Science desk
< May 24	<< Apr \| May \| Jun >>	May 26 >

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

May 25

Earth's gravity and humans

If, for example, Earth's gravity was 1/3 less than it was now, which is more likely?

a) Humans would be shorter to become more agile

b) Humans would be larger in size and mass to cope with the weaker gravity

Any help would be appreciated! 174.93.64.185 (talk) 01:29, 25 May 2011 (UTC)[reply]

Both possibilities are speculative at best. Numerous scientific authors have published informed speculation about how intelligent life may develop on Earth-like planets, or on planets with varied conditions. You might check up the works of Carl Sagan, Iosif Shklovsky, and so on. Intelligent Life in the Universe, available for purchase, is one the more well-thought-out analyses that explores how life may adapt and evolve in various conditions. Nimur (talk) 02:45, 25 May 2011 (UTC)[reply]

Science (including biology) should be able to make predictions and extrapolations from existing conditions to other conditions, if it has meaningful theories and principles. Otherwise it is an exercise in labelling and fabulous "Just So Stories" about how things came to be as they are. This is not just "science fiction speculation." What if some exoplanet had 1/3 more or less oxygen in the air? What if there were 1/3 more or less solar radiation? What if the mean temperature were so many degrees higher or lower? What if gravity were 1/3 more or less? If a man weighing 180 pound (or a mass of 81 kg, or 13 stone for those in the "stone" age) had to carry a backpack weighing 1/3 of that amount, climbing stairs would feel much the same as if he were on a planet with 1/3 more gravity. He would still be able to get around, just not as fast or as far. If he were adapted to always carrying the load, and were suddenly freed for it, his mobility would be enhanced. Astronomy is finding more and more planets somewhere near the "Goldilocks" zone where conditions are similar to those of Earth. (Our articles Astrobiology and Habitable zone strangely do not mention gravity as a parameter of animal or plant life). Could plants and animals something like those on Earth survive on some newly discovered exoplanet? Exobiology (or Astrobiology as Wikipedia calls it) should be able to make predictions of habitability, and should be able to predict what adaptations would be necessary. It is an easy experiment to raise small plants and animals in a centrifuge with higher gravity than on Earth, to see what adaptations are found, or to see what Earth plant and animal species can survive high gravity. See "Fundamentals of space biology: research on cells, animals, and plants in space" (2006) by Clément et al., Chapter 3, "Facilities for gravitational biology." It discusses microgravity and centrifuge experiments. In microgravity on the ISS, we could see the effects of virtually no gravity. For 2/3 Earth gravity, in principle a habitat could be created using a centrifuge in Earth orbit on the ISS or other experimental platform. Perhaps mice would thrive and leap high, plants would grow taller and thinner, and cockroaches would thrive (as under most conditions). A reference from Google Book Search discussing gravity and possible life forms: "Life in the solar system and beyond" (2004) By Barrie William Jones, page 233: "In the high gravity of a massive rocky planet squat life forms might be common, or life might be confined to oceans and other bodies of liquid water that provide support. 'Birds' might be unknown. In low gravity we expect soaring structures, perhaps very large, and air thick with flying creatures." Gravity would also affect the ability to retain an atmosphere, with profound consequences for habitability. The original question only has two options, but perhaps it should allow a third option: humans might be taller or of the same height but with less massive skeletons, and able to climb and leap from heights with less fear of injury, like chimpanzees and monkeys. (Edison (talk) 15:17, 25 May 2011 (UTC)[reply]

The Wikipedia article about Human-powered aircraft would need a major rewrite. Cuddlyable3 (talk) 21:18, 25 May 2011 (UTC)[reply]

I think Great Mambo Chicken and the Transhuman Condition: Science Slightly over the Edge would be of interest to you. As I recall (could be wrong), some chickens were put into centrifuges and kept at a constant 3 x gravity environment and became Great. Mambo. Chickens. Of course, that's adaptation, not evolution, and the (chicken) body's mechanisms of adaptation to gravity changes are as untested (and possibly counterproductive) as ours. Wnt (talk) 22:40, 25 May 2011 (UTC)[reply]

Psychoanalysis and Schizophrenia

I've been reading, Freud and the Far East, which seems to support the notion that psychoanalysis has and is being used in the present day as a method for treating schizophrenia. I'm wondering if this claim has any validity considering most perspectives would assert that it would be ineffective and that medication would be the only option available. 174.22.60.247 (talk) 03:03, 25 May 2011 (UTC)[reply]

