GPS news

[AMuzi]

https://astronomy.com/news/2022/02/earth-is-spinning-faster-now-than-it-was-50-years-ago

You're not riding slower. The planet's spinning faster.
--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

[Jeff Liebermann]

On Tue, 02 Aug 2022 08:36:08 -0500, AMuzi <a...@yellowjersey.org> wrote:

>https://astronomy.com/news/2022/02/earth-is-spinning-faster-now-than-it-was-50-years-ago
>
>You're not riding slower. The planet's spinning faster.

Wrong. GPS and UTC time have been drifting apart since they were
"harmonized" in Jan 1980. Today, they're 18 seconds apart.
<http://leapsecond.com/java/gpsclock.htm>
<http://www.learnbydestroying.com/jeffl/crud/GPS-vs-UTC.jpg>
Your watch displays UTC time.

UTC time is adjusted for leap seconds. GPS time doesn't do leap
seconds.

When you time your ride by a clock, you're using UTC. So, how does
that work if your clock is a GPS bicycling computer? Easy. Your
computer just subtracts 18 seconds from the GPS time to display UTC
time. If you time how long it takes for you to ride 1 mile, your GPS
bicycling computer subtracts 18 seconds from both the start and finish
of your ride resulting in no change to your elapsed time.

However, that doesn't do much for the astronomers. For them, sidereal
time, or time relative to the stars, is what's important.
<https://en.wikipedia.org/wiki/Sidereal_time>
Unfortunately, the position of the stars are not constant. Also, the
earth like to wobble, making using the North Star as a reference point
rather marginal. So, solar time and sidereal time have been
disconnected:
<https://lco.global/spacebook/sky/sidereal-time/>
Astronomers have contrived various time systems to deal with their
problems. Some history:
<https://www.ucolick.org/~sla/leapsecs/timescales.html>
Notice the Microsoft Windoze 10 FILETIME switched from UTC to TAI
minus 37 seconds and added leap seconds support.

What does all this have to do with bicycle racing, riding and timing?
Nothing. I just thought it would be of some interest[1].

All races and timing involves relative time, not absolute time. All
that's needed is for the length of 1 second be standardized, which was
done in 1967 and is defined as 9,192,631,770 cycles of Cesium-133
emissions. That is a physical constant and does not depend on what
the earth or stars are doing in their spare time. The planet could
wander out of orbit, but your race scores would remain unchanged.

So, you're not riding slower and your race scores and speeding tickets
will remain unchanged, no matter how fast or slow the earth rotates.


[1] I can usually tell when I write something interesting. Nobody
replies or asks questions. Since I've seen few replies or question
about my recent GPS lectures in RBT, I'll assume that there are a few
interested parties in the audience.

--
Jeff Liebermann je...@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

[Frank Krygowski]

On 8/2/2022 9:36 AM, AMuzi wrote:
> https://astronomy.com/news/2022/02/earth-is-spinning-faster-now-than-it-was-50-years-ago
>
>
> You're not riding slower. The planet's spinning faster.

Ah! That explains why time seems to go by faster as I've gotten older!

--
- Frank Krygowski

[funkma...@hotmail.com]

I was convinced Andrews comment was tongue-in-cheek, which is why I didn't respond, but my first thought was "I don't think those are related".
Any ways, I _do_ read your technical explanations with great interest. You have the time to research a lot of interesting subjects that I don't. Unlike certain other willfully ignorant trolls in this forum, I fully appreciate that you provide rational explanations with cites and references.

[Jeff Liebermann]

Thanks. My footnote was also mostly tongue-in-cheek, but does
represent a serious observation. Trivial comments seem to attract the
most attention on Usenet and other forums. Serious and complete
answers are usually ignored.

Good to know someone appreciates my efforts. It requires quite a bit
of time to write my long replies and provide the necessary links and
substantiations. I've been answering questions and being facetious
since the beginnings of Usenet in about 1985 in much the same way. The
lengthy explanations and copious references are a reflection of what I
would like to be reading on Usenet. One line replies (SMS message
style) are probably more efficient, but without the associated detail,
offer little of interest.

I have the time to write now for an odd reason. About 2 weeks ago, I
was exposed to Covid and decided to self-isolate. That resulted in a
10 day vacation which I greatly enjoyed because I was able (in good
conscience) to chase away anyone who wanted me to do something for
them. I had such a good time of not being involved in everyone's
crisis of the day and doing what I thought interesting, that I
extended my vacation for an additional week (and possibly longer).
Reality will eventually catch up with me, but for now, loafing and
playing on the computah suits me quite nicely.

