@BrianK

Quote:

BrianK wrote: @Lou Quote: If light propagates thru space without slowing down, why would its momentum change with distance? Here's a simple experiment - turn on the light next to you and you clearly will observe the strength of light decreases by the ratio of 1/ distance squared. Think of the waves of your light emitting source. They are released at the same direction all at once. If we could take a static image, like a picture, the wave would form a sphere around the emitting source. The wave expands equidistantly in all directions. Sometime later we take a second static image. The second image's sphere is larger than the first images because the wave has expanded during it's travel. Initally we had force X from a point. As it grew into a sphere we then had the same force, X, over the area of a sphere (4*pi*radius*radius is the formula for area of the sphere). So if the 2nd sphere is twice the distance the force per surface area is reduced by 1/radius*radius or 1/2*2 or 1/4. So the inverse square law dictates how the power is reduced as the energy travels. But, if you really believe the inverse square law to be wrong then so is every single astronomical distance we've ever measured. As the inverse square law figures prominently on how we calculate distances.

See, you seem totally confused. At a distance x more where let's say you can look at the edges of the sun at a 45 degree up and down, left and right are hitting you than at a far distance where the sun is but a spec at 1 degree up and down and left and right. What weakens it is if some medium stands between you but the few rays that actually point at you aren't weaker, there are just fewer of them pointed at you at a farther distance.

Look at it this way, the speed of light in a vacuum is fixed. It's not called the "deceleration of light in a vacuum". I now see why you and das Nimrod make so many physics errors...

I mean don't you find it odd that gravity is directly related to area? Volume is cubic but gravity is really based on the perceived distance in area, not volume at a distance... Basically, you can say that a circular plate has a mass/density X and as the net area of that circle shrinks with distance, so does the gravitational effect ... which is exactly what the shadowing of radiation pressure says it does... You can see this clearly here: http://blazelabs.com/e-exp11.asp

Last edited by Lou on 28-May-2012 at 07:11 AM.

@Nimrod

Quote:

Nimrod wrote: @Lou Quote: Nimrod, show me where I equated 1 Joule to anything. I can't because you have never had either the intellectual integrity, or the mathematical ability to do anything other than make ridiculous unsupported assertions. What you have done in every single one of your baseless assertions is assume that because a force exists, it absolutely must be the dominant force because Lou says so. What I have tried to let you know is that I am aware of not only the existence of these forces, but also their magnitude. Quote: While your at it, since said asteroid is in orbit, what is the force of gravity on it from the sun? At any point in its orbit the gravitational attraction can be calculated using the rule of thumb formula devised by Newton. You do remember F=G((m1 x m2)/r^2) don't you? I am aware that Newton's law has since been superseded by Einstein's theory of general relativity, but it continues to be used as an excellent approximation of the effects of gravity. Relativity is required only when there is a need for extreme precision, or when dealing with gravitation for extremely massive and dense objects. Relativity was used to perform the calculations because the radiation pressure force they were measuring was so minuscule. On the subject of precision, and in response to an earlier question of yours "Where did I mention Nassim Haramein in my original post?" I do not require your permission to point out the differences in accuracy and precision between one of your heroes and real scientists, and Harameins "nearly right" is just another way of saying wrong.

so basically you refuse to answer my question...
Ok nimrod, stay the course...
You call one force weak but when asked to calculate the "other force" you have nothing to say but rhetoric...
You're also on your way to earning the BrianK award for putting words in my mouth.
GJ!

Last edited by Lou on 28-May-2012 at 06:55 AM.

@Lou

Quote:

See, you seem totally confused

That'd be you my friend.
Quote:

Look at it this way, the speed of light in a vacuum is fixed

No one, well except for you trying to twist an explaination, is stating it's not. It's the intensity of the effect that changes with distance per the inverse square law. That doesn't mean the speed changes. What I'm talking here is intensity. You claim to know lots about EM (though seem to never post any equations). So I'll just reference it for you - Lorentz Force. This is Force per unit Volume. The inensity decreased because
the volume increased.

