Wikipedia:Reference desk/Archives/Science/2013 April 5

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April 5

Stars that becomes a white dwarf

Since our article said Although white dwarfs are known with estimated masses as low as 0.17 and as high as 1.33 solar masses, the mass distribution is strongly peaked at 0.6 solar mass, and the majority lie between 0.5 to 0.7 solar mass do we know exactly how much our sun will lose mass by the time it reaches white dwarf. I scientist already knew exactly how much mass will sun lost by the time it gets to white dwarf. I didn't think the 3 solar mass stars will become white dwarf, I remember in my astronomy class I took, it was star between 0.7 to 1.4 solar mass stars becomes white dwarf. But White dwarf article said 8 solar mass stars become white dwarf.--69.226.42.134 (talk) 00:12, 5 April 2013 (UTC)

When a star becomes a white dwarf doesn't just depend on how massive it is, it also depends on what it is composed of and how massive it is once it has fused most of its hydrogen and helium. The white dwarf article explains that a star of 8 solar masses is massive enough to fuse oxygen and helium into carbon, but not massive enough to fuse carbon. So once that process is finished, that's when it becomes a white dwarf. As for the fate of our sun, see Sun#After_core_hydrogen_exhaustion. 203.110.235.3 (talk) 05:06, 5 April 2013 (UTC)

See also Formation_and_evolution_of_the_Solar_System#The_Sun_and_planetary_environments. Ruslik_Zero 19:29, 5 April 2013 (UTC)

Hydrogen spectrum picture in hydrogen article

Is this picture showing four different spectral frequencies that hydrogen emits on? (It is only visible in the enlarged picture.)My understanding is that there would be two places in the spectrum to find hydrogen. A positive and negatively charged frequency. If that is wrong, or if I am misinterpreting what the vertical lines indicate a clarification would help me greatly. I am working on isolating and transmitting hydrogen from the spectrum.64.91.201.2 (talk) 01:02, 5 April 2013 (UTC)

There are 5 lines, not 4, all of which are from the Balmer series. "Positive and negative charged frequency" is meaningless. "Isolating and transmitting hydrogen from the spectrum" has no discernible meaning. --140.180.248.141 (talk) 03:15, 5 April 2013 (UTC)

The Balmer series is those hydrogen lines that appear in the visible spectrum, but the entire spectrum of hydrogen can be derived from first principles by the Rydberg formula; that formula was an important keystone in building modern atomic theory as it provided the mathematical underpinning of the Bohr model; it is vital to note that Rydberg arrived at his formula quite independently of Bohr, or indeed any quantum theory at all, as the formula predates the Bohr model by 25 years. Rydberg's formula was merely a descriptor of the lines in the hydrogen spectrum, but Bohr used it as the key piece of evidence in his quantum absorption-transmission model of electron behavior. The "n" values in Rydberg's formula were later shown to be functionally identical to the principal quantum number as understood by modern quantum theory. --Jayron32 04:40, 5 April 2013 (UTC)

SPACE TRAUMA

Please check whether fact no. 6 of this linked article under the heading "Space Trauma" is right or wrong. Britannica User (talk) 06:12, 5 April 2013 (UTC)

It's Right. People will not explode in space.

See Space exposure

and Effect_of_spaceflight_on_the_human_body#Direct_exposure_to_the_extreme_environment_of_space

Basically stepping outside a spaceship would cause a lot of problems for you, but the first thing to become fatal would be simple suffocation. You'd lose consciousness after about 10 seconds and be completely dead after about 90 seconds. (Why so much faster than drowning? It's impossible to hold your breath in space. The pressure difference is too great.) APL (talk) 06:23, 5 April 2013 (UTC)

yeah. if your skin would explode from 1 atmosphere pressure differential, you could presumably do major local damage to yourself with the nozzle of a good vacuum cleaner. doesn't happen. For something like liposuction, for instance, it requires a major amount of physical digging to loosen the tissue, the vacuum itself won't rip it loose. Gzuckier (talk) 20:13, 5 April 2013 (UTC)

Also of interest; Rapid_decompression#Exposure_to_a_vacuum_causes_the_body_to_explode. 203.27.72.5 (talk) 05:50, 8 April 2013 (UTC)

Important Questions (about brains and magnets)

1. It is a common phenomenon that a bar magnet, when suspended from a string, align along the south to north direction. Is there any lurid description of this phenomenon? Why don't it align in east to west direction?
2. Why do two magnets attract(or repel) each other?
3. Is it true that every multicellular organism has a brain? If not, then how they function. And is there any multicellular organism having more than one brain? I have heard that a snail has 32 brains; is it true? Scientist456 (talk) 07:21, 5 April 2013 (UTC)

I added to your title to make it useful. StuRat (talk) 07:46, 5 April 2013 (UTC)

1) I'm guessing you want a lucid description, not a lurid one, although a lurid one might be more fun: "The magnetic line of force approaches the magnet silently from behind, and flings it recklessly about, until the final act, when it pins it mercilessly in one spot, never relenting.".

