Reproducing the Velador Experiment

(Last Reviewed 6/5/07) 

Experiment Background and Rationale 

In the March 2, 2007 issue of the Citizen Scientist, an article by Dr. Lance Osadchey presented results from an experiment he had begun in 2003.  Using an instrument he calls a Velador (from the acronym Velocity Assessment and Detection by Optical Radiation), he claims to have found experimental evidence for an absolute vector reference.   

The Velador is described in a followup article for the April 6, 2007 issue and at Dr. Osadchey's web site. 

The Velador’s camera and laser source are fixed with respect to the support beam, and all move in the same frame.  As long as the weight vector can be kept constant and the instrument is not accelerated, then the point of incidence of the laser beam on the CCD chip should not change with the orientation of the Velador.  The light emitted by the laser should always travel the same path across to the camera, regardless of which way the beam is pointing.

According to Dr. Osadchey’s measurements, the laser beam is deflected differently at different orientations.  This deflection varies predictably according to which direction the Velador is pointing, a result at odds with current theory.

In itself, deflection of a laser beam en route from the laser to the camera is not physically impossible.  It can be done by moving/rotating the camera out of the way as the light is in transit (as seen in laser gyroscopes, which use the Sagnac Effect to measure circular motion).  Any deflection due to the Earth’s rotation moving the camera will be very small – too small for the Velador to measure reliably.  So, while the Sagnac effect could conceivable produce this observation under some circumstances, there is no obvious inherent source of acceleration on the Earth’s surface that is large enough to account for the observed deflection.   (Because care is taken not to allow the weight to shift between orientations, gravitational acceleration doesn’t shift either.)

The absence of an understood cause leaves two potential explanations: 1) Dr. Osadchey is actually “observing” a systematic error in his measurements (the Velador’s weight is shifting and he doesn’t realize it, the Velador is bending under thermal stress, thermal refraction is bending the light path, etc.), or 2) Dr. Osadchey is observing something new to science. 

Experiments looking for similar displacement effects (as tests of the theory of relativity) have been performed using interferometers, which are even more precise than the Velador for measurements of rotation or other displacements along the beam path, but are not particularly sensitive to lateral displacements.  No similar experiment of comparable sensitivity has ever been performed to look for this lateral displacement effect in coherent light using the same method.  Thus, this is an original experimental design, and there is no way to be certain of the actual explanation for Dr. Osadchey’s results without repeating the experiment.

A cost estimate indicated that the experiment could be done for approximately US $100 (ultimately almost $150, after design improvements).  If I didn’t spend it all at once, that was within my budget for the month, and (whether Dr. Osadchey’s claim was proven out or not) at the end I would be the proud owner of one of the world’s largest strain gauges.  I wanted to know if general relativity was correct, and building my own Velador was the fastest way to find out.

So, I began trying to reproduce Dr. Osadchey’s experiment.

Experimental Goals

Because Dr. Osadchey has already observed and reported the effect, I am freed from the responsibility of doing so.  So, I can now idyllically devote my efforts toward proving the null hypothesis.  My first experimental trials will focus on demonstrating the alternate explanation – that Dr. Osadchey is recording some systematic error.  Thus, my goal in this experiment is to demonstrate that eliminating or accounting for the most likely sources of error also eliminates or accounts for the measured effect.  In doing so, I have to be careful to eliminate, reduce or control the error sources without means that would also eliminate or reduce Osadchey’s claimed effect.  (For example, introducing lenses at various points along the light path can reduce the apparent errors by shrinking the image, but could also shrink any apparent motion across the CCD, systematic error or not.)

Dr. Osadchey's claims are based on visual observation of image motion.  Thus, anything that introduces spurious motion or interferes with an observer's ability to interpret motion is a possible source of error.  The most likely error sources, and the ones that I will investigate, are:

1)      Flexing of the support beam as its weight shifts. 

Although Dr. Osadchey is  keeping the beam axis very close to horizontal (he’s got it horizontal to within at least normal tolerances for a house floor – 10cm dip or less per 3m of beam length), the support beam is a three dimensional object and can rotate on two axes while still remaining horizontal.  This means that any coupling between the floor slope (or mount tilt, if using a central bearing) and the support beam can produce a slight shift in weight from side to side as well as up and down.  It’s possible to imagine several geometries for the support beam mount where the resulting shifts in weight as the support beam rises and falls during rotation can produce the very same pattern seen by Dr. Osadchey.  The simplest such geometry is a slope that is perfectly flat and uniform while not perfectly level, for which the beam deflection should vary as a near perfect sinusoidal curve if the support beam is completely coupled to the mount.

