Saturday, May 28, 2011

Geocentrism: Failing Basic Physics...

John Martin attempts a 'Gish Gallop' (RationalWiki) of comments in response to this post (Geocentrism: Does NASA use Geocentrism?).  These questions, and some additional, also appear to be available on John Martin's blog. Most of the comments demonstrate a very poor level of understanding of topics ranging from basic geometry to physics.  This commonly occurs if someone bases their scientific understanding on interpretations of press releases with an incorrect or incomplete understanding of the more fundamental physical concepts. 

It's not clear how many of these were Mr. Martin's own thoughts or some regurgitation of material from another source.  However, considering how many of the answers I readily found online, it is clear that Mr. Martin was incapable of doing even the most basic of research.

Q's referenced in this comment
Dr. Bridgman You asked questions concerning lagrange points and space flight paths using geocentrism. It seems to me that if relativity is correct and the earth can be considered as moving, the calculations are then performed in the usual way and then a transform is completed to a stationary earth inertial reference frame. This would enable the flight path and lagrange points to be calculated. Alternatively a mathematical model of a geocentric universe would have to be constructed and the forces caused by the rotating universe included within the calculations to directly calculate the lagrange points and flight paths. According to GWW such mathematical models have been constructed by physicists.
Let me get this straight, you want to do all the calculations in the appropriate (heliocentric) frames, then use a coordinate transformation (a technique valid between ANY locations) to transform to a geocentric frame.  So far that is okay.

But if you want use this technique to claim that it supports the Earth as a favored position in space, that would be a lie.  This technique will work for any object, whether it be a planet or spacecraft.

Some other implications of Mr. Martin's suggestion:
  • This type of ploy also brings to light the fact that the heliocentrists can work in ANY convenient coordinate system, but the Geocentrists cannot do squat without the heliocentric techniques.  Mr. Martin has basically admitted that Geocentrism claims are useless for any practical problems.
  • This tactic is also used by Geocentrists and other pseudoscientists to evade doing any actual work themselves that would be required of real science.  They want to get by with just saying “We use the heliocentric results done by others and then transform the results to an Earth-centered system and this makes the Earth a favored position“.  This is equivalent to stealing the work of others and trying to re-label it as your own. 
Geocentrists, like many other pseudo-scientists I've confronted on this blog, seem to be nothing but posers.  They want credit and recognition for achievements they have not done.

Many of the questions below erroneously invoke Kepler's Laws.  This is disturbing since Mr. Martin claims a degree in engineering yet apparently could not comprehend how many of these issues were covered in the previous post, Geocentrism: Does NASA use Geocentrism? Some of these errors are equivalent to using idealizations of a round earth and invoking the fact that the Earth actually deviates from perfectly round as a basis for claiming that the Earth is flat, or trying to claim the Gas Laws (wikipedia) are incorrect by applying them to the thermal expansion of liquids and solids.

Kepler's Laws (Wikipedia) are actually a special case of Newton's laws and gravitation LIMITED TO THE CASE OF ONLY TWO BODIES (Wikipedia).  The instant the question involves more than two bodies, Kepler's Laws become, at best, an approximation.  In the case where the system is dominated by a large mass with additional bodies of much smaller masses (such as the Sun being the dominant mass of the solar system), it is still possible to develop perturbation expansions where the orbit is close to Keplerian, but the Keplerian orbital elements (wikipedia) undergo a slow variation with time.  This is the method used in algorithms such as VSOP87 (Wikipedia)
If relativity is correct at least according to inertial reference frames, then a rotating and moving shell of stars will produce the same forces on a body as a rotating and moving earth against the fixed stars. Some questions for your consideration –
Q1 - according to Kepler’s first law, See more... “The orbit of every planet is an ellipse with the Sun at one of the two foci.“, yet the center of mass of the sun is always moving around the solar system barycenter. Therefore, as the foci of the planets ellipse moves, does this therefore invalidated the first law, or does the entire ellipse move with the moving foci at the center of the sun?