Again - as EM is released in all directions from an object, eg our sun, the intensity of the force decreases as it travels. (I'll include it travels at c because you seem to be very confused about that.) The relationship for change in intensity here is related to the volume of a sphere. Or in short - the inverse square law - 1 / radius * radius.

And again why are we talking this? You claimed the reason galaxies cannot be effected by gravity is because they're too far apart. Conversely, you argued light (EM) does impact them. Your problem here is that then intensity of gravity and light change by exactly the same amount. This makes distance is unimportant to the question of the predominate force; as the ratio of forces always remains constant. The predominate force is determined at the point of emission. If the object emits more EM than gravity then EM will always dominate. If the object emits more gravity than EM (like our sun) then gravity will always dominate.

Last edited by BrianK on 28-May-2012 at 03:40 PM.

@BrianK

Quote:

BrianK wrote: @Lou Quote: See, you seem totally confused That'd be you my friend. Quote: Look at it this way, the speed of light in a vacuum is fixed No one, well except for you trying to twist an explaination, is stating it's not. It's the intensity of the effect that changes with distance per the inverse square law. That doesn't mean the speed changes. What I'm talking here is intensity. You claim to know lots about EM (though seem to never post any equations). So I'll just reference it for you - Lorentz Force. This is Force per unit Volume. The inensity decreased because the volume increased. Again - as EM is released in all directions from an object, eg our sun, the intensity of the force decreases as it travels. (I'll include it travels at c because you seem to be very confused about that.) The relationship for change in intensity here is related to the volume of a sphere. Or in short - the inverse square law - 1 / radius * radius. And again why are we talking this? You claimed the reason galaxies cannot be effected by gravity is because they're too far apart. Conversely, you argued light (EM) does impact them. Your problem here is that then intensity of gravity and light change by exactly the same amount. This makes distance is unimportant to the question of the predominate force; as the ratio of forces always remains constant. The predominate force is determined at the point of emission. If the object emits more EM than gravity then EM will always dominate. If the object emits more gravity than EM (like our sun) then gravity will always dominate.

No, "we" are/were not talking about Lorentz force. "We" are talking about the inertia of LIGHT. I'll correct you now: http://www.youtube.com/watch?v=FAivtXJOsiI
So did you see how light had the same energy before it passed thru water as after?
Sometimes you are so smart that your stupid, a figure of speech.
Light changes frequency when its absorbed and then emitted at a different frequency...which makes it a different "light" wave or particle altogether.

So a photon's speed and energy is constant until it hits something.

Last edited by Lou on 28-May-2012 at 09:46 PM.

@Lou

Who are you arguing with exactly? What you just wrote can easily be summed up by "you are an idiot and I agree with you".

A photon cannot change or be changed, it can only be absorbed or emitted. So when the momentum of light changes, that means the photon COUNT has changed. Changing the photon COUNT doesn't change the velocity, which answers your earlier question of how speed can be fixed and momentum can be changing.

_________________
This weeks pet peeve:
Using "voltage" instead of "potential", which leads to inventing new words like "amperage" instead of "current" (I, measured in A) or possible "charge" (amperehours, Ah or Coulomb, C). Sometimes I don't even know what people mean.

@Lou

Quote:

"We" are talking about the inertia of LIGHT

We are not talking about the inertia of light. We are talking about the force light has on an object. I'll requote you so you can see that.
Quote:

What this alludes to is why galaxies that are too far apart to significantly be affected by the "gravity" can still push themselves apart by throwing light at each other as I tried to explain to you 10's of pages ago when I first introduced the conecept of radiation pressure as an explanation for gravity...

Light is emitted from an object in photons. Those photons do indeed travel at the same speed unless interfered with. However, the photons spread out in a sphere from the originating object. The intensity of the force is what moves the object. Intensity of light could be seen as photons per volume. For example, when you have the same number of photons but a larger volume the intensity of force is weaker. By how much? Well by the change in the volume of the sphere they occupy. Mathematically this is defined by the inverse square law.

