Wikipedia:Reference desk/Archives/Science/2007 July 12

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July 12

Record Player Sound

I have a copy of the same album on both CD and LP, and I noticed that the LP plays at a slightly higher pitch. The LPs and record player are in good condition, and I couldn't find an explanation at gramophone record. How can the higher pitch be explained? -- Sturgeonman 00:52, 12 July 2007 (UTC)

• Are you sure your gramophone is at the exact right speed? --jpgordon^∇∆∇∆ 00:55, 12 July 2007 (UTC)

Some record players have a stripey disk at the center of the turntable. This is designed so that if it's spinning at the right speed - under a regular room lamp (not a florescent), it will appear to be dead stationary. You can use that to verify that all is well with your turntable. But it certainly sounds like it's spinning a teeny-bit too fast. Most halfway decent turntables have a fine speed adjustment somewhere. I suppose it's just possible that when they recorded the LP, they speeded the master tape up a tiny bit so that they could fit the track onto the limited space on the LP...but I really doubt that. SteveBaker 01:56, 12 July 2007 (UTC)

Steve, why not a florescent lamp which I would have thought to be more "binary" than an incandescent lamp and thus show "strobe" effects more distinctly, no? ~ hydnjo talk 02:36, 12 July 2007 (UTC)

See phosphors and persistence of such to find answer. --Tugjob 02:57, 12 July 2007 (UTC)

I would have thought that the stroboscopic effect was more on target. ~ hydnjo talk 03:10, 12 July 2007 (UTC)

With regard to "ordinary" (presumably incandescent) lamps versus fluorescent lamps, nonsense. Maybe in the 50Hz world the flicker from an incandescent lamp is adequate to look at a strobe disk, but in the 60Hz world, you'll have a very hard time; the peak-to-trough variation in an incandescent filament just isn't deep enough. A fluorescent will give much better effects, especially if you recognize that the light is quite bluish when the arc is active and redish when it's just the phosphors glowing. But the strobe of choice is definitely a neon lamp or light-emitting diode powered from the mains through a rectifier (so it's only on a maximum of 50% of the time). This will give you very clear readings of the strobe disk. When turntable contained built-in strobes, it was almost always just such a neon lamp (with or without the rectifier).

Then again, how accurate is your mains frequency? While it's usually very accurate over the long-term (so electric clocks read correctly), you may find noticeable variations over the short term.

Atlant 13:04, 12 July 2007 (UTC)

Everything you say is OK - right up to the point where what I said is 100% true. Record turntables DO have those disks and they DO work perfectly well with incandescent lamps. Some florescent lamps work OK - some don't - it depends on the type of ballast circuitry they use. To be on the safe side - use a filament bulb - because even though they don't produce a deep modulation - it's plenty good enough for adjustment of a turntable (I used to be a volunteer DJ at a local hospital radio station - and I worked in student radio when I was in college - I've done this a bazillion times, under both 50Hz and 60Hz room lighting). You're right about small variations in mains frequency - but the errors are very small compared to the fairly poor precision of a typical turntable deck motor. At any rate - that is what you get with most turntables - a strobe that works off mains lighting. High end 'professional' decks often have a crystal clock to automatically adjust the speed - so they are every bit as accurate as CD players - but we may deduce that our questioner doesn't have one of those or we wouldn't be having this debate. SteveBaker 13:42, 12 July 2007 (UTC)

Ahh, you're speaking of electronic ballasts. Well, for the low-end (consumer-grade) ones that I've examined so far, the bulk-storage capacitor isn't large enough to store enough energy across a half-cycle of the mains to prevent all flickering, but I'll grant you that point; I was only thinking of old-style magnetic ballasts.

