Wikipedia:Reference desk/Archives/Science/2009 December 10

= December 10 =

sulfoxide functional groups in drugs
Is the primary fate of sulfoxides to interact with cysteine residues in enzymes to form sulfide-sulfide bonds? John Riemann Soong (talk) 01:28, 10 December 2009 (UTC)

L1 Lagrange point
The Lagrangian point article states, "The Earth–Moon L1 allows easy access to lunar and earth orbits with minimal change in velocity and would be ideal for a half-way manned space station intended to help transport cargo and personnel to the Moon and back."

As far as I can tell from some of the external links at the article, L1 is past the orbit of the Moon. For some reason this example point isn't spelled out in the article though others are. I had to go looking elsewhere to see where L1 is in relation to the moon's orbit. So, could someone explain, more completely and in fairly basic terms (i.e. I'm not an amateur astronomer), why a point which is past the Moon's orbit would be a good half way point for going to the moon? Thanks, Dismas |(talk) 03:51, 10 December 2009 (UTC)
 * This is the Earth-Moon L1, which is of course between the Earth and the Moon. You're thinking of the Earth-Sun L1. Algebraist 03:57, 10 December 2009 (UTC)
 * Ah! Right.  Got it.  Sorry for that...  I must have read it too quickly.  Dismas |(talk) 03:59, 10 December 2009 (UTC)

I'm suspicious of the claim, though. The Earth-Moon L1 point is about 5/6 of the way to the moon, and the amount of energy required to get there from here is pretty close to the amount to get all the way to the Moon. In what way would it be logistically useful to stop there? --Anonymous, 04:31 UTC, December 10, 2009.


 * It may be 5/6 of the way by distance, but distance isn't really relevant in the context of space travel. Since there is minimal drag in space, you can get pretty far without having to exert any force (spend any energy) which is what costs fuel/money.  From the first line of this question, quoted from the article, you can see that by definition, the Lagrangian point has minimal change in velocity to switch from an Earth orbit to a moon orbit.  Change in velocity = acceleration = force ~ cost.  moink (talk) 09:44, 10 December 2009 (UTC)


 * First, the relevance of the distance from Earth is that it determines the energy requirement to get there from here, i.e. how high you have to rise in the Earth's gravity well. Second, the cost of switching from "an" Earth orbit to "a" Moon orbit isn't important; what matters is the cost of switching between useful orbits.  --Anonymous, 10:37 UTC, December 10, 2009.


 * The tight linkage between distance traveled and energy expended (e.g. on Earth's surface) is due to the need to overcome friction, wind resistance, etc. Moving with constant momentum in a vacuum where gravity is negligible would require nearly zero energy.  Add gravity, and the energy required is related to work done against gravity, with distance playing a role only as it relates to the force of gravity.  Thus, when talking about the energy required to move in space, distance is not as relevant as intuition might suggest.  Of course, distance will affect the time required to make a trip, in a velocity-dependent way.  -- Scray (talk) 11:49, 10 December 2009 (UTC)


 * For the third time, I'm talking about the distance only in relation to the force and energy required to overcome (the Earth's) gravity. --Anonymous, 21:33 UTC, December 10, 2009.


 * By definition, L1 lies on the path where you increase the least relative to Earth's gravity well before falling into the Moon's gravity well. Dragons flight (talk) 12:23, 10 December 2009 (UTC)


 * Correct, but velocity is relevant as well as position. To make a stop at L1 you must expend energy to enter an orbit matching L1, then more energy to get moving toward the Moon again.  --Anonymous, 21:40 UTC, December 10, 2009.


 * By its nature, both Earth and the Moon are "downhill" from L1. Yes, if you're stopped at L1, you need to expend energy to get moving again, but since an orbit at L1 is an unstable equilibrium, any expenditure of energy, no matter how small, is sufficient. --Carnildo (talk) 00:40, 11 December 2009 (UTC)
 * Very true. However, the point about the difference between "an orbit" and "a useful orbit" is a very good one - a small expenditure of energy would get you into a very high orbit around either the Earth or the Moon, neither of which is very useful. --Tango (talk) 17:10, 11 December 2009 (UTC)

Assume an initial geocentric elliptical orbit with its apogee close to L1 and its perigee close to Earth's surface. The perigee could be raised by several flybys of the Moon (or should I say the Earth-Moon L1 point) with a carefully selected trajectory... Then the relative velocity would be small and the spaceship could enter a lunar orbit using only little rocket fuel (sometimes such slow transfers are called the "Interplanetary Transport Network"). In order to be even more fuel-efficient, we would have space elevators both at Earth (with its top above the geostationary orbit) and at the Moon (with its top above the Lagrange point). Icek (talk) 07:34, 13 December 2009 (UTC)

