Wikipedia:Reference desk/Archives/Science/2015 September 11

= September 11 =

"Doctor of divinity" title and dubious characters?
Is there something specific about the title of 'doctor of divinity' that makes it something that anyone can apply to themselves, or buy with no restrictions? I guess so that they can call (and advertise) themselves 'Doctor '.

I keep seeing it crop up on the internet in connection to quacks, charlatans, crackpots, peddlers of new age and diet-related junk, etc. and also when people get busted for padding their resumes. -84.51.162.182 (talk) 01:16, 11 September 2015 (UTC)


 * In the U.S. at least, D.D.s tend to be honorary degrees rather than earned academic degrees (which would be Ph.D.s or Th.D.s). (Our Doctor of Divinity article says that that's not the case in the UK.)   It also points out that the honorary D.D. can be given out by any purportedly religious institution, including those as lacking in academic gravitas as the Universal Life Church. - Nunh-huh 01:28, 11 September 2015 (UTC)


 * Surprisingly enough, anyone can claim anything he likes about himself, such as that he is a lawyer or has a PhD, see Essjay controversy. What should be relevant to others is, what credentials do they provide, say a degree from Harvard, and does Harvard confirm that it granted that person that degree, and most importantly, how important is it to make sure this is true.  Even after calling Harvard, the person who presents the degree may have murdered the original graduate, had plastic surgery, stolen his credentials and be impersonating them.  (That's why serious criminal background checks are expensive and time-consuming.) Frank Abagnale had quite a career without having to go to such ends.  People can lie.  The truth as you know it is only as certain as you are willing to invest the time investigating the evidence.  There no way to avoid this. μηδείς (talk) 03:21, 11 September 2015 (UTC)


 * The fact that anyone can lie aside, having a fancy-looking-but-meaningless-certificate that says you're a doctor has value in that you are not breaking the law by doing so. Advertising your services as say, a lawyer, can invite serious civil action from your local bar association if you are not, in fact, a lawyer. There exist people who desperately want the recognition and respect that comes from a degree, but don't also want to get into legal trouble. Someguy1221 (talk) 03:33, 11 September 2015 (UTC)


 * In many jurisdictions (including the UK, and I think the US), there are several protected titles (we don't have an article), the use of which if you don't fulfil the requirements (normally entry on the relevant register, or a relevant qualification) is a criminal offence. MChesterMC (talk) 08:14, 11 September 2015 (UTC)


 * The articles would be licensure, occupational licensing, and practicing without a license, etc. Dragons flight (talk) 10:14, 11 September 2015 (UTC)


 * I did not deny or even address the fact that some fraudulent claims can be criminally prosecuted. But one still has to go through the same steps, verifying the certificate was issued by the accredited agency and so forth, all of which requires witnesses and evidence according to whatever standard of proof the court demands, and even then, one can still sometimes get away with murder. μηδείς (talk) 16:45, 11 September 2015 (UTC)


 * See also diploma mill. In a lot of countries, anyone can hand out a piece of paper calling you a Doctor of Something; what makes credentials meaningful is being awarded by an accredited institution. The accrediting body verifies that the institution actually requires you to learn something and demonstrate your knowledge before getting the credential. Looking at the article on the D.D., it appears that at least in the U.S. it's always been basically an honorary degree handed out by some religious institutions. Honorary degrees are basically a Certificate of Awesomeness that any institution can decide to give someone for whatever reason. A lot of people aren't fully aware of this (and it's true that legitimate universities don't hand out honorary degrees to just anybody), so it's an easy avenue for charlatans who want to display an impressive-sounding title. It's worth noting that an honorary doctorate is not generally viewed as giving you the right to legitimately call yourself "Doctor", and honest people with only honorary doctorates won't do it. However, outside of specifically implying that you are a medical doctor, there generally aren't laws prohibiting it, so you won't get thrown in jail for it, which is why frauds like to do it. --71.119.131.184 (talk) 06:50, 11 September 2015 (UTC)


 * A notable recipient of an honorary doctorate of divinity in the UK was Northern Ireland politician, Ian Paisley who received one from the Bob Jones University in 1966. He liked to be addressed as "the Reverend Doctor Paisley" and as far as I know escaped any legal sanction for it. Alansplodge (talk) 17:09, 11 September 2015 (UTC)

why was this suicide of the Germanwings Pilot needed for the airlines, to make airplanes more secure against suicide pilots?
Why was the flight of MH370 not the point, to make airplanes more safe ? Why was EgyptAir 990 not the point, to make airplanes more safe against suicide ? Why was Silk-Air-Flight 185 not the big point to make airplanes more safe against suicide-kamikaze--pilots ? it is fact that in the 4 flights what I have told you, the copilot or the pilot have been alone inside the cockpit with closed doors. I don´t understand this point why the Germanwings crash had become the big point if there had been yet more than 7 different suicide pilots yet in the civilian airlines, and the airlines have only watched or demented that there have been any suicide pilot (for example the Egyptian airlines) --Motorolakzrz (talk) 03:05, 11 September 2015 (UTC)


 * This was hatted as being a request for opinions, predictions, or debate, but it isn't asking for any of those, so I've reopened it. But let's keep the responses factual, please.  For example, reports on different airlines' or governments' response to the issue of pilots committing suicide and taking the passengers with them.