Thanks again.

[This reply took me about 20 minutes to write].

[Roger Merriman]

That’s the less stuff happening, the year of my accident and few years
after where very full with hospitals and what not, and thus time slowed.

Roger Merriman

[ritzann...@gmail.com]

I am going to go with the not related part. Analogy time. Riding in a car in the backseat. Or 4 door pickup truck which seems to be more common than cars now days. Car/truck going 50 mph or 60 mph or 70 mph. You in the backseat flipping a ball between your hands. Speed of vehicle does not affect speed of you tossing the ball back and forth. Therefore, how fast the earth is spinning or going around the sun does not affect what is happening on the earth itself.

[AMuzi]

You have an actual right-wing 'assault truck'? I've been
told the drivers are antisocial if not a menace.

[Jeff Liebermann]

On Tue, 2 Aug 2022 17:50:25 -0700 (PDT), "russell...@yahoo.com"
<ritzann...@gmail.com> wrote:

>I am going to go with the not related part. Analogy time. Riding in a car in the backseat. Or 4 door pickup truck which seems to be more common than cars now days. Car/truck going 50 mph or 60 mph or 70 mph. You in the backseat flipping a ball between your hands. Speed of vehicle does not affect speed of you tossing the ball back and forth. Therefore, how fast the earth is spinning or going around the sun does not affect what is happening on the earth itself.

I've been accused of hair splitting several time. This is probably a
good time to reinforce my reputation for hair splitting.

Replace the ball with an electronic clock and it too will not show a
noticeable change in timing. However, move the clock around at
relativistic speeds, and you will see time dilation in action. The
faster the clock moves, the slower it runs.
<https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment>

Incidentally, run the ball tossing experiment with a mechanical clock
and you'll have to deal with the same problems that John Harrison
eventually solved when he built a mechanical clock suitable for
measuring latitude.
<https://www.rmg.co.uk/stories/topics/harrisons-clocks-longitude-problem>

Liebermann's First Law of Motion:
"If it moves, it will be the first to fail".

[ritzann...@gmail.com]

??????? Not sure how politics or assault rifles got into the conversation about the earth spinning faster. But maybe with global warming it is heating the world up, and melting the polar ice caps, and therefore the earth is hotter and has more fuel and thus is spinning faster. Maybe spinning faster to help throw off the excess heat. I know faster air flow helps cool engines. It is possible and plausible that the right wing pick up trucks are burning more gasoline, or diesel, and therefore heating the earth up faster causing the earth to spin faster. And that all makes your bicycle rides slower, or maybe faster. Logical.

As for trucks, my family owns a pick up truck. Its a two door regular cab. Not four door. You can turn the wheels both right and left. Last time we used it was to haul a load of metal to the scrap yard. It gets 15 mph on the highway with the 5.8 liter V8. So unless you have to drive it, you don't really want to drive it. From an economical perspective. Its also rough riding and you bounce up and down in it. I'm guessing the four door city trucks are gentler riding and softer on the owner's behinds.

[ritzann...@gmail.com]

But would any of this affect how long it takes for you to toss the ball from one hand to the other hand? If it takes one second to toss the ball from the left to right hand, would that change depending on how fast the enclosing vehicle is moving? I'm not too worried about tossing clocks around. Balls are easier to catch. Clocks are not round and smooth and easy to catch.

[Frank Krygowski]

On Tuesday, August 2, 2022 at 9:00:58 PM UTC-4, AMuzi wrote:
> You have an actual right-wing 'assault truck'? I've been
> told the drivers are antisocial if not a menace.

Some pickup trucks are work vehicles chosen for practical reasons
and appropriate for their jobs.

Others are chosen by bullies to demonstrate petro-masculinity and
compensate for their weakness.

It's not hard to tell which are which. For one extreme example, if it's
blowing huge clouds of dense black smoke as it passes people, it's
the latter.

- Frank Krygowski

[John B.]

You sound like owning a pickup is sort of unique experience... yet I
read that the Ford pickup is the most sold motor vehicle in the U.S.
(:-)
--
Cheers,

John B.

