[Bored chemist]

Put 1GW of energy into a firehose-size stream of water .  Result ? You cut buildings in half . 
Put 1GW of energy into a firehose-size stream of EMR .  Result ?  Buildings laugh at you .

Utter nonsense, even a kilowatt or so of laser power would damage a building and a megawatt would cut a building in half.

Why posts something which is so obviously wrong?
Is it because you have yet to understand that energy and momentum are not the same thing?

[Professor Mega-Mind (OP)]

...."firehose-size stream of EMR".
I could say the same .
You continue to underestimate and misrepresent me , Year B.C.

[Bored chemist]

...."firehose-size stream of EMR".
I could say the same .
You continue to underestimate and misrepresent me , Year B.C.

A laser beam is a stream of EMR. "firehose sized" is a bit meaningless but a typical hose is about 50mm diameter
A million watts over that area is 500,000 KW/m^2
Things typically catch fire at about 10 KW/m^2
So, a 1 MW "firehose-size stream of EMR" is tens of thousands of times  more power density that is needed to burn stuff.
It would cut a house in two.


Why are you trying to pretend it wouldn't?

[Professor Mega-Mind (OP)]

Dood ,
 I'm talking about a serious fire-hose , like 5 or 6 in. diameter .  That's about 100KW per sq. meter , or 2K× YOUR ignition threshold .  My mirrorized surfaces shrug that off no prob !  My point was about impact , not hot-foot , anyway !
P.M.

[Bored chemist]

OK, so we have a 6 inch hose. 3 times the diameter, so 9 times the area.
That's a 9 fold reduction in power density so it is about 50,000 KW/M^2
That's about 5000 times the typical ignition power density.
(It's not "MY" ignition density, it's a typical value from the web. Pretending that it's something I invented just makes you look even sillier).

A sliver mirror reflects about 98 to 99 % of  the light and absorbs about 1 or 2%
1% of 5000 times enough to destroy stuff is still 50 times enough to destroy it.

Then there's the fact that the original nonsense you talked about was a GW not a MW, so there's 50,000 times more power than is needed to cu t through stuff.

And then there's your delusion that houses are made of mirrors.


No matter what drivel you add now, this will remain nonsense.

Put 1GW of energy into a firehose-size stream of EMR .  Result ?  Buildings laugh at you .

Why not just admit that you have no idea what you are talking about.

[Professor Mega-Mind (OP)]

My houses saw you coming a mile away . They have special , military-grade mirror-siding panels , with cooling channels running through them .  The paper-igniting value helps there too !  They now laugh at the slight breeze that briefly warms them a bit , but secretly quiver in fear at the thought that you might start injecting moles of ions into the EMR stream !
I admit , I'm laughing too !
P.M.

[Bored chemist]

I'm clever enough to wait until it rains.
The water will screw up the mirrors.
At those power densities a speck of dust would result in almost instant destruction of your house.

So your original point was still absurd.

Why not just admit you don't know what you are on about?

[Professor Mega-Mind (OP)]

My original point was hitting power , so how hard does your laser hit , even if it DOES burn my houses down ?  I know mine stops Donald Sutherland at the bank entrance !
P.M.

[Bored chemist]

My original point was hitting power ,

And I addressed it a while ago.
https://www.thenakedscientists.com/forum/index.php?topic=75294.msg560838#msg560838

Why do you keep posting nonsense?

[Kryptid]

If it was true that Compton scattering gave more momentum to an electron than the original photon had, then that would have been a verified instance of a violation of conservation of momentum. Arthur Holly Compton would then have become famous for falsifying conservation of momentum. Yet here we are, 95 years later, and physicists are still comfortably using the conservation of momentum. So obviously, Compton scattering doesn't break the laws of physics and therefore the principle behind your engine's function is based on false premises.

[Professor Mega-Mind (OP)]

I said "energy" not momentum .  Study the associated graphs .  However , even if it were half , the electrons would STILL gain relativistic velocity , and STILL hit like a HALF stick of dynamite !  Think of it as unseen energy precipitating out of solution , then being used by some creative bastard ( like me ) . 
 In regards to momentum , I don't see you accounting for the  momentum of the EMR's internal components .  Physically , the exchange is similar to a light-weight billiard ball hitting a heavier one .  It bounces back with far less kinetic energy , having transferred much of it to the heavier ball .
Sometimes , nature has tricks too !
P.M.

[Kryptid]

I said "energy" not momentum . 

