Wikipedia:Reference desk/Archives/Science/2013 April 21

= April 21 =

life in space, literally
the previous question got me thinking; why do we assume, at least from the wikipedia articles i can find, that extraterrestrial biology will be planetary, or at least attached to things large enough to have gravity? I think most people would consider the possibility of planetary life evolving to live extraplanetarily, but given the presence of organic molecules in space, abundant energy sources, etc. would it not be at least possible that life could evolve out there? when you come down to it, planets aren't all that hospitable. there's no consistency to speak of: half the time there's no insolation, temperature fluctuates, chemical and mineral concentrations vary wildly over very short distances, etc. maybe some chunk of snow out in the oort cloud, or even less, would be enough for water based life, and maybe other bases would be happy out there as well? said organisms, ir any, would be behaviorally pretty well different from anything planetary, and maybe that explains the fermi paradox? Gzuckier (talk) 01:48, 21 April 2013 (UTC)


 * Good idea for a sci-fi novel, but not realistic -- depending on position in space, there's always either not enough light, or too much ionizing radiation, for life to survive in any conceivable form. Also, living cells need water (or another suitable liquid solvent), but no liquid can exist at the extreme low temperature and pressure found in outer space. 24.23.196.85 (talk) 02:27, 21 April 2013 (UTC)


 * Could you have liquid methane in space ? StuRat (talk) 04:55, 21 April 2013 (UTC)


 * Nope -- its triple point is well above the temperatures and pressures found in space. 24.23.196.85 (talk) 05:40, 21 April 2013 (UTC)


 * As far as sci-fi, reminds me of Larry Niven's The Integral Trees, in which, although a planet was involved, life thrived in a gas torus. I'm not sure how realistic the idea is though. Pfly (talk) 04:29, 21 April 2013 (UTC)
 * There's also Fred Hoyle's The Black Cloud, about a sentient cloud of gas that arrives in the Solar System. AndrewWTaylor (talk) 08:49, 21 April 2013 (UTC)
 * Isn't there a statistical argument for believing there are unlikely to be extremely big evolved beings? Something along the lines of the geometric mean of small and big (the size of the smallest particle and the universe) being a few metres which is the lengthscale of the most complex evolved systems (balance of permutation space of system versus number of permutations which can be tried in evolution)? --BozMo talk 20:22, 21 April 2013 (UTC)
 * The permutation argument looks bogus at best.
 * Let's look at a short piece of RNA, say of length 1000. That's 1000 4-way choices (2000 bits, ~10^600 possible combinations), or a 500-piece enzyme (500 20-way choices, although they aren't truly independent of each other - if they were,that would be ~10^650 possible combinations). What I'm saying is that there isn't that much matter in the observable universe to make that many combinations, and I wasn't talking about more than a single RNA strand and asingle enzyme respectively.
 * Could there be some kind of "living (reproducing) solar cells"? Some said there couldn't be, but didn't provide any reason. I'd think that they could take ionizing radiation quite well...
 * Any more ideas? - ¡Ouch! (hurt me / more pain) 08:20, 22 April 2013 (UTC)


 * I wouldn't mind hearing some more about the characteristics of very dilute gasses when viewed over very long timescales. We know that various "building blocks of life" exist in deep space, but of course they are exceedingly dilute.  Question is... if you look at a 10000:1 timelapse, do you start seeing path lengths and interactions that work at least a little bit like in aqueous solution?  Can the occasional stray photon of starlight kick molecules apart just often enough that despite the deep cold, they act more like a liquid over a long time scale?  But I'm not even sure how to properly frame the question, let alone answer it. Wnt (talk) 04:54, 23 April 2013 (UTC)


 * That would be a plasma (physics) then, but yes, cold plasma exists in space. Not sure if any level of self-organization can happen in there - it should be a long time anyway.
 * However, the thought that intelligent gas clouds can exist some 140 trillion years into the future (I'm running with Wnt's 10000:1 timescale) is quite fascinating. - ¡Ouch! (hurt me / more pain) 06:01, 23 April 2013 (UTC)


