Wikipedia:Reference desk/Archives/Science/2022 August 7

= August 7 =

If liquid nitrogen weren't so cold, could you safely drink it?
I guess there's not much to elaborate on. If you were somehow able to get liquid nitrogen at like, idk 5C, would it be safe to drink? What would it taste like? (Also curious about the same thing but with liquid helium/oxygen/carbon). 2601:401:101:37B0:BC00:E8A5:6A1C:69AF (talk) 01:09, 7 August 2022 (UTC)
 * Speaking from personal experience and having had too many prankster friends, it rapidly boils off your body without imparting much cold, and it is odorless. N2 has a triple bond, and is quite chemically inert, so there can be no taste. I have heard that people have suffered from freeze injuries and burst stomachs from ingesting liquid nitrogen. These reports may be apocryphal. Abductive  (reasoning) 02:10, 7 August 2022 (UTC)
 * Ingesting any gas (or liquid that will soon become a gas) is not generally recommended (belching, bloating, farting, discomfort). As liquid nitrogen ice cream is common I would agree that it should be odorless and tasteless, but I disagree that that should be the case for all inert substances: note the smell of space. Carbon -- even elemental carbon -- takes many forms (char and soot are different things) but they all probably taste a heck of a lot worse in pure form than the very thin layer of black char you get on a fire-roasted marshmallow. You could just try drinking liquid smoke. SamuelRiv (talk) 02:33, 7 August 2022 (UTC)
 * Beyond the risk of farting yourself to death, you'd also run the risk of displacing oxygen from your lungs as the liquid nitrogen boiled. Breathing in inert gasses can kill you... AndyTheGrump (talk) 02:38, 7 August 2022 (UTC)
 * The question is about drinking. GI tract only. SamuelRiv (talk) 02:43, 7 August 2022 (UTC)
 * Liquid nitrogen cocktail reports on an injury from drinking a something containing LN2. DMacks (talk) 03:18, 7 August 2022 (UTC)


 * Didn't another IP ask this question a few months ago? ←Baseball Bugs What's up, Doc? carrots→ 03:50, 7 August 2022 (UTC)


 * OP here - searched and didn't see anything about if it wasn't so cold. I guess also should've clarified - if it weren't so cold and it stayed a liquid. 2601:401:101:37B0:B45C:A922:3DE6:AABF (talk) 01:37, 8 August 2022 (UTC)
 * Nitrogen, when liquid, is very cold and will cause damage by freezing (of tissue) and boiling (of nitrogen), but if we could magically keep it a liquid at body temperature, it's just a chemically inert liquid. Nitrogen isn't poisonous and only narcotic at partial pressures well above atmospheric. Other than possibly disrupting you digestive system, it won't do anything. Helium, same story. Oxygen, almost the same. It isn't inert, but pure oxygen isn't very dangerous to humans (on a short term). Be careful not to add an ignition source. Carbon has a triple point of about 4600 K, 10.8 MPa, so below that temperature and pressure you can't make it a liquid, but if we magically could, ... Well, I don't know the chemical properties of magically liquid carbon. Solid carbon may bond to all kinds of stuff in the intestines, preventing absorption by the body, and magically liquid carbon might be even better at that. I wouldn't want to try. PiusImpavidus (talk) 08:11, 9 August 2022 (UTC)
 * But see Activated charcoal (medication). Alansplodge (talk) 10:53, 10 August 2022 (UTC)

Humans in Arabian Desert
I wonder how accurate is information about Humans in Arabian desert, as described in Britannica, particularly this phrase: Humans have inhabited the Arabian Desert since early Pleistocene times (i.e., about 2.6 million years ago). Artifacts have been found widely, including. Some Arab are using it to argue they are not originated from modern humans in Africa. Almuhammedi (talk) 05:36, 7 August 2022 (UTC)


 * It's too bad that Britannica doesn't cite sources. I haven't found anything reliable to support early Pleistocene habitation. There have been recent discoveries supporting as early as 400k years ago at a site known as Khall Amayshan 4, which falls within the Pleistocene epoch. Searching for "Khall Amayshan 4" will find plenty of sources, in reference to a 2021 article in the journal Nature: (https://www.nature.com/articles/s41586-021-03863-y). 2603:6081:1C00:1187:ECDB:8839:6640:BB74 (talk) 07:07, 7 August 2022 (UTC)