Which is why you don't understand why you're not going to get extra force just because you put electrons in the way of the laser beam. Momentum cannot be ignored when it comes to the physics of collisions.

However , even if it were half , the electrons would STILL gain relativistic velocity , and STILL hit like a HALF stick of dynamite !

Only if the laser beam itself hits like half a stick of dynamite. The laws of physics won't allow it to be any other way.

Think of it as unseen energy precipitating out of solution , then being used by some creative bastard ( like me ) . 

There is no unseen energy here.

In regards to momentum , I don't see you accounting for the  momentum of the EMR's internal components . 

What internal components? It's made only out of photons and the momentum of photons is easily calculated. It's the Planck constant multiplied by its frequency divided by the speed of light. The momentum of a photon is linearly proportional to its energy.

Physically , the exchange is similar to a light-weight billiard ball hitting a heavier one .  It bounces back with far less kinetic energy , having transferred much of it to the heavier ball .

Momentum is conserved in such a collision, just like it is when a photon hits an electron.

[Professor Mega-Mind (OP)]

Proportional , but absurdly tiny !  This is why it is useless in it's nascent form .  Transferring EMR's great energy content to a mediator with greater mass enables Effective transfers of momentum , instead of useless reflections or absorptions .
Can you hear me now ?
P.M.

[Kryptid]

Proportional , but absurdly tiny !  This is why it is useless in it's nascent form .  Transferring EMR's great energy content to a mediator with greater mass enables Effective transfers of momentum , instead of useless reflections or absorptions .
Can you hear me now ?
P.M.

So are you, or are you not, saying that Compton scattering violates conservation of momentum? Because it sounds like you are.

[Professor Mega-Mind (OP)]

No , I'm saying that it's a trick of nature enabled by the fact that photons are not matter .  They can push matter very hard , they just need the right mediator/translator to enable that .  Remember , you don't need to include spent photons in your equations , since they can be vented with no penalty .  Sounds like a Glowing Light Drive  to me , eh ?
P.M.

[Kryptid]

No

So then you agree that the cloud of electrons does not have more momentum than the beam of light that struck it. That confirms that your engine won't move. If you think that the electrons do gain more momentum than the beam of light had, then you think that Compton scattering violates conservation of momentum. Those are the only two options. Which is it?

[Professor Mega-Mind (OP)]

I think you're trying to fork me , Mr. Chessmatch !  Truthfully , the intricacies of Momentum Laws don't fascinate me .  I'll leave it to you number-crunchers to figure out how the exception to the rule occurred , and how to twist you explanations .  Meanwhile , Reply # 157 still applies ,as a matter of straight visualization , and logic !
P.M.

[Kryptid]

Truthfully , the intricacies of Momentum Laws don't fascinate me .

Then you have no business claiming to have beaten them.

I'll leave it to you number-crunchers to figure out how the exception to the rule occurred , and how to twist you explanations .

You want calculations, huh? Alright.

We'll start with an X-ray photon with a kinetic energy of 1,000 eV. It collides with an electron with 0 eV of kinetic energy. After the collision, the photon bounces back the direction it came with a kinetic energy of 996.1 eV. The electron is knocked in the opposite direction with a kinetic energy of 3.9 eV. So the photon in this instance actually keeps most of its energy. You can confirm this by using this calculator here (you'll want to set the scattering angle to 180 degrees, which results in the highest transfer of energy to the electron): http://www.sciencecalculators.org/nuclear-physics/compton-scattering/

The momentum of a photon is calculated by dividing its frequency by the speed of light and then multiplying that by the Planck constant. So we need to know the frequency of a photon that has an energy of 1,000 eV and one with an energy of 996.1 eV. The resulting frequencies are 241,797,944 GHz and 240,854,932 GHz respectively. This calculator shows this: https://www.omnicalculator.com/physics/photon-energy

The momentum of the photons can be calculated with the following calculator, which shows that they are 5.35 x 10^-25 kg*m/s² and 5.32 x 10^-25 kg*m/s² for the 1,000 eV and 996.1 eV photons respectively: https://www.fxsolver.com/solve/

For an electron with a kinetic energy of 3.9 eV, the velocity is 1,171,264 m/s: https://www.omnicalculator.com/physics/relativistic-ke

The momentum of the electron is calculated by multiplying its mass by its velocity. This is equal to ~1.067 x 10^-24 kg*m/s². So now we can compare the momentum after the collision with the momentum before the collision. Since the photon and the electron are travelling in opposite directions after the collision, the momentum of the photon can be considered negative while that of the electron positive: (1.067 x 10^-24) + (-5.32 x 10^-25) = 5.35 x 10^-25 kg*m/s²). So the momentum after the collision is 5.35 x 10^-25 kg*m/s².