 * One "advantage" of space which was listed was a constant temperature, but, if a solid organism was near a star, the side near the star would be hot and the side away from the star would be cold. This could be remedied by a circulatory system to redistribute the heat, or, perhaps more efficiently, just by having the organism rotate so that a different side faces the star every few minutes.  So, if would somewhat become a mini-planet of it's own. StuRat (talk) 06:58, 23 April 2013 (UTC)
 * You're assuming they have to have a constant temperture. Larry Niven's outsiders (from the Known Space universe) generated energy by having one end of their bodies in light, the other in darkness, and taking energy from the heat difference (acting as a Heat engine) MChesterMC (talk) 09:58, 24 April 2013 (UTC)

Possible for a man to have kids without ejaculating?
Is it possible for a man to have kids without ejaculating? For example through direct extraction from the testicles. Pass a Method  talk  13:47, 21 April 2013 (UTC)


 * Yes. See Testicular sperm extraction.  Red Act (talk) 15:03, 21 April 2013 (UTC)


 * Also, there's cloning, which is possible from any cell with a complete set of DNA, although some cells are more suitable than others. (This has been done in animals, but hasn't been done in humans, because of ethical reasons, not technological limitations.)  StuRat (talk) 17:50, 21 April 2013 (UTC)


 * But don't you need a sperm cell and egg for fertilisation? I don't get this cloning thing. Pass a Method   talk  18:19, 21 April 2013 (UTC)
 * The DNA present in any cell of any animal is essentially the same DNA (barring cell division mishaps, radiation damage, mosaicism, etc) and it is complete. There is a complex mechanism that determines which parts of the DNA are "switched on" or in active use during the development from egg to complete adult animal.  Therefore, in theory, any human can be cloned by taking any cell from them, and manipulating the cellular mechanisms in that cell to turn it into a functioning fertilised egg.  At presnt, how to do this is not fully understood, so cloning of mammals is done using stem cells, but in theory any cell can be used as the starting point. Wickwack 124.178.133.119 (talk) 00:51, 22 April 2013 (UTC)
 * Cloning basically skips over the separation of gametes and the union of sperm and egg. But there is a semantic question of whether it would count as 'having kids'.  I can picture the courts we have saying that no matter what extraction was used on you you're on the hook for the child support if they steal sperm from the testes, but technically a clone is more like an identical twin than an offspring.
 * Nonetheless, there's a way around it... take germ cells from the clone and implant them in a mouse testis or something, and isolate sperm cells from that. Wnt (talk) 04:58, 23 April 2013 (UTC)


 * They do need a host cell, which is typically an embryo from which they've removed the DNA. They then place the DNA they want to clone inside the cell nucleus.  Read our article (I linked to it above) for more details.  StuRat (talk) 18:22, 21 April 2013 (UTC)
 * Though perhaps obvious, given the way the question was posed it is important to note that pre-ejaculate can contain sperm (e.g. from a recent ejaculation) - one of the reasons that adherents of the withdrawal method of contraception are often also known as "parents". -- Scray (talk) 22:12, 21 April 2013 (UTC)

Chemistry for kids
I have a bright and inquisitive ten year old at home. Among the dozen or so careers she's got on the back-burner (inc. archaeologist, medical examiner, surgeon, history teacher, and journalist...) is chemist. Since that's the ascendant one at the moment, I'd like to nurture it. At the moment, she's trying to extract dye from a solution of wild berries :-). Anyway, there are approximately ten million websites and books out there that purport to be for kids - even narrowing it down to chemistry still leaves a boggling number to go through. Does anyone have any specific recommendations they could suggest? I would also be open to purchasing some equipment or materials off the internet if necessary, though my experience there is that such things are either extremely expensive or utterly pathetic. Alternately, some suggestions as to what to do with about 300 mL of berry juice fermenting on my windowsill may also come in handy. :-) Matt Deres (talk) 21:01, 21 April 2013 (UTC)