Atlant 15:11, 12 July 2007 (UTC)

Regarding the pitch, I can confidently say that the gramophone player is turning a bit too fast. I am equally confident that there will be a small knob / lever to adjust the speed. Regarding the stroboscopic effect, the stripey disk Steve mentioned must be having the strobe effect built-in. (Like a stripey disk spinning under a stationary disk with stipey holes in it such that you need to look at the spinning stripey disk thru the holes). This would work under an incandescent lamp but would not be very accurate under a florescent lamp (because of a bit of inherent strobe effect). I am supposing this because Steve seemed very confident :-) -- WikiCheng | Talk 04:17, 12 July 2007 (UTC)

Ahh, I get it! The "effect" requires pretty much a steady light as the "built-in" observation scheme depends on it. My bad as I was stuck on the strobe effect of the external florescent light which would indeed screw-up the intended effect. Sorry :-( hydnjo talk 04:32, 12 July 2007 (UTC)

?? I'm a bit confused here. High quality turntables that were around when I was young usually had a series of white stripes around their rim - in fact, usually 3 rows, one for 33 rpm, one for 45 rpm and one for 78 rpm. I seem to remember that the machines usually had an inbuilt light source close to the stripes, and the light source was modulated, probably in synch with the mains power supply, so that the speed was right if the appropriate row of stripes appeared stationary. (The design would vary between countries with 60 Hz and 50 Hz mains supplies). Also, incandescent lights tend to show less strobe effect than fluorescent tubes because their thermal time constant is longer than the persistence of phosphors; hence some people find the flicker of fluoro tubes more distressing than the flicker of incandescent lights. I don't see how a strobe effect with one spinning disk and one stationary would work, without some time-dependent reference illumination. --Prophys 12:39, 12 July 2007 (UTC)

Right - some decks have them around the rim instead of in the center. (Come to think of it - the ones at the last radio station I worked in were like that). My own (ancient) Technics deck has them in the center which is not as convenient because you can't see it with the record on there and the stylus down. Since the stylus must add a bit of drag, calibrating the turntable with the record actually on there would presumably be the most accurate method. I haven't seen one with a light source actually mounted onto the deck - that would be handy - but incandescent room lamps work just fine - I used an angle-poise lamp at the radio station. SteveBaker 13:42, 12 July 2007 (UTC)

While we're at it, why don't the turntables just adjust the rotation speed themselves? It must have been many years since the electronics needed were too bulky to be worth it. —Bromskloss 13:52, 12 July 2007 (UTC)

Some did (with crystal oscillators or what-have-you. But folks, especially high-end audio folks, like to have things to tweak. My AR turntable simply had a synchronous motor so it was as line-locked as the stroboscope would have been.

Atlant 15:07, 12 July 2007 (UTC)

The wattage of the incandescent bulb you use will affect the degree of 60 hz modulation. I have found that 100 or 200 watt bulbs appear to take longer to reach full brightness or to dim than say 30 watt bulbs, whose filament has less thermal inertia. A neon bulb is ideal, and a normal flourescent is better than an incandescent. The powerline frequency does vary slightly, generally running slightly slower when the system is heavily loaded (like on a hot afternoon) and then slightly faster in the middle of the night to "catch up" any synchronous clocks. The frequency usually varies by only a few hundredths of a hertz, but the clock time (which is the frequency integrated) sometimes gets 30 seconds or so behind. The frequency variation should be way too slight to affect the heard pitch. It is always possible that in making the record, with the various steps of copying and editing analog tapes,or earlier wax master discs, there could be noticeable pitch variations. I learned that old time jazz musicians did not really play in the bizarre keys the records seem to be in; it was speed variation in the production of the records. In these cases, you should tune the record to concert pitch by making the record play slower or faster. Analog tapes, wax recordings, and even the cutting of master ciscs for the stamping process, were not guaranteed to be at perfect speed, since the usually were at the mercy of the powerline frequency, which probably had far greater speed variation in bygone decades. A sidenote is that DVDs of American TV programs may play 4% faster in Europe and other places with PAL TV systems, with a corresponding increase of 2/3 of a semitone in pitch, because of 25 frame/second projection there and 24 frame/second projection in the US. The film being over 4% sooner could be a "feature" rather than a defect" if the film is lousy. But PAL TV viewers will find that when they watch a film in the theater it will have 24 frame projection and the pitch will be correct. Some of the latest DVD players are able to show films on PAL systems with correct pitch. [1]Edison 16:10, 12 July 2007 (UTC)

Sorry to interrupt discussion, but Jpgordon was right- the turntable was a tad fast, and I was able to adjust it. Thanks --Sturgeonman 17:39, 12 July 2007 (UTC)

Fates worse than death in nature?

