Re: The Shapiro's experiment HOAX. A 1968 TIME article.

rhertz <hertz778@gmail.com> wrote:

On Sat, 19 Oct 2024 19:42:59 +0000, J. J. Lodder wrote:
 
<snip>
 

[snip irelevancies about history space travel, yes we all know]
>
And back to the point:
You whine about a popularised account of Shapiro's radar measurements
of planetary distances. (and relativistic delays that were a by-product)
All this from almost 60 years ago.
>
It has completely escaped your notice that in the meantime
measurements in the solar system have increased more than a thousandfold
in accuracy,
(by using transponders in interplanetary probes instead of radar echos)
and that Shapiro delays are nowadays taken into account
as a routine correction that needs to be applied
to get interplanetary distances and hence navigation right.
>
In other words, it is no longer an issue of science,
it is routine engineering, (at places like JPL)
>
Jan

 
I insist that you are an ignorant idiot pretending to know something
about radio/laser communications.
 
You are the one who started this by asserting that passive reflections
of EM radiation decay with 1/r?, and not the usual 1/r?. This stupidity
alone is enough to disqualify you for any further discussion about EM
propagation in outer space. Any RF/laser engineering expert would put
you on the "IGNORE LIST", just for being such a donkey.

I should have expressed myself more carefully there.
Meant was of course an extra factor 4 for twice the distance.

I have to remark a couple of things:
 
1. If you are a woman, I apologize. I only call names to men. Even more,
   I withdraw my comments about your stupidity and ignorance, and let
   you to chose what you are. Of course that you're not a connoisseur on
   these subjects.

My my, a Frenchie pretending to be a gentleman.
 

2. You didn't let me know which are your academical degrees. Let me
   know, as it would help a lot to understand some biases of your
   thoughts.

Three doctorates and two Nobel prizes, just like you.

3. You keep insisting with transponders and their importance, as if I
   had written anything about them. On the contrary, I showed to you
   that transponders are essential in space (and earthly) travels.

You were obviousy ignorant of the importance of them
in the context of precise space navigation.

4. It makes me sad your ignorance about what is required for space
   travel's guidance. It seems that you didn't read a single word of
   what I wrote on this matter.

I did, it is nonsense.

5. Shapiro's delay is IRRELEVANT in space travel. Completely useless.
   Any space flight is computed IN REAL TIME with many sophisticated
   optical and EM based techniques, like triangulations with WELL KNOWN
   trajectories of selected celestial bodies (planets, moons, asteroids)
   plus the traditional guidance by well known fixed stars.

Those 'sophisticated optical and EM based techniques'
do need relativistic corrections.
(at the present level of accuracy)

   There is no 3D celestial GPS to be used in space flights. A link
   with Earth stations are UNIDIMENSIONAL in a 3D space.

It is necessary to do a complete integration
involving the whole solar system to know where everything is.
(to a hundred meters or so, limited mainly by asteroid noise)
This is of course an expert job. (for JPL for example)
It requires a lot of computational power.

The accuracy has increased to the point where it becomes necessary
to give the AU a defined value, because the motions of the Earth are to
erratic to serve as a base for it.

Back to the point: Once you arrive at accuracies measured in nanoseconds
the Shapiro delay becomes a correction to be applied routinely,

Jan

--
1 astronomical unit         = 149 597 870 700 metres (exactly)
Best measurement before was = 149 597 870 691(6)
Yes, positions objects in the solar system are noways known
to a few meters, or some tens of nanoseconds.