Wikipedia:Reference desk/Archives/Science/2014 May 2

Science desk
< May 1	<< Apr | May | Jun >>	May 3 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

May 2

Did the Inflationary epoch create time?

As we all know, the arrow of time is driven by the growing spread of quantum entanglement. Since any Cosmic egg would be fully entangled, it would be a state where no forward motion in time could occur.

Ergo it was the Inflationary epoch when the universe got dis-entangled that laid the groundwork for Entropy's clock, and no time could have occurred during any previous hypothetical fully connected phase.

Hcobb (talk) 03:55, 2 May 2014 (UTC)

We do? It was? Eh? It would? I don't see that at all, however using Paradoxes of material implication I think I would have to agree that your conclusion does follow your premises. Dmcq (talk) 09:07, 2 May 2014 (UTC)

You don't really seem to be asking a question here, but rather trying to persuade us of a handful of highly questionable cosmological claims. AlexTiefling (talk) 09:14, 2 May 2014 (UTC)

The arrow of time article doesn't mention the word "entanglement". However, entanglement does mention this idea, citing [1]. Unfortunately, I don't think I know anything about quantum physics that isn't in Wikipedia, and half of that people will say is wrong when it's discussed here. Wnt (talk) 12:05, 2 May 2014 (UTC)

If we've got it wrong let's straighten it out, but it's the first solidish looking theory anybody's had to explain where time comes from.

Perception of time => Entropy => Quantum entanglement => Initial non-entangled state.

Hcobb (talk) 12:31, 2 May 2014 (UTC)

You're second => does not follow, really. Also, your initial question treats time as a "substance" It isn't. --Jayron32 12:34, 2 May 2014 (UTC)

You're clearly not the first person to propose a theory of time. Don't give yourself airs. Come back when you've spotted the contradiction in your original proposal. AlexTiefling (talk) 12:43, 2 May 2014 (UTC)

No, don't come back, unless you have a question to ask. This is not a place for debating issues or propounding theories, and the above editors should not have engaged the OP. -- Jack of Oz ^{[pleasantries]} 12:48, 2 May 2014 (UTC)

Did been in a time of a virtual realism a time been during as in a real time?--Alex Sazonov (talk) 12:50, 2 May 2014 (UTC)

Huh? What is the Russian text for your question? It makes no sense in English. Edison (talk) 13:36, 2 May 2014 (UTC)

It doesn't in Russian either, remember? InedibleHulk (talk) 02:28, 4 May 2014 (UTC)

I don't think the problems mentioned here are going to be solved this way. Count Iblis (talk) 18:05, 2 May 2014 (UTC)

Did been in a time of a virtual realism had been a time distortion or it been only in a real time?--Alex Sazonov (talk) 06:06, 3 May 2014 (UTC)

Backup CF card

When travelling, I used to back up pictures from a CF card to a portable hard disk like this one. This worked perfectly also in remote places. Now I am planning a trip to a country where there is free wifi at every corner (or at least at any hotel) and I was wondering whether there is a better (smaller/fail proof) solution that allows me to upload the pictures to a server (e.g. my own server). Maybe something that connects to a smartphone or a standalone wifi/card-reader device? bamse (talk) 09:19, 2 May 2014 (UTC)

If your phone has USB OTG you may be able to just plug your CF card into a cheap USB CF card reader, then plug the card reader into the phone. Main issue is whether the card consumes more power than the phone can supply. This question should actually be on the computer reference desk, by the way. 70.36.142.114 (talk) 14:02, 2 May 2014 (UTC)

Water in solar system planets

If some comets are made up of water, and if they collide with planets every now and then, isn't it obvious that at some time they have collided against any planet in the solar system and therefore, there is water in any of them? Maybe the smallish monds won't have enough gravity to keep it, but how could giants as Jupiter or Mars lose it? OsmanRF34 (talk) 13:26, 2 May 2014 (UTC)