[Jeff Liebermann]

On Tue, 2 Aug 2022 18:52:46 -0700 (PDT), "russell...@yahoo.com"

<ritzann...@gmail.com> wrote:

>On Tuesday, August 2, 2022 at 8:15:05 PM UTC-5, jeff.li...@gmail.com wrote:
>> On Tue, 2 Aug 2022 17:50:25 -0700 (PDT), "russell...@yahoo.com"
>> <ritzann...@gmail.com> wrote:
>>
>> >I am going to go with the not related part. Analogy time. Riding in a car in the backseat. Or 4 door pickup truck which seems to be more common than cars now days. Car/truck going 50 mph or 60 mph or 70 mph. You in the backseat flipping a ball between your hands. Speed of vehicle does not affect speed of you tossing the ball back and forth. Therefore, how fast the earth is spinning or going around the sun does not affect what is happening on the earth itself.
>> I've been accused of hair splitting several time. This is probably a
>> good time to reinforce my reputation for hair splitting.
>>
>> Replace the ball with an electronic clock and it too will not show a
>> noticeable change in timing. However, move the clock around at
>> relativistic speeds, and you will see time dilation in action. The
>> faster the clock moves, the slower it runs.
>> <https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment>
>>
>> Incidentally, run the ball tossing experiment with a mechanical clock
>> and you'll have to deal with the same problems that John Harrison
>> eventually solved when he built a mechanical clock suitable for
>> measuring latitude.
>> <https://www.rmg.co.uk/stories/topics/harrisons-clocks-longitude-problem>
>>
>> Liebermann's First Law of Motion:
>> "If it moves, it will be the first to fail".

>But would any of this affect how long it takes for you to toss the ball from one hand to the other hand?
>If it takes one second to toss the ball from the left to right hand, would that change depending on how fast the enclosing vehicle is moving?

No. Below velocities where relativity starts making things slower and
heavier, you won't see anything different. Newton's 3 laws continue
to work as advertised.

However, GPS satellites fly at 3.9 km/sec. The speed of light is
300,000 km/sec. Therefore, the GPS satellites fly at:
3.9 / 300,000 = 0.0013% of the speed of light
That would seem to be a trivially small percentage, hardly worth
considering, except for one big problem. The accuracy required for
GPS to function requires compensation for time dilation (and other
errors) well beyond such "small" errors. Without compensating for
relativistic effects, GPS simply wouldn't work:

<https://physicscentral.com/explore/writers/will.cfm>
"... the orbiting clocks are 20,000 km above the Earth, and experience
gravity that is four times weaker than that on the ground. Einstein's
general relativity theory says that gravity curves space and time,
resulting in a tendency for the orbiting clocks to tick slightly
faster, by about 45 microseconds per day. The net result is that time
on a GPS satellite clock advances faster than a clock on the ground by
about 38 microseconds per day. But at 38 microseconds per day, the
relativistic offset in the rates of the satellite clocks is so large
that, if left uncompensated, it would cause navigational errors that
accumulate faster than 10 km per day!"

So, if your navigation system is based on tossing a ball back and
forth (also known as a pendulum), you would ride off the edge of the
(flat) earth and fall into the abyss.

>I'm not too worried about tossing clocks around. Balls are easier to catch. Clocks are not round and smooth and easy to catch.

What about clocks in the shape of a ball?
<https://www.google.com/search?q=sphere+clock&tbm=isch>
I like this one:
<https://www.istockphoto.com/photo/abstract-wall-clock-in-form-of-sphere-gm488369109-39183272>

[ritzann...@gmail.com]

Yes. But my Ford is a regular cab. Rarely ever see those today. Everything seems to be extended cab or four door trucks today. Rarely see 8 foot full length beds either. Shorter 5-6 foot beds are common today.

As for most sold vehicle, yes, and the Chevy pickup is probably the second most sold. And Dodge pickup might be the third most sold. But with pickups I have a hard time lumping them all together. You have half ton, three quarter ton, one ton. All grouped together. Then you have 8 foot, 6.5 foot, 5 foot beds. All lumped together. Then 4 cylinder, 6 cylinder, 8 cylinder engines. And electric now too. All lumped together. 2 wheel drive and 4 wheel drive. All lumped together. 2 door, extended cab, 4 door. And GM has a shorter 4 door in addition to the regular 4 door. Everything grouped together. Does it really make sense to group everything together and say its just one vehicle sales? All of what I just wrote is different than the usual luxury levels of XL, XLT, Super XLT+. Or however the different levels are classified now days. Cars come in basic manual no power no air models and then in automatic heated seat air conditioner models. But same car. Pickup trucks are different from that.

[John B.]

