Saturday, August 13, 2011

Geocentrism: Laser Ranging Experiments

Mr. Martin responds to "Stupid Geocentrist Tricks" with In Response to Dr Bridgmans "Stupid Geocentrist Tricks". I've already made some reply in the comments to the previous article.

Mr. Martin's response is a collection of nonsense that can only be maintained if one is never required to test their claims against real physical measurements.
Martin: "2. Science has demonstrated physical phenomena occur relative to earth as though the earth was stationary relative to the rest of the universe. As such, the geocentric model alone is the correct model."
All of Mr. Martins 'proofs' of Geocentrism rely exclusively on experiments done on the Earth, while ignoring similar experiments elsewhere in space.
Martin: "If Dr Bridgman denies this problem exists then let him have a look at a similar situation with the lunar laser ranging experiment. According to Dr Tom Murphy the experiment works by the mirror deforming according to relativity theory, causing the laser to bounce back in the mirror frame along a different line from which it entered, thereby the laser returns safely back to the moving earth. A clear indication of the mirror deformation is shown here figure 2, page 2 - http://www.physics.ucsd.edu/~tmurphy/apollo/doc/velocity.pdf"
Here's an upper-level link to a larger collection of Dr. Murphy's documentation of Lunar Retro-Reflector (LRR) experiments.

The Murphy paper discusses the aberration effect that must be considered in lunar ranging. I have already demonstrated that aberration effects have been measured and utilized for navigation purposes by satellites around the solar system (see Geocentrism: Ubiquitous aberrations) so Mr. Martin's claim that this is evidence for a motionless Earth are moot.

The LRR is not the only laser ranging experiment.   I can think of three that have operated, or are operating, around the solar system:
  • MOLA was in orbit around Mars, 
  • LOLA is currently in lunar orbit, 
  • Messenger is at Mercury 
(see Planetary Laser Altimetry). All these instruments operate by bouncing laser signals off the surface of the planet. All operate around the particular planet they orbit as if that planet were the center of the universe, or even as if the instrument itself were the center of the universe. The lasers use the exact same value of 'c' in computing their range from timing even though they are in motion relative to the Earth.  This is as expected from relativity.

If the Earth were truly a distinguished coordinate system as Mr. Martin claims, then you would expect these laser altimeters to operate differently when orbiting another planet. Mr. Martin evades specifying what would be different in their operation. The simple fact is the laser altimeters operate exactly like they do when based the Earth, or Earth orbit, as predicted/expected by relativity.

This is not an idle question.  If there were a way to distinguish a frame of absolute motion, it would be possible to build an actual 'speedometer' to ride aboard a spacecraft, instead of using the complex combination of spacecraft orientation and remote Doppler measurements currently required.  If Geocentrists are correct, they should be able to prove their case by the invention of such a device.

Mr. Martin whines that Dr. Murphy won't respond to him. That is no mystery. People doing real work don't enjoy wasting their work time with Mr. Martin's type of silliness, whereas I do this as a hobby outside my day job.

Mr. Martin cannot produce an experiment operating around the other planets, or in the space between them, that suggests Geocentrism is true. There are many experiments operating in these regions providing evidence that Geocentrism is false.

8 comments:

Anonymous said...

In addition to the challenge of explaining how laser ranging works for solar system objects other than the Earth, Mr. Martin has the challenge of explaining how the Galileo Probe Descent Module was able to communicate with the mothership (the Galileo Orbiter), and Huygens with Cassini (maybe various instrument packages on the surface of Mars too, communicating with us on Earth via equipment in orbit around Mars).

Various cameras aboard probes alive on the surface of Mars have been used to 'do astronomy' from the martian surface. While I doubt any have had the sensitivity to detect stellar (or any) aberration, they have certainly observed phenomena such as transits (e.g. Phobos across the Sun), the timing of which is consistent with a heliocentric model and a constant speed of light of c for such observers. Can Mr. Martin explain these results, using a geocentric model in which the Earth does not rotate?

Nereid

W.T."Tom" Bridgman said...

To Nereid,

In response to the above post, Mr. Martin essentially tried to spam the post with seven long comments that were largely rambling, repetitive, and denying the implications of how satellites operating around other planets behave essentially the same as they do around the 'center of the universe'.

A couple had some 'new' content that I'm holding for possible future release at an appropriate time.

Anonymous said...

Some other missions which have operated (or will operate) in orbit around a solar system object other than the Earth, and which involve(d) communication and/or science based on light (or radio) traveling between two points, neither of which is (on) the Earth:

* various Venera missions (landers communicated with the orbiters)

* Venus Pioneer 2 and Magellan (radar mapping, the radio equivalent of laser altitude ranging; Magellan's involved SAR - synthetic aperture radar - an especially challenging feat for geocentric models!)

* GRAIL, Gravity Recovery and Interior Laboratory (mapping the Moon's gravity field with a pair of satellites whose separation is determined by mutual 'ranging'; based on the same principles as the successful GRACE mission)

* NLR, the laser rangefinder which operated on NEAR (Near Earth Asteroid Rendezvous).

I note that all these experiments, and the laser altimetry ones referenced in the blog entry, differ from the APOLLO LLR one, in that the beam is returned by carefully crafted retro-reflectors in APOLLO.

However, the challenge for Mr Martin is to explain - quantitatively - how all this stuff works in his geocentric, non-rotating Earth, no-such-thing-as-relativity model. I do not doubt that hand-waving explanations are possible; what is required is, of course, a quantitative explanation.

