1

Physics, Astronomy & Cosmology / Re: Is mass a number?

« on: 02/05/2022 18:59:59 »

Hi all,

OK varsigma,
If I understand your request correctly regarding is mass a number rather than a physical thing.
Its based on empirically proven physical constants, to allow precise replication. 

So the unit of mass is the Kg Kilogram in the system of international units, which was originally simply the mass of a litre of water, which is actually accurate to 30 parts per million.

However in 1799, it was replaced by an all-platinum kilogram prototype that was fabricated with the objective that it would equal, as close as was scientifically feasible for the day, the mass of one cubic decimetre of water at 4 °C. It was called the Kilogramme des Archives as it was stored in the Archives Nationales in Paris.

This remained the SI standard till 2019.
https://en.wikipedia.org/wiki/International_System_of_Units

The kilogram was the last of the SI units to be defined by a physical artifact, although precision kilogram masses remain in use as secondary standards for ordinary purposes.

https://en.wikipedia.org/wiki/Kilogram#Redefinition_based_on_fundamental_constants

The requirement to produce replicas caused  the mass of these to vary by amounts approximately 50 micro grams.

Therefore,

The International Committee for Weights and Measures (CIPM) approved a redefinition of the SI base units in November 2018 that defines the kilogram by defining the Planck constant to be exactly 6.62607015×10−34 kg⋅m2⋅s−1, effectively defining the kilogram in terms of the SI base units  "second" and the "metre".

Therefore, dimensions of energy times time, (mass × length^2 / time) together with other physical constants
This was done so that the standard can be independently reproduced in different laboratories by following a written specification, from empirically proven physical constants.
And the units were coherent to mass length and time.

https://en.wikipedia.org/wiki/Kilogram#Acceptance_of_the_Giorgi_system,_leading_to_the_MKSA_system_and_the_SI

To summarize, the ultimate reason that the kilogram was chosen over the gram as the base unit of mass was, in one word, the volt-ampere. Namely, the combination of the meter and the kilogram was the only choice of base units of length and mass such that 1. the volt-ampere—which is also called the watt and which is the unit of power in the practical system of electrical units—is coherent, 2. the base units of length and mass are decimal multiples or submultiples of the meter and the gram, and 3. the base units of length and mass have convenient sizes.

It would appear the Kibble balance is the dominate apparatus in this regard.

 https://en.wikipedia.org/wiki/Kibble_balance


which hopefully the design/engineering  explains  to you how mass is not just a number but a based on combination of physical constants allows a very accurate replication of fixed amount of Mass.

A conducting wire of length L that carries an electric current I perpendicular to a magnetic field of strength B experiences a Lorentz force equal to the product of these variables. In the Kibble balance, the current is varied so that this force counteracts the weight w of a mass m to be measured. This principle is derived from the ampere balance. w is given by the mass m multiplied by the local gravitational acceleration g

weight = mg = BLI

https://en.wikipedia.org/wiki/Lorentz_force

2

Question of the Week / Re: Can the Earth be used as a dynamo?

« on: 02/05/2022 12:17:29 »

Hi all

Thanks for that Evan, my bold

- Some have even recently speculated (based on seismology) that the remnants of Theia's core are still sinking to coalesce with the Earth's core
- This causes convection currents in the outer core
- This interacts with the rotation of the Earth to generate electric currents in the outer core, which generates the Earth's magnetic field

As you state there is still a lot of speculation in this regard, and some of the modeling being done is even testing the capacity of super computers.
But there are some fundamentals required in these models

eg,   conversion of kinetic energy to magnetic energy, and a requisite is part of the Kinetic energy is provided by planetary rotation.

So the point raised by wolfekeeper remains.

Along with the similarity to the work heat equivalence experiments of Joule, we can observe as the friction with local geography of the solid earth passes/interacts with these tidal bulges, due to its rotation.

3

Question of the Week / Re: Can the Earth be used as a dynamo?

