Wikipedia:Reference desk/Archives/Science/2013 June 27

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June 27

Tsunami physics

The tsunami article alleges that a tsunami's wavelength is on the order of hundreds of kilometers long. But if a tsunami is caused by an earthquake, an event which lasts no more than a few minutes, then the tsunami's period cannot exceed a few minutes either. How then does a tsunami have such a long wavelength?

Also, I remember learning that a tsunami's long wavelength was somehow responsible for its large destructive powers. I don't remember why (something to do with energy), could someone help fill in the gap?

Finally, how does a tsunami not die out after travelling such large distances? 74.15.137.221 (talk) 01:56, 27 June 2013 (UTC)

My understanding is that a tsunami does not have a single wavelength, but rather a range of wavelengths, as it is originally produced by a disturbance that is rather localized in space and time. Because of the dispersion relation of the ocean waves, the waves of different wavelength have different velocity (that is, different phase velocity and different group velocity). As a result, the tsunami becomes progressively broader as it travels away from where the earthquake has happened. Also, if I remember correctly, deep-water waves of shorter wavelengths dissipate faster than the longer ones. --Dr Dima (talk) 02:43, 27 June 2013 (UTC)

Imagine that you whack a pendulum to make it start oscillating. The pendulum may have a period of several seconds, even though your hand was only in contact with the pendulum for a tiny fraction of a second. That's because the pendulum's period is determined by its physical characteristics--specifically its moment of inertia and center of mass--and not by your initial whack. Similarly, a tsunami's wavelength is determined by the physical characteristics of the ocean, not by the earthquake that caused it.

A tsunami's long wavelength means that when a leading trough first hits a shore, the shoreline recedes for a while before the peak hits (see Tsunami#Drawback). That doesn't make the tsunami more destructive, but it does mean that lots of people will be out collecting seashells in the newly exposed sand, unaware that they're about to drown. --50.125.28.190 (talk) 06:15, 27 June 2013 (UTC)

The pendulum analogy is nice but unfortunately incorrect. A pendulum - a simple harmonic oscillator, technically - possesses only a single mode of oscillation. Deep water, on the other hand, can have propagating surface waves of any frequency, with wavelength as a function of frequency being given by the deep-water wave dispersion relation, see Dispersion relation#Deep water waves and Dispersion_(water_waves). --Dr Dima (talk) 08:03, 27 June 2013 (UTC)

In an earthquake, the ground on one side of the fault line might suddenly drop or jump upwards by several feet - spread over an area measured in square miles. The mass of water that this displaces is spectacular - a 1 meter sea level change over one square kilometer is a million metric tons of water set in motion. In terms of waves - you get surface waves with wavelengths from a few centimeters to kilometers in length - propagating outwards as speeds that are proportional to the square root of their wavelength - so the longest waves arrive first as huge volumes of water moving at crazy speeds. But in deep water, these waves are extremely shallow - a tsunami wave can go past a boat (in deep water) without anyone even noticing - the boat might be lifted a few feet over the course of a minute and then lowered just as gently. Nobody would notice the tsunami going past them! As the water gets shallower, the math of their propagation speed and amplitude changes and refraction makes the wave turn to be roughly parallel with the shoreline and all of that long, slow vertical motion builds up in height from tens of centimeters to tens of meters.

Losses due to viscosity of the water and air resistance obviously do gradually sap energy from the waves - but there isn't much energy loss and a million tons of water packs a heck of a punch. These waves can circumnavigate the earth and still be measurable.

SteveBaker (talk) 13:37, 27 June 2013 (UTC)

Thank you. 74.15.137.221 (talk) 23:40, 28 June 2013 (UTC)

Plausibility of leaving message for police with bare finger?

In season 2 episode 4 "By the Book" of the crime procedural television series White Collar, a kidnapping victim, as she is being taken from her home, uses her bare finger (it is not dipped in ink or any other marking or sticky substance) to invisibly rub/spell out a word on the surface of her non-dusty (so she was not spelling out a message in dust) dresser without her kidnappers knowing. Later, when the FBI dust the crime scene for fingerprints, their dusting reveals the word she left, which the FBI uses as a vital clue that enables them to track down her kidnappers and her location and rescue her. Is this actually plausible, that the bare finger secretes enough liquids that, just by rubbing your bare finger on a surface, you can leave messages that the police will then be able to find? —SeekingAnswers (reply) 04:26, 27 June 2013 (UTC)

I haven't tried the experiment because I don't have any aluminium powder, but it sounds perfectly plausible. The cleaner the original surface, the more likely the oils from the skin will leave an invisible trace detectable by fine-powder dusting. (Advice to kidnappers: polish all surfaces before you leave!) Dbfirs 06:19, 27 June 2013 (UTC)

You can try it yourself without powders by doing it on a window or mirror, the writing is clearly visible - unless you've just washed your hands - I tried and directly after washing my finger left only a few faint marks. (Yes it's OR but easily replicatable.) Roger (Dodger67) (talk) 06:47, 27 June 2013 (UTC)

Also, what constitutes a "clean" surface? If it's a piece of polished wooden furniture, then there are who-knows-what waxes and oils on the surface that could be disturbed by dragging on them with a clean finger. But it's pretty obvious that if you can detect a fingerprint, you can detect a finger-smear. It seems entirely plausible. SteveBaker (talk) 13:15, 27 June 2013 (UTC)

Remarkable claim about handaxes

I was doing research on the handaxe and found these remarkable claims from this page:

"Handaxes were known to the ancient Greeks, who believed them to be the thunderbolts thrown down by Zeus, the Tree-splitter. They were held to be sacred and were put on display in the temples, such as the Temple of Apollo at Delphi, which had two of them."