I plan to counteract this effect by using a suspended mount for the support beam, the beam swinging like a complex pendulum, so that its attitude along at least one axis is not directly determined by the slope of the floor (or defects in the pivot).  I am also accounting for it by selecting as lightweight a material as practical for the beam (wood), in order that its self weight can be as low as possible.  The beam material should also be selected for the best combination of strength and light weight.  For example, wood is not as strong as steel, but does not bend significantly more under its own weight.

If I observe the same effect but only in the direction corresponding to my setup’s coupled orientation (in this case, vertical motion of the image), then that demonstrates Dr. Osadchey is observing flexure due to a defect in his mount.  My own mount will only be as reliable (or unreliable) as Dr. Osadchey’s for vertical motions, but that can be dealt with later and may not make a difference if the horizontal signal remains clear despite removing any influence from the slope of the floor.

2)      Flexing of the support beam under uneven thermal expansion.

Because the support beam must be relatively large, in both length and cross-section, it is subject to slight thermal bending whenever there is a temperature difference across the beam.  This bending is toward the colder section of the beam, and can mimic the expected effect if the beam is being repeatedly heated and cooled by a heat source as it turns.

I have no plan to actively counteract thermal bending.  However, it can be identified and isolated by proper use of experimental controls.  Heating is not instantaneous, and if I can insulate the support beam enough to slow heat flow, then changes in the timing of the measurements will show distinct differences in the measured effect. 

The measured effect may vary with sidereal orientation (and thus with sidereal time), not just orientation relative to the earth, and I will need to check for that in my analysis as the experiment continues.  However, if the magnitude of the effect also varies with the duration of the experimental trial, then it is almost certainly due to thermal distortion.

Some thermal distortion is inevitable.  Calculations to estimate the magnitude of thermal bending and my initial trials lead me to believe it will not be a serious source of measurement error for a support beam of the size and material I’m using, though.  I have deliberately chosen an insulating material (wood) for construction, and expect any actual thermal deformation to be barely measurable over the time scale of a single trial. 

(I am not yet interested in the long duration trials Dr. Osadchey is currently undertaking as experimental controls.  That comes later, if I can eliminate some of the more basic measurement errors.)

3)      Distortion of the image by thermal refraction.

Temperature differences in the air of the light path can refract the laser beam, causing a false signal.  As with thermal expansion, these can be varied by turning the beam in the presence of a heat source.  Thermal refraction can also be created by inducing air flow through the Velador. 

I plan to counteract this effect by confining the light path to the interior of an insulated tube (through the middle of the Velador), and by sealing that tube against air flow.  This will significantly reduce heat flow across the light path.

I can also account for the refraction by both varying the measurement schedule as a control and by identifying thermal refraction in images.  Calculations and experimental trials to investigate thermal refraction reveal that thermal refraction of the laser beam produces a characteristic pattern (smearing), and can be identified from visual inspection of the images.

If the smearing pattern characteristic to thermal refraction is pronounced in most of the images showing motion, then I will assume that the measured effect is due to thermal refraction.

4)      Measurement error due to false signals.

There is considerable noise (false signals) at the edge of the central peak in each image, making it difficult to assign measurement references.  The apparent size of the central peak will vary according to the measurement method used, the random character of this noise signal, camera performance, and other factors.  This makes the width of this noise region the lower limit of measurement error. 

If the measured effect is smaller than the region of noise at the edge of the central peak, then I will assume a null result regardless of the statistical significance of any individual signal, because below this magnitude a statistically significant signal can result from any slight variation in the intensity of the laser or in the threshold intensity of the CCD cells.

It should be noted that Dr. Osadchey’s measurements already indicate a range of image motion significantly greater than the width of these fuzzy edge regions in his own images.  I remain alert to the possibility, but I already consider Dr. Osadchey’s published results to date to be sufficient disproof of inherent imaging noise as a source of error.