Q2- If the planet actually orbits the solar system barycenter, why then does Kepler’s first law say otherwise?
Q1, Q2:  Failure to understand basic mechanics to the two-body problem (wikipedia).
Q3 - Doesn't the solar system barycenter exclude the center of the sun as being a foci of the planets elliptical orbit?
Q3: Failure to understand basic geometry.  It is not a problem when the 'centers' can also move, including the Earth's center.  Even Ptolemy's model did this.
Q4- If Kepler’s first law is used in planetary flight paths, this means the solar system barycenter must be ignored, which thereby seems to invalidate Newton’s laws of motion around a common barycenter. Please comment.
Q4:  Failure to understand basic mechanics of the Two-body problem (wikipedia). 
Q5- Why do Kepler’s laws assume all planets have an elliptical flight path, yet when we take into account the Earth-moon system, the earth moves around the Earth - moon barycenter every month whilst moving along its orbital path around the sun. If the trace out the flight path of the earth relative to the center of mass of the sun as the foci of the ellipse, the earth cannot possibly be traveling in an ellipse, but must move through “absolute space“ in a flower pattern centered on the solar system barycenter. As the earths flight path does not fit into the elliptical orbit pattern required by Kepler’s laws, how are Kepler’s laws used to accurately determine the flights paths of other planets relative to the earth?
Q5:  Misapplication of Kepler's Laws to a three-body system (Sun-Earth-Moon).  Failure to understand basic mechanics of the 2-body and N-body problem, basic geometry.,
“Regular Keplerian motions in classical many-body systems“ by Eugene I Butikov
Q6 - If the earth is orbiting around the Earth-moon barycenter every month, why don’t we see the apparent motion of the sun around the earth vary in velocity as the earth gains and loses a velocity component due to its motion relative to the “fixed” sun? In other words – during the monthly cycle there is a time when the earth must orbit in a prograde manner relative to the sun, when orbiting the earth –moon system. Later during the month, the earth continues its earth-moon barycenter motion and must move in a retrograde motion relative to the fixed sun.
Q6: Trajectories look different in different coordinate systems, especially when those coordinate systems vary in time. LRO in Earth Centered and Moon Centered Coordinates

Q's referenced in this comment.
Q7- How are these relative prograde and retrograde motions of the earth on a monthly basis taken into account in the flight path calculations?

Q8- How are the calculations consistent with Kepler’s laws, when the earths flight path through space is not an ellipse, but a complex flower shape?
Q7, Q8: Failure to understand basic geometry.  This is a far worse problem if you try to do an interplanetary trajectory calculation in a 'Geocentric' frame.  That is the problem Geocentrists must solve.  Many references to how this is actually done were linked from the previous post (Geocentrism: Does NASA use Geocentrism?)
Q9 - According to Kepler’s laws, the earth orbits the sun every year in an ellipse. Accordingly the velocity of the earth varies from 30.287 to 29.291 km/s, yet the earths orbital velocity around the earth-moon system is approximately 0.012km/s. This means that if we take into account the monthly orbit velocity of the earth around the E-M barycenter, the earths velocity around the sun will vary from 30.287+-0.012 to 29.291+-0.012, which means the earths orbital velocity around the sun does not comply with Kepler’s laws. How is the flight path of the earth and planets relative to the earth calculated when the earths flight path around the sun does not comply with Kepler’s laws?
Q9: Misapplication of Kepler's Laws to a three-body system (Sun-Earth-Moon). 
Q10 – If the earth See more... moves around the E-M barycenter every month, why don’t we observe a monthly parallax of the sun?
Q10: Failure to understand basic geometry and trigonometry.  Barycenter offset of Earth-Moon system creates an angle of about 4,640 km / 149,600,000 km = 3.10e-5 radians = 1.78e-3 degrees = 6.40“ of arc.  Equivalent Earth rotation =  1.18e-4 hours = 0.426 seconds is the equivalent variation in time.  This is if you just consider the Sun, Earth & Moon.  While an angle and time of this size could probably be readily measured at a ground-based observatory for a point-like object at night, I invite you to measure this angle to the timing accuracy required, in daytime, with changing atmospheric conditions, for an extended object like the Sun.
Q11 – The sundial is constructed using the equation of time which excludes the motion of the sun around the solar system barycenter. As the sun moves quite a large amount over many years, as shown in this video, - why is the suns motion ignored in the equation of time? Please provide the calculations to demonstrate the suns motion around the solar system barycenter can legitimately be ignored in the equation of time.
Q11: The analemma and equation of time are perturbed due to motions of all the planets around the center of mass and they vary from year to year.  This means you cannot define a precise uniform time scale based on the motion of the Sun and why many of these equations refer to the motion of a mean Sun which ignores these variations.  Therefore we move over to time systems based on atomic clocks, calibrated for different frames of reference where appropriate.  A number of alternative time scales (with conversions and adjustments between them) have been developed to solve these problems:
To be continued...

