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# Wikipedia:Reference desk/Archives/Science/2010 February 17

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# February 17

## Cabbage, salt and water... blue?

Hi all,

I'm making pickled cabbage. I shredded a bunch of red and savoy cabbage, sprinkled a few tablespoons of salt on it, and left it for 24 hours. Then I removed the cabbage. At the bottom of the bowl, there was a puddle of red liquid. I then brought the bowl to the sink and started pouring some water in it. To my surprise, the water turned bright blue!

Can anyone explain the chemical reaction that must have occurred?

Thanks! — Sam 76.24.222.22 (talk) 01:40, 17 February 2010 (UTC)

Red cabbage is a traditional pH indicator. [1] Dragons flight (talk) 01:43, 17 February 2010 (UTC)
The salt might have extracted the acidic component without extracting a basic component, maybe? John Riemann Soong (talk) 01:51, 17 February 2010 (UTC)
Very interesting. Any thoughts as to why it only appeared when I added water? (I was able to replicate this later.) I doubt my water is that basic! — Sam 76.24.222.22 (talk) 03:55, 17 February 2010 (UTC)
According to the "How to Make Red Cabbage pH Indicator" link on the Red Cabbage page, at pH 6 the solution is violet, and is blue at pH 8. I imagine at pH 7 it would be classified as "blue". Most tap water is around pH 7 (indeed, if it falls much outside that range, your water company will adjust the pH to avoid damage to the pipes and to keep the sanitizing power of the added chlorine). Now, why does the water *change* the pH? Most tap water isn't just H2O, it also contains a number of buffering agents, especially if it comes from something like a limestone aquifer. The buffering capacity of the water probably overwhelmed the small amount of acid in the cabbage drippings, bringing the pH back to ~7 and turning the color blue. It's not that the tap water was very basic, it's just that it was less acidic than the juice. -- 174.21.247.23 (talk) 04:10, 17 February 2010 (UTC)

## Orientation of the International Space Station

I've been watching live video of the STS-130 mission to the ISS online on NASA TV. At times (when they are not receiving video from the ISS) they display a graphic showing the ISS, from three views, as it orbits. From the relative motion of the Earth displayed below and what I assume are velocity and acceleration vectors displayed on the side view, it appears as if they are representing ISS orbiting with the Russian section leading and the shuttle, docked to PMA-2 (attached to Note 2, Harmony), trailing. This is the opposite orientation as described at International Space Station#Attitude (orientation) control. Exterior ISS video I saw yesterday of the PMA-3 attachment to Note 3 seemed to agree with the WP description. So, is the NASA graphic backwards, or do they occasionally reverse the orientation of the ISS, perhaps to help protect EVA crew from MMOD? 58.147.58.28 (talk) 01:53, 17 February 2010 (UTC)

It is hit and miss whether the orbital orientation graphic is displayed on NASA TV at any one time. I will try to find it in another source, but I don't know how easy that will be as it is not the sort of thing that typically makes it into the daily highlights videos. 58.147.58.28 (talk) 02:03, 17 February 2010 (UTC)
I haven't found another source for the graphic, but exterior ISS video of the EVA in progress showing Note 3, PMA-3, and cupola with the Earth seen moving below seems match the reversed orientation of the graphic. 58.147.58.28 (talk) 03:41, 17 February 2010 (UTC)
While the Shuttle is docked to ISS, the ISS attitude is yawed 180 degrees from normal such that the Russian Segment is in front and the Shuttle trailing, exactly as you describe. This is done to protect the Shuttle Thermal Protection System from micrometeroids and orbital debris. anonymous6494 08:49, 17 February 2010 (UTC)
Thanks. With the answer in hand I was able to search and find this reference which deals specifically with STS-130. I'd like to find one that mentions the practice in general, but I suppose that this one would be sufficient to expand International Space Station#Attitude (orientation) control. 58.147.58.28 (talk) 01:08, 18 February 2010 (UTC)
And I see that the orientation is back to normal as the shuttle undocks. (I missed the change which I assumed was done by the shuttle's RCS shortly before undocking). 58.147.58.28 (talk) 01:17, 20 February 2010 (UTC)
Correct! anonymous6494 05:07, 20 February 2010 (UTC)

## Linear density

I computed the linear dord of quartz for a question earlier using wolfram alpha as ${\displaystyle {\sqrt[{3}]{density}}}$. The units for the result are ${\displaystyle {{\sqrt[{3}]{g}} \over cm}}$. I understand why it gave that result, but it doesn't make sense. Shouldn't it simply be ${\displaystyle g \over cm}$? What did I do wrong? Ariel. (talk) 02:45, 17 February 2010 (UTC)

The cube root of density is the cube root of (g/cm) not the (cube root of grams)/cm. Plus "dord" isn't a real word - as you'd know if you'd followed the link you kindly left us! SteveBaker (talk) 03:02, 17 February 2010 (UTC)
I know dord isn't a real word. It was a joke. You and Jayron below you said exactly the opposite things about the units. Ariel. (talk) 03:14, 17 February 2010 (UTC)
(edit conflict)Density is grams per cubic centimeter, or g/cm3. Taking the cube root of that returns g1/3/cm or as you note above, the cube root of grams over centimeters. --Jayron32 03:05, 17 February 2010 (UTC)

If you take the cube root of g/cm3 you get g1/3/cm, and yet linear density is g/cm - so what gives? Ariel. (talk) 03:14, 17 February 2010 (UTC)

That's because linear density is defined as mass per length, NOT as the cube root of density. So, you are starting from the wrong premise. Linear density is NOT the cube root of density; its just grams per centimeter. Wouldn't it be nice if there were some sort of free information resource on the web where you could look this stuff up? --Jayron32 03:25, 17 February 2010 (UTC)
OK, so in that case, if I calculate: I have matter with a linear density of 2 g/cm, by 4 g/cm by 1 g/cm the density is then 8 g3/cm3. So then why is density defined as g/cm3? And I did look stuff up, I read Dimensional analysis and Quantity calculus, and density and Linear density, and none of them explained why the units don't work. Ariel. (talk) 03:41, 17 February 2010 (UTC)
Linear density is not defined for material in general, but for a structure in particular. To determine the linear density of your quartz bar you need to know its cross sectional area. The linear density is then the density divided multiplied by the area, not the cube root of the density.58.147.58.28 (talk) 03:48, 17 February 2010 (UTC)
(edit conflict) Linear density is sort of a specialized unit; you can't cube it and get actual density. To get denisty from linear density, you don't multiply the linear density in three dimensions, you divide linear density (g/cm) by the cross-sectional area (cm2) and then you'll get the density. The reason for this is that the linear density of a substance is a measure of all of its mass divided by its length in one dimension. If you want volume density, you need to include the other two dimensions in terms of length, but you don't need to count the mass again, since that number is already included in the linear density. So linear density divided by cross-sectional area will give you volume density (i.e standard density). --Jayron32 03:54, 17 February 2010 (UTC)
If your quartz bar had a cross section of 1 cm x 1 cm, its linear density would be 2.634 g/cm. If it had a cross section of 2 cm x 2 cm, its linear density would be 10.536 g/cm. — Sam 76.24.222.22 (talk) 04:00, 17 February 2010 (UTC)
Thank you all. I understand it now. For some reason I thought linear density is a measure of "number of units of mass" per length, i.e. that it's the same for all shapes of objects, just like density is the same for all shapes. Clearly my math in this question was wrong, and I will redo it. Ariel. (talk) 04:10, 17 February 2010 (UTC)
Yeah. Density is a intensive property because it is a property of the material itself irrespective of the amount of material. Linear density is NOT an intensive property, except in limited applications. Linear density is intensive with respect to length ONLY, and only if cross-sectional area is kept constant. If you alter the crosssectional area, you change the linear density of the material. It generally has to do with the applications of linear density. You only usually use it in situations where you are dealing with a material which you work with in relatively uniform, long amounts of it, like say yarn or railroad rails or 2x4's. You would, for example, be interested in the linear density of a particular type of cotton thread, but two different types of cotton thread would have different linear densities, even if the cotton fiber they were both composed of has the same volume density. --Jayron32 04:31, 17 February 2010 (UTC)

## Medical devices, WWII-era occupied Poland

The device in this archival photo was used in the Lodz ghetto, ca. 1940–1944. My questions: what is it, and was it used for diagnosis or for treatment? -- Deborahjay (talk) 09:08, 17 February 2010 (UTC)

And this one as well: same questions as above. -- Deborahjay (talk) 10:24, 17 February 2010 (UTC)

Guesses: First may be a medical diathermy machine. Second may be radiation therapy, or maybe just diagnostic x ray. The second setting is clearly institutional like a hosp x ray dept. The first setting may be a home doctors office. alteripse (talk) 11:12, 17 February 2010 (UTC)

Image one: From the position of the doc's hand and the direction of her gaze, I would say she is draining his left pleural cavity with a chest tube.
Image two: Certainly looks like a glass X-ray tube inside the enclose. I would think that under war time conditions of desperately severe shortages, all x-ray therapy would have been discontinued. It had very low success rates and so priority would have been given to diagnostic uses. Also, the woman has her hand on the x-ray collimator which is used to produce sharper x-ray images. --Aspro (talk) 18:18, 21 February 2010 (UTC)

## I'm on a barge travelling across Neptune, towed by a cable connected to the moon Psamathe...

... how fast would I be moving, if my moon-towed barge was skimming the uppermost clouds?

