Op 05-jun.-2022 om 18:39 schreef Al Coe:
> On Sunday, June 5, 2022 at 9:04:45 AM UTC-7, det...@outlook.com wrote:
>> Sorry, but I don't have time to do the calculations... Now I see you are asking me
>> to calculate the angles...
>
> Not at all. It doesn't take any "calculations" of angles, etc. Anyone who understands radar speed guns at all can answer that question instantly, because the distance between the cars is obviously increasing at a rate of 50 miles per hour. I thought you were an expert on this subject, and yet you can't correctly answer even the simplest question. What gives?
>
>> I've got better things to do. And I should have just ignored you question.
>
> If you want to be regarded as an expert on how radar speed guns work, shouldn't you be willing and able to answer (correctly) simple questions about the subject?
>
>> Time dilation has no measurable effect on how a radar gun works...
>> ...involves the speed of light PER SECOND, c, then the "atomic properties"
>> will be DIFFERENT when the LENGTH OF A SECOND is different due to a difference
>> in speed or gravity.
>
> Wait. First you say time dilation has no measurable effect on radar speed guns (basically true), but then in the very next sentence you say when things are measured at different speeds (or different gravity) the "length of the second" is
> different... which is time dilation. What gives? Is time dilation relevant, or is it not?
>
> If you want to be regarded as an expert on special relativity, shouldn't you be willing and able to answer (correctly) simple questions about the subject?

You make a mistake there, typical for this forum.
Ed does not want to be regarded as an exert on relativity
and on how radar speed guns work.
Ed wants to be regarded as an expert on making people spend
time and effort trying to educate the most stupid people on
the planet.

Dirk Vdm

On Sunday, June 5, 2022 at 10:52:46 AM UTC-7, Dirk Van de moortel wrote:
> > If you want to be regarded as an expert on special relativity, shouldn't you be willing and able to answer (correctly) simple questions about the subject?
>
> Ed does not want to be regarded as an expert on relativity and on
> how radar speed guns work.

I believe that he does.

> Ed wants to be regarded as an expert on making people spend
> time and effort trying to educate the most stupid people on
> the planet.

I don't think he wants to be regarded as "one of the most stupid persons on the planet". He wants to be regarded as an expert on (among other things) special relativity and on how radar speed guns work. My point (to him) is that he can't reasonably expect to be regarded as an expert on these things if his answers to even the simplest questions are blatantly wrong, nor even if he adopts the strategy of refusing to answer questions.

Op 05-jun.-2022 om 20:30 schreef Al Coe:
> On Sunday, June 5, 2022 at 10:52:46 AM UTC-7, Dirk Van de moortel wrote:
>>> If you want to be regarded as an expert on special relativity, shouldn't you be willing and able to answer (correctly) simple questions about the subject?
>>
>> Ed does not want to be regarded as an expert on relativity and on
>> how radar speed guns work.
>
> I believe that he does.
>
>> Ed wants to be regarded as an expert on making people spend
>> time and effort trying to educate the most stupid people on
>> the planet.
>
> I don't think he wants to be regarded as "one of the most stupid persons on the planet". He wants to be regarded as an expert on (among other things) special relativity and on how radar speed guns work. My point (to him) is that he can't reasonably expect to be regarded as an expert on these things if his answers to even the simplest questions are blatantly wrong, nor even if he adopts the strategy of refusing to answer questions.

You don't have to explain your point. It is very clear :-)

Dirk Vdm

Tom Roberts <tjroberts137@sbcglobal.net> wrote:

> On 6/3/22 11:59 AM, Ed Lake wrote:
> > According to Relativity, time ticks at a given rate on the surface of the
> > earth.
>
> Hmmm. You did not mention that relativity also implies that time ticks
> at EXACTLY THAT SAME RATE everywhere else in the universe, when measured
> in locally-inertial frames. This, of course, destroys your claims.
>
> > [...] Atoms in a MOVING object will have slightly different properties.
>
> No, they don't. Atomic properties, measured in their locally-inertial
> rest frames, are the same throughout the universe. We know this because
> of the tremendous success modern theoretical physics has in modeling the
> myriad observations and measurements of the cosmos.