Known changes: mental function: adulthood
What is known about changes of a physiological sort and also perhaps a behavioral sort that occur in the brain and in the minds of people in the years between the beginning of adulthood and the beginning of old age? These points may be poorly defined, especially "old age." But I seem to recall seeing a lot written on how these things change through childhood and perhaps into early adulthood. And it is known that age significantly correlates with the mental decline seen in some older people. But is anything known about any changes that transpire in the forty or fifty years in between these two points? Bus stop (talk) 04:17, 10 December 2009 (UTC)
 * Gerontology is the study of ageing. Developmental psychology has something to say about psychological changes associated with adulthood. --TammyMoet (talk) 10:08, 10 December 2009 (UTC)

Although I am old there is nothing wrong with my short term memory nor is there anything wrong with my short term memory.Cuddlyable3 (talk) 21:23, 10 December 2009 (UTC)

Life Expectancy in 2050
What will the life expectancy of the world be in 2050?

What will the life expectancy of America be in 2050?

What will the life expectancy of Australia be in 2050?

Bowei Huang (talk) 05:06, 10 December 2009 (UTC)


 * Wikipedia is not a crystal ball. That being said, I would guess that it wouldn't be much higher than today because the life expectancy of those countries seems to be close to the maximum life span.  J kasd  08:35, 10 December 2009 (UTC)
 * Wikipedia might not be a crystal ball, but others have made estimates. If you want to see more examples, look on Google News and Google Scholar. Fences  &amp;  Windows  15:19, 10 December 2009 (UTC)
 * I answered a very similar question at the Miscellaneous desk and the U.S. census source I give there also does future projections. SO the answer there will also answer this question.  -- Jayron  32  16:25, 10 December 2009 (UTC)

But what if we don't talk about the life expectancy of America or Australia, we just talk about the life expectancy of the world? What are the projections for the world's life expectancy in 2050?

Bowei Huang (talk) 23:49, 10 December 2009 (UTC)

Bowie Huang: Go to the miscellaneous desk. Find the very similar question you asked there. Click the link I gave you for the U.S. Census Bureau's International Database. Follow the instructions I gave there to find the data you are looking for. It has data for the USA, for Australia, and for the whole world, and for every year going back a long time, and for projections for many years into the future. Its all there. Trust me. You don't have to keep asking. It's all there for you to find. -- Jayron  32  05:43, 11 December 2009 (UTC)

E.V.S. project
Which topic is good for e.v.s project? —Preceding unsigned comment added by 117.200.178.181 (talk) 06:55, 10 December 2009 (UTC)
 * What is an EVS project? Dismas |(talk) 06:59, 10 December 2009 (UTC)
 * Perhaps European Voluntary Service? AndrewWTaylor (talk) 09:22, 10 December 2009 (UTC)

why is Potassium chloride caustic if its ph   is 7  ?
do you guys  know? —Preceding unsigned comment added by 74.65.3.30 (talk) 10:21, 10 December 2009 (UTC)


 * It isn't. The burning sensation you feel if it gets into an open wound is a consequence of potassium triggering the exposed free nerve ends (somebody correct me if I'm wrong). Both potassium and chloride potentials are important components of the electrical balance in nerve cells. — Yerpo Eh? 10:28, 10 December 2009 (UTC)


 * In addition to Yerpo's point above, any water-soluble salt or concentrated salt solution (including regular old sodium chloride: table salt) will cause discomfort in an open wound. The high salt concentration outside the body's tissues will draw out water, causing a localized osmotic stress and triggering pain. TenOfAllTrades(talk) 14:42, 10 December 2009 (UTC)