 * I have just one fact to add myself, which is that we don't know what happened to Malaysian Airlines Flight 370; there are only theories. Without evidence clearly confirming a pilot suicide, decision-makers are not likely to respond as if it was known to be one. --65.95.178.150 (talk) 04:11, 11 September 2015 (UTC)


 * It's worth noting that in the case of EgyptAir Flight 990, Egyptian authorities were heavily invested in denying what had taken place. In the case of SilkAir Flight 185, the flight data recorder was disabled prior to the crash, so no one is entirely sure what occurred. Without knowing how the pilot brought down the plane in that case, it's hard to make policy changes that would prevent it. Presumably the data recorder was shut off by cutting power, but that is impossible for modern cockpit voice recorders at least, as they contain an internal battery to power themselves in the event of an electrical failure. This design change was made simply to make the system more robust, but happens to make it harder for suicidal pilots to conceal their crime. Germanwings Flight 9525 is different for several reasons. It was the only crash of a large airliner causing many casualties that all air safety organizations agree was caused by pilot suicide. Also, it was the first of even the possibly-pilot-suicide incidents (disregarding those involving small planes) to occur after the introduction of difficult-to-open doors for the cockpit. Prior to the September 11th attacks, it was not difficult to force the cockpit door open. Afterwards, new doors were installed on most large airliners that essentially made entry impossible with the tools that may be likely to be found on a plane. The pilots enter and exit the cockpit typically using a code on a keypad, but on the cockpit side of the door is a manual lock that cannot be opened from the main cabin. So the very safety mechanism put in place to prevent hijackers from taking the cockpit prevented the pilot from saving the plane from the suicidal copilot. That's a problem that never existed before, and that's why it's such an issue now. Someguy1221 (talk) 04:39, 11 September 2015 (UTC)


 * It is worth noting that even before Germanwings 9525, US regulations already required that at least two people be present in the cockpit at all times. If one of the pilots needed to leave, then a flight attendant was supposed to stay in the cockpit until he returned.  While not entirely fail-safe, the two person requirement does make it harder for a single person to completely seize control.  This was one of the rule changes that Europe rapidly adopted after the Germanwings tragedy.  Dragons flight (talk) 15:51, 11 September 2015 (UTC)


 * Frankly, pilot suicides in commercial aircraft are so rare as to be a rounding error. There are tens of thousands of commercial flights every day. Plane crashes, whether intentional or not, are rare but dramatic, so they get way more attention than all the other things that kill many more people. So it's worth asking whether there is even a problem that needs addressing. As Someguy1221 notes, kneejerk "solutions" can actually make things worse. --71.119.131.184 (talk) 07:23, 11 September 2015 (UTC)


 * The German and the European copied some to the American safety regulations after 9/11. Differing to the original, these copy failed to cover the scenario one of the pilots to become a mental bomb himself. Flight 4U9525 paid the price for the improper designed national regulations. The financial situation of the pilot was not brought to the public. There are huge costs to become a pilot. The paid wages of the airline inside the enterprise was a small note on the news. A complete situation was not reported to the public. The airline updated the internal instructions immediately to cover the failure of the national regulations. -- Hans Haase (有问题吗) 15:30, 11 September 2015 (UTC)


 * What makes you think they are more secure now? Do you think a flight attendant that won't sit in the pilot seat can stop a pilot from creating an unrecoverable attitude?  Or even prevent a crash on landing?  Nope.  It's just like the tour bus in the Alps - if the driver decides to drive over a cliff or into a bridge abutment or into an oncoming tractor-trailer - ther is no stopping it.  Being 9/11, remember that the passengers overpowered the hijacker but not before he put it in an unrecoverable stall/spin.  The corrections taked are to precent the cabin from being locked but it does little to prevent a suicide.  Makes people feel better though.  Maybe the view is better from the front but the result is the same.  If they actually did come up with a way to prevent suicides, there is still the ability to fly a tiny Cessna into a fully fueled and loaded airplane in line for departure or at the gate.  --DHeyward (talk) 16:21, 11 September 2015 (UTC)


 * Are airplanes really vulnerable to that? I'd have thought they'd be designed to try to limit the scope of such a disaster... Wnt (talk) 21:34, 11 September 2015 (UTC)


 * Yup - in fact airliners are more aerodynamically unstable than single engine Cessnas since the instability makes it more fuel efficient which is more important in airliners. Center of gravity and center of lift determine inherent stability and single engine trainers are designed for stability over performnce. See Air France Flight 447 for a pilot induced stall/spin (accidental).   They have a lot of sensors to tell the pilot something bad is about to happen but ultimately the pilot can fly it into a stall/spin.  Large passenger jets lack the rudder authority to recover and virtually any stall will crash the plane.  Asiana Airlines Flight 214 is crash on landing and that airplane has autoland and autothrottle capability (and in both accidents, the pilots wanted to live, so imagine one that didn't.)  American Airlines Flight 587 shows what happens when the rudder is used too much (it's the essential component for stall/pin recovery and aggressive use ripped it off the airplane and it crashed on takeoff.)  --DHeyward (talk) 11:12, 12 September 2015 (UTC)