I'm highly skeptical because I haven't seen these claims in any other source. Can anyone substantiate or refute them? --50.125.28.190 (talk) 05:58, 27 June 2013 (UTC)

See Labrys. --Dr Dima (talk) 06:02, 27 June 2013 (UTC)

Interesting article, but the Labrys is a bronze tool used by a Bronze Age civilization. The handaxe is associated with the Acheulean industry, 1.6 million to 0.2 million years ago, and was mostly replaced by better tools by 40,000 years ago. It would be remarkable if the ancient Greeks preserved some memory of this distant past. --50.125.28.190 (talk) 06:32, 27 June 2013 (UTC)

Surely the "Ancient Greeks" were just as capable as we are of finding hand axes and then concocting an explanation for them. Roger (Dodger67) (talk) 06:54, 27 June 2013 (UTC)

I highly doubt that. They had no army of trained archeologists who spend their lives finding prehistoric artifacts, and have decades of experience on where to look. Consider that the first Acheulean site was only found at St. Acheuls in 1847 (hence the name). I also don't think the handaxe looks remarkable or distinctive enough to have required a superstitious explanation. --50.125.28.190 (talk) 07:15, 27 June 2013 (UTC)

1847 was the first time they were intentionally and systematically studied but merely finding such objects is way easier and more common than that. In a ten minute random walk in certain parts of my father's farm one could easily find several stone tools just lying on the ground - finding them does require scientific knowlege about them. Ground up dinosoar fossils have been part of traditional Chinese medicine for centuries - long before anyone knew what they really were. Roger (Dodger67) (talk) 07:51, 27 June 2013 (UTC)

In this PhD thesis [1], on page 16, there's a short discussion and references. Please let us know if that's what you were looking for. --Dr Dima (talk) 07:35, 27 June 2013 (UTC)

Good find! From the thesis, I see the claim: "From the Temple of Apollo over two millennia ago, to the more modern era of bible-centric Creationist ‘science’ the presence of handaxes was conventionally explained as the physical manifestation of thunderbolts. In Ancient Greece, these were attributed to the gods (Montelius, 1910), and later on to nature, fitting into the notion that the world had existed since its Creation by God, in 4004 BC."

Montelius 1910 is "The Sun-God's Axe and the Thor's Hammer", available here on Wikisource. It seems that this article talks about the double-axe (shaped like the Labrys). None of the photos look anything like a handaxe, and although I haven't read the whole thing, I don't see any description that clearly matches the handaxe. Still, it was an interesting read. --50.47.81.232 (talk) 09:43, 29 June 2013 (UTC)

• The association does indeed exist. Even the words acme, heaven, Himmel and hammer, as well as the Slavic kamen, "stone" have the same root; see *ak in Calvert Watkins' dictionary. I don't recall the source, but stone battle axes were considered to have religious importance in pre-historic northern European cultures. μηδείς (talk) 19:29, 27 June 2013 (UTC)

See our article on Thor's hammer. μηδείς (talk) 20:00, 27 June 2013 (UTC)

TREES & SOIL WATER

Which plant takes more water than all other plants? — Preceding unsigned comment added by 112.79.37.226 (talk) 06:13, 27 June 2013 (UTC)

An aspen grove - a clonal colony - may well be a single plant (a single organism). If that's your definition of "plant", this may be the answer. If not, please let us know what you mean. --Dr Dima (talk) 07:46, 27 June 2013 (UTC)

Looking at both these questions together, you might find that the same species can both take up large amounts of water from the soil during rains, and take up little or no water during droughts. Cacti and succulents are two examples. This is similar to how animals in places with inconsistent water availability, like camels, can take up lots when available, and little or none during droughts. Other plants in places with a more regular water supply may lack the ability to store water in this volume, so must take up water from the ground more consistently. StuRat (talk) 06:37, 29 June 2013 (UTC)

SOIL WATER

Which plant takes less water than all other plants? — Preceding unsigned comment added by 112.79.37.226 (talk) 06:16, 27 June 2013 (UTC)

I'm not sure, but that would be some desert plant (maybe a cactus, or a creosote bush?) 24.23.196.85 (talk) 07:13, 27 June 2013 (UTC)

I LOVE SCREAMING! Plasmic Physics (talk) 10:32, 27 June 2013 (UTC)

It's hard to find a reference - but I'd put my money on some kind of lichen. Some species can live on a rock (not much scope for roots!) in a dry desert and take thousands of years to grow to an inch or two in diameter - when there is no water present at all, they can shut down their biochemistry and lie dormant for extended periods - using no water at all.

The problem with this question (and the previous one) is that plants can lie dormant for extended periods using no water at all. So should we consider dormant plant seeds? Those have been found in sealed stone jars, 2,000 years old - and have been planted and watered - then germinated and grown. If we take an average water consumption over the entire life of the plant - it's almost zero...but when it starts growing it may need quite a bit of water. We need a better definition of what the questioner actually needs to know.

Generally, knowing why the questioner needs this answer would help (eg: If you're a farmer in a dry part of the world, then ask us which crop needs the most to get a good yield - but if you're a NASA scientist planning to take plants on a trip to the moon to test them, or someone who doesn't like to water their back yard yet still have it look nice - then the answer is very different!

Probably, this is just general curiosity (which is a perfectly reasonable purpose for asking a question here on the science desk!) - in which case you're going to get a range of often conflicting answers - but you'll probably learn something interesting!