Indeed, there's plenty of water on both Jupiter and Mars (Frank Sinatra singing in my head there...). I might be wrong, but I don't think there's a single planet or minor planet that has been shown to be entirely devoid of water. Fgf10 (talk) 13:32, 2 May 2014 (UTC)

I thought it was considered surprising when water was discovered on earth's moon. Of course water-bearing stuff hits the moon now and then, but one would expect the water to evaporate on exposure to the sun. The moon's known water (iirc) is at the poles, where the sunlight exposure is minimal, and I think Mars's water is the same way. 70.36.142.114 (talk) 14:05, 2 May 2014 (UTC)

Does evaporation defy gravity? Water cannot escape the Earth's atmosphere that way, so why should it escape the moon?--Shantavira|^{feed me} 14:30, 2 May 2014 (UTC)

For the same reason there's so little helium (second most abundant element in the solar system!) in Earth's atmosphere. Or, for that matter, why there's so little of anything in the Moon's atmosphere. TenOfAllTrades(talk) 14:40, 2 May 2014 (UTC)

See atmospheric escape. The Earth loses water all the time - or the hydrogen part of it anyway. (We should be ok for drinks until the Sun goes nova; there is water inside the Earth, and geological processes bring it up at roughly the same rate it is lost to space.)

Incidentally, we have an article on origin of water on Earth - it's not as clear cut as SimEarth taught us. 88.112.50.121 (talk) 15:11, 2 May 2014 (UTC)

Excellent read. Who would've thought that the molecules are literally wikt:hightailing it? MIND = BLOWN. - ¡Ouch! (^{hurt me} / _{more pain}) 08:51, 6 May 2014 (UTC)

Water can also hide below the surface, where permafrost may keep it frozen there for millions of years. But one question is if life can start when water only exists frozen below the surface. Another question is if people can extract that water efficiently for a colony there. We certainly need to become far more efficient at recycling water, too. No more flushing it down the toilet or draining it from the tub and forgetting about it. StuRat (talk) 15:34, 2 May 2014 (UTC)

Plant Intelligent/ brain theory

Charles Darwin first proposed that plants root system was a "brain-like" organ and a few studies have been done on plant intelligence. The question is 1. is the science sound enough to be put onto Wikipedia, and 2. should it get its own page or be a section on the plant page. Manofgun (talk) 14:17, 2 May 2014 (UTC) forgot to log in

See articles Plant intelligence and Hormonal sentience. 84.209.89.214 (talk) 15:26, 2 May 2014 (UTC)

I don't think any scientists argue that plants are intelligent, just that they mimic intelligence. For example, the roots will move towards a source of water or nutrients, but that doesn't require intelligence, unlike when people move their village from a dried up well to a good one. In the case of the plant, it could be as simple as those parts of the roots which get all the water and nutrients they need subsequently growing, while those roots which lack those ingredients withering. StuRat (talk) 15:25, 2 May 2014 (UTC)

( Yeah, well you obviously didn't spend to much time looking things up here, did you? Suffice it to say this is a huge topic in modern botany. Please don't be the second responder when you don't know much about the topic, and have no references to cite ) SemanticMantis (talk) 18:03, 2 May 2014 (UTC)

(Obviously, don't criticize a post unless you can prove where that post is in error. StuRat (talk) 16:13, 4 May 2014 (UTC) )

Oh thanks, when I googled it, the plant intelligence thing didn't come up. — Preceding unsigned comment added by Manofgun (talk • contribs) 15:44, 2 May 2014 (UTC)

Read this, and everybody have a toke . :) The mechanism must be ... something wonderful. Wnt (talk) 16:09, 2 May 2014 (UTC)

A scientologist (that's close isn't it?) thought so. The claim made at the time was that the tomato reacted electrically in anticipation of the nail. 84.209.89.214 (talk) 18:02, 2 May 2014 (UTC)

