Wikipedia:Reference desk/Archives/Science/2015 December 3

= December 3 =

Has the density of the Universe ever been greater than 1.0?
In Planck units, how could you ever have a Planck density greater than 1.0?

That completely fills the Holographic principle leaving no room for any other information. Any history before that moment would be crowded out.

Ergo the Universe didn't start with infinite density, just density 1.0 or less. Hcobb (talk) 00:16, 3 December 2015 (UTC)


 * Our article on this is Planck epoch. Graeme Bartlett (talk) 21:55, 3 December 2015 (UTC)

Gay Bomb
Gay_bomb page has some abuse on it. Im very poor at wikipedia, can someone try to fix the page. --84.248.87.146 (talk) 09:42, 3 December 2015 (UTC)


 * I've reverted some recent vandalism. Clarityfiend (talk) 10:12, 3 December 2015 (UTC)

Masturbation for Astronaughts
I'm not going to to lie, but every man I've ever known (including myself) really needs to ejaculate at least once or twice a week. Trying to hold back the urge for more than two weeks is a nightmare. And with most missions lasting months, what are astronaughts meant to do about it? Is there any sort of training their given. Anti-libido pills? Some kind of sock? I mean, in low gravity, the stuff would go everywhere especially if you've got a crew of many men. The risks would be immense but you can't ignore natures call?? — Preceding unsigned comment added by 210.216.57.223 (talk) 15:21, 3 December 2015 (UTC)


 * I want to answer this, but I keep giggling to the tune of On the Beautiful Blue Danube and trying to work out the zero-gee mechanics... give me a minute. Wnt (talk) 15:30, 3 December 2015 (UTC)
 * I'm not sure this is a legit reference, but it's a start... Wnt (talk) 15:33, 3 December 2015 (UTC)


 * Just waiting for the defacto RD police "M + BB" to shut this question down and cry "troll". — Preceding unsigned comment added by 92.241.130.120 (talk) 15:39, 3 December 2015 (UTC)


 * Nay, you should research and post something relevant if you find it. "Enjoy yourselves. Tomorrow it'll be a ruin." Wnt (talk) 15:49, 3 December 2015 (UTC)
 * See Reference desk/Archives/Science/2012 December 11 - it didn't end well, but the question has been addressed before. "Astronaut", from the Latin nauta, incidentally. Tevildo (talk) 20:37, 3 December 2015 (UTC)
 * Astronaut says: The term derives from the Greek words ástron (ἄστρον), meaning "star", and nautes (ναύτης), meaning "sailor". But no human has ever been anywhere near a star, or has ever even tried. Maybe they should be called lunonauts, selenonauts, or planetonauts. --   Jack of Oz   [pleasantries]  04:19, 4 December 2015 (UTC)
 * Maybe the OP is thinking of "astronaughty bits". ←Baseball Bugs What's up, Doc? carrots→ 06:02, 4 December 2015 (UTC)
 * By the way, the Apollo 12 flight journal linked from that old posting would now be here. Well, I was curious. --76.69.45.64 (talk) 17:27, 4 December 2015 (UTC)
 * Survival trumps frivolity. ←Baseball Bugs What's up, Doc? carrots→ 18:17, 4 December 2015 (UTC)


 * Here is a link to masturbation for editorial convenience. μηδείς (talk) 23:11, 4 December 2015 (UTC)

Stages of non-grief emotions
Is there any counterpart to the Kübler-Ross model for emotions other than grief, that would analyze them in specific stages?

I'm specifically curious because I feel like stages of, I dunno, "suspicion" seem closely allied to the scientific method. For example, suppose you think you hear a funny noise from the furnace. Well, first you just make a note of it in case it happens again ... then you're listening for it intently ... then you start hypothesizing about what is wrong ... then testing if it is in fact not working. Or some such thing. It seems like that's not that different from some of the stages of grief like denial and bargaining, and of course the furnace problem can have some anger, resignation, even fear involved also. But if that were true, it would mean the scientific method is instinct, something bred into the limbic system, rather than a technological achievement at any time in recent history. Anyway ... has such a generalization ever been attempted? Wnt (talk) 15:56, 3 December 2015 (UTC)