2) Physics isn't very good at explaining why basic forces of nature behave as they do, it simply observes that they do, and comes up with formulas to describe how they behave. The basic observation for magnets is that opposites attract and likes repel (so only the middle pair in the drawing below attract). We can put that into a formula, but that still doesn't explain why.

+--------+   +--------+   +--------+   +--------+
| +    - | R | -    + | A | -    + | R | +    - | 
+--------+   +--------+   +--------+   +--------+

3) This will depend on how you define "brain". The most basic definition might be a nerve cluster, in which case humans have multiple brains, too. StuRat (talk) 07:54, 5 April 2013 (UTC)

Mesozoans, Placozoans and Sponges are multicellular animals that have no nervous system at all. --Guy Macon (talk) 08:24, 5 April 2013 (UTC)

The most common (extremely common too!) multicellular organism without a brain is the entire plant family. Wickwack 121.221.88.3 (talk) 10:38, 5 April 2013 (UTC)

Not the entire plant family (more accurately plant kingdom). See green algae. Although I do believe that all embryophytes (commonly called"land plants") are multicellular. Equisetum (talk | contributions) 12:46, 5 April 2013 (UTC)

there is a school of thought that considers a bunch of "unicellular" organisms floating around to be a multicellular organism, just one where the cells aren't affixed to each other. even when the cells involved are of multiple species, genera, kingdoms, etc. Gzuckier (talk) 20:18, 5 April 2013 (UTC)

1) The reason that a magnet (and a magnetic compass) aligns North-South instead of East-West is that the Earth itself behaves like a bar magnet, aligned approximately through the North and South Poles. The cause is ultimately the rotation of the Earth, through currents in the outer core, probably caused by interaction between lodestone (or more marginally magnetised magnetite or pyrrhotite), convection currents and the Coriolis effect (there are various theories). What we call the north pole of a magnet is more correctly called the "north-seeking" pole (because it is attracted by the "south-seeking" pole of the Earth near to the North Pole. (Yes, I know that's confusing, but just remember that the pole of a magnet that points north is called the north pole, whilst the North pole is a geographical concept.) You might be interested in the article on Earth's magnetic field. Dbfirs 11:39, 5 April 2013 (UTC)

Trees are multicellular, and have no brain. To expand on StuRat's decent answer, a cluster of nerves cell bodies is called a ganglion; your brain is basically a giant, specialized ganglion (more properly, the core of the brain is the basal ganglion, where as the brain is sort of organized around that). Most animals have brains of some sort, but there are some animals where the "brain" (that is, the ganglion in the head) is not significantly larger than other ganglia in other parts of the animal, in these cases you sometimes here the idea that the animal has multiple "brains", but properly the brain is the ganglia in the head. As I noted in the first sentence, plants have no nerves and no brains, but are multicellular. In the animal kingdom, Cnidaria (primitive sea creatures including jellyfish, sea anemones and coral) have no brains at all, neither do other related phylla of sea creatures like Ctenophora and the Sponges.--Jayron32 12:23, 5 April 2013 (UTC)

2) I am not sure if anyone knows 'why' things attract or repel each other (magnets, charges, bodies etc). I guess it has something to do with Fundamental_forces - WikiCheng | Talk 12:27, 5 April 2013 (UTC)

It depends on the meaning of "why". "Why" can mean "by what mechanism does it work". We know that answer. Magnets attract because of the attractive nature of the electromagnetic force, and is best modeled as the behavior of a magnet within a Magnetic field. Field theory is not simple to understand, but it is a powerful means of describing the operation of forces. If you're using the word "why" to mean "for what purpose do magnets exist" (the same usage as "Why did you do that?"), then we can't answer that question except to note that magnets work because they obey the rules that govern the rest of the universe, and that those rules exist in concert; you can't change any of them without fundamentally altering how the universe works, and if you did that, then we wouldn't exist to study how magnets work in the first place (this is called the weak anthropic principle and is, philosophically, the best answer we have to "Why does <insert law of physics here> work the way it does and not some other way.") --Jayron32 12:37, 5 April 2013 (UTC)

