Wikipedia:Reference desk/Archives/Science/2009 February 15
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February 15
[edit]How do I genetically engineer the world's best sports team?
[edit]I was thinking thru cloning. Like chip some skin off our top baseball and football players and thier offspring's genetic code would be the same, right? So they would have an excellent chance of being athletic in a superior way, I take it? Then in about 20 years,-"And now,- presenting the only 162-0 baseball team in history,-". They would then take the field proudly and win another 27-0 shutout. Is this dream possible?Baseball and and and Popcorn Fanatic (talk) 00:17, 15 February 2009 (UTC)
- How do you genetically engineer the world's best sports team? You begin by getting a degree in genetic engineering and hope that by the time cloning techniques are advanced enough to allow such a thing, that it is legal to do so in whatever country you plan on cloning your humans. In addition, you also need to make sure that for whatever sport you plan on having your players compete in, that cloned humans aren't banned similar to doping. There's also the question of whether your human clones will actually want to play for you and not other teams. Finally, if you plan on having your players compete in a professional league, you may find it useful to buy a franchise. But be forewarned that such franchises are cost-prohibitive. The Chicago Cubs, for example, are currently being sold for $900 million. A Quest For Knowledge (talk) 01:18, 15 February 2009 (UTC)
- You may also wish to consider what makes you enjoy watching your team win. Is it the elegance of each batter's swing and the movements of the catchers (sort of like ballet?) or is it the uncertainty of the outcome of the game? A majority of spectators would abandon the game if your team so far outperforms other teams that the outcome is a given. So your franchise would go broke and your perfect players would have to go work in jobs they weren't engineered for. 76.97.245.5 (talk) 02:04, 15 February 2009 (UTC)
Your clone breeding project comprises a violation of Equal opportunity that not even eugenicists contemplate, and which would raise issues of medical ethics and legality in athleticsCuddlyable3 (talk) 18:17, 15 February 2009 (UTC)
speeding up human gestitation
[edit]is there any way to speed up the 9 months? how about in non-humans? —Preceding unsigned comment added by 82.120.236.246 (talk) 00:52, 15 February 2009 (UTC)
- It seems very unlikely. Any effort to mess around with the cell division rates would likely screw up the development in one way or another. Perhaps you could do it in VERY primitive organisms - but not in 'higher animals'. SteveBaker (talk) 01:44, 15 February 2009 (UTC)
- That's only if you want the newborn to be normally developed, of course. It's easy enough to induce birth early if you don't mind an underdeveloped baby. Algebraist 02:53, 15 February 2009 (UTC)
- You could always have nine women work on one baby, they should be able to get it done in about a month.--OMCV (talk) 02:56, 15 February 2009 (UTC)
- You, sir, should work in management. You would go far. -- Captain Disdain (talk) 09:06, 15 February 2009 (UTC)
- You could always have nine women work on one baby, they should be able to get it done in about a month.--OMCV (talk) 02:56, 15 February 2009 (UTC)
- That's only if you want the newborn to be normally developed, of course. It's easy enough to induce birth early if you don't mind an underdeveloped baby. Algebraist 02:53, 15 February 2009 (UTC)
- As far as non-humans go, in viviparous reptiles it is possible to reduce the gestation length by increasing the ambient temperature, up to some point. For mammals, esp. placental mammals - I doubt it. --Dr Dima (talk) 04:18, 15 February 2009 (UTC)
- Travel in a spaceship and come back. You will notice time dilation. But don't go too far or too fast or you'll miss a birthday or few.Cuddlyable3 (talk) 17:51, 15 February 2009 (UTC)
- Most non-humans already gestate in fewer or more than 9 months, presumably for their own good reasons. Cuddlyable3 (talk) 17:54, 15 February 2009 (UTC)
- An unfortunately serious answer follows. By definition, a human baby that is born early is a preterm birth and will probably suffer from a large number of mild to serious medical complications, mostly relating to underdeveloped systems. Low birth weight is already a problem, and accelerating the birth to an even younger gestational age would severely increase the numerous accompanying conditions, infant mortality, and long-term problems like cerebral palsy, mental retardation, and other developmental disorders. Speeding up a human birth would have serious medical ramifications. Nimur (talk) 16:37, 16 February 2009 (UTC)
Yellow Sodium Light
[edit]Hello. Why is yellow sodium light the reference point in determining refractive indices? Thanks in advance. --Mayfare (talk) 05:13, 15 February 2009 (UTC)
- Until an expert comes along, all you'll have is an educated guess. Yellow is kinda in the middle of the optical spectrum, the sodium output is very bright and unambiguous, and a yellow sodium light emitter should be readily available to any researcher (if nothing else, salt sprinkled in a Bunsen burner flame). Bunthorne (talk) 05:46, 15 February 2009 (UTC)
- Sodium has a bit of info on the history. Also see Fraunhofer lines 76.97.245.5 (talk) 06:04, 15 February 2009 (UTC)
- (EC) note by unambigious a key point may be it's fairly monochromatic Nil Einne (talk) 06:09, 15 February 2009 (UTC)
- Indeed, the key point is that it emits light at one very specific and precisely known frequency. --Tango (talk) 12:39, 15 February 2009 (UTC)
- (EC) note by unambigious a key point may be it's fairly monochromatic Nil Einne (talk) 06:09, 15 February 2009 (UTC)
- Think about white light (eg sunlight). If you shine white light through a narrow slit and into a triangular slab of glass (a 'prism') it spreads out into a broad rainbow-like spectrum. It's hopeless to try to measure the angle the light was bent by because each of the colours got bent by a different amount. When you measure refractive indices, you are measuring that angle - and you get a different answer for different frequencies of light - so if you want to express it as a single number, you need a very pure light source. Sodium emits an almost pure yellow light - there are actually two frequencies but they are very close together. When you shine sodium light through a slit and into a prism, it doesn't split up - you get just two bright yellow lines (which are very close together) instead of a rainbow. It's easy then to measure the angle between the incoming and outgoing light and calculate a simple refractive index. If you used white light, you'd have to guesstimate (say) the middle of the fuzzy red/orange/yellow/green area and that would produce hopelessly inaccurate results. SteveBaker (talk) 15:25, 15 February 2009 (UTC)
- For those who are interested, our article on sodium vapor lamps has a pretty picture of the low-pressure sodium emission spectrum. Check out the article or jump directly to the image: File:Low-pressure sodium lamp 700-350nm.jpg. (The image has been somewhat overexposed to make the other emission lines visible; this also causes the sodium D line to 'bloom' out a bit.) TenOfAllTrades(talk) 16:59, 15 February 2009 (UTC)
science/geology---tides!!!
[edit]If moon's attraction causes tides during nighttime,,, but why they not occur during daytime,, even if moon is present at that time? —Preceding unsigned comment added by Nilesh raj (talk • contribs) 06:39, 15 February 2009 (UTC)
- Who says they don't? See the graph or the daytime pictures of the Bay of Fundy in the Tide article. Also, surfers don't go out only at night. Clarityfiend (talk) 07:35, 15 February 2009 (UTC)
- There are definitely tides during the day. You usually get one high tide about every 12 hours (it's not exactly 12 hours since the Moon is orbiting as well as the Earth rotating - that's what causes the tides to be at different times each day). --Tango (talk) 15:11, 15 February 2009 (UTC)
Oh cool! I can use the word! Can I say 'syzygy'? Can I please? ... Oh good - thanks!
The tide is at it's highest when there is a syzygy - which is when the sun, moon and earth are all in a straight line. That happens during the day and during the night when there is either a total solar eclipse or a total lunar eclipse.
SteveBaker (talk) 18:40, 15 February 2009 (UTC)
- How long have you been waiting to use that word? I think that was rather a stretch - the OP didn't ask about the maximum tides, just tides in general. --Tango (talk) 18:56, 15 February 2009 (UTC)
- I was pointing out that not only do tides occur during the day - but the highest tides happen at midday during a...a...well, I'm just not going to say it now...you've taken ALL of the fun out of it. SteveBaker (talk)
- Don't worry, Steve. He's just jealous because he didn't get to say 'syzygy'. — DanielLC 21:05, 15 February 2009 (UTC)
- Lies, lies! --Tango (talk) 21:29, 15 February 2009 (UTC)
- Oh, stop being such a syzy (gy whiz). Clarityfiend (talk) 02:00, 16 February 2009 (UTC)
- Lies, lies! --Tango (talk) 21:29, 15 February 2009 (UTC)
- At least you got to say it. I'm still waiting for my chance with Gegenschein. Algebraist 21:43, 15 February 2009 (UTC)
- Don't worry, Steve. He's just jealous because he didn't get to say 'syzygy'. — DanielLC 21:05, 15 February 2009 (UTC)
ENGINEER'S HELP NEEDED
[edit]HI FRIENDS
I AM RESIDING ON GROUND FLOOR OF A 3 STOREY APARTMENT.
