SI-Unit thread

[Anonymous No.10145705]

Today the CGPA voted for the redefinition of the kilogramm. Why is nobody talking about this?

>Current definition: The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.
>2019 definition: The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.62607015×10−34 when expressed in the unit J⋅s, which is equal to kg⋅m2⋅s−1, where the metre and the second are defined in terms of c and ΔνCs.

Some sources:
https://www.bipm.org/en/news/full-stories/2018-11-si-overhaul.html
https://en.wikipedia.org/wiki/Redefinition_of_SI_base_units

About damn time, if you ask me. Using a prototype kilogram was a disgrace to every theoretical physicist.

[Anonymous No.10145722]

>mfw burgers are still using their retarded arbitrary made up bullshit system

There is no excuse.

[Anonymous No.10145735]

>>10145722
>mfw burgers are still using their retarded arbitrary made up bullshit system

What the fuck do you think yours is? What do you think any "unit of measurement" is?

[Anonymous No.10145791]

>inb4 these physical "constants" used for defining the SI units actually vary with respect to time and or space, but we will forever stay ignorant of that fact now, because we have based our whole unit system on them

I mean there is really now proof that these constants are actually constant. Up to now we only did measurements in a very very very confined region of space, when considered at a cosmological scale. Same with time.

[Anonymous No.10145802]

>>10145735
>>10145791
>t. mad burgers

[Anonymous No.10145893]

McDowell has some interesting thoughts on the change: https://twitter.com/planet4589/status/1063441971048534021

[Anonymous No.10146051]

Some german nerd went to the conference:
http://blog.wolfram.com/2018/11/16/as-of-today-the-fundamental-constants-of-physics-c-h-e-k-na-are-finally-constant/

[Anonymous No.10146060]

>>10145705
>Why is nobody talking about this?
Because it has no affect on the Great American Pound

[Anonymous No.10146101]

>>10146060
>The majority of U.S. customary units were redefined in terms of the meter and the kilogram with the Mendenhall Order of 1893 and, in practice, for many years before.
https://en.wikipedia.org/wiki/United_States_customary_units

Yeah, nah.

[Anonymous No.10146132]

My question is how did we find the exact values of constants?

[Anonymous No.10146161]

>>10146132
see>>10145735

[Anonymous No.10146192]

>>10146132
We did not. The new definitions turn everything upside down. We now DEFINE the constants as having a certain EXACT value, like planks constant being 6.62607015 * 10^blah. You can then use experiments, measuring these constants to actually compute the primary units like meters/ampere/etc.
Ofc the value 6.62607015 is not quite arbitrary, but comes from the value we previously measured that constant with our old unit system. Doing this has the advantage, that the actual scale of all units does not change at a magnitude that matters in practice.
Another advantage is that everyone can now calculate the base units by themselves as long as they have ANY kind of measuring equipment and don't have to run to Paris each time.

[Anonymous No.10146209]

So everything is everything now. Joules are K, mass is gravitational radius... neat

[Anonymous No.10146443]

>>10146209
I think this is the wet dream for physicists, the possibility of reinterpreting all of the physical laws in science by pure natural universal constants.

[Anonymous No.10146507]

>>10145705
But... they're both a kilogram

[Anonymous No.10146751]

[Anonymous No.10146752]

>>10146192
this

[Anonymous No.10146792]

>>10146507
Get with the times, grandpa. Le Grand K is now old and busted.

[Anonymous No.10146808]

You ever wonder if the true value for physical constants are just transcendental numbers that we'll never find?

[El Arcón No.10147304]

>>10145705
>Why is nobody talking about this?
business as usual

[Anonymous No.10147315]

>>10145705

[Anonymous No.10147317]

>vacuum permittivity is no longer a constant and fundamental charge is

This upsets me.

[Anonymous No.10147765]

>>10147315
Hahahaha that shit is pure comedy

[Anonymous No.10147767]

>>10145722
Burger units are defined by SI units.

[Anonymous No.10147782]

>>10145791
We will just redefine them again.
The most important thing is that they are tied together, so that if the Planck constant does change somewhere in space, or time, a kilogram WOULD be different to what it is here and now.

[Anonymous No.10147787]

>>10145705
Cause it's fucking unnecessary. This does not contribute to science in any way. Can just imagine some retarded useless physicist who thought this was a good way to waste some time.

For real though, I don't see how this helps real science in any way.

[Anonymous No.10148116]

>>10145735
>what is quantum mechanics
>what is quantized
The plank scale is only arbitrary in that it happens to be what it is, which is a question for metaphysics.

[Anonymous No.10148135]

>>10147787

You don't see any problem with the fact that you have to travel to France if you want to know what a kilogram is?

[Anonymous No.10148260]

>>10148116
>what is quantum mechanics
"quanta" of what?
>what is quantized
Yeah...What IS "quantized"?

>The plank scale is only arbitrary in that it happens to be what it is, which is a question for metaphysics.
Was there even a need to reply to me?

[Anonymous No.10148491]

>>10147787
>>10148135
And this is not arguing the fact that the Kilogram is changing over time. The platinum-iridium Kilogram was supposed to be stable, but it changed, and the worst part is that nobody knows if it was the result of gained mass or lost mass.

[Anonymous No.10148497]

>>10148260
Are you fucking retarded? Why are you on /sci/???

[Anonymous No.10149061]

>>10145722
yep. a metric system that lets unit of measurement by 5 is much superior to being able to divide by 3 or 4!

especially when the meter was created to be based on the distance from the equator to north pole through Paris, and has more of an error than the inch has when measuring 1/500millionth of the polar diameter

[Anonymous No.10149067]

>>10146443
then instead of using the meter, they should use a unit of distance which actually is a universal constant.

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

[Anonymous No.10149110]

>>10148497
A-anon I...

[Anonymous No.10149262]

>>10149067
This is indirectly how the meter is defined. It's defined in terms of the (fixed) speed of light and the second, which is defined in terms of the frequency of a transition in Caesium. Which is equivalent to picking some other transition like the 21 cm line. So you're complaining about the meter not being defined in a way which is completely equivalent to how it is defined.

Not sure if bait or just stupid.

[Anonymous No.10149269]

>>10147765

[Anonymous No.10149271]

>>10146209
>So everything is everything now
Yeah, this is basically the relations between the new units.

[Anonymous No.10149274]

>>10149271
In comparison with the old ones.

[Anonymous No.10149374]

>>10149061
The superiority (in at least anything other than measuring something person-sized) comes from consistency.
https://www.britannica.com/science/British-Imperial-System
16 drams to an ounce, 16 ounces to a pound, then 14 pounds to a stone (or other versions where the numbers were all over the place).
Liquid measures get even less consistent: US measures from gallons downward goes 4 - 2 - 4 - 4 - 8 - 60, British goes 4 - 2 - 4 - 5 - 8 - 60
Lengths give me a headache to look at in general.
I understand that some of them are better for everyday use, but when people are brought up with a system where all measurements are relative to each other in simple ways it just makes things easier.

Personally yes I would prefer a dodecimal system too, but we're not getting twelve fingers and/or rewriting our entire number system any time soon.

[Anonymous No.10149387]

>>10145722
The base-12 system of feet and inches is still used in time measurement by everyone and is based on Sumerian technology which is the oldest that exists.

[Anonymous No.10149393]

>>10149387
>system of feet and inches is still used in time measurement
I'm not sure you meant to run those two together