 * Actually, aviation is treated like magic. Even though it's safer than driving (and much safer than horseback) any improvement is attacked by lawyers.  There's nothing fancy about a cessna.  The engines are based off of 1930 tractor technology and the spark plugs are fired by magnetos.  Aviation fuel for those engines still need lead in the fuel.  AvGas is 100 octane low-lead (jet fuel is essentially diesel, though).  The Cessna 4 cylinder engine at 180 horsepower costs $50,000.  The reason why technology is so slow and the cost so high: lawsuits and liability.  Electronic fuel injection is new.  For redundancy, each cylinder has 2 spark plugs - but even though a modern car engine is more reliable, they stick with the old because anything new is always blamed.  Even electronic ignition in some of the "cutting edge" airplane engines is generally used on only one of the spark plugs.  Magnetos fail all the time, too which is why there are two but they won't move away from the known quantity.  --DHeyward (talk) 11:38, 12 September 2015 (UTC)


 * Is flying always safer than driving ? How about if you measure by hours, and compare a single engine plane flying over mountains with a large, safe car ? StuRat (talk) 22:29, 13 September 2015 (UTC)


 * Sounds like a classic case of tombstone mentality. StuRat (talk) 21:35, 11 September 2015 (UTC)

Seawater leaking between the plates
How much would sea level fall in 1 year if the water that lubricates the subduction zones and goes to the mantle wasn't recycled (presumably by volcanos?) Sagittarian Milky Way (talk) 04:05, 11 September 2015 (UTC)


 * The inside of the Earth is not a big empty hole into which water can pour. As you go deeper, you will find greater pressure from the overburden of soil and rock layers above.  That pressure affects everything - all the space between solid material would be filled with either fluid or gas, and it would be under a lot of pressure.  It doesn't matter if the fluid is water, brine, mud, petroleum, natural gas - it's still getting squeezed by the material on top of it and around it.  That pressure is so high that it can maintain hydrostatic equilibrium, and in many cases, the pore pressure is higher than equilibrium, which means that liquid actually moves upward, against gravity - it doesn't fall downward!  In its most dramatic form, the fluid gets squeezed upward by the rock with such great force that it forms a gusher.
 * Nimur (talk) 06:24, 11 September 2015 (UTC)


 * Given that even the fastest plates only move a few inches per year, the drop couldn't be more than a tiny fraction of an inch. Looie496 (talk) 13:07, 11 September 2015 (UTC)


 * Am I wrong then thinking that the H2O goes below the crust? I thought I heard that this is why Cascadia could have a bigger maximum possible earthquake than San Andreas-type faults. Even if it's a tiny fraction of an inch it could add up to something in millions or billions of years. As for divergent faults, I think it just boils and rises, right? It doesn't even seem to affect the thermohaline circulation in any meaningful way. Sagittarian Milky Way (talk) 00:09, 12 September 2015 (UTC)


 * The seismic moment and, therefore, magnitude of an earthquake is related directly to the surface area of the fault that slips and the amount by which it slips. The low-dipping thrust faults that form the upper parts (the bit within the seismogenic layer) of the plate interface on a convergent boundary are the largest areas of potential earthquake rupture on the planet. Strike-slip faults like the San Andreas rarely get much over M8.0, because the steep fault involved only rupture within that seismogenic layer and are normally only about 15-20 km deep, and this limits the total rupture area. In comparison, the upper parts of megathrust faults, like the Sunda megathrust have dips of a few degrees only, so that a much greater down-dip extent of the fault surface is available for rupture, giving M9+ events for the largest. Regarding the water that goes down a subduction zone, most of it is chemically bonded to clay minerals. On heating this becomes driven off by the great pressures involved at depth and some of it ends up hydrating the mantle of the overriding plate, which in turn leads to partial melting and then to volcanic arcs being developed above. Mikenorton (talk) 17:20, 13 September 2015 (UTC)
 * You may also wish to read Geothermal gradient. At a depth of, say, five miles below our Earth's surface, the ambient temperature is nearly always greater than the boiling point of water.  This does not mean there is zero water: the conditions are complex, and the pressure is very high, and the free flow of material can be impeded by layers of rock above and below; all of this adds complexity to the answer.  However, the water that you would find will typically be chemically bound to minerals as a hydrate, exactly as User:Mikenorton described.  It would be exceptional to discover liquid water, or even water vapor, at very great depths below Earth's surface.  Think about your chemistry lab experiments where you heated some inorganic material in the presence of steam: in most cases, almost all of the water evaporates and escapes as steam very quickly; but sometimes, the water chemically binds to other material; and in some cases, especially at very high temperature and pressure, the oxygen and hydrogen dissociate and then chemically interact with some other reactant, forming new material that is not water anymore.  If you were to look inside Earth at a depth of a hundred kilometers, where the ambient temperature is thousands of degrees and the pressure is so high as to be unfathomable in ordinary terms, the type of reaction in which molecular water cannot exist for long exemplifies the kind of chemistry you would find.
 * For an even more tangible example, re-read our article on hydrothermal vents: at the seafloor, seawater will flash-boil into supercritical steam when it contacts these very hot areas - and that's not even inside the lithosphere! We also have a well-referenced article on hydrothermal circulation, including information about water inclusion deeper inside Earth's crust.  Water doesn't want to stay at such high temperature and pressure - eventually, heated steam goes up!
 * Nimur (talk) 15:08, 14 September 2015 (UTC)
 * Thanks guys. I was getting a bunch of poorly remembered things mixed up, like the heat and pressure "lubricating" the deep fault by making it too plastic for earthquakes and the water doing something unexpectedly deep. Sagittarian Milky Way (talk) 01:55, 15 September 2015 (UTC)