Schizophrenia#Management suggests there are possible non-medication treatments for schizophrenia available at the moment, although their effectiveness is generally questioned. I therefore would imagine that psychoanalysis being used is not inconceivable, although I know little about the subject. Grandiose (me, talk, contribs) 09:29, 25 May 2011 (UTC)[reply]

Freud, if I remember correctly, did not himself find psychoanalysis to be all that effective for schizophrenia. There were, however, a number of later psychoanalysts who were more optimistic. In any case, the popularity of psychoanalysis for any condition has dropped off radically in recent years -- the majority of psychologists consider it to be a discredited approach. Note, though, that there are numerous non-drug-based treatment approaches that have no particular relationship with psychoanalysis. Looie496 (talk) 18:01, 25 May 2011 (UTC)[reply]

Freudian psychoanalysis is pretty much gone, but psychodynamic therapies based on more recent understandings of Freud and object-relations theory are one of the only effective therapies for personality disorders and other severe dissociative disorders, such as DID. This is not well-known among therapists who do not work primarily with this clientele. I can't see this working for schizophrenia, however.

Obviously it is possible to use "talking therapies" and drugs (medication) at the same time. That is increasingly recommended for depression, I don't know about schizophrenia and it is wise to assume that practice varies widely from one country to another. Itsmejudith (talk) 10:24, 26 May 2011 (UTC)[reply]

Dual-brain theory & ambidexterity

Non-superimposable actions, or 'mirror-image' works are easier when we use both hands simultaneously. Also same actions using both hands are easier but not different actions. Example, why is that difficult to write different words using both hands simultaneously? Though there are two autonomous minds according to dual-brain theory that states one hemisphere dominates the other, I want my net action to be two different words written using both hands at the same time. Is that like, my mind prefers left hand or right hand's action or is there another mind (the one I intend to use for my required action) that helps me out? Put in other words, when I think, it is my mind that is used to do a challenging action. In that case where does dominance come in? Does that not help me do what i want? hope it is not confusing - anandh, chennai — Preceding unsigned comment added by 199.224.149.10 (talk) 11:58, 25 May 2011 (UTC)[reply]

Wikipedia has articles on Ambidexterity and Lateralization of brain function that tackle these subjects. Cuddlyable3 (talk) 21:12, 25 May 2011 (UTC)[reply]

Also split-brain and agenesis of the corpus callosum are fascinating.. Vespine (talk) 22:44, 25 May 2011 (UTC)[reply]

I have 3 questions about the :Narwhal?

I have 2 questions about the :Narwhal: 1. Have there been or are there any Narwhals in zoos? 2. Can anyone name any documentaries specially about the Narwhal? 3. Where is the best place to go Whale watching for Narwhals? Thanks! [User:Neptunekh2|Neptunekh2]] (talk) 12:20, 25 May 2011 (UTC)[reply]

This link has some interesting information about the Canadian restriction on hunting being confined to the Inuit people. It seems the Inuit are not keen to alow narwhals to be kept in zoos. Greenland may have different ideas, but I doubt it. Richard Avery (talk) 13:14, 25 May 2011 (UTC)[reply]

This company offers an "Arctic Narwhal Adventure" on Baffin Island. Alansplodge (talk) 17:50, 25 May 2011 (UTC)[reply]

The narwhal article does say that narwhals "tend to die" in captivity, supported by this NY Times copy and paste, though the NY Times article itself doesn't in turn provide an atom of data beyond the phrase "tend to die". This writeup from a "captive-whale advocate" organization in Canada says, "No dolphinarium has ever been able to keep narwhal whales alive in captivity, and the Vancouver Aquarium killed 7 narwhals trying" in 1968-70; the six narwhals that survived to make it into the aquarium itself all died from "bacterial infections and starvation". This site, the "Narwhals Association of America" echoes this, saying that all narwhals brought into captivity have died within a few months. Comet Tuttle (talk) 18:03, 25 May 2011 (UTC)[reply]

It sounds like the article is soft-peddling it. If the cause of death is "bacterial infections and starvation", then it would be more accurate to say that "human captors tend to kill them" (through negligence) rather than "they tend to die" (as if it were the narwhals' fault somehow). ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:46, 26 May 2011 (UTC)[reply]

That was 3 questions! Re Q2 Episode 1 "The Great Melt" of the BBC's 2009 nature documentary series Nature's Great Events included footage and descriptions of narwhal. The series is commercially available as described in the article. {The poster formerly known as 87.81.230.195} 90.201.110.194 (talk) 19:22, 25 May 2011 (UTC)[reply]