I personally have sympathy for a cockroach at the hands (mandibles?) of the emerald cockroach wasp - and the male anglerfish. So, does anyone know of any other (worse?) examples of dark, lingering, skin-crawling nastiness that the creatures of the land, sea and sky may be subjected to by cruel, cruel nature? --Kurt Shaped Box 00:53, 12 July 2007 (UTC)

Hey, I thought the male anglerfish has it pretty good - permanent female companionship and free food! Vultur 15:53, 12 July 2007 (UTC)

At the cost of his life and very existence as an individual. I *could* make a parallel to marriage here - but I'm not going to... --Kurt Shaped Box 15:59, 12 July 2007 (UTC)

I was joking, in case it wasn't obvious. Vultur 20:32, 13 July 2007 (UTC)

I wasn't. :) --Kurt Shaped Box 02:51, 15 July 2007 (UTC)

Dunno for sure but what is the seagull's favorite breakfast? ~ hydnjo talk 02:01, 12 July 2007 (UTC)

Round here, a gull's typical breakfast will include one or more of the following: kebab meat, cold chips, pizza, half-eaten burgers, Chinese/Indian food, vomit. Basically whatever the staggering drunks drop in the street on the way home after the pubs close... --Kurt Shaped Box 16:03, 12 July 2007 (UTC)

Since we don't know for sure what's the experience of death we can't really compare them can we? --antilived^{T | C | G} 02:33, 12 July 2007 (UTC)

Ahh, but there's always Imagination which was what I think Kurt was mining for (even though he asked "....does anyone know..." ). ~ hydnjo talk 02:42, 12 July 2007 (UTC)

Well, if you consider magnifying glasses natural... --L^augh! 02:53, 12 July 2007 (UTC)

Ouch! ~ hydnjo talk 03:05, 12 July 2007 (UTC)

'Ribeiroia ondatrae trematode' in its lifecycle, enters into frog's tadpole, induces the growth of additional limbs and immobilizes it so that a crane could make a meal of this frog. Since the frog could move nowhere, it starves and lays there until its death(either by starvation or by being a meal). All this is done to make sure that the trematode enters into the crane where it produces the eggs. —Preceding unsigned comment added by 220.227.179.5 (talk • contribs)

Check parasitoids, these are parasites which eventually kill their hosts after a usually long and gruesome process. Or you could have your parasite-infected pulsating eyes ripped off repeatedly by birds, like this brain-function-altered-by-parasitic-worms snail... http://www.youtube.com/watch?v=EWB_COSUXMw Sifaka ^talk 06:45, 12 July 2007 (UTC)

Omarska? Well, humans, even if inhuman, are part of nature, too. 84.160.198.39 18:46, 12 July 2007 (UTC)

I've always been partial to parasites which are able to control the host victim's brains. Dicrocoelium dendriticum, Toxoplasma gondii, gordian worm, etc. --65.112.10.129 20:09, 12 July 2007 (UTC)

WTF? How on earth does something like that evolve? That's some of the most bizarre stuff I've ever read... --Kurt Shaped Box 21:57, 12 July 2007 (UTC)

Toxoplasma is a remarkable example of exploitative co-evolution with its hosts. Recent research suggests the Toxoplasma migrate to the medial amygdala in the brain of the infected rodent. This part of the brain is involved in an innate fear response of rodents (it gets activated when mice are exposed to cat odors and display characteristic fear behaviour). These innate responses evolved in rodents because it hugely favorable to respond to predators innately, rather than having to learn to avoid cats. However, the problem with innate responses (both attractive and repulsive) is that when the signal "goes wrong" there is no mechanism for the animals to over-ride it (as there would be with associative cues). This makes it a prime target for attack.

