Wikipedia:Reference desk/Archives/Science/2016 June 20

= June 20 =

Objections to “The Butterfly Effect”
What I find problematic with the notion of something like a butterfly flapping its wings and initiating major changes in, say, storm patterns is that while such an event is possible, it is very unlikely. Steve Baker, along with most commentators who use this example, seem to imply that every such small phenomenon leads to massive changes later on. The prime cinematic depiction of this notion can be found in the film Run Lola Run in which Lola runs on a desperate cause. Three variations of the run are shown (as if they were “sideways in time” to each other) and very small changes in the way events unfold have major changes in what eventuates. My problem with this lies in that I don’t think that our lives work like that. For example, for 12 years I lived in an apartment, and walked, shopped, ate out, took trains to the city and the beach, and so on. On some days, I would meet a friend and spend hours drinking and talking to them, on other days, I might forget something and have to go back home to retrieve an item. But each day, even if there were divergences, ended up pretty much the same. I came home and went to bed. Of course, there was an occasional event which DID change my life. On one occasion, I was invited to a party and there I got into a long and delightful conversation with a lovely lady who became my wife. Here was an example of a small deviation in my usual path which led to major changes. But here is the point: there were countless thousands of such small deviations from the normal, and none of the others led anywhere. If all or most of these changes DID lead to major changes, then I cannot even begin to see how my life, or anyone’s life, could begin to proceed. Every day would involve major departures from what had gone before. It would be like some kind of existential hurricane, with events thrown around so chaotically that nothing could make sense. A bit like some hyperkinetic music video.

So, I think that the “Butterfly Effect” can occur, but it is an exceptional event. Indeed, it is difficult to see how any meteorological phenomena could be predicted at all if it was infinitely sensitive to all such small events. For every butterfly who initiates a storm, there are billions of butterflies that do not, just as, in my own and your lives, there are millions of small events which do not affect our lives beyond their brief span. In the case of Run Lola Run, I have no problem with the idea that one such small change in the initial conditions could lead to major change in the outcome. What I find problematic is the clear inference in the film that ALL such small deviations will lead ineluctably to major qualitative changes in the outcome.

With regards to the scenario that an insect being clobbered in the past might lead to, say, lizard people dominating the future (so well-satirized by The Simpson's), well, I just don't buy it. Surely, there is a sturdier structure to evolution that would be not be vulnerable to every such small deviation. Perhaps, as in my own life, small deviations from the norm have effects which are visible for a while, but then, like ripples in a stream, become progressively weaker as time moves on - a case where some overcompassing logic of evolution makes itself felt. What say you? Myles325a (talk) 06:58, 20 June 2016 (UTC)


 * No. It is the sum of everything that occurs in the atmosphere that causes a hurricane in the far future. Millions of other butterflies each have the power to singlehandedly stop it or start it, delay it, advance it, move it left or move it right, make it weaker or stronger. If half the butterflies of Earth did the best possible things to stop New Orleans from being damaged in 2005 at a time when most of them could do it singlehandedly and half did the opposite, trying to hurt it and they all started and stopped intervening at exactly the same time I suppose they would balance out and nothing would change. I believe every time you burp the air movement causes many hurricane deaths many years from now and prevents an equal number. Theoretically you could even be simultaneously saving the same person from one hurricane and condemning him to death in another, all because of a burp. It's just random weather. But the random has to come from somewhere. Who knows where it ends. Maybe the chain of causation continues all the way down to quantum mechanical fluctuations, which would cause hurricanes but are utterly powerless to noticeably change any weather less than a certain amount of time in advance. Sagittarian Milky Way (talk) 09:27, 20 June 2016 (UTC)


 * I think you are confusing two different issues. The Butterfly effect is about the inter-connectedness of the the environment: comparatively small events in one place can start a series of events which result in much more dramatic events somewhere else. It should be seen as a metaphor, not as a literal description of the effect one butterfly can have.Most of what you are talking about concerns alternative realities: what might have happened if you, or anyone else, had done something slightly differently. The fact that you did things differently on different days is beside the point - what you have actually done is your actual reality. What your life might have been like if you had done something differently is the realm of alternate reality. What if your car had broken down and you had missed that party and never met your wife? What if the day you were late for work because you had to go back for something you forgot was the day your boss was deciding who to promote - and he picked someone else because you turned up late? Those things are unknowable - but make good fiction! Wymspen (talk) 10:22, 20 June 2016 (UTC)
 * Edward Lorenz coined the term Butterfly effect for the sensitive dependence on initial conditions in which a small change in one state of a deterministic nonlinear system can result in large differences in a later state. Chaos theory is the study of such sensitive systems. The OP raises a Straw man objection to Lorenz' observation by representing it as having real predictive power, saying this butterfly wing causes that hurricane. In reality chaos theory identifies many systems (including weather) where the consequences of even a tiny initial change can never be said to have finally played out. AllBestFaith (talk) 12:07, 20 June 2016 (UTC)