Carbonmonixide`s reaction with water

How does Carbonmonoxide (CO;gas) reacts with with water (H20;liquid)? — Preceding unsigned comment added by 41.19.122.40 (talk) 13:17, 25 May 2011 (UTC)[reply]

I think that carbon monoxide should be quite stable in solution, but if it does react the first point of attack should be the carbon atom. This should form a formyl and a hydroxyl radical, this in turn, reacts to form a formic acid molecule. According to classical thinking, carbonous acid is known as carbonous hydrate or hydrate of carbon monoxide, but this not formed as carbonous acid is highly unstable in solution. It is even known that carbonous acid is a protomer of formic acid in the gas phase. Plasmic Physics (talk) 14:00, 25 May 2011 (UTC)[reply]

At high temperatures (usually in the vapor phase) or under catalysis, CO and H₂O can undergo the water gas shift reaction. -- 174.31.219.218 (talk) 15:48, 25 May 2011 (UTC)[reply]

Size of carbonate and nitrate ion

Hello,

As part of a science project, I need to compare the sizes of the carbonate CO₃^2- and nitrate NO₃^- ions. However, I can't seem to find them... I would be very grateful if somebody knows where I can find this data and lets me known!

Thanks a lot,

Chtit draco (talk) 14:48, 25 May 2011 (UTC)[reply]

What do you mean by size? A distance between two points, a volume, or maybe a ratio of some kind? Plasmic Physics (talk) 00:02, 26 May 2011 (UTC)[reply]

More like a volume. What I'd like to know is which one "take the most place" in a given environment. Chtit draco (talk) 08:01, 26 May 2011 (UTC)[reply]

What I can tell you, is that you want to find the van der Waals volume. This depends on three things, the van der Waals radii of the constituent atoms and the bond lengths, and bond angles.

N.B. molecular's do not have a real volume, as a real surface is requisite for a real volume. Thus, there are numerous types of pseudovolumes, of which the above described type is one. Plasmic Physics (talk) 08:13, 26 May 2011 (UTC)[reply]

I don't have experimental evidence, but only computational chemistry values of 42.84 Å³ for carbonate and 39.54 Å³ for nitrate. Plasmic Physics (talk) 08:18, 26 May 2011 (UTC)[reply]

Probably the key measurement is the C–O and N–O bond-lengths (I'm surprised our article does not have this parameter for either ion, cf. sulfate for example). Each ion has the same trigonal–planar geometry with each peripheral atom an oxygen, so a main consideration is how far out those oxygen atoms are. The VDW radius of the oxygen (approximate extent of its valence electron cloud) probably varies a small amount due to different anionic character between the two structures. Each structure is probably about as "thick" as the diameter of the thickest atom, so can approximate it as the VDW diameter of the C or N. DMacks (talk) 19:48, 26 May 2011 (UTC)[reply]

I calculated the following distances and volumes:

Level of theory	CO separation / Å	NO separation / Å	CO₃²⁻ volume / Å³	NO₃⁻ volume / Å³
PM3	1.293	1.239	45.53	40.24
HF 6–311+G**	1.282	1.222	45.30	39.92
B3LYP 6–311+G**	1.308	1.260	45.85	40.65
MP2 6–311+G**	1.310	1.262	45.90	40.68

In crystal structures, the CO distance in carbonates is usually about 1.27-1.29 Å. The NO distance in nitrates is usually about 1.22–1.27 Å.

Ben (talk) 15:13, 28 May 2011 (UTC)[reply]

Wow thanks a lot! Chtit draco (talk) 11:46, 2 June 2011 (UTC)[reply]

Non-cassein cheese

I know that you can remove cassein and I believe lactose from milk but could you make cheese from that milk if the casein is removed? Is that at all possible? — Preceding unsigned comment added by 71.137.245.160 (talk) 15:01, 25 May 2011 (UTC)[reply]

Cheese is normally produced by coagulation of casein (see Casein#Cheesemaking), so it's hard to see how cheese could be made out of casein-free cow's milk, and Google doesn't immediately turn up anything like that. However, if the reason you're asking is because you're wanting to avoid casein due to a milk allergy or something, one solution would be a vegan cheese analogue. Red Act (talk) 15:44, 25 May 2011 (UTC)[reply]

Red blood cells and erythropoietin in early stage renal artery stenosis

I'm trying to get my head around renal artery stenosis and its effect on blood count. I appreciate that in later stages of the disease, a chronic renal failure type picture predominates, and hence reduced erythropoietin production leads to anaemia.