On Wed, 3 Aug 2022 00:02:06 -0700 (PDT), "russell...@yahoo.com"

I can't even guess what y'all are doing "back there" but here any
truck is considered a working vehicle and thus is subject to lower
taxes then a "sedan". so a great many people buy pickups :-) And,
while 4 door pickups are not rare - my wife's younger sister has one
for her business - if you go to the supermarket parking lot the 2 door
version is obviously the more popular version. Available with all "mod
cons", air con, radio, automatic, and so on. (no heaters though :-(
--
Cheers,

John B.

[funkma...@hotmail.com]

The state of new hampshire bases its annual vehicle tax on the gross vehicle weight. The owner of a new Mercedes SL6 will pay less tax than the owner of a ten-year-old F-150. You still see far more pick-ups and large SUVs than even moderately priced sedans in new hampshire . Most of them rarely leave the pavement and do little more "work" than fetching groceries, and a significant number of those sport trump stickers with have license plates with such friendly messages as "LBRLHNTR".

Oh, and they are the least tolerant of cyclists as well.

[John B.]

What is "gross weight" for registration purposes? Total vehicle weight
plus designed maximum load. i.e., 1 ton pickup is total weight of
vehicle plus 1 ton?

But in one sense that seems logical as roads are, I believe, designed
for a maximum wheel loading.

>Oh, and they are the least tolerant of cyclists as well.

Over here the law says that slower vehicles will keep to the left side
of the road which in practice seems to be bicycles, small motorcycles
and heavy trucks and we don't seem to have many problems of that sort.
--
Cheers,

John B.

[funkma...@hotmail.com]

Yes, vehicle weight plus maximum load

>
> But in one sense that seems logical as roads are, I believe, designed
> for a maximum wheel loading.

That's exactly the rationale, which on its face seems the most equitable until you consider the impact as a percentage of a persons income.

[John B.]

On Wed, 3 Aug 2022 02:35:03 -0700 (PDT), "funkma...@hotmail.com"

<funkma...@hotmail.com> wrote:

>On Wednesday, August 3, 2022 at 5:05:32 AM UTC-4, John B. wrote:
>> On Wed, 3 Aug 2022 01:40:15 -0700 (PDT), "funkma...@hotmail.com"
>> <funkma...@hotmail.com> wrote:
>>
>> >>
>> >> I can't even guess what y'all are doing "back there" but here any
>> >> truck is considered a working vehicle and thus is subject to lower
>> >> taxes then a "sedan". so a great many people buy pickups :-)
>> >
>> >The state of new hampshire bases its annual vehicle tax on the gross vehicle weight. The owner of a new Mercedes SL6 will pay less tax than the owner of a ten-year-old F-150. You still see far more pick-ups and large SUVs than even moderately priced sedans in new hampshire . Most of them rarely leave the pavement and do little more "work" than fetching groceries, and a significant number of those sport trump stickers with have license plates with such friendly messages as "LBRLHNTR".
>> >
>> What is "gross weight" for registration purposes? Total vehicle weight
>> plus designed maximum load. i.e., 1 ton pickup is total weight of
>> vehicle plus 1 ton?
>
>Yes, vehicle weight plus maximum load
>
>>
>> But in one sense that seems logical as roads are, I believe, designed
>> for a maximum wheel loading.
>
>That's exactly the rationale, which on its face seems the most equitable until you consider the impact as a percentage of a persons income.
>

Well, there are all sorts of grounds for doing things. In New
Hampshire it is, I suppose, cost of road maintenance, here it is how
much money you can spend, but based on engine size (:-) and in
addition after a car is 5 years old (I think it is) you have to have
it inspected each year before the annual registration sticker is
issued. Here once a car is "registered" and plates issued that plate
and registration number stay with the car and you pay an annual "tax"
each year.
--
Cheers,

John B.

[Jeff Liebermann]

On Wed, 3 Aug 2022 02:35:03 -0700 (PDT), "funkma...@hotmail.com"

<funkma...@hotmail.com> wrote:

>On Wednesday, August 3, 2022 at 5:05:32 AM UTC-4, John B. wrote:
>> On Wed, 3 Aug 2022 01:40:15 -0700 (PDT), "funkma...@hotmail.com"
>> <funkma...@hotmail.com> wrote:
>>
>> >>
>> >> I can't even guess what y'all are doing "back there" but here any
>> >> truck is considered a working vehicle and thus is subject to lower
>> >> taxes then a "sedan". so a great many people buy pickups :-)
>> >
>> >The state of new hampshire bases its annual vehicle tax on the gross vehicle weight. The owner of a new Mercedes SL6 will pay less tax than the owner of a ten-year-old F-150. You still see far more pick-ups and large SUVs than even moderately priced sedans in new hampshire . Most of them rarely leave the pavement and do little more "work" than fetching groceries, and a significant number of those sport trump stickers with have license plates with such friendly messages as "LBRLHNTR".
>> >
>> What is "gross weight" for registration purposes? Total vehicle weight
>> plus designed maximum load. i.e., 1 ton pickup is total weight of
>> vehicle plus 1 ton?
>
>Yes, vehicle weight plus maximum load

GVW (gross vehicle weight)
<https://www.lawinsider.com/dictionary/gross-vehicle-weight-gvw>

>> But in one sense that seems logical as roads are, I believe, designed
>> for a maximum wheel loading.
>
>That's exactly the rationale, which on its face seems the most equitable until you consider the impact as a percentage of a persons income.

To be genuinely equitable to the state tax payers, the vehicle tax
would need to be at least 6 times (my estimate) that of a commodity
compact passenger car to pay for damage the monster truck does to the
roads. That's because road wear increased by the 4th power of the GVW
(gross vehicle weight). A monster truck that weighs twice what a
compact car weighs will produce 16 times the road wear:
<https://en.wikipedia.org/wiki/Fourth_power_law>
Notice the bicycle example in the calculations example.

Incidentally, I had a rather expensive example of how that works. I
live on a private road with very little traffic. A few years ago, the
four local propane truck vendors contrived a new "efficiency" scheme
to reduce delivery costs. Instead of waiting for the customer to call
if they need more propane, they visit their customers and top off the
tanks until the delivery truck runs out of propane. The result is a
major increase in propane truck traffic. The road was last resurfaced
in 1989(?) so it definitely needed to be re-paved. The additional
propane truck traffic almost destroyed what was left necessitating an
immediate repair. I've been talking to the neighbors about reducing
the number of propane vendors from 4 to 1, which should reduce propane
truck traffic by an equal amount.

A 3,499 gallon propane truck weight 32,200 lbs when filled to 85% of
capacity. My Subaru has a GVW rating of about 4,000 lbs
32,200 / 4,000 = 8
8 * 8 * 8 * 8 = 4,096
The propane truck does about 4000 times more road damage as my Subaru.
In theory, residents with propane tanks should pay 4000 times more in
road maintenance contributions. In reality, people pay what they can
afford.

Before re-paving in 2014:
<https://goo.gl/maps/H3XjNUQWVp6rK9mf8>
During re-paving:
<https://photos.app.goo.gl/U4cn1ZuMnepBBm9B9>

>> >Oh, and they are the least tolerant of cyclists as well.
>> Over here the law says that slower vehicles will keep to the left side
>> of the road which in practice seems to be bicycles, small motorcycles
>> and heavy trucks and we don't seem to have many problems of that sort.
>> --
>> Cheers,
>>
>> John B.

The reason you see so many monster trucks on the road in the US is
that it saves the buyer of a new car the cost of the "Gas Guzzler
Tax":
<https://www.epa.gov/fueleconomy/gas-guzzler-tax>
<https://en.wikipedia.org/wiki/Gas-guzzler>
"The primary criticism of the tax is that it does not apply to light
trucks."
Anything over 6000 lbs GWV is exempt from the tax. The usual trick is
for the auto companies to make fairly light weight and flimsy trucks,
with overkill ultra heavy duty axles, springs and shocks in the rear
to increase the payload rating. That will result in tolerable gas
mileage, a GVW over 6000 lbs, and a rough ride if someone actually
tries to load the truck with the rated maximum payload.

Also, if you purchase or lease it as a commercial vehicle, you can
depreciate the full value of the truck:
<https://www.sweeneybuickgmc.com/tax-deductions-on-vehicles/>

[John B.]

On Wed, 03 Aug 2022 10:23:46 -0700, Jeff Liebermann <je...@cruzio.com>

You are disregarding a number of facts. Road capacity is designed, or
is in modern times designed, to support specified maximum wheel
weights, sometime referred to as axle weight ... not simply vehicle
weights. and, of course a road designed to support a horse and buggy
probably won't support a loaded propane truck very well.

The above is why, in most countries, they have those "Weight Stations"
along the roads... to control the weight of the vehicles traveling
over it.
--
Cheers,

John B.