Yes. In particular, we can measure spectra of atoms
from billions of years/lightyears, ago/away.
These spectra fully agree with what we measure here and now,
(apart from an overall red-shift)

These observations set tight limits
on the possible variation of \alpha, over time,
and hence on the variability of the laws of physics,

Jan

Ed Lake wrote:
>
> On Saturday, June 4, 2022 at 5:12:03 PM UTC-5, The Starmaker wrote:
> > Ed Lake wrote:
> > >
> > > On Saturday, June 4, 2022 at 3:59:47 PM UTC-5, The Starmaker wrote:
> > > > Ed Lake wrote:
> > > > >
> > > > > On Saturday, June 4, 2022 at 1:16:47 PM UTC-5, The Starmaker wrote:
> > > > > > Ed Lake wrote:
> > > > > >
> > > > > > > the fact that the universe around us is very likely INFINITE.
> > > > > > INFINITE???? How far is that?
> > > > >
> > > > > If you are unfamiliar with the word, look it up in a dictionary.
> > > > > You will see that your question displays MASSIVE ignorance.
> > > > >
> > > > > Ed
> > > > Well, you wrote in the same sentence the word..."fact". I didn't see any
> > > > indication that it is a fact.
> > >
> > > You need to learn to read more carefully. I didn't say it was a "fact."
> > > I said it is a fact that it is "VERY LIKELY INFINITE." Why is that a "fact"?
> > > Because if the universe wasn't infinite, we should be able to see the
> > > wall or whatever it is that surrounds everything. It would certainly be
> > > big enough. Then, of course, you have to wonder what is on the other
> > > side of that wall? Or is the wall infinite in depth?
> > >
> > > In sum, there is absolutely no reason to believe the universe is NOT
> > > infinite. PLUS, a finite universe seems illogical and impossible.
> > >
> > > Ed
> > "fact" means proved to be true.
>
> Okay.
>
> > It was never proven!
>
> No one said it was.
>
> > It's not a fact, Jack!
>
> No one said it was.
>
> > You shoulda wrote...very, very, very, very, very likely.
>
> It's very likely.
>
> > not even likely.
>
> It appears you just want to argue OPINIONS.
>
> > I don't accept people saying in science..."Well, it could be true."
>
> If there is no reason to believe it is false, and there is good reason to
> believe it is true, then it could be true.
>
> Which is more likely, that we live in an infinite universe or that we live
> in a finite universe? I'd say it is vastly more likely that we live in an INFINITE
> universe. And I find it just plain CRAZY that Quantum Mechanics mathematicians
> cannot cope with that.
>
> Ed

"Which is more likely..."???

You mean, which could be true?

How about if i flip a coin?

or play dice.

even Einstein sometimes plays your games when Einstein said "...God is malicious."

--
The Starmaker -- To question the unquestionable, ask the unaskable,
to think the unthinkable, mention the unmentionable, say the unsayable, and challenge
the unchallengeable.

On Sunday, 5 June 2022 at 21:41:29 UTC+2, J. J. Lodder wrote:
> Tom Roberts <tjrobe...@sbcglobal.net> wrote:
>
> > On 6/3/22 11:59 AM, Ed Lake wrote:
> > > According to Relativity, time ticks at a given rate on the surface of the
> > > earth.
> >
> > Hmmm. You did not mention that relativity also implies that time ticks
> > at EXACTLY THAT SAME RATE everywhere else in the universe, when measured
> > in locally-inertial frames. This, of course, destroys your claims.
> >
> > > [...] Atoms in a MOVING object will have slightly different properties.
> >
> > No, they don't. Atomic properties, measured in their locally-inertial
> > rest frames, are the same throughout the universe. We know this because
> > of the tremendous success modern theoretical physics has in modeling the
> > myriad observations and measurements of the cosmos.
> Yes. In particular, we can measure spectra of atoms
> from billions of years/lightyears, ago/away.
> These spectra fully agree with what we measure here and now,
> (apart from an overall red-shift)

Sure, they fully agree (apart from that they don't).

