Wikipedia:Reference desk/Archives/Science/2018 July 17

Science desk
< July 16	<< Jun | July | Aug >>	July 18 >

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

July 17

Impairment of dolphin function during sleep

I've heard that dolphins sleep one hemisphere of their brain at a time. Since the hemispheres of the human brain perform different complementary tasks (like, I think, the left side senses or controls the right side of the body/eye while the right side senses or controls for the other side); does that mean that one side of a dolphin's body is impaired during sleep? --129.215.47.59 (talk) 10:43, 17 July 2018 (UTC)

Your assumption that "the left side senses or controls the right side of the body/eye while the right side senses or controls for the other side" is incorrect. See Hemispherectomy and Ahad Israfil. Also see [1]. "The important functions our brain carries out are not farmed out to single distinct brain regions, but instead supported by multiple regions, often in similar but slightly different ways. If one structure breaks down, the others can pick up the slack."[2]

Jeeeee-zus. Peri-insular hemispherectomy has been developed to allow for seizure relief with minimal brain tissue removal. In this procedure, the surgeon aims to disconnect (rather than remove) the hemisphere, in order to minimize long term complications. What if you wake up from the operation to realize that you're the disconnected hemisphere? Wnt (talk) 20:00, 17 July 2018 (UTC)

Split brain patients, although they experience very interesting phenomena, appear to not experience "two consciousnesses". My guess is because they are still connected through the brainstem, particularly the reticular formation, which is central to consciousness. --47.146.63.87 (talk) 07:09, 18 July 2018 (UTC)

I had a look at that paper used to support there being a single consciousness and I believe the conclusion is junk. The findings they got are interesting but they have no relation to anything about consciousness. In fact it would help if they actually gave some criterion for consciousness being detected as being the same - but the results can all be explained by blindsight which people do not associate with consciousness at all - quite the reverse. Dmcq (talk) 12:30, 18 July 2018 (UTC)

Article about the general idea: lateralization of brain function. --47.146.63.87 (talk) 07:09, 18 July 2018 (UTC)

As for dolphins, see Dolphin#Sleeping. Also see [3][4][5] BTW, we (sort of) do it too.[6] --Guy Macon (talk) 16:03, 17 July 2018 (UTC)

While humans and other animals are forced periodically to stop all activity and sleep, dolphins have evolved alternate half-brain sleep as a means of keeping alert against predators (sharks) for more than two weeks. An experiment found that dolphins' echolocation sense was undiminished. In the future a dolphin may be fitted with a portable EEG backpack to learn more about its handling of complex tasks during the half-sleep state. Another experiment found that acquired information is transferred between the two hemispheres of the their brain. DroneB (talk) —Preceding undated comment added 16:17, 17 July 2018 (UTC)

Nutrition: How long does it take to add 10 kg (22 lb) to one's weight, while consuming 5000 kcal per day (by eating cakes)?

Current weight: 50 kg (110 lb).

Current height: 170 cm (5ft7in).

Health: good.

Sports: no. HOTmag (talk) 14:06, 17 July 2018 (UTC)

[7]. --Jayron32 15:06, 17 July 2018 (UTC)

Thnx.

Resolved

HOTmag (talk) 18:26, 17 July 2018 (UTC)

Drowning spiders

Do spiders have any in-built resistance to water? How long does a spider take to drown? I mean ordinary small household ones, not huge furry ones like a tarantula. Thanks. 86.190.109.151 (talk) 18:20, 17 July 2018 (UTC)

Not by any means a full answer to the question, but see diving bell spider. Looie496 (talk) 18:59, 17 July 2018 (UTC)

It depends on the species, but remember temperature is crucial, since arthropods are ectothermic. I've been amazed how long insects can survive submerged in ice-cold water - literally hours! Wnt (talk) 19:57, 17 July 2018 (UTC)

Here's an interesting article about spiders in lab conditions seemingly drowning and then reviving.[8] ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:39, 17 July 2018 (UTC)

In my part of Australia the best known habitat for Daddy Longlegs spiders is the shower cubicle. (The first photo in that article is a perfect example of these cute little guys.) They seem capable of surviving all sorts of inundations. HiLo48 (talk) 23:31, 17 July 2018 (UTC)

Here is our article on this subject.John Z (talk) 04:28, 18 July 2018 (UTC)