So you can do an experiment to verifry the 'force of light' on your eye. When you are close to the light bulb the light is more intense. Because more photons are hitting your eyeball. When you are farther away the light is dimmer because less photons are hitting your eyeball.

Force on an object is dependent not only on inertia but number of photons overall hitting that object. And we can handle gravity in the same fashion. It's a force with the same inertia (speed of light) that is decreased the further you get from the object by the inverse square law.

So now we have two competiting forces. The Force of Gravity and the Force of Light. Which one effects the objects more is dictated by the intensity of the Forces we're comparing. When the force of gravity is greater than the force of light (or vice versa) that relationship remains in effect because both insensities are changed by the same amount, the inverse square law.

Quote:

So a photon's speed and energy is constant until it hits something.

We agree. Though a single photon is far short of the big picture here! Which is likely why you're claims of EM are off ordinal amounts from that is truly in play.

@Lou

Quote:

"We" are talking about the inertia of LIGHT. I'll correct you now: http://www.youtube.com/watch?v=FAivtXJOsiI So did you see how light had the same energy before it passed thru water as after?

Thank you for that link Lou, it has got to be the best, and most comprehensible metaphor for something that some people seem to find hard to understand. And no, I am not being sarcastic.

The problem is that most light sources do not release light one photon at a time , and except in the case of a laser, the photons do not all go in the same direction, they radiate in all directions equally. Although each individual photon has the same energy, as the range from the source increases, so the same energy is spread across a greater area of the sphere around the source. This is why stars a hundred light years away are dimmer, and exert less gravitational effect on us than our own Sun does.

_________________
When in trouble, fear or doubt, run in circles, scream and shout.

@olegil

Quote:

olegil wrote: @Lou Who are you arguing with exactly? What you just wrote can easily be summed up by "you are an idiot and I agree with you".

I think that is easily answered by what ever comes after the @ in the first line of any message...

Quote:

A photon cannot change or be changed, it can only be absorbed or emitted. So when the momentum of light changes, that means the photon COUNT has changed. Changing the photon COUNT doesn't change the velocity, which answers your earlier question of how speed can be fixed and momentum can be changing.

You are an idiot and I agree with you and that's one of the things I was trying to tell BrianK when he says its freqency changes with distance... I was never asking a question... Perhaps you should pay more attention to BrianK's mistakes, eh?

Last edited by Lou on 29-May-2012 at 08:23 PM.

@BrianK

Quote:

BrianK wrote: @Lou Quote: "We" are talking about the inertia of LIGHT We are not talking about the inertia of light. We are talking about the force light has on an object. I'll requote you so you can see that. Quote: What this alludes to is why galaxies that are too far apart to significantly be affected by the "gravity" can still push themselves apart by throwing light at each other as I tried to explain to you 10's of pages ago when I first introduced the conecept of radiation pressure as an explanation for gravity... Light is emitted from an object in photons. Those photons do indeed travel at the same speed unless interfered with. However, the photons spread out in a sphere from the originating object. The intensity of the force is what moves the object. Intensity of light could be seen as photons per volume. For example, when you have the same number of photons but a larger volume the intensity of force is weaker. By how much? Well by the change in the volume of the sphere they occupy. Mathematically this is defined by the inverse square law. So you can do an experiment to verifry the 'force of light' on your eye. When you are close to the light bulb the light is more intense. Because more photons are hitting your eyeball. When you are farther away the light is dimmer because less photons are hitting your eyeball. Force on an object is dependent not only on inertia but number of photons overall hitting that object. And we can handle gravity in the same fashion. It's a force with the same inertia (speed of light) that is decreased the further you get from the object by the inverse square law. So now we have two competiting forces. The Force of Gravity and the Force of Light. Which one effects the objects more is dictated by the intensity of the Forces we're comparing. When the force of gravity is greater than the force of light (or vice versa) that relationship remains in effect because both insensities are changed by the same amount, the inverse square law. Quote: So a photon's speed and energy is constant until it hits something. We agree. Though a single photon is far short of the big picture here! Which is likely why you're claims of EM are off ordinal amounts from that is truly in play.