 * I'd just like to note that this is a very interesting question. I realize that although I do this all the time, I have never thought of it as a thing. Thanks User:Wnt. μηδείς (talk) 01:29, 4 December 2015 (UTC)


 * Have a look at abductive reasoning, and this paper, particularly the bits (p.378) where they cite Charles Sanders Peirce as well as some work from this century. The Carruthers (2002) paper I think will be worth a look regarding the potential for an innate/instinctual human tendency that is rather similar to the scientific method. SemanticMantis (talk) 19:26, 3 December 2015 (UTC)


 * I found that here, but ... well, at least at first glance I'm having a hard time doing anything with it. He's looking at it from a different perspective, or maybe I'm just not giving him a chance.
 * For one thing, I'm thinking at the moment of something much more general. For example, some dating service used to advertise with "First Comes Like", capitalizing on the notion that people accept that love goes through a series of stages which, again, don't seem all that dissimilar from those of grief or scientific method in concept.  Fear on the other hand is maybe a bit of an outlier in that it tends to go straight to full mast, but even it can start slowly under the right circumstance ... though maybe it can be regarded a stage of something else, like fight-or-flight?  I feel like there ought to be some kind of unifying architecture underlying all emotions, of which scientific curiosity is one. Wnt (talk) 20:04, 3 December 2015 (UTC)
 * For what it's worth, I should note it is possible to look up a great number of articles that talk about stages of falling in love. Since grief and love are practically the same emotion anyway, save for circumstance, trying to place a chart from this beginning may help to clarify my thoughts.  Though what they have in common is (not so surprisingly) limited, there are some commonalities we might expect: people are infatuated at the beginning, make decisions in the middle, and become more comfortable or habituated later on.  (quoted terms are from ):

Something that pops out as I try to draw up the chart is that I'd think the "bargaining" stage might have two substages - one in which a person tries to find out as much as possible about the disease, and another where they say I hope it's only that, maybe I can stop it here etc. I wonder if there's anything in favor of that. Wnt (talk) 04:19, 6 December 2015 (UTC)

Are Modal Realism and the Mathematical Universe Hypothesis the same thing?
Hi,

I mean ontologically: obviously the two ideas are motivated very differently and purport to explain extremely different phenomena, but they seem to be in very much the same ballpark in the kinds of things they describe as existing. To put the question another way, are there possible worlds which a modal realist believes in but not a MUH-er, or vice versa?

Thanks much in advance, helpful internet people :) Dan Hartas (talk) 17:13, 3 December 2015 (UTC)


 * I think you're on to something. Tegmark's key paper is here, and he says that his intent is to cast... the so-called modal realism theory of David Lewis in mathematical terms, akin to what Barrow refers to as “π in the sky”
 * The sentence contains inline citations that I've omitted for clarity, but they will probably help anyone who doesn't know what Barrow is was talking about. The full context is on p. 16 and the first hit for "modal" in the article. That being said, I suppose it's possible that some adherent of modal realism (person A) disagrees that Tegmark has succeeded in his self-claimed goal, and A may well believe in some possible world that Tegmark does not. Possible world semantics are, as you likely know, a bit of a pain :) SemanticMantis (talk) 18:40, 3 December 2015 (UTC)