Paul Alsing wrote:
>
> On Saturday, June 4, 2022 at 11:16:47 AM UTC-7, The Starmaker wrote:
> > Ed Lake wrote:
> >
> > > the fact that the universe around us is very likely INFINITE.
> > INFINITE???? How far is that?
>
> Infinity is not a number...

numbers are not numbers...

if you take a 0,1,2,3,4,5,6-all the way to Infinity...you have an
infinite numbers that goes on to infinity.

but numbers are an invention of the mind and does not exist anywhere
else.

--
The Starmaker -- To question the unquestionable, ask the unaskable,
to think the unthinkable, mention the unmentionable, say the unsayable,
and challenge
the unchallengeable.

On Sunday, June 5, 2022 at 3:49:10 PM UTC-7, The Starmaker wrote:
> Paul Alsing wrote:
> >
> > On Saturday, June 4, 2022 at 11:16:47 AM UTC-7, The Starmaker wrote:
> > > Ed Lake wrote:
> > >
> > > > the fact that the universe around us is very likely INFINITE.
> > > INFINITE???? How far is that?
> >
> > Infinity is not a number...
>
> numbers are not numbers...

OK... so exactly what are numbers, if not numbers? Numbers are what we use to count things...
>
> if you take a 0,1,2,3,4,5,6-all the way to Infinity...you have an
> infinite numbers that goes on to infinity.

No, this is wrong. You cannot possibly count to infinity because infinity is not a number... if it were, then I could add a number to it... right? If you say that infinity *is* a number, well, what is that number? I will remind you also that there are an infinite number of numbers between 1 and 2... and between 2 and 3... and on and on to infinity...
> but numbers are an invention of the mind and does not exist anywhere
> else.

Yes, and they were invented so we could count things...

Paul Alsing wrote:
>
> On Sunday, June 5, 2022 at 3:49:10 PM UTC-7, The Starmaker wrote:
> > Paul Alsing wrote:
> > >
> > > On Saturday, June 4, 2022 at 11:16:47 AM UTC-7, The Starmaker wrote:
> > > > Ed Lake wrote:
> > > >
> > > > > the fact that the universe around us is very likely INFINITE.
> > > > INFINITE???? How far is that?
> > >
> > > Infinity is not a number...
> >
> > numbers are not numbers...
>
> OK... so exactly what are numbers, if not numbers? Numbers are what we use to count things...
> >
> > if you take a 0,1,2,3,4,5,6-all the way to Infinity...you have an
> > infinite numbers that goes on to infinity.
>
> No, this is wrong. You cannot possibly count to infinity because infinity is not a number... if it were, then I could add a number to it... right? If you say that infinity *is* a number, well, what is that number? I will remind you also that there are an infinite number of numbers between 1 and 2... and between 2 and 3... and on and on to infinity...
>
> > but numbers are an invention of the mind and does not exist anywhere
> > else.
>
> Yes, and they were invented so we could count things...

maybe i'm reading the definition wrong...

Mathematical infinities occur, for instance, as the number of points on a continuous line or as the size of the endless sequence of counting numbers: 1, 2, 3,….
https://www.britannica.com/science/infinity-mathematics

--
The Starmaker -- To question the unquestionable, ask the unaskable,
to think the unthinkable, mention the unmentionable, say the unsayable, and challenge
the unchallengeable.