 * This popular fantasy seems like another way of saying "For Want of a Nail..." ←Baseball Bugs What's up, Doc? carrots→ 13:56, 20 June 2016 (UTC)


 * You're right, not every small change leads to big differences. But some can. And we can't know ahead of time which are which. What you're picking up on is the general stability of major ecosystems and human societies over scales roughly equal to human life spans. The funny thing about chaotic systems is that they can spend a very long time doing roughly the same types of things, and aren't very "random" at all. Keep in mind we are talking about deterministic chaos when we speak of the butterfly effect. I highly recommend this book, At home in the universe. It's ostensibly about abiogenesis, but a recurring theme is that life is sort of on the edge of chaos - too much chaos is too little conserved structure, and nothing can manage to reproduce. But too much stasis in a system makes it frozen and non-living. Anyway, it really is good, and touches upon some very relevant issues of what chaos means for biological systems.
 * Finally, keep in mind there are sort of different degrees of chaos. If the Lyapunov exponent is just barely above 1, then the system may look very regular and predictable, and may in fact be highly locally stable. But with a very large Lyapunov exponent, we get something like the hyperkinetic music video you describe. And all of this comes with a caveat based on mathematical models. All the top scientists agree that the weather systems are best modeled as chaotic. But the butterfly effect is technically a statement about a system of equation, not about the world. And the extent to which truths about equation are truths about the world is a tough topic in its own right ;) SemanticMantis (talk) 15:40, 20 June 2016 (UTC)


 * I think the idea is that you shouldn't ignore the thousands of small events. Almost all of them don't amount to anything, but if someone only looked at the "significant few" variables in your life, they could assume you're still single. 78.0.252.164 (talk) 13:20, 24 June 2016 (UTC)


 * Again these things can be analyzed it terms of precognition (aka mal de ojo, etc.); but again, the phenomenon is hazardous and not amenable to easy study. Any precognitive event can be viewed from two perspectives: precognition proper, when a memory of the future is accessed, and retrocognition, when that memory is stored in response to circumstance.  From the former point of view, information is gained but at the expense of possibly causing the event to come true; from the latter point of view, a strange thought is hallucinated directly into reality via a mechanism of prior recollection.  The frequency with which the phenomenon causes improbable results is at least indirectly a measure of the degree to which butterfly effect applies.  But it is difficult to really measure this.  For example, "how unusual" would be the death of Rick Rescorla or Elisabeth Targ, even if you think they were prec-related, which is also by no means sure?  Also, when manifesting this way, the butterfly effect is capable of something like a slingshot maneuver.  For example, suppose in 2000 you're looking at an old poster giving phonetic instructions to the Germans how to surrender, and you recall a terrorist shooting a machine gun in your direction while you laugh and unhurriedly run off yelling "Wir sorriender", which seems absurd and doesn't happen until years later when you go off into the woods a mile away from anyone in order to 'safely' fool around with precognitive phenomena without hurting anyone else.  After about ten seconds the firing starts up, the drunken sensation of retrocognition kicks in, you go have a look from a trail roughly downrange, etc.  But then you realize you crossed paths with them once maybe a month before when they were getting heavy cases out of their truck - presumably facilitating the precise "randomization" of the future event.  Meanwhile Chris Christie almost gets elected President... is that the butterfly effect?  More than chance, less than certain, perhaps. Wnt (talk) 17:10, 24 June 2016 (UTC)

Pompeii sink faucet
In old Pompeii main street one can see several ancient stone sinks, some of them ‘modernized’ with a new metal faucet. What is the correct archaeological term that describes such a process? Etan J. Tal(talk) 08:30, 20 June 2016 (UTC)


 * The words used by most archaeologists to describe such a practice would not be acceptable in print. Wymspen (talk) 09:20, 20 June 2016 (UTC)


 * Bastardized might be the word in question here. Pretty much the only acceptable case for adding modern materials to ancient objects is to preserve them, such as all the things done to the Leaning Tower of Pisa to prevent it from falling over. StuRat (talk) 15:02, 20 June 2016 (UTC)


 * The term is Renovation. -- Jayron 32 12:12, 20 June 2016 (UTC)


 * "Modernization" is an accurate term, but has a positive meaning. For a neutral or negative meaning, perhaps "altered" might be how an antiques dealer would describe it, or "married", in the case where 2 different items are combined, such as the ancient sink and modern faucet (Wiktionary lacks this def, so here's an article that uses it: ). StuRat (talk)


 * Retrofitting. Akld guy (talk) 19:16, 20 June 2016 (UTC)


 * Thank you for your cooperarion. Here is the photo with its present caption.