BrianK, it is a proven fact that light has inertia/momentum. As usual you twist the original issue. Solar sails are science fact. They aren't magical, just a big thin sheet of metal for light to bounce off of.

As for the light bulb, its more intense because a higher concentration of photons is interacting with air heating up the air closer to the bulb. So you have more dispersion with distance. Space is considered a vacuum and I was specifically talking about the vacuum space between galaxies...

You also continue to complicate this. I gave you specific criteria: galaxies too far apart to be significantly affected by each other's gravitational effect. What exactly does my eye and a light bulb have to do with that?

Your microscopic example is useless.

@Nimrod

Quote:

Nimrod wrote: @Lou Quote: "We" are talking about the inertia of LIGHT. I'll correct you now: http://www.youtube.com/watch?v=FAivtXJOsiI So did you see how light had the same energy before it passed thru water as after? Thank you for that link Lou, it has got to be the best, and most comprehensible metaphor for something that some people seem to find hard to understand. And no, I am not being sarcastic. The problem is that most light sources do not release light one photon at a time , and except in the case of a laser, the photons do not all go in the same direction, they radiate in all directions equally. Although each individual photon has the same energy, as the range from the source increases, so the same energy is spread across a greater area of the sphere around the source. This is why stars a hundred light years away are dimmer, and exert less gravitational effect on us than our own Sun does.

So what I'm trying to say is let's say you had 2 objects, the sun and a "planet" the same exact size as the sun. Lets simplify that the photons saying they only radiate directly at each body matching point for opposing point. At any given distance, that means the # of photons pointing at the planet is always equal to how many can fit in the cross-section of the sun[ or planet]. This will never change with distance. So you see, while the gravitational effect can dwindle down to nothing, the solar pressure can remain fixed as long as the sun continues to emit light...

@Lou

Quote:

BrianK, it is a proven fact that light has inertia/momentum

Great point. Though not sure why you're repeating an agreed upon component of the discussed.

Quote:

As for the light bulb, its more intense because a higher concentration of photons is interacting with air heating up the air closer to the bulb. So you have more dispersion with distance. Space is considered a vacuum and I was specifically talking about the vacuum space between galaxies...

Yes certainly light playing off of air will effect larger than the inverse square law that is in play in the vacuum of space. So not a perfect experiment. Though sufficent for you to understand you don't get the same light close to and far away from the emitting object.

Within the vaccum an unimpeded light source will have it's intensity reduced by the inverse square law. The amount of energy hitting Venus doesn't hit Earth. We receive a less intensity from the sun than does Venus. Take the light meter you just used in your room and fly to the same distance Venus is from the sun. Take a reading. Fly to the same distance Earth is from the sun, take a reading. What you'll find is Earth's reading is less than Venus's reading. And you'll find these numbers differ by the inverse square rule.

Quote:

I gave you specific criteria: galaxies too far apart to be significantly affected by each other's gravitational effect.

And do note I did use your condition. Gravity, traveling at the speed of light, has it's intensity reduced per the inverse square law. Light, traveling at the speed of light, has it's intensity reduced per the inverse square law. If the inital condition (like our sun) is such that the forces of gravity is greater than the forces of EM and nothing interferes with either force the ratio between the two will remain constant. (NOTE: nothing interfering with either force is a special condition of your specific criteria that nothing interferes with EM. I'm treating both forces equally unoppsed in their Journey. Though reality often differs from your special case and it's extension.)

Last edited by BrianK on 29-May-2012 at 09:18 PM.