So through a mechanism unknown, the Toxoplasma are able to alter the way the amygdala integrates the cat odors and diverts the mouse behavioural response from fear. This means the infected mouse is less likely to avoid cats and thus more likely to be eaten, which is what the Toxoplasma wants so it can complete its life cycle. Rockpocket 07:09, 13 July 2007 (UTC)

The tarantula hawk wasp is similar to the emerald cockroach wasp that Kurt mentioned. (Just saw it on the telly.) Never thought I'd feel sorry for a tarantula. --Heron 19:11, 13 July 2007 (UTC)

The tarantula hawk was featured on 'John Lydon's Megabugs'. Some toughguy volunteered to be stung on the arm by one. He dropped to the floor like he'd been poleaxed and lay there trembling and screaming. --Kurt Shaped Box 22:23, 13 July 2007 (UTC)

There are lots of poisons that can cause terrible pain. There is also suicide- something must have happened to people that kill themselves that is worse than death. And I'm not sure if it counts, but intercission is horrible too. Just because it doesn't happen in this universe, that doesn't stop it being natural. Although by nature I think the OP may actually mean non human.

Heat transition with colour

How does the colour of somthing affect how hot the water inside it is? —Preceding unsigned comment added by 210.54.194.29 (talk • contribs)

If you're asking how the color of a container of water affects the temperature of the water, this was recenctly discussed at the reference desk, and the archive is here. If this is not what you mean, you'll have to be more specific. Someguy1221 07:44, 12 July 2007 (UTC)

insulation affecting current

HI.... i wanted to do an extensive project on electricity and i thought of something. When i take a normal conduucting wire with a plastic insulation on it, and connect it in a circuit, does the insulation affect the current carrying capacity of the wire? i mean to say in one case if i apply a potential to it and suppose with the help of an ammeter find that lets say 10 amps of current is flowing through it....and in another case if i take the same conducting wire but this time without the insulation coating, will more current flow? like does the insulating material affect the current conducting capacity of the wire? i know we might get a shock if there was no insulation....but is this phenomenon possible? will more current flow? and if it will then how can i design an elaborate practical experiment...i mean for my project i need to take experimental readings and collect the numeric data....so how do i design the circuit?

This was asked a week or so ago. It is extremely complicated. However, there are many reasons why insulation reduces the current-carrying capacity of the wire for high current levels. At normal current levels, the insulation has no noticeable limitation. -- Kainaw^(what?) 12:03, 12 July 2007 (UTC)

If it is a good insulator, there will be no change in the current carrying capacity. But if the insulator is not good enough (if it is partially conducting), then insulating a conductor will effectively increase the cross sectional area of the conducting surface and hence this will reduce the resistance, thereby increasing the current. Kainaw... I am curious to know how the insulator reduces the current carrying capacity? Can you point me to any article on the wikipedia / web ? -- WikiCheng | Talk 12:18, 12 July 2007 (UTC)

I think the idea is that the insulation melts if it gets too hot and in that way puts a limit on how much current you can draw. Also, but I'd guess this is less important, since the insulation insulates the wire thermally as well, the wire gets hotter than without it. —Bromskloss 12:43, 12 July 2007 (UTC)

It also matters whether the electrical insulation also acts as thermal insulation. If it does, the copper conductor will run warmer (for a given current flow) and the conductor will change its electrical resistance. So yes, when carefully analysed, the insulation does affect the current flow in the wire even before the insulation bursts into flames.

Atlant 13:11, 12 July 2007 (UTC)

You should really check back through the archives for the full discussion - but in brief, the other point is that the insulation has additional properties in preventing cross-talk between adjacent wires where higher frequency signals are present. SteveBaker 13:22, 12 July 2007 (UTC)

I forgot that part of the previous conversation. It really matters what you plan to use this for. If it is for power, then we are discussing thermal insulation. If it is for data transfer, we are discussing electrical insulation. However, both schools of thought came to the same conclusion - the current carrying capacity (regardless of signal interference) is only affected by insulation when you are handling extremely high currents - in which case the wire heats up and becomes resistant to current. Insulation makes the wire heat up faster. -- Kainaw^(what?) 13:30, 12 July 2007 (UTC)