THE PERSON RESIDING ON 1ST FLOOR ABOVE MY HOUSE HAS GOT HIS BATHROOM LEAKING IN MY HOUSE.
I TRIED HARD TO PURSUE HIM BUT HE IS NOT WILLING TO MAKE REPAIRS & ALSO IS NOT ALLOWING ME TO DO SO.
WHAT SHGOULD I DO?
I HAVE HEARD OF CHEMICALS(FOSROC HYDROPROOF)WHICH CAN HELP IN THIS BUT DONT KNOW MUCH.
ALL THAT CAN I DO IS TO MAKE REPAIRS FROM MY HOUSE ONLY, THAT IS, FROM THE BOTTOM ONLY.
IS THIS POSSIBLE?
PLEASE SUGGEST. —Preceding unsigned comment added by Saurabh85 (talk • contribs) 10:31, 15 February 2009 (UTC)
PS: On the user page of user:Milkbrath the OP mentions that he ad his / she and her neighbour are owners the apartments. --Cookatoo.ergo.ZooM (talk) 16:04, 15 February 2009 (UTC)
- First of all, I suggest you turn off your caps lock key.
- Secondly, to begin with, I suggest you contact the owner (or owners) of the building, or the building's manager, or some comparable party. Water damage can get very expensive if the problem isn't addressed, and it's likely to affect a lot of people other than just the people who live in the apartments in question. You don't mention whether you own the apartment or are renting; if you're renting, contact your landlord. The Wikipedia Ref Desk is probably not a good place to get help with this; you really should notify the building's owner or owner's.
- Thirdly, I very much doubt that any chemical could fix this problem. I guess it might keep the water from your apartment, but it's not going to make the water go away: it's still going to be up there, leaking and doing damage. It will rot wood, rust steel, cause molds to grow, etc. You really need to move on this now; the longer you leave this, the more damage there will be. The leak needs to be fixed.
- Fourthly, your neighbor is not only an asshole, but -- depending on where you leave -- probably also in a bad position legally; if he's aware of the problem but refuses to do anything about it, he's probably going to end up with a pretty hefty bill. We don't do legal advice, but let me put it this way: it's probably not a good idea for you to be aware of it and not report it to anyone, either. -- Captain Disdain (talk) 11:32, 15 February 2009 (UTC)
- You state that you both are the owners of your respective apartments. As such, there must be an occasional meeting of owners to agree on communal matters where this problem should be discussed. Alternatively, as CD points out, there must be an appointed manager who looks after groundkeeping / general repairs / lift maintenance / etc.
- You may also consider to call a plumber to determine the cause of the problem and to have an expert witness at hand. If nothing else helps, take a few photos of the damp patches / dripping water / mould / whatever and contact a lawyer. Finally, you may consider the benefits of having an apartment with an indoor swimming pool. --Cookatoo.ergo.ZooM (talk) 12:04, 15 February 2009 (UTC)
- You don't need an engineer's help. You need legal help. Dmcq (talk) 12:06, 15 February 2009 (UTC)
- Maybe it'll help you if you do a little experiment to visualize your problem. You'll need 2 or 3 slices of bread. Spread a good layer of butter or margarine on two of them. Turn your faucet to a slow drip and hold the piece of bread without any spread underneath. The bread will get soaked and sooner or later water will drip from the bottom. That's your ceiling now. Next turn one of the buttered slices upside down so that the side with the spread on it faces away from the faucet. Hold that one under the faucet. That's what you'd get if you tried to seal your ceiling from below. Not satisfactory, is it? The only way to solve your problem is to stop the leak or seal the ceiling from the top. (i.e. your neighbor's floor). If there still was a leak in his bathroom (e.g. from a leaky gasket or runoff from a shower curtain) the water would then collect on his floor and he could mop it up. That is the idea behind the products you read about. They are intended to prevent the water from leaking into the ceiling. Once it's in there it will have to go somewhere. If you'd block the ceiling it would just run into your walls into your closets and under your flooring and damage those, too. It's not that we wouldn't want to help you, it's just that sealing your ceiling from the bottom isn't an idea that would work. Don't know where you are, so I can't tell you what's available in your area. You may qualify for free legal assistance from some organization. Check your condo contract and your insurance policy and follow the advice the others have given. OR We have an occasional leak in our basement and are now into our third expert trying to find and remedy the cause. This kind of thing isn't a job for DIY even if you had better skills and knowledge than you seem to have. 76.97.245.5 (talk) 14:07, 15 February 2009 (UTC)
- You don't say where you are from - and you don't say whether you and your neighbour own the apartments or are renting them - so it's hard to guess what legal options might be open to you. For sure there is no technical/engineering solution. That water is landing on your ceiling and that's that. If your ceiling is showing damage - and presuming you have insurance on your apartment - then I would make a claim on your insurance for the damage. They will come and investigate - they'll realise that your neighbour is at fault and will make a claim on him. Then there will be action. If you are renting the apartment - then you need to talk to your landlord. Whatever you do - you need to do it soon because your ceiling will collapse...and you'll also be getting mold growing up there which could have serious effects on your health. You should also talk again to your neighbour - explain clearly that if he doesn't fix the leak - and quickly - he will be responsible for all of the damage AND the leak will have to be fixed. If he fixes the leak now - then he's saving himself money. You might also check whether there is a home-owners' association for your apartment block - they would be able to help you too. SteveBaker (talk) 15:16, 15 February 2009 (UTC)
- One comment: Just because there is water leaking from your ceiling doesn't necessarily mean it's coming from the apartment directly above yours. Water can leak from another apartment or even a roof ice dam, travel down the walls until it reaches a barrier, then travel between the upstairs floor and your ceiling until it finds a spot to leak through. StuRat (talk) 17:20, 15 February 2009 (UTC)
THere's some excellent advice above. In your situation I would I would contact your building insurer immediately in the form of a letter, marked Urgent, that states that you observed a water leak start, you believe it originates from Floor #1 and that you have informed (by a copy of the letter) the resident of the danger of damage. The logic here is that if damage and argument do arise, you have proof that you took steps to limit damage, and there is no accusation that provokes the other resident. Good luck. Cuddlyable3 (talk) 17:37, 15 February 2009 (UTC)
Is there any Green Agency at India
[edit]There are agencies that help corporates move towards achieving energy efficiency like 1 degree in Australia that helps News Corp. to reduce green house gas emition.
Is their any such service at India? or other parts world wide? —Preceding unsigned comment added by 117.196.164.211 (talk) 16:24, 15 February 2009 (UTC)
- This might be a start [1].76.97.245.5 (talk) 23:59, 15 February 2009 (UTC)
Past weather data
[edit]Please, is there an internet source for detailed past weather data? I'm looking for specifics (e.g., weather in Wales on a specific date), not long-term weather records. I realize that what I am looking for would require a large database.
Thank you, Wanderer57 (talk) 16:39, 15 February 2009 (UTC)
- Try searching newspaper sites. If they've got their archives online, just pick the date you're interested in. B00P (talk) 17:26, 15 February 2009 (UTC)
TuTiempo. I found it a couple of months ago looking for historical weather data for Cape Town. The site is amazing, it has daily weather data for seemingly every city in the world going back decades, and not just temperatures, it has precipitation and cloud cover and everything. Knock yourself out! Zunaid 17:51, 15 February 2009 (UTC)
- p.s. you have to click on the "climate" section in the left-hand column. The link for the UK is this. Zunaid 18:45, 15 February 2009 (UTC)
- In the U.S. Weather Underground is very similar. I don't know what its like for locations outside the U.S. however. --Jayron32.talk.contribs 18:35, 15 February 2009 (UTC)
- For locations (airports) in Canada, The Weather Network has historical weather data for most dates in the current millenium. ~AH1(TCU) 16:41, 16 February 2009 (UTC)
- The National Weather Service provides recent and current archives, and also has an FTP server with long-term archives, for all US locations and many many world-wide locations. They are a little "more official" than WeatherUnderground, but their database requires a bit more technical savvy to access. Nimur (talk) 16:45, 16 February 2009 (UTC)
For specialist only...!
