How can your imaginary best friend kill your physical best friend?"

What your missing is that spacetime is NOT imaginary. Your imaginary friend can't kill your best friend, but a car falling off a cliff due to gravity sure can. Gravity is real, and therefore, space is real. And if space is real, then time is real. Even though a photon has no mass, it is still subject to the same laws as massive objects. Space and time are both real, metaphysical dimensions. The problem is that you are all thinking of being "real" as being an object, instead of dimensions and thigns of that sort. As to the original inquiry, I believe that all particles are subject to the same laws, regardless of mass, or lack thereof.

 

[Ambitwistor]

Originally posted by Eepl
I don't know enough about electromagnetic fields to argue my point well enough. Would you know of any reading material that I can use?

What would you like to know? How gravity influences them? If so, you'd probably want to begin with the Pound-Rebka-Snyder Harvard clock tower experiment, and the gravitational deflection of light by the Sun. You can find discussions of those effects all over the place, including in any general relativity textbook. Ohanian and Ruffini is a good choice for this, and you can read summaries in Cliff Will's book or his online Living Review on experimental tests of GR. Treatments of them usually work within the semi-classical approximation of considering massless classical test particles, but you can find geometric optics approximations and such in more advanced texts like Misner et al. For a discussion of full Maxwellian electromagnetism in curved spacetime (the Einstein-Maxwell equations), you'd also want to look in an advanced GR text, such as Misner et al, Wald, etc.

When you see a picture of a electromagnetic wave it shows the wave traveling up and down, and at 90 degree angles to it. But do those waves "emit" more waves that effect other things?

No.

Like a fish swimming though the ocean. The fish is the origin of the wave, but then waves are created from that and travel even further.

In this analogy, the "fish" is a charged particle, and the water waves that are produced by its motion are the electromagnetic waves.

And if that is, what is the speed of those waves?

Electromagnetic waves travel at the speed of light. Electromagnetic waves are light.

 

[Sniper__1]

Smarter than god




TIME IS NOT REAL IT IS A MENTAL CONSTRUCT OF THE HUMAN MIND IT CANNOT "TRULY" BE MEASURED AS ENERGY OR MASS AND IT HAS NO REAL DIMENSIONS AS SHOWN IN EXPERIMENTS "TIME" DIFFERENTIATESS AND BEING THAT IT HAS NO PROPERTIES OF MATTER< ENERGY OR A CONSTANT IT IS NOT REAL! [zz)]

 

[Eepl]

So you're saying that in the 'time' that it takes for the synapsis in your brain to even phathom this subject, it's not real. Time is real. A measurement of how long it took to travel a distance in space. It's funny how something so 'fake' can be part of this reallity we call life.
I wrote something on this in the Theory Developement section under 'SmarterThanGods' last post to help him out. You might want to read what I think of spacetime.

 

[russ_watters]

Originally posted by Sniper__1
[zz)]

Yeah. That was my reaction to your post too.

You said that "geometery" was a physical property. Please explain that, I don't rightly understand.

I'll see if I can expand on what Ambitwisor said since this is a little bit tough. When talking about geometry on a flat piece of clear, flexible plastic (like an overhead projector slide), things are easy: you draw a square, you can see its a square, life is great. That's geometry of a 2D object on a 2d space. But you can't really see the space, can you (its clear)? How do you know its flat? How do you know where the edges are? - what if you don't even know if it HAS edges? That makes it tough to describe the geometry of the piece of plastic itself. Now what if you bend it? Now it is (sorta) 3 dimensional. The square you drew now looks like a rectangle in your 2d vision (your vision is a 2d projection of 3d space). But again, if you can't see the plastic itself, how would you know its bent? You know because of the geometry of square you drew on it. You know it was a square because you drew it.

This is how space works. Space is 3d curved in 4d (or something like that - I'm not sure we really know how many dimensions there are - but we can see 3 space dimensions). How do we know its curved? We know by observing the way objects behave in space. We observe light getting (apparently) bent when going near massive objects. We know that light has no mass, so how can it be affected by gravity? Well it can't - thus the apparent bending of light must actually be a bending of space itself, making the light to APPEAR to bend its path.

 

[Ambitwistor]

Originally posted by russ_watters
We know that light has no mass, so how can it be affected by gravity? Well it can't - thus the apparent bending of light must actually be a bending of space itself, making the light to APPEAR to bend its path.

If you're going to argue that massless particles aren't affected by gravity, then you have to argue that massive bodies aren't affected by gravity either. I suppose you can say that, for some weird definition of "affected by gravity", but most people would argue that gravity influences all bodies (massless or massive).

 

[Eepl]

russ_watters, thanks for trying to clear that up. But there is one thing I have learned, and that is to never try to think in 2D. Think about it. We have no real comprehension of what only 2D is. I mean could you even see in 2D? I just try to figure everything how it already is.
Has anyone ever considered that there are only two dimensions, time and space. Each could be graphed out on a x,y,z axis graph, then we would kind of have six dimensions. I mentioned this earlier with Plack's uncertainty principle. If you were to map out where a particle is in space and time sepratly then there would be no uncertainty. The exact location and velocity would be known at all times.

 

[russ_watters]

Originally posted by Ambitwistor
If you're going to argue that massless particles aren't affected by gravity...

Sorry, poorly worded. How about "attracted?"