With all due respect, the article assumes permanent immunity to rainwater events, provided there is a subsequent solar event each time that is sufficient to dry up "all the rain". Partial drying up of the rain might well reduce resistance and/or impair climbing ability. I'd suggest that some scientific, double-blind testing should be reported, preferably from a peer-reviewed tertiary source. And does this effect hold true only for itsy bitsy size, or does it also extend to bigger lactose-tolerant individuals?? I think we should be told. Martinevans123 (talk) 14:49, 18 July 2018 (UTC)

As chance would have it, I have been conducting informal, admittedly somewhat impressionistic tests of the reported tendency of arachnids to rescale climbs after being subjected to a hydrodynamically consistent deluge of water. Which is to say that, despite being, for the moment anyway, halfway across the world from Hilo, I too have been sharing my shower cubicle with a truly teeny Pholcidae, who has shown the utmost patience and tenacity in responding to my destructive showering habits and the attendant risks to life and web (I'd say life and limb, but she's lost one leg somewhere already, so clearly she's willing to suffer some loses in this regard; I call her "Lucky/#7" and no, shut up, that's not at all weird and no I haven't been accused of talking to bugs too much since I was a kid...).

Of course, all of that has more to do with spider mobility, endurance, and stimuli-response strategies than the OP's original inquiry as to drowning, so--just to prove what a hopeless stick in the mud I am--I'll now follow up my rare attempt here to get in on the humour with discussion of some of the spider physiology that is relevant to that inquiry. Specifically, all spiders who are ambush predators, rather than active hunters (which is to say, the significant majority of all spider species) have evolved a metabolic physiology that is consistent with this ecological niche. Most such spiders cannot be certain of how often their meals will arrive, so while waiting, they enter into states of subdued metabolic function. A happy side-effect of this, from the spider's perspective anyway, is that this aspect of their physiology (while generally believed to be a consequence of their adaption to their particular variation of a predatory ecological niche and the need to conserve calories over an extended period) means that they are also capable of making do on relatively little oxygen for stretches that would kill most other organisms at their level of complexity. This is of course true for a great many arthropods who specialize in long periods of stillness punctuated by rapid bursts of movement in response to certain stimuli. Snow ^{let's rap} 14:26, 20 July 2018 (UTC)

Ah ok. So, in simplistic terns..... "you can't drown 'em if they're hungry"?? Martinevans123 (talk) 14:31, 20 July 2018 (UTC)

It's more that, because they are so adapted to going without their meals for a bit, and accomplish this by staying very still for prolonged periods of time (thus using less of their metabolic reserves) they are also adapted, by consequence, to getting by on relatively little oxygen (relative to closely related organisms that do not play the waiting game, that is). Afterall, the primary need that respiration comes to serve is to catalyze intracellular metabolic functions through oxidization. So, being adapted to periods of prolonged stillness in order to conserve energy between infrequent prey (and for other benefits regarding both predation and their own safety) = being adapted to periods of subdued metabolic function = being adapted to periods of not needing as much oxygen as they otherwise would. But an individual's hunger level at any given time will have insubstantial effect on how long it can go without oxygen; the two functions are just incidentally linked. Snow ^{let's rap} 01:21, 21 July 2018 (UTC)

Ownership of Ryugu and Ceres

Now that we've found this great big pile of fertilizer, we have to decide who is a thief for using it.

The recent mission to 162173 Ryugu seems like the sort of thing that might trigger the thing Obama signed in 2015 (see commercialization of space) creating a new sort of pseudo-property "right" for those who first exploit an outer space object. As a hazardous near earth object, I imagine returning metals from that site should be especially feasible. Also, the Dawn (spacecraft) mission also seems to have done much to scout out resources on Ceres (dwarf planet) - what struck my eye is that the white salt mountains [9] are apparently made of sodium carbonate and ammonium chloride, making Ceres a great place to send nitrogen into space cheap. Now, traditionally, there was not going to be ownership of such things (Outer Space Treaty), and I still don't know how this is going. Should we have a Japanese flag icon on the Ryugu article/infobox? Is it still debated whether one party can claim entire asteroids or minor planets? And to what degree should these scientific missions be taken as prospecting expeditions rather than pure science? Wnt (talk) 20:10, 17 July 2018 (UTC)

This 2010 episode of Big Picture Science - the official podcast of the SETI Institute - is entitled Space Race 2.0. Among the esteemed guests were Burt Rutan and a few others; the topics discussed included property rights law in the new era of spaceflight.