On Sunday, June 5, 2022 at 11:06:39 PM UTC-7, The Starmaker wrote:
> Paul Alsing wrote:
> >
> > On Sunday, June 5, 2022 at 3:49:10 PM UTC-7, The Starmaker wrote:
> > > Paul Alsing wrote:
> > > >
> > > > On Saturday, June 4, 2022 at 11:16:47 AM UTC-7, The Starmaker wrote:
> > > > > Ed Lake wrote:
> > > > >
> > > > > > the fact that the universe around us is very likely INFINITE.
> > > > > INFINITE???? How far is that?
> > > >
> > > > Infinity is not a number...
> > >
> > > numbers are not numbers...
> >
> > OK... so exactly what are numbers, if not numbers? Numbers are what we use to count things...
> > >
> > > if you take a 0,1,2,3,4,5,6-all the way to Infinity...you have an
> > > infinite numbers that goes on to infinity.
> >
> > No, this is wrong. You cannot possibly count to infinity because infinity is not a number... if it were, then I could add a number to it... right? If you say that infinity *is* a number, well, what is that number? I will remind you also that there are an infinite number of numbers between 1 and 2... and between 2 and 3... and on and on to infinity...
> >
> > > but numbers are an invention of the mind and does not exist anywhere
> > > else.
> >
> > Yes, and they were invented so we could count things...
> maybe i'm reading the definition wrong...
>
>
> Mathematical infinities occur, for instance, as the number of points on a continuous line or as the size of the endless sequence of counting numbers: 1, 2, 3,….
> https://www.britannica.com/science/infinity-mathematics

A pity that you apparently did not read the entire article... you would learn that not all infinities are equal, and lots of other things that would make you think...

On Monday, June 6, 2022 at 1:55:44 PM UTC-7, Paul Alsing wrote:
> On Sunday, June 5, 2022 at 11:06:39 PM UTC-7, The Starmaker wrote:
> > Paul Alsing wrote:
> > >
> > > On Sunday, June 5, 2022 at 3:49:10 PM UTC-7, The Starmaker wrote:
> > > > Paul Alsing wrote:
> > > > >
> > > > > On Saturday, June 4, 2022 at 11:16:47 AM UTC-7, The Starmaker wrote:
> > > > > > Ed Lake wrote:
> > > > > >
> > > > > > > the fact that the universe around us is very likely INFINITE.
> > > > > > INFINITE???? How far is that?
> > > > >
> > > > > Infinity is not a number...
> > > >
> > > > numbers are not numbers...

Numbers are names.
> > >
> > > OK... so exactly what are numbers, if not numbers? Numbers are what we use to count things...
> > > >
> > > > if you take a 0,1,2,3,4,5,6-all the way to Infinity...you have an
> > > > infinite numbers that goes on to infinity.

If you take all finites unlimited you get the infinite.

> > >
> > > No, this is wrong. You cannot possibly count to infinity because infinity is not a number... if it were, then I could add a number to it... right? If you say that infinity *is* a number, well, what is that number? I will remind you also that there are an infinite number of numbers between 1 and 2... and between 2 and 3... and on and on to infinity...
> > >
> > > > but numbers are an invention of the mind and does not exist anywhere
> > > > else.

Numbers are the names of the eternal quantities.
Beyond the mind quantities are measurements of the physical.

> > >
> > > Yes, and they were invented so we could count things...
> > maybe i'm reading the definition wrong...
> >
> >
> > Mathematical infinities occur, for instance, as the number of points on a continuous line or as the size of the endless sequence of counting numbers: 1, 2, 3,….
> > https://www.britannica.com/science/infinity-mathematics
> A pity that you apparently did not read the entire article... you would learn that not all infinities are equal, and lots of other things that would make you think...

You need to read more you nut.
You are where you belong.

Mitchell Raemsch

On 5/28/2022 12:30 PM, Maciej Wozniak wrote:
> On Saturday, 28 May 2022 at 18:12:57 UTC+2, Paparios wrote:
>
>> The moving clock has been built identical to the at rest clock (they are both the same design). Speed can't affect the physics the clock uses to tick at 1 tick per second. For example a GPS atomic clock is set to tick at 10.22999999543 MHz before launching. When the GPS clock is orbiting (at a hight of 22000 km) the GPS atomic clock is still ticking at 10.22999999543 MHz
>
>
> No it is not. It is 10.23, both measured HERE and measured THERE.

But he wrote the clock was set to 10.22999999543 MHz before launch. Explain?