[edit]I'am working at construction feild , as asite engineer
now we're filling the spaces between the foundation according to cast the (slab on grade ) , to save time we are using single size aggregate instead of selected natural material , now and according to the plans there is a 15 cm layer of basecoarse under the slab , the question is this ...?
if i execute this layer , and we assume some how water did find its way to this layer , dont you think that the water will carry the fine material contained in basecoarse and move it down ward through the voids between single size agg. particles ,leading to deflection in the slab.
and , is the only purpous of (15 cm layer ) of single size to protect the slab concrete from being in contact with the natural fill material , and why ...?
i know its hard to understand all of this but i hope to get an answer ... ? —Preceding unsigned comment added by 94.249.40.92 (talk) 17:34, 15 February 2009 (UTC)
- This is, essentially, a legal question. At least, it is a question which requires knowledge of building regulations in Jordania, knowledge of the plan of the building, the specifics and substrate of the buidling site, the reinforcement of the slab, the aggregate you are using for the fill, data on precipitation / groundwater and a few details more. I can´t imagine that you will get useful answers from a distance, even from static engineers. --Cookatoo.ergo.ZooM (talk) 18:34, 15 February 2009 (UTC)
we are using BS standards , we dont have our own i thought its going to be the same detailes for concrete structures assume , ordinary building use , low water table , warm claimate , crushed stone fill ( course aggregate used in concrete casting ). you will find a very excellent answers at www.contractortalk.com . thanks —Preceding unsigned comment added by 94.249.40.92 (talk) 18:51, 15 February 2009 (UTC)
- Do British standards contain a section on earthquake engineering or earthquake construction? I hope we aren't going to get any more of those reports like 1999 İzmit earthquake on bad construction. Cheaper isn't always better. 76.97.245.5 (talk) 07:59, 16 February 2009 (UTC)
is it a coincedence too
[edit]I want you to follow this link , after you watch the video , please i need your objective opinion ...http:/www.metacafe.com/watch/98111/miracles_of_the_quran_12/
be objective .... thanks . —Preceding unsigned comment added by 94.249.40.92 (talk) 18:41, 15 February 2009 (UTC)
- Many of us do not go to off-WP sites that could be anything. You can help us help you by asking your question, please, and by telling us what the link purports to show. We prefer to deal with facts, not opinions, objective or otherwise. Thanks ៛ BL ៛ (talk) 18:47, 15 February 2009 (UTC)
- That's not a coincidence, it's just nothing at all. So the Qur'an mentions the tips of the fingers, who cares? I'm sure people noticed that fingers had tips long before the Qur'an was written. It's just a reference to putting together the whole body, it makes no reference to using fingerprints for identification, or even a mention of fingerprints at all. --Tango (talk) 18:53, 15 February 2009 (UTC)
will ... this link will show avideo talking about finger print and that quraan referred to it and that each person do have a unique finger print from evry one else ... will how do they knew that ... ? —Preceding unsigned comment added by 94.249.40.92 (talk) 18:56, 15 February 2009 (UTC)
- The quote from the Qur'an doesn't mention uniqueness at all. It doesn't even mention fingerprints, just the tips of the fingers. --Tango (talk) 19:03, 15 February 2009 (UTC)
- And even if it did, the observation that fingerprints are unique is something that anyone who looked at them would be able to figure out. It doesn't require any scientific theory to understand this, so I see no reason why this couldn't be known, even to prehistoric people.. StuRat (talk) 19:46, 15 February 2009 (UTC)
- Well, it's of note that it took quite a bit of time before this was really proven to be true. They look superficially similar to one another—you have to really look at them closely to see that they are in many ways very different from one another, and you have to extrapolate a bit further beyond that to think that such is a meaningful observation (why does it matter that fingerprints are unique, vs., say, noses, which are also unique). The modern significance of fingerprints for forensic criminology was not surprisingly only figured out in the 19th century or so—it requires a concept of forensic criminology first. --98.217.14.211 (talk) 20:29, 15 February 2009 (UTC)
- Yeah - this is nuts. The whole thing is based upon one line - whose English translation is: "Yes, We are able to put together in perfect order the very tips of his fingers.". This doesn't say - or even imply that "everyone's fingerprints are unique" - it says that fingertips are "in perfect order" - which I would more likely assume to mean that all fingertips are perfectly smooth - or they all have nice regular 'ordered' stripes or concentric circles or something. Fingertip patterns are a result of 'chaos theory' - which is about as mathematically 'unperfect' as you can get. So FAR from assuming that this book says that we all have unique fingerprints, I'd go so far as to say that the existance of totally different fingerprints is yet another thing proving the Quran is wrong (and lest I appear to have a western bias here - let me also point out that the christian Bible and the Tanakh and the Sefer Torah are also filled with just as much nonsense and untruths). Besides - there are many other aspects of humans that are just as unique as fingerprints. Our toeprints are also different. Our retinal patterns are different...pick the ratios of the sizes of any few dozen physical features, round them off to the nearest 1% and you'll have a number that's unique to every human on earth. There are any number of other things that are unique. Why does the Quran not mention that chimpanzees also have unique fingerprints too? Dogs have unique nose-prints. The only reason people find human fingerprints in any way 'notable' is because we leave behind little greasy patterns when we touch things with our hands - and that provides a means to tie a criminal to some place or object. I guess the Quran failed to mention that too. Furthermore - fingerprints were used as identification by the Babylonians around 4,000 years ago. Since the Quran is supposedly only about ~1400 years old - this hardly constitutes a prediction! I'm sorry - but when religious nuts of all kinds come to the science desk in an effort to impress us - they are going to get torn to shreds by actual FACTS. This is no different. SteveBaker (talk) 19:58, 15 February 2009 (UTC)
- See Fingerprint#History_and_validity for some very old uses of fingerprints. — DanielLC 20:55, 15 February 2009 (UTC)
- See, this is what irks me about people's misunderstanding of science. You can blindfold a man and ask him to throw darts at a dartboard. Every once in a while, he will hit a bullseye. Merely because he does so does not make him a good dart player. Darts is a game which requires a certain set of skills and talents and needs practice to play right, and merely because dumb luck resulted in a blindfolded man hitting a bullseye does not mean that being blindfolded and throwing random darts is a valid way to win the game. Likewise, science is a process and not a collection of facts. Just because someone randomly makes a statement, without going through the scientific process, which happens to match what rigorous scientific study has shown to be true; does not mean they got it right, and more than we can say that playing blindfolded is the "right" way to play darts. --Jayron32.talk.contribs 21:01, 15 February 2009 (UTC)
- I kind of doubt that you're interested in our "objective opinion". Essentially, you keep on coming at us with various "amazing" things from the Qur'an -- the development of the fetus, fingerprints, all of that -- and we keep explaining to you why it doesn't mean that the Qur'an is the best science book you could possibly have. It's not hard to identify you, even though your IP address changes, because... you have a very distinctive... style of writing. You keep presenting these things from the Qur'an to us, as if they were proof of something, when, in fact, all you do is either demonstrate your own ignorance (at worst) or misconceptions (at best) of science and history, or misrepresent what the Qar'an actually says.
- The ridiculous thing is, you keep doing it, and let me predict something here: if you manage to get one right and come up with an example of the Qur'an coming up with some great scientific discovery, then you'll probably hold that up as some kind of proof. That's a case of counting the hits and ignoring the misses, and frankly, I find it a little sad that you're trying to use the Ref Desk as a tool in this campaign of validation. -- Captain Disdain (talk) 21:46, 15 February 2009 (UTC)
- That is harsh and I would grant some WP:AGF to the questioner who I think honestly needed objective input. Cuddlyable3 (talk) 22:11, 15 February 2009 (UTC)
- If you read the original poster's comments -- including the one below directly below -- and believe that he has no agenda, okay, that's fine with me. I disagree, and I think his own comments back me up. But please understand that I'm not really assuming bad faith as such, either. I'm not saying he's dishonest here, because that implies some kind of a malevolence... but I don't think he really wants objective opinions or knowledge. I think he wants to present us with something that proves his faith, and that doesn't really go well together with being objective. I can understand why he does that, but the end result is that we jump through hoops. And I wouldn't mind that as such, but when he ignores what he's told and keeps hoping for that hit, it's not a very fair setup -- if he was trying to understand or looking for knowledge, that'd be one thing, but he isn't. He's looking for validation.