 * Red cabbage juice makes a good acid-base indicator. Boil red cabbage, decant off the juice, and you can make a pretty good pH reading of any added solution by the color.  See the Wikipedia article on Red cabbage.  Broadly speaking "Kitchen Chemistry" is the Chemical educator's term for these sort of home-brew experiments.  Mentos & Diet Coke is another classic, one can discuss issues like nucleation and gas laws and all sorts of things from that basic experiment.  M&M Chromatography is another good one.  A coffee filter, a toothpick, and a bag of M&Ms is all you need, and you can get a nice discussion of mixtures vs. pure substances out of that one.  This website has all of those, and more, and they all look pretty easy to do, most of them have stuff that you have around the house, or at worst a trip to the corner store.  -- Jayron  32  00:26, 22 April 2013 (UTC)


 * First of all, I congratulate both you and your daughter. The vast bulk of kids these days are just not interested in doing their own science, and most parents don't want them to.  When my generation were kids (1950's), it was quite the normal thing for us to have a shed in the backyard, or a room in the house as our "laboratory".  I had one, about 3 or 4 other school friends did as well.  Of course, being boys in the 1950's, making explosives and rocket fuel out of household materials had a high priority.  Back then it was accepted that the occasional mishap would occur and was part of growing up.  Nowadays, such a thing is just not done, and parents seem to want to completely structure their kid's days while keeping them in cotton wool - the result is a lot of dumb kids who don't ever ask "why is it so?"
 * If she is a really bright kid, I suggest getting the Scientific American Amateur Scientist DVD, which has a multitude of experiments that are 1) easy to do at home; 2) will take her to a quite advanced level in science; 3) uses things you can easily buy at minimal cost; and 4) has about the right balance between inherent safety and teaching her to work with safety in mind, so that if/when she progresses to devising her own experiments, she will have the right mental discipline built in. Most of the experiments are designed for those of teeeage years and up, but a bright 10 year opld that can read well will cope just fine.
 * Wickwack 124.178.133.119 (talk) 01:03, 22 April 2013 (UTC)


 * Matt, if you really have 300 ml of berry juice fermenting, you could use that to teach your daughter about wild yeast. I wouldn't suggest getting her drunk on the result though!--TammyMoet (talk) 12:22, 22 April 2013 (UTC)


 * If your daughter wants to be a professional scientist, I'd say the most important thing is not the experiments (anything is educational, so long as it's fun!) but developing her use of the Scientific method. For a 10-year-old, this can be boiled down to 'Plan-Do-Review'. So, for instance, if you want to try the classic Diet Coke and Mentos eruption experiment (WARNING: Do it outside!) then you might have a conversation like this:
 * MattDeres: "What do you think would happen if we dropped some Mentos into this bottle of Diet Coke?"
 * LittleMissDeres: "Erm, dunno. Would it taste minty?" (Plan)
 * MattDeres: "Well, let's see." (Do)
 * LittleMissDeres: "Woah!"
 * MattDeres: "Ok, so why do you think that happened?"
 * LittleMissDeres: "The Mentos started to fizz and that made the Coke erupt out of the bottle." (Review)
 * MattDeres: "Exactly. But maybe we should see what it is about the Mentos that makes them do that. How could we do that?"
 * LittleMissDeres: "By trying other sweets? We could try other minty sweets that are made of different things, and sweets made of the same things but with different flavours to find out whether it's the flavour or the ingredients." (Plan)
 * And so on and so forth... - Cucumber Mike (talk) 13:22, 22 April 2013 (UTC)