Is There a Name or Remedy for This Sleep Condition?
This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis or prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page. --Dragons flight (talk) 10:06, 11 September 2015 (UTC)
 * OK, is there a name for the sleep condition, whereby one spends all night (subjectively) reworking the mathematical or problem solving tasks that one did the previous day, and consequently wake up exhausted? Greglocock (talk) 21:08, 11 September 2015 (UTC)
 * See insomnia. -- Jayron 32 04:27, 12 September 2015 (UTC)
 * Thank you for precisely nothing. That article adds zero to my description. Greglocock (talk) 09:25, 12 September 2015 (UTC)
 * You asked for a name for the condition, not for adding something to the description. Nil Einne (talk) 16:10, 12 September 2015 (UTC)
 * Yes I did. The person who asked the zealously hatted original question had already identified it as insomnia. Is this refdesk entirely taken over by pedantic twits and idiots? On current evidence, apparently. Greglocock (talk) 18:39, 12 September 2015 (UTC)
 * No, but it does appear that it is trying to be taken over by people who's main purpose is to call people names and be incivil and rude. -- Jayron 32 19:04, 12 September 2015 (UTC)
 * The link provided, insomnia, gives a general description of the inability to sleep, together with some causes. Nowhere does it describe or provide a term for the specific symptom that was posted: "reworking the mathematical or problem solving tasks that one did the previous day..." The question appears to be unanswered. Akld guy (talk) 23:52, 12 September 2015 (UTC)
 * The original question was deleted. You asked a new question, for whatever reason under an old subject heading. You can't fault people for answering the new question that was asked. The old question is deleted, and so is now irrelevant to the RD proper. If you feel it should not have been deleted, you're welcome to discuss that in WT:RD or somewhere else appropriate. Nil Einne (talk) 12:54, 13 September 2015 (UTC)


 * Would you kindly state who your post is directed to? Because you took the trouble to insert it directly below mine, it looks like you're criticizing me for posting an irrelevant response. Furthermore you have given the impression that I was the OP of the original (deleted) question, but I was not. Note that all comments that appear have been made on the basis of the revised question, according to their timestamps. Nothing is irrelevant here. Akld guy (talk) 23:32, 13 September 2015 (UTC)
 * No I took the trouble to WP:indent my post correctly. It was directed at Greglocock who's reply my reply was clearly indented at, and was posted below because Jayron32 had already replied to Greglocock at the correct indentation level, a reply which you replied to (or at least I assumed so). Since this is the second time you've been confused by good indenting practices, I strongly suggest you take a read of the relevant guidelines, essays (like the earlier one) and other pages to avoid such confusion in the future. I appreciate our norms may be somewhat different from unthreaded forums and the like, but they are the norms here and understanding and hopefully following them to as much as allowed by the discussion avoids confusion. This was actually a case where indentation worked well, or would have if you hadn't been confused. I saw your response, but decided it was largely irrelevant to my comment, so didn't see the need to address it at all in my reply to Greglocock. So there was no need to wonder whether I should indent my reply to your comment but also address Greglocock, or indent to Greglocock's comment, but briefly mention your response. As can happen in more complicated cases. I did consider replying to your comment seperately as well. If I had done so, I would have done so at the correct indentation level to reply to you, and probably would have offered sources like, which mention possible causes of insomnia to include "A general feeling of being revved up or overstimulated", "Excessive worrying about future events" and "Getting caught up in thoughts about past events", one or more of which will probably apply to people thinking of mathematicial problems etc. But I chose not to do so since I didn't regard it as that important. And I stand by my comment. Greglocock posted a question, someone offered an answer to their question as posed. Greglocock then complained people weren't answering their question because "The person who asked the zealously hatted original question had already identified it as insomnia". But as I stated, the deleted (not hatted) original question is irrelevant to the question Greglocock asked. To be clear, insomnia is relevant to their question as posed, and even if our article doesn't clearly state thinking of mathematical problems etc as being a possible cause of insomnia, other sources do give a broad overview of conditions underwhich thinking of mathematical problems comes under. In fact, unlike you, Greglocock seemed to acknowledge their question was in fact answered by insomnia since they specifically said the condition had already been identified as insomnia. Being already identified as insomnia wasn't true for the reasons explained, but implies an acknowledgement that insomnia is part of the answer. Not sure why you think I thought you were the OP of the original question. Since I wasn't addressing you or your response in my reply, it didn't come up, but I never thought so. And for the record, I didn't think Greglocock was the OP either. I knew they weren't although it was largely irrelevant to my comment who exactly was the OP. (Well it would have made a small amount of sense for the OP to ask a new question under an old subject heading when their question is deleted unlike Greglocock asking so. But it's generally that such questions should still be deleted. So it's not completely irrelevant.) Nil Einne (talk) 05:13, 14 September 2015 (UTC)
 * Since you weren't replying to me but to Greglocock, why did you insert your comments under mine? According to the indentation essay you referred me to, you should have placed them under Jayron's comment at 19:04, 12 September, with the same indent as his. The casual reader who knows nothing of proper WP indentation (and it is a sorry substitute for typing the name of the user being responded to) would jump to the conclusion that I was the target of your remarks. Such readers are not interested in where the indentation falls, or spending the time scrolling up the page to match one indentation with another. Akld guy (talk) 07:36, 14 September 2015 (UTC)


