Eren

How photons move?

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Itoero    41
On ‎29‎-‎9‎-‎2017 at 9:42 PM, Eren said:

My thought is that if there were pure wave they should be energy, and i dont think energy can move my itself without any matter.

All the energy of a photon is kinetic energy.https://en.wikipedia.org/wiki/Kinetic_energy

Edited by Itoero

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Itoero    41
3 hours ago, Strange said:

From that link: "It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity" which wouldn't seem to apply to light.

 

It depends how you interpret it. For photons I would change this definition a bit: 'Kinetic energy is defined as the work needed to accelerate a body without mass from rest to its stated velocity.'

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Strange    2543
27 minutes ago, Itoero said:

It depends how you interpret it. For photons I would change this definition a bit: 'Kinetic energy is defined as the work needed to accelerate a body without mass from rest to its stated velocity.'

As you can't accelerate a photon, that still doesn't seem to apply.

I suppose you could go a step further to define kinetic energy as: "the intrinsic energy of a massless particle". But then you are back to your habit of redefining words to match your opinions.

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Itoero    41
17 hours ago, Strange said:

As you can't accelerate a photon, that still doesn't seem to apply.

I suppose you could go a step further to define kinetic energy as: "the intrinsic energy of a massless particle".

That's true, but you can interpret a photon as being an accelerated packet of energy.

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Strange    2543
3 minutes ago, Itoero said:

That's true, but you can interpret a photon as being an accelerated packet of energy.

Can you? Please provide a reference for this.

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Itoero    41
19 minutes ago, Strange said:

Can you? Please provide a reference for this.

Seriously?

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Strange    2543
Just now, Itoero said:

Seriously?

Seriously.

Photons cannot be accelerated and "packet of energy" is a pretty poor pop-sci description. But it is in line with you just making stuff up as usual.

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Itoero    41
On ‎1‎-‎11‎-‎2017 at 0:52 PM, Strange said:

Seriously.

Photons cannot be accelerated and "packet of energy" is a pretty poor pop-sci description. But it is in line with you just making stuff up as usual.

Then perhaps you should react to what I say. I did not say a photon can be accelerated. A photon is accelerated energy.   Something can't have speed if it's not accelerated. Acceleration creates speed.

 A photon is energy, how is that pop-sci?

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Strange    2543
12 minutes ago, Itoero said:

I did not say a photon can be accelerated. A photon is accelerated energy.

It can’t be accelerated but it is accelerated? Right. 

Acceleration implies a change of speed. Photons only have one speed. They do not accelerate. 

13 minutes ago, Itoero said:

A photon is energy, how is that pop-sci?

A photon is not energy. It is a quantum of the electromagnetic field and has energy, as does a bucket of hot water or a falling rock. So, if a photon “is energy” then so am I. 

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Itoero    41
1 hour ago, Strange said:

It can’t be accelerated but it is accelerated? Right. 

Acceleration implies a change of speed. Photons only have one speed. They do not accelerate. 

 

1 hour ago, Strange said:

A photon is not energy. It is a quantum of the electromagnetic field and has energy, as does a bucket of hot water or a falling rock. So, if a photon “is energy” then so am I. 

You can excite an atomic electron to a higher energy state. After a while, they come down to their natural energy state (electrons can't stay excited for long). But, the loss of energy needs to be compensated for by a release of energy, which is done in the form of a photon.

The releasing of the energy goes along with an acceleration which forms a photon.

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swansont    6251
1 hour ago, Itoero said:

Then perhaps you should react to what I say. I did not say a photon can be accelerated. A photon is accelerated energy.   Something can't have speed if it's not accelerated. Acceleration creates speed.

 A photon is energy, how is that pop-sci?

A photon has energy. To say it is energy is pop-sci mangling of the physics. Energy is a property, not a substance or entity.

21 minutes ago, Itoero said:

You can excite an atomic electron to a higher energy state. After a while, they come down to their natural energy state (electrons can't stay excited for long). But, the loss of energy needs to be compensated for by a release of energy, which is done in the form of a photon.

The releasing of the energy goes along with an acceleration which forms a photon.

Where is the acceleration?

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Itoero    41
26 minutes ago, swansont said:

A photon has energy. To say it is energy is pop-sci mangling of the physics. Energy is a property, not a substance or entity

You can excite an atomic electron to a higher energy state. After a while, they come down to their natural energy state (electrons can't stay excited for long). But, the loss of energy needs to be compensated for by a release of energy, which is done in the form of a photon.

How is a photon not just energy? In this example the energy that forms a photon was a property of an electron.

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swansont    6251
12 minutes ago, Itoero said:

You can excite an atomic electron to a higher energy state. After a while, they come down to their natural energy state (electrons can't stay excited for long). But, the loss of energy needs to be compensated for by a release of energy, which is done in the form of a photon.

Sure (though "can't stay excited for long" is a matter of what you mean by "long"). Photons have energy.

12 minutes ago, Itoero said:

How is a photon not just energy? In this example the energy that forms a photon was a property of an electron.

Photons have spin, too, for instance.

There is nothing wrong with saying that the energy of the excited atom (or electron) is now with the photon, but the photon is not made of energy.  

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Itoero    41
1 hour ago, swansont said:

There is nothing wrong with saying that the energy of the excited atom (or electron) is now with the photon, but the photon is not made of energy.

Why is it not made of energy?

 

1 hour ago, swansont said:

Photons have spin, too, for instance.

Yes but isn't spin a property of energy?

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StringJunky    1511
1 minute ago, Itoero said:

Why is it not made of energy?

You can't take a photograph of energy but you can of something that has it. It does not have independent existence, just like  'length' doesn't.

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swansont    6251
1 hour ago, Itoero said:

Why is it not made of energy?

Because energy is not a substance.

Quote

Yes but isn't spin a property of energy?

No. Spin is angular momentum. There's no inherent relationship between the two. No matter what the energy of a photon is, the spin will always be 1.

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Mordred    930

Nothing is made up of energy.  It is a property not a thing.

"energy is the ability to perform work" nothing more

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Strange    2543
On 14/11/2017 at 5:16 PM, Itoero said:

The releasing of the energy goes along with an acceleration which forms a photon.

Yes, a photon has energy. We agree on that. But the only acceleration here is a (tiny) recoil of the atom. 

21 hours ago, Itoero said:

Why is it not made of energy?

For the same reason it is not made of spin or momentum or wavelength. These are all just properties of a photon. Other particles have energy, they are not made of energy either. 

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