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On the Lighter Side => New Theories => Topic started by: Professor Mega-Mind on 07/06/2020 21:44:30

Title: Is it possible to have a space drive using reflecting light?
Post by: Professor Mega-Mind on 07/06/2020 21:44:30
En-lightened Gentlemen ;
In relation to altered frequency of light :
I put forth a variation of the classic experimental conceptualization involving opposed mirrors , and a perpetually reflecting light-beam between them . In theory , such a beam will produce thrust/recoil each time it strikes a mirror. The static power/thrust ratio is 6.7-Nt. per gigawatt . This is accompanied by a minuscule drop in the power of the reflected light-beam . Millions of such back-and-forth bounces would use up the bouncing light , and yield a total thrust millions of times more than if the light-pulse/beam had only bounced once . In otherwords , the tremendous energy contained in the light-pulse would be used to propel the mirrors in a manner far more efficient than a simple photon rocket .
The derivation of this architecture being examined here is the "Mirror-Wheel" one . IF we have a paddle-wheel structure , rotating at an angular velocity of %10 lightspeed , and a 1-GW lightbeam striking it , what is reflected back ?  The answer is a lightbeam with a frequency of %90 that of the initial striking beam . This means that the returning .beam contains less than %100 of the energy that the initial beam did . This means that , similar to particle-accelerators , the lower-frequency e-m waves propel the matter they impact more efficiently . That in turn , means that the "push" upon the .wheel is stronger than the recoil generated by the e-m emitter . Constant absorption and reemitting of the reflected e-m will perpetuate this effect , consuming the emitted e-m , while generating a net-push in the direction of the mirror-wheel .
*If any of the above participants can offer constructive criticism of this topic-relevant thought-experiment , your input is quite welcome .
Reflecting-Laser Demonstration :
》To compare and contrast this
R-D mechanism with others , read ;
Discussion on Reactionless Drive (extracted) .;topicseen#new
》》For related discussions :
Red-shift of reflected light ?;topicseen#new
*.Addendum : Conceptually , this mechanism is analogous to that of aeronautical engines . They highly energize air , in order to make it act like ground . The indicated R-Ds however , energize light , in order to make it imitate air .
>The old adage is true ; given enough power , even bricks can fly !
》The Hard-Core Optical Physics
Author : Rhadi I. Khrapko , 2/24/17.
Optik - International Journal for Light and Electron Optics .
Title : "Reflection of light from a moving mirror" . 

Title: Re: Red-shift of reflected light?
Post by: Professor Mega-Mind on 08/06/2020 00:31:29
Yes , you are correct . 
That is the basis of the paradigm that was above . Given a paddle-wheel design , with many mirrors instead of paddles , and rotating at .1c , do you get a more significant transfer of that 1gigawatt to the structure , than if you have no wheel rotation ?
**Example : During a 1-gigawatt em. pulse , a target mirror experiences a push of ~2-lbs . Each photon in that pulse undergoes a .0001% drop in energy . If that photon strikes a mirror receding at 10% of lightspeed , then it returns with only 90% of it's original energy content . This immediately implies that the other 10% went into pushing the fast-rotating paddle-wheel mirror . Ten-percent of 1-gw. is 100M.watts ; an absolutely huge number when applied to efficient propulsion-systems !
The likely explanation for this is the prolonged dwell-time of the photons upon the receding mirror . The longer contact-time allows the photons to push against the mirror for a much longer time-period , thus greatly increasing the efficacy of the energy-transfer to the mirror.
*This effect is reminiscent of the Compton-Effect with H.E.X-rays .
**Ref : 
>Focus on elastic collisions between dissimilar masses (lighter objects impacting heavier ones) .
》》Continuation at NSF thread :
Is it possible to have a space drive using reflecting light ?
》In-depth explanation @ thread :
Discussion on Reactionless Drive (extracted) .;topicseen#new
Also : 
Author : Viktor Toth
Title: Re: Is it possible to have a space drive using reflecting light?
Post by: Kryptid on 08/06/2020 04:28:12
In order to keep a light beam bouncing millions of times between two mirrors, the alignment between the mirrors would have to be extraordinarily precise. The further apart the mirrors are, the more precise the alignment would need to be.

I don't understand how your paddle wheel idea works. Given that you were talking about light reflecting between two mirrors, are you talking about light reflecting between two paddle wheels? It would be extremely hard to spin a paddle wheel up to 10% of the speed of light in the first place. The larger it is, the harder it would be. This would not only be due to the energy required, but also the finite tensile strength of the material that the wheel is made of. Centrifugal force would rip it apart if it spun too fast.

Let's consider a wheel with mirrors composed of carbon nanotubes one centimeter long, one centimeter wide and one millimeter thick. That would be a volume of 0.01 cubic centimeters. Carbon nanotubes have a density of about 1.3 grams per cubic centimeter, so the mass of each mirror is 0.013 grams (1.3 x 10-5 kilograms). Giving this value as the mass located at the center of the mirror (0.5 centimeters/0.005 meters out from the central hub), the resulting centrifugal force for spinning at 10% the speed of light (29,979,245.8 meters per second) would be:

Force = mass x velocity squared divided by radius
Force = ((1.3 x 10-5) x (29,979,245.8 )2)/0.005
Force = ((1.3 x 10-5) x (8.9875518 x 1014))/0.005
Force = 11,683,817,323.6/0.005
Force = 2.3367635 x 1012 newtons

This force is exerted over a cross-sectional area of 1 cm x 0.1 cm = 0.1 cm2 = 0.0001 m2. 2.3367635 x 1012 newtons / 0.0001 square meters equals a pressure of 2.3367635 x 1016 newtons per square meter. The ultimate tensile strength of carbon nanotubes is theoretically estimated to be 200 gigapascals (2 x 1011 newtons per square meter). So the nanotubes would be forced to endure stresses over 100,000 times higher than what would be required to break them.

If a light beam struck a paddle that was moving towards the light source, it would actually blue shift the light instead of red shifting it. In the process, the spin of the paddle wheel would slow down because the energy in the paddle would be transferred to the light.
Title: Re: Is it possible to have a space drive using reflecting light?
Post by: Bored chemist on 08/06/2020 18:30:13