SteveBaker (talk) 13:05, 27 June 2013 (UTC)

Lichen aren't exactly plants, for what it's worth. They are fungus-alga symbionts (or in some cases, fungus-cyanobacteria symbionts). The alga or cyanobacteria provide the photosynthesis but the fungus provides the "body", to so speak. Their water needs differ from regular plants as a result. Just saying. Pfly (talk) 05:14, 28 June 2013 (UTC)

Since this question is about plants that don't take up much water from the soil, perhaps we should look at plants which capture water from water vapor in the air, rain, or suck it out of other plants and animals. There are also floating plants, like the water lily, and they presumably get their water directly from there. StuRat (talk) 06:49, 29 June 2013 (UTC)

Human Subspecies

LINK Can anyone inform me on the validity of this work? Thanks. --OptionalCommune (talk) 10:44, 27 June 2013 (UTC)

Perhaps others will answer, but I suggest that you take the time to summarize the points of interest, and ask a specific question. Simply providing a link to a blog demonstrates scant effort, and the volunteers who answer questions here should not be expected to show more. -- Scray (talk) 11:04, 27 June 2013 (UTC)

Sorry, the summary provided is as thus:

"The term race is a traditional synonym for subspecies, however it is frequently asserted that Homo sapiens is monotypic and that what are termed races are nothing more than biological illusions. In this manuscript a case is made for the hypothesis that H. sapiens is polytypic, and in this way is no different from other species exhibiting similar levels of genetic and morphological diversity. First it is demonstrated that the four major definitions of race/subspecies can be shown to be synonymous within the context of the framework of race as a correlation structure of traits. Next the issue of taxonomic classification is considered where it is demonstrated that H. sapiens possesses high levels morphological diversity, genetic heterozygosity and differentiation (FST) compared to many species that are acknowledged to be polytypic with respect to subspecies. Racial variation is then evaluated in light of the phylogenetic species concept, where it is suggested that the least inclusive monophyletic units exist below the level of species within H. sapiens indicating the existence of a number of potential human phylogenetic species; and the biological species concept, where it is determined that racial variation is too small to represent differentiation at the level of biological species. Finally the implications of this are discussed in the context of anthropology where an accurate picture of the sequence and timing of events during the evolution of human taxa are required for a complete picture of human evolution, and medicine, where a greater appreciation of the role played by human taxonomic differences in disease susceptibility and treatment responsiveness will save lives in the future."

--OptionalCommune (talk) 11:46, 27 June 2013 (UTC)

I'm thinking troll... no, not you, gentle OP, I mean Woodley. To begin with, I can think of no two words that give a greater impression that an otherwise clever-sounding idea may be totally wack than "Medical Hypotheses". Also, his suggestion that there is a "Homo africanus" seems bizarre - if you believe there's one subspecies in Africa, you have to believe there are three or more. Last but not least, his claim that Victorians were smarter because they had a faster reaction time [2] which is based on a weak correlation. From our article it would appear chewing gum makes you smarter also. Plus, the idea there that weakened natural selection is making us all dumber has a creepy vibe along with this that makes me think that the ghost of Spencer is seriously begging for a dose of salt and burn. (To be fair, the sort of epigenetic Lysenkoism I'm more open-minded toward doubtless has its own creepy vibes...) All that said, though --- trolls have their purpose. It is hard to define subspecies, and for various cultural reasons it is difficult to do so, and the most interesting cases seem little researched and worthy of a bit more attention. It does seem like "Pygmy" groups like the Twa are interesting, in part due to some degree of reproductive isolation. History tells us again and again that new species of humans burst forth onto the world out of Africa, and I am partial to the notion that they will be next: futurists often speak of descendants of man with giant heads, but small bodies are an evolutionarily easier route to greater efficiency for space colonization. Because Pygmies can presumably write just as much code and run just as many robots as anyone else, they should enjoy a small but exponential advantage that will lead to their predominance in the universe. Wnt (talk) 11:51, 27 June 2013 (UTC)

This certainly appears to be junk. The problem is that when you talk about genetically distinct sub-groups (which is what that fancy words "polytypic" (having more than one sub-group) and "phylogenetic" (grouping determined by gene sequencing) means), you have to ask what set of genes you're talking about. The author clearly wants to get back to old-school racism by picking the set of genes that determine skin color. However, that's only one way to slice the pie. Why pick that set of genes rather than the ones that determine (say) lactose intolerance, color blindness, musical ability or finger length?

The key to thinking about this is a term called "the fixation index" - which basically asks: How much of the genetic variation present in the entire species is found between your proposed sub-groups? So if (for example) you found a group of organisms who were genetically much more similar to each other than they are to other individuals in their species - then you might identify them as a different sub-species - but if you find that there is almost as much variation within that sub-group than in the species as a whole, then that division makes no logical sense.

When you do that with humans you find that no matter how you group people (eg by skin color, lactose-tolerance, color blindness or whatever) 85% of the variation measured across all humans on earth is found within individuals of that group. That is to say that two randomly selected Inuit people exhibit 85% as many genetic differences as (say) an Inuit and an Australian Aborigine...and two randomly selected color-blind people also exhibit about 85% as many genetic differences as color-blind and not-color-blind people selected at random. So the basis of splitting them into different sub-species is very narrow indeed. It's very likely that an Inuit with lactose intolerance is more genetically similar to an Aborigine with lactose intolerance than he is to his next door neighbor.

