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originally posted by: mbkennel



Photons do not interact with one another, meaning that the electromagnetic field dynamics is linear.

Regarding your example, you're talking about matter interacting with the EM field which then interacts with other charged matter. Photons (in free space) do not mutually interact directly.

In a vacuum;

[S======N] (Real quantity of space---repulsion) [N=======S]


0 = Photon

[S=====N] (oooooooooooooooooo) [N=======S]


Unless you are trying to argue regardless of the distance between the two repulsing magnets;

there is only ever 1 singular photon between them physically responsible for keeping them a distance apart.


[S=======N] (o) *1 [N=======S]

[S=======N] (o) *2 [N=======S]

[S=======N] (o) *3 [N=======S]


*1 = 1 mm

*2 = 1 cm

*3 = 1 in

Instead of

[S=======N] (oooo) *1 [N=======S]

[S=======N] (oooooooooooo) *2 [N=======S]

[S=======N] (ooooooooooooooooooooo) *3 [N=======S]



Oh, though I understand what you might mean;

[S========N] o------>


o-------> [N=======S]

a reply to: ImaFungi

Photons don't have magnetic poles or electric charge. So there's no "N-S" sort of thing associated with them.

They DO have E and H fields. But they are not themselves magnetic or electric in the way you depict.

eta: If you're talking about HOW magnets repel each other, you also can't imagine a single photon hovering in space between the two like a yellow wooden ball. First, photons don't hang around. Second, it's virtual photons, not instantiated ones.

Ok 3 main questions that I am still trying to understand.

#1. If pi=3.14....................... by its definition, is it useful for anything outside of 2 dimensional drawings, or two dimensional thought. Because the application of PI in the moving universe get's a more correct answer to problems with PI also taking into account movement. Many engineers have concluded that applicable PI = 4!

#2. I am still unsure, (accepting that multiple dimensions are real) if we live in the third or fourth dimension. up, down, left, right, and forward with time. If time is a constant between dimensions, or is it a byproduct of our dimension. If it is a byproduct, then a sentient being in the next higher dimension could pick out any specific point of our time and view it. Thus time is irrelevant, they could move forward and back from our relation to them. However how could a sentient being exist without a forward movement of time?

#3. Now this one I know has an answer, but no one I ask can give it to me. Lets start with Helium. To my understanding helium is just two fused hydrogen atoms. We can pull them apart and get two hydrogens. Well when we pull 1 hydrogen apart, what and where do it's parts go? I know this is a simplistic view of how a Hbomb does its magic, but I want to know does it just fall apart forever into tiny quarks, or does it come back together to form something? I mean there are charged particles that have to go somewhere.

Thanks in advance!

1) citation required, iv never heard of any engineer conclude that Pi = 4, Pi has many applications, while the definition is defined by the 2d treatment of circles, it is a quantity that pops up in many places and in 3d

there is nothing magical about moving to extra dimensions or any reason why it should go to 4... so yes citation needed. The question in the middle also makes little sense, please rephrase it

2) We exist in 3 physical spacial dimensions and time as the 4th moves everything along. it is unknown currently what consciousness is, and how sentience arrises. There are a lot of ifs to this question and it then becomes highly speculative and less and less scientific. I suspect sentience requires information transfer and chemical processes to work, these require time.

3) Well, firstly that is not how a HBomb works. You do not split helium to form two hydrogen in such a device, so the question is flawed.

However if you are to pull a hydrogen apart. firstly the terminology is incorrect. You cannot pull one apart, you have to smash it apart. And what occurs when this is done is known as hadronisation. When a quark is moved away from its neightbours in a proton, the process quantum chromodynamics defines that colour charge must be consereved. Thus a gluon from the proton converts into a quark-anti quark pair. One remains in the proton, the other pairs with the one removed to form a meson. At higher energies you get more exotic processes occurring also.

In nature it appears impossible to isolate a lone quark... it has never been achieved despite all the effort to do so

In experiments verifying the Bell Inequality, after the first entangled particle is measured, the second shows a correlation via a change in the observed probabilities of certain of its quantum states. But who is to determine which measurement went first in certain relitavistic frames? Does this experiment require a "right now", determining which measurement went first even though in the general theory of relativity, it is ambiguous (under the right conditions) which event occurs "first".

Say you are in a space ship traveling 3/4 the speed of light. Another spaceship going the other direction at 3/4 the speed of light. Technically wouldn't you then be traveling 1.5 the speed of light relative to that other spaceship? Would your mass approach infinity? Would you go back in time? Heaven forbid you turn on your headlights and they go backwards.

a reply to: ErosA433
Great answer, thanks. I don't get all the garbage I've seen about Pi on the internet, but I can only surmise those propagating it aren't engineers or scientists since I think it seems fairly straightforward to those groups.

originally posted by: tombaccei
In experiments verifying the Bell Inequality, after the first entangled particle is measured, the second shows a correlation via a change in the observed probabilities of certain of its quantum states. But who is to determine which measurement went first in certain relitavistic frames? Does this experiment require a "right now", determining which measurement went first even though in the general theory of relativity, it is ambiguous (under the right conditions) which event occurs "first".