Brrrr

I was searching for information on different methods of Cold adaptation in plants & animals. I couldn't find exactly what I was looking for but did find articles such as Cryobiology (meaning 1), Psychrophile, Arctic_ecology#Plant_Adaptations, Cold hardening, Hibernation etc. Basically I'm not so interested in methods of keeping warm so much as ways that organisms keep alive, reproduce etc when they are cold for long periods. Maybe there's a more specific term for this that I'm unaware of? JMiall₰ 13:46, 12 July 2007 (UTC)

I just queried our library periodical catalog for "cold hibernation" and turned up two interesting articles about survival and reproduction in animals that spend long periods of time in cold hibernation. None of them are available on the web. Try checking a university library. -- Kainaw^(what?) 13:50, 12 July 2007 (UTC)

As far as I know, the principal effects of low temperature are 1) slowing down chemical reactions in general 2) the growing of ice needles that will destroy the cell membranes mechanically and 3) the change from liquid to solid state that inhibits the transport of molecules cross the cell. Additionally, many enzymes have a temperature optimum and will not work efficiently above or below. Item 1 does only affect the time scale. Item 2 is deadly but can be avoided by dehydration or by substances that lower the freezing point of water or prevent the freezing into needles. (See trehalose.) 3 without 2 need not be deadly as such but prevents any metabolism, making life impossible while in this state. 84.160.198.39 18:36, 12 July 2007 (UTC)

by "cold for long periods" do you mean organisms that have adapted to a generally cold habitat, or changes that they go through during winter, or freaky cold weather that they've never encountered before? Bendž|Ť 21:33, 12 July 2007 (UTC)

Baffling Bananas.

I had this banana and i pulled the little sticker off of it. i didn't eat it and the place where i left it was really sunny. after a few days, the whole banana was black, save for the place where the sticker had been. what would cause that place to remain normal banana colored?

Complete guess here. I would suppose most of the blackening would be caused by evaporation of water. This wouldnt be able to happen in the place where the sticker was, due to the thin film of glue that was left behind. Other processes of outgassing would also be inhibited. Bacteria would be unable to attack the glued area? I'd love to be proved wrong on this if I am wrong, though. (I'm not exactly knowledgable about food spoilage). Capuchin 14:39, 12 July 2007 (UTC)

I believe the answer lies in polyphenol oxidase, an enzyme that causes the browning of fruits. It requires oxygen to convert phenols to quinones (which turn into melanins--these have antibacterial, anti-fungal and other protective benefits for the fruit--which are dark in color). The sticker (and perhaps residual glue after removal) would have prevented the enzyme's activity. — Scientizzle 15:41, 12 July 2007 (UTC)

"If the black box is the only part of the plane that survives the crash, then why don't they make the WHOLE PLANE out of the black box?" Of interest, this patent idea would use this principle. - CHAIRBOY (☎) 16:19, 12 July 2007 (UTC)

So if they coated the entire banana with this glue stuff they'd last longer? Nah - I have an alternative theory. Perhaps the banana had gotten enough sunlight to be close to turning black - except where the sticker was. When you peeled the sticker off, the area beneath hadn't yet been exposed to sunlight - so it wasn't yet ready to turn - while the rest of the banana had already had enough sun to be close. I prefer this to the "thin layer of glue" hypothesis because the glue is likely to be pretty transparent - where the sticker was not. SteveBaker 16:22, 12 July 2007 (UTC)

So, why don't all bananas thus come covered in peelable glue-backed plastic? ;) --Kurt Shaped Box 16:26, 12 July 2007 (UTC)

The banana was indoors in a non-sunny spot before I accidentally left it out by the window, so I tend to think that it wasn't the difference in sun exposure time. Also, when I picked it up after a few days it was completely black (and mushy) except for the small Dole sticker shaped yellow patch. It was pretty cool to look at. I took a picture and hope to get that on here later.

That is to say that the side that was down on the windowsill would also be less black or not black at all if it were a matter of sun exposure.