Thanks Adambrowne666 (talk) 11:15, 17 February 2010 (UTC)

Since the moon takes 9074.30 days to orbit neptune, your barge circles neptune once every 9074.30 days. Neptune has a circumference of 155600 km. So you are going 155600 km per 9074.30 days = 0.443952 miles per hour. Try this as well (click on the text of the result, then the orange link under it to get it in other units). Ariel. (talk) 11:38, 17 February 2010 (UTC)

wow - so that's what you plugged into wolfram alpha, and it understood what you wanted? Cool. Adambrowne666 (talk) 20:32, 17 February 2010 (UTC)

155600km / 9074.30days = 0.4440 miles per hour. Don't forget your significant digits. Dauto (talk) 14:25, 17 February 2010 (UTC)
As a comparison, a sloth will be cruising by you at 3x your speed. Googlemeister (talk) 17:24, 17 February 2010 (UTC)
Thanks, everyone. Of course, the Neptunian sloth is a little faster, so would be cruising by at almost 4X my speed. Adambrowne666 (talk) 20:32, 17 February 2010 (UTC)

I think it would be more natural to measure speed relative to the clouds, not relative to stationary space. Neptune rotates once every 16 hours. Your boat anchored to the moon is nearly stationary in the external frame, so if you are at the equator the clouds would be whizzing by you at ~9500 km / hr. Not exactly a leisurely pace. Dragons flight (talk) 20:52, 17 February 2010 (UTC)

A extremely good point! Here it is in wolframalpha. Since Psamathe has a retrograde orbit the speeds add. Ariel. (talk) 22:42, 17 February 2010 (UTC)
Yes, of course! thanks both of you, didn't think of that either. Adambrowne666 (talk) 23:08, 17 February 2010 (UTC)
Besides just orbiting Neptune, wouldn't Psamathe be rotating relative to Neptune? If you fixed the cable to a point on Psamathe and the cable stretched all the way to you on Neptune then the cable would start to wrap around Psamathe as the base point rotated relative to your position. Eventually, as Psamathe continued to rotate, you would be pulled from the surface of Neptune, into space, and dragged back onto Psamathe. Think of your sledge being a fishing hook, the cable a length of fishing line, and Psamathe and it's rotation as a fishing reel being wound backwards. •• Fly by Night (talk) 22:38, 18 February 2010 (UTC)
Yoiu could anchor your point at the rotational axis of the moon and limit this action. Googlemeister (talk) 15:42, 19 February 2010 (UTC)
Yes, good point, Flybynight, and good idea, Googlemeister - cable's hooked to a rotating joint on the moon's axis; also, it's able to play in and out to make up for Psamathe moving closer and further away. Problems solved, now let's get down to making it! Adambrowne666 (talk) 22:44, 21 February 2010 (UTC)

## Time Capsule

If I took my iPhone and buried it in a sealed vacuum capsule, how long would it remain useable (assuming the discovers could put in a new battery/power source). Which components would fail first? Would the OS start up? TheFutureAwaits (talk) 11:49, 17 February 2010 (UTC)

Indefinitely, I expect. You need to bury it deep enough that it won't suffer significant temperature changes, and you need to make sure the seal will last, but if you do that I can't think of anything that would damage it. --Tango (talk) 14:19, 17 February 2010 (UTC)
Does an iPhone contain any electrolytic capacitors? They eventually leak. Cuddlyable3 (talk) 14:34, 17 February 2010 (UTC)
Some types of battery can leak after a few years, however. 195.35.160.133 (talk) 14:56, 17 February 2010 (UTC) Martin.
You'd probably want to remove the batteries before you tried this. APL (talk) 15:38, 17 February 2010 (UTC)
How many years before the wireless technology has completely evolved and dropped backward-compatibility? I would estimate at least 25-30 years, but it's hard to say. Some analog mobile telephone technologies from the late 1980s are still supported by the transmitter towers and network providers; stepping even farther back, many land-line phone providers still provide support for rotary telephones or pulse dialing (probably using emulation with a software system). It seems plausible that 802.11 or "3G" GSM / WCDMA telephones might still be supported decades from now, even if they are no longer mainstream. Nimur (talk) 15:03, 17 February 2010 (UTC)
I wouldn't count on it. I had to replace my analog cell phone two years ago when the towers around here turned off their analog transmitters; the first-generation digital phone that replaced it lasted less than a year before the transmitters were turned off. --Carnildo (talk) 02:57, 18 February 2010 (UTC)
i would agree that any electrolytic capacitors are likely to become more leaky with time. Other components should not show significant ageing effects. However, some semiconductors may be compromised by the effects of nuclear radiation (gamma rays and cosmic rays). —Preceding unsigned comment added by 79.76.229.198 (talk) 15:36, 17 February 2010 (UTC)
After a while, tin whiskers may (or may not) start to form, these could cause shorts. The causes of tTin whiskers are not fully understood, so I'm not sure that a good estimate can be given.
This could theoretically be repaired by the benevolent future-people who also replaced the batteries, but it wouldn't be easy. APL (talk) 15:38, 17 February 2010 (UTC)
Dopants within semiconductors could migrate, rendering the chips nonfunctional, over a very extended time. You specified vacuum, which would prevent the oxidation of copper or brass I have seen in hundred year old telephones and telegraph instruments. But I have heard that vacuum can promote switch contacts welding together (that might apply more to those carrying high current, not so much a problem in a phone). It can also cause evaporation of films of lubricant which help switches and contacts operate. Vacuum would accelerate leakage of electrolytic capacitors. I would not expect typical rechargeable batteries to survive long storage under the conditions specified. Temperature variation could cause by the breaking of conductive paths and connections. Communications protocols will likely move on so that the signals used in the distant future would be incompatible with those used by a wireless phone of today. General Motors sold very expensive OnStar systems for car communication from 1996-2002 model years which became unusable after 2007 (this coming obsolescence was not mentioned at the times the expensive systems were being sold). The 1996-2002 system was analog, and was abandoned in favor of digital, with no retrofit of a new transceiver offered to keep the service going. From that example it is hard to see why operators of wireless systems would go to great lengths to make decades-old communications systems still operable. Planned obsolescence dictates that old software packages or hardware systems be "no longer supported" a few years later so the consumer has to shell out for a new one. Edison (talk) 17:21, 17 February 2010 (UTC)
Even with the cel-phone network gone or incompatible, the iPhone would still be a decent PDA. APL (talk) 18:41, 17 February 2010 (UTC)
One more angle, how long before Itunes is no longer backward compatible with version x (whatever version you bury it with), making it useless unless you posses the proper version of Itunes to perform intermediate updates? It won't be any fun to have to suffer along with the collection of music from right now... --144.191.148.3 (talk) 21:47, 17 February 2010 (UTC)
But this thing wouldn't be a practical/useful object after that much time. It would be a collectors item, a curiosity or a museum piece. In 20 years, we'll probably have a 1mm capsule that can be implanted behind your ear that runs on power generated from vibrations due to your heartbeat and not only comes pre-packaged with every piece of music known to mankind and can update with new music as it's recorded - but can compose new music in any desired style by itself. Why on earth would you care what music an antique iPhone could play? That's like asking why you can't get much rap music on 78 rpm shellac records. SteveBaker (talk) 02:35, 18 February 2010 (UTC)
Plastics are in fact not everlasting. There are many types of plastics and other materials on the circuitboard alone, not to mention the plastics in the casing. These will react with air or components in other plastics. I heard a museum curator remark that cellphones he were collecting would become brittle and disintegrate in just a matter of decades. The flash memory cards in the IPhone may also degrade over time, the technology actually relies on trapping electrons behind an insulating layer and I'm sure there's several ways that could be degraded. Add to that the problem with electrolytte capacitors mentioned above and I think we'll have to accept that many of us are going to outlive our gadgets, even if we store them in a cool dry place. EverGreg (talk) 09:39, 18 February 2010 (UTC)
Air in vaccum (okay I'm aware it's unlikely to be a perfect vacuum but you get the idea)? Nil Einne (talk) 22:51, 19 February 2010 (UTC)
Seal it in a 'dry nitrogen' atmosphere not a vacuum (a lot of military spares are packaged thus). It will also maintain a higher partial pressure to discourages the evaporation of the volatiles in plastic components.
A lead shield will help to mitigate natural radiation damage. Slow down chemical degeneration by cryogenic freezing -- then it might just last to the end of your warranty period. If you live in Poland, maybe not even that long [2].--Aspro (talk) 18:51, 21 February 2010 (UTC)

