Wikipedia:Reference desk/Archives/Science/2015 August 2

= August 2 =

Will the recently found debris from missing airplane MH-370 help to locate the plane?
Let's just assume that the debris found near Réunion Island is, in fact, from the missing airplane MH-370. Does that conclusion in any way help searchers to actually find the plane (i.e., the rest of the plane)? If so, how so? Or does this discovery simply tell us three basic things: (1) Yes, it was MH-370; (2) Yes, it crashed; and (3) Yes, it crashed somewhere into the Indian Ocean. Other than that very basic info (those three facts that I listed), can this conclusion (that the debris is definitely MH-370) help locate the missing plane at all? Thanks. Joseph A. Spadaro (talk) 06:10, 2 August 2015 (UTC)


 * If examination of the recovered item proves that it came from MH-370 it won't help locate the flight data recorder or the remainder of the wreckage. However, close examination of the item may provide information as to whether the aircraft struck the ocean at very high speed, such as in a steep dive, or at the sort of speed appropriate to a controlled ditching. It may also reveal whether the item has been deeply submerged before breaking free from the wing and rising to the surface, or whether it broke free before the remainder of the wreckage sank. None of these things are likely to contribute to knowledge about where the aircraft struck the ocean but they might provide a little information that the world doesn't presently have. One thing is certain - this item will be subjected to the most intense scrutiny by a lot of people trying to find out whatever they can. Dolphin  ( t ) 06:29, 2 August 2015 (UTC)


 * Can people who study waves, currents, and water paths somehow calculate a "reverse" path, to see where the debris originated?  Joseph A. Spadaro (talk) 06:35, 2 August 2015 (UTC)


 * Yes they can back calculate likely paths, aided by a zillion little rubber ducks http://www.columbiatribune.com/editorial_archive/rubber-ducks-still-floating-after-years/article_1533a1a4-f9e8-11e2-afcf-10604b9f6eda.html . More to the point any relevant wreckage at all provides confidence that they are in the right hemisphere, and not completely wasting their (my) money. Greglocock (talk) 06:40, 2 August 2015 (UTC)


 * Here is the Wikipedia article on that event, with the Rubber Ducky Toys: Friendly Floatees. Joseph A. Spadaro (talk) 07:39, 2 August 2015 (UTC)


 * Yes. But there would be many such reverse paths; and the information wouldn't show whereabouts on any of those paths the item began its languid journey towards la Reunion Is. About all such information would reveal would be a statement that the item was almost certainly released somewhere in the Indian Ocean. Even that would be useful in dispelling some of the conspiracy theories about the aeroplane being flown to a secret destination in Asia or India or China etc. Dolphin  ( t ) 06:44, 2 August 2015 (UTC)


 * On the news the other day, they were saying that studying the barnacles attached to it may help determine what depth it came from, as there are apparently different types of barnacles at different depths. The report also said that the current search area appears plausible as an area of origin. Rather large, of course. As to the conspiracy theories, that garbage most likely created false hope for the relatives of the missing. ←Baseball Bugs What's up, Doc? carrots→ 07:01, 2 August 2015 (UTC)


 * I'm not suggesting the discoveries will silence the purveyors of conspiracy theories! I imagine they will see the item discovered on the beach as incontrovertible proof that the bad guys fabricated a piece of a B777 wing, tethered it in the sea for a year to build up a few barnacles, and then deliberately placed it on a beach on la Reunion Island to mislead the world into thinking the aircraft splashed down in the Indian Ocean, and therefore stop looking at isolated airstrips in Asia, India, China etc! Dolphin  ( t ) 08:05, 2 August 2015 (UTC)


 * The finding of MH-370 wreckage in the ocean can be summarized in one quote: "They're dead, Jim." --DHeyward (talk)


 * I think that this discovery will lead to some very productive work in modelling the ocean currents and debris field. Already a second piece of flotsam (though I am sorely tempted to call it jetsam) has been discovered on the island   Previous models predicted the wreckage would turn up 4500 miles away, at Indonesia .  That article also says the plane didn't nose-dive, but descended gradually or ditched.  I feel like there are two possibilities - one, the models are wrong, or two, the search was in the wrong place all along.  It will be interesting to find out which.
 * I've definitely been inclined to follow the conspiracy ideas, and really, the wreckage sort of backs them up. Initially, I thought the plane might have been hijacked and hidden somewhere, but as ransom demands never turned up, that seemed less likely, and then the search proposed it was taken south somewhere it couldn't reasonably be expected to land.  But if the plane turns out to have gotten most of the way to Africa instead, this could be seen as the same hijacking plan, but simply running out of fuel along the way. Wnt (talk) 11:12, 2 August 2015 (UTC)


