B Is 3-point of H20 used for Kelvin a certain set of isotope

AI Thread Summary
The discussion centers on whether the triple point of water, used to define the Kelvin, is based on specific isotopes like Hydrogen-1 and Oxygen-16. It questions if using different isotopes would significantly affect measurement accuracy, especially considering varying isotope occurrences in extraterrestrial water. The term "Vienna Standard Mean Ocean Water" highlights the geocentric assumption that Earth's water isotopic composition is universal. This presumption may pose issues as the Kelvin definition is set to be redefined. The conversation emphasizes the implications of relying on Earth-centric standards in scientific measurements.
swampwiz
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If I had had enough space to enter the proper question, it would have been:

Is the triple point of water which is used for the definition of the unit of Kelvin defined as water having a certain isotopes such as 2 Hydrogen-1 & 1 Oxygen-16?

Or would the error introduced by using different isotopes not make a difference up to the level of desired accuracy - or is there a defined occurrence of the various isotopes? It seems that the water that exists outside of the Earth could have a different isotope occurrence, and therefore presuming that water everywhere in the Universe has the same occurrence of the isotopes as on Earth would be a gaiocentric presumption.
 
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Google "Vienna Water."
 
Actually "Vienna Standard Mean Ocean Water". Searching for "Vienna Water" brings up the water works for Vienna, VA, LOL.

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

So the definition does use a gaiocentric presumption. I suppose that it has to be this way.
 
swampwiz said:
nd therefore presuming that water everywhere in the Universe has the same occurrence of the isotopes as on Earth would be a gaiocentric presumption.

Why is this bad? (Especially as the Kelvin is about to be redefined)
 
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