 * Others have been asking the same question, quite a few responses here: http://ask.metafilter.com/217726/Pure-math-isnt-even-fun (including a link to a study it seems) less helpful: http://www.quora.com/Can-doing-mental-mathematics-cause-insomnia Ssscienccce  (talk) 04:40, 13 September 2015 (UTC)
 * Sleep apnea. See the symptoms. --VanBuren (talk) 07:11, 13 September 2015 (UTC)
 * That doesn't describe the snippy OP's alleged symptoms. It sounds more like some kind of anxiety, as was originally suggested upon the original question. This entire section should be zapped. ←Baseball Bugs What's up, Doc? carrots→ 05:16, 14 September 2015 (UTC)
 * So zapped, but I left the quora link visible. μηδείς (talk) 19:29, 14 September 2015 (UTC)

Newly discovered hominin species Homo naledi
News stories have described discovery of this hominin species via fossil remains in a chamber in a cave which is very difficult for modern cavers to reach: a climb through very small passages as narrow as 20 cm, in total darkness, with risk of falls.The Wikipedia article is Homo naledi. One journal article, http://elifesciences.org/content/4/e09561 says the remains may have been intentionally deposited as a cultural practice. 1)How long ago is "3 Ma" and is Ma part of some SI unit system? 2)How could the Homo naledi have carried remains to the chamber in total darkness over an arduous route? The article says there does not appear to have been an easier route in the past. If they carried torches, wouldn't there be soot deposits or preserved carbon deposits from torches? I believe there are clear instances in caves of soot from torches being preserved for a long time on cave ceilings, sometimes by deposition of flowstone. There was flowstone in this cave. 3)What types of radiological dating might be possible? 4)Might there be DNA recoverable from teeth or bones? 5)When did hominins start using torches? Thanks. Edison (talk) 16:12, 11 September 2015 (UTC)


 * To answer one part - Ma=Mega-annum, so 3 million years ago. Mikenorton (talk) 16:21, 11 September 2015 (UTC)


 * 1) Ma = 1 megaannum, or million years. See Year.  2) Some of these questions are not fully answered even by the scientists.  Though, if modern Humans got there, wouldn't a smaller hominin, more used to climbing in a variety of environments, have also been able to get there?  That's my (WP:OR) answer.  3) Not sure.  The methods listed at Radiometric dating list only methods whose effective time scales are too short (radiocarbon dating, which is not effective past a few thousand years) or too long (methods used to date rocks in the billions-of-years range, whose tolerances are to wide to be useful here).  Possibly there are some that article doesn't cover.  4) Probably not.  DNA degrades over time; Ancient DNA indicates that the oldest DNA to have been identified so far is an impressive 400,000 - 500,000 years old, still an order of magnitude too short a time frame for our 3 million year old hominin.  5) Control of fire by early humans indicates the earliest use of fire by human ancestors was 400,000 years ago, again an order of magnitude too recent.  -- Jayron 32 16:31, 11 September 2015 (UTC)


 * As to the question "is Ma part of some SI unit system?": No, it isn't. "M" for mega is part of SI, but the only SI units of time are the second and its prefixed variations.  So in SI you can have megaseconds (although in practice nobody outside of science fiction seems to use them), but not megayears.  The minute, hour, and day have the status of "Non-SI units accepted for use" with the SI, allowing things like speed measurements in km/h to be legitimate; but the year does not have that status either.  See the SI standard here, in particular table 6 on page 32 (PDF page 37) for the non-SI units. (This is the US edition of the standard, but any edition will have the same content.) Scientists who want to work in megayears have apparently settled on the symbol "Ma", but the "a" doesn't come from the SI. --65.95.178.150 (talk) 18:12, 11 September 2015 (UTC)


 * That's interesting. I thought perhaps Ma's usage was influenced by Mya (i.e. Million Years Ago), which to my recollection used to be something of a standard. 64.235.97.146 (talk) 20:15, 11 September 2015 (UTC)