Put another way: Skin color tells us that changes in just three or four genes is enough to produce the difference between dark and light skin. Lactose intolerance says that mutations in two genes produces that effect. Color blindness involves more than fifty different genes. So genetically, skin color (as way to determine a sub-group of humans) falls somewhere between lactose intolerance and color blindness as a determining factor. If you try to take a wider view and group more genes together to define a particular race, then you get more and more variations between individuals of that race and drawing a genetic map becomes harder and harder.

So if you're going to define genetically dissimilar sub-species, then perhaps it's better to split our world into two races - the lactose intolerant and the rest. The trouble with that is that there are a hell of a lot of ways to slice the pie - and there is no obvious way to pick which one...unless of course your some kind of evil racist who thinks skin color is the determining factor just because it's where some inner historical hatred lies...and that's not science.

You can define race by ethnicity or by historical migration patterns - but you just can't do it with genetics.

SteveBaker (talk) 12:50, 27 June 2013 (UTC)

There's a little more to it than that - our article on Fixation index cites rates up to .19 for Yorubans (didn't check but presumably from here, and our rivals at Metapedia (a site to be seen to be believed - check out their collections on "sexual Bolshevism"...) do point usefully at [3] illustrating that the threshold for subspecies is a bit low in some hands. Everybody loves a chance to name something... :) But the difference to Homo neanderthalensis, nominally a whole different species, isn't that great, and there are differing degrees of admixture of this species in contemporary populations for that matter. I should note I didn't find Fst analysis for the Twa or other Pygmy groups (which are apparently quite divergent from one another) and remain curious. Bottom line: I don't think we can rule out finding a few nominal human subspecies somewhere, at least not under all possible semantics and given the fairly limited amount of sampling we've done in Africa. Wnt (talk) 13:27, 27 June 2013 (UTC)

100 ml rule

Is there any scientific reason behind the 100 ml carry on limit for liquids on planes (other than selling more water in airport shops)? Main question: Why liquids? Why 100 ml? bamse (talk) 14:14, 27 June 2013 (UTC)

That restriction was instituted in the wake of the 2006 transatlantic aircraft plot, which involved liquid explosives. — Lomn 14:19, 27 June 2013 (UTC)

Sure: it's the science of operations research, the scientifically-founded engineering discipline of making an operation work smoothly. Blanket bans on all suspicious items makes the security check faster, and therefore more efficient. In the U.S., if you're travelling on a commercial airline and you're willing to spend lots of time before and during travel, you can file lots of paper work to get permission for all sorts of "special items", as long as you comply with federal regulations and your airline policy. But at the checkpoint, the objective is to screen all passengers as efficiently as possible; the rules are set up to keep dangerous items out of the secure area without requiring a lengthy and invasive search of every single item.

For all the bad press the TSA receives, it's worth reminding the world at large: this week, like each and every week, millions of travelers are mildly inconvenienced about their bottled water and a few dozen loaded handguns are caught at the checkpoint. This happens every week. I would propose, from the standpoint of applying the scientific method, that the current method of screening - including blanket bans on apparently-benign items like bottled water - is a more effective method for keeping the handguns off the aircraft. Unfortunately, like most social sciences, it is impractical to conduct a control experiment. Nimur (talk) 17:03, 27 June 2013 (UTC)

Actually, Nimur, the more relevant link is to Security theater. The airline industry, and the U.S. Government, can do very little to stop a properly determined, trained, and equipped person from causing massive havoc. If we knew this, we wouldn't fly. So, they institute a series of (entirely ineffectual from a security standpoint) measures designed to give the impression that they are doing something, so we're more likely to spend money buying plane tickets. All arbitrary and restrictive security rules that seem outwardly benign (such as restrictions against bottles of water and requiring passengers to take off their shoes in security lines) fall into this security theater categorization. There are some security measures (such as restricting the use of actual explosives and firearms on planes) which are probably actually effective, but the types of measures the OP is noting are not among them. --Jayron32 17:12, 27 June 2013 (UTC)

Security theater, yes; but I prefer to think of it as a different stage-trick altogether. While everybody is focusing on bottled water, to which the TSA draws your attention through theatrics and loud public debate about civil-liberties; behind the scenes the TSA and its law enforcement partners are bagging fifty gun-toting airline passengers a week, and all without frightening the air-travelling public. Perhaps I ascribe too much competence to the Government's ability to keep quiet about its actual policing activity; ironically, my theory is frighteningly more Orwellian than yours. Nimur (talk) 17:32, 27 June 2013 (UTC)

I'm not sure it's that ironic, and I'm also not sure that you're theory is one iota different than mine. --Jayron32 17:39, 27 June 2013 (UTC)

We're getting off topic, but I would like to point out that guns were caught pre-TSA as well. Metal detectors and x-ray systems were already in place as standard security. — Preceding unsigned comment added by 209.131.76.183 (talk) 17:51, 27 June 2013 (UTC)

Hm, so you are saying the size of 100 ml is completely arbitrary!? It is not related to any maximal-achievable-explosion/damage with this amount of of explosive? bamse (talk) 18:46, 27 June 2013 (UTC)

I don't think it's completely arbitrary. However, I also don't think there's been enough information released by the TSA, etc, to conclude that it's completely objective, either. Various critics have noted, for example, that even if the personal limits on liquids (because it's not "100 ml"; it's however many 100 ml bottles you can fit in a 1-quart bag) is small enough to prevent an incident, it doesn't protect against 5 people each carrying the personal limit and then pooling their stuff after the security checkpoint. As with all countermeasures, then, it is someone's attempt to create a reasonable standard. How successful that attempt has been is, as you can see above, a matter of some debate. — Lomn 19:06, 27 June 2013 (UTC)