Sure, plants have "intelligence", insofar as they react to environment, make "choices", communicate with each other, etc. They can also cooperate or fight with other plants (allelopathy), forage for food, and exhibit tons of behaviors that we would readily see as signs of intelligence in other organisms. Just remember that this is a fairly metaphorical perspective. I don't think that plants have thoughts, but I don't think insects to either. And insect intelligence is well accepted. In addition to 84's good links above, See plant perception_(physiology), Plant_disease_resistance#Signaling_mechanisms, Phytosemiotics, and links therein. There's even a whole professional society for plant neurobiology [2]. Here's a nice article titled "Simple models of plant learning and memory", that talks about " intelligent responses to complex environmental signals" [3]. So, to answer your questions 1) Absolutely, as long as you can include references to WP:RS. 2) plant intelligence is the main article, but links between all these topics would work well, e.g. in the "see also" section of each article. SemanticMantis (talk) 18:03, 2 May 2014 (UTC)

While Mantis is clearly biased by his fealty to his plant overlords, the distinction he makes is an important one; certainly plants are not capable of cognition, as this process arises from discrete and highly specific biophysical processes known only to originate in certain tissues that plants lack, with no other alternative mechanisms for the phenomena ever suggested in serious modern scientific research; although, of course, it is postulated that the same or similar processes could be replicated in other materials aside from those they are known to occur in, they do not occur in any known plant matter. However, "intelligence" is a broad concept that, depending on context, can include most any of a complex organism's environmental responses. Historically, the term has not always been as applied to plants so readily as animals, owing in part to the speed of external (that is, typically mechanical) responses to such stimuli, but plants have a wide array of mechanisms for sensing their environment and adjusting their growth, movement, and other functions appropriately. Snow talk 21:04, 2 May 2014 (UTC)

Also worth noting that our articles in these areas are a bit of a mess. E.g. Cognition is defined in a way that make it unique to humans (via language), despite our article at animal cognition (and animal language for that matter). Maybe less contentious than "cognition" or "intelligence" is "information processing", and plants clearly do that (though that article is also a mess, btw). Anyway, I think you're right about historical biases, us naked apes like to think we're quite special. And of course it is only recently that we have the tools and conceptual understanding to demonstrate how plants communicate, make decisions, etc. SemanticMantis (talk) 21:32, 2 May 2014 (UTC)

You're quite right that our articles on the pheneomena of thought (or at least those which focus on the empirical etiology as opposed to pure philosophy) are all over the place in some respects (there's always more room at WP:WikiProject Cognitive Science if you would like to collaborate!), but I'm of two minds on whether or not that narrowness with which we treat cognition in some of the afore-mentioned articles is inappropriate; on the one hand, I'm a big proponent of animal precursors to "uniquely" human mental traits - on the other, the division you reference which utilizes dependencies on language, visual processing, and a handful of other mental constituents of cognition is fairly well-reflective of our sources and the current treatment of such issues within scientific literature broadly. While certainly it's foolish to insist non-human animals are incapable of thought, including such capabilities as causative association and complex planning, other abilities in the human mental repertoire, such as abstraction and other aspects of reasoning, are (I think reasonably) felt to be largely the purview of humans (or at least humans and our near relatives) linked to specific neurophysiological and proto-cognitive traits. This emphasis is partly due to the influence of evolutionary psychology, which lately has begun to have a huge impact on the way the cognition is perceived (and rightly so, in my opinion), although its worth noting that leading names in this field are themselves very cognizant of the chicken-and-egg complexities of linking cognition with language and other forms of mental symbolism. And of course EP is quite preoccupied with trying to determine which of the mental and physiological precursors of our ancestors led to the development of our unique psychological qualities. Anyway, returning to plants, as you say, information processing presents a useful distinction; ecophysiology is also useful in this regard, though it also preserves the dichotomy between Plantae and Animalia in regard to stimulus response. Snow talk 22:07, 2 May 2014 (UTC)

Maintain Hot Water

When I travel I have been lowering the temperature on my water heater. Is this necessary?

