# E-mail from Ron Pearson to New Scientist (July 4, 2003): Flaws in Physics - WHY PHYSICISTS SHOULD LISTEN TO ENGINEERS

2003-July-04 Filed in: Science

### SOLAR SAILING IS FEASIBLE!

Thomas Gold of Cornell University says in the 5 July issue of "New Scientist" that:

"Solar Sailing breaks the Laws of Physics".

Gold has ignored the Doppler effect. Consider a sail moving directly away from a source of light and so arranged as to direct the reflection back to the source. It is true, from a frame of reference moving with the sail, that the energy of the reflected photon will appear equal to that of the incident photon with its momentum equal but oppositely directed. However, viewed from the source the received photon will have its wavelength increased by the Doppler effect. A further equal increase applies to the reflected photon as seen from the source. The total wavelength increase corresponds to a reduction in both energy and momentum of the reflected photon with the source as reference frame. The rate of change in momentum of all photons reflected is equal to the force on the sail and the wavelength increase (red shift) corresponds to an energy reduction exactly equal to the work done on the sail.

### CROOKE'S RADIOMETER EXPLAINED

In "Solar sailing breaks the laws of physics" (New Scientist 5 July 03 p 16) Steven Soter says the Crooke's radiometer spins the wrong way. He deduces that something must be wrong with our understanding of the mechanics of photons. Crooke's radiometer has radial vanes that reflect light on one surface but absorb it on the opposite blackened one. The change in momentum of reflected light is double that of absorbed light and so the rotor is expected to spin in a direction with black surface leading. A simple mathematical analysis based on established physics shows that the rotor will turn in the opposite direction: the one observed. Hence no change to physics is needed! If q is the number of photons per unit time per unit area, impinging from a given radial direction, S the area of the vane, p the momentum per photon, R the mean radius and omega the angular velocity of the rotor, then calculus yields a simple equation for the power W produced by optical reflection and becomes: W = q S p R omega/(2 pi) [1]

For the black absorbing surface the power is half this value and is opposed so at first sight the optical reflecting surface seems to provide the net driving force. However, the heating effect of the absorbed photons has been ignored. The vanes will heat up and, when equilibrium is reached, re-radiate all absorbed heat as infra red from only the blackened surface. The reduced momentum per photon is compensated by an increase in number. Now, however, the emission is randomly directed and that means a "cosine law" operates. This makes the average momentum normal to the surface 2/3 of that given if all photons were emitted normal to the surface. The average force acts continuously and the analysis gives the power from this source as: W= q S p R omega 2/(3 pi) [2]

When added to the absorption power the total becomes: W= 1.5 q S p R omega/(2 pi) [3]

Hence after the vanes have had time to heat up and by comparing [3] with [1] it is seen that the black surface dominates and so pushes the rotor in the direction observed!

### WHY PHYSICISTS SHOULD LISTEN TO ENGINEERS

Gold expands his dismissal of the feasibility of solar sailing on his website:

www.arxiv.org/html/physics/0306050

but his logic is clearly flawed. In the New Scientist article of 5 July 03 Jeffrey Lewins, thermodynamics expert at the University of Cambridge is sceptical. Steven Soter, astronomer at the Hayden Planetarium in New York, is open to Gold's idea and questions the momentum rules governing photons quoting William Crooke's radiometer that rotates in a direction opposed to what is expected from solar sail theory. Louis Friedman, the NASA project's director, is quoted as being undaunted by Gold's critique, insisting, "Solar Sailing is feasible".

However, we now come to the most important feature this article highlights. None of these eminent people, nor the assessors of "New Scientist", have spotted the flaw in Gold's logic. The mathematical expertise of the physicist is admired and not denied but the engineer can help with the simple things and so could have a useful part to play. This flaw would be immediately obvious to any mechanical engineer, especially one with experience of turbine design, since the effect is analogous to that used to extract energy from a fluid by a moving rotor. I think most engineers would also have they appreciated the flaw in Soter's deduction that since the Crooke's radiometer spins the wrong way something must be wrong with the physics. Soter is an astronomer at the Hayden Planetarium in New York and so is likely to have the qualifications of an astrophysicist. These are classic examples illustrating the need for engineers to be incorporated into teams of physicists. Physicists continually miss the simple things that engineers spot immediately!

Ron Pearson

Pearson provides the theory needed to explain not only telepathy, but also the entire spectrum of the so-called 'paranormal' as testable real effects. It also covers non-locality that no physicists have explained.

Publications by Ron Pearson

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An Exact Classical Mechanics leads toward Quantum Gravitation - Ronald PearsonThis pamphlet suggests that misconceptions in classical mechanics are responsible for blocking progress in physics. Refinements are described which spill over into quantum theory and appear to provide answers to vexed questions. For example, it leads to alternatives to both special and general relativity which match the achievements of both. Unlike relativity, however, the new solution is fully quantum-compatible, being consistent with the concept of the quantum vacuum. |

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