 * The question of how the bones came to be in such an inaccessible spot is probably best answered by the 3Ma thing. Over the course of millions of years, caves can collapse, be filled in by stalagmite/stalagtite growth - or be expanded by erosion from water flow - so it's very hard to say how they might have gotten into this space.  It's unlikely that they'd have brought bodies there through the tortuous route that the researchers went through.  But clearly the full extent of the cave system is still unknown otherwise this small cavern would have been known about long ago.  There is still the possibility of a much more direct route from the surface, either now or in the distant past.  It's even possible that a small group of Neledi entered this complicated cave system, got lost in the darkness and wound up dying of starvation right there.  But this is still a very new find - we'll know a lot more when it's been more fully investigated. SteveBaker (talk) 18:22, 11 September 2015 (UTC)
 * The paper linked (which may not be at the level of a respected peer-reviewed journal) says there had been no other entry route, and that the burial chamber and its approach route had been in darkness all that time. What little hominid would crawl down into a crevice not knowing if there was a pit ahead? One could speculate that someone who is hiding from an attacker or threat of some kind might crawl into some random tight spot and lose track of how to get out. But there were infants, youths, and adults. The infants would have had to be carried or dropped. There were no evident fractures from near the time of death. Edison (talk) 00:23, 12 September 2015 (UTC)
 * The thing is - they must have gotten in there somehow. The paper simply dismisses all of the possibilities - which is an unreasonable standpoint.  However, these  creatures evidently did get there.  So one of the assumptions must be incorrect.  By far the most likely error is that their bold assertion that there could not possibly have been an older and much easier entrance.  3 million years is a very long time - even by "geological time" standards.  I don't see how they could possibly tell whether an older entrance had caved in...been filled with debris and then covered by layers of stalagmites - which in turn eroded away - which collapsed again...who knows?  Over millions of years, that cave system must have gone through a lot of changes.   It's going to take geologists, ground penetrating radar and a LOT of additional science before we'll really know. SteveBaker (talk) 05:33, 12 September 2015 (UTC)
 * Steve, the paper (which I've carefully read, along with the accompanying –/e09560 which describes the bones themselves in detail) does not dismiss all of the possibilities. It suggest that the "extended-period death trap" and "one-time disaster" (my terms) scenarios seem unlikely but have not yet been excluded, and the "deliberate deposition over time" seems most likely but is not yet proven.
 * That some then-easy route has been overlooked is belied by the extremely detailed geophysical survey of the area that has been ongoing for more than 2 years. You may find more details via John D. Hawks' Weblog which, now that the papers have (just) been published (on 10 Sep 2015), will be free to carry more discussion about all this. (Hawks is the second author on the "Bones paper".) {The poster formerly known as 87.81.230.195} 185.74.232.130 (talk) 14:33, 14 September 2015 (UTC)
 * This video called "Dawn of Humanity" is an interesting external link found at the Homo naledi article. Bus stop (talk) 07:01, 12 September 2015 (UTC)
 * Perhaps there was a natural hazard. It may have been very rare that Homo naledi plunged to their death. But if the cave system was used over millennia, accumulation of remains is possible. It is not hard to imagine a smooth sloping rock surface covered in algae and dripping water creating the hazard that leads to Homo naledi plunging to their death. The cave system in a slightly different configuration may have served some important purpose to the Homo naledi and the natural hazard may have been avoided most of the time. There may have been a tradeoff between the benefits (I'm not sure what they would be) of the cave system and the occasional deaths due to this naturally occurring hazard. Bus stop (talk) 11:35, 13 September 2015 (UTC)
 * Logical, except that the H. naledi remains are found almost entirely in the innermost, least accessible chamber (the Dinaledi Chamber): there's only a couple of traces of them them in the preceding, bigger chamber (the Dragon's Back Chamber) and the passages leading from it back to the (only) entrance. The scientists seem fairly sure that the general configuration of the Rising Star Cave hasn't changed significantly since before the era of these depositions.
 * On a different note, are we going to wind up calling this species "Dinner Lady Man"? {The poster formerly known as 87.812.230.195} 185.74.232.130 (talk) 14:43, 14 September 2015 (UTC)


 * The study authors ruled out falling to their death as none of the remains had evidence of major bone fractures occurring at the time of their death, as one might expect if their death was caused by falling a great distance onto a hard surface. I suppose they could have fallen without breaking bones, somehow gotten stuck, and then starved to death.  Hopefully the remains may reveal enough about cause of death to eventually say whether they died in the cave, or if their remains were intentionally disposed of in the cave after death as the scientists have been speculating.  Dragons flight (talk) 12:56, 13 September 2015 (UTC)


 * The authors didn't "dismiss all possibilities" as user:SteveBaker said. Under the heading Deliberate disposal it says "In the deliberate body disposal hypothesis, bodies of the individuals found in the cave would either have been carried into, or dropped through an entrance similar to, if not the same as, the one presently used to enter the Dinaledi Chamber. If individuals were dropped either whole or in part into the present entrance chute to the chamber, then physical entry would not be required. None of the bone elements studied shows evidence of green fracture (Supplementary file 2), indicating lack of trauma" In New Scientist here but you need to subscribe they give a diagram of the cave system and the two very narrow points are the 12 metre vertical shaft that they are thought to have dropped the body parts down and a short horizontal squeeze they looks like about 2 or 3 metres long - which is much less of a problem to get through. The main question, that they don't answer, is how they found their way in the dark - torches seem to be the only possibility. Richerman    (talk) 14:48, 14 September 2015 (UTC)
 * If the cave served an important purpose in life, unrelated to death, familiarity with its dark chambers is a possibility. The cave would be cooler than the outdoor temperature. Perhaps it served as sleeping quarters and a place of retreat and possible recuperation after illness or injury. Death in such close quarters would require removal of the dead bodies. This would not necessarily be for our present understanding of burial for ritualistic purposes. Even in darkness the removal of the dead to a more distant chamber may have represented a defensible practice. Bus stop (talk) 16:20, 14 September 2015 (UTC)

Ageometre
Hello, I looked at myself/body today, after a long time; 3-4 years later. I was quite upset with the thought, "Queen Elizabeth looks better than me". So I was wondering if there is a way I could check my current age/body deteoration level. -- Space Ghost (talk) 19:29, 11 September 2015 (UTC)


 * See body image. The opinion you have of your own health and/or attractiveness can be almost entirely unrelated to your actual healthfulness and/or attractiveness, and instead be more a factor of internal psychological processes.  That is "How I think about how I look" is more related to "How I think" than "How I look".  So, whether or not you are "detereorated" as you note isn't really something you can actually trust yourself to be able to judge about yourself.  -- Jayron 32 19:35, 11 September 2015 (UTC)