 * Also note that Potassium Chloride, unlike Sodium Chloride, is very damaging to skin and tissue and does not promote healing but rather the opposite. A wound will not heal if kept exposed to Potassium Chloride and exposure of the intestinal track to Potassium Chloride will cause ulcers. The reason may be linked to the fact that the primary extracellular ion is Sodium, not Potassium, correct me if I am wrong. 71.100.160.161 (talk) 17:42, 10 December 2009 (UTC)
 * Potassium chloride is a common ingredient in salt substitutes, so in similar quantities to sodium chloride, would not be likely to cause adverse effects in human consumption. Googlemeister (talk) 20:29, 10 December 2009 (UTC)
 * Next time you get a cut or abrasion don't do a reality check by using potassium chloride as an antiseptic or to cover and protect the wound even if you believe your opinion is fact. 71.100.160.161 (talk) 22:08, 10 December 2009 (UTC)
 * Don't credit me for things I did not write. I say nothing about skin application, only that your statement that potassium chloride causes ulcers when eaten is demonstrably false when consumption is of the same magnitude that one would eat sodium chloride.  Googlemeister (talk) 22:20, 10 December 2009 (UTC)
 * People use salt to cleanse wounds all of the time. The Potassium in foods like bananas is relatively safe if you do not eat too many. Your taste buds, however, can tolerate a great deal more than your intestines. There are two types of salt substitute. One is an approximate 50/50 mix of Sodium and Potassium. The other is all Potassium. What is needed are warning labels. .7 grams per liter of water is the limit for the 50/50 mix. .7 grams of the 100% and you will begin to have pain in your gut. 71.100.160.161 (talk) 22:50, 10 December 2009 (UTC)

why is potassium chloride damaging to the skin if its ph is 7  isint that neutral?


 * Osmolarity. Take a look at the top picture (left most panel) in the hypertonic article and imagine that's what's happening to your skin cells. -- 128.104.113.17 (talk) 17:28, 11 December 2009 (UTC)

There's also the fact that potassium depolarises cell membranes. (Extracellular potassium levels are supposed to be low whereas extracellular potassium levels are supposed to be high.) Like you know why intravenuous potassium chloride is a method for executions. John Riemann Soong (talk) 22:27, 11 December 2009 (UTC)

Since of touch
How fast does it travel? And how does it does so so fast that when you touch something, you immediately feel it?Accdude92 (talk to me!) (sign) 14:47, 10 December 2009 (UTC)


 * It's not instantaneous—it's as fast as your nerves can transmit the signal and your brain can make sense of it (though some types of sensations—like extreme pain—can be processed without your brain fully understanding them, and responded to with a reflex, if I recall). Reaction time is probably a good place to start. --Mr.98 (talk) 14:55, 10 December 2009 (UTC)


 * See Axon for signal travel speed. It depends on the fiber myelination. --Mark PEA (talk) 15:09, 10 December 2009 (UTC)

Measuring magnetic susceptibility
Is a Gouy balance the same thing as a Faraday balance? They are both used for measuring magnetic properties. Alaphent (talk) 16:35, 10 December 2009 (UTC)


 * We have an article on Gouy balance. The Faraday balance method is very similar with the difference being in the size of the sample.  In the Faraday method, a small sample (essentially a point) is balanced in a graded magnetic field.  In the Gouy method, the magnetic field is constant but the length of a sample rod in the field is varied. This book shows the difference diagramatically.  Sp in ni  ng  Spark  19:08, 10 December 2009 (UTC)

ammonia sanitizer
I understand that the meat processing industry uses anhydrous ammonia to kill e-coli and other meat product contaminants by sealed exposure to the gas. Is this really done, does it work and is it harmful to the meat products or to consumer? 71.100.160.161 (talk) 17:33, 10 December 2009 (UTC)
 * It seemingly is done, and works, according to Section 7.4.4 of the article you yourself linked to, which also says that the US Department of Agriculture says it's safe. Now, how far do you trust them? 87.81.230.195 (talk) 01:57, 11 December 2009 (UTC)

Sodium bicarbonate ph?
why the ph listed on this site as a 10 when it is really  a 8  ? —Preceding unsigned comment added by 74.65.3.30 (talk) 17:56, 10 December 2009 (UTC)


 * Solid sodium bicarbonate has no pH. pH is the property of a substance when it dissolves in water.  pH is a measure of the concentration of something called hydronium ions in water.  pH is based on a negative logarithm scale, which means that small numbers indicate a higher concentration of hydronium, and larger numbers indicate a smaller concentration.  It also means that each increase of 1 on the pH scale means a factor of 10 in concentration, so a pH of 1 has 10 times the concentration of hydronium as does pH 2, and 100 times the conentration as pH 3.  Now, depending on how much sodium bicarboate you add to water will effect how much hydronium it makes, which will then affect the pH.  A 1.00 molar solution of sodium bicarbonate has a pH of 10.3, but if you had a more dilute solution, the pH would be closer to that of water (ph = 7) while a more concentrated solution would result in a pH farther from water.  -- Jayron  32  20:08, 10 December 2009 (UTC)