Fake snow that feels liquidy but no apparent moisture on your hand?
Is there a type of fake snow that feels liquidy but leaves no apparent moisture or wetness on your hand? Also, it does not melt on your hand. Natural snow feels icy cold and uncomfortable, but this unknown material feels like some kind of liquidy, moist, cool substance. 140.254.136.161 (talk) 19:27, 3 December 2015 (UTC)
 * Whatever it is, is this thing even biodegradable? What happens if birds accidentally eat this stuff? Will they be poisoned? Will they choke? 140.254.136.161 (talk) 19:28, 3 December 2015 (UTC)
 * Dry ice works this way - I suppose if powdered "just the right way", you might compensate for the increased surface area (which tends to freeze you quickly) with a general "fluffiness", which would be more insulating. But when dry ice I've seen seems snowiest I think you've just let it get moisture into it, and that bit is wet on evaporating.  Are there other non-toxic gases that freeze at a higher temperature and have no liquid phase at standard pressure? Wnt (talk) 20:08, 3 December 2015 (UTC)
 * However, dry ice sublimes at −78.5 °C (−109.3 °F) - this is cold enough to cause nasty frostbite burns. You don't want to get that one your hand! Smurrayinchester 22:26, 3 December 2015 (UTC)
 * I've held enough of that in my hand not to be excessively concerned... it can be colder if powdered - the thing is, usually powdering it makes it like sand. If there were a way to powder it into "fluffy clumps", some kind of filaments of dry ice on the microscopic level I suppose, it might not seem very cold at all.  (I don't know, would be interesting to see)  It only really gets nasty if you wet it with ethanol or something.  By and large the exposed metal in a -80 C freezer is worse, and who really wears gloves to reach into one of those?  (Unless it's to protect their precious RNA samples, that is) Wnt (talk) 16:04, 4 December 2015 (UTC)
 * Our article on triple point lists acetylene as another with triple point above 1 atm, but it freezes actually at a lower temperature than CO2. I looked for some other alkynes but it looks like they get alkane-like, with low BPs and a liquid phase.  I'm not really sure how to hunt through data for all known chemicals to find one with a triple point around 300 K and >1 atm. Wnt (talk) 20:22, 3 December 2015 (UTC)
 * You're probably thinking of Sodium polyacrylate - a common chemical for artificial snow that holds water very effectively so it feels cold and wet, but doesn't leave any noticeable liquid behind. Smurrayinchester 22:26, 3 December 2015 (UTC)

Why do real flowers feel so soft on the fingers?
Fake flowers feel stiff and papery. Real flowers feel so soft and smooth, and when you rub on the petals or the leaves, they feel moist. 140.254.136.161 (talk) 19:31, 3 December 2015 (UTC)


 * Expensive fake flowers are made of silk, cheap fake flowers made of polyester. More info at Artificial_flower. Both of those are rather different from the living cells that make up a flower petal. The gross surface structure is called the Plant_cuticle, and it can vary quite a bit across different flower types. Petals are really just specialized leaves, and the soft, velvety texture of e.g. a rose petal is in part due to its roughness at a very fine scale. This is the same reason that velvet feels softer than paper. This roughness makes the petal hydrophobic, and helps keeps the petals clear of dust and debris (so as to remain most visible to pollinators). Some info on this can be seen at Wetting. The Lotus_effect is a bit different, but related, and that article is much better. Here's some recent popsci coverage as well. SemanticMantis (talk) 19:46, 3 December 2015 (UTC)
 * Some real flowers don't feel stiff and papery. Try Dipsacus or Xerochrysum bracteatum. Similarly some leaves of flowers don't feel soft and smooth, try Symphytum or Stinging nettle if you have those plants in your part of Ohio. Richard Avery (talk) 07:59, 4 December 2015 (UTC)
 * I think you meant some real flowers do feel stiff and papery, and that's a good point too. SemanticMantis (talk) 14:32, 4 December 2015 (UTC)


 * Doh!! Thanks SM.Richard Avery (talk) 16:00, 7 December 2015 (UTC)