« on: 01/05/2022 17:53:17 »

Hi all

Trying to develop energy from the mechanical rotation of the earth would involve insurmountable difficulties despite being theoretically possible.An isolated structure that is static with reference to the rotating earth or rotating with a shorter or longer period than the earth would be required first. then this structure would be required to follow the track of the earth around the sun.Not at all practical and i'm sure there could be other difficulties involved.

Does the tidal bulge not satisfy those requirements ?

If so its pretty straight forward and is already being done.

https://en.wikipedia.org/wiki/Tidal_power


Also the tidal effects due to the Moon are greater than due to the Sun

http://hyperphysics.phy-astr.gsu.edu/hbase/tide.html#:~:text=Go%20Back-,Sun's%20Tidal%20Effect,gravity%20field%20across%20the%20Earth.

4

Question of the Week / Re: Can the Earth be used as a dynamo?

« on: 30/04/2022 09:57:18 »

Hi all,

So wolfekeeper you raise an important contradiction to evan_au posts.

Less directly, the spinning of the Earth interacts with the gravitational pull of the Sun and Moon to generate ocean tides, and the tidal currents can be used to generate electricity.

No water is pumped up in the suns and moons gravitational field and no friction occurs as the solid Earth rotates passed these bulges ?

The Earth spinning does set up electric currents in liquid iron in the outer core of the Earth. This generates the Earth's magnetic field, which shields our atmosphere from the solar wind.

what powers this generation of electro magnetic currents ? and how is it isolated from placing a load on the rotation of Earth ?
 

5

That CAN'T be true! / Re: where does Colin's sailing boat, energy and momentum come from ?

« on: 13/04/2022 10:55:57 »

Hi all,

BC

You also seem not to recognise that, on any given day, the angular momentum of the atmosphere may be a bit higher or lower than the average

So to be clear, I believe it is possible the average angular momentum total fluctuates, for the reasons given previously,
the sharing of angular momentum between the atmosphere and the solid earth became the go to explanation of the underlying annual fluctuation.

I believe it can be explained as terminal velocity.

   
BC

It is conserved because there is no torque acting on the system (apart from a few thing we have discussed, such as the tides).

That indeed is the current thinking, which I believe falls short of the physical reality, I think there is potential alternative explanations as to the fluctuations of LOD that indeed require forces not yet identified.

To explain these forces although a simple mechanism, I will have to go across a broad range of examples and correlations of physical events.

For example a potential link to galaxy rotation curves and G 

 

6

Chemistry / Re: What happens when you melt gold into glass?

« on: 10/04/2022 13:06:08 »

Hi Marcos,

Quite a while ago I bought a piece of art from these people local to me, which I believe utilizes some of the specialist techniques/knowledge you are requesting.
 
https://www.greenhalghglass.co.uk/gallery.html

7

General Science / Re: Antarctic science greenhouse emissions

« on: 10/04/2022 12:53:18 »

HI all,

So BC,

Or they hit the top of a mountain

I'm not sure what your point is there given Alan's post.

I believe he was making the point of  coral conditions, are you referring to seamounts ?
 

8

General Science / Re: At what gravity does a person run the fastest?

« on: 04/04/2022 23:45:21 »

Hi all,

Halc, yes I take your point regarding gear equivalence for skating technique, its not my strong suit, think Bambi on ice and you have a pretty good visualization.

Take a look at the link below it covers some of the points as to the physics.

It does state, the mechanical advantage of the  pedal system of gears does allow a much greater Tyre speed vs leg speed.
 
https://physics.stackexchange.com/questions/505636/what-determines-the-top-speed-in-ice-skating

I believe someone raised the point of the similarity with sailing dynamics as to forward motion gained from a side on wind.
 

9

General Science / Re: At what gravity does a person run the fastest?