## Average world temperature

What is the average world temperature? I want to compare one country with an average of 21–33 °C with world average, but can’t find any reliable sources of world average. Caspian Rehbinder (talk) 13:59, 17 February 2010 (UTC)

The first picture of the global warming article might have the answer you are looking for. Dauto (talk) 14:33, 17 February 2010 (UTC)
Actually, the article I linked uses temperature anomaly instead of actual temperature. The article Temperature record since 1880 quotes: "1901-2000 global mean of 13.9°C". Dauto (talk) 14:45, 17 February 2010 (UTC)
This is can be a very difficult number to generate[3], and most sources will tell you the average variance per month, or the "anomaly." Here is a page that throughly goes through all of this stuff[4]. The website is biased in POV, but all the data is good and kept up to date. In short, according to United States National Climatic Data Center, the mean world temperature for January is 12.60 °C. When you compare the country's average temperature to that of the global average, make sure you compare the same years or months.Mac Davis (talk) 07:11, 18 February 2010 (UTC)
According to satellite data, global average temperature anomalies jumped from +0.29C in December 2009 to +0.72C in January 2010[5]. ~AH1(TCU) 00:54, 20 February 2010 (UTC)

## Ion list

Where can I find a complete list of cations and anions?--Mikespedia (talk) 14:13, 17 February 2010 (UTC)

The short answer is, "You can't". An anion is any moderately stable negatively-charged atom or covalently-linked collection of atoms, and there is an infinite number of such. Among the anions, there are a finite number of monatomic ones (like chloride, Cl-), but when you start allowing multiple atoms you get things like hypochlorite (ClO-), acetate (CH3COO-), and dodecyl sulfate (C12H25SO4-). It gets complicated fast. Our article on ions lists a very few monatomic and small polyatomic ions, but you can't create an exhaustive list. TenOfAllTrades(talk) 14:50, 17 February 2010 (UTC)
In other words, because there are an infinite number of stable ways to combine atoms, there are thus an infinite number of ionized forms. A comprehensive list might contain all the relevant ions for a particular domain, but it will never really be complete. Nimur (talk) 14:58, 17 February 2010 (UTC)
Since this is relatively answered, I'll steer it away with some nit-picking. Is there really an "infinite" number of stable ways to combine atoms? there clearly aren't an infinite amount of different components to molecules (elements and their isotopes), and I'm skeptical that their is an infinite amount of ways you can arrange atoms into molecules to get "stable" arrangements. I will add to this the note that I don't know nearly as much about chemistry as I would like, but the use of the phrase "infinite arrangements" for a concrete thing such as an Ions made question mark appear. Please elaborate if you don't mind, thanks! Chris M. (talk) 17:26, 17 February 2010 (UTC)
Actually, there probably are an infinite number of ways, owing to substances such as polymers and network solids. For example, a diamond is essentially a single giant molecule of carbon atoms, and something like polyethylene contains molecules containing millions of atoms each. With carbon-based molecules alone, there is no finite limit to the size of the molecule, so there is no functional upper bound to the ways they can be combined. --Jayron32 18:38, 17 February 2010 (UTC)
Ah, I had a feeling my lack of knowledge of chemistry would show when asking that question. Thanks! Chris M. (talk) 21:14, 17 February 2010 (UTC)

## Eating coffee beans

Say that I have a bag of coffee beans and wish to obtain the effects of caffeination, but I lack the means to grind and brew the beans to produce coffee. How much caffeination will I experience by simply eating the beans versus drinking brewed coffee? Do the digestive fluids "brew" the grounds in the stomach, or will they pass through the digestive system without yielding up their caffeine? 129.174.184.114 (talk) 16:16, 17 February 2010 (UTC)

Are you planning on swolling them whole? Dauto (talk) 16:40, 17 February 2010 (UTC)
Brewing doesn't create caffeine and there are a number of foods that include solid coffee beans (tiramisu, chocolate-covered expresso beans). But the results of civet cat consumption of raw beans is worth a mention: (Kopi Luwak). Rmhermen (talk) 18:34, 17 February 2010 (UTC)
Yes, I am aware that brewing doesn't create caffeine. My question is whether brewing in near-boiling water is necessary to release caffeine from the beans. In other words, if I eat coffee grounds (not intact beans), will the caffeine in the grounds leech out in my stomach or will the caffeine remain "locked" in the grounds? 129.174.184.114 (talk) 23:01, 17 February 2010 (UTC)
I'm pretty sure you will get the caffeine from the grounds, warm water may be slower than hot, but it's in you for much longer. If you don't crush (or chew) the bean you might not any from that though. Ariel. (talk) 07:41, 18 February 2010 (UTC)

## Cosmological argument and the fine-tuned Universe

I have browsed some related articles and from what I understand, the biological evolution is inapplicable in explaining the formation of the Universe and its components, as well as the symbiosis of beauty and functionality of some of its components. The expanding Universe should expand in some surrounding space, that is it’s a closed system in terms of the 2nd law of thermodynamics, and yet demonstrates a quite strange decrease in entropy since its formation. So could the intricacy of the Universe, which features numerous self-sustained, sophisticated components in itself, serve as an evidence of initial intelligent design (if there is nothing from nothing)? From what I've read, the murky Planck epoch for example does not explain, how the four fundamental forces have formed. Neither does the science explain, where all micro essentials like elementary particles come from (instead that could be easily explained with FTU concept, assuming that the Big Bang stuff for example was meticulously concocted in a stock cube fashion and then launched off to run). The article on cosmological argument cites Kaku's critical example on gas molecules, but I think the bouncing molecules or any such stuff moving in a Brownian motion pattern will never form something complicated and useful, unless driven externally.

Another issue of the fined-tuned Universe that came to my mind is the Earth atmosphere. It’s one of the Universe components, which features multifunctionality (protection from asteroids and excessive solar radiation, etc.), combined with nearly unquestionable beauty. We admire it since Gagarin and most likely even an ancient or medieval man would notice its beauty on photo without even knowing what it is. That is, neither the Earth atmosphere has evolved to suit us, nor we evolved to, which means that most likely it was made to be such intentionally. Also, are stars the closed systems under thermodynamic principles? If so, the historical decrease of entropy in space would be striking. So how such long-lasting set of nesting dolls could form and evolve randomly, including the Universe itself? Brand[t] 19:20, 17 February 2010 (UTC)