Etan J. Tal(talk) 05:58, 21 June 2016 (UTC)


 * 'Professional ignorance'? Etan J. Tal(talk) 06:24, 21 June 2016 (UTC)


 * Vandalism isn't the proper word, as that would mean it was done just to damage the object, while the purpose was to make it more useful, and the damage was incidental. I have seen the term misused in this way before though, such as when somebody spray paints "art" on a building without the owner's permission.  That may well be illegal, but it isn't vandalism, since their purpose was not to cause damage.  StuRat (talk) 13:47, 21 June 2016 (UTC)


 * Agree. Etan J. Tal(talk) 13:53, 21 June 2016 (UTC)
 * Faucetization--178.103.190.96 (talk) 04:23, 23 June 2016 (UTC)
 * What about "a tap on the head"? Alansplodge (talk) 14:17, 24 June 2016 (UTC)


 * Looks like a representation of the demigoddess Farrah. --107.15.152.93 (talk) 23:21, 24 June 2016 (UTC)

Fauna with High body temperature
Please any body tell me that what is the name of animal that has highest body temperature. please mention the temperature also. — Preceding unsigned comment added by Achyut Prashad Paudel (talk • contribs) 09:05, 20 June 2016 (UTC)
 * I'm not sure, but this will probably be one of the bird species, as their metabolism must be extremely fast in order to provide enough energy for flying. 67.164.54.236 (talk) 09:31, 20 June 2016 (UTC)
 * A 1991 paper states "The highest Tb [deep body temperature] ever recorded from a bird was 47.7C" DrChrissy (talk) 20:42, 20 June 2016 (UTC)
 * Look at bats too. Andy Dingley (talk) 11:34, 20 June 2016 (UTC)
 * Thanks for the prompt Andy. After making my comment about goats below, I had a quick look at bats (which of course are also mammals).  It appears they have a quite different approach to thermoregulation to other heterotherms.  Have a look at the abstract of this paper, particularly paragraph 6. DrChrissy (talk) 20:50, 20 June 2016 (UTC)
 * Not really my field anyway, but sorry for my rushed note this morning. AIUI, a simple statement "resting temperature and metabolic rate is dependent on the ambient temperature" doesn't hold true for the tree-roosting fruitbats anyway, as they are larger, have a rather different approach to thermoregulation from the smaller bats and their roost habitat is also more variable in temperature. Where I picked this up was in relation to the recent ebola epidemic, where the unusual metabolism and high temperature of bats was seen to be a significant factor (or maybe not). Andy Dingley (talk) 23:22, 20 June 2016 (UTC)
 * You didn't specify if you just mean warm-blooded animals (endotherms) or if animals who get their heat from the environment are also okay (ectotherms). The Pompeii worm is an animal that colonizes deep sea hydrothermal vents and comfortably lives at temperatures of 80 C.  Water bears (tardigrades) are claimed to be even more tolerant, and capable of surviving short exposures to temperatures up to 150 C, but those experiments are artificial and wouldn't constitute a natural living environment like we see with the worms.  Dragons flight (talk) 09:45, 20 June 2016 (UTC)
 * For warm blooded animals, can anyone beat the 116 F of the Scimitar-horned Oryx?--Phil Holmes (talk) 12:54, 20 June 2016 (UTC)
 * An even better question is, who inserted the rectal thermometer? μηδείς (talk) 20:15, 20 June 2016 (UTC)
 * Phil, I always thought that goats had the highest body temperature of the mammals, and sure enough, I trump your 37°C with 38.7°C. Before we get carried away with this, it is important to realise the site at which the body temperature is measured is terribly important; it varies by a surprising amount depending on the location. DrChrissy (talk) 20:30, 20 June 2016 (UTC)

Chemical Splitting of Methane gas
At what temperature Methane Splits into its constituent?(Say the lowest one) — Preceding unsigned comment added by Achyut Prashad Paudel (talk • contribs) 09:15, 20 June 2016 (UTC)
 * According to this paper, methane breaks down into hydrogen and acetylene at ~1230°C: 2CH4 → C2H2 + 3H2. (Note that elemental carbon is NOT produced in this reaction.) 67.164.54.236 (talk) 09:40, 20 June 2016 (UTC)