I suspect that the stickers are applied before the ethylene gassing used to trigger ripening, and so the are of skin beneath the sticker ripens far more slowly than the rest of the banana. DuncanHill 21:33, 12 July 2007 (UTC)

You're probably right and this illustrates the point. The primary reason the bananas are ripening is because ethylene has been applied to them. That's why this this whole glue thing don't work. Sure you could apply glue to the banana and stop it receiving the etylene but the whole reason you've exposed it is so it's ripe in a few days time when the customer buys it and the customer doesn't have to wait a few weeks for it to ripen Nil Einne 20:34, 15 July 2007 (UTC)

chemistry

can any one say how many electrons are released from glycerol after oxidation???

GLYCEROL+O2(OXIDATION) ------>?????????

Please do your own homework.

Welcome to Wikipedia. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. -- Kainaw^(what?) 14:07, 12 July 2007 (UTC)

I don't believe it... there's actually a template for it... 68.39.174.238 15:24, 12 July 2007 (UTC)

It isn't used nearly as often in the summer - most summer school kids don't appear to come here asking others to do their homework (which may be why they are in summer school). -- Kainaw^(what?) 15:27, 12 July 2007 (UTC)

I agree with the above. You should try to do your own work first. But, my suggestion is to figure out what the product of that reaction is. Then you could figure out your answer based on oxidation states or hydrogens gained/lost or etc...Eclipse45 18:54, 12 July 2007 (UTC)

Is it a catalytic low temperature oxidation on an surface (heterogenus catalysis) or even better wit a soluble catalyst in oxygensaturated fluorocarbon? Or is it an high temperature oxidation ? Or is ist a very high temperature oxidation? Is it only one oxygen per molecule or are there enough for quatitavie reaction? From any oxide of carbon to a C3 suggar anything is possible. But go an ask your teacher the exact conditions for the reaction.--Stone 19:24, 12 July 2007 (UTC)

Caffiene Overdose

How much caffiene can a person of average height and weight consume before it becomes potentially harmful. I heard that if you drink three or more Monsters it can cause heart palpitations and the like.

The caffeine article has lots of information about caffeine, including toxicity. DMacks 16:43, 12 July 2007 (UTC)

To clarify; Caffeine has an LD₅₀ of about 200 mg/kg - a person who weighs 1 kg would have a 50% chance of dying after drinking 200mg of caffine; a person who weighs 85 kg (average male weight in the US) would have a 50% chance of dying from 17000 mg of caffine - thats 125 cups of coffee, 170 shots of espresso or 60 cans of Cocaine (not the drug!). Of course, poisoning is all about chance; people have died from as little as 2 grams (that's about 15 cups of coffee), and some have survived massive caffeine intake. Monster don't seem to give a precise quantity of caffeine for their drinks (they lump it in with all the other stimulants, but I'd guess that it has a similar caffeine content to the "cocaine" drink. Laïka 18:57, 12 July 2007 (UTC)

It should be noted that the threshold for harm, and just plain feeling awful, is potentially considerably lower than the amount that can kill. If you are looking advice regarding your personal usage of caffeinated beverages, please consult your physician. Dragons flight 19:03, 12 July 2007 (UTC)

Yes - the LD50 level only tells you that 50% of people will die from it. It doesn't say anything about what dosage will make you suffer from the symptoms of a milder Caffein#Overuse...you can suffer an awful lot of injuries before you actually die! SteveBaker 22:32, 12 July 2007 (UTC)

60 cans of Cocaine at 240ml per can is 14.4 litres. Even if one had a super-Kobayashi-like capacity to expand one's stomach to accomodate such a megaload, you'd be dead from hyponatremia/water intoxication before the caffeine got you (that 14.4 litres is nearly double the volume that killed Jennifer Strange). -- Finlay McWalter | Talk 22:54, 13 July 2007 (UTC)

It's important to point out that saying a person who drinks consumes 200 mg has a 50% chance of dying due to caffeine toxicity is IMHO somewhat inaccurate. A person who consumes this much caffeine may very well have a 100% chance of dying. However 50% percent of people who consume this much caffeine will die. Of course, this LD₅₀ is only an estimated one, since no one actually determined LD₅₀s in humans nowadays. Nil Einne 20:27, 15 July 2007 (UTC)