• This is pretty obvious. Laws have to be written objectively, and if a limit is given a reasonable round number that fits the concerns will be chosen. IT is like picking 18 or 21 for the drinking age. If they are going to pick some number then they have to chose some arbitrary number. The point is that we don't give a drinking age of 5 or 55, but somewhere near physical adulthood, and we don't put a limit of 1ml or 1 cubic meter on carry-on liquids because were are looking at a threshold size for effective but hideable explosives. Of course a pint would have been a much more reasonable measure, but that's a separate question. μηδείς (talk) 22:27, 27 June 2013 (UTC)

This rule was actually devised and adopted by the International Civil Aviation Organisation. You can see the state letter here. 202.155.85.18 (talk) 04:07, 28 June 2013 (UTC)

Why don't we have an Atomexpo page?

http://www.presstv.ir/detail/2013/06/18/309646/iran-invited-to-attend-atomexpo-2013/

Is it the lack of coverage in the western press? (I predict that's not going to be a problem in say 48 hours.) Hcobb (talk) 15:28, 27 June 2013 (UTC)

Because Wikipedia is an encyclopedia, not an indiscriminate collection of information; and/or because nobody has made the article yet (which bears somewhat on the conference's notability). Items need to be encyclopedic to merit inclusion. For comparative examples of energy technology conferences, we have an article on Offshore Technology Conference, but as of this writing, we do not have North American Petroleum Expo, even though NAPE is probably almost as big an event as OTC. (Well, by number of attendees it's much smaller, raising another issue - how does one measure notability and importance of an Expo?) Would an encyclopedia article on such a conference add any value to our encyclopedia? If so, please take the initiative and start the article. Here is the official English webpage for the 2013 Atom Expo, sponsored by Rosatom. Nimur (talk) 16:30, 27 June 2013 (UTC)

The way we should measure notability is by having multiple sources about something, and it shouldn't be a high bar - most Wikipedia articles haven't been written yet. That said, there's a lot of politicking and out-and-out PR work about it nowadays. If you look at Portal:Featured_content you'll see that much of Wikipedia's "best" work amounts to ads about very obscure people and events who have something to sell today. We have featured articles about individual wrestling pay-per-view matches, and vast numbers of people who will staunchly defend that a few industry magazines amount to comprehensive secondary-source coverage. Meanwhile anything someone finds offensive (often for personal reasons) or which potentially competes with news wire services is proposed for deletion. There's nothing rational about it - there is no policy, not really - it's naked power politics. Wnt (talk) 23:55, 28 June 2013 (UTC)

Quantum chaos

Here's my question: Does the lack of chaos in a quantum system explain evolution within biology perhaps? I scoured the internet and didn't find much information about it. I found a slight reference to it on Scholarpedia.org (the article named Quantum chaos). You may put complex math equations but don't expect me to understand; math is the exact opposite of what I'm good at (I am a spirituo-creative.). Thanks. Lighthead ^þ 18:56, 27 June 2013 (UTC)

(We have our own quantum chaos article BTW). Evolution isn't much of a quantum-level thing. All it requires to operate is some means by which an organism can hand on it's genetic code to it's offspring - and for there to be occasional random errors in that information along the way. If quantum effects were large enough to significantly change that then we probably wouldn't have stars and planets, let alone living things! SteveBaker (talk) 19:14, 27 June 2013 (UTC)

Actually, I meant the whole origin of life. I'm sorry if I was unclear. Because from what I understand the fact that life even exists flies in the face of traditional chaos theory. Life seems to be heading towards low entropy (according to the theory of evolution as I understand it) as opposed to high entropy as chaos theory predicts. Sorry for the slow response; I completely forgot that I posted this. Lighthead ^þ 00:12, 29 June 2013 (UTC)

Also, that article is impossible to understand for the layman. I, surprisingly, found the article on scholarpedia much easier to understand. Lighthead ^þ 00:18, 29 June 2013 (UTC)

Chaos and entropy are not that strongly linked, so I think the premise of original question was not strong. The notion of life as conflicting with the second law of thermodynamics is oversimplified, because the second law addresses the entropy in an isolated system, so one would have to consider macromolecules, respiration - many components in a very complex dance. As is often the case, we have an article on that: Entropy and life. -- Scray (talk) 01:10, 29 June 2013 (UTC)

Thanks for the article. I will read it. Lighthead ^þ 03:36, 29 June 2013 (UTC)

I read most of the article. Pretty interesting. It really led me to make some interesting conclusions. I still have to think about how it relates to my original question, but at least for right now, it's an interesting aside. Thanks again. Lighthead ^þ 03:58, 29 June 2013 (UTC)

How scientist calculates how stars evolves

When sun expands to maximum size I thought scientist exactly knows how bright the sun will get when reaches RGB tip in 7.6 billion years of between 2000 and 3000 times current luminosity is this possible there are other answers than that. I have navigated through many websites I don't know if I paid attention to their luminosity variables although some websites don't mention how much will sun cools of by the time it reaches gigantic orbs. It is not going to be over 10,000 times the current luminosity, and also do we know exactly how much will the sun cools off?, is this possible there is wide range of answers, impossible to hit the correct pin? I remember Schroeder and Smith and Once and Future of Sun definitely use computer simulation to do the calculations, I just learned computer simulations isn't more accurate than natural calculations. Do scientist build a powerful telescopes to imitate foreign stars what life cycle they have gone through will the solar system? Will space telescopes how can they make predictions, or is it just once scientist build stronger telescopes, they always come up with better answers because they can track more details.--69.233.254.115 (talk) 20:30, 27 June 2013 (UTC)