Nereid

Anonymous said...

More on 'astronomy done on other worlds'.

In addition to the cameras on instrument packages on Mars' surface doing astronomy, there's astronomy done by the likes of Galileo and Cassini, while in orbit around Jupiter and Saturn, respectively.

The stellar occultations which Cassini observed - of Saturn's rings and Titan (perhaps more too) - should provide good tests of Mr Martin's geocentric model, especially the timing. After all, both Cassini and Titan are in (well-defined and well-characterised) orbits around Saturn (in Mr Martin's model), at rather precisely known distances from the Earth, and the clock aboard Cassini quite accurate.

Nereid

Michael Calza said...

Could you explain why you compared laser altimeters to retroreflectors? I've read John martin's response to this, and I have no real clue what the initial geocentrist argument even is when using the LLR. However, in his response, he claimed that since MOLA and LOLA do not use retro reflectors, which they don't, that makes your argument moot. Could you please clear up this confusion in any way? Thank you.

W.T."Tom" Bridgman said...

To Michael,

The mechanism being compared is a ranging experiment - same as radar. You send out a signal with a known speed. It strikes a distant object and some (or part) of the signal is reflected back towards the emitter, where it is recieved. The distance to the target is usually (there may be corrections due to relative motion, etc) about half of the total signal travel distance.

The only difference between a laser altimeter and a system such as LRR using a retroflector is the nature of the target.

The laser altimeter has a beam strike the surface of a planet and is not perfectly reflected back. The surface may absorb or scatter a significant portion of the beam intensity, reducing the intensity of the component reflected back towards the emitter or satellite.

A retroflector improves this situation by reflecting much more of the incoming signal back to the direction it came. There are complications due to aberration - due to the relative motions of the emitter, target, and receiver. However, because the beam is always diverging (getting wider with distance - even laser beams are not perfectly parallel), the receiver can still fall in the area covered by the returning beam.

Does that help?
Tom

Michael Calza said...

Hmm. Makes sense, seeing as both devices are sending out beams of light and get, shall we say "diluted" return trajectories. Directly quoting the article in question. " Tom - The LRR is not the only laser ranging experiment. I can think of three that have operated, or are operating, around the solar system:

MOLA was in orbit around Mars,
LOLA is currently in lunar orbit,
Messenger is at Mercury


JM – Tom fails to tell us that none of these experiments use retro-reflectors and as such, the lasers that bounce from a body, back to the satellite are not the same configuration at that used in the LLR. Therefore the LLR is a unique experiment that clearly indicates the moon is moving past a stationary earth.

Tom - (see Planetary Laser Altimetry). All these instruments operate by bouncing laser signals off the surface of the planet. All operate around the particular planet they orbit as if that planet were the center of the universe, or even as if the instrument itself were the center of the universe. The lasers use the exact same value of 'c' in computing their range from timing even though they are in motion relative to the Earth. This is as expected from relativity.

JM – Tom doesn’t give us any evidence for his claim that “the instrument itself were the center of the universe”, so why would anyone take his claim seriously, especially when we note the MOLA and other similar experiments don’t use retro reflectors? Does Tom really think everyone will miss this important and somewhat obvious point? Maybe he does.

Tom - If the Earth were truly a distinguished coordinate system as Mr. Martin claims, then you would expect these laser altimeters to operate differently when orbiting another planet.
JM – Laser altimeters only measure the distance between the satellite and the ground surface below the satellite. What is it about laser altimeters that requires the earth to be any different to other objects? Tom merely assumes so and then poses a false challenge to geocentrists to come up with the evidence that is not required.

Tom - Mr. Martin evades specifying what would be different in their operation. The simple fact is the laser altimeters operate exactly like they do when based the Earth, or Earth orbit, as predicted/expected by relativity.
JM – Mr Martin never discussed laser altimeters, so Mr Martin was not evading any issue at all. Tom is lying again.

Tom - This is not an idle question.
JM – taken in context of what the laser altimeter does, it is a dull and irrelevant question."

I do detect a few logical inconsistencies, however, I have one more question if you wouldn't mind answering it for me one last time. Do you feel ol' egocentric John here has any credence or sound basis for what he says here, why or why not? I'm just curious as to your answer, in studying geocentrist claims, I've actually been learning alot more about relativity than I ever have :)

W.T."Tom" Bridgman said...

Mike,

Sorry for the delay. I've been taking some time away to work on other projects.

Mr. Martin's claims are useless junk. We've been navigating satellites in space for over 50 years now using a knowledge base available in any physics text, much of which has been known for 300 years. All of that knowledge base is contrary to Mr. Martin's claims.

Laser altimeters & retro-reflectors determine distances, with the only difference being the nature of the reflection at the target. Light travel paths are identical, yet even this simple concept was beyond Mr. Martin's comprehension.

If you tried to implement Mr. Martin's interpretation into mathematics sufficient for satellite navigation (a task which I have repeatedly challenged the geocentrists to do, with no response!), if you're lucky, you'd just loose millions (billions?) of dollars in satellite and spacecraft assets. Hopefully one would stop before they actually got astronauts killed trying to implement this. If Mr. Martin were promoting this back in the late 1950s, he might have been suspected of trying to undermine the U.S. space program, maybe even of being a Soviet agent.

So how much 'credence or sound basis' could Mr. Martin's claims have?