All physical systems "prefer" to be in a state of lower energy. If they're not at a local minimum of the energy, there is a force on the system in the direction of decreasing energy. Magnetic fields have energy. If you superimpose two bar magnets oriented the same way, you get twice the field strength of one bar magnet alone, which gives you four times the energy (it goes like the field strength squared). If you superimpose them pointing in opposite directions, the fields cancel out and the energy is zero (or at least much smaller). If you separate the magnets by a large distance, they don't interact and the total energy is twice the energy of one alone. Therefore, magnets prefer being together with opposite poles touching to being far apart, and prefer being far apart to being together with like poles touching. -- BenRG 06:20, 7 April 2013 (UTC)

Now, I want to know whether a snail(or any species of snail) has 32 brains or not? 27.62.111.6 (talk) —Preceding undated comment added 12:39, 5 April 2013 (UTC)

It doesn't. It has six ganglia (see Jayron's answer above). The six ganglia, which you could have quickly discovered youself by googling "snail anatomy" are:

• cerebral ganglia (senses)
• buccal ganglia (mouthparts)
• pedal ganglia (foot)
• pleural ganglia (mantle)
• intestinal ganglia (organs)
• visceral ganglia

See http://animals.about.com/od/mollusks/ig/World-of-Snails/Anatomy.htm.

Note that if you consider the ganglia that handle external senses and decides what action to take as the brain, then snails have one brain though in a snail that's stretching things somewhat. Note also that if you consider any significantly large interconnected cluster of nerves as a brain, then humans have four brains:

• the large cluster in your head that you think with
• the CNS comprising the spinal cord (which can easily be shown to have significant reflexes and some decision making capability - for instance the muscular cycle of walking arises in the spinal cord, not in your head) and part of what's at the top of it
• the ganglia located in and controlling the heart
• the coeliac ganglia controlling digestion. It is not commonly realised among people who are not medical specialists that the number of nerve cells in the human digestion ganglia is very large, and it can be shown by experiment to have considerable learning capability. For instance, if you are in the habit of eating 3 small/moderate meals 6 days a week, and a very large meal Sunday lunch time, and no evening meal for instance, the coeliac ganglia will set you up to optimally handle that. Try eating that Sunday roast for Wednesday breakfast and see how you get on. But if that's what you usually do, you'll be fine.

Wickwack 121.221.88.3 (talk) 14:39, 5 April 2013 (UTC)

Right. Nearly every animal has a nerve cord running the length of its body, with regularly spaced cell clusters called ganglia. The ganglion at the front is called the brain -- it is usually larger than the others and has special properties. Some types of worm also have an enlarged ganglion at the rear that is sometimes called a "tail brain". But that's about it, except when people speak euphemistically. Incidentally, our brain article covers all of this. Looie496 (talk) 14:50, 5 April 2013 (UTC)

• I am still waiting for the lurid description.... μηδείς (talk) 17:38, 5 April 2013 (UTC)

• Did you see mine ? StuRat (talk) 21:51, 5 April 2013 (UTC)

If you are not satisfied with StuRat's description, see http://www.holysmoke.org/wb/wb0195.htm. Wickwack 120.145.202.43 (talk) 01:43, 6 April 2013 (UTC)

Chemistry

The oxidation state of chlorine in potassium chlorate is? — Preceding unsigned comment added by 41.220.68.33 (talk) 13:04, 5 April 2013 (UTC)

...a good question I ask my students for homework. Our oxidation state article might be a good place to learn how to figure it out.. DMacks (talk) 13:11, 5 April 2013 (UTC)

Universal life cycles

Is there scientific evidence that there are sun and moon-derived cycles that directly affect human behavior, yearnings and aspirations? If so, is this (in part) a result of our bodies sharing atomic structures common within the universe? — Preceding unsigned comment added by 98.248.153.47 (talk) 14:10, 5 April 2013 (UTC)

There is plenty of evidence of sun cycles affecting human behavior, but it has nothing to do with having "atomic structures in common within the universe," it has to do with the fact that pretty much all aspects of life on this planet are in some was affected by the amount of radiant energy that is coming from the sun (e.g. the weather). The moon is a convenient time-keeper and its movement affects the tides. But I don't think either of these are the kind of New Age sorts of explanations you are looking for. Just having atoms in common with something doesn't mean that you can mutually affect it. --Mr.98 (talk) 14:14, 5 April 2013 (UTC)