A lot of this is done simply by looking at what kind of stars exist now in what quantities and figuring out how certain classes of star observed could evolve into other types. It's like taking a picture of a herd of antelope on one day in summer and figuring out that if half the antelope are yearlings, and the rest are aged adults, that most of the yearlings are going to have to die, or the population would be skewed. You don't actually have to watch the babies get eaten to figure out a reasonable population model for the whole herd. Astronomers come up with models to fit the populations of stars e see. We have resident astronomers, so hopefully someone can say something more detailed and intelligent. μηδείς (talk) 02:03, 28 June 2013 (UTC)

The article titled Stellar evolution is a good place to start researching this topic. --Jayron32 05:40, 28 June 2013 (UTC)

Evolution

Are today's chimpanzees, or other great apes, just humans in waiting? Will they eventually inherit human genes/DNA or will they evolve into a separate, distinct species? I'm just curious if evolution results in the extinction of one species; for example, if humans will evolve into something else and chimpanzees will evolve into humans, and if that would continue in a cycle? --Andrew 22:06, 27 June 2013 (UTC)

This is a pretty standard "intelligent design" or anti-evolutionist question. Organisms simply evolve according to immediate circumatsnaces, not some goal. Here are various responses. The Livescience one is recent and reliable. The underlying fallacy is the assumtion that humans are something that exists prior to and outside evolution and that the goal of evolution is to move toward humanity. That's based on an unscientific view of evolution and the idea that one's own personal existence is some part of a plan. See anthropocentrism, as wel as Mediocrity principle and Copernican principle. μηδείς (talk) 22:18, 27 June 2013 (UTC)

Let's look at the probable chain of events leading to human intelligence, and see which might apply to other primates:

1) First our ancestors lived in trees, and this arboreal environment led to the opposable thumb, which is useful for holding onto branches. All primates share this feature.

2) Our ancestors then moved to living on the plains, which meant that bipedal motion was of value for seeing above tall grasses. Most primates still live in the trees. There are some primates which live on the plains, like baboons, but so far they don't seem to have developed full time bipedal motion. I'm not quite sure why, though.

3) This combo of opposable thumbs and bipedal motion freed up our hands for tool use (probably just using rocks as weapons to start with). Some primates (and other animals) have used tools, but they always seem to be temporary tools which are discarded as soon as the task is completed. Perhaps the lack of free hands accounts for this, as there's no easy way to carry them.

4) Permanent tool users then can benefit from increased intelligence, in order to perfect each tool. The ability to pass down this knowledge also requires communication, which also requires increased intelligence.

So, it seems to me that the lack of bipedal motion is the stopping point for other primates. This might be partially due to humans being in control of this niche, so there really isn't room for many other primates to move into plains and develop bipedal motion. So, if humans were all gone, it's possible that other primates might well move into the niches occupied by humans, potentially leading to increased intelligence in the same way. Certainly it's not guaranteed that evolution would point that way, though.StuRat (talk) 06:26, 29 June 2013 (UTC)

Since we're talking about evolution...

My understanding of natural selection is that it's based on tiny natural mutations over many generations that occasionally favours individuals who then manage to pass on their advantageous genes. So... why isn't intelligence more widespread? Since insects have a zillion generations a year, for example, and any increased intelligence or awareness would presumably favour an individual, why are we not surrounded by super-intelligent houseflies? (NB, I am not pursuing an agenda here, I am just interested in the scientific answer which I'm sure someone will quickly furnish me with) FreeMorpheme (talk) 22:35, 27 June 2013 (UTC)

Intelligence requires computation, and computation is expensive. An insect with a three pound brain (like a human has) wouldn't do very well, regardless of how smart it was. Insects actually get quite an extraordinary amount of intelligence out of their tiny little brains. Looie496 (talk) 22:53, 27 June 2013 (UTC)

Yeah, brains are very expensive in terms of energy consumption. For example, although the human brain comprises only about 2% of a human's body weight, it consumes up to 20% of the energy used by a human. See Human brain#Metabolism. Smarter isn't necessarily an advantage if the larger brain can make you more likely to starve to death. Red Act (talk) 23:13, 27 June 2013 (UTC)

Whatever works survives. Insects do well with their tiny brains and short-life circles, that's enough to reproduce before they die. Evolution doesn't go in the direction of 'better' or more capable species, sometimes it even simplifies things. Some species have lost their eyes or legs. OsmanRF34 (talk) 23:00, 27 June 2013 (UTC)

• Intelligence is widespread (there are no macroscopic land animals without brains) and the trend is toward greater intelligence the more derived a clade is among mammals. For example, the most derived even-toed hoofed mammals are whales, and the most derived birds are the higher land birds, especially parrots and songbirds (think crows). μηδείς (talk) 01:52, 28 June 2013 (UTC)

You could think of it this way as well, what sort of human type intelligence do you think would benefit a housefly. Remember, it is still a housefly, it doesn't have coached reasoning skills, knowledge, any of that stuff, it basically has what a chimp has in a fly body. It can't see any better, it can't judge what it is naturally attracted to or repulsed by any better. What humans have which sets them apart is not only, and not even more significantly, confined to the brain. Dolphins neurology is more developed than humans, and the only thing they seem to benefit from that is bravery and compassion. They don't even have the most developed speech in the wild, even though they are very responsive to human training. Any tricky little things they do naturally can be quite encouraging, but not extraordinarily amazing compared to all other animals. A human with basic knowledge of toolmanship, is not only a clever creature, but is a deadly dangerous one. Humans are fast runners, great climbers (humans are slower climbers than goats but can climb things even goats cannot climb), and if you'd nothing else to do but swing around in trees for fifty years or climb rocks, you'd have an iron solid gymnastic strength, with heavily padded hands and feet and nails like wood. Today we think that our brains are what we had going for us in the natural world but in fact we are domesticated and domesticated creatures resemble creatures which are not very healthy, bald, pallid, skinny, and weak. The question is not, does it make sense that houseflies exist without human intelligence, it is, how do humans survive WITH their intelligence! If you want to know what creature is amazing, it's not one with big brains, it's the shark. The shark is the most amazing organic machine there is. But don't forget, you are not a lion or a shark. If a shark met a lion, it would say hello by sinking its teeth in, and if a lion met a shark... yep. ~ R.T.G 21:22, 28 June 2013 (UTC)