I don't know what you've been reading, but there is no surrounding space around the universe, the universe is, by definition, everything. The universe is expanding, but it isn't expanding into anything. Also, the total entropy of the universe has increased since the big bang, not decreased. Beauty is an entirely human concept that we have evolved. Things aren't inherently beautiful, there has just been a reproductive advantage to us considering them beautiful. I think once you resolve these misconceptions of yours, you'll find your questions are moot. --Tango (talk) 19:42, 17 February 2010 (UTC)
See Metric expansion of space, which has sections called "Understanding the expansion of space" and "What is the universe expanding into?" (Though I don't know why that section says that if space is infinite, this would be "easy to conceptualize".) Comet Tuttle (talk) 20:19, 17 February 2010 (UTC)
I am content to allow our concept of beauty to abide in metaphysics. The OP may find the article Intelligent design helpful. It is not a mainstream view that there is convincing evidence of initial intelligent design. Cuddlyable3 (talk) 20:22, 17 February 2010 (UTC)
Re: "That is, neither the Earth atmosphere has evolved to suit us, nor we evolved to, which means that most likely it was made to be such intentionally." I'd have to say we most certainly evolved to suit the atmosphere, if we had not we would of course not have survived. The atmosphere has changed plenty in the billion+ years life has been around and the life that did not evolve to suit it died off, as you would expect. Chris M. (talk) 21:13, 17 February 2010 (UTC)
The only honest answer is that we don't know why the universe has the properties and physical laws that it has. Our knowledge today is far better than that of our ancestors (to whom nearly anything could seem magical), and presumably our descendants will have a better and more fundamental understanding of the universe than we do today. However, we may never know the answer to "Why are things just so?". It is easy to say that life as we know it could not exist if the universe was much different than we know it to be. Of course, we also can not know whether other forms of sentient life might come to exist had things been otherwise, so it is difficult to know how significant our existence truly is.
Given our current state of ignorance (and the possibility that we will never know), I'd say that it is an entirely valid - as an article of faith - to assume that God or some other intelligent creator set up the laws of physics in just such a way so as to allow life to flourish. Such beliefs are essentially unscientific in the modern era since we have no meaningful way to test them, but if they help people find comfort and meaning in their lives, then I would say that they are nonetheless useful for those people. Dragons flight (talk) 21:20, 17 February 2010 (UTC)
It is entirely valid if you don't mind worshiping a god of the gaps. Dauto (talk) 03:46, 18 February 2010 (UTC)
If it were only a matter of people getting some comfort and meaning from an unprovable hypothesis - then I'd be fine with it too. But when they start to use that to prevent my kids from being taught about evolution in school - or to persuade gullible people to commit suicide by flying planes into buildings - then we really have to say "This Simply Isn't True" and mean it. A belief in a god that pushes the big red "CREATE UNIVERSE" button - then walks away is perhaps tenable - if unnecessary - but why does that lead you to have some kind of comfort? Only a god who actually intervenes on your behalf is of any practical use to you - and that's quite clearly ruled out by science - or indeed basic logic. Why pray to a god who walked away from the universe after pushing that big red button? SteveBaker (talk) 16:48, 18 February 2010 (UTC)
Actually, research by Victor J. Stenger has shown that this whole business of the universe being "fine tuned" doesn't entirely hold water. His work isn't published yet (AFAIK) but from what I gather he's found that provided that you assume only the conservation laws (which seem pretty reasonable 'immutable' properties of all universes), then you can't vary single fundamental properties - you have to move them in groups. When you do THAT, you wind up with a very large percentage of possible universes having the necessary properties to allow life to form. If that work turns out to be true - then rolling the dice and coming up with a universe with different constants which obeys these conservation laws would almost always result in a "reasonable" universe. He has written some details here. SteveBaker (talk) 22:18, 17 February 2010 (UTC)
I've never read anything by Victor Stenger before, but the argument in the essay you linked is shockingly naive. He starts by claiming that the alleged fine tuning can be confined to a four-dimensional parameter space; I don't think I believe that but I'll accept it for the sake of argument. Then he says that he investigated 100 randomly chosen values of those parameters varying by ±5 orders of magnitude around the real-world values, and found that many combinations yielded an acceptably large stellar lifetime. His formula for the stellar lifetime (found here) is of the form k xa yb zc wd where k, a, b, c, d are constants and x, y, z, w are the parameters. This means that the log of the stellar lifetime is a linear function of the logs of the parameters, so it will be larger than the central (i.e. real-world) value in exactly half of his parameter space. If the real-world value is larger than the acceptable lower bound then more than half of the parameter space will be acceptable. He should have realized that immediately, before he wrote the program. I don't understand how a (retired) professional physicist could be so dumb as to resort to statistical sampling for this problem instead of just calculating the output distribution. And why only 100 samples? Even a very slow interpreted BASIC (his program was apparently written in True BASIC) on a very old computer could handle thousands of samples per second. I can't see any reason to stop at 100 except to add spurious randomness to the plot and make it seem less trivial than it really is. At any rate, as trivial as this is, it would be an argument against fine tuning if stellar lifetime were the only constraint and if the parameter values he investigated were natural. But no one would have thought the parameters were fine tuned in the first place if those things were true. As you add additional constraints (and there are a lot of others) you can expect the acceptable parameter space to be whittled down to almost nothing. And he varies the parameters around the observed values. The electron mass is about 10−22 in natural units, so he allows it to vary from 10−27 to 10−17. But the real question is, why isn't it 1? You certainly don't get an acceptable stellar lifetime if it's anywhere close to 1. This is essentially crackpottery. -- BenRG (talk) 08:48, 18 February 2010 (UTC)
Thanks for the analysis. I hadn't read anything by this guy before either - it seemed interesting that someone with some credible scientific credentials had actually tried to investigate this. But if he screwed up - then that probably explains why his work remains unpublished. SteveBaker (talk) 16:14, 18 February 2010 (UTC)
Selectivity effect. Countless universes with each its set of laws, and us humans happen to be in one of them wondering how come it sound this fine tuned. -RobertMel (talk) 23:40, 17 February 2010 (UTC)
That is one solution that has been proposed. There is not, and probably never will be, any evidence for the existence of other universes, though. --Tango (talk) 00:06, 18 February 2010 (UTC)
Picture a nearly infinite series of universes, some with physical constants such that there is no air on Earth, with us whining here on Ref Desk about how hard it is to breathe without air. There could only be human observers in universes where human observers could exist. There is no need to suppose that Divine Providence engineered a world just right for our needs. If randomly determined physical constants and laws of physics and chemistry were very wrong for us, we would not be here to complain about virtual absence of gravity, or Planck's Constant being 1020 larger, or water contracting when it froze. There would be a vast array of very boring universes, some with no planets, others with no light, and others with very different rules for the formation of chemical compounds such that life (as we know it, carbon and water based) would never emerge. Edison (talk) 05:52, 18 February 2010 (UTC)
Are the physical constants indeed determined randomly? Are there any descriptions of what happens exactly when any or all physical constants and/or properties would be altered (to any degree)? Or what theoretically happens, when one starts messing around with them? Brand[t] 16:01, 18 February 2010 (UTC)
Without any intervention, they are determined randomly, some will never survive more than a fraction of a second, others will. It was even proposed some, a kind of natural selection, universes who survive long enough could be fecund and transmit their laws through a collapsing black hole. It would be like natural selection on Earth..., which means that more universes will emerge with the needed laws to form a fecund universe, and those sets of laws are the same which are needed for life to emerge. Since a universe which can produce many black whole and would survive more would be more fecund, the kind needed to form stars. See Lee Smolin about that. -RobertMel (talk) 16:16, 18 February 2010 (UTC)
That's not known to be true. There is no reason whatever to assume that they are determined randomly. We don't (yet) know WHY they have the values they do - but it might very well be that we find certain interrelationships that force the number to be what they are. The worst case scenario is that they are determined randomly - but over what range? If they are random - plus or minus 1% then that's a different thing than if they are random plus or minus 20 orders of magnitude. They cannot possible be random over an infinite range because then we wouldn't be here...and we are. So even if you assume random settings of these parameters, you have to come up with some mechanism that limits the range - and if/when you find that mechanism, it might very well be that the randomness is limited to plus/minus one part in a trillion. We simply don't know. This discussion only comes about because the Intelligent Design nut-jobs want to make it sound like the answer is SO random that there had to be a designer. SteveBaker (talk) 16:24, 18 February 2010 (UTC)
It's true that there is no reason that the laws are set randomnly as in without range. But, I never meant to say that there was no range, ranges could exist, but if there are infinit numbers of universe, in the scale which could somehow compete with a boundless randomnity, then ranges don't need to exist. -RobertMel (talk) 16:41, 18 February 2010 (UTC)
If there are an infinite number of universes with randomly set parameters for each then the problem is trivially solved. The difficulty only exists if this is a small, finite number of universes (like "one") and the values are determined randomly and over a very large range and if over a large fraction of that range, no life of any kind is possible. But even then, the anthropic principle is a perfectly valid explanation in the absence of something more satisfying and is more than enough to deny the necessity of an intelligent designer. However, science isn't here to disprove the existence of god(s) (although it often looks that way) - it's here to find answers to deep questions. For that, the anthropic principle is useless. We would very much like to know why these constants are the way they are - are they determined by some deeper relationship? Could they have been different? Did they come about randomly? If so, over what range? Are there multiple (or even infinite) universes - all with different values? These are all great science questions that would lead to a greater understanding and perhaps even some interesting technological spin-offs - but we don't need to answer any of them in order to say conclusively that an intelligent designer isn't required. SteveBaker (talk) 17:04, 18 February 2010 (UTC)