    Saturday, May 21, 2011

    Balticon 45

    Other activities and priorities have been slowing my post frequency.

    On Memorial Day weekend, I expect to be at the Balticon Science Fiction convention in Baltimore, Maryland.

    For part of the convention, I will be at the table for the National Capital Area Skeptics.

    I'm not on the schedule as a speaker, but I have been asked if I could fill-in should there be a last-minute cancellation.  We shall see...

    Saturday, May 14, 2011

    A Science Event in the Maryland/D.C. Area

    (I TRIED to post this earlier this week but Blogger being partially offline did not help.)


    Goddard Space Flight Center will be operating an open house on Saturday, May 14, 2011.

    There will be presentations by engineers and scientists, tours of spacecraft facilities and technology demonstrations.

    Saturday, May 7, 2011

    Quantized Redshifts XI. My Designer Universe Meets Some Data and What's Next...

    When we last left our quantized redshift discussion (Quantized Redshifts. X. Testing Our "Designer Universe"), I had just plotted the histogram, sampled radially, of a statistically uniform cosmos sampled to a finite limiting magnitude.  This was to simulate how surveys of such a cosmos would appear to astronomers on Earth.  I concluded with a plot of survey sampling the universe in redshift (z).
    Click to enlarge
    Note that I started with a UNIFORM distribution of points/galaxies distributed through the volume and then selected them based on the points brighter than the limiting magnitude of the telescope from a position inside the volume.  If the volume were sufficiently large, I would see this same form regardless of where I placed the observer.

    The purpose of these exercises was to develop an understanding of how this type of distribution can form. We can now examine the behavior of this histogram with new insights.

    For z<0.08, the number of galaxies we see is dominated by the fact that we are counting in a steadily larger and larger sphere.  Each point in the histogram is the number of galaxies in a thin spherical shell of thickness delta_z, and radius z, which is increasing as z^2 as we observe deeper into space.  However, beyond about z=0.08, we start missing the faintest galaxies because they are fainter than our telescopes can detect, and the counts begin to drop, relative to the number we expect to see.  This happens in spite of the fact that we are still seeing a larger and larger volume of space.  In a perfectly uniform (and infinite) universe, an observer at any location would see a similar histogram of galaxy counts in distance space (and z-space if they are correlated).

    If the graphic looks at little familiar, it might be because it is very similar to the histograms of the galaxy distributions that come from deep sky galaxy surveys and appear in a number of papers.  

    For comparison, we can plot our model together with a couple of the more well-known deep survey datasets.  Because my model universe was assembled using very rough numbers, my histogram curve is a little off, but I can adjust the parameters to generate a better match (or 'fit') with the data.  We plot this type of curve along with the profiles of the 2dFGRS (blue) and SDSS DR8 (red) surveys.  I've normalized the galaxy count on all the samples to make a more reliable comparison.  While not an exact match, the general profile illustrates some of the mechanisms that drive the large-scale shape. 
    Click to enlarge
    We see a similar general distribution, but the real surveys have substantially larger variations than our uniform 'mock catalog'.  The two real surveys also have some significant differences with each other.  While there is a small overlap in the sky covered by 2dFGRS and SDSS DR8, these two surveys sample different sections of the sky.  This is evidence that the universe is NOT spherically symmetric around the Earth since the galaxy distribution has significantly different structures in different directions in the sky.  SDSS has an additional 'hump' at z=0.35 (I suspect this is due to a deep volume-limited survey of red luminous elliptical galaxies that was part of SDSS.  This also suggests that SDSS is a magnitude-limited survey).  2dFGRS has a significantly larger peak near z=0.12 which is not in SDSS.

    We can smooth the fluctuations by choosing larger bins for the data, for example, for bins about 20x larger, or delta_z = 0.02, we get
    Click to enlarge
    Remember, the red curve corresponds to a perfectly uniform universe with some statistical noise sprinkled in, while blue and green correspond to real galaxy surveys.  While not proof, it is certainly evidence that the cosmos is fairly uniform on large scales.