Will water-based personal lubricants work for non-sexual purposes?
I found water-based personal lubricants at home. I know some people use them for sex. But will they work for non-sexual purposes too? Can I use it to clean the table? Will it work? 140.254.136.161 (talk) 19:40, 3 December 2015 (UTC)
 * It's a lubricant, not a soap or detergent. I don't know that it would clean your table so much as make it kind of greasy feeling.  Many water-based lubricants become tacky as they dry out.  -- Jayron 32 19:51, 3 December 2015 (UTC)
 * What do you mean by "tacky"? 140.254.136.161 (talk) 20:02, 3 December 2015 (UTC)
 * Definition 1 here. -- Jayron 32 20:17, 3 December 2015 (UTC)
 * Wouldn't #2 do nicely also? :) Bottom line though ... give us the ingredients or at least the brand name, otherwise it's pointless to guess. Wnt (talk) 20:24, 3 December 2015 (UTC)
 * The major brands and generics of such personal lubricants have roughly the same ingredients, in subtly different proportions. The main ingredients are usually polyols of some sort (glycerin or propylene glycol or sorbitol or xylitol) which provides the lubrication, and the "jelly" forms also have thickeners such as alkoxy-cellulose.  The viscosity is controlled by the amount of water in the system; and as they dry, they become more viscous.  -- Jayron 32 20:34, 3 December 2015 (UTC)
 * I'm still struggling with why you'd want to use lube of any kind to clean your table. There are oils that get used for furniture polish, but they're not there to clean and they're not really lubricants (or at least would rarely get used as such). Generally speaking you need to be careful when switching lubricants of any kind as there are many different kinds with a wide variety of appropriate uses (a famous example is that many petroleum based ones degrade latex, so are unsafe for people using condoms) . Our article at lubricant gives an idea of the complexity, but could really use some work. 64.235.97.146 (talk) 21:00, 3 December 2015 (UTC)
 * Part of the confusion may be because the only real difference between, say, liquid hand soap and KY Jelly is a detergent or soap compound like sodium stearate. In other words, if you take KY Jelly and mix in sodium stearate, you basically create liquid hand soap.  They often feel the same to ones hands (which aren't terribly sensitive), and people may wonder why liquid hand soap cleans, why KY Jelly does not.  The difference is in the sodium stearate, which is the soap part.  -- Jayron 32 21:04, 3 December 2015 (UTC)
 * Furniture "cleaner" may work on different principles than soap... people use all sorts of furniture polish. Someone online promotes using a mix of oil, vinegar, and glycerin  and from the comment above this might (or might not) contain glycerin.  This is art not science - I assume you're balancing what it does to clean, how glossy it looks, how stable it is over time, if it attracts dust, how it smells, God knows what.  Maybe someone is thinking of how it might feel on a certain person's bare bottom... :)  I don't know.  But what I do know is that we're not giving professional advice here, or any sort of advice, and if you mess up a $3000 table our liability is still limited to $0.000000000000001 or less.  Also, all legal actions should be settled by a private arbitration action before the Caliph Abu Bakr al-Baghdadi; the party suing should travel to him first to lay out the case; we should be along in a week or two afterward to hear the verdict. :) (This is actually a totally legal term of service to include in a product insert in the U.S., AFAIK!) Wnt (talk) 22:18, 3 December 2015 (UTC)
 * The vinegar in that case is the key ingredient; while many cleaners and the like are based on base chemistry (see saponification for all the gory details), acid-based cleaners are also well known, classically Pine Sol is based on a phenol-based solution, which provides acid, rather than base, chemistry for the cleaning. Vinegar (acid) generally works about as well as ammonia (base) as a cleaner as well.  The glycerin in these cases is almost always there as a humectant, that is it is used as a treatment to keep the wood moist.  Glycerin, like many polyols, is hygroscopic.  In the case of your furniture polish the vinegar cleans, the glycerin retains moisture, and the oil seals the surface.  -- Jayron 32 02:42, 4 December 2015 (UTC)
 * See Preston v. Ferrer and AT&T Mobility LLC v. Concepcion. Not that _this_ should be constituted legal advice, either. Tevildo (talk) 22:44, 3 December 2015 (UTC)

Disasters / International space station
Is there any procedure in place for the crew of the ISS if matters took a turn for the worse here on earth. Say, a full scale nuclear exchange resulting in the destruction of any sort of civilization. Let alone the means to rescue the Soyuz capsule.