- I think WP:AGF is a kind of a problematic guideline a lot of the time. It's great when you run across something that makes you angry or looks weird or suspicious for the first time, but it often gets twisted into a free pass. -- Captain Disdain (talk) 08:05, 16 February 2009 (UTC)
iam not trying to press my opinions , its afact its your choise not to belive . when i talked about univers expanding ,some said it was acoincedence , and talking about finger prints some talked about darts game , and steve say it was used 4000 years ago (prove it , put some links at least ). the statment was that god will recreat us that he will even rebuild our finger tips , because they didnt have the term finger print back then , if he say finger print they are'nt going to understand , because simply they didnt have that word . i do have more , alot more and if you can make me belive this all just luck or wrong i will become atheist . and if you say it was used 4000 years ago (please prove it ). about the different addresses , will i use alot of computers ,its not even mine . have faith people ,even if thier's a probabilty about 1/1000000 that your wrong it does worth it,dosent it i dont understand why you are so angry , you should be more tolerance . excuse my english , iam not an english native ,thank you any way ... —Preceding unsigned comment added by 94.249.40.92 (talk) 22:30, 15 February 2009 (UTC)
- You seem to be referencing Pascal's wager, a seriously flawed argument. The expanding universe thing was an intentional mistranslation and the fingerprint thing is just reading more into a quote than is actually there. These aren't coincidences, they're just very poor attempts at making it look like the Qur'an is saying things it isn't. --Tango (talk) 22:36, 15 February 2009 (UTC)
- You requested a link in respect of the use of fingerprints in antiquity. See Fingerprint#History_of_fingerprinting_for_identification for statements, with sources, about the use of fingerprints as identification on legal documents as early as 1900 BCE, which is just shy of 4000 years ago. ៛ BL ៛ (talk) 22:44, 15 February 2009 (UTC)
we are using a very advanced technology to identify finger prints , and some time we have errors and your telling me that 4000 years ago they were using it to the same purpose . will .. is this make any sense , mabey they notice the shape,mabey they assume that its unique , but use it to identify people in thieft cases ... iam sorry this is too mush ...??????????? —Preceding unsigned comment added by 94.249.40.92 (talk) 23:03, 15 February 2009 (UTC)
- We use ink and some kind of powder - not very advanced, really. You don't need computer analysis for fingerprints to be useful, it just makes it quicker and more accurate. --Tango (talk) 23:10, 15 February 2009 (UTC)
- I noted that fingerprints were being used for identification instead of signatures. I said nothing about criminal use. Muslim tradition dates the Koran from around 610-630 CE. From the article "Fingerprint" linked above comes: In China around 300 C.E. handprints were used as evidence in a trial for theft. From the remainder of that paragraph, it appears that at least one other culture knew about fingerprints at the time the Koran was compiled, and this knowledge was a part of the Chinese criminal-justice system some 300 years prior to the dates of the Koran. It is fact. ៛ BL ៛ (talk) 23:23, 15 February 2009 (UTC)
- I apologize for leaving off the link - but (as others have pointed out) it's right there in our Fingerprint article. Fingerprint#History_and_validity to be precise. It says (with LOTS of impeccable references) that the Babylonians were fully aware of the uniqueness of fingerprints around 4,000 years ago. The didn't use ink - they used soft clay which was then baked into pottery to make it permenant. They used them in place of signatures. So without any doubt whatever - the Quran didn't predict or explain anything that wasn't already well-known. If you were honestly curious - you could have looked at that article and discovered precisely what I discovered. But even if we somehow deny all of these older instances of an understanding that fingerprints are unique - you can't claim that this one sentence in the Quran says ANYTHING about fingerprints being unique. Just read the darn thing! It says that they are in "perfect order" - I can't make my brain go from "perfect order" to "completely and utterly random and different on every single person in the world"! How can those two things POSSIBLY mean the same thing?! So the Quran didn't predict or explain ANYTHING - in fact (if we are to believe that it's talking about fingerprints at all) it stated completely the opposite of the truth! I don't know whether you plan to drop these supposed "facts" from the Quran on us every few days in the hope that one of them will be convincing - but honestly, it's pointless - I can tell you - in advance - that not one of them will turn out to be true...not one. So if you really must - why not get it over and done with in one go. Just list the whole phreaking list in one question and I promise that I'll personally go through the list disproving every single one of them - with references. If you're honest - then you'll have to admit that this stupid book is as big a pile of crap as all of the other "great" religious books of the world and then we can go back to answering questions from people who aren't trying to push an agenda. Sadly, I know you won't do that because you're brainwashed. You don't give a damn about the answers - you just have some vague hope that we'll be dazzled by the impressiveness of a 1400 year old book...but we're not going to be. If the Quran contained all of these deep scientific and technological truths - how come none of the consequences of that was ever discovered by the people who live and die by that book? Most of math, science and technology comes from the christian world...and mostly from atheists living within the christian world. Religious teachings ALWAYS act to suppress advances in science and technology...the Quran is no different. SteveBaker (talk) 02:58, 16 February 2009 (UTC)
dear Mr steve .. you hav'nt disprove any of them . about finger print ... the statment says that god will recreat evry one of us that he will even rebuild his finger tips ... god want to show you that he is cabaple of reproducing your body after its turned into ashes that he will even build your finger tips back .... translation may not give the same meaning , because languages are different , that i can't help you with . and why the people who lived by the book had'nt dicover any thing , because they are no ascientiests , they are an ordinary people , what its gonna mean if they discover it 1400 years ago . arab world became the most advanced in the world , because they lived by the book , bibble and tawrah is the book of god as mush as the quraan , but we missed the two up , that god send the last one (quraan) to be the last , surly god didnt leave people before islam lost in the world . and finally , i will list up what i know , and wait for your answers , and before you answer read the explanation of it , and dont expect to find some mathmatical expression in it , such science could'nt be expressed by arabic language that time , the word was'nt enough . i look at indian scientist worshiping caws , mabey i'am justlike them and maybe not , at least i considering the possibility , why dont you , you could be wrong either Mr steve . —Preceding unsigned comment added by 79.173.227.192 (talk) 07:34, 16 February 2009 (UTC)
- So you've changed what you were saying. You asked us to comment on a video that said that the Quran predicted that fingerprints are unique. I clearly showed that not only does it not say that - but also it didn't say whatever it actually DOES say until a couple of thousand years after the fact was already well known. Now you are just saying that the Quran tells us that god will rebuild us or something - that's a completely different matter - it doesn't say anything about predicting that we all have unique fingerprints - which is what you asked us to discuss. So did we answer your question by proving that the Quran DOES NOT predict unique fingerprints? If so - then we're done here. SteveBaker (talk) 15:45, 16 February 2009 (UTC)
- You're not listening and I'm not going to repeat it all. You clearly aren't here to learn, you just want science to prove Islam right, and that's not going to happen. Please stop posting here. --Tango (talk) 12:04, 16 February 2009 (UTC)
- And what does this book say about aggregates (previous question above)? Bazza (talk) 14:54, 16 February 2009 (UTC)
- What's the point of debating this? Either the Quran did have scientific facts in it, or it did not. Lots of books have lots of important information buried in lots of noise, and suffer from widely interpretable translation artifacts. But you don't see scientists running around quoting Principia Mathematica verbatim (Quantitates materiae in corporibus funependulis, quorum centra ossillationum a centro suspensionis a qualiter distant, sunt in ratione composita ex ratione ponderum & ratione duplicata temporum oscillationum in vacuo!) We have better ways to say the same thing, rendering the original text obsolete, and as a scientific community we can move forward. If the material is relevant, the truth of it will be self-evident. The mindless task of deciding attribution, or assuming that the author was divine, divinely inspired, etc., is a question for the humanities desk, because that sort of thing is not a science question. Nimur (talk) 16:59, 16 February 2009 (UTC)
On ancient languages being incapable of saying "fingerprints are unique"
[edit]- You made an assertion at one point that they had no way to say "fingerprints are unique", so said the closest thing they could in the language at the time. I disagree. If they didn't have a word for fingerprints, they could have said something like "the patterns on the skin on tips of the fingers, on the underside, opposite the nail, are different for each person and each finger". This would work without the words "fingerprint" or "unique". Most concepts can be described without words needed for the concept itself, by using more words. This is what a dictionary or encyclopedia does, after all (or at least what they're supposed to do). StuRat (talk) 16:44, 16 February 2009 (UTC)