 * Please tell us which site lists Sodium Bicarbonate as pH 10 or 8. It does not seem to be the Wikipedia article.Cuddlyable3 (talk) 21:03, 10 December 2009 (UTC)


 * The Wikipedia article lists the pKa as 10.3... Presumably, the OP confused the terms pKa and pH. I may have too, now that I look at my reasoning.  The half-equivalence point of a solution of sodium bicarb will have a pH of 10.3, not a 1 molar solution.  Regardless, the OP seems to have a general misunderstanding of how pH works.   -- Jayron  32  21:19, 10 December 2009 (UTC)

so why dosent the wiki article just list the real ph? in fact on wiki most chemicals here dont have a ph listed. why?


 * Did you actually read anything I wrote, or even click the links and read the articles? pH refers to a very specific property of a very specific type of thing.  It is specifically the amount of hydronium ions created when you dissolve something in water.  That amount of hydronium ions is going to be dependent on how much you dump into the water.  Nothing has an inherent pH.  Its not a property of a substance, its a property of a mixture between a substance and water.  If you dump two scoops of sodium bicarbonate in water, the mixture will have a different pH than if you dump one scoop of sodium bicarbonate in water.  -- Jayron  32  05:40, 11 December 2009 (UTC)

yer a fucking idiot if i take baking soda POWDER to a lab and ask them the ph they will tell me. quick lime ph is like 11 and ITS A FUCKING POWDER U IDIOT —Preceding unsigned comment added by 74.65.3.30 (talk • contribs)


 * No, they don't tell you the pH of a powder because powders do not have a pH. Read the article titled pH.  The first line of that article is "pH is a measure of the acidity or basicity of a solution".  You should also probably read what a solution is, if that doesn't make sense to you.  And typing in all caps and calling people names doesn't make you right.  It just makes you look rude.  -- Jayron  32  06:37, 11 December 2009 (UTC)


 * No need for name-calling. You say "if i take baking soda POWDER to a lab and ask them the ph they will tell me.  quick lime ph is like 11". Please actually do this. Let us know what lab and what they tell you. DMacks (talk) 06:58, 11 December 2009 (UTC)

Since this was an issue which I noticed when searching on this, can someone look into Talk:Sodium_bicarbonate Nil Einne (talk) 10:31, 11 December 2009 (UTC)

To be fair, before I'd really got a handle on what pKa was, the WP articles on acids etc confused me too. I know that it's obviously not useful to put up pHs of various solutions, but I think the OP has fallen into a fairly common hole that lurks within the chemistry articles. Brammers (talk) 10:35, 11 December 2009 (UTC)
 * The chembox entry link points to Acid dissociation constant, so (assuming people actually click a link before assuming what a term means) that is the page that needs to be very clear very early what the difference between the acidicity of a "chemical in solution" vs the acidity of a "solution of a chemical". DMacks (talk) 10:47, 11 December 2009 (UTC)


 * The deal is, with acid-base chemistry, it is pretty complicated. I think I did my best to explain what pH is above, but really, consider that we have three theories of acid-base chemistry, and they ALL serve their purpose (Arrhenius theory, Brønsted–Lowry theory, and Lewis theory).  If people arrive at Wikipedia with a misunderstanding of what pH is, all we can do is attempt to correct the misunderstanding in terms they are likely to understand.  If the articles that exist at Wikipedia need fixing in order to make them clearer lets do that too.  This was a case of someone just being rude for its own sake.  I patiently explained in two different ways how pH worked, and got called a "fucking idiot".  I don't know that the person who asked the question is in the proper frame of mind to be educated, given his response.  -- Jayron  32  17:04, 11 December 2009 (UTC)

should a shit blanket go over an awesome one or vice versa?
if I have a shit excuse for a blanket and also an awesome Taj Mahal of blankets, would I optain optimum warmth by putting the shit excuse for a blanket over me and the Taj Mahal over that, or vice versa? What is your reasoning. 92.230.69.195 (talk) 19:20, 10 December 2009 (UTC)


 * It makes little difference in warmth but it may make a difference in confort. Which one makes you feel ichyh? Dauto (talk) 19:49, 10 December 2009 (UTC)


 * It should make little difference if they are both intact. If the shitty blanket has holes in it, allowing for convection, you would probably be warmer is that is on the inside.  Dragons flight (talk) 19:55, 10 December 2009 (UTC)