I prefer to believe the Futurama episode Three Hundred Big Boys when examining, for example, the effect of one hundred cups of coffee on a human, and I quote, "As the flames spread rapidly through the room, an agitated Fry, shaking violently from his massive caffeine intake, heads for the buffet table and drinks his hundredth cup of coffee. Fry enters a caffeine-induced state of hyperspeed, then rescues everyone at incredible speed and puts out the fire.". Fry is unharmed and shows coffee to be an excellent method of achieving hyperspeed. Lanfear's Bane

A kind of intelligent design

Still thinking about Gliese 581 c and what planets like that could be, I wonder if anyone has thought about what an intelligent design for life on such a planet could look like. By intelligent design I mean a state consistent with what we know about the way the universe works (in other words, chemistry and physics) but which does not necessarily need any likely evolution process in which it could have evolved 'from scratch'. 84.160.198.39 19:01, 12 July 2007 (UTC)

Well since almost nothing is known concretely about the conditions on Gliese 581 c I'm not sure what one would speculate about. And if you are opening up the possibility of alien/deity created forms then there are not any reasonable limits to speculation. So I'm not exactly sure what you are asking about. --65.112.10.129 19:55, 12 July 2007 (UTC)

As a base, Gliese 581 c is a planet about the size of earth, even heavier, so it can hold an atmosphere where even hydrogen is not easily blown away. It orbits a red dwarf star very closely and is thus probably tidally locked to its star. It is possible, though unknown, that the atmosphere is thick enough to distribute the heat of the day side efficiently to the night side so that it won't freeze out completely, thus maintaining the pressure necessary for liquids. Maybe Gliese 581 c itself, if with an atmosphere, is too hot for liquid water. Maybe it could (by intelligent design????) have rings like saturn to shade it. Maybe the light of the star has a too large wave length to be put to use for chemical reactions (photosynthesis), but maybe the heat on the day side is enough to imbalance the chemistry of the atmosphere enough that energetically rich molecules (carbon monoxide?), driven by storms, could nourish alien life on the night side? What I have described here are pure speculations of mine, what I'm looking for is if anyone has done similar speculations, but on a scientific base, like, say, done some calculations about the energy that could be trapped on the day side by dissociating carbon dioxide to carbon monoxide and how fast the winds would have to be to transport that energy source to a region cool enough to keep proteins, as we know them, stable. 84.160.198.39 20:39, 12 July 2007 (UTC)

The concept of considering intelligent design here or in other planets is hardly scientific. What evidence do you have to even begin to assume that inhabitable extrasolar planets would have to be created in "just right" conditions? So far most planets we've found are totally uninhabitable hot Jupiters, as far as we can expect life, so it strikes me as odd that a random smaller planet that seems to be "better" than the others would be "made that way" by an intelligent thing. Chance alone would account for that sort of thing, no need for an intelligent designer. Besides, you seem to be more interested on scientific analysis of current data and speculation on it about probabilities of life and etc. There's probably something like that around by now, but our speculations can't go very far since we only have Earth's life as a sample. — Kieff | Talk 07:00, 13 July 2007 (UTC)

If we find 200 exoplanets, and 199 are places where life anything like our carbon based lifeforms are inconceivable, then one is found where life is not so implausible, then one can point to it and say "Look! Evidence of intelligent design!God made a perfect planet because he loves the 'Gliese 581 c'ians" while ignoring the 99.5% of exoplanets where life is impossible. In the same way the Anthropic principle suggests that a vast, almost limitless array of universes could arise through random processes, and only in the one where matter exists and can combine to form stable carbon compounds, and where there is a planet with appropriate temperatures, continents, water, oxygen, etc. are there life forms to say "What a miracle! God made us a perfect planet because He loves us." There would of course be no one similar to us swimming around in a universe where everything was such that there were no planets, or no stars, and observing that God must hate them. Edison 15:25, 13 July 2007 (UTC)

The Anthropic Principle is the natural extension of cogito ergo sum to the entire universe. Nimur 15:34, 13 July 2007 (UTC)