our discussion is if the quraan is god word or not , so we will assume that it was made by god , which lead to the fact that these is gods word not ours . i can give you alot of similar examples , but assuming that god want to talk about the earth , god mentioned that he had created seven earthes , its not clear unless you search for it to find that earth is made of seven layers , not three as we use to know , it was meant to remain unexplained until we explain it , so to be like aguide , aprove that this book is the word of god . will the question is is it acoincidence that seven earths were used , or mabey the fact is just wrong, or what and finaly , even if any one could proof that there is ascientific facts in quraan , its very easy to say , avery advanced civilisation had lived before us and this is just their remains . its easy to ignore it , to assume any thing . my friend , i'am not arelegious man , yes i'am amuslim but i'am not really amuslim if you know what i mean , just like chrestians these days , i'am just trying to find the truth , no thing i said were disapproved , they all make assumptions , like coincidences and such , from where did we come , evolution , mabey ,its just theories . all i'am asking is try to be neutral , admmit the possibility that this could be true . and please dont get angry , i'am not your enemy , thank you any way . —Preceding unsigned comment added by 86.108.53.185 (talk) 18:20, 16 February 2009 (UTC)
- I don't see why "words having come from God" would mean that they must be so vague they could be interpreted to mean just about anything. Why exactly would God want to give us confusing descriptions instead of clear ones ? As for your example of "7 Earths", it's quite a wild assumption to take that to mean "one Earth with 7 layers". And, even if you did (mis)interpret it that way, you could say the Earth is made of just about as many layers as you want. Just the atmosphere could be said to have 7 layers, if you wanted to define it that way. So, if you combine being able to interpret holy words in any way convenient and being able to interpret science in any way possible to get a match, you will find you can "prove" just about any holy words you want. StuRat (talk) 19:19, 16 February 2009 (UTC)
- Islam teaches that only the original Arabic is God's word - you're talking about translations of God's word, and often serious mistranslations. --Tango (talk) 22:50, 17 February 2009 (UTC)
- Do you seriously imagine that the Arabic version is any clearer on these points? SteveBaker (talk) 14:32, 18 February 2009 (UTC)
- No, I don't think many of the points exist at all in the Arabic version (they barely exist in the English ones). --Tango (talk) 17:20, 18 February 2009 (UTC)
- Do you seriously imagine that the Arabic version is any clearer on these points? SteveBaker (talk) 14:32, 18 February 2009 (UTC)
On the predictive nature of good theories
[edit]- While it's one thing for a theory to be able to be adjusted to fit data that doesn't fit initially, it's certainly not a proof that the theory is correct. What would be a partial proof is if the theory allows us to predict things accurately. For example, was there anything in the Koran which clearly pointed to the date of the tsunami ? (I mean so clearly that everybody reading it would have been sure that it could only mean that date, before the event occurred.) No, of course not. If so, then all believers would have evacuated the coastal areas on that day, but they didn't. StuRat (talk) 19:29, 16 February 2009 (UTC)
Question about the nature of the expanding universe
[edit]Hi, my question is ver stupid but here it goes. What is beyond the expantion? 1) Nothing?? in this case we can say that "the expantion of the universe" is creating "space" as it keeps going. 2) Empty space? in this case we can say that our big bang could be just one of "many big bangs" going on at other points of that "empty space" I think this question is a little confuse.. sorry about that and thanks for the future answers. --Starlingmaximilian (talk) 20:28, 15 February 2009 (UTC)
- There are two acceptable answers. One is "nobody knows and we don't have any good way of knowing." Not very interesting but technically true. The other is "nothing is necessarily beyond it, as far as we understand it"—that is, the expansion of the universe is creating "space" as you put it, it isn't expanding into anything. Whether people lean towards one or the other interpretation seems rather arbitrary to me, but in any case the answer given isn't ever going to be "empty space", at least, other than that being a possible answer in the "nobody knows" sense (which would make it as valid an answer as, say, "butterflies"). --98.217.14.211 (talk) 20:36, 15 February 2009 (UTC)
- Neither. It's not really clear whether the universe is infinite or whether it 'wraps around' in some manner...but in either case, there is no "edge" of the universe - and therefore no "beyond". We've tried to explain that here MANY times - but the thing people don't "get" is that it's not that objects in the universe are moving apart so much as it is that space itself is stretching. This gives the impression that things are moving apart - but essentially, they are staying still while space itself stretches. SteveBaker (talk) 20:41, 15 February 2009 (UTC)
- SteveBaker has it right. Try it from this perspective. The simplistic view is that the Big Bang was a singular event. People often view it as a massive explosion which "pushed" objects outward, and that the expansion we see is merely the inertia of these objects which they carry from this initial push. Its a nice, easy to understand image, and like most of "real" physics, it doesn't match what is really going on. The more complete view is that the Big Bang is the process of space creation. Under this understanding, space is created between the galaxies; they don't actually move of their own accord. The Big Bang is not a singular event, its an ongoing process. The problem with the "explosion" explanation is that, if it were true, we could observe the motion of the galaxies, and identify a "center" of the Universe from which the matter was moving away from. Except, when we look at the whole observable Universe, the grand picture is not of galaxies moving away from a central point of explosion, its of all galaxies moving away from each other uniformly. That only makes sense if there is no center of expansion; and the "creation of space" model fits the observations much better than the "big explosion" model. --Jayron32.talk.contribs 20:53, 15 February 2009 (UTC)
- Could we not be in a volume of space that is shrinking in a pervasive way such that none of our local measurements seem to be affected, embedded in a static infinite Universe ? Cuddlyable3 (talk) 21:54, 15 February 2009 (UTC)
- How are you defining "shrinking"? If our measurements of its size are staying the same then, by any reasonable definition I can think of, its size is staying the same. --Tango (talk) 21:56, 15 February 2009 (UTC)
- Could we not be in a volume of space that is shrinking in a pervasive way such that none of our local measurements seem to be affected, embedded in a static infinite Universe ? Cuddlyable3 (talk) 21:54, 15 February 2009 (UTC)
- By shrinking I mean you, me and all our tape measures getting smaller. An astronomer on a distant galaxy who is also shrinking could be looking towards us right now, measuring our sun's red shift and calculating how much closer we are than them to the time of their equivalent B. Bang concept.Cuddlyable3 (talk) 19:12, 16 February 2009 (UTC)
Universe can't be infinite, it must be an "edge", call it "end of the space" or "Matter moving from initial inertia". If space is tretching is because it has a limit!! and if is being created it has a limit as well!!! I found 98.217.14.211's answer very satisfactory, cause i don't know about phisics but is philosophically impossible that the universe doesn't have a "dinamic edge" —Preceding unsigned comment added by Starlingmaximilian (talk • contribs) 22:04, 15 February 2009 (UTC)
- It's difficult to get your head around, I know, but the universe doesn't have an edge. Either it's infinite (trying to understand how the big bang works in an infinite universe is a sure fire way of giving yourself a headache!) or it has a closed shape - think of the surface of a balloon, as you blow it up the surface expands, but it doesn't have an edge. --Tango (talk) 22:10, 15 February 2009 (UTC)
- In the baloon example the "edge" would be the last layer of rubber of the ball, and the "beyond" the air surrounding it... sorry... i'm very troublesome :)
- No, we're just considering the surface of the balloon - the idealised 2-dimensional object. --Tango (talk) 22:32, 15 February 2009 (UTC)
- Ok, In the baloon example the "edge" would be the unique layer of the ball (sphere), and the "beyond" is whatever outside the ball, it may be "the nothing" "the lack of space" call it as you like. —Preceding unsigned comment added by Starlingmaximilian (talk • contribs) 22:47, 15 February 2009 (UTC)
- Inside and outside are references to the 3rd dimension, we're just talking about the 2D surface. Imagine you are a tiny ant walking around on the surface, there is no edge that you can fall off. --Tango (talk) 22:54, 15 February 2009 (UTC)
- Ok, In the baloon example the "edge" would be the unique layer of the ball (sphere), and the "beyond" is whatever outside the ball, it may be "the nothing" "the lack of space" call it as you like. —Preceding unsigned comment added by Starlingmaximilian (talk • contribs) 22:47, 15 February 2009 (UTC)
- No, we're just considering the surface of the balloon - the idealised 2-dimensional object. --Tango (talk) 22:32, 15 February 2009 (UTC)
- the body of the aunt is in "the nothing" in your example (obviosly impossible) and only the feet of the aunt are in contact with the sphere, but yet, outside. —Preceding unsigned comment added by Starlingmaximilian (talk • contribs) 23:16, 15 February 2009 (UTC)
- Indeed, as with any analogy it breaks down if you look too closely. The ant is meant to be infinitely thin - it's just an analogy to help make it easier to understand. Obviously, the universe is 3D, not 2D, but the principle is the same. --Tango (talk) 23:37, 15 February 2009 (UTC)
- the body of the aunt is in "the nothing" in your example (obviosly impossible) and only the feet of the aunt are in contact with the sphere, but yet, outside. —Preceding unsigned comment added by Starlingmaximilian (talk • contribs) 23:16, 15 February 2009 (UTC)