However, would the early stages of this disease be characterised by an increased red blood cell count and higher levels of produced erythropoeitin?

My proposed mechanism: Mild stenosis -> reduced renal blood flow -> mild renal hypoxia -> increased erythropoietin production

I don't seem to be able to find anything about this anywhere, so if anyone has any thoughts I'd appreciate your two-cents. — Preceding unsigned comment added by 130.88.0.82 (talk) 15:39, 25 May 2011 (UTC)[reply]

The electron is not perfectly round?

I thought it was a point-like particle. [1] 66.108.223.179 (talk) 21:56, 25 May 2011 (UTC)[reply]

Its dipole moment is not exactly zero, but then they were not able to detect it. Count Iblis (talk) 22:33, 25 May 2011 (UTC)[reply]

See Electron electric dipole moment, Ref. 3 is the article the BBC has reported on. Count Iblis (talk) 22:37, 25 May 2011 (UTC)[reply]

So which is hyperbole: When people say that the electron really is a point particle, or when the article says it has a shape. Both can't be true. I've heard very serious physicists say that it really is a point particle, but does that just mean it is smaller than anything we could measure? 169.234.143.14 (talk) 03:37, 26 May 2011 (UTC)[reply]

"Both can't be true". Perhaps neither is? 'Points' and 'shapes' are concepts we use to describe the universe at the scale we see it. They may not be 'real' at all. AndyTheGrump (talk) 03:56, 26 May 2011 (UTC)[reply]

In explanation a few minutes ago on BBC Radio 4, the team leader from Imperial College, London, explained that the "size" of the electron is the result of the "cloud of fluff" surrounding the electron, made up of elementary particles flickering in and out of existence for very short times. The roundness has been measured to amazing accuracy. The analogy he suggested was that if the electron was enlarged to the size of the solar system, then any irregularity must be smaller than the thickness of a human hair. He claimed that ten times this accuracy would be achievable soon, possibly ruling out many alternatives to the Standard model. Dbfirs 16:16, 26 May 2011 (UTC)[reply]

"Point particle" simply means that the model of the electron is zero-dimensional, and only needs its x,y,z coordinates to completely define its position. For almost all models of the electron, we assume its mass is exactly constant; its charge is exactly constant; and because electron is an elementary particle, those two parameters are essentially fundamental constants of the universe. We get very far in atomic theory, high energy physics, and quantum electrodynamics, using this simple model. The recent paper is basically suggesting that in some (fairly contrived) experimental setup, this model is insufficient. I think it would be more straightforward if they said "the electron has a preferred direction, under certain high-energy circumstances," or that "an interaction with an electron has been discovered that is not spherically symmetric," rather than that "the electron is not round." Electrons never were round; they do not have a "surface" that we could describe geometrically. Electron interactions are described quantum-mechanically, usually using Coulomb's law for most purposes (including most applications in quantum mechanics); as you know, Coulomb's law is entirely isotropic. At higher energy, physicists must describe electron interactions by characterizing the properties of mediating particles (such as the photon); these descriptions are statistical, but are also isotropic on the average (so, we can loosely say the interaction is spherically symmetric). In no case have I ever seen a physics treatment that solved for an electron interaction by describing the "shape" of the particle. Nimur (talk) 16:33, 26 May 2011 (UTC)[reply]

I just want to point out that electric dipole (That's what this experiment is trying to measure) is NOT incompatible with the idea that the electron is a point particle. Dauto (talk) 00:50, 27 May 2011 (UTC)[reply]

Could I be allergic to something in the milk, and not the milk itself?

So, I stopped drinking milk, because it gave me mild allergic reactions- itchy eyes, itchy throat- that felt not unlike hay fever. Nothing fatal, just mildly unpleasant. That was back when I bought my skim milk at the grocery store. But then I went back to drinking milk, because it stopped giving me that reaction- I thought I'd outgrown the allergy or something. Today, I had some skim milk from the grocery and had the same reaction, and suddenly realized that the milk I've been drinking, the milk that doesn't make my throat feel swollen, is whole, non-homogenized milk from the farm. The solution is obvious, of course- I'm going to go back to getting my milk from the farm. But I'm curious- is there something other than milk in the grocery milk that a person could be allergic to? -FisherQueen (talk · contribs) 23:09, 25 May 2011 (UTC)[reply]

My first guess would be that the grocery-store cows are eating something that the farm cows aren't, and that's making its way into the milk and giving you an allergic reaction. --Carnildo (talk) 01:03, 26 May 2011 (UTC)[reply]