Lunar effect should cover it. Anecdotally, being related to nurses, it is a "Well Known Fact" that emergency admissions in the UK peak during the full moon. I'll try and find a news story related to it. --TammyMoet (talk) 17:51, 5 April 2013 (UTC) I knew I'd seen something about it relatively recently: this article summarises some research. --TammyMoet (talk) 17:59, 5 April 2013 (UTC)

You don't need to go for anything as unusual as the lunar effect. Of course the Moon has an effect on human behavior. For example, people think a full Moon is romantic and go out on dates around that time. If the Moon didn't exist, that wouldn't be the case. Also, people trip, fall, and hurt themselves during New Moon, but not as often during Full Moon. --140.180.248.141 (talk) 18:45, 5 April 2013 (UTC)

See also http://skepdic.com/fullmoon.html for a comprehensive summary. Also, the myth about a correlation between birth rate and moon cycle and/or tide has been clearly and repeatedly disproved. Cacycle (talk) 09:35, 6 April 2013 (UTC)

As a clerk in an ED, I can confirm nurses often blame busy shifts on "the full moon." Even when it's not a full moon. They've also decided that ordering Chinese food guarantees a bad day, and never say the word "code" or "trauma" because then we'll get one.

Now, most of the nurses aren't serious about it. It's just a simple way to vent stress at something that can't really be hurt. — The Hand That Feeds You:^Bite 20:21, 7 April 2013 (UTC)

People also fish according to the lunar cycles, and some outdoor activites become possible at night only when that little bit of lunar illumination is availible, so that might affect the rates of emergency room visits too. 202.155.85.18 (talk) 03:55, 8 April 2013 (UTC)

Elephants and sign language

Our Article says elephants are really smart, like dolphins or smarter. Is it possible to teach an elephant to speak Sign language? (some modified version of it - using trunk). Like Koko the Gorilla or better.

Has someone tried to do it? --Zhitelew (talk) 14:27, 5 April 2013 (UTC)

I'm not aware of any definitive reference, but it would be very surprising if it were not possible to to teach signed symbol recognition, but the construction of a signed grammar is not likely possible. If you consult the reference cited in the Wikipedia article (Ref 5), it says: For 27 years she has lived among savanna elephants in Kenya's Amboseli National Park studying their behavior and methods of communication. Poole has found that the elephants use more than 70 kinds of vocal sounds and 160 different visual and tactile signals, expressions, and gestures in their day-to-day interactions, which is comparable to dogs. Being a dog owner myself, I can say from experience that it is easier to teach dogs (the large breeds at least) a comprehensive signed vocabulary for human-to-dog communication than it is to teach them spoken commands. And they certainly use a comprehensive set of expressions and body language to communicate back, should you care to pay attention (for example, ears down and walking to the side of you means "greetings, favorite/family person".

What primates can be taught, dogs cannot, and elephants probably cannot, is a grammar - i.e., "Give Koko fruit", or "No want fruit" as distinct from just "fruit" or "no".

When trying to evaluate the intelligence and communication abaility of animals, you need to remember two crucial things: a) emotions like anger, happiness, etc are universal to the animal kingdom, and are not unique to humans (contary to what some religious nuts would have you believe), and remarkably few neurons (like less than 10) are necessary to demonstrate a full range of emotions - as shown over 50 years ago by Gray Walter and other workers; b) there is something about the DNA of vertebrate animals that results in a brain volume or mass roughly in proportion to body surface area. A large animal needs are large brain to handle the stimuli and muscle control consequent to a large body. Humans are notable exceptions to this rule (known as the encephalisation quotient) - we have immense brains for our body surface area. Elephants most certainly do not. Not to be forgoten is that humans do much of their conceptual thinking very slowly - and that most likely makes our brain size go further. A large brain in a large animal such as a whale or an elephant does not necesarily mean high intelligence. The size is much dictated by the above rule, and much of it may be inefficiently utilised, or may be utilised for situational memory. Human brains need comparitively small volume for extensive lifetime memory because of our high conceptual powers. We don't remember the details of situations, we encode concepts and remember them.