- I told you that this was going to be the problem! We've explained this at least a dozen times - and every time our OP gets stuck at the same point. We explain the balloon analogy and it doesn't help. How about the chocolate chip cookie analogy? If you buy raw cookie dough - a blob about an inch across can be placed on a baking sheet and after you bake it, you have a cookie that's about four inches across. With chocolate chip cookie dough, you start of with something that seems to be almost all chips - but after you bake it, they are quite far apart. So - the chocolate chips are...galaxies say...the dough is space. As the dough cooks every chip gets further from every other chip. No matter which chip is "you" - it seems like all the other chips are moving away from you - and the further they are at the outset - the faster they'll seem to recede. Now - if your original piece of cookie dough was infinitely big - and you baked it in an infinitely large oven - the result would still be infinite and every chip would see every other chip receding from it. SteveBaker (talk) 02:29, 16 February 2009 (UTC)
- The problem is that REALLY BIG PHYSICS and really small physics work very non-intuitively. That is, the laws which govern the way the REALLY BIG THINGS (like Galaxies) and the really small things like atoms, do not obey the same basic laws which govern the medium sized world we live in. Basic Newtonian physics, where infinity has no meaning, where I push something and it behaves as I expect it, where waves are waves and objects are objects, describes the medium-sized world very well. However, when we actually make observations and measurements of the REALLY BIG STUFF (like galaxies) and of really small stuff (like atoms) the laws that seem to work well for the medium-sized world just don't apply. So entire new sets of laws and theories needed to be created to account for these differences in observations.
- Now here's the kicker, these new laws and theories work perfectly well, they are mathematically and observationally consistant, they just don't make any sense. By that I mean that our unaided senses give us certain information about the world. That information leads to an intuitive model of how the world is supposed to work. It's almost subconsious; a 6-year old probably has the same intuitive model that a 30-year old does. The problem is that this model we have created for ourselves does not match the way that the REALLY BIG STUFF and the really small stuff works. So, you get the sort of incredulity that the OP expresses. At some point, if you are going to understand how the universe works on a cosmological level and on a subatomic level, you are just going to have to ditch everything you intuitively understand and accept what the actual data and observations are really telling us about how it really works. --Jayron32.talk.contribs 04:04, 16 February 2009 (UTC)
Well, it may be true that my intuition is playing me tricks... and i cannot accept examples like the balloon or the cookie... they always have a catch... but even if my intuition is making me unable to understand i can't let it apart.. i cannot accept something that don't makes sense, even if observations and maths tells me the oposite. Lets just keep it like this guys :), but one last thing, if any of you knows about any documental video explaining this subject please post it here and i will watch it. Also i want to thank 98.217.14.211 SteveBarker, Jayron32 and Tango for all the time you took in order to explain this subject to me, thanks to people like you wikipedia is as big as it is, thanks a lot guys. --Starlingmaximilian (talk) 10:05, 16 February 2009 (UTC)
- Yes - there is a very real sense in which our minds are not evolved to deal with Quantum physics and the various large scale weirdnesses. However, if all else fails, you can punt on the idea of having a mental picture of what's going on - and instead just rely on the observations and the math. Sadly, you have to accept the reality of it because it is true. Nothing else can explain the observation that every object in the universe is moving away from us - and the further they are from us, the faster they are moving away. You can prove that with a spectrometer and a backyard telescope - so there is really no doubt that it's true. But getting your head around the concept that something can be both infinite and expanding is tricky. Then when you're told that it's space itself that's doing the expanding and all of the objects within it are more or less stationary...that is REALLY tough to envisage. So you have to believe it's real - even though you can't envisage a nice analogy. Trust the math. SteveBaker (talk) 15:22, 16 February 2009 (UTC)
- Most scientists consider the universe to be "flat" - that is, if you were to look at the edge of the universe, it would be exactly flat. So it's an open universe, not round or closed, and it has infinite size. However, the "edge" would still be expanding "outward", that is, away from itself and its contents. ~AH1(TCU) 16:36, 16 February 2009 (UTC)
- There are empirical limits on how curved the universe can be, but I'm not sure it's true to say most scientists think it is completely flat. Even if they do, it doesn't follow that it's open - a 3-torus is closed and flat (when we think of it as embedding in higher dimensional space it has an extrinsic curvature, but it doesn't have intrinsic curvature which is all that matters in this context). --Tango (talk) 19:02, 16 February 2009 (UTC)
- Most scientists consider the universe to be "flat" - that is, if you were to look at the edge of the universe, it would be exactly flat. So it's an open universe, not round or closed, and it has infinite size. However, the "edge" would still be expanding "outward", that is, away from itself and its contents. ~AH1(TCU) 16:36, 16 February 2009 (UTC)
Okay, first, there was no big bang. Big Bang cosmology isn't about a big-bang event and doesn't say that there was one. It's misnamed. Second, we don't know whether there's an edge. The cosmological model we use doesn't have an edge in it, but there's no reason to think that it models the whole of existence. We already know it doesn't work farther back in time than ~14 billion years, and it doesn't necessarily apply further than some finite distance in space either. It's a mistake to assert that the universe has no edge just because the model doesn't have one. We couldn't directly see or otherwise detect any edge because of the light speed limit anyway. Third, as I keep saying, the cosmological expansion is just galaxies moving apart. It is not galaxies standing still while space is created between them. There's no way to invent a coherent concept of "creating space" because space doesn't have the properties of a substance. There's no conservation law for space. All of the space at any given time is brand new: it's all-new points in spacetime. The principle of relativity implies that you can't associate any particular point in space right now with any particular point in space at an earlier time (in contrast to ordinary matter, where you can trace back the worldlines and tell which matter is new and which has been around for a while). The other reason you can't talk about creating space is that the physics governing the separation of the galaxies is exactly the same physics governing the separation of any other two objects. These situations aren't distinguished in any way in the mathematics, and there's no natural dividing line you can draw between them. When an astronaut on a spacewalk drifts away from the shuttle, space is being created between him and the shuttle in exactly the same sense that space is being created between the galaxies in the cosmological expansion. It's all relative motion. If we knew the volume of the whole universe, and it was finite, it would be increasing with cosmological time, and you could describe that as an "overall expansion of space", but I would still strongly discourage that because everything I said above still applies. Physics is local; the universe doesn't care about quantities obtained by integrating over large quantities of space at a fixed cosmological time. Each bit of spacetime is doing its own thing, whether or not an overall volume can be defined. -- BenRG (talk) 18:24, 16 February 2009 (UTC)
- I still don't get that. How does that work for, say, a 3-sphere? What are the momentum vectors for each galaxy at a given moment of time (in a given reference frame, it doesn't really matter which)? I can't see any way they can all be pointing away from each other. Somewhere you would need to have a region of space that is contracting, which doesn't fit with any theory of cosmology I've heard (except for contractions on very small scales, which don't help here). --Tango (talk) 19:02, 16 February 2009 (UTC)
- Okay, here's the best answer I can come up with for this. The key points are: 1. The relative motion of galaxies and the relative motion of astronauts are essentially the same. This doesn't mean they're both special relativistic—they're not, they're both general relativistic. It's like saying that separation at 1 m/s and separation at 299,000,000 m/s are essentially the same, even though Newtonian physics gets one of them right and not the other. Think of the small-scale stuff in general-relativistic terms, not the large-scale stuff in special-relativistic terms. 2. Physics is local—the spacetime over here doesn't care about what the spacetime over there is doing, at least not directly. Suppose first of all that space has an edge. An edge of space, unlike the bulk, would have to have a state of motion. Suppose it's moving in roughly the same way as the galaxies in that region. Then, since the galaxies are moving away from neighboring galaxies, which are moving away from..., etc., all the way across the universe, the distance between the edges is also increasing, so the overall volume of space is increasing. However, the universe doesn't "know" this—all evidence suggests that different parts of the universe evolve independently. Locally, objects are just moving apart in the same way they would otherwise. In the case that space doesn't have an edge but closes around on itself, it's the same story. Locally, you have a net positive curvature that's due to the density of matter being a bit higher than the critical density. As matter continues to separate and thin out that density decreases and so does the curvature, though it remains positive. Global consistency requires that the total volume of space increased, but locally it doesn't matter. Locally there might as well be an edge moving "inward" at such a speed that the total volume remains constant (and eating up galaxies in the process, I suppose). In that case you might interpret it as galaxies flying outward through fixed space until they reach the edge instead of as fixed galaxies on an inflating balloon, but the universe doesn't care one way or the other.