Does it take more energy to maintain a higher temperature than a lower one?

I know it takes more energy to achieve higher temperatures but, once achieved, does it also take more to keep them there?

Thank you — Preceding unsigned comment added by ChrisIsFromCanada (talk • contribs) 14:38, 2 May 2014 (UTC)

To maintain the temperature of something, you have to put in as much heat energy as it is losing. How much heat energy something loses is proportional to the difference in temperature between that thing, and the things around it. Hotter water loses more heat energy to its surroundings than cooler water, because there is a bigger difference between the temperature of the hot water and the temperature of the surroundings.

So, if your water heater is actually keeping a volume of hot water perpetually hot, then it will take more energy to keep it at a higher temperature. However, is this actually what it does? When you travel, does your heater at home really keep a tank of water hot for the whole time you're away? If so, do you really want to use that water when you get back? 86.146.28.229 (talk) 15:12, 2 May 2014 (UTC)

Sure, storage water heaters are the usual kind in Canada. And you're not going to drink the hot water, so any slight contamination due to leaving it standing for a few weeks is really no big deal. --50.100.193.30 (talk) 02:51, 3 May 2014 (UTC)

It makes a huge difference if it's winter or summer, since the heat which is lost all goes into the basement or utility room where the water heater is located, and eventually migrates to the rest of the house. In the winter, this isn't bad at all, and may even save you money, if your water heater is natural gas and your home is heated by electricity. In summer, on the other hand, not only do you lose the energy at the water heater, but your air conditioner will need to work more to keep the house temperature down. Of course, if you turn the A/C off when gone (which makes sense unless you have pets that would suffer), then that part doesn't apply. However, we're probably only talking pennies a day, in any case, so you decide if it's worth the trouble. StuRat (talk) 15:22, 2 May 2014 (UTC)

(ec)In real systems with imperfect insulation (i.e. all of them), yes, energy loss grows with the temperature difference between the warmer and the colder body. In systems where energy loss is dominated by heat conduction, and if I remember my undergrad physics correctly, energy loss is proportional to the temperature difference. So from an energy usage point of view, it's best to turn the heating off completely if you are away for a while. At least in Germany, however, the recommendation is to keep any warm water reservoir at at least 60°C, to eliminate the risk of Legionella. So either turn the heat off completely (to allow cooling below 25°C), or keep your heater at at least 60°C. --Stephan Schulz (talk) 15:27, 2 May 2014 (UTC)

However, in winter, there's also the risk of pipes freezing and bursting. To avoid this, keeping the water heater on high and letting the faucets drip may work. Although this is wasteful of both water and energy, it's less expensive than a water leak in the walls. StuRat (talk) 15:39, 2 May 2014 (UTC)

If freezing pipes during an absence are a concern, it's best to shut off the main water valve and drain the pipes by leaving the faucets open (and draining the water heater, which will have its own drain valve). On this page, for example, see the "When your home must be abandoned" section. But they're talking about situations where a power or other utility outage may shut down your heating system. In a properly heated house with the pipes properly insulated, they shouldn't freeze. But, of course, you never know what emergency may arise during your absence. --50.100.193.30 (talk) 02:51, 3 May 2014 (UTC)

Draining all the water out of all your pipes is a major operation, possibly involving disconnecting pipes, so not something you will want to do when just going away for vacation. StuRat (talk) 23:27, 3 May 2014 (UTC)

It's usually enough to just turn the water off at the mains and leave a few of your faucets open, particularly the lowest one, if you have one in the garden or something. You don't need to evacuate ALL the water from the plumbing, just leave enough room so that expansion of the remaining water doesn't burst the pipes. Vespine (talk) 23:17, 4 May 2014 (UTC)

Rhizobium spp. for pea/beans vs. clovers/alfalfa ?