 * Note that you only ever see the Queen fully clothed, in full make-up, and maybe with a soft focus lens, so any comparison is bound to be flawed. StuRat (talk) 21:39, 11 September 2015 (UTC)


 * My eyes are soft focus lenses. A woman up ahead is surprised that I like her, then it turns out she's very attractive from afar and in the past and is so many decades older than me that I'd have never looked for a second if I had my glasses. Sagittarian Milky Way (talk) 00:20, 12 September 2015 (UTC)


 * My guess was right guys. I measured myself today, shrinked 5-7cm lengthwise and lost 6 kg weightwise. Isn't there a way to analyse 'how many miles have I done with my life'?. You know, like the cars, what you see in the dialogue box... -- Space Ghost (talk) 19:27, 12 September 2015 (UTC)


 * This is too close to medical advice that Wikipedia can't give. I doubt you can guess your lifespan by reading a website about what you look like (though of course there are some ways to get an idea from known risk factors).  A physician might be able to make some guesses, and could look for obvious issues like dehydration or pathological reasons for weight loss or height reduction.  We can't substitute for that. Wnt (talk) 15:33, 13 September 2015 (UTC)
 * There is the concept of biological age, which can be determined in various more or (usually) less reliable ways. You can find plenty of quite bad online quizzes purporting to compute your biological age. A good fitness club may also do some tests when you join it. --Stephan Schulz (talk) 21:40, 13 September 2015 (UTC)

Jayron 32, StuRat, Wnt, Stephan Schulz:

Hello, sorry for the delay, I've been away from my PC.Festival (Eid) is coming soon, so I had to get ready... Thanks friends. Take care...

P.S. for Wnt: I'm aware of the medical advice issue, believe me, I would be the last person who'd wish for WP to shut down... I thought I was clear enough, anyway, I'm happy that you guys at least notified what the cause(s) is and or where I could go in order to mitigate it. Next time I'l try my best to be clearer; probably request for a list of causes and or where I could go to mitigate it...

Space Ghost (talk) 23:17, 15 September 2015 (UTC)

Is soda water (water+CO2) is non healthy?
Is there any evidence or evidences about the influence/s of drinking soda water on the body or on the healthiness? 37.73.214.166 (talk) 22:44, 11 September 2015 (UTC)


 * Well, carbonation plus water tends to produce carbonic acid, which, like any acid, tends to damage the surface of teeth and thus promote tooth decay. StuRat (talk) 00:56, 12 September 2015 (UTC)


 * Do you have a reference for that claim? I'm not saying you're wrong.  I'm saying that you need to provide references, since this is the reference desk.  If you cannot provide references to back up what you say, please refrain from answering and allow people who are willing to do so to answer instead.   -- Jayron 32 02:09, 12 September 2015 (UTC)


 * Although Wikipedia is not a reliable source, our article on carbonated water discusses this, but says that the acid is on par with apple juice. Ian.thomson (talk) 02:16, 12 September 2015 (UTC)


 * Yes, Jayron should have read the link and saw that the opening paragraph supports my claim that carbonated water contains carbonic acid. If he still doubts the claim, then his argument is with the authors of that article, and not me. StuRat (talk) 02:30, 12 September 2015 (UTC)
 * As I said, though, Wikipedia is not a reliable source. The issue is not so much doubting the claim as the refdesk providing actual references. The carbonic acid article mentions nothing about tooth decay.  That may be a "sky is blue" claim, but it still requires a source to explain what shade and hue of blue it typically is.  Ian.thomson (talk) 02:34, 12 September 2015 (UTC)
 * carbonic acid contributes little to the acidity of soda. Carbonic acid alone does not contribute much to dental erosion, Fizzy drinks also have carbonic acid that comes from dissociated carbon dioxide, but it is too weak to have any affect on teeth, carbonation of drinks may not be an important factor per se in respect of erosive potential, However, carbonic acid isn't particularly acidic compared to many of the other acids you'll find in sodas -- phosphoric acid, for instance -- and isn't implicated in damage to teeth, explains Dr. P. Moynihan in a 2002 article in the "British Dental Journal." This is partly because carbonic acid is relatively weak, and partly because it decomposes so quickly. -- Jayron 32 03:58, 12 September 2015 (UTC)
 * This is why we need to use outside sources. Ian.thomson (talk) 04:07, 12 September 2015 (UTC)
 * I don't think that exposure for a few minutes in 24 hours to carbonic acid makes a big difference. After all, carbonic acid is unstable, therefore it has no lasting effect on teeth. Tgeorgescu (talk) 19:12, 13 September 2015 (UTC)