"now" is only ambiguous if you have different observers in different frames of reference. For single non-accelerating reference frame, now isn't ambiguous.

If the experiment is done on Earth you can use Earth for your reference frame in which case "now" becomes less ambiguous. Using this reference frame it was established that the speed of entanglement is at least 10,000 times faster than the speed of light but apparently that was the limit of measurement accuracy since the experiment didn't rule out faster speeds.

originally posted by: AshFan
Say you are in a space ship traveling 3/4 the speed of light. Another spaceship going the other direction at 3/4 the speed of light. Technically wouldn't you then be traveling 1.5 the speed of light relative to that other spaceship?

A similar question was asked and answered on page 306. In this link the math is shown for 2 objects traveling at 99% the speed of light, just replace the .99 with .75 for your variant of the question:

www.abovetopsecret.com...

So the speed of light really is a speed limit in local cases. In non-local cases, it's not, for example the most distant galaxies are receding from us at over two times the speed of light.

Would your mass approach infinity?

Mass would not increase at all (despite some incorrect textbook claims to the contrary), just momentum and energy.

Explained more here on page 311:

www.abovetopsecret.com...

Would you go back in time?

No.

Two similar, if opposite questions from me

Can light (photons) erode things? -and-
Since Heat radiation is photons in the IR wavelength, if you maintain an objects temperature above 0 kelvin, will that object lose mass over time from photon emission?

originally posted by: MasterAtArms
Two similar, if opposite questions from me

Can light (photons) erode things?

Like this laser rust remover?

Since Heat radiation is photons in the IR wavelength, if you maintain an objects temperature above 0 kelvin, will that object lose mass over time from photon emission?

The question is a little contradictory, since if you "maintain the temperature" that implies it's not going down so it won't lose energy. The background temperature of the universe (CMB) is 2.725 K so an object at that temperature isn't going to cool down or lose energy without intervention, since the CMB will tend to keep it from getting colder than that.

If you take a hot mass like your frying pan and and let it cool after taking it off the stove, then it loses kinetic energy but since it's not losing momentum then you have to say it's losing mass, so in this case scale matters whether you're talking about a large object or an individual particle. If you cool off particles in a hot interstellar gas cloud, I would say an individual particle has lost kinetic energy and momentum, rather than mass.

originally posted by: Arbitrageur

originally posted by: MasterAtArms
Two similar, if opposite questions from me

Can light (photons) erode things?

Like this laser rust remover?

Since Heat radiation is photons in the IR wavelength, if you maintain an objects temperature above 0 kelvin, will that object lose mass over time from photon emission?

The question is a little contradictory, since if you "maintain the temperature" that implies it's not going down so it won't lose energy. The background temperature of the universe (CMB) is 2.725 K so an object at that temperature isn't going to cool down or lose energy without intervention, since the CMB will tend to keep it from getting colder than that.

If you take a hot mass like your frying pan and and let it cool after taking it off the stove, then it loses kinetic energy but since it's not losing momentum then you have to say it's losing mass, so in this case scale matters whether you're talking about a large object or an individual particle. If you cool off particles in a hot interstellar gas cloud, I would say an individual particle has lost kinetic energy and momentum, rather than mass.

Maybe my first question was a little unclear, but thanks for the answer to the second.

What I meant about light erosion - I'm not talking about super high power lasers and such, but is there still an effect at extremely low levels?

Say you fire a single photon every second for a trillion years at some inert object. Will that still have a cumulative "eroding" effect on that mass in a completely sealed and closed system?

originally posted by: MasterAtArms
What I meant about light erosion - I'm not talking about super high power lasers and such, but is there still an effect at extremely low levels?

Say you fire a single photon every second for a trillion years at some inert object. Will that still have a cumulative "eroding" effect on that mass in a completely sealed and closed system?

I think "extremely low levels" needs to be defined to answer the question. I think the key factor for whether erosion occurs at all wouldn't be so much the number of photons (though that could affect erosion rate), but the energy level of the photons. If the photons are radio waves that don't interact with the material significantly then I'm not sure what mechanism could cause erosion. But as the photons have higher and higher energy, there are more mechanisms for them to interact, which might lead to erosion. I think you also need to consider the properties of the material being exposed to the photons with respect to how it reacts to them.

I've been involved in testing different materials exposed to ultraviolet light (the most damaging part of sunlight because it tends to be the highest energy part of the solar spectrum in any significant quantity) and some materials hold up a lot better than others. So for example you might find an expensive can of paint with a 20 year warranty is a better bargain than a cheap can of paint with a 5 year warranty since the longer lasting paint doesn't need to be applied as often and reduces the labor cost of applying new paint. The more expensive paint often has more expensive additives that stabilize it against UV degradation.

Glass on the other hand might not show any erosion or deterioration from the same UV exposure as the paint.