 * Your link about a second piece doesn't provide anything useful but AFAIK, there have been no other pieces found which so far where there's any real confidence they may be from MH370. There was a piece of what appears to be a suitcase or other such container which was found near the flaperon, but it had no barnacles. It's been taken for investigation but it's such a small portion and appears tattered and damaged enough that it would seem likely even if the investigators have high resolution photos of the every pieces of lugggage from all angles (which they don't), it would be difficult to reliably conclude it came from MH370. There was a Chinese water bottle and a Indonesian cleaning product bottle, who's linkage seems to me to me a major case of WTF?  Some people have suggested they burnt what appeared to be a seat, from a plane, hang glider or something else a few months ago. Not quite as bad as the water bottle and cleaning product bottle but, still since it's been destroyed it's fairly useless and there's a good chance it is completely unrelated. The same person said they found luggage which was full and similarly burnt. This seems more odd (the fact that it was full I mean as it's not something people normally just throw away if it was full of normal luggage stuff although unless it was opened it could have been full of rubbish), but it's also useless now and there's also a very good chance it's unrelated.  There was the part initially described as a door, but is now suggested to be part of a ladder, and photos have emerged it was little more than a twisted chunk of metal . (It also appearantly had Chinese writing on it which I think is unlikely on the door of a Malaysian Airlines plane, even one which was on a route to China.)  There has also been suggestion of some mysterious water bottle given to pilots to keep them awake. No idea what this is but while it is a little more unusual than some random water bottle, it's likewise difficult to reliably connect it.   The only conclusion we can make from any of the supposed debris is that it's not a good idea to assume every single piece of rubbish which came from one of the world's major rubbish dumps on to an island in the middle of said rubbish dump which has several people who's (only?) job is to go around picking up said rubbish; is from MH370. And also, now that a piece which almost definitely is from MH370 was found there, you're almost definitely unsurprisignly going to get that from the media and people on the island.  Nil Einne (talk) 15:07, 2 August 2015 (UTC)


 * BTW, on another point your link itself says the plane descending gradually was what's been predicted for a very long time. As for the ocean modelling thing, your link suggests the confidence in these predictions was always unclear. It's not that hard to find other discussions from before this finding such as which actually do have other predictions (Western Australia), and more importantly suggest every more clearly there were always great uncertainties.  Perhaps most importantly, from what I've read most experts who have looked in to it, including the Australians you refer to, seem to agree that while the find may have been a bit unexpected, it doesn't actually suggest the search area was wrong. See e.g. . So either these experts who you're relying for your conspiracy theories have all decided to get in on the conspiracy. Or they didn't and you have to also trust them when they say there's nothing in the latest finding which suggests the current predicted crash location is wrong.  Nil Einne (talk) 15:07, 2 August 2015 (UTC)


 * I should clarify that I'm not suggestion efforts shouldn't be made to identify and attempt to determine if stuff found may be from MH370, simply that it's a mistake to trust media reports about possible pieces being found since in reality probably something like 99% or even 99.9% of reports are going to be false positives at the moment. It's definitely sounding like whatever Wnt refered to above was one. Nil Einne (talk) 19:29, 3 August 2015 (UTC)


 * I heard these suggestions from an aviation expert on the news:


 * 1) Since the item is intact, that suggests the plane did not crash at high speeds.


 * 2) The outside edge of the control surface shows wear of the type expected when rapidly hitting the water, but not the rest of the flaperon. That points to it landing in the water with the flaperon down, presumably in an attempt to lose speed and survive the landing.  This all suggests a pilot trying to land safely.


 * 3) However, the flaperon being separated from the wing implies that the landing was not successful, and the plane broke up. But, if it crashed at low enough of a speed, there might have been survivors.  If so, the lack of bodies suggests they either didn't survive for long, or, more ominously, were picked up and hidden away.


 * As for my own thoughts, I suspect a conspiracy to kidnap a planeload of people and ransom them back. There would have been a boat there to pick them up, but apparently the landing was botched and everyone died, so no ransom demands were ever sent.  I'd look into any boats in the area at the time, even those with a valid reason, like fishing boats.  StuRat (talk) 23:33, 2 August 2015 (UTC)


 * WP:NOTFORUM. AndyTheGrump (talk) 23:55, 2 August 2015 (UTC)

Thanks, all. Joseph A. Spadaro (talk) 04:02, 4 August 2015 (UTC)