 * These can hardly have been anatomically modern humans (Homo sapiens), of which the currently earliest known fossils (Jebel Irhoud, Florisbad Skull) do not date to much earlier than 300,000 years ago. The early expansions of archaic humans out of Africa are currently thought to have started between about 2.1 million and 0.2 million years ago. --Lambiam 10:06, 7 August 2022 (UTC)
 * In any case, the Arabian peninsula is close to and contiguous with East Africa, and was even more so in the past when the Red Sea Rift was narrower and sea levels lower. For "East African" human and other species, the area now occupied by the Arabian desert (which in various past eras would have been less desertlike, just as the area of the Sahara was) would have been part of their normal range. {The poster formerly known as 87.81.230.195} 90.196.45.159 (talk) 12:26, 7 August 2022 (UTC)
 * Somewhat off-topic here but I once worked for a Muslim boss, Egyptian. His PhD and undergrads were in engineering, but he believed Arabic was the oldest language of all. So I asked him is that what Mesopotamia spoke? And he said he never heard of Mesopotamia. Sounds like he might deny humans originating from Africa too. 67.165.185.178 (talk) 12:44, 7 August 2022 (UTC). Also, Arabic was never spoken in Mesopotamia, it was Sumerian than slowly replaced with Akkadian. 67.165.185.178 (talk) 12:48, 7 August 2022 (UTC).
 * Now, I'm not saying that guy was right, or wrong - I'm not participating in that discussion... ultimately, I don't think it's particularly interesting that "one guy may have been wrong, this one time." That phenomenon - a person who is misinformed or undereducated repeating a wrong fact - is really very frequent and ultimately uninteresting.
 * But ... in my mind,... the interesting questions emerge: what is the Arabic-language word for the Akkadian language? What is the Arabic-language word for "Mesopotamia"?  I know a few expert researchers who could go off on a tangent telling you why some words - especially English-language words - are problematic when we use them as place-names.  And in the Middle East, where there are additional sensitivities around place-name, language, and history... oh boy!  If that place is in the middle, what is it east of?  East of... central Europe?  It turns out that there's an entire field of study about how problematic this field of study is, and one of the most famous books - Edward Said's Orientalism - talks all about how the depiction of "the East" is ... well, not only problematic, but at its core is an intentional perpetuation of racism, colonialism, and imperialism to further a particular agenda.
 * Well, we do have an article, if you can read it. And we have this one, too.  Interestingly, the place-name "Mesopotamia" is not one with an English origin... it's one that evolved from Greek and was brought back into the mainfray of European language because somebody who knew how to read and write classical Greek translated it for you into a language and lettering scheme you can read.  I wonder, what language did they use during their translation, and if that language predated the modern English language, what English-name got attached to it later?
 * One of my most favourite books is lovingly titled The Levant. There is a foreword in which the authors explain why they chose that word - Levant - a word that is less commonly used in the English language - to describe ... a concept, a culture, a place, ...
 * I mean, if you can use the same word, "English," to describe both the language that you speak today, and the gibberish that was used to notate Beowulf, aren't you imposing a false sense of continuity across time and place, and doesn't that impart some kind of political innuendo? Who are you to say that a person living in Basra must use two different word-names to distinguish their language from the version that was spoken there centuries ago?  And why do you get to pick the name of that ancient language?
 * Having spent a little time asking and answering this (and related questions), I think it's also important to link to our article on historiography. The way that you know and learn history is different than the way that others know and learn history.  To presuppose that one of these is the correct history, without deep, deep, lengthy study, is a bit ... culturally relative, isn't it?
 * Nimur (talk) 17:47, 8 August 2022 (UTC)
 * Per Nimur, see also A language is a dialect with an army and navy. -- Jayron 32 12:37, 10 August 2022 (UTC)
 * Given the strength of its army and navy, the American language must be the most languagey language in the world. Iapetus (talk) 09:13, 12 August 2022 (UTC)
 * Oooo, . We are at the start of the International Decade of Indigenous Languages with UNESCO behind it.  Martin of Sheffield (talk) 09:46, 12 August 2022 (UTC)

Hubble exposure time allocation per orbit
I'm having trouble finding how LEO space telescopes like Hubble manage long exposure times to minimize dead time. I found details on how time is allocated to HST projects, but let's say one observation requires several hours of exposure from Hubble: did it point at the object for 55 minutes and then uselessly at Earth for the next 41 minutes (it would take 15 minutes to turn 90 degrees), or did it instead do separate observations divided into smaller segments of the orbit that require only small adjustments for each, or something smarter? SamuelRiv (talk) 17:11, 7 August 2022 (UTC)
 * There's a good answer to this question here: . --Amble (talk) 19:27, 7 August 2022 (UTC)
 * It sort of gets to part of it. The HUDF is not in the CVZ, so I don't know if the 20-minute-average exposures were out of necessity for the orbit or for other practical reasons, but the Hubble Deep Field individual exposures seem to be (from the wording of the text) about 6 minutes, and that's in the CVZ. At the same time it quotes our article on the HUDF which cites NASA's press release for the Hubble taking 11.3 days of viewing time (exposure time) over the course of four months. So obviously they weren't just doing exposures for half an orbit and then waiting to come back around for another pass. Still, it doesn't answer what they actually do instead. SamuelRiv (talk) 20:59, 7 August 2022 (UTC)
 * You can find various types of historical Hubble scheduling here: . An example of a weekly timeline from 2003 including UDF observations is here: . It shows several UDF exposures of ~20 minutes each, within a time range, with other observing targets also overlapping that time range. Unfortunately, it doesn't seem to be as fine-grained as to say exactly when each observation began and ended. --Amble (talk) 05:03, 8 August 2022 (UTC)