On Wednesday, 8 June 2022 at 01:19:20 UTC+2, Volney wrote:
> On 5/28/2022 12:30 PM, Maciej Wozniak wrote:
> > On Saturday, 28 May 2022 at 18:12:57 UTC+2, Paparios wrote:
> >
> >> The moving clock has been built identical to the at rest clock (they are both the same design). Speed can't affect the physics the clock uses to tick at 1 tick per second. For example a GPS atomic clock is set to tick at 10.22999999543 MHz before launching. When the GPS clock is orbiting (at a hight of 22000 km) the GPS atomic clock is still ticking at 10.22999999543 MHz
> >
> >
> > No it is not. It is 10.23, both measured HERE and measured THERE.
>
> But he wrote the clock was set to 10.22999999543 MHz before launch. Explain?

If you set a pendulum to 0,166s on Earth and then take it on
Moon - it will wave ~1s. Do you get it? Things are similiar
with 10.22999999543 MHz Cs clock taken to a GPS satellite.
We can measure it with the clocks THERE (as everybody knows,
they're set to ~9 192 631 774) and we'll get 10.23.

On 6/8/2022 1:49 AM, Maciej Wozniak wrote:
> On Wednesday, 8 June 2022 at 01:19:20 UTC+2, Volney wrote:
>> On 5/28/2022 12:30 PM, Maciej Wozniak wrote:
>>> On Saturday, 28 May 2022 at 18:12:57 UTC+2, Paparios wrote:
>>>
>>>> The moving clock has been built identical to the at rest clock (they are both the same design). Speed can't affect the physics the clock uses to tick at 1 tick per second. For example a GPS atomic clock is set to tick at 10.22999999543 MHz before launching. When the GPS clock is orbiting (at a hight of 22000 km) the GPS atomic clock is still ticking at 10.22999999543 MHz
>>>
>>>
>>> No it is not. It is 10.23, both measured HERE and measured THERE.
>>
>> But he wrote the clock was set to 10.22999999543 MHz before launch. Explain?
>
> If you set a pendulum to 0,166s on Earth and then take it on
> Moon - it will wave ~1s. Do you get it?

Not applicable. A Cs clock is not a pendulum clock whose period depends
on a nearby mass (which is essentially part of the clock).

Why does a clock set to 10.22999999543 MHz before launch become 10.23
MHz in orbit? And why do Einstein's equations just happen to get it right?

On June 5, Al Coe wrote:
>>> Two vehicles pass each other at an intersection, one
>>> going North at 40 mph and the other going east at 30 mph.
>>> Some time later (they can still see each other), they each check
>>> the others' speed using a simple speed gun. What speeds do the guns show?
>
> No, each speed gun reads 50 mph in this case. Remember, when applying the cosine effect,
> the relevant angle is *not* the angle between the velocity vectors of the gun and target in terms
> of some arbitrary reference system, it is the angle between the direction of the radar beam and the
> direction of the target in terms of the rest frame of the gun. In this example, that angle is zero,
> A simpler way of answering the question is to remember that a simple radar speed gun always
> shows the rate of change of the distance between gun and target.

For a more interesting example, imagine this scenario takes place in
a universe where c = 100 mph. What does the radar gun read, then?
How should the observer operate it, to obtain an accurate reading?

--
Rich

On June 8, Volney wrote:
> A Cs clock is not a pendulum clock whose period depends
> on a nearby mass (which is essentially part of the clock).

The period of a Cs clock doesn't depend on a nearby mass.
OK
> Why does a clock set to 10.22999999543 MHz before launch become 10.23
> MHz in orbit?

Because its period is influenced by a nearby mass?

--
Rich

On Wednesday, 8 June 2022 at 17:36:04 UTC+2, Volney wrote:
> On 6/8/2022 1:49 AM, Maciej Wozniak wrote:
> > On Wednesday, 8 June 2022 at 01:19:20 UTC+2, Volney wrote:
> >> On 5/28/2022 12:30 PM, Maciej Wozniak wrote:
> >>> On Saturday, 28 May 2022 at 18:12:57 UTC+2, Paparios wrote:
> >>>
> >>>> The moving clock has been built identical to the at rest clock (they are both the same design). Speed can't affect the physics the clock uses to tick at 1 tick per second. For example a GPS atomic clock is set to tick at 10.22999999543 MHz before launching. When the GPS clock is orbiting (at a hight of 22000 km) the GPS atomic clock is still ticking at 10.22999999543 MHz
> >>>
> >>>
> >>> No it is not. It is 10.23, both measured HERE and measured THERE.
> >>
> >> But he wrote the clock was set to 10.22999999543 MHz before launch. Explain?
> >
> > If you set a pendulum to 0,166s on Earth and then take it on
> > Moon - it will wave ~1s. Do you get it?
> Not applicable.