« on: 01/04/2022 15:04:27 »

HI all

Halc

I did think about why bikes are faster than skating. Biking seems almost 100% efficient, almost all the mechanical energy going into forward thrust, whereas the skater is thrusting against his own inertia, sending his center of gravity from side to side. That's a lot of work, even though half of it is negative work being done. The human body doesn't capture negative work very well. Again, a kangaroo does. They're designed to absorb the energy of coming down and bounce back up again, using energy only to add to it a bit. Hence the skater wasting a lot of energy that the cyclist doesn't

Bikes have gears which would account for the faster speed 

rather than straight comparison of energy efficiency

https://www.popularmechanics.com/adventure/outdoor-gear/a22061530/how-bike-gears-work/

10

Question of the Week / Re: QotW - 22.03.21 - Does relativity make rocks on the moon older than Earth rocks?

« on: 27/03/2022 10:09:51 »

Hi all,

I think we maybe wondering a little from the original question, however given eternal student's last comment, it maybe relevant to flag up you have to be careful with your comparisons/analogy's


ES

A planet is a mole-hill in the area, everything is really on the slopes of Mount Everest anyway.

     

I believe using the word slope in this context is misleading and will bring you back to the same issue Janus raised regarding gravitational time dilation error in the wording of the original question.

Given the slope of the well tells you how hard the pull of gravity is at that point.

The depth of the well tells you how much energy it takes to escape.

https://en.wikipedia.org/wiki/Gravitational_potential#/media/File:GravityPotential.jpg

 

11

Question of the Week / Re: QotW - 22.03.21 - Does relativity make rocks on the moon older than Earth rocks?

« on: 25/03/2022 00:49:51 »

HI all,

Ok to have a stab at putting an approx value to the original question for gravitational time dilation due only to their gravity well.

using the analogy of a rock split in half from the surface of the earth and each half remained on the surface of their respective bodies, from an impact event occurring 4.51 billion years ago

Earth time dilation = 6.965 x 10^-10 sec/sec

Moon time dilation = 3.15 x 10^-11 sec/sec

I get the Earth to be 1095 days younger than the moon which may seem like a lot but is only

                                            66.51 x 10^-9 % different

I am happy to be corrected if anyone else wants to chip in.
 

12

Question of the Week / Re: QotW - 22.03.21 - Does relativity make rocks on the moon older than Earth rocks?

« on: 24/03/2022 14:12:32 »

Hi all,

Thank you Janus for that response, it sits better with me than the previous analogy of a gravity field not following the inverse square law.

If I may borrow part of your explanation to respond, and explain why/how I understand your statement is correct :

Janus
 

First off, the time dilation is not due to a difference in the strength of gravity, but to a difference in gravitational potential.

So firstly if you calculate the strength of g and escape velocity and time dilation at the Earths surface gives

                                    g  = 9.82 m/s^2
             escape velocity  =  11.19 x10^3 m/s
                  time dilation  =  + 6.97 x10^-10 sec/sec

Then to borrow your example:
 "Now double the Earth's radius and quadruple its mass"

Lets call this plant B gives the following equivalent values.

                                g  = 9.82 m/s^2
             escape velocity  =  15.82 x10^3 m/s
                  time dilation  =  + 1.39 x10^-9 sec/sec

As can be seen the identical value of g for Earth and planet B at their surface, but a different value for escape velocity and therefore gravitational time dilation.

 

13

Question of the Week / Re: QotW - 22.03.21 - Does relativity make rocks on the moon older than Earth rocks?

« on: 23/03/2022 00:00:38 »

HI all
Janus

First off, the time dilation is not due to a difference in the strength of gravity, but to a difference in gravitational potential.
To illustrate the difference, imagine you had a uniform gravity field (one that did not change in strength with altitude). If you place two clock at different heights in this field, the higher clock runs faster even though it feels exactly the same gravitational force as the lower clock.

Has this been shown experimentally, if so could you provide information please.

14

Physics, Astronomy & Cosmology / Re: Is there a net heat exchange between water and ice at 0 degree C?

« on: 20/03/2022 01:21:44 »

Hi all,
 Hamdani you raise a interesting scenario,

BC

Energy will flow until equilibrium is achieved.

It was already at equilibrium.

I am not sure that statement is totally correct, if you consider the energy imbalance between the two sides as described,
for example the latent heat/energy is unbalanced as is the kinetic energy of the molecules, also the density's.   