Wickwack 121.221.88.3 (talk) 15:13, 5 April 2013 (UTC)

I am not sure why you attribute the denial of animal emotions to "religious nuts", when it is behaviouralists and doctors of an older generation who denied animals and newborns were conscious or experienced pain or actual emotions. This traditional denial by scienticians is all over the literature. μηδείς (talk) 17:36, 5 April 2013 (UTC)

Do you have a source? Also, who would you say is responsible for denying animal emotions today, as opposed to generations ago? --140.180.248.141 (talk) 19:38, 5 April 2013 (UTC)

Probably people who would feel guilty about what they do to animals, otherwise; like whalers, hunters, those who work in slaughterhouses or animal research labs, etc. StuRat (talk) 22:01, 5 April 2013 (UTC)

They tend not to be so articulate, passionate, and so noisy as those "deep south" religious types, though. Wickwack 120.145.202.43 (talk) 00:40, 6 April 2013 (UTC)

Any book you want to read on animal consciousness written in the last 20-30 years will do, like by Temple Grandin or Monty Roberts. Searle will give you good criticisms on behavioralism as applied to humans. Simple google searches on "do animal have emotions" and "do newborns feel pain" will get you everything you want. I don't understand the "who would you say is responsible" question. μηδείς (talk) 00:27, 6 April 2013 (UTC)

This is not a forum for posting a rant against behaviorist. Feel free to add a source, if you got any. OsmanRF34 (talk) 17:52, 5 April 2013 (UTC)

Emotion in animals has it all explained. Whether animals have emotions like happiness or not is far from uncontroversial. I suppose it's difficult to deny that mammals feel pain, however. OsmanRF34 (talk) 17:55, 5 April 2013 (UTC)

It would be hard to deny that a dog that is welcoming it's owner home after a week of absence with wild tail wagging, jumping, licking, etc isn't "happy". Sure it's possible that this is some bizarre behavioral thing that doesn't contain the underlying emotion - but how can you tell that your next door neighbor is "happy" and not just exhibiting some complex behavioral trick? SteveBaker (talk) 19:36, 5 April 2013 (UTC)

No, I cannot prove that my neighbor can feel something comparable to my feeling of happiness, and I don't deny that dogs have a whole plethora of feelings, and some of them could be called happiness. But how can I tell that a dog can have the same feeling of happiness which is not connected to any physical sensation, just caused to the realization that things are like you expect them to be? Some feeling in humans arise due what we know and to what information we get. Animals, contrary to my neighbor, process information in a quite different way, should I expect that they also feel some sort of existential anxiety like humans? OsmanRF34 (talk) 21:42, 5 April 2013 (UTC)

"Emotions" is kind of a stretch when applied to animals. As a pet owner, I'm more inclined to use the term "moods"; that is, is the animal feeling good, or not so good. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:24, 5 April 2013 (UTC)

Likewise, many animals also undeniably form interpersonal and social bonds, regardless of whether you interpret it from a strictly behaviourist perspective or consider it something akin to the attachment and affection we feel. Well, presumably we, since the existential question has been raised, but I for one accept it for a given...because, you know, I'm not a community college philosophy professor to dwell on the question of whether it might be otherwise - I've decided to get on with my life under the assumption that other people, and with some variation other creatures, have "genuine" emotions whose definitiveness is only limited by the same constraints I'd put on my own. But then, coming from a more contemporary (and biologically informed) perspective in the cognitive sciences, I tend to view the more absolutist approaches to behaviourism as more than a little flawed and antiquated. But we've surely strayed from the OP's point (even if we are barely still in the same nieghbourhood). Snow (talk) 08:32, 6 April 2013 (UTC)

Elephants already speak in sign language with their trunks and body gestures. They also vocalize, which anyone visiting a zoo at feeding time can see. The question is really "can elephants be taught to communicate with humans, in a human defined method of language?" Sure they can. Most animals can be trained to do many things. The thing they can't do, however, is to use those communication tools to express ideas, or to conceptualize, beyond the things that they were taught. Koko was so amazing because of the fact that she started to show sings of furthering her abilities on her own, but even that is still debated. As far as animals and emotions go, well, we can barely define the term happiness or sadness between two humans, much less different species. In my observations, most animals are either distressed, excited, or somewhere in the middle. I can assure you my dogs are "happy". Whether that happiness occasionally brings them a feeling of "joy" or not, I will never know, and I don't think anyone ever will. Ditch ∝

biology

after fertilisation if uterus is removed from the body of female,what will happen? — Preceding unsigned comment added by Titunsam (talk • contribs) 17:19, 5 April 2013 (UTC)