An uninformed opinion of a stupid Mike doesn't count.

> Why does a clock set to 10.22999999543 MHz before launch become 10.23
> MHz in orbit? And why do Einstein's equations just happen to get it right?

They don't. They keep insisting it stays 10.22999999543,
against facts.

On Wednesday, June 8, 2022 at 1:22:19 PM UTC-7, RichD wrote:
> On June 5, Al Coe wrote:
> >>> Two vehicles pass each other at an intersection, one
> >>> going North at 40 mph and the other going east at 30 mph.
> >>> Some time later (they can still see each other), they each check
> >>> the others' speed using a simple speed gun. What speeds do the guns show?
> >
> > No, each speed gun reads 50 mph in this case. Remember, when applying the cosine effect,
> > the relevant angle is *not* the angle between the velocity vectors of the gun and target in terms
> > of some arbitrary reference system, it is the angle between the direction of the radar beam and the
> > direction of the target in terms of the rest frame of the gun. In this example, that angle is zero,
> > A simpler way of answering the question is to remember that a simple radar speed gun always
> > shows the rate of change of the distance between gun and target.
> For a more interesting example, imagine this scenario takes place in
> a universe where c = 100 mph. What does the radar gun read, then?
> How should the observer operate it, to obtain an accurate reading?

Counterfactual hypotheticals about alternate universes are inevitably ambiguous, e.g., if a hypothetical universe has c=100 mph, would all the dimensionless ratios be the same? If so, then it would just be a re-definition of units with no physical significance, but if not, then the universe would be fundamentally different in ways that totally swamp the question.

However, I agree that it would have been instructive for Ed to consider a case in our universe, with the cars replaced by spaceships moving at 0.3c and 0.4c. Then he could be taught that the radar speed guns would not read 0..5c, but would actually read 0.4853c, which would help to begin teaching him about actual relativistic effects... which aren't significant for ordinary car speeds.

RichD <r_delaney2001@yahoo.com> wrote:

> On June 5, Al Coe wrote:
> >>> Two vehicles pass each other at an intersection, one
> >>> going North at 40 mph and the other going east at 30 mph.
> >>> Some time later (they can still see each other), they each check
> >>> the others' speed using a simple speed gun. What speeds do the guns show?
> >
> > No, each speed gun reads 50 mph in this case. Remember, when applying
> > the cosine effect, the relevant angle is *not* the angle between the
> > velocity vectors of the gun and target in terms of some arbitrary
> > reference system, it is the angle between the direction of the radar
> > beam and the direction of the target in terms of the rest frame of the
> > gun. In this example, that angle is zero, A simpler way of answering the
> > question is to remember that a simple radar speed gun always shows the
> > rate of change of the distance between gun and target.
>
> For a more interesting example, imagine this scenario takes place in
> a universe where c = 100 mph. What does the radar gun read, then?
> How should the observer operate it, to obtain an accurate reading?

Or do better, and read Gamow's Mr. Tompkins in Wonderland,
(forgotten, but c = 25 km/h or something like that)

Jan

FYA, Mr. Tompkins sees a cyclist working very hard at getting faster.
He asks: Why do you bother, you do know you can't go any faster?
The cyclist says, yes I know, but if I pedal harder
the city blocks get so much shorter,
so I cover more distance in the same time.