 * (ec)It depends on what makes it shitty. If it just had holes in it, I think that could conceivably improve the usefulness of the under-blanket as it wouldn't detract from the layer of warm air accumulating under the covers and might actually allow some additional circulation of air to lessen the sweats. On the other hand, it it's shitty because it's starchy or plastic-y, it might be better on top because the starchiness might interfere with circulation and/or feel scratchy. Matt Deres (talk) 19:58, 10 December 2009 (UTC)
 * "what is your reasoning" With a title like "should a shit blanket go over an awesome one or vice versa" thank *god* there is a reasoning requirement!  But seriously, there are many factors to measure blanket effectiveness, you need to be more specific.  As an avid camper that spends nights in a thin tent at sub 0F temperatures, I would say that the wind/water impermeability is paramount for the outermost layer (meaning it stops cold air/water from getting in), whereas the inner layers are measured by their fluffiness (meaning they better insulate the heat inside).  Hope this helps! --66.195.232.121 (talk) 21:03, 10 December 2009 (UTC)


 * When in the past I slept in a cold room under blankets, I noticed that I would feel warmer if I put something over the blankets that stopped the warm air from rising up and escaping. Similarly, a sleeping bag inside a large plastic bag is warmer (beware suffocating, and you get lots of condensation). So put the most wind-proof one on top. 89.242.147.237 (talk) 23:04, 10 December 2009 (UTC)

Rubbing salt into the wound
I'd always assumed that when salt was rubbed into the wounds of chimney-sweeps, for example, they were causing them pain (an osmosis-based pain, WP says) but also doing them a favour of some kind, perhaps antiseptic or similar. Is this correct, or was it just sadism? - Jarry1250 [Humorous? Discuss.] 20:19, 10 December 2009 (UTC)
 * The hyperosmolarity is the cause of the antiseptic effect.  Wisdom89  ( T |undefined /  C ) 21:30, 10 December 2009 (UTC)

The Future Is Wild
is The Future Is Wild made by Amasia when the supercontinent is all Atlantic Ocean or is it like Pangaea Ultima. Will The Future Is Wild shows when all pacific Oceans close?--209.129.85.4 (talk) 20:24, 10 December 2009 (UTC)

atom "melting" temp
What temperature would it take to literally rip an atom apart, that is the nucleus flies apart and the electrons are lost, leaving only random bits of subatomic particles? I mean sure temperature is something like how fast atoms or molecules are moving and vibrating and such, surely some temperature would be large enough that atoms are moving fast enough the forces holding the atom together are no longer sufficient? Googlemeister (talk) 21:26, 10 December 2009 (UTC)
 * A wild guess: look at the binding energies. 1–9 MeV corresponds to temperatures of 12–104 GK.  --Tardis (talk) 21:43, 10 December 2009 (UTC)


 * (ec) That's one of those questions whose answer will depend heavily on how it is interpreted. Some radioisotopes will fission spontaneously at room temperature; does that meet the minimum standard?  At the other extreme, the binding energy of an atomic nucleus is the (hypothetical) amount of energy required to pull all of its nucleons apart into separate particles.  Figure it's 7 or 8 MeV per nucleon (neutron or proton), and the energy of a nucleon at temperature T will be (very roughly) on the order of kBT.  In that case, the whole thing drops apart at around 1011 kelvin (that's 8 MeV divided by kB).

The thermal energy of each particle will be roughly equal to the energy with which it would be bound to the nucleus &mdash; which is probably closer to the sort of answer you're looking for. Note that I'm back-of-the-enveloping things here, so if anyone has a better answer, go to it. TenOfAllTrades(talk) 21:48, 10 December 2009 (UTC)


 * (also ec)
 * Even in extreme conditions, subatomic particles don't group themselves at "random"; they have a strong tendency to collect in specific groups that form the nuclei of the stable elements and their isotopes. If you start with the nucleus of a radioactive isotope, it'll be unstable no matter what the temperature; for example, a nucleus of radium 226 will sooner or later rip itself apart, all by itself, into a helium 4 nucleus (otherwise called an alpha particle) and a radon 222 nucleus.  This will continue with the radon nucleus emitting another alpha particle, and so on until all of the products are stable nuclei.