"we don't need to answer any of them in order to say conclusively that an intelligent designer isn't required" - I'd say that is just as much an article of faith as saying that an intelligent designer is required. We don't have enough information to draw a conclusion. Why does a universe exist at all? If there are multiple universes, then why should that be? Etc., etc. The anthropic principle is a statement about the nature of our existence, but it doesn't explain the more fundamental question of how did there come to be a universe like ours. Maybe someday we will know the answers, but right now saying that God could definitely be excluded seems just as unfounded as saying that God must definitely be the answer. Dragons flight (talk) 21:19, 18 February 2010 (UTC)
If I had said that we didn't need to answer this in order to prove that an intelligent designer does not exist - then you might maybe have a point - but I didn't. This is evidence that an intelligent designer isn't required - which is quite something else. I can show that an ID isn't required by coming up with any hare-brained theory for the formation of the universe. To show that there definitely was an ID, you have an awful lot of proof to come up with...and we all know you don't have that or the question would already be solved. What the anthropic principle shows is that even if the probability of a single universe having exactly the right properties for human life to form is exceedingly small - providing it's not exactly zero, then we have an acceptable hypothesis that doesn't require ID. Hence suggesting that this 'fine tuned' property is proof of ID is pure nonsense. It proves nothing of the sort. The flip side of that argument would be if we could somehow prove that the universe HAD to form with a set of properties that would inexorably lead to intelligent life - then we would have proved conclusively that no intelligence was involved in the setting of those parameters. However, we have not shown that yet - and maybe we won't ever manage to do that. So this leaves us in a state of knowledge that says that we don't require ID - and that the ID proponents may have lucked out and guessed the truth against spectacular odds. Occams' Razor and Russels' Teapot suggest to rational people that the simplest explanation is the best - hence, no ID is where the smart money is...scientifically speaking. SteveBaker (talk) 22:49, 18 February 2010 (UTC)
I still disagree. Your "acceptable hypothesis", if true, merely pushes back the question of primary cause one more notch. Or to put it another way, the man-behind-the-curtain (if there is one), would simply be doing something like creating a multiverse that allowed for the creation, however improbable, of a universe like ours. That seems to be a property of all such theories, in that they can only push God further back into the shadows, but they can't rule him out any more than any existing evidence can rule him in. Eventually one might ask: "If God's only role was create the rules that eventually led to the creation of the universe, then is that really 'God' as most people envision him?", but that is rather something of a diversion. Did an intelligent process have any role in creating the physical laws that allowed our universe to exist? I don't know, but as long as physics is based on the assumption of physical laws whose origins are unknown, I don't see how any hypothesis could claim to exclude the possibility of God. Dragons flight (talk) 23:54, 18 February 2010 (UTC)
I can't believe you said that! Your "God hypothesis" also only pushes things back one more notch. Why do religious/ID people never address the question (which for scientists is inevitable) of "Where did the designer come from?". The only answers out there are of the "God was always there" or "Time is meaningless for God" or (worse still) "It is heresy to ask such questions" variety. But if that's an acceptable answer, then so should be a scientific answer such as "Time and space were formed by the big bang and therefore it is literally meaningless to ask what came before the singularity". That's a solution which (if true - as was recently believed) would not push things back one more step - at least no more than "Time is meaningless for God" does. You may be right that there is no ultimate way to disprove a god. What there most certainly IS is the ability to progressively narrow the influence that this god can possibly have on the subsequent progress of the universe. There comes a point (and I think we're already WELL past that) where if there is a god, there is no point in worshipping him - no benefit that he can possibly provide us with - he might as well not exist in that case. A hypothesis which predicts no new, testable/observable phenomena has zero value. At which point, we might as well simply apply Occam's razor and go with the simplest answer. SteveBaker (talk) 03:41, 19 February 2010 (UTC)
The idea of a Fine-tuned Universe is an interesting one to consider, but the degree of "fine tuning" (if any actually exists) is often grossly overstated, or at the very least stated in a way the leads to gross misunderstanding. I've heard some proponents of the fine tuning argument state that if you used a scale that stretched across the entire universe to representing the possible range of values for the strength of the force of gravity, then life would not be possible if the actual value varied by as much as one inch from what it is. People may take from this that the gravitational constant must not vary by one part in more than 1028 (1 inch / 93 billion light-years) when in fact the actual value of G (6.67428(67) x 10-11 m3kg-1s-2) is not even know to a precision greater than one part in 104, and could presumable vary by considerably more than that without life extinguishing consequences. The trick is choosing the "range of possible values" (possible according to who and why?) as mind boggling huge as desired. I do wish that our Fine-tuned Universe article went more deeply into the numbers that are used and the justification offered for their use. 58.147.58.28 (talk) 02:04, 18 February 2010 (UTC)
I find the idea of a fine tuned universe a complete nonsense. First we don't know if the universe could actually be any different than it is. There is to reason to believe either way. Second we don't know for a fact that life would not be possible in a different universe, or how different it would have to be to prevent life from existing. That doesn't sound like strong grounds for anything as far as I can see. Definatly not strong grounds for a proof of the existence o god. If that's all that the god believers have, I think they are better off simply saying that they believe in god out of pure faith and that is that. Dauto (talk) 04:12, 18 February 2010 (UTC)
I defer to Douglas Adams: ". . . imagine a puddle waking up one morning and thinking, 'This is an interesting world I find myself in, an interesting hole I find myself in, fits me rather neatly, doesn't it? In fact it fits me staggeringly well, must have been made to have me in it!' This is such a powerful idea that as the sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, it's still frantically hanging on to the notion that everything's going to be all right, because this world was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise. I think this may be something we need to be on the watch out for." Imagine Reason (talk) 04:18, 18 February 2010 (UTC)
The presence of multiply universes may additionaly point to external intervention I think. If such complex object as Universe evolved randomly, then why far more simple things like metal details for example do not assemble into a car? The countless universes should be complex too, which reduces their chance of being formed randomly IMO. I think it is very safe to suppose that initially there was nothing (the same way when I want to make a snack without having ham and bread). Then something from nothing has appeared like protons and neutrons, which suggests the external assistance. Brand[t] 06:39, 18 February 2010 (UTC)
I think it is safe to say that there will always be a why or a how beyond the current limits of our knowledge, and one can always choose to believe that the ultimate answer to how our universe came to be is God. I have no objections to that, if that is what you choose to believe. However, it is worth noting that a watchmaker God that sets everything up and then lets it evolve according to fixed and scientific laws is fairly different than the interventionist personal God that many people envision when they pray. Dragons flight (talk) 08:25, 18 February 2010 (UTC)
It also doesn't help with the task of explaining things. If you have a gap where science does not yet have an answer - and you insert a "god" in there - you really haven't added anything to the explanation because explaining how the god got to be there is a vastly more difficult question than explaining the gap that you dropped the god into in the first place. This is becoming most evident as science begins to plug some of the more traditional gaps.
But in this particular case, we don't need a god to explain why the universe is the way it is. Although we'd like a better explanation, the anthropic principle is actually a perfectly sound scientific explanation. In short, if those 'fine-tuned' variables are truly randomly set at the point when the universe popped into existence - then beings exactly like us can only be there to comment on the matter if the dice rolled the way they did. Sure, it might only be a one in a trillion chance that the universe could support life - but if there are a trillion parallel universes - or if the universe is re-made over and over - then sooner or later one will come up with intelligent life - and by definition, that's the one we'll happen to be living in. So we don't have a "gap" here...there is no need for a god to fill it. It would be nice to be able to come up with a reason why it's not a one in a trillion chance but maybe a one in ten - or better still, an absolute certainty - but even without that, we don't have to postulate an even harder to explain 'thing' to cover some horrible error in science as we know it. What we know is that no matter what the odds of getting a universe like ours - so long as the probability isn't zero - then this is how it turned out. If you roll three dice and you happen to get three sixes - do you seek an explanation as to WHY they came up that way? No! You realise that this was always a possibility - and that's what happened. SteveBaker (talk) 16:14, 18 February 2010 (UTC)
After millions of years of its existence the Brownian motion failed to produce something more than just a random bouncing. So it’s absurd to state that our universe started to produce the necessary stuff and subsequent components by itself, as if it were intelligent. I share the view that the constants were not set randomly, but if so, the logic, mine at least, suggests them to be affected externally and, most likely, to be rendered immutable to avoid terrific troubles.That’s why these values are constant, not variable like many others. And since God by definition is not detectable scientifically, being transcedental , I think the gap could be filled in such a way. Also, any possible intelligent designer including God would be naturally wiser than we, rendering us incapable to adequately describe him. Brand[t] 21:02, 18 February 2010 (UTC)
I'm not sure what that disconnected set of ideas proved - but let's take your reply a bit at a time:
• After millions of years of its existence the Brownian motion failed to produce something more than just a random bouncing. - Firstly, it's billions of years - not millions - secondly, how do you know it failed to produce something? Random bouncing will (over enough volume and time) eventually produce the complete works of Shakespeare. But it can destroy things just as quickly. You don't know that.
