Wikipedia:Reference desk/Archives/Science/2019 August 22

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August 22

Pauli exclusion principle

Is the pauli exclusion principle an implicit thing that you can't do anything about (like the whiteness of rice), or is it a force which could in principle be overcome if you applied enough energy? — Preceding unsigned comment added by 2A01:E34:EF5E:4640:3930:E29D:D29A:2480 (talk) 04:49, 22 August 2019 (UTC)

Trying to overcome it, say by squeezing a bunch of fermions together under enormous pressure, simply causes them to move to higher energy levels, rather than start sharing. The apparent force that resists an attempt to do this is often called degeneracy pressure or exclusion pressure. Someguy1221 (talk) 05:16, 22 August 2019 (UTC)

But there is plenty you can do about the whiteness of rice, like getting brown rice, red rice, gold rice, or purple rice; or adding food coloring. Or you can just leave it out after cooking, and it will magically become green rice. :-) SinisterLefty (talk) 11:43, 22 August 2019 (UTC)

Same with sugar. The follow-up to the best joke at the Edinburgh Fringe Festival was:

You can have white sugar. You can also have brown sugar, but dem are rarer.

— Preceding unsigned comment added by 2a00:23c1:e101:4900:f9d6:e449:7b77:7388 (talk) 19:08, 22 August 2019 (UTC)

The Pauli principle is a direct consequence of anti-symmetry of fermionic wave function and as such can not be overcome as it is not a force. Ruslik_Zero 20:07, 22 August 2019 (UTC)

In a sense that's technically correct, but misleading. If fermions keep getting compressed enough to overcome their degeneracy pressure, they get to such high energies that it becomes energetically favorable for them to change into other particles, as detailed in degenerate matter. This is what happens when a neutron star forms; the protons and electrons in the core of a star become compressed so much they transform into neutrons. And if the core exceeds the Tolman–Oppenheimer–Volkoff limit, the collapse continues to form a black hole. As detailed in degenerate matter, what happens in this process is not currently well-understood; the particles may transform to unbound quarks, bosons, or a string fuzzball. There's a Nobel Prize waiting for anyone with the answer. --47.146.63.87 (talk) 21:50, 22 August 2019 (UTC)

Is the liver indeed the largest and heaviest internal organ?

According to this article on Wikipedia as well as many publications, the largest and the heaviest INTERNAL organ is the liver. I never understand it, because I think everyone agrees that the intestine is much more heavier and larger (according to the date that I saw on other site). Isn't it? (See here for example). 93.126.116.89 (talk) 23:39, 22 August 2019 (UTC)

Your link refers to intestines. The large intestine and small intestine are 2 different organs with different functions. 41.165.67.114 (talk) 06:02, 23 August 2019 (UTC)

Seems there's some confusion of terms here. The liver would be the largest internal organ by mass ("heaviest"), but the large and small intestines are each larger by linear extent ("length"). The source used for the claim of largest organ does not specify, but it can only logically be by mass. I have modified our article appropriately.--Khajidha (talk) 11:32, 23 August 2019 (UTC)

PS - several other claims in our article say only that something is "the largest", without explaining if that means mass, length, volume, or cross section. --Khajidha (talk) 11:33, 23 August 2019 (UTC)

If not specified, I would take "largest" to mean volume. And in the case of body organs, most have about the same density, so the largest volume likely also means the largest mass. SinisterLefty (talk) 11:57, 23 August 2019 (UTC)

In the comparison with intestines, two points:

1) They are likely counting the small and large intestines separately.

2) They are surely excluding the contents of the intestines. SinisterLefty (talk) 11:57, 23 August 2019 (UTC)

• As appealing as such comparisons are, it's a bit arbitrary, isn't it? It's all a matter of how humans have chosen to draw boundaries, without absolute criteria. Should the "liver" include the gall bladder (since the latter is just a contractile reservoir for the principal product of the liver's epithelial surface)? Should "intestine" include its pedicle (the omentum), the stomach, the visceral peritoneum? Which dimensions should be used to measure/compare? If we use mass, should it be average immediately after removal from the body (at what age, what allowance for disease), after fixation, after dessication? Of course we have conventional answers for these things - and our articles adhere to reliable sources - but many of the decisions are historical and/or arbitrary. — soupvector (talk) 12:52, 23 August 2019 (UTC)