 * If you raise the temperature, stable nuclei will start colliding and break up in other ways, or fusing together. But each specific reaction requires a different amount of energy (because of the tendency of particles to collect in specific groups) and therefore a different temperature.  Thus for example inside the Sun the core temperature is about 15,700,000 K or °C (say 28,000,000°F).  At this temperature collidign nuclei will produce certain fusion reactions with the overall effect that four hydrogen 1 nuclei (i.e. protons) end up forming one helium 4 nucleus.  But no other important reactions occur at that temperature.  On the other hand, the core of a star that's about to become a Type II supernova contains iron 56 at 2,500,000,000 K or °C (4,500,000,000°F), and it's when this iron begins reacting that the star explodes (because the reactions absorb energy and the core collapses).


 * So the answer is basically "from the tens of millions of degrees up to the billions, depending on what element you're talking about".


 * That's for the disruption of nuclei. Electrons are lost at much, much lower temperatures, I think in the tens of thousands of degrees.  See plasma (physics).  --Anonymous, 22:12 UTC, December 10, 2009.


 * It depends on which electrons. The outermost electron only costs you between 5 and 25 eV (thousands or tens of thousands of degrees), but the binding energies of core electrons get into the hundreds of eV very, very fast.  (Each time you pull another electron off, there are fewer electrons remaining to screen the positive charge of the nucleus, and electrons in core orbitals are 'deeper' down to begin with.) TenOfAllTrades(talk) 22:50, 10 December 2009 (UTC)
 * But the limit is still about 136 keV ($$Z\lesssim100$$, squared, times the Rydberg constant), which is still much smaller than even deuterium's per-nucleon binding energy. --Tardis (talk) 23:12, 10 December 2009 (UTC)
 * Oh, absolutely! My point was more that you're not going to get fully-stripped nuclei until you hit millions of degrees, not that the core electron binding energies were comparable to nucleon binding energies.  (Indeed, if they were, we'd have some very interesting transmutation chemistry accessible to us....) TenOfAllTrades(talk) 23:39, 10 December 2009 (UTC)


 * This is one of the reasons, incidentally, that nuclear fission was so unintuitive to nuclear physicists. If you calculate based on binding energies alone, it should be VERY hard to make a large nuclei break apart—it should take very high energies. But, in fact, it takes low energy neutrons to do it (in U-235, anyway)... because it's not just about the binding energy alone. One physicist described it as throwing a softball at a house and watching the whole structure split into pieces. --Mr.98 (talk) 18:20, 11 December 2009 (UTC)

Free energy interpretation
I don't know why the Arrhenius equation is being used, since that is a kinetic thing, not a thermodynamic thing...? For the melting temperature you'd have to find the T where free energy of free nucleons = free energy of bound nucleus. Thus if an atom is unstable, you can thus see that even at say 300K, a tiny amount of the reactive species will exist at any one time. John Riemann Soong (talk) 22:13, 11 December 2009 (UTC)

Highest temperature
Was the moment of the Big Bang the moment of the highest temperature and if so by what curvature has the universe cooled? 71.100.160.161 (talk) 22:13, 10 December 2009 (UTC)
 * Read Planck temperature, Planck epoch and Absolute hot. The general relativity model predicts infinite temperature, but this formulation fails at the time period anyway. Graeme Bartlett (talk) 23:42, 11 December 2009 (UTC)

Miller–Urey-type experiments
Miller–Urey-type experiments with more realistic predictions about early Earth's atmospheric composition produce many amino acids, but they also produce deadly toxins such as formaldehyde and cyanide. Even if, by some freak chance, amino acids assembled themselves in the correct order to form usable proteins and then life, why wasn't early life killed off by these toxins that were formed at the same time? --76.194.202.247 (talk) 23:28, 10 December 2009 (UTC)


 * Firstly, the concentration of these toxic substances in the sea would not have been that great. Secondly, how do you know that these chemicals were toxic to early lifeforms? Pseudomonas aeruginosa, for instance, is known to be tolerant to hydrogen cyanide, indeed, it will synthesise this chemical in low oxygen conditions.  Escherichia coli is tolerant to formaldehyde. On the other hand, most early life was poisoned by oxygen and would not last 5 minutes if it was released now.  Life evolves to cope with the environment it finds itself in.  Sp in ni  ng  Spark  00:21, 11 December 2009 (UTC)
 * That. It's also worth mentioning, perhaps, that the earliest products wouldn't have been necessarily life as we know it, but rather just organic structures that could perpetuate themselves somehow.  That's something a lot closer to viruses, for example, than to a living multi-celled organism. ~ Amory ( u  •  t  •  c ) 02:07, 11 December 2009 (UTC)


 * You might want to have a look at our article on abiogenesis; it touches on some of the theories for how life came about. TenOfAllTrades(talk) 04:43, 11 December 2009 (UTC)