- The other thing is that it's somewhat arbitrary how you define the volume of space in the first place. Everyone knows that space is flat when the matter density equals the critical density and hyperbolic when it's lower than that. In particular, space is hyperbolic when the density is zero. But given that curvature is supposed to be due to the presence of matter, shouldn't it be flat in that case? In fact what's going on is that the Ω=0 limit of the FLRW cosmology is just a part of (flat) Minkowski spacetime, but the coordinates are such that the ones interpreted as "spatial" happen to cover a hyperbolic surface in Minkowski space for any given value of the "time" coordinate. If you look at the same cosmology in Minkowski coordinates, taking Minkowski x,y,z to be "space" and t to be "time", it looks like a finite flat space with a spherical boundary that's growing with time (at the speed c), instead of an infinite hyperbolic space with no boundary. Same physics, different coordinates. The Euclidean analogy for this is Cartesian versus polar coordinates. If you take Cartesian x,y to be "space" and z to be "time" then space is flat and infinite, but if you take θ and φ to be "space" and r to be "time" then space is spherical and finite and growing with time. A similar thing happens with de Sitter space, which is the exponentially inflating spacetime that was the past of our universe (according to inflationary cosmology) and also the future (according to ΛCDM). Cosmologists like to say that it's spatially flat (and infinite) and exponentially expanding (i.e. the scale factor goes like et), while mathematicians are more likely to say that it's spatially spherical (and finite) and the scale factor goes like cosh t. This is two different coordinate descriptions of the same thing. The universe doesn't care about global coordinate systems, and we probably shouldn't either. -- BenRG (talk) 23:19, 17 February 2009 (UTC)
Ok, i really like the point of view of BenRG, but if theres no space creation what do you understand with "origin of the universe"? i mean, if space is not "created" that means that the "origin of the universe" is just matter getting separated from his original point and that space was always there. But if you say that that would mean that many "origins of the universe" might be happening really far away of us, and maybe in an uncertain future colide with our "universe", but if we believe this, the word "universe" doesn't aplly anymore... do you really say that there was no "space cration" at the origin of the universe?? or maybe i got you wrong. --Starlingmaximilian (talk) 00:29, 17 February 2009 (UTC)
- Our current theories only explain things back to a tiny fraction of a second "after the big bang", we don't know what happened before that (we talk about there being an "infinitesimal singularity" that went "bang", but "singularity" is just what physicists say when they don't actually know what's going on). --Tango (talk) 15:55, 17 February 2009 (UTC)
- That was the traditional big bang, but in modern inflationary cosmology they do think they know what was going on and it's not a big bang singularity. The ΛCDM scale factor at very early times looks something like , which obviously goes to 0 at t=0. That's the big bang. However, in inflationary cosmology there's a time tR > 0 before which the scale factor is exponential instead due to non-ΛCDM physics, so overall you have something like
- where I put in factors of e and 1/2 to make a and a' match up at the crossover point. Real inflationary models are not this crude—there's a gradual transition between the models, not a grafting together of two different functions—but I think this gives the right general idea. The interesting thing here is that this new function never reaches zero, no matter how far to the left you go, so this model no longer has a natural beginning-of-the-universe. That doesn't mean there wasn't a beginning of the universe, but it does mean you should forget about the idea that there was a big bang at t=0. Nothing special happens at t=0; it's just a mathematically convenient origin point for the ΛCDM part of the model.
- Incidentally, it's worth pointing out that the inflationary expansion is slower than the ΛCDM expansion in the regime where it actually takes place (i.e. before tR). People are fond of saying that inflation causes the scale factor to increase by a factor of in 10−30 second, but they neglect to mention that the ΛCDM expansion would have increased it by a factor of infinity (from 0 to a nonzero value) in an even shorter time. In fact, inflation is so slow that it takes literally forever to get from zero to a(tR) (not that anyone thinks this simple model is valid arbitrarily far back in time). Inflation solves the horizon problem by being enough slower than ΛCDM that causal influences have time to cross the whole observable universe (which was very small back then, but not small enough to compensate for the quickness of the ΛCDM expansion). Also note that the duration of inflation is much longer than the "time after the big bang" at which it ends (in other words, inflation starts at t/tR << 0). Or so it would seem, anyway. I don't think I've ever seen a description of inflation that mentioned either of these things explicitly, so I may be missing something, though I don't know what it is I could be missing. It would be nice to have some sources so I could either fix my thinking or fix Wikipedia's cosmology articles. -- BenRG (talk) 23:19, 17 February 2009 (UTC)
- That was the traditional big bang, but in modern inflationary cosmology they do think they know what was going on and it's not a big bang singularity. The ΛCDM scale factor at very early times looks something like , which obviously goes to 0 at t=0. That's the big bang. However, in inflationary cosmology there's a time tR > 0 before which the scale factor is exponential instead due to non-ΛCDM physics, so overall you have something like
Coming from the inflation page, if space grew at a speed faster than the speed of light, then even though at a time before inflation light could travel across the whole universe, wouldnt info still not reach the edges of the universe (if there even is one) even traveling at the speed of light?--GundamMerc (talk) 15:44, 17 February 2009 (UTC)
- It's not true that inflationary expansion is faster than light (a lot of books claim it is; they're all wrong). It is true that causal influences can't necessarily cross the whole inflating spacetime, but they only need to cross a part somewhat larger than our present-day observable universe to explain what we see. The uniformity that we see doesn't necessarily extend forever. -- BenRG (talk) 23:19, 17 February 2009 (UTC)
Do you edit on the redshift page, i think you would be useful there (groans inside at the different editors taking philosophical sides during discussion). Oh, and thanks for the help with that question.GundamMerc (talk) 12:29, 18 February 2009 (UTC)
Boiling to Death
[edit]I read our article on the concept, my question is though, what is the cause of death?
Does the skin slough off? Can the lungs not take in air if it's too hot? Does the blood boil in the veins?