So it depends on the material and the energy level of the photons.

a reply to: Arbitrageur

Thanks for the great answer

a reply to: MasterAtArms
Thanks for the feedback, I'm glad you found the answer helpful.

a reply to: Arbitrageur

Loop quantum gravity can predict the entropy of black holes.

I learned that on The big bang theory.

a reply to: Arbitrageur

This is a great answer and i can likewise say that paint is a great example as UV tends to cause interaction or breakdown of chemicals, or promotion of chemical reactions.

Another great one that you can probably see on a day to day basis is in acrylic. Acrylic discolours under lots of UV light, unless it has an additive in order to absorb the UV in a manner that doesn't cause breakdown of bonds. So acrylic that has been exposed to UV photons for years tends to be slightly yellow and brittle compared to a virgin piece of acrylic.

You tent to see this more 'sorry' looking material used in bus stops or rain shelters.

In terms of erosion, physical chunks being removed, it is a very long process with light and other chemical and mechanical processes will always occur more rapidly. Which will remove chunks of a material faster... a mechanical and chemical effect... or photons... the answer 99.9999% of the time is... mechanical and chemical

originally posted by: ErosA433
In terms of erosion, physical chunks being removed, it is a very long process with light and other chemical and mechanical processes will always occur more rapidly. Which will remove chunks of a material faster... a mechanical and chemical effect... or photons... the answer 99.9999% of the time is... mechanical and chemical

No doubt under normal circumstances on Earth, erosion by photons is a very slow process greatly overwhelmed by the other processes you mention, but when I read MasterAtArms question initially, I thought more of lasers burning holes through metal, which isn't a natural process obviously. One special case that could be considered, is the tail of a comet a form of "erosion"? Maybe it depends on how erosion is defined. The volatile materials are being vaporized by solar radiation and they tend to carry dust along with them which I suppose could be considered a form of erosion.

The Earth has its erosion processes and the moon lacks some of those but it has others, like micrometeorites "sandblasting" the surface which I suspect would also would be far greater than the effects of photons in most cases. However an interesting unique subject that was discussed in the space forum here was the fact that apparently three Apollo flags on the moon can still be seen casting shadows and considering the fragile nature of the flags and the harsh environment on the moon some people seem a bit surprised they haven't eroded away or disintegrated.

www.hq.nasa.gov...

Intuitively, experts mostly think it highly unlikely the Apollo flags (See Platoff's article Where No Flag Has Gone Before: Political and Technical Aspects of Placing a Flag on the Moon for details), could have endured the 42 years of exposure to vacuum, about 500 temperature swings from 242 F during the day to -280 F during the night, micrometeorites, radiation and ultraviolet light, some thinking the flags have all but disintegrated under such an assault of the environment...

Combined with knowledge of the Apollo site maps which show where the flag was erected relative to the Lander, long shadows cast by the flags at three sites - Apollo 12, Apollo 16, and Apollo 17 - show that the these flags are still “flying”, held aloft by the poles.

I can see why some people are surprised those three flags haven't vanished like the others, especially since they were nothing special according to the manufacturer:

Over the years, the nylon would have turned brittle and disintegrated. … Dennis Lacarrubba, whose New Jersey-based company, Annin, made the flag and sold it to NASA for $5.50 in 1969, considers what might happen to an ordinary nylon flag left outside for 39 years on Earth, let alone on the moon. He thinks for a few seconds. “I can’t believe there would be anything left,” he concludes. “I gotta be honest with you. It’s gonna be ashes.

I've seen what UV tests in labs do to nylon and it's not pretty, it completely loses its structural integrity, but the analogy I thought of for how the flags might still be casting shadows are lantern mantles...they are literally ashes but they would be capable of casting shadows.

Pi=4 also known as Manhattan Metric, used by many engineers in the rocketry field. Outside of 2 dimensional thought process, I haven't found a single use where pi=3.14........ to have any practical use in application. Thus why I was asking if I am overlooking something. (to note: by practical use, I mean in actual product development outside of being used to measure static volume.)



the second question i got carried away by my entire thought experiment. Just wanted to know what the thoughts are on time being in account to dimensions. Does it theoretically happen in all dimensions, or is it just one part of a specific dimension?



Third question was answered perfectly!

a reply to: mcsjr454
Rounding up rather than down?

Can find no such thing as "Manhattan Metric" being used in rocketry.

a reply to: Arbitrageur


I see where you are going with this, so maybe I should expand on the question a bit


Does a high energy photon have enough energy to break a bond between atoms and "blow off" an atom (physical erosion) or is it rather those photons are causing a slight temperature increate in the material that causes the atoms to vibrate more (heat up) which causes the erosion process through other means? (vaporisation, sublimation etc)

originally posted by: MasterAtArms

Does a high energy photon have enough energy to break a bond between atoms and "blow off" an atom...

Depends on both photon and material, probably with other things as well like incident angle.

If you have a high enough photon energy, you can cause an atom to fission, if you've got the right material.

But you normally get thermal ablation.