 * Her interest in extracting the pigment is commendable, and shouldn't be shunted off into the same showy experiments all the other kids do. The key thing here is that she is probably unknowingly trying to reinvent basic biochemistry techniques like solvent extraction or chromatography, and you should try to get ahead of her so you can improve her luck.  First, let's find out what kind of berries they are, and exactly what the pigment is.  Can we extract it with a nonpolar solvent (mineral oil) or something less so (alcohol)?  Is there a chance it's an alkaloid that can be manipulated by acid-base shifts?  Can it be separated out by thin layer chromatography?  It might be a fun game to first look up possibilities for her, talk her through a simple experiment, then explain the concepts (or have her read up on them and explain them to you? B) ). Wnt (talk) 14:57, 22 April 2013 (UTC)


 * Once she has the pigment extracted, I suggest she use it to write her name on a white cotton T-shirt, using a fine brush. This will give her a permanent souvenir of her experiment. StuRat (talk) 05:18, 23 April 2013 (UTC)

Thanks for the replies everyone; I've got some stuff to look up, it seems. I've got a degree in archaeology and can talk basic physics and evolution with 'most anyone, but chemistry has never been my strong suit. @Wickwack: I'm having trouble finding the DVD you mentioned - are you sure you got the name right? Amazon has no hits and the closest hit is a $1,200 (!) book collection. My uncle, from whom I got my interest in science, was one of those kids blowing stuff up back in the 1950s. Trying that these days is a good way to end up in a whole heap of trouble, though. @Cucumber Mike: She has a basic understanding of the general purpose of the scientific method (hypothesize - get grant money - test - publish :-); from what I gather, it's standard on public elementary school curricula here (SW Ontario). @Wnt - getting the kid to explain things to the grown up is the first trick any parent learns. "Uh, yeah, that's it. Good job. Just... testing." Next week is her first try at an adult public lecture at Perimeter; just my luck she'll fall in love with calculus - one of the few things I'm worse at than chemistry. :-/ Matt Deres (talk) 00:04, 24 April 2013 (UTC)
 * The Amateur Scientist DVD was published in 2004 as The Amateur Scientist 2.0 The Complete Collection Version 2.0 Science Fair Edition, and advertised in various hobby, electronics, and other magazines, typically for $49. A similar edition was advertised by Scientific American magazine, however upon checking they are no longer advertising. I will investigated further. Wickwack 120.145.21.97 (talk) 10:07, 24 April 2013 (UTC)
 * If you come back to us with what the berries are (or at least a picture of the source bush) you might not have to do the chemistry alone. (If some people get on this it might even become a Wikiversity content item) Wnt (talk) 13:59, 24 April 2013 (UTC)
 * Apparently, they were cranberries the wife had thrown out back earlier for the birds (who had no use for them). Matt Deres (talk) 22:36, 24 April 2013 (UTC)

Can a female athlete get back in full shape 2-months after birth?
Is it possible for a professional female track athlete to get back in full shape 2 month after giving birth? I mean endurance sports such as running. Pass a Method  talk  22:08, 21 April 2013 (UTC)
 * It seems unlikely to me, but every person is different. Among other concerns would be whether the cartilage has had time to tighten back up again (see here and here for example). Anyone attempting such a thing would definitely need some extensive dialogue with a physician or obstetrician. Matt Deres (talk) 22:18, 21 April 2013 (UTC)


 * Liz McColgan won a bronze medal at the 1991 IAAF World Cross Country Championships four months after giving birth (ref). -- Finlay McWalterჷTalk 22:40, 21 April 2013 (UTC)


 * There are many stories of female athletes deliberately timing a pregnancy before a major event like the olympics precisely in order to use the hormonal changes to improve their performance. This, for example says that the benefits are such that women who have just given birth are able to start training soon after and that they gain significant benefits in events between 2 and 10 weeks afterwards.  I'm not sure how soon before the event this would have to take place - but far from being "out of shape", they evidently believe that they'll be in better than "normal" shape...almost akin to taking performance-enhancing drugs - but doing it naturally, and therefore legally. This article discusses some of the issues.


 * See also Abortion doping - which is the shadier side of that.
 * SteveBaker (talk) 02:50, 22 April 2013 (UTC)