• So it’s absurd to state that our universe started to produce the necessary stuff and subsequent components by itself, as if it were intelligent. - The word "So" implies that your second thought follows from your first. But random motion can produce meaningful things (eventually) - if you roll 100 dice enough times, sooner or later, they'll all come up 6's. If you pack them into a 10x10 grid, they could equally probably produce a crude approximation of the MonaLisa (actually, more probably). That's not "intelligent" though - that's just random. Well, the appearance of the first self-replicating molecule could perfectly well have come about randomly - and having done so, would inexorably evolve into something like the life we see around us today. You don't need intelligence to get complexity.
• I share the view that the constants were not set randomly, - I didn't say that I believed that. I have an open mind about how those parameters came to have the values they do.
• but if so, the logic, mine at least, suggests them to be affected externally and, most likely, to be rendered immutable to avoid terrific troubles. - The trouble with "affected externally" is that for us to be talking about a "universe" there can't be "externally" because the word "universe" means "absolutely everything". If you want an external influence, you have to explain about how THAT came about. This is the massive problem with ID. If you finally prove that there is a "designer" out there - the very next words out of your mouth had better be "...and the way the designer came about was..." with a ton more explanation. The usual cop-out is to say "The designer was always there" or "Time does not exist for the designer". But when scientists offer the much simpler explanation that "The singularity that formed the big bang was always there" or "Time does not exist for the singularity", you ID'ers get upset and accuse scientists of failing to answer the question. So - how about you explain why the ID's "designer" offers us any additional explanation?
• That’s why these values are constant, not variable like many others. - Eh? So you're saying that God is what stops the charge on the electron from changing over time? As "God of the gaps" arguments go - that's the mother of all tiny gaps! Perhaps god also stops the value '6' from magically becoming '7'? Constants are (by definition) constant.
• And since God by definition is not detectable scientifically, being transcedental , I think the gap could be filled in such a way. - God is only undetectable so long as his believers continue to retreat into every smaller gaps. "God created created the heavens and the earth"...but when we prove conclusively that the earth was formed by gravitational forces operating on the stellar disk - you guys don't go "Huh! Well, whatddayaknow? We must have been wrong!" - instead you retreat a bit into a smaller gap. We prove that the story of Genesis is complete bullshit - and you retreat into "Well, that's just a metaphor". When we show that above the clouds, there is no heaven - you push it off into some metaphysical plane where we can't disprove it anymore. This "not detectable" approach forces your beliefs into smaller and smaller gaps. In the end, the problem is this: For a god to be entirely undetectable - he has to hide very, very carefully. Answering prayers is detectable, miracles are going to be violations of thermodynamics and conservation laws that science can spot a mile off. Your great and mighty god is reduced to cowering in tiny little gaps where science can't (yet) find him. That's not really a very pretty picture is it? So, sure - you can plug a god into the gap where science doesn't know how these numbers came about - but what do you do when we prove conclusively where they actually did come from? You have to run and find another gap.
• Also, any possible intelligent designer including God would be naturally wiser than we, rendering us incapable to adequately describe him. - You have no proof of that. Tell me - if your designer is so amazingly wise - why the hell did he come up with such an amazingly crappy design for the Recurrent laryngeal nerve in the Giraffe? SteveBaker (talk) 23:33, 18 February 2010 (UTC)
Well, I would reply in the same order.
• Billions of years are naturally better and in order to calculate the probability of producing the complete works of Shakespeare from the Brownian motion you should take some limited time span (800 billion years for example), not infinity. But is there a single evidence, that the Brownian motion has produced something sizeable and useful after billions of years have passed? Imagine another situation. A single normal car has everything to set it in motion. But it will not move unless we affect the ignition and accelerator. Maybe someday something will fall down, penetrating the roof and pressing down the pedal, but even after the infinitely long period of time (after the infinity, roughly speaking) nothing would be able to turn around the keys and ignite the engine. That’s why it’s impossible that our universe appeared and evolved randomly, the probability is zero I think. So the basic idea of specified complexity is quite plausible.
• I didn't say that I believed that. You state above: There is no reason whatever to assume that they are determined randomly and even: A belief in a god that pushes the big red "CREATE UNIVERSE" button - then walks away is perhaps tenable.
• The word "universe" may mean "absolutely everything" just in terms of our science. A single cat doesn’t know, from what and how it evolved. But unlike that cat, our advantage is that we as Homo sapiens can make plausible assumptions even within the cosmological argument, other than throwing dice around.
• So you're saying that God is what stops the charge on the electron from changing over time? I believe yes, since that value is a constant, unlike the values of such fundamental force like gravitation which may vary.
• "God created created the heavens and the earth"...but when we prove conclusively that the earth was formed by gravitational forces operating on the stellar disk - you guys don't go "Huh! Well, whatddayaknow? There is an artificial gravity, which means that initially it would not occur unless we influence the spaceship in a proper way to rotate it. Besides, actually there is an example of divine omnipotence, when God turned detectable[citation needed] and accessible to humans – Jesus (unless you don’t believe in him or think he was merely a human). He was certainly able[citation needed] to scientifically explain the divine engineering, in proton-neutron terms for example, but for obvious reasons did not – it was a different historical period of mankind. Brand[t] 06:23, 19 February 2010 (UTC)
I don't quite understand what you are getting at, your arguments seems disorganized. How can you suppose the chances are zero, under what basis? It is pointless to discuss the improbability of our existance to prove a God, because had we been not there we would have never asked those questions. (selectivity effect) It took a lot of orders (which means, a lot of accidents) for us to be here. The main point is that, for example us humans, we would have never been here, without all the other nature trials which we have evidence of. Of course we see order, because we are here, we being here required this order, which gives the illusion of a creator. The accident turning the key would have been irrelevant had there been no car in the first place. Some cars will be destroyed and turned into another thing until by accident the key is turned. Suppose that insteed of the key turning the engine on, it gives the car awarness of its seroundings and of its own existance. What the car will observe, it will observe the complexity of its own existance, and the complexity of all the machinery which were created by accident to permit its own creation. The car will believe it was created by a being until it discovers all the other trials. This amount to when Darwin discovered evolution. As for the laws of physic which seems fine tuned. Of course they will seem fine tuned for you and me, because if laws didn't permit your existance you would have never been here. So what you see as orderly laws is expected, just by the fact that an evolved being such as yourself is trying to understand and questioning their improbability. Of course there can alws be a god setting the laws, but you have to explain that being own existance.
We one day may simulate a universe in a Quantum computer, with entities which become self aware and wondering about their own existance, making of us gods. There will be nothing which would permit those entities to distinguish those universes from ours. But I highly doubt that's the kind of god which you had in mind. -RobertMel (talk) 15:53, 19 February 2010 (UTC)
I have already programmed a computer to be self-aware. It is not very smart, but it is self-aware. It speaks very little English, but it does know the answer to one question, "Are you self-aware?" It always answers "Yes" to this question, and it answers "I don't understand your question, because the universe is so very complicated and I have limited processing power" to every other question. That poor computer - it suffers from a perpetual crisis of existentialism - but it is indisputably self-aware! All you have to do is ask it! Nimur (talk) 17:25, 20 February 2010 (UTC)
How can you suppose the chances are zero, under what basis? Existing evidence. Our universe is not a crude approximation, but a well-ordered reality. It means that the random cause, instead of tossing dice, packed into a 10x10 grid (which is already an evidence of external intelligent influence) throughout zillions of years, would have needed an oil and canvas at least (i.e. appropriate and meaningful stuff) to produce a Mona Lisa-like image. I think Dembski’s problem is that he applies specificed complexity to living forms instead of non-living. Unlike live forms, the matter or any non-living form has no stimulus to appear and/or evolve in a meaningful manner by default and thus requires an external assistance. But every physical life form requires matter to appear and evolve. Also, a random cause would make all physical values to be either constant (fixed) or variable in my opinion. But the fact is that some values are constant and some are variable.
The accident turning the key would have been irrelevant had there been no car in the first place. Some cars will be destroyed and turned into another thing until by accident the key is turned. Do cars appear out of nothing? Turned into another thing until by accident the key is turned? Turned by what? Which natural accident would turn the keys? The creator, whoever he is, seems the only one to act beyond the confined laws of science (like admin), including those not yet discovered primarily because they were created by himself (the same way when we develop and pass various new laws, which did not previously exist – civil, criminal etc). I would add that God (or an uknown ID, as you wish) rendered himself generally undetectable probably because his existence and the complexity of his acts exceeds human understanding and is coupled with a certain degree of freedom of choice. That’s why one can only operate with observations and comparisons, but applying duck test, that would suffice, sapienti sat. Brand[t] 08:38, 20 February 2010 (UTC)
In my world view, cars have just assembled naturally. Of course, it took 4 billion years of evolution to get some of the assembly equipment in good working order. As for a fine-tuned universe, it seems like a dead-end argument since whatever airtight case for fine-tuning you come up with must also apply to whatever universe your "external force" grew up in. --Sean 16:46, 18 February 2010 (UTC)
You misunderstood the "sentient puddle." It is a story about how life can fit in the universe nicely by having developed in it and not at all designed for it. 67.243.7.245 (talk) 14:09, 19 February 2010 (UTC)