 * Soda water contains Dihydrogen Monoxide, which (as DHMO.org, Lock Haven University, and even Snopes note), is used as a fire retardant, industrial cleaner, and in the distribution of many pesticides. Breathing even small amounts of the stuff can be lethal. Ian.thomson (talk) 02:16, 12 September 2015 (UTC)
 * It also is highly addictive - apparently withdrawal of DHMO is universally lethal not only in controlled tests with lab animals, but also, anecdotally, in humans. --Stephan Schulz (talk) 07:17, 12 September 2015 (UTC)
 * Agree with the above. The DEA should stamp down hard on the abusers of DHMO, especially those who have been adulterated with CO2. The government should also consider accelerating the development of finding a way to neutralise this type of  hazardous waste. By my own experience I have found that by diluting it 50/50 with a good malt whiskey makes it benign but I can't offer any references to back up my Original Research.--Aspro (talk) 11:35, 12 September 2015 (UTC)
 * Do you have a source for that soda water contains Dihydrogen Monoxide? Do you have a source for that soda water is also highly addictive?37.73.212.102 (talk) 12:37, 12 September 2015 (UTC)


 * According to our own guidelines, wikipedia is an acceptable source for answers in the reference desk. Even your own knowledge may be acceptable, but you should make it clear that that is what you are using.
 * For some types of questions, answers that contain references are more useful than those which don't. For those questions, make a serious effort to locate a Wikipedia article or an outside reliable source that supports your assertions, and include a link to it in your answer. You may know that your answer is correct, but a reader has no way to judge how reliable your information is unless you specify your sources. Even if your only source is, say, your own recollections from your school days, it is very helpful to state so in the posting. If there is a Wikipedia article that should answer a question, but doesn't, make this clear; you don't want to send a questioner on a wild goose chase, and you do want to let other editors know that the article needs improvement. 109.151.143.201 (talk) 18:54, 13 September 2015 (UTC)

Is honey better than sugar (From a health perspective), and if it is what the reason
37.73.214.166 (talk) 22:50, 11 September 2015 (UTC)


 * Define "better". ←Baseball Bugs What's up, Doc? carrots→ 23:14, 11 September 2015 (UTC)

Thank you, I edited the title and added "From a health perspective". 37.73.214.166 (talk) 23:33, 11 September 2015 (UTC)


 * You might want to define "sugar", too, as that includes many different types of sugar. I would guess you mean sucrose, AKA "table sugar".  Honey does have anti-bacterial properties, but those might not survive in the stomach.  Still, it might affect the bacteria in the mouth, although it might just as well kill off good bacteria as bad. So, it's hard to say.  Nutritionally, though, it may include trace elements and such that are somewhat better than pure sugar. Of course, there are also less refined forms of sucrose, such as molasses, which may be even healthier.  StuRat (talk) 01:00, 12 September 2015 (UTC)


 * According to whom, for any of your claims? Do you have an references for any of that.  Please don't try to defend yourself by claiming that I'm saying that your wrong.  I'm not.  I'm saying that your claims need references.  Please provide references, since this is the reference desk, as to the health differences between honey, sugar, molasses, and all the rest you seem to be claiming.  -- Jayron 32 02:07, 12 September 2015 (UTC)


 * Many of those claims are in the articles I linked to, as in the last time you complained. Just like complaining, don't you ?  If your only purpose in life is to complain, maybe we can find a better forum for you. StuRat (talk) 22:35, 13 September 2015 (UTC)


 * For a start the sugar content of honey is roughly a 50/50 mix of glucose and fructose, the letter is a bete noire of the trendies. Greglocock (talk) 04:44, 12 September 2015 (UTC)


 * Reference please? -- Jayron <b style="color:#090">32</b> 04:47, 12 September 2015 (UTC)


 * www.honey.com%2Fimages%2Fdownloads%2Fcarb.pdf Greglocock (talk) 05:54, 12 September 2015 (UTC)
 * Honey is not recommended for children under one year of age, as it can lead to infant botulism (though not necessarily the most common cause). Otherwise, it's just a mixture of flavored sugars.  Acroterion   (talk)   02:13, 12 September 2015 (UTC)


 * Having a balance natural diet is more important with everything eaten in moderation. The British National Health Service has a advisory about fructose which is quite comprehensive. .--Aspro (talk) 11:48, 12 September 2015 (UTC)
 * Where's the advisory? You linked to what appears to be NHS discussion surrounding one particular study about High fructose corn syrup which gained media attention rather than an "advisory about fructose which is quite comprehensive". Nil Einne (talk) 15:06, 12 September 2015 (UTC)


 * It is an advisory because it is not stating categorically the one should not consume large quantities of fructose. It is simple pointing out that an associations have been noted and gives the background. So, it an advisory It is an advisory because it is not stating categorically the one should not consume large quantities of fructose. It is simple pointing out that an associations have been noted and gives the background. So, it an  advisory (High fructose corn syrup contains a lot of fructose and one does not have to point out that the sky is blue).--Aspro (talk) 20:56, 12 September 2015 (UTC)


 * Here's an article from Huffington Post where they interview a nutritionist about the differences between honey and (processed) sugar. Googling the phrase honey sugar healthy brings up many hits, including ones arguing on opposite sides to give you a more nuanced view. Here's another one that looks pretty good. 99.235.223.170 (talk) 12:57, 12 September 2015 (UTC)
 * See this published yesterday in the Washington Post, which indicates no advantage to honey.   Acroterion   (talk)   15:21, 12 September 2015 (UTC)


 * Basically honey is inverted sugar (ordinary sugar split into glucose and fructose), with a few water and small amounts of other substances (see e.g. and ). Honey is bad for teeth, see e.g. . Tgeorgescu (talk) 19:22, 13 September 2015 (UTC)


 * A more detailed analysis: . Tgeorgescu (talk) 19:32, 13 September 2015 (UTC)