Knee anatomy
There is a large cord I can see and feel on the lateral (outside) part of the knee and I'm curious what part of the knee it is. Here is a picture http://i58.tinypic.com/2j1sksz.jpg I am thinking either the LCL, the  IT band, or the hamstring.--Tarhound21 (talk) 07:47, 2 August 2015 (UTC)
 * See Knee. That is indeed the fibular collateral ligament - the hamstring is positioned more medially (down the centre of the knee at the back, not at the side). Tevildo (talk) 08:17, 2 August 2015 (UTC)
 * No.
 * From the picture it looks as if the OP has the tip of his index finger on the common (long and short head) tendon of biceps femoris, which is part of the hamstrings. The OP can confirm this by palpating the tendon while attempting to further flex the knee (by contracting the hamstring) while trying to rotate the lower leg (as indicated by the front part of the foot) towards the outside (= external rotation of the lower leg and foot), while the knee remains in the position as photographed. If the knee does not flex or rotate (by keeping the foot firm on the ground and not moving the body or upper leg) only tendons that are attached to muscles would tighten, while a (passive) "tendon only" cross-joint tendon would not alter its tension or orientation.
 * The fibular collateral ligament (FCL) runs between the the lateral epicodyle of the femur and the fibula. The lateral epicondyle would be 4 to 5 cm "anterior" - approximately in the 12 o'clock position - relative to the fingertip on the picture. If one palpates between that bony point and the top of the fibula (where biceps femoris also inserts) one will feel a ridge that is the FCL. In the position illustrated in the picture, the FCL would be orientated vertically down towards the floor.
 * The hamstrings are not "down the centre of the knee at the back", they form the lateral (outside) and medial (inside) borders of the popliteal fossa behind the knee. Christom — Preceding undated comment added 17:20, 2 August 2015 (UTC)

How do mammals that live in seawater avoid dehydration?
So as not to end up as humans would as explained here? 75.75.42.89 (talk) 19:32, 2 August 2015 (UTC)
 * They can excrete excess salt more efficiently than humans. Ruslik_ Zero 19:49, 2 August 2015 (UTC)


 * What you seem to be asking is what do strictly-seagoing mammals use as their water source. Googling the subject ("where do [mammal name here] get their water?" indicates that they ingest seawater to some extent, but that much of their water comes from fish they consume. ←Baseball Bugs What's up, Doc? carrots→ 19:51, 2 August 2015 (UTC)
 * Don't mean to bite, but this seems like an exceedingly easy question to google. The very first result seems to have all the answers. Vespine (talk) 22:59, 2 August 2015 (UTC)


 * They excrete the excess salt. Okay, that's kind of the obvious answer. From the evolutionary perspective, doing so requires actively transporting the ions against the concentration gradient (seawater is saltier than the animal's body), which requires energy. This means less energy available to the animal for other purposes. For animals living in saltwater, this is just an unavoidable cost of maintaining homeostasis. But on land, and in freshwater, the problem is the opposite: it's difficult to get enough salts in your diet. The body has to limit how much is excreted. Since the ability to concentrate and excrete excess salt is no longer necessary, there's a strong selective pressure against it, to free up the resources that would be invested in such a trait. In the case of marine mammals, they evolved from land-dwelling mammal ancestors and then re-adapted to living in a marine environment. There are many signs of this, such as the fact that their flippers and fins are modified arms/hands and legs/feet, complete with little vestigal foot bones in whales. This kind of thing, when species that aren't closely related but live in similar environments develop similar traits, is called convergent evolution. --108.38.204.15 (talk) 02:38, 3 August 2015 (UTC)

Turner syndrome
I have a niece with this condition and one symptom was her large bulbous neck at birth. Yesterday I was talking to a friend and she mentioned her son had this funny (large bulbous?) neck at birth. On reading the article about Turners, is this only females that get this syndrome? Can extra skin around the neck at birth mean anything else? 203.97.202.181 (talk) 21:32, 2 August 2015 (UTC)
 * The article says it's females only, due to a missing X-chromosome. Assuming the article is correct, your friend's son must have some other condition. ←Baseball Bugs What's up, Doc? carrots→ 21:38, 2 August 2015 (UTC)
 * We have an article on "webbed neck" that lists some other causes besides Turner syndrome, but we cannot diagnose what (if anything) is present in a particular person. Wnt (talk) 03:16, 3 August 2015 (UTC)
 * It's absolutely possible for a son to have Turner's syndrome if there is also mosaicism. A karyotype of 46,XY/45,X would result in a child with Turner's syndrome, and, depending on where in the body the 45 X cells are, the child could be either a boy or girl. See .  There is also this review of postnatally diagnosed cases of 45,X/46,XY mosaicism in which 3 males considered normal at birth later developed signs of Turner's syndrome. It's quite rare, and I suspect that our article is oversimplifying in an effort to keep things simple. - Nunh-huh 23:54, 3 August 2015 (UTC)