I mean, what would they do. Cyanide pills? Sit it out and starve / run out of oxygen? — Preceding unsigned comment added by 213.202.212.178 (talk) 22:53, 3 December 2015 (UTC)


 * At any time, the ISS has Soyuz capsules already attached with enough capacity (and comfy personalised moulded seat linings) to return the entire crew to Earth without outside intervention. A Soyuz can have a rather bumpy landing (sometimes very bumpy) and usually landing crews wait inside the capsule for the ground folks to show up to help them. But it's always been considered possible that, in some exigent circumstance, they might end up having to leave the capsule unaided and fend for themselves in the central asian wilds (see TP-82, and this article). -- Finlay McWalterᚠTalk 23:02, 3 December 2015 (UTC)


 * Without assistance from earth, ISS is doomed. If there is a full scale nuclear exchange resulting in the destruction of any sort of civilization on earth then ISS is doomed. The best option for crew of ISS to survive long term is to escape down to earth and play real life Fallout 4. 175.45.116.61 (talk) 00:49, 4 December 2015 (UTC)
 * Excuse my cynicism but if there was a full scale nuclear exchange which destroyed any sort of civilisation on earth why would the members of the ISS attract any special consideration above the rest of humankind. Richard Avery (talk) 07:45, 4 December 2015 (UTC)
 * I'm really amazed to hear about the guns, but I still think cyanide pills would be a really unlikely idea. I mean, think about how liquids act in zero G, worming their way into things... and what potassium cyanide does when it touches water.  Hard to open a window to fan out the fumes! Wnt (talk) 18:56, 4 December 2015 (UTC)
 * And as long as we're being morbid, cyanide poisoning is a painful and terrifying way to die. It isn't pretty. If the crew wanted to commit suicide easily and painlessly, they'd just vent the station. Hypoxia is painless. Air hunger is caused not by lack of oxygen, but high blood levels of carbon dioxide. --71.119.131.184 (talk) 21:55, 4 December 2015 (UTC)


 * There was a story on the radio recently about a situation where a bad software patch was sent to the ISS and crashed their computers. It also took out almost all communications with the ground.  The comment they made on this was that the lack of ground communication was deeply concerning because any fault conditions that crop up on the ISS have to be fixed in consultation with the ground crew.   So I think the ISS would only survive until the next significant equipment failure.  Even if they had spare parts on hand, all of the expertise needed to diagnose the fault and relay instructions on how to fix the problem lies in the hands of the ground crew.  Failures of one system or another are fairly common up there - so I think their lives aboard would be pretty short.  When this problem occurred with the computers - the first instruction was "go find the emergency backup radios and ask for help".  Since other "failure modes" are largely handled on the ground - it's rather unlikely that this one extreme situation would be provided for in flight crew training.  Besides, there are multiple ground stations - and it's hard to come up with ANY scenarios where life on earth would be wiped out so rapidly that instructions could not be radioed to the ISS to tell them what (if anything) they should do. SteveBaker (talk) 20:15, 4 December 2015 (UTC)


 * It's my understanding that, if they really have to, the ISS crew can operate it autonomously, but (because it's arguably the most expensive self-contained object ever made by mankind) they're loath to do so without many terrestrial boffins to check the maths. The limits to the ISS' untended endurance are twofold - consumables for the crew and kinetic energy. The longest the ISS has gone without a resupply is about 120 days; maybe with eating through the emergency rations and stuff they can eke it out to 180 days. Secondly is KE - the ISS is gradually slowed down by the drag of the thermosphere on it, causing it to lose altitude all the time (graph).  In normal operation it receives a periodic reboost from the visiting Progress craft; absent them, the Zvezda module has 2 altitude thrusters and a reasonable supply of fuel (860 kg of unsymmetrical dimethylhydrazine and its hypergolic oxidiser nitrogen tetroxide), which can reboost for a while (I don't know whether the ISS usually has a radar altimeter necessary to know quite how high they are - but I guess with a stopwatch and sextant, and some identifiable marks on the ground, the crew can figure that out for themselves). That 180 days or so gives them time to select a landing area (they're going to want to aim for the centre of a continent) and maybe wait for the wait for the weather there to be okay (it'd be tough to survive unsupported on the Kazakh steppe in February), and if the calamity is nuclear or biological then it may be wise to try to wait out the worse short-lived radioisotopes or the peak of the plague.  If they landed in western Kazakhstan in May, with the Soyuz packed with tools and supplies (rather than the usual science experiments and bags of poo it usually carries back from space) 180 days after Judgement Day, they'd probably be much better off than all of us. -- Finlay McWalterᚠTalk 01:02, 5 December 2015 (UTC)