Does the uterus still contain the fetus? If so, then the fetus will die. If the fertilized egg is, like, 17 years old, it's probably fine, though... --Jayron32 17:22, 5 April 2013 (UTC)

What will happen to the female? Or to the embryo/fetus/baby? OsmanRF34 (talk) 17:41, 5 April 2013 (UTC)

Also, for the sake of completeness, the removal of a uterus is called a hysterectomy. --Jayron32 20:39, 5 April 2013 (UTC)

I wonder, after re-reading the question, whether the OP meant: what happens after fertilization, when the uterus was removed? At first I thought that the ovaries are also removed during a hysterectomy (i.e. an oophorectomy was performed during a hysterectomy) , but that's not always the case. So, after removing the uterus, fertilization can result in rare occasions in an ectopic pregnancy.OsmanRF34 (talk) 21:57, 5 April 2013 (UTC)

I find it very hard to see how sperm can make the jump from the vagina to the Fallopian tubes, when all the ends are sewn up separately. They don't connect the vagina to the Fallopian tubes when the uterus is removed, assuming they leave them in place. The ovaries are not physically connected. --TammyMoet (talk) 10:46, 6 April 2013 (UTC)

It's very rare, but possible: WK has the explanation: "Removal of the uterus without removing the ovaries can produce a situation that on rare occasions can result in ectopic pregnancy due to an undetected fertilization that had yet to descend into the uterus before surgery. Two cases have been identified and profiled in an issue of the Blackwell Journal of Obstetrics and Gynecology; over 20 other cases have been discussed in additional medical literature." OsmanRF34 (talk) 13:22, 6 April 2013 (UTC)

Thanks for that - but just to make clear, except in situations where an undetected fertilisation was still in the Fallopian tube, pregnancy from unprotected sex cannot happen after hysterectomy. --TammyMoet (talk) 13:59, 6 April 2013 (UTC)

That makes a lot more sense, but is it possible that they could botch the operation and somehow a sperm could find its way to the right place? ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:24, 6 April 2013 (UTC)

I don't see how. Even if somehow they failed to seal both the vagina and an ovary, there's no "path" for the sperm to follow. Further, sperm has a very low lifespan after it exits the male body. Chances of one being able to slog along other tissue to reach the exposed ovary are virtually zero.

Also, the woman would be experiencing some pretty nasty bleeding if they failed to seal the vagina. — The Hand That Feeds You:^Bite 20:40, 7 April 2013 (UTC)

The lifetime of an alpha particle compared with that of the proton

ive heard the [free or otherwise] proton may decay, with a very long halflife like 10^40seconds. Now the free neutron lasts justs a few seconds. Well, could alpha paricles be even more stable than protons, just as neutrons seem to last longer (or "pass the hot potato" to another nucleon when about to decay??) inside most nuclei? Thanks, Rich.199.33.32.40 (talk) 20:14, 5 April 2013 (UTC)

AFAIK, the alpha particle is essentially stable over any arbitrarily long time span. Helium-4 discusses the stability of the particle some, and the He-4 nuclide is noted on all of our various lists of nuclides (including List of nuclides and List of elements by stability of isotopes) as not having a known half-life, which would count as "about as stable as can be found". --Jayron32 20:30, 5 April 2013 (UTC)

Unlike the the Neutron which may decay more slowly when found within a nucleus, The proton's lifetime really isn't affect by it's environment (except in the case of a beta plus decay in which the proton decays into a neutron,m but that's a different matter entirely. Dauto (talk) 19:27, 6 April 2013 (UTC)

If the lifetime of a lone proton is finite, alpha particles will decay by the same process with a slightly shorter half life (since any one of the four nucleons can decay). Alpha particles should also be subject to sphaleron decay, unlike lone protons, but the half life for that is ridiculously long. In a recent thread Count Iblis said the half life for sphaleron decay of a deuteron is 10²¹⁸ years, but I don't know where he got that figure. Either way, alpha particles definitely have a shorter lifetime than protons. -- BenRG 05:53, 7 April 2013 (UTC)

So is there no possibility that the halflife of the protons are lengthend by their inclusion in the alpha particle, by analogy to neutron's halflife being lengthened by being in a nucleus? 202.155.85.18 (talk) 03:50, 8 April 2013 (UTC)

Thanks to all.-Richard Peterson76.218.104.120 (talk) 03:27, 9 April 2013 (UTC)