Why would being immersed--not drowned, just immersed, in boiling hot water--kill someone?24.91.161.116 (talk) 21:34, 15 February 2009 (UTC)
- Warning, the following link contains explicit images of a decomposed human corpse which may be distressing to some readers
- If you really have to see. Please don't try this at home. Cuddlyable3 (talk) 21:44, 15 February 2009 (UTC)
- That link is not safe for... um... anywhere from where you can see the computer screen... --Tango (talk) 21:50, 15 February 2009 (UTC)
- I am apalled that the police could even consider releasing that picture on to the internet. The man must have relatives. SpinningSpark 00:53, 16 February 2009 (UTC)
- I just feel bad for whoever cleaned up. Zain Ebrahim (talk) 15:00, 17 February 2009 (UTC)
- I am apalled that the police could even consider releasing that picture on to the internet. The man must have relatives. SpinningSpark 00:53, 16 February 2009 (UTC)
- That link is not safe for... um... anywhere from where you can see the computer screen... --Tango (talk) 21:50, 15 February 2009 (UTC)
- An interesting question... Obviously your skin would burn, but I'm not sure that would be the cause of death (death from skin burns usually takes some time, as I understand it, I expect death by boiling to be reasonably quick). Boiling water entering the mouth or other orifices could cause internal burns, which could be more fatal (causing internal bleeding, damaging lung tissue and causing suffocation, etc.). Or, death could simply be by hyperthermia, getting too hot - if your core body temperature gets above about about 40 degrees, you're in real trouble, and I guess it wouldn't take long to get up to such temperatures when immersed in boiling water. --Tango (talk) 21:46, 15 February 2009 (UTC)
- Quite simply, the cause of death would be the symptoms pertaining to hyperthermia. Your blood pressure would drop like a stone, dehydration, tachycardia (this could be the big killer here) etc. When your heart fails, you can no longer supply cells with oxygen and you will essentially die from that. Also, when you become unconscious, there's a risk of drowning. —Cyclonenim (talk · contribs · email) 23:18, 15 February 2009 (UTC)
- One time, a girl fell into an area where the water was boiling in Yellowstone, after getting out of a hotspring. She was in the boiling water for seven seconds, and then she was dragged onto a cold river to cool for 45 minutes. She didn't survive. ~AH1(TCU) 16:33, 16 February 2009 (UTC)
- That probably wasn't the best treatment... In just 7 seconds I expect the only damage would be burns, hyperthermia wouldn't have set in yet. The first aid for burns covering more than about 1% of the body (and 100% is more than 1%!) is not to cool it since that will just cause hypothermia, but rather to go straight to hospital (after wrapping the effected area in cling film). Of course, this should not be taken as medical advice - if you want to learn first aid, take a first aid course! Even with correct treatment, though, her chances of survival would have been pretty slim. --Tango (talk) 18:42, 16 February 2009 (UTC)
- One time, a girl fell into an area where the water was boiling in Yellowstone, after getting out of a hotspring. She was in the boiling water for seven seconds, and then she was dragged onto a cold river to cool for 45 minutes. She didn't survive. ~AH1(TCU) 16:33, 16 February 2009 (UTC)
- Quite simply, the cause of death would be the symptoms pertaining to hyperthermia. Your blood pressure would drop like a stone, dehydration, tachycardia (this could be the big killer here) etc. When your heart fails, you can no longer supply cells with oxygen and you will essentially die from that. Also, when you become unconscious, there's a risk of drowning. —Cyclonenim (talk · contribs · email) 23:18, 15 February 2009 (UTC)
Cream Smell
[edit]My girlfriend uses a skin cream which reminds me of doctors. Just smelling it immediately makes me think of hospitals.
I'm wondering which ingredient in this cream is the cause:
they are as follows: Aqua, Glyceryl, Stearate SE, Glycerin, Lanolin, Alcohol, Benzyl Alcohol, Cetearyl Alcohol, Oleic Acid, Triethanolamine, Stearic Acid, p-Chloro-m-Cresol, Parfum (Fragrance), Linalool, Limonene, Citronellol, Courmarin, Geraniol, Anise Alcohol, Benzyl Cinnamate
is one or several of these a main component of the bandages/first aid/ointment smells of hospitals?24.91.161.116 (talk) 21:39, 15 February 2009 (UTC)
- The alcohol (ethanol) and benzyl alcohol are both common solvents and disinfectants that are found in many medical products; they both have a fairly distinctive odor that you may associate with hospitals. Triethanolamine also has an ammonia odor which again could be associated with all sorts of medical products. p-Chloro-m-Cresol, if I recall right, has a distinct odor of phenol, which is another common disinfectant which has a very distinctive smell - if I had to bet, I'd say that is likely to be the culprit. Phenol makes me think of hospitals too, it's a very horrible and very distinctive medicine-like smell. The last eight ingredients are all substances specifically added for their smell; and are all common components of perfumes and cosmetics - it's unlikely you'd associate any of those with hospitals, though again it's possible. ~ mazca t|c 23:29, 15 February 2009 (UTC)
- yes, I've spent too much time sniffing chemicals at university. I'm surprised I'm not dead. ~ mazca t|c 23:29, 15 February 2009 (UTC)
- Mmmm I would say the alcohol would definitely be methanol and its unlikely you are smelling that over the Parfum (which means perfume) or the Lanolin. The methanol that normally goes into these products has almost no smell. I know you may be thinking 'Hey, I've smelled rubbing alcohol before and I know it has a smell,' but that isn't the methanol you are smelling; it is an additive to make sure you don't try and drink it. Benzyl alcohol is just a preservative and while it is found in IV solutions to keep them sterile, I don't think you could pick that out either. I have compounded many similar creams and would say that you could smell the lanolin. Most lanolin that goes into cheaper OTC products isn't necessarily medical grade and contains a lot of smelly fatty acids. Whether or not those smell like a hospital, I'm not sure. Mazca probably hit on the answer in one of his other suggestions, but I'll rule out methanol as a possibility. --Mrdeath5493 (talk) 01:30, 16 February 2009 (UTC)
- Yeah, you're correct on the topic of those alcohols - regardless of whether it's ethanol or methanol, in retrospect I doubt either would smell strongly enough to overpower the perfume ingredients. Benzyl alcohol does have a noticeable smell, I personally find - but again, you're right that it probably isn't strong enough. I hadn't thought about the lanolin - in its pure form it's basically odourless, but it's true that impure stuff could have all sorts of distinctive smells. ~ mazca t|c 10:50, 16 February 2009 (UTC)
- Actually I don't know what I was thinking with methanol. I was truly thinking isopropyl alcohol.
- --Mrdeath5493 (talk) 21:12, 17 February 2009 (UTC)
- The last few ingredients: "Linalool, Limonene, Citronellol, Courmarin, Geraniol, Anise Alcohol, Benzyl Cinnamate", are actually all perfume ingredients. The nasty hospital smell is likely p-Chloro-m-Cresol since cresol compounds smell bitter, irratating and "clean" in a hospitalish way. Triethanolamine may also contribute but I don't think its smell is strong enough to really register in this case. All the other ingredients that you see besides parfumcan be basically considered as scentless. Sjschen (talk) 16:53, 18 February 2009 (UTC)
- Yeah, you're correct on the topic of those alcohols - regardless of whether it's ethanol or methanol, in retrospect I doubt either would smell strongly enough to overpower the perfume ingredients. Benzyl alcohol does have a noticeable smell, I personally find - but again, you're right that it probably isn't strong enough. I hadn't thought about the lanolin - in its pure form it's basically odourless, but it's true that impure stuff could have all sorts of distinctive smells. ~ mazca t|c 10:50, 16 February 2009 (UTC)
The night sky
[edit]Is it possible to have a faint glow in the night sky around the moon during a lunar eclipse? There, you can both have your moments now. --Tango (talk) 21:48, 15 February 2009 (UTC)
- If you're referring to what I think you are, then I don't think a lunar eclipse is a very good time to look for it, as the eclipsed moon is still quite bright. According to Google, the best time is in the middle of a clear moonless night in late February (the time of year is relevant because you don't want the milky way to obscure the view). You realize it's no fun this way, don't you? Algebraist 21:57, 15 February 2009 (UTC)
- I know it's no fun, I just wanted to stop you two complaining... Shall I log out and word the question less obviously? --Tango (talk) 21:59, 15 February 2009 (UTC)
- Best wait a few months first. Algebraist 22:02, 15 February 2009 (UTC)
- But then I have to put up with you complaining for a few months... --Tango (talk) 22:03, 15 February 2009 (UTC)
- Best wait a few months first. Algebraist 22:02, 15 February 2009 (UTC)
- I know it's no fun, I just wanted to stop you two complaining... Shall I log out and word the question less obviously? --Tango (talk) 21:59, 15 February 2009 (UTC)
how i make small text? —Preceding unsigned comment added by 194.80.240.66 (talk) 13:20, 16 February 2009 (UTC)
- Uh, perhaps you could've looked at how Tango and Algebraist did it? In any case, anything you write between <small> and </small> is rendered in a smaller font size -- so typing "<small>small text</small>" results in small text. -- Captain Disdain (talk) 13:40, 16 February 2009 (UTC)
- Do you have an account? If you do, login and you get an expanded toolbar that includes a button with that feature. Or try Captain Disdain's suggestion. A Quest For Knowledge (talk) 13:43, 16 February 2009 (UTC)