 

[Ambitwistor]

Originally posted by russ_watters
Sorry, poorly worded. How about "attracted?"

Massless particles are attracted by gravity in the same sense that massive particles are.

 

[russ_watters]

Originally posted by Ambitwistor
Massless particles are attracted by gravity in the same sense that massive particles are.

?? A massless particle will not follow the same path past a massive object as a particle with mass would, correct? Due to a different gravitational interaction, the particle with mass will have its path bent more.

Hold a hypothetical massless particle in your hand and you feel no weight and it has no inertia if you throw it.

I don't know how you would describe that, but that's all I was trying to convey.

 

[Ambitwistor]

Originally posted by russ_watters
?? A massless particle will not follow the same path past a massive object as a particle with mass would, correct?

No, but its path is determined by its speed, not its mass. (Galileo's observation. Of course, it is true that a massive particle can't travel at the same speed as a massless one. But Galileo demonstrated --- and Einstein incorporated into his equivalence principle --- that the gravitational trajectories of two bodies are independent of their masses; they depend only on their initial speeds and locations when dropped.)

Due to a different gravitational interaction, the particle with mass will have its path bent more.

I'm not sure what you mean by "a different gravitational interaction" here ... light doesn't couple to gravity in a manner different from how matter does: they both couple through their stress-energy. And I wouldn't say that massless particles interact more weakly with gravity either ... if you shoot two planets past a star at different speeds, the slower one will have its path bent more, but that's not because the force of gravity upon it is any stronger than on the other.

Anyway, I was originally objecting to your specific statement, "We know that light has no mass, so how can it be affected by gravity? Well it can't". Even if you meant "attracted" instead of "affected", massless particles certainly are attracted by gravity.

(I said "in the same sense that massive particles are" to say that if you believe that massive particles are attracted by gravity, then for the same reasons you also have to believe that massless particles are attracted by gravity.)

Hold a hypothetical massless particle in your hand and you feel no weight and it has no inertia if you throw it.

The concepts of "weight" and "inertia" can be kind of ill-defined when you speak of light, but anyway, that doesn't really have anything to do with the particle's gravitational interaction.

 

[Eepl]

Light coming in from the sun has radiation, which effects things. The electromagnetic waves of light allows us to see. This is from the light creating chemical reactions in the back of the eye. But if a photon had no mass wouldn't it flow around the chemicles in the back of the eye. It has to create a force, a push if you will, that makes that chemical reaction. But if there is nothing to push against then nothing can move.
What I'm trying to say here is that because photons effect things with mass they themselves have to have mass. Or else wouldn't the photon flow around everything?

 

[Ambitwistor]

Originally posted by Eepl
It has to create a force, a push if you will, that makes that chemical reaction.

Massless particles exert a force on other bodies, because they carry momentum, like everything else that exerts a force.

 

[Eepl]

K, a massless particle may exert a force. But because it's massless the particle can't move anything. For every amount of push forward it has to have an equal or opposite push back. One of Newton's laws. ex. An ant pushing a tank.
What I'm saying is that if it had no mass then there would be nothing to push against. The photon would just bounce off all matter, and nothing would happen.

 

[Ambitwistor]

Originally posted by Eepl
K, a massless particle may exert a force. But because it's massless the particle can't move anything.

Of course it can. If it exerts a force on something, then it can move it, just like any other application of force. Look up "light sails" and "radiometers" or "light-mills".

For every amount of push forward it has to have an equal or opposite push back.

So? That's true of massive particles too.

One of Newton's laws. ex. An ant pushing a tank.

Are you just saying that a photon exerts a small force? That's true. (So does, say, an electron.) Many photons can exert a larger force.

What I'm saying is that if it had no mass then there would be nothing to push against.

Huh? A photon pushes against whatever it runs into, just like anything else.

The photon would just bounce off all matter, and nothing would happen.

That's not true. A reflected photon will exert a force on the surface against which it reflects, just like a reflected electron. Or photons can be absorbed outright, also exerting a force.

 

[russ_watters]

Originally posted by Ambitwistor
No, but its path is determined by its speed, not its mass. (Galileo's observation. Of course, it is true that a massive particle can't travel at the same speed as a massless one.

I'm not sure what you mean by "a different gravitational interaction" here ...

... if you shoot two planets past a star at different speeds, the slower one will have its path bent more, but that's not because the force of gravity upon it is any stronger than on the other.

If the deflection is different because the speed is different, that's still a difference, right? And its speed is most certainly related to its mass: a particle with mass can't travel at the speed of light. Yes, two particles with mass will follow different trajectories if they are at different speeds, but neither will follow the trajectory of a massless particle.

So its still correct to say a particle with mass will behave differently here. It will follow a different path than a particle without mass - the fact that two particles with mass may also follow different paths is not the point. The point is neither will ever follow the same path as a particle without mass (unless maybe falling straight toward the massive object). Is this because of the mass or the speed? Is the speed related to the mass (mass certainly has a speed limit)? Chicken? Egg? Does it matter?


In any case, clearly I don't quite have the physics vocabulary to express this stuff quite right. I understand everything you are saying - sorry if I express it incorrectly.

 

[Eepl]

Here is as simple as I can put it.

Less Mass=Less Force. No Mass=No Force. 1=1, 0=0. If it has no mass it cannot move other mass.