My local garden centre sell Pea & Bean bacteria, without specifying which species of bacteria it is, only that it is for Phaseolus vulgaris, Phaseolus coccineus, Pisum sativum, and Vicia faba. Is the species of rhizobium for these peas and beans also suitable for clovers (specifically red/crimson and white) and alfalfa/lucerne? CS Miller (talk) 15:36, 2 May 2014 (UTC)

I'm sure that that product can't hurt clovers or alfalfa, and would likely help them just fine. My guess based on similar products is that there is a mixture of spore in that product, not just one type. There are several types of rhizobia, and some have a high degree of host specificity. This page lists some species pairings [4]. It seems to me that at least some microbes can nodulate all the species you list, but I don't have the time to go through it carefully. It would make sense for a commercial product to feature a mix of different generalists... These papers say that some plants and microbes have high specificity, and talk a bit about effectiveness [5]. [6]. SemanticMantis (talk) 18:22, 2 May 2014 (UTC)

Unless you're a commercial farmer who frequently spays with glyphosates and things, then I don't see the benefit of using any inoculation booster. There should be a sufficiently broad spectrum of these little bugs in the soil for the host to pick and choose from. For the commercial farmer there is a need for boosting because glyphosates inhibit the same metabolic pathway that most plants/weeds have (thus killing them) and so makes the soil very deficient in nitrogen fixing bacteria. --Aspro (talk) 22:14, 2 May 2014 (UTC)

Yeast vs bacterial culture

Is yeast culture much different from bacterial culture? Are yeast cells more fragile? There's an assay I'd like to do in yeast but I don't know whether it's worth the extra effort, if there is any. It looks similar but I say this with no experience beyond E. coli DH5-alpha. — Preceding unsigned comment added by 129.215.47.59 (talk) 18:03, 2 May 2014 (UTC)

Wikipedia has articles about Yeast and bacteria that you can read on your own. While both are single-celled organisms, they are not closely related at all. Yeast are eukaryotes and bacteria are prokaryotes; as evolutionarily speaking that was one of the earliest splits in the living world, the Most recent common ancestor of the two is VERY far in the past. You are literally a closer relative to any yeast than the yeast is to any bacteria. --Jayron32 18:08, 2 May 2014 (UTC)

I think a misunderstanding has occurred. My question does not pertain to how different bacteria and yeast are. I want to know how different the techniques used to culture them (in a lab) are. 129.215.47.59 (talk) 20:17, 2 May 2014 (UTC)

Think Fermentation in food processing might be more appropriate.--Aspro (talk) 21:16, 2 May 2014 (UTC)

What? No! I'm talking about a laboratory experiment. I want to culture them in small volumes (<1 litre) and on petri dishes. 129.215.47.59 (talk) 21:54, 2 May 2014 (UTC)

I'm not sure how much you might already know, but here are two descriptions of methods for yeast cultures in the laboratory [7] [8]. Seem that the techniques are similar to those for bacteria, but different. Beyond that, talk to your lab adviser or mentor. SemanticMantis (talk) 22:31, 2 May 2014 (UTC)

Fine. What strain of yeast or bacteria? They grow best, if conditions closely match their particular niche. Just as agar-agar in your Petri dish may require the addition of some beef stock or for aerobics a pinch of ascorbic acid etc. There is no universal method that suits all. Then there is the temperature to think about, some are thermophilics (like those you find in a steaming heep of horse dung), others (like those that bottom ferment larger) like cooler temperatures. Thats why labs have incubation ovens with an adjustable thermostat. --Aspro (talk) 22:34, 2 May 2014 (UTC)

Thinks to myself : “what lab experiment involving yeast is worth the effort”? Answer: Producing a litre of Saccharomyces culture to inoculate a malted wort to produce 3,000 gallons of brew to be distilled into some fine single malt whiskey. That to my mind would be worth the effort. Hmm, does the original poster have any distilleries in the country were he lives?--Aspro (talk) 22:58, 2 May 2014 (UTC)

Like. --Jayron32 23:36, 2 May 2014 (UTC)