Have you tried any other milk other then skim milk? I don't think pasteurizing could be the source of the issue. Have you tried rBST free milk? Vespine (talk) 01:38, 26 May 2011 (UTC)[reply]

According to Lactose intolerance#Dairy products, "low fat dairy foods ... often have various dairy derivatives such as milk solids added to them to enhance sweetness", which could make it harder to handle skim milk if your milk allergy or lactose intolerance or whatever is caused by something that's more concentrated in the milk solids. Red Act (talk) 02:39, 26 May 2011 (UTC)[reply]

Solar rotation. Why exactly does the sun's equatorial region rotate faster?

Hi, the Solar_rotation page says how much the equatorial rotation of the sun is faster. It doesn't say why though. The centripetal force caused by the sun's rotation is bigger at the equatorial region. Maybe that causes the material at that latitude to rotate faster around the core? Or maybe the the magnetic lines emanating through the core cause the polar regions to rotate slower? Some kind of force must be responsible for the differential rotational speed between the polar and equatorial regions... TIA --InverseSubstance (talk) 23:13, 25 May 2011 (UTC)[reply]

According to Differential rotation#The cause of differential rotation, convection moves mass around, along with its angular momentum. Clarityfiend (talk) 04:31, 26 May 2011 (UTC)[reply]

Isn't it rotating faster because it's farther out from the center, similar to how each successive link of the chain of a ball and chain is traveling at a higher velocity until you get to the ball itself, which is traveling the fastest? DRosenbach ^{(Talk | Contribs)} 15:41, 26 May 2011 (UTC)[reply]

No, the angular velocity is faster at the equator, not just the linear velocity. In contrast, if you're swinging a ball and chain, the angular velocity would be the same for the whole ball and chain. Red Act (talk) 15:58, 26 May 2011 (UTC)[reply]

The chain link closest to your hand orbits on the path of a circle the radius of 1 inch while the 10th chain link orbits on a path of a circle the radius of 10 inches, but they both do so in the same time of X seconds -- so it must be that the 10th chain link is going faster in traveling the 10π circumference while the first chain link is only traveling the 1π circumference. DRosenbach ^{(Talk | Contribs)} 05:38, 27 May 2011 (UTC)[reply]

If the ball and chain makes a complete circle in X seconds, then a link at radius 1 travels a distance of 2π (the circumference of a circle is 2πr) in X seconds, and a link at radius 10 travels a distance of 20π in X seconds. But the magnitude of the angular velocity, i.e. the angular speed, is 2π/X radians/second for both links. In contrast, not all parts of the sun move the same number of radians per second. Red Act (talk) 06:03, 27 May 2011 (UTC)[reply]

We're talking about the angular rotation speed here. You'd expect the angular rotation speed to be the same over the whole sphere if the sphere were a solid body. In the sun the angular rotation speed increases as the latitude approaches the equatorial regions. I can't understand how convection of hot mass from the core of the sun moving outwards would increase the angular rotation speed at the equatorial regions. Where does the push come from that makes the plasma rotate faster? Having cooler mass from the surface fall towards the center also doesn't seem to provide any push. There has to be some reason for why the mass at the equatorial regions rotates faster than the poles. This is curious because the differential rotational speed between the poles and the equator is what causes the magnetic field lines to wrap up around the sun. (see video)http://www.youtube.com/watch?v=-PTQaOWkEfs&feature=related That takes energy. Those magnetic field lines take energy to distort. Where does that energy come from? As the magnetic field lines get wrapped up, they tangle and bunch, and ultimately cause sunspots. When the tangled magnetic lines realign a lot of energy is released sometimes causing bursts in charged solar wind particles. --InverseSubstance (talk) 16:05, 26 May 2011 (UTC)[reply]

I'd have been very surprised if a non-solid body did rotate at the same angular velocity, but as for why, "the physical mechanism ... is still a topic of research." Clarityfiend (talk) 19:35, 26 May 2011 (UTC)[reply]

You may enjoy this website from the Planetary Sciences department at University of California at Santa Cruz: Computer Simulation Studies of Convection, Gravity Waves, Differential Rotation and Magnetic Field Generation in the Deep Interiors of the Sun and Giant Planets. There are some excellent pictures of computer-models of the convection patterns that can cause banding and differential rotation. Differential rotation is observed in most large gas bodies, including our sun and our gas giant planets. Nimur (talk) 02:37, 27 May 2011 (UTC)[reply]