On Thursday, 9 June 2022 at 14:36:39 UTC+2, J. J. Lodder wrote:
> RichD <r_dela...@yahoo.com> wrote:
>
> > On June 5, Al Coe wrote:
> > >>> Two vehicles pass each other at an intersection, one
> > >>> going North at 40 mph and the other going east at 30 mph.
> > >>> Some time later (they can still see each other), they each check
> > >>> the others' speed using a simple speed gun. What speeds do the guns show?
> > >
> > > No, each speed gun reads 50 mph in this case. Remember, when applying
> > > the cosine effect, the relevant angle is *not* the angle between the
> > > velocity vectors of the gun and target in terms of some arbitrary
> > > reference system, it is the angle between the direction of the radar
> > > beam and the direction of the target in terms of the rest frame of the
> > > gun. In this example, that angle is zero, A simpler way of answering the
> > > question is to remember that a simple radar speed gun always shows the
> > > rate of change of the distance between gun and target.
> >
> > For a more interesting example, imagine this scenario takes place in
> > a universe where c = 100 mph. What does the radar gun read, then?
> > How should the observer operate it, to obtain an accurate reading?
> Or do better, and read Gamow's Mr. Tompkins in Wonderland,
> (forgotten, but c = 25 km/h or something like that)
>
> Jan
>
> FYA, Mr. Tompkins sees a cyclist working very hard at getting faster.
> He asks: Why do you bother, you do know you can't go any faster?
> The cyclist says, yes I know, but if I pedal harder
> the city blocks get so much shorter,
> so I cover more distance in the same time.

Yet another fabricated delusion proving Giant Guru correct;
in the meantime in the real world, however, forbidden by
your insane religion GPS and TAI keep measuring t'=t, just
like all serious clocks always did.

On 6/8/2022 11:39 PM, RichD wrote:
> On June 8, Volney wrote:
>> A Cs clock is not a pendulum clock whose period depends
>> on a nearby mass (which is essentially part of the clock).
>
> The period of a Cs clock doesn't depend on a nearby mass.
> OK
>
>> Why does a clock set to 10.22999999543 MHz before launch become 10.23
>> MHz in orbit?
>
> Because its period is influenced by a nearby mass?

It is, which is the whole point, but try to get the janitor to
understand that. It's influenced by the nearby mass exactly as Einstein
predicted. And trying to compare it to a pendulum clock which has a
period directly proportional to the local gravitational acceleration,
vs. the GPS and a few hundred parts per trillion on the potential is
absurd. But he tries to be misleading...

On June 9, J. J. Lodder wrote:
>> >>> Two vehicles pass each other at an intersection, one
>> >>> going North at 40 mph and the other going east at 30 mph.
>> >>> Some time later (they can still see each other), they each check
>> >>> the others' speed using a simple speed gun. What speeds do the guns show?
>> > each speed gun reads 50 mph in this case.
>
>> For a more interesting example, imagine this scenario takes place in
>> a universe where c = 100 mph. What does the radar gun read, then?
>> How should the observer operate it, to obtain an accurate reading?
>
> Or do better, and read Gamow's Mr. Tompkins in Wonderland,
> Mr. Tompkins sees a cyclist working very hard at getting faster.
> He asks: Why do you bother, you do know you can't go any faster?
> The cyclist says, yes I know, but if I pedal harder
> the city blocks get so much shorter,
> so I cover more distance in the same time.

What would a tennis match be like, at relativistic speed?

--
Rich

On June 8, Al Coe wrote:
>> >>> Two vehicles pass each other at an intersection, one
>> >>> going North at 40 mph and the other going east at 30 mph.
>> >>> Some time later, they each check the others' speed using a
>> >>> simple speed gun. What speeds do the guns show?
>>> each speed gun reads 50 mph in this case.
>>> Remember, when applying the cosine effect, the relevant angle is
>>> *not* the angle between the velocity vectors of the gun and target in terms
>>> of some arbitrary reference system, it is the angle between the direction of
>>> the radar beam and the direction of the target in terms of the rest frame
>>> of the gun. In this example, that angle is zero,
>>> A simpler way of answering the question is to remember that a simple
>>> radar speed gun always shows the rate of change of the distance between
>>> gun and target.
>
>> For a more interesting example, imagine this scenario takes place in
>> a universe where c = 100 mph. What does the radar gun read, then?
>> How should the observer operate it, to obtain an accurate reading?
>
> Counterfactual hypotheticals about alternate universes are inevitably ambiguous,
> e.g., if a hypothetical universe has c=100 mph, would all the dimensionless ratios
> be the same? If so, then it would just be a re-definition of units with no physical
> significance, but if not, then the universe would be fundamentally different in
> ways that totally swamp the question.