Here's something you don't hear every 40,000 years...
http://arstechnica.com/science/2012/05/rock-of-ages-40000-year-old-musical-instruments-the-worlds-oldest/

@BrianK

Quote:

BrianK wrote: @Lou Quote: BrianK, it is a proven fact that light has inertia/momentum Great point. Though not sure why you're repeating an agreed upon component of the discussed. Quote: As for the light bulb, its more intense because a higher concentration of photons is interacting with air heating up the air closer to the bulb. So you have more dispersion with distance. Space is considered a vacuum and I was specifically talking about the vacuum space between galaxies... Yes certainly light playing off of air will effect larger than the inverse square law that is in play in the vacuum of space. So not a perfect experiment. Though sufficent for you to understand you don't get the same light close to and far away from the emitting object. Within the vaccum an unimpeded light source will have it's intensity reduced by the inverse square law. The amount of energy hitting Venus doesn't hit Earth. We receive a less intensity from the sun than does Venus. Take the light meter you just used in your room and fly to the same distance Venus is from the sun. Take a reading. Fly to the same distance Earth is from the sun, take a reading. What you'll find is Earth's reading is less than Venus's reading. And you'll find these numbers differ by the inverse square rule. Quote: I gave you specific criteria: galaxies too far apart to be significantly affected by each other's gravitational effect. And do note I did use your condition. Gravity, traveling at the speed of light, has it's intensity reduced per the inverse square law. Light, traveling at the speed of light, has it's intensity reduced per the inverse square law. If the inital condition (like our sun) is such that the forces of gravity is greater than the forces of EM and nothing interferes with either force the ratio between the two will remain constant. (NOTE: nothing interfering with either force is a special condition of your specific criteria that nothing interferes with EM. I'm treating both forces equally unoppsed in their Journey. Though reality often differs from your special case and it's extension.)

Your example is flawed.
Gravity will approach zero...light can travel forever. If by "it's intensity", you mean the # of photons, that doesn't matter because that # will always be atleast how many you can cram into a cross-section of the body in question that is being pushed. Now in the case of galaxies, they both emit light, so the force is now doubly so...

See my response to Nimrod...

@Lou

Quote:

Lets simplify that the photons saying they only radiate directly at each body matching point for opposing point. At any given distance, that means the # of photons pointing at the planet is always equal to how many can fit in the cross-section of the sun[ or planet]. This will never change with distance

Your simplification is not an accurate representation of how light radiates from a point source. A steady light source radiates the same number of photons each and every second. The light radiating from a point source after one second fills the surface of a sphere one light second in diameter. One second later that same amount of energy is distributed around the surface of a sphere two light seconds in diameter, and an object with a fixed surface area will recieve one quarter of the radiant energy at this distance. The same object at a distance of three light seconds will recieve only one ninth the radiant energy. It is for this reason that Neptune owes its blue colouration to its oceans of liquid methane, not water, as despite having a surface area sixteen times that of the Earth it is thirty times as far, and recieves 0.1% of the amount of heat and light per square metre, or 1.7% of the total heat compared to our own planet. This link will show the point better than I can, and it includes a simple diagram so it should be easier to follow. When a rocket lifts off it is not a result of the bright light shining at the bottom end thrusting it up, but a result of the expulsion of mass from the rocket. If it were any different, these would never get off the ground.

_________________
When in trouble, fear or doubt, run in circles, scream and shout.

@Nimrod

Quote:

Nimrod wrote: @Lou Quote: Lets simplify that the photons saying they only radiate directly at each body matching point for opposing point. At any given distance, that means the # of photons pointing at the planet is always equal to how many can fit in the cross-section of the sun[ or planet]. This will never change with distance Your simplification is not an accurate representation of how light radiates from a point source. A steady light source radiates the same number of photons each and every second. The light radiating from a point source after one second fills the surface of a sphere one light second in diameter. One second later that same amount of energy is distributed around the surface of a sphere two light seconds in diameter, and an object with a fixed surface area will recieve one quarter of the radiant energy at this distance. The same object at a distance of three light seconds will recieve only one ninth the radiant energy. It is for this reason that Neptune owes its blue colouration to its oceans of liquid methane, not water, as despite having a surface area sixteen times that of the Earth it is thirty times as far, and recieves 0.1% of the amount of heat and light per square metre, or 1.7% of the total heat compared to our own planet. This link will show the point better than I can, and it includes a simple diagram so it should be easier to follow. When a rocket lifts off it is not a result of the bright light shining at the bottom end thrusting it up, but a result of the expulsion of mass from the rocket. If it were any different, these would never get off the ground.

I intentionally simplified my example to show the minimum about of photons that will hit an equal sized body at any given distance. I made the sun a laser fired at a "planet" of equal diameter. What you are talking about is all points on the sun emitting many more photons in all directions. Your wave that loses intensity is just a loss in idividual photons that are not directly aimed at and hitting a viewing source and the graphic in your first link shows you this. So while gravity can approach 0 force, EM pressure cannot fall below a threshold unless the source disappears...

For instance at a distance of infinity, the amount of photons packed into the cross-section of the sun could still be hitting my equally-sized planet. What would gravity be? 0

Last edited by Lou on 30-May-2012 at 12:09 AM.

@Lou

Quote:

Lets simplify that the photons saying they only radiate directly at each body matching point for opposing point.

The problem with this simplification is it greatly breaks the representation of reality. The sun does not shoot light out like a laser as you describe. The sun radiates the EM field in all directions. If we measure the EM energy just outside of each planet we find the EM drops off.

I know this concept is hard for you to undertake but a postulate must be supported with evidence to understand how well it fits with reality. When we measure the EM from the sun outside of Venuswe find it is larger than the EM outside of earth. Both planets are in alignment in the manner you describe. And the earth is farther and larger. If distance didn't matter, as you want to claim, Earth should receive more energy than Venus. In reality Venus receives more.

I had previously only scratched the surface of how out of alignment it was. Your recent detail makes it fairly clear your simplification makes your model broken from the outset.

Quote:

If by "it's intensity", you mean the # of photons, that doesn't matter because that # will always be atleast how many you can cram into a cross-section of tFor instance at a distance of infinity, the amount of photons packed into the cross-section of the sun could still be hitting my equally-sized planet the body in question that is being pushed

With your simplification that would be true. When compared again with EVIDENCE this claim is not true either.

As demonstrated by EVIDENCE not supposed by imaginary laser stars: gravity and light both have the properties of inertia at the speed of light and intensity reduced by the inverse square law. If both forces travel unimpeded the ratio between the forces will remain a constant. The dominate force from the emitting object will always remain dominant.

I will agree that is contrived as it assumes no other gravitational or EM forces come into play. Though it is a step closer match to reality and that's what we're trying to understand afterall.

Last edited by BrianK on 30-May-2012 at 03:36 AM.

@BrianK

Reading the last two pages have just been baffling. He just does not accept that light is spread out in three dimensions.

_________________
This weeks pet peeve:
Using "voltage" instead of "potential", which leads to inventing new words like "amperage" instead of "current" (I, measured in A) or possible "charge" (amperehours, Ah or Coulomb, C). Sometimes I don't even know what people mean.

@olegil

Quote:

Reading the last two pages have just been baffling. He just does not accept that light is spread out in three dimensions.

Yeah kinda. Lou indeed makes his own model. One where light is artifically constrained, aka like a laser he says, and is emitted into an unconstrained universe. What he says is certainly true in reference to the model.

The problem I see here is fairly simple. Lou's model of the universe is nothing like the universe. Lou's model constrains EM from the Sun. In reality Suns don't emit light like a laser. Lou's model is an unconstrained universe. In reality the universe is constrained as other objects are always emitting their own forces of gravity and EM. These cause collinsons and interference. Again what we see is Lou asserted a model, claimed it true, and skipped over the reviewal of evidence. It's been a consistent problem and one that makes Lou's claim of truth unverifiable. The result isn't just bad science it's worse. It's non-scientific because the constructs are unfalsiable.