Hydrogen Peroxide and Saline Solution/Clothing Stains

How is hydrogen peroxide 3% neutralized (such as in a contact lens case, there's a gray disk on the bottom of the lens basket, which makes the lens cleaner bubble and froth), resulting in "unpreserved" saline? What is "unpreserved" saline? How does "unpreserved" saline stain clothing? - MSTCrow 21:22, 12 July 2007 (UTC)

Well, I think your hydrogen peroxide is: "Hydrogen Peroxide 3%...Neutralised" and not "Hydrogen Peroxide...3% Neutralised"...if you see what I mean. 3% means that you have 97% water and 3% hydrogen peroxide which is a pretty standard solution for domestic use. Strong peroxide solutions are really nasty to handle - so you can only buy the dilute stuff over-the-counter. I believe peroxide is somewhat acidic - so probably they added some alkali to the solution to get the pH back to neutral. "Unpreserved saline"...I have no clue. SteveBaker 22:24, 12 July 2007 (UTC)

I'm pretty sure I don't understand your question, but I'm going to try anyway... Saline solutions usually have preservatives -- like Thimerisol to prevent infection. Peroxide-based lens cleaners don't need preservatives, because the hydrogen peroxide is an effective preservative. However, left to itself hydrogen peroxide will decompose to water and oxygen gas. The little gray disk accelerates this decomposition. Once all the hydrogen peroxide has decomposed, you are left with just a saline solution that now is no longer preserved.

Unpreserved saline shouldn't be able to stain clothing, being little more than salt and water. However, if the HP is still active, it acts as a bleach. HP is found in some color-safe bleaches and in many over-the-counter tooth whitening pastes. --Mdwyer 00:51, 13 July 2007 (UTC)

I'm pretty sure that's what's going on, thanks. Although I wonder what the gray disc is, and why they told me saline water could still stain clothing. - MSTCrow 01:49, 13 July 2007 (UTC)

Lots of things catalyze the decomposition of hydrogen peroxide into water and oxygen, and if this reaction is fast enough, one can observe the oxygen bubbles. Perhaps the disk is manganese dioxide or some other catalyst for this reaction? DMacks 04:36, 13 July 2007 (UTC)

Help yourself to some hydrogen peroxide and saline solution links. StuRat 15:23, 15 July 2007 (UTC)

Black holes, neutron stars and the Habitable zone?

Can the Habitable zone concept be applied to planets in orbit around black holes and neutron stars? --Kurt Shaped Box 22:46, 12 July 2007 (UTC)

Seems that way. Since there is a black hole at the center of many galaxies, the galactic habitable zone relates to the location of the planet vis-a-vis the black hole. Shalom ^Hello 22:54, 12 July 2007 (UTC)

Except for the fact that without a heat source of sufficient magnitude then it isn't really habitable. If you are only talking about it in terms of distance, then sure, but if you do that then you are ignoring a major part of what makes the distance relevant (conditions for life). Neither neutron stars nor black holes radiate enough energy themselves to be relevant here; if you imagine them having some sort of accretion disk, then maybe, but I'm not sure if that energy would translate into wavelengths favorable for life (if it is all in the X-ray, then that's not going to help anybody). -24.147.86.187 23:02, 12 July 2007 (UTC)

It certainly wouldn't help *us* or any of the critters we share a biological domain with - but why could it not be the case that there is life 'out there' that thrives on hard x-rays? Man, I love these exobiology topics... ;) --Kurt Shaped Box 23:07, 12 July 2007 (UTC)

Sure, but that's a bit outside the definition of "habitable zone", which defines "habitable" based on life as-we-know-it on Earth. --24.147.86.187 01:26, 13 July 2007 (UTC)

• slaps head* I knew that. Really. :) --Kurt Shaped Box 01:44, 13 July 2007 (UTC)

The Habitable zone is also based on our current techonology. I could take a planet in the middle of nowhere with enough hydrogren and a nuclear fusion reactor and make it habitable if I could contain an atmosphere and can put it into orbit around a star :). In any case, if wikipedia becomes a black hole, what will we do? Can we safely revolve around it?--GTPoompt(talk) 13:02, 13 July 2007 (UTC)