15

That CAN'T be true! / Re: Are Flat Earthers really for real?

« on: 02/03/2022 01:09:43 »

Hi all

Yes I believe some of them are for real, even one of the pioneers of the flat earth society,
https://en.wikipedia.org/wiki/Lady_Elizabeth_Blount
was from/one of the;
 https://en.wikipedia.org/wiki/Intelligentsia

There was some interesting characters and happenings around the;
https://en.wikipedia.org/wiki/Bedford_Level_experiment

Local to TNS

 

16

Physics, Astronomy & Cosmology / Re: Has the distance between the sun & earth changed?

« on: 26/01/2022 01:06:07 »

Hi all 

Ok  Halc you make a lot of valid points, and as you have already stated not much to do with the original post, so I will probably start another post around the apparent change of opinion regarding energy's influence in the dynamic you were describing.

Halc : my bold

1) Solar tides, driving Earth away from the sun, energy being supplied by spin of Earth.

Changes to this in your following post,

It isn't an energy thing. The vast majority (over 99%, about 97% for lunar tides) of the energy dissipates as heat. Its the angular momentum that counts since that cannot just be radiated into space,

Given you state the energy is supplied from the earths rotation and radiates out into space, you cannot dismiss/separate the relationship between rotational momentum and rotational kinetic energy of a body.

(energy is the currency of the physical world)





http://hyperphysics.phy-astr.gsu.edu/hbase/rke.html

17

Physics, Astronomy & Cosmology / Re: Has the distance between the sun & earth changed?

« on: 25/01/2022 00:05:47 »

Hi all 

Halc you raise some interesting points.
The primary drivers of the changing average distance of Earth is (in decreasing order of significance):
1) Solar tides, driving Earth away from the sun, energy being supplied by spin of Earth.
2) Mass of sun decreasing, also driving Earth away as solar gravity cannot maintain the orbital distance
3) Friction with meteors and such, driving the orbit lower
4) Gravitational waves, decreasing the orbital energy at the rate of about 200 watts.

Could we explore them please,
1) I am assuming this refers to the delta of the suns field across the Earth, due to the inverse square law and the frictional coupling between the solid surface and the tidal bulge effectively forcing the bulge ahead of there center lines, therefore constantly pumping water up in the Sun's gravitational field.
What value of energy are you placing on this aspect from the spin of the Earth ?

2) I believe I understand this point

3) Why does the friction of meteors favour one direction ?

4) Could you expand where/how the rate of 200 Watts is derived for the Earth Sun orbital energy/distance.   

18

That CAN'T be true! / Re: where does Colin's sailing boat, energy and momentum come from ?

« on: 11/09/2021 10:54:13 »

Hi all,

BC

If the loss is (on average) isotropic then the net change in momentum is (on  average) zero

The problem with that statement is the frictional coupling between the solid earth and its atmosphere converts  anisotropic motion to isotropic motion.

Also as stated previously, the the Non inertial conditions of the system that generates forces that can and does accelerate/change the momentum of a droplet of a fluid by altering the gradient of the pressure due to the dynamics of changing density in a gravity field due to the incoming/outgoing flux of radiation to the Non isolated non inertial system under consideration is an example of anisotropy due to bulk flows of fluid with a background effect due to density, therefore favoring a specific direction.

So the problem still remains, a daily change in angular momentum vector due to friction ending up as momentum with a positive value but no longer having a net direction to transfer back to maintain/conserve the LOD

Moving on to the points regarding following the energy of the interactions I am highlighting here its the patterns of the fluctuations that could give a insight to the dynamics.
So looking at the annual 3 milli second variation in LOD ( Δ = 1.4477 x 10^22 Joules/day ) 

Given it was down to a necessity to explain the newly discovered three millisecond annual variation in LOD I believe it was the explanation of its time, but I believe there is alternative explanations that will be more satisfactory.
 
https://syrte.obspm.fr/astro/journees2019/FILES/salstein.pdf

The earliest observations of changes in length of day were made at Paris Observatory by Stoyko
and Stoyko (1936), who observed the annual variation of length of day. In 1948, Victor Starr of the
Massachusetts Institute of Technology (MIT) noted that the atmosphere need not conserve angular
momentum, and could share it with the Earth below. Starr started the General Circulation Project
at MIT, and one of its features was calculations of fluxes and changes in atmospheric angular
momentum.