Just a change in the Lorentz constant, nothing else.
What else would be affected, regarding this simple example?

> However, I agree that it would have been instructive for Ed to consider a case
> in our universe, with the cars replaced by spaceships moving at 0.3c and 0.4c.
> Then he could be taught that the radar speed guns would not read 0.5c, but
> would actually read 0.4853c, which would help to begin teaching him about
> actual relativistic effects... which aren't significant for ordinary car speeds.

I had in mind the analogy of a quarterback leading a receiver,
crossing the field, also running down field.

How would the radar gun aim have to be modified,
if the vehicles travel at .5 c?

--
Rich

On Thursday, June 9, 2022 at 10:57:38 AM UTC-7, RichD wrote:
On June 8, Al Coe wrote:
> >> For a more interesting example, imagine this scenario takes place in
> >> a universe where c = 100 mph. What does the radar gun read, then?
> >> How should the observer operate it, to obtain an accurate reading?
> >
> > Counterfactual hypotheticals about alternate universes are inevitably ambiguous,
> > e.g., if a hypothetical universe has c=100 mph, would all the dimensionless ratios
> > be the same? If so, then it would just be a re-definition of units with no physical
> > significance, but if not, then the universe would be fundamentally different in
> > ways that totally swamp the question.
>
> Just a change in the Lorentz constant, nothing else.
> What else would be affected, regarding this simple example?

If you just change the numerical value of c in terms of some units, but don't change the other constants of nature, such as the fine structure constant, etc., then the resulting universe would typically not even be consistent with the existence of the ordinary laws of physics, formation of the elements, stars, and so on. The very existence of something even remotely resembling our universe places very tight constraints on the dimensionless ratios of the constants of nature. So, you need to specify that you are changing all the constants so that the dimensionless ratios are the same... but in that case you are just re-defining units, and there's no physical change.

> > However, I agree that it would have been instructive for Ed to consider a case
> > in our universe, with the cars replaced by spaceships moving at 0.3c and 0.4c.
> > Then he could be taught that the radar speed guns would not read 0.5c, but
> > would actually read 0.4853c, which would help to begin teaching him about
> > actual relativistic effects... which aren't significant for ordinary car speeds.
>
> I had in mind the analogy of a quarterback leading a receiver,
> crossing the field, also running down field. How would the radar
> gun aim have to be modified, if the vehicles travel at .5 c?

Not at all. In this example, in terms of the co-moving inertial coordinates of each gun, the other is moving directly away from it at the speed 0.4853c. Just point and shoot. The radar gun works fine.

If you wanted to consider some transverse motion with aberration, you should have started with the less trivial example I posed to Ed, in which the guns don't pass through the intersection at the same time. To warn up, work out the answer for realistic car speeds using Newtonian physics. Then go on to the case with relativistic speeds.

RichD <r_delaney2001@yahoo.com> wrote:

> On June 9, J. J. Lodder wrote:
> >> >>> Two vehicles pass each other at an intersection, one going North at
> >> >>> 40 mph and the other going east at 30 mph. Some time later (they
> >> >>> can still see each other), they each check the others' speed using
> >> >>> a simple speed gun. What speeds do the guns show?
> >> > each speed gun reads 50 mph in this case.
> >
> >> For a more interesting example, imagine this scenario takes place in
> >> a universe where c = 100 mph. What does the radar gun read, then?
> >> How should the observer operate it, to obtain an accurate reading?
> >
> > Or do better, and read Gamow's Mr. Tompkins in Wonderland,
> > Mr. Tompkins sees a cyclist working very hard at getting faster.
> > He asks: Why do you bother, you do know you can't go any faster?
> > The cyclist says, yes I know, but if I pedal harder
> > the city blocks get so much shorter,
> > so I cover more distance in the same time.
>
> What would a tennis match be like, at relativistic speed?

Killing,

Jan