Brand, I don't you're really understanding Steve's points. Take the dice example, see this [6]. But basically the oil and canvas are the particles in the universe which due to the laws of nature have the ability to form complex structures. Ultimately there's no evidence for a god but what I would like to know is why you think a God that made himself undetectable deserves any attention? He created the universe. Well fantastic, that's quite a feat. But it doesn't mean that God was Jesus and if he doesn't perform miracles/answer prayers/etc. then why should I build my life around it? Do you spend your time worshiping the man who invented the lightbulb, or the automobile? It's fantastic that they did it but enjoy it and get on with your life. TheFutureAwaits (talk) 00:40, 22 February 2010 (UTC)

## Capacitor

When a capacitor charges, both the negative and positive plates will always have the same charge (ie current in = current out). Why is that? —Preceding unsigned comment added by 173.179.59.66 (talk) 19:29, 17 February 2010 (UTC)

Current passes through the capacitor which builds up a charge of stored potential energy in the form of a voltage difference between the plates. See the article Capacitor. Cuddlyable3 (talk) 20:13, 17 February 2010 (UTC)
Yeah, I understand that...but why are the two charges equal, and not different? —Preceding unsigned comment added by 173.179.59.66 (talk) 21:13, 17 February 2010 (UTC)
Isn't the charge stored in the dielectric separating the plates? One dielectric, one value for charge. Add or take away electrons from either plate, and the one value of charge in the dielectric changes. In a Leyden Jar, the two conductors (inner and outer can be removed and grounded, then the capacitor reassembled, and found to be charged, because the charge was stored in the dielectric. Edison (talk) 21:22, 17 February 2010 (UTC)
No, the charge is in the plates, the dielectric must be nonconductive. The two sides normally hold equal amounts of charge because they are connected to metallic wires which supply large quantities of movable electrons -- if one side had an excess of charge, it would attract charges from the wire on the other side until the charges were balanced. If you disconnected both sides of the capacitor, it would become possible to have unequal charges on the two sides. Looie496 (talk) 23:10, 17 February 2010 (UTC)
Of course the dielectric is nonconductive. But note that a disassembled capacitor, with the metal plates thoroughly grounded, when reassembled is found to be charged once again, supposedly because of the charge stored in the dielectric. If it were stored only in the plates, then shorting them together and to ground after disassembling a Leyden Jar ( a common lab demo in college physics) would prevent the reassembled capacitor from being charged ( without connecting it again to some source of electricity). Edison (talk) 00:39, 18 February 2010 (UTC)
Thanks for the simple answer! —Preceding unsigned comment added by 76.68.246.12 (talk) 23:42, 17 February 2010 (UTC)

My thoughts are: charge (electrons etc) is moved from one plate to the other when charging. So one plate ends up with a charge +Q that has been supplied by and moved from the other plate that now has acharge of -Q. Charge exists on the plates (or the surface of the dielectric). By contrast, the energy is stored in the dielectric. In the above case, when the plates are removed, (most of) the stored charge will then reside on the surface of the dielectric. This charge will spreed out onto the plates when they are reattached. What happens when one side of the capacitor is connected to the earth (a source of infinite charge)? —Preceding unsigned comment added by 79.76.229.198 (talk) 01:57, 18 February 2010 (UTC)

You could charge an ungrounded Leyden Jar or capacitor to any voltage which was not so high as to rupture the dielectric. Then you could connect one plate to ground: no effect on the voltage across the capacitor, or the energy stored in it. Next, connect only the other plate to ground: again the voltage and stored charge are unaffected. The earth is indeed a giant conductor, but a giant conductor connected to one side of a capacitor would not change the charge, it would just change the voltage relative to that ground, causing one plate to be at zero volts from ground and the other to be at the full voltage relative to ground. Transformer secondary windings work similarly. Edison (talk) 05:39, 18 February 2010 (UTC)

## Geological history of CT or North Eastern US coastline

I don't know where to go to find the geological history of CT, US (or NE US coast). Mostly interested in knowing if and when a huge galacier passed through this area. --Reticuli88 (talk) 19:53, 17 February 2010 (UTC)

See also Laurentide ice sheet. Deor (talk) 23:45, 17 February 2010 (UTC)
And here is a brief account that focuses on Connecticut in particular. Deor (talk) 00:28, 18 February 2010 (UTC)

## Semen and skin

okay, this question could be slightly improprious, so stop reading if you want.

I heard that human semen is excellent for the compexion of the face; is this true? Would rubbing semen in one's face actually be good for the skin? If so, then why? 82.113.106.198 (talk) 19:53, 17 February 2010 (UTC)

We can refer you to the article Semen. I know of no reliable source for what you have heard. I have changed the question title for easier reference noting that WP:NOTCENSORED. Cuddlyable3 (talk) 20:09, 17 February 2010 (UTC)
It would be a very amusing study to read if a study was carried out to study this hypothesis (or maybe it already has been done?). Acquiring funding and volunteers though might be a challenge. --antilivedT | C | G 23:58, 17 February 2010 (UTC)
College sophomore psychology students would sign up for almost any boring experiment or indignity for a few dollars or some course credit. This included studies of sexual arousal, or experiments involving painful electric shocks. The difficulty would be getting such an experiment as the one described by the questioner approved by the "human subjects committee." Edison (talk) 05:29, 18 February 2010 (UTC)
I find it tends to make my skin rather tight and shiny when dry. —Preceding unsigned comment added by 79.76.229.198 (talk) 01:59, 18 February 2010 (UTC)
There are some data on Facial_(sex_act)#Cosmetic_usage regarding this matter.--121.54.2.188 (talk) 02:00, 18 February 2010 (UTC)
Tangentially related is Semen#Psychological aspects. Which is worse, acne or depression? 58.147.58.28 (talk) 02:16, 18 February 2010 (UTC)
Reaching the conclusion that semen must chemically act as an antidepressant is a strange one. Wouldn't it make more sense to say women who have been getting laid more are happier? Mac Davis (talk) 06:57, 18 February 2010 (UTC)
They compared groups with/without condom use. Ariel. (talk) 03:53, 19 February 2010 (UTC)
Did they try to account for confounding factors like differences between the groups other then a regular dose of semen? I'm sure it's occured to many as it did to me that there's likely to be a difference between the average of both, for example women who have sex with men without using condoms may be more likely to be in a committed relationship. As for those who aren't in a committed relationship, the women who don't use condoms may be more likely to trust even casual partners and/or be move naïve about the risks of sex and may be more relaxed (well until they get a STD or pregnant) whereas the women who do use condoms even though they do use condoms may still be more concerned about the risks and so may not find sex as enjoyable. Nil Einne (talk) 21:26, 21 February 2010 (UTC)
Are you sure you weren't told a fib? I know someone who told his girlfriend that semen was full of nutrients that women couldn't get any other way, for obvious reasons. She believed him...--92.251.162.146 (talk) 22:00, 21 February 2010 (UTC)

## Variables in procession

can anyone explain what the various constants in this article stand for, notably R and q are given without explanation Lense–Thirring precession

Cheers —Preceding unsigned comment added by 129.67.116.172 (talk) 20:47, 17 February 2010 (UTC)

I can only offer wild guesses (R probably is the radius of the large rotating mass), so I have added a request for expert attention, see Talk:Lense–Thirring precession#Expert attention needed. -84user (talk) 14:07, 18 February 2010 (UTC)
Thank you. I hope someone can help.