In my storied days of hanging around with space-weirdos, I've met a fair shake of characters who are very enthusiastic about property rights (and mining rights) for objects in outer space. I've met a few who tried to sell these property rights to the U.S. government, the duke of Luxembourg, and the billionaires who run Silicon Valley. It is my estimation that most of these fine entrepreneurial-spirited characters are comprised of that most fascinating dual combination: crank-scientist and con-artist. It doesn't mean that they don't get high-profile press coverage - just that they aren't really people who you ought to take seriously.

Regarding the topic: the reliable sources for our articles ought to be official statements by governments, space agencies, and if we're being generous, we could accept official press releases from commercial spaceflight entrepreneurs who have at least actually launched a real mission. (As of 2018, there are a lot fewer of those commercial spaceflight entrepreneurs than the mass-media would lead you to believe).

JAXA's website on the Hayabusa 2 space probe does not make any public assertion of any property ownership right. Real spaceflight engineers tend to be a realistic bunch who try to avoid making ridiculous statements. On the other hand, the folks who associate with the so-called "NewSpace" movement - the kind of space-groupies who talk about near-term space-colonialism and mineral ownership contracts - tend to be proponents of, or at least victims of, pseudoscience, counterfactuals, and general quackery.

Nimur (talk) 20:25, 17 July 2018 (UTC)

Space law, Outer Space Treaty, Commercial use of space, Treaty Clause. --Guy Macon (talk) 22:24, 17 July 2018 (UTC)

Under what legal or philosophical principle do these individuals claim to have property rights over space stuff that they could sell to the US Government or anyone else? Iapetus (talk) 10:10, 18 July 2018 (UTC)

If I could generalize, I would say that many enthusiasts embrace an analogy between extraterrestrial territory and the open range of the American West; they espouse a few bold and provocative ideas about "manifest destiny in space" that sound exciting and adventurous; they put together business-proposals by cherry-picking scientific data-points from reputable space-research; they can make the profit potential sound really incredible; and all this hubris lasts until anyone inquires about how heavy the life-support systems will need to be in the space-rancherias, or how we'll actually build them - right about when the project is mature enough to require an actual scientist or engineer. Then it collapses, everyone has a good laugh, and the investors eat the losses - or better yet, they sell it to a government who doesn't know any better. ...or they sell it to one whose ulterior motive is undisclosed but for its unspokenly obvious infatuation with commercially acquiring very large rockets.

The whole lifestyle is developed when the reader of science fiction takes certain fictions a little too seriously. It's hard to say when the "space cowboy" genre was invented, but we can surely call out a few key works: in the 1966 fictional work, The Moon Is a Harsh Mistress, Robert Heinlein lays out a political philosophy of libertarian idealism and the economic and political implications of moon-colonialism. I have actually heard this book cited in a sales pitch for an asteroid mining venture. In multiple distinct instances.

While such fiction can be entertaining and inspirational, it ought not be used as an actual model for real life: the book's details are fiction. Also, ... in that story, everybody dies, the space-government collapses, and the colonists get stranded on the moon, so even if we suspend our disbelief of the scientific details, it's a story about a failed space mining venture. It just goes to show that certain attention-deficient individuals can't even get to the last chapter of the fiction-book they idolize.

Nimur (talk) 14:15, 18 July 2018 (UTC)

I think you need to re-read The Moon Is a Harsh Mistress, as your description of the story is highly flawed. The moon in that novel has several viable colonial cities with many "colonists" being transportees (think colonial Australia). The lunar colonists revolt against terrestrial control and win their independence. A few major characters die, but several others do not. --Khajidha (talk) 23:18, 24 July 2018 (UTC)

@Nimur, Wardog, and Wnt: I happened to see this [10] on my local paper's website today and thought it may be of interest. Although the title may suggest it only concerns the moon rather than any asteroid, it actually does discuss them. It's from The Conversation (website) so probably of better quality than the normal crap you get in the papers and is written by this professor [11] [12]. Nil Einne (talk) 15:15, 25 July 2018 (UTC)