My lab works with both bacterial and yeast cultures. The yeast cultures do not seem to take any more effort to grow than the bacterial cultures, except that they require different nutrition and different temperatures. So aside from minor details, the culturing protocols seem markedly similar. Someguy1221 (talk) 06:39, 3 May 2014 (UTC)

However, you must make yourself comfortable with the fact that since you are likely raising yeast on yeast extract, you are encouraging cannibalism. Someguy1221 (talk) 06:51, 3 May 2014 (UTC)

Image focus distance of relaxed eye lens

Human eye - click for full article

Eyes can be "rested" by closing them or focussing on a distant plane. At what distance does the human eye lens [muscles] become fully relaxed? --Seans Potato Business 21:58, 2 May 2014 (UTC)

Infinity (approximately)--109.151.101.168 (talk) 23:19, 2 May 2014 (UTC)

Yes. An eye that needs no correction for myopia (near-sightedness), hyperopia (far-sightedness) or presbyopia (the loss of focusing range during aging) when relaxed is focussed on infinity. It focuses when needed on close objects by the ciliary muscles 3 surrounding the lens contracting. This narrows the diameter of the ciliary body 4, relaxes the fibers of the suspensory ligament, and allows the lens 10 to relax into a more convex shape which better focuses divergent light rays onto the retina. 84.209.89.214 (talk) 23:26, 2 May 2014 (UTC)

Detail: presbyopia doesn't affect the far point. --Tardis (talk) 23:32, 2 May 2014 (UTC)

Note however that the resting focus of accommodation or dark focus is not the same thing as total relaxation of the ciliary muscles. --catslash (talk) 01:31, 3 May 2014 (UTC)

Did been a mirrors in the dark? That’s why, a eyes always been relax in the dark!--Alex Sazonov (talk) 06:39, 3 May 2014 (UTC)

Cats eyes are different, see Tapetum lucidum. 192.249.63.59 (talk) 07:28, 3 May 2014 (UTC)

If been a mirrors in the dark a optical effects must been seen another! A cats always had been another optical sphere in their eyes than had been a man.--Alex Sazonov (talk) 07:44, 3 May 2014 (UTC)

Almost are not been a refraction of light in the dark.--Alex Sazonov (talk) 07:57, 3 May 2014 (UTC)

I been thinking that a cats always had been a monochrome vision and they cloud been see a colors in bright.--Alex Sazonov (talk) 08:23, 3 May 2014 (UTC)

The article Dichromat has references to support its assertion that while their Triassic ancestors were trichromatic, placental mammals such as cats have lost the ability to separate green and red, and have become dichromatic. Dichromatic vision may improve a cat's ability to distinguish colours in dim light, though how is unclear. 84.209.89.214 (talk) 11:43, 3 May 2014 (UTC)

Thanks much!--Alex Sazonov (talk) 11:56, 3 May 2014 (UTC)

May been a electromagnetic induction in the light and in the dark always been different, thats why a optical effects in the light and in the dark always are been different?--Alex Sazonov (talk) 09:37, 3 May 2014 (UTC)

I don’t know but may been done a vision seen focus of a electromagnetic induction to been see it?--Alex Sazonov (talk) 11:37, 3 May 2014 (UTC)

Silicagel (orange to clear indicating) high temperature

I accidentially regenerated orange indicating silicagel in the hot air oven at 200°C, but later read that one should only dry it at 130°C at most. It produced a kind of weird smell, but looks like it is still working. Is it dangerous? Does that release any toxic components in the air? Or release any toxic componenets in the oven(I use the same oven for food)?

best thanks --helohe (talk) 23:39, 2 May 2014 (UTC)

You shouldn't rely on Refdesk answers for advice regarding your safety. In any case, it would be very hard to give such advice without a specific product and manufacturer indicated. Which brings us to the main point that it would make more sense to ask them. Wnt (talk) 23:47, 2 May 2014 (UTC)