Since the only contribution to the momentum before the collision is from the photon (the electron isn't moving), the momentum before the collision is also 5.35 x 10^-25 kg*m/s² (as shown earlier).

So there you have it. A mathematical demonstration that a photon scattering off of an electron does not increase the total momentum of the system.

[Professor Mega-Mind (OP)]

Dude-man ,
You don't need to torture yourself  (or me) with convoluted formulas !  Just Google up Science Direct : Compton Scattering ; Fig. 6.2 .
This illustrates CLEARLY that for high-energy photons , striking electrons at 180° , the energy transfer amount ( E re max ) does approach 90° !  As I stated before , photons are NOT matter , and their interactions are "quantum" strange .  High-energy photons will raise electrons to relativistic speeds , at this point the depleted photons can be dumped overboard ( GLD ! ) .  The wave of high-energy electrons will hit the target HARD , as opposed to the photon launch side , which had neglegible recoil .  This here is a basic , mechanical system .  It is fairly easy for even a layman to understand , as long as there's no formula-spouting jerk-water spewing wheelbarrows of BS in their face , so that they get intimidated , and give up !  By the way , why the **** are you trying to fool the inventor of this damned thing , are you a masochist , or do you have some rediculous ulterior motive ? 
Alright , this I gotta hear !
P.M.

[Bored chemist]

I said "energy" not momentum

But you are talking about a reactionless drive and both reaction and drive are related to momentum but not, fundamentally, to energy.
Yet again, you have shown that you don't know what you are on about.

You really need to get to grips with the difference.

Think of it as unseen energy

But it isn't real.

then being used by some creative bastard ( like me )

You are being "creative" in that you are making up sh1t.
It isn't true.

I don't see you accounting for the  momentum of the EMR's internal components . 

Your blindness to it isn't our problem.

Physically , the exchange is similar to a light-weight billiard ball hitting a heavier one .  It bounces back with far less kinetic energy , having transferred much of it to the heavier ball .

A light ball bouncing off a very heavy one loses very little energy.
You really need to learn the physics.

Sometimes , nature has tricks too !

It does, but you are mistaken about where to find them.

For example it took ages to convince you that the transfer of momentum is greater when something bounces off a target  than when it sticks to it, even though that "trick" is high school science.

Proportional , but absurdly tiny !

Yes roughly a pound per GW is tiny.
And yet you are proposing to drive a spaceship with it.

enables Effective transfers of momentum

Shining the laser out of a window gives almost perfect transfer of momentum.
Better than "all of it" isn't an option.

Can you hear me now ?

Yes; we hear you loudly shouting nonsense.
And we wish you would stop, because this gibberish undermines the point of the board which is to communicate science.

Truthfully , the intricacies of Momentum Laws don't fascinate me . 

Then leave the discussion to those who, if not fascinated, at least understand them.

I'll leave it to you number-crunchers to figure out how the exception to the rule occurred

First of all, you need to show that an exception happens.
So far all you have done is fail to understand basic science.

Meanwhile , Reply # 157 still applies ,as a matter of straight visualization , and logic !

Post 157 is utterly wrong; you already accepted that.
 A GW laser would trash a house (even if you made it out of mirrors).

You don't need to torture yourself  (or me) with convoluted formulas ! 

You have made that mistake all along
You need to do the maths to get the right answer.

As I stated before , photons are NOT matter , and their interactions are "quantum" strange .

The higher the energy of a photon the more like a billiard ball it behaves.
We know about the quantum strangeness- (it seems you don't) but we also know that quantum physics also includes the conservation of momentum.

It is fairly easy for even a layman to understand

And it's wrong.

as long as there's no formula-spouting jerk-water spewing wheelbarrows of BS in their face ,

You are the one spouting bull.
The maths, which you are too scared to do,  proves it.
Is that why you won't learn  the maths- because you know, deep down, that it will show why you are wrong?

why the fruck are you trying to fool the inventor of this damned thing

As explained, I point out mistakes like yours in order to ensure that what people read here is science rather than nonsense.

or do you have some rediculous ulterior motive ? 

You know why I point out your errors.

Why do you keep on repeating them?