@olegil

Quote:

olegil wrote: @BrianK Reading the last two pages have just been baffling. He just does not accept that light is spread out in three dimensions.

What's baffling is how you mis-interpret everything I post.

I do realize it, but according to the definition of light, it's quantasized into photons. Spreading out in "all directions" = lots of photons.

I am only concerning myself with photons in 1 direction to make a point.

What's baffling is that you don't understand the point.

@BrianK

Quote:

BrianK wrote: @Lou Quote: Lets simplify that the photons saying they only radiate directly at each body matching point for opposing point. The problem with this simplification is it greatly breaks the representation of reality. The sun does not shoot light out like a laser as you describe. The sun radiates the EM field in all directions. If we measure the EM energy just outside of each planet we find the EM drops off. I know this concept is hard for you to undertake but a postulate must be supported with evidence to understand how well it fits with reality. When we measure the EM from the sun outside of Venuswe find it is larger than the EM outside of earth. Both planets are in alignment in the manner you describe. And the earth is farther and larger. If distance didn't matter, as you want to claim, Earth should receive more energy than Venus. In reality Venus receives more. I had previously only scratched the surface of how out of alignment it was. Your recent detail makes it fairly clear your simplification makes your model broken from the outset. Quote: If by "it's intensity", you mean the # of photons, that doesn't matter because that # will always be atleast how many you can cram into a cross-section of tFor instance at a distance of infinity, the amount of photons packed into the cross-section of the sun could still be hitting my equally-sized planet the body in question that is being pushed With your simplification that would be true. When compared again with EVIDENCE this claim is not true either. As demonstrated by EVIDENCE not supposed by imaginary laser stars: gravity and light both have the properties of inertia at the speed of light and intensity reduced by the inverse square law. If both forces travel unimpeded the ratio between the forces will remain a constant. The dominate force from the emitting object will always remain dominant. I will agree that is contrived as it assumes no other gravitational or EM forces come into play. Though it is a step closer match to reality and that's what we're trying to understand afterall.

Read http://en.wikipedia.org/wiki/Photon
A photon has no electrical charge but has inertia. Why do you keep telling me that it's EM force diminished with distance?

There is also this:
http://en.wikipedia.org/wiki/Radiation_pressure
Quantum Theory Argument
From the perspective of quantum theory, light is made of photons: particles with zero mass but which carry energy and —importantly in this argument— momentum . According to special relativity, because photons are massless their energy (E) and momentum (p) are related by E=pc [3].

Now consider a beam of light perpendicularly incident on a surface, and let us assume the beam of light is totally absorbed. If we imagine the beam is made of photons, then every second numerous photons strike the surface and are absorbed. The momentum the photons carry is a conserved quantity—that is, it cannot be destroyed—so it must be transferred to the surface; the result is that absorbing the light beam causes the surface to gain momentum.

Newton's Second Law tells us that force equals rate of change of momentum, so during each second the surface experiences a force (or pressure, as pressure is force per unit area) due to the momentum the photons transfer to it. We have:

Pressure = momentum transferred per second per unit area = Energy deposited per second per unit area / c = I/c.

Where I is the intensity of the beam of light (measured in e.g. W⋅m-2).

In the above argument we assumed that the surface totally absorbed the beam, in general light can be transmitted, reflected and/or absorbed. If the light were totally reflected then the radiation pressure is doubled compared to total absorption, this is because the photons arrive with momentum E/c and depart with momentum -E/c (the -ve sign indicates traveling in the opposite direction), so the change of momentum is 2E/c.

Can you explain to me where DISTANCE is in the radiation pressure equation?

Last edited by Lou on 30-May-2012 at 05:15 PM.
Last edited by Lou on 30-May-2012 at 05:10 PM.