Chimps are orders of magnitude more intelligent than flies, including the ability to reason out the solution to problems (relatively simple problems compared to what humans can solve, of course). StuRat (talk) 06:00, 29 June 2013 (UTC)

It is interesting to consider the effects of rapid environmental change. Humans might well have originated in regions of Africa with huge yearly changes in conditions - vast areas of flooding that turn to wildfires and desert over the course of a year. Now humans seem like the ultimate invasive species, and that seems largely due to high intelligence. But as the global climate changes over and over, not merely from ice ages but from global warming, deforestation, and above all transshipment of species around the world, as species hybridize and achieve greater genetic diversity under these conditions... I wonder how many other species have been pushed roughly onto the road to intelligence, and how long it will take? Wnt (talk) 23:49, 28 June 2013 (UTC)

The remarkable thing about human intelligence is that we are born knowing almost nothing. For example, look at walking. While many other animals are born with the instinct to walk, and are up on their feet in minutes, it takes humans months or even years to learn to walk. This is because it's vastly more efficient to be born already having instincts to do such things than to have to learn them from scratch. The advantage of learning so much is that it allows us to be far more flexible, and survive in many more environments. For example, we aren't designed just to eat one type of food. We can adapt to many different kinds of food, even those which are poisonous until we cook them, etc. On the other hand, if you transported a polar bear to Polynesia, it wouldn't be likely to figure out how to eat coconuts. StuRat (talk) 06:08, 29 June 2013 (UTC)

Well, I didn't find video, but if a polar bear failed to manage to eat coconuts when available I would be very disappointed in it. Only experiment can resolve questions like that. :) Wnt (talk) 17:29, 29 June 2013 (UTC)

Some scientists would argue that the advantage of being born *prematurely* compared to the other apes, is that compassion and community become essential. If you don't pick a human baby up it will not survive for instance whereas a chimp baby will cling on for itself. ~ R.T.G 21:03, 29 June 2013 (UTC)

I would suggest though Stu, we might be born without ability rather than knowledge. A new born baby can cling hard enough to be lifted off the ground, though I wouldn't encourage you to try that, and apparently new born babies can hold their breath and even swim. There is certain mechanical aspects to everything perhaps. Humans do not just think we are smart, we think we are special smart, and there's a bit of a dumb feel to that. ~ R.T.G 21:06, 29 June 2013 (UTC)

Privately towing a car with the handbrake engaged

Can you tow, with a private car (140 HP), another car (more or less same weight) which has the handbrake engaged? OsmanRF34 (talk) 22:37, 27 June 2013 (UTC)

If you're asking whether it is possible to make the second car move, that would depend on the quality of the handbrake. as well as the weight and gearing of the two cars. This is a strangely bizarre question for you, Osman. Looie496 (talk) 22:49, 27 June 2013 (UTC)

I don't find it bizarre. Every now and then some guy (the same) parks in my parking space. That would be the fast and dirty solution. I don't mean to tow him away some miles, just some feet. OsmanRF34 (talk) 22:54, 27 June 2013 (UTC)

Well, from a technical point of view, you can almost certainly tow him if only the handbrake is engaged. But if a gear is engaged (or, for an automatic, if the car is in "P"), this will be much harder, and, even if it succeeds, may cause significant damage to the drive train. --Stephan Schulz (talk) 00:05, 28 June 2013 (UTC)

But, if a gear is engaged and you tow in the 'right' direction, would it still cause damage?

Another point, is it only possible to move it if the wheels spin? In a real-life scenario, can't you just drag a car, with the wheels blocked? OsmanRF34 (talk)

• Seriously, Osman, do you expect us to have an encyclopedic source that will tell us whether your dad can beat up the other guy's d....I mean, whether your peni....I mean whether your car can tow his car even if braked? μηδείς (talk) 01:57, 28 June 2013 (UTC)

Sure. It's a physics problem. Given the weight, the HP, the friction, is it possible? OsmanRF34 (talk) 08:17, 28 June 2013 (UTC)

Yes, it will almost certainly be "possible" (I've been tempted to do it myself!) but that doesn't mean that it's advisable, because the owner of the towed vehicle is likely to make a claim for damage (real or imagined). Dbfirs 08:13, 28 June 2013 (UTC)

I used to work in a vehicle auction house. Basically this consisted of 18 months spent reverse-parking cars and vans in varying states of repair. Because many of the vehicles had been standing around for 6 weeks or more, flat batteries and binding brakes were an almost daily part of the fun and games to be had. What follows are my personal reflections and recollections. I do not make any comment on the legality or advisability of moving a car that is not your own.

If the car to be towed is in neutral with the handbrake off, it should be easy to move, either with another vehicle or even a hefty push by hand. Note, however, that if the steering lock is engaged, you will have no say on the direction it goes in. You also won't be able to stop it easily once it begins rolling - you may need someone to tug on the underneath of the rear bumper (fender) to bring it to a halt. Whatever you do, don't be tempted to stand in front of the moving vehicle and stop it by pushing in the opposite direction.