Refractometry
How do they measure the index of refraction (and the birefringence, if any) of opaque gems such as turquoise? Is there a special technique for this? 67.164.54.236 (talk) 09:29, 20 June 2016 (UTC)
 * The Refractive index $$n$$ of a material can be found by placing it in contact with a liquid of known lower refractive index and measuring the critical angle $$\theta_\mathrm{c} = \arcsin\!\left(\frac{n_2}{n_1}\right)\!$$. This needs only a very thin slice of a translucent gemstone and may also be done at non-visual wavelengths such as Infrared for which the material may be transparent. See Refractive index. AllBestFaith (talk) 11:32, 20 June 2016 (UTC)
 * Thanks! So they use a very thin slice to let the light through, right? 67.164.54.236 (talk) 22:03, 20 June 2016 (UTC)

Wheel bug nymph
In our article on wheel bugs, we give a photo of a wheel bug nymph with a red abdomen (and most other Google Image search pictures online show this too). However, the University of Kentucky's entomology website here shows the nymph having a white abdomen, which is the kind I have seen near my house (in Kentucky). Is this a particular subspecies or variety, or have we misidentified something else? shoy (reactions) 16:33, 20 June 2016 (UTC)


 * Yeah they usually/often have red abdomens, warning coloration I think. Then again there's lots of variation . I think this is within the range of within-species variation. The nymphs go through different instars, and the adults don't have red abdomens, so some instar should look like a nymph but have a less-red abdomen, right?
 * For greater certainty that actual wheel bug nymphs have red abdomens, see page 62 in this journal article that clearly describes them as having red abdomens. It is also possible that you are mis-identifying some other Hemipteran nymph - just recently I made the mistake of thinking some leaf-footed bug nymphs were assassin bugs :) I was not able to find any info on any recognized subspecies/varieties of wheel bugs, but I didn't try that hard. SemanticMantis (talk) 17:19, 20 June 2016 (UTC)

5 GHZ vs 2,4 GHZ wlan
if I use the 5 ghz is it more healthy because there is less radiation? If I use 5 ghz, does my mobile phone device has 0,00001% more power because it is easier for it to hold the wlan connection or does it use 0,000001% more power per day to be connected to the internet? --Ip80.123 (talk) 20:30, 20 June 2016 (UTC)
 * No non-thermal relationship between wireless electronic devices and health has been satisfactorily demonstrated -- if your phone's wifi antenna isn't hot enough to burn you, then it's not hurting you. No conceivable test could usefully distinguish a difference in cell phone power consumption on the order of 0.000001%. 5 GHz and 2.4 GHz bands are primarily distinguished by speed (5 GHz is faster) and range (2.4 GHz is available farther); those are the criteria you should be using to decide what you connect with. &mdash; Lomn 22:42, 20 June 2016 (UTC)


 * Although "less radiation" is very vague, a 5 GHz transmission has more energy per photon than a 2.4 GHz one, not that this has much practical significance unless you're designing hardware. --71.110.8.102 (talk) 02:42, 21 June 2016 (UTC)

Dear 71.110.8.102, are you sure with this proton theory? I have seen a youtube video where a guy has put his wlan router inside the microwave to see if there still comes the wlan signal out of it and the signal of the 5GHZ was from 100% down to 3% and the wlan of 2,4 has been lowered from 100% signal down to 20%, so it seems that the 2,4 is more powerful..--Ip80.123 (talk) 18:15, 21 June 2016 (UTC)


 * The higher the frequency the more it behaves like light. Less intrusion into objects, more coverage is based refexion and more locations of phase cancellation. -- Hans Haase (有问题吗) 19:37, 21 June 2016 (UTC)


 * Yes, this is Modern Physics 101. I provided a link to our article on photons, which explains this in depth. Radio waves can penetrate walls while visible light, which has a higher frequency, is blocked, which contradicts your assumption. This is a deep topic—trying to explain light's behavior was one of the primary motivations for the development of quantum mechanics—and there's plenty to dive into if you want to learn more. --71.110.8.102 (talk) 20:31, 21 June 2016 (UTC)


 * The behavior of microwaves and terahertz radiation can be surprising. Different frequencies penetrate materials differently.  There have actually been applications using terahertz to tell which bacteria are in the air (e.g. anthrax) based on absorption by their DNA.  And of course, absorption by their DNA should be of interest!  The radiation cannot break bonds, but can it displace a transcription factor with interesting effects?  I would guess it depends on the frequency. Wnt (talk) 00:19, 22 June 2016 (UTC)