BC

As Paul Simon said, "the problem is all inside your head"
"The answer is easy , if you take it logically."

This "a daily change in angular momentum vector due to friction "
Just isn't real.

Its funny you should take the lyrics route to make a point, because I intend to do similar to start the explanation as to the real dynamics occurring.

Daft Punk Lyrics:

"Like the legend of the phoenix
Our ends were beginnings
What keeps the planet spinning
The force from the beginning"


So look out for "Are you a Daft Punk or a Newton of drift theory ?"

https://earthobservatory.nasa.gov/features/Wegener/wegener.php

19

That CAN'T be true! / Re: where does Colin's sailing boat, energy and momentum come from ?

« on: 10/09/2021 00:13:21 »

Hi all

BC

In every single collision between any two atoms or between atoms and photons or phonons, momenta and energy are conserved.
So they must be conserved in every sequence  and combination of collisions.

How does the addition work for a non isolated system ?
https://en.wikipedia.org/wiki/Thermal_radiation

BC

I pointed out that sound waves spread in all directions, so their vector sum is zero.
That cover it nicely.

I think if you look back that was me.

gem

The problem with that is,
the momentum and energy of sound  is carried off in all directions.

which brings us back to, how is the vector direction total maintained for later transfer back to the angular momentum of the solid earth, due to the partially inelastic collisions sending momentum away from the transfer point, in all directions ?

So the problem still remains, a daily change in angular momentum vector due to friction ending up as momentum with a positive value but no longer having a net direction to transfer back to maintain/conserve the LOD

Indeed the random motion of particles can decrease/increase depending on the balance of incoming/outgoing flux of radiation to the Non isolated system under consideration.

Also given the Non inertial conditions of the system this generates forces that can and does accelerate/change the momentum of a droplet of a fluid by altering the gradient of the pressure due to the dynamics of changing density in a gravity field due to the incoming/outgoing flux of radiation to the Non isolated non inertial system under consideration.

20

That CAN'T be true! / Re: where does Colin's sailing boat, energy and momentum come from ?

« on: 09/09/2021 00:06:57 »

Hi all,

If we consider the approximate 0.3 of a milli second variation for one day given in the dates earlier, corresponds to a change in rotational kinetic energy of the solid earth in the region of 1.6 x 10^21 joules for the day in question.

I realise it's terribly "English" to always talk about the weather but...

We are talking about the momentum transfers which definitely sum to zero over the long term.
You are talking about the transfer of heat from the earth to the air.
And that's broadly what drives the weather.
So it is irrelevant.

The hint is in the units.

MMMMM, I believe we already covered the universal link (momentum = energy/phase velocity.)
and if you look at the original question, the units for energy are correct and relevant, to put a scale to what you tried to dismiss as close to zero.
However if you prefer a 0.3 milli sec daily variation in LOD should give a corresponding  ±Δ angular momentum

of aprox = 2.019 x 10^25  Kg m^2  for the day in question

Evan_au

I don't know where the variation of 0.3ms in one day came from. This quotes an annual change, not a 1 day change.

You probably need to look back to post 60 and a few on from there.

But to help, the LOD tends to skip about quite a bit more than you believe, also it has an annual speeding up in the northern hemisphere's summer and slowing down in its winter to a well established pattern of ± 1.5 milli sec as per the link below.

https://en.wikipedia.org/wiki/Day_length_fluctuations#/media/File:Deviation_of_day_length_from_SI_day.svg


And bringing that data into closer detail

https://datacenter.iers.org/singlePlot.php?plotname=FinalsDailyIAU1980-LOD-BULA&id=12