    An alternative model might include is that we are seeing the edge of the distribution and that the number of galaxies is actually dropping to zero because we are seeing back to a time when galaxies were just being formed and the density of galaxies was lower.

    Note this has spherical (isotropic) coverage from observer position.  Most surveys cover only a fraction of the sky at best, and deviations from this mean curve could be due to large structures dominating one direction which are not spherically distributed around the observer.

    What Next?
    There are a number of ideas I'm exploring for additional posts in this series, but I want to take some time to check them carefully.

    - Power Spectra - 1-D vs 3-D data.
    Currently, my computations of 3-D power spectra of my mock catalogs are notoriously slow.  Catalogs as small as 50,000 galaxies can take several days to process into a power spectrum at reasonable resolution.  This has made attempts at code validation difficult. I'm looking at multiprocessing and other techniques to improve this.  The big surveys use various complex mathematical techniques to make the computation more manageable - but I will try to avoid this, both for clarity and because the techniques would require substantial coding and debugging and explanation time (note that the FFT is faster than the standard Fourier transform due to a mathematical trick).  However, there are numerous concepts that can be addressed using the mathematical theorems of the Fourier transform and power spectra in the meantime.

    - Slicing the survey data.
    Because all these datasets are publicly available, I have samples of the nearly quarter million galaxies in 2d FGRS and over 800,000 galaxies from SDSS DR8.  These two surveys provide some really nice data for visualization.  For example, if galaxies were really concentrated in concentric spheres around the Milky Way Galaxy, this should be easy to illustrate by selecting subsets of the surveys in any given direction (choosing sections of the sky of equal angular area).

    - Improving the mock catalog.
    There are many effects of real physics that are not included in my simulation, which are integrated into professional mock catalogs (see Creating synthetic universes in a computer by Carlton Baugh).  Some of the effects I have not included are:
    1. The redshift, z, is not a linear function of distance, r, over the full range
    2. Galaxies interact under gravity, altering their motion with respect to the Hubble flow.  This is sometimes called 'clumping'.  The gravitational attraction of the galaxies gives them motions not perfectly carried in the Hubble flow, creating a situation where galaxies at a given distance, r, will have a redshift, z, different than indicated by the Hubble relationship.  This is also responsible for the "Finger of God" artifact (wikipedia). (see also Redshift-space Distortions, Redshift-distortions)
    3. Galaxy evolution.  As the stars in a galaxy evolve, the luminosity and spectra of the galaxy will change.
    4. There is an luminosity correction for the galaxy due to how the redshift alters the amount of light in the visible part of the spectrum - photons from the red end of the spectrum get shifted into the infrared and photons from the ultraviolet end of the spectrum are shifted into the violet.  This is also called the k-correction (wikipedia).
    While I don't expect to model a catalog to the fantastic level of detail as presented at Mock Galaxy Redshift Catalogs (paper), I will probably use the mock catalogs available here to test and calibrate some of my codes.  You should check out the figures on this site.  Particularly take a look at the simulations of the SDSS catalog and compare them to some of the actual slices through the real SDSS dataset.  Note that this paper was written some years before the actual data was available.  These mock catalogs started with uniform distributions of points (galaxies) and then let them move under gravitational attraction.

    Sunday, May 1, 2011

    Links of Interest

    The Science of Why We Don't Believe Science
    by Chris Mooney

    This article summarizes a number of experiments and studies from psychology on why it is so difficult to change some people's beliefs.  While the article goes into how personal beliefs can be strongly influenced by an individual's sense of 'group identity', it doesn't really go into how one defines their 'group identity'.  Is it entirely determined by one's social environment, or is it determined more internally.

    Some people ask me why I do this blog when it is very clear that I will never change the belief systems of many of the individuals I confront here.  The short answer is that I don't expect to change their beliefs - I expect to provide the information that can sway the person who is still 'on the fence'.

    One of the more interesting blogs I've started to follow is the dot-physics blog posted by Rhett Allain at Wired magazine.  Many of the articles explore applying physics to everyday things.

    And now I'll take some time to do a little PSA, since I've spent so much time at a dermatologist's office in recent weeks getting little chunks cut out of me.  It's kept me preoccupied and I hope to catch up on the this blog soon.
    Skin Cancer Prevention & Early Detection