If the handbrake is on (or if the brakes are off but binding), but the vehicle is in neutral, you should still be able to move it. A slightly larger and more powerful towing vehicle than you describe would be preferable (ideally a diesel engined manual with 200+ bhp) but it's still worth a try. Attach a tow rope to the towing eye of your vehicle and the vehicle to be towed. Make sure it is securely attached and that it's not attached to the bodywork - you WILL rip off a bumper otherwise. Gently roll forwards in your car until the rope is tight. Then engage first gear, bring the revs up to about 2000 and slowly lift the clutch. Again, remember that your brakes only stop your own vehicle - the towed car will keep moving once rolling. If you keep the speed low, it should come to a gentle rest against your rear bumper, but again a friend to slow it down would be a bonus.

If the car is in gear (or in park in an automatic) - do not attempt to tow it or push it. You won't go anywhere and could cause damage. In this situation we would usually 'bounce' the car out of the way. You need at least two people, and what you do is position yourselves on opposite sides of the rear of the vehicle, push sharply down on the bodywork above the rear wheels and release. Keep doing this a few times in rhythm and the car should start to bounce, with the rear wheels briefly leaving the ground. Once this starts, keep bouncing, but exert gentle pressure in the direction you want the car to go.

I'll note that none of these options are likely to be discreet. Someone is almost certain to spot you doing it, and the car's owner will definitely turn out to be 6'7" tall and built like a brick outhouse. You might want to keep your engine running for a speedy getaway. - Cucumber Mike (talk) 08:47, 28 June 2013 (UTC)

Have you mentioned the issue to the property manager? Or if there are phone numbers posted in the lot for a towing company that enforces the parking rules, you could call them directly. They'll tow the car off to their lot and charge the owner a decent fee to get the car back, which hopefully will convince them not to park there again. 209.131.76.183 (talk) 11:30, 28 June 2013 (UTC)

I'll also add that it is probably a bad idea for you to mess with the car yourself. You don't want to be liable for any damage you accidentally cause. The tow company has insurance for that, you don't. 209.131.76.183 (talk) 11:31, 28 June 2013 (UTC)

Definitely a bad idea to dink with someone else's car. ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:44, 28 June 2013 (UTC)

If you do that, for stopping a car in movement, put something below the wheels, a plank or something. Trying to push is a very bad idea, trying to pull not so bad, but ineffective, unless the floor is flat. 80.58.250.84 (talk) 17:40, 28 June 2013 (UTC)

• Think the OP has got too emotionally involved to think in basics. Look at this from the others point of view: They have parked there several time without complaint so (to s/he or its point of view) it must be OK with the PS owner. So, just place a note on his windshield to the effect... I have noticed you have parked here several times before, so I have made a note of your licence plate. Should you need to park around this area because you need to make an emergency call to one of my neighbours who's space is already taken up, then please phone me on my mobile xxxxxxxx and let me know. Thanks. Don't add further details about the inconvenience , frustration etc., that it is causing you – if the driver is reasonable that should be enough for him to get the hint. After all, the driver may turn out to be a really nice guy and useful to get to know. Think serendipity.--Aspro (talk) 18:18, 28 June 2013 (UTC)

If this were my problem, I'd be looking at using a set of wheel skates [4]...or better still...[5]. Maybe you could rent a set someplace? Anyway, the latter kind fit around the wheels then tighten up to lift the car slightly off the ground onto a bunch of little caster wheels. Then you can easily move the car around with just one person pushing it - no matter whether the car is in gear, in park or has the brakes locked on. So long as the ground is smooth - it should roll very easily. No towing required! SteveBaker (talk) 20:42, 28 June 2013 (UTC)

Anyone advising the OP to mess with someone else's car may be advising them to break the law and/or to invite very serious trouble. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:41, 28 June 2013 (UTC)

I should point out that a normal tow truck routinely used by business owners avoids the costly consequences of messing with a car on an amateur basis. The way I understand it, predatory towing remains a lucrative industry in many places, so I wonder if it's really so difficult to work out an arrangement with some company provided you have at least a nominal right to claim the space. I would assume that going along with the established racket has the added benefit of sticking the victim with a huge bill rather than leaving yourself in legal jeopardy. Wnt (talk) 23:44, 28 June 2013 (UTC)

Yes, as with the infamous Lincoln Park Pirates in Chicago. ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:38, 29 June 2013 (UTC)

"Eryngium heterophyllum"

Hello,

I am trying to find out information about an herb called "Eryngium heterophyllum" . There is a page in the Spanish Wikipedia on the subject, but I couldn't find anything in English. The everyday term in Spanish is "Hierba del Sapo" or roughly translated in English: "Toad herb". I have no idea what the everyday term would be exactly in English. My doctor here in Mexico prescribed it to lower cholesterol and there are some studies (in Spanish on Wikipedia) that vouch for results. I would like to collaborate this information with something in English. Can anyone help?

Thank you for your time, David Ryan Oaxaca, Mexico — Preceding unsigned comment added by 187.212.162.40 (talk) 23:45, 27 June 2013 (UTC)

We don't answer requests for medical advice. Sorry. AndyTheGrump (talk) 23:50, 27 June 2013 (UTC)

Right, no medical advice, but I can direct you to search google scholar for the latin species name. The top 4 hits are all english-language journal articles that mention the species and its uses. SemanticMantis (talk) 02:59, 28 June 2013 (UTC)