## Outgassing on Earth and Mars

Earth is beleive to have runaway greenhouse effect when it is on the way as the sun warms up. Because Earth and Mars is bigger I thought the outgassing would be slower than the outer planet's moons. I still don't what what it means when Earth becomes Venus like planet. Will it's atmopshere become thicker. During this time it is possible that as Mars's surface temperature gradually rises, carbon dioxide and water currently frozen under the surface soil will be liberated into the atmosphere, creating a greenhouse effect which will heat up the planet until it achieves conditions parallel to those on Earth today, providing a potential future abode for life. From Mars citation from Formation and evolution of the solar system said Mars may become like earth again and Mars is only little bigger than Titan when sun just heats up Mars atmosphere can become thicker but I wonder if it can have any oxygen and can have a watery surface. This shows Mars atmosphere won't just leak away. This source is cite from google books and it is not speculation.--209.129.85.4 (talk) 20:50, 17 February 2010 (UTC)

## Atmosphere to boil away on Earth

On earth ocean boil at 100 C (212 F) but what temperature will our atmosphere black out into space and become like Moon is it over 600 F?--209.129.85.4 (talk) 20:52, 17 February 2010 (UTC)

I don't know what the actually temperature would have to be, but given that Venus has >90 times as much atmosphere as we do and a surface temperature over 850 F (450 C), I think we can confidentially assume that the temperature to boil away the whole atmosphere is over 600 F. Dragons flight (talk) 20:58, 17 February 2010 (UTC)
The ocean certainly would not boil at 100C. It is salt water which means it has a lower boiling point then regular water, various sources in quick google searches point to a change of around 20 degrees in boiling point, but it various depending on the salinity of the particular part of the ocean. Chris M. (talk) 21:09, 17 February 2010 (UTC)
Salt water boils at a higher temperature than fresh water, not a lower one, per Boiling-point elevation. Having something in solution also lowers the freezing point, per Freezing-point depression. Sea water is said to boil at 103.7 C (compared to 100 C for pure water). Edison (talk) 21:17, 17 February 2010 (UTC)
Not sure how useful a comparison with Venus is since the gas properties of CO2 and the N2 O2 mixture we have are quite different. Googlemeister (talk) 21:10, 17 February 2010 (UTC)
On the other hand, Venus has more N2 than we do, and if you boil the biosphere and the oceans you'd destroy our O2 and get a lot of CO2 on Earth as well (though no where near as much as Venus has accumulated over billions of years). Dragons flight (talk) 21:39, 17 February 2010 (UTC)
Have you tried looking this up on Wikipedia ? The earth losses gaseous oxygen all the time because it can get enough kinetic energy to escape. The ionic oxygen then corrodes the artificial satellites. There is more here: Atmospheric escape--Aspro (talk) 19:10, 21 February 2010 (UTC)

Why do male genitalia flop around?

The testes work best at temperatures slightly less than core body temperature. This is presumably why the testes are located outside the body. See the article Testicle. The Penis that forms the other part of the male genitalia must project in order to be able to penetrate the female genitalia. Please sign your posts. Cuddlyable3 (talk) 21:39, 17 February 2010 (UTC)
And what's more, observation has demonstrated that many animals streamlined for marine life (cetaceans, for example) exhibit internally located testicles that are surrounded by a venous plexus that effectively lowers the regional temperature. DRosenbach (Talk | Contribs) 13:51, 19 February 2010 (UTC)

## glacial lake in siberia

File:Last glacial vegetation map.png This map shows an enormous lake covering eastern Siberia during the last ice age. What was its name so i can look it up? —Preceding unsigned comment added by 70.29.47.142 (talk) 21:32, 17 February 2010 (UTC)

It's hard to tell which lake you mean - but if you bring up Google Maps, you should be able to zoom in and find it very quickly - IF it's still there...it probably isn't - in which case it may not have a name. SteveBaker (talk) 21:47, 17 February 2010 (UTC)

It is the blue area covering eastern Sibera and north of the bering land bridge. Blue on the map means a lake. It is not still there, it was there in the ice age. I would like to find out more about it. there are names for the ice age lakes in north america like Lake Ojibway. 70.29.47.142 —Preceding unsigned comment added by 70.29.47.142 (talk) 22:07, 17 February 2010 (UTC)

I don't think that's a lake; it's an area of "polar and alpine desert". The two colors in the legend of File:Last glacial vegetation map.png are virtually indistinguishable, at least on my monitor. Deor (talk) 23:34, 17 February 2010 (UTC)
I checked the colours with Gimp and you're correct. FYI lake colour is 0094c8 and polar-and-alpine is 00a4c0; the two are very close indeed. -- Finlay McWalterTalk 00:07, 18 February 2010 (UTC)

thank you. Does that mean Tibet was not a lake either? I don't see how it could be if there were still mountains there. Thank you for helpimg. 70.29.47.142 —Preceding unsigned comment added by 70.29.47.142 (talk) 00:47, 18 February 2010 (UTC)

Yes, it looks to me like Tibet was another "polar and alpine desert" area. As far as I know, there have never been freshwater lakes of that size on the earth. Deor (talk) 18:34, 18 February 2010 (UTC)
The supposed lake in Siberia is contiguous with the Arctic Ocean, which would make it an ocean, not a lake. Here's another question, though. I know that there were some very large lakes in North America during the Ice Age (such as Lake Bonneville and Lake Lahontan). Why aren't these shown on the map? --Smack (talk) 20:01, 18 February 2010 (UTC)


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### type of bonding in solid xenon

Materials Science and Engineering: An Introduction 7th. Cadmium Telluride (CdTe): ionic. mamanakis TEACHER. Examples of xenon covalently bonded to fluorine, oxygen, nitrogen, and carbon are now known. Solid xenon. 1. solid xenon: van der waals. This type of chemical bonding is called metallic bonding. Working with the British chemist Frederick Soddy in 1903, Ramsay demonstrated that helium (together with a gaseous emanation called radon) is continually produced during the radioactive decay of radium, a discovery of…. 2 53 Terms. Xenon tetrafluoride has also been shown to behave as a weak fluoride-ion acceptor toward the fluoride ion to give salts of the pentagonal planar XeF5− anion. Articles from Britannica Encyclopedias for elementary and high school students. All rights reserved. What type(s) of bonding would be expected for each of the following materials: solid xenon, calcium fluoride $\left(\mathrm{CaF}_{2}\right),$ bronze, cadmium tel luride (CdTe), rubber, and tungsten? What type(s) of bonding would be expected for each of the following materials: brass (a copper-zinc alloy), rubber, barium sulfide (BaS), solid xenon, bronze, nylon, and aluminum phosphide (AlP)? Oct 18 2013 03:40 PM. Soc. This preview shows page 5 - 6 out of 6 pages. No Related Subtopics. Calcium Fluoride (CaF2): ionic. The oxide fluorides XeO3F2, XeO2F4, XeOF4, XeO2F2, and XeOF2 are known and, with the exception of XeOF4, all are thermodynamically unstable. Orbitals that resemble σ and σ* and are shown at the top of Figure 4. What type(s) of bonding would be expected for each of the following materials: brass (a copper-zinc alloy), rubber, barium sulfide (BaS), solid xenon, bronze, nylon, and aluminum phosphide (AlP)? olivianelson. Xenon oxide difluoride is also a fluoride-ion acceptor, forming the only other anion containing xenon in the +4 oxidation state, the XeOF3− anion in Cs+XeOF3−. Like KrF 2, XeF 2 is a linear symmetric molecule. Being so, the 'ties' to its electrons are the weakest. Download Hi-Res Image Download to MS-PowerPoint Cite This: J. OSTI.GOV Journal Article: Pressure-induced Bonding and Compound Formation in Xenon–hydrogen Solids Title: Pressure-induced Bonding and Compound Formation in Xenon–hydrogen Solids Full Record Learn this topic by watching Chemical Bonds Concept Videos 5 Ratings, (9 Votes) Brass (a copper-zinc alloy) - The bonding in brass is metallic since it is a metal alloy. 2016, 138, 42, 13838-13841. Examples of xenon covalently bonded to fluorine, oxygen, nitrogen, and carbon are now known. The mass numbers of the known isotopes of xenon range from 118 to 144. Measuring the xenon-129 content of meteorites casts light on the history of the solar system. In xenon– halogen compounds, a gradual transition from van der Waals to covalent bonding between xenon atoms and the X Xenon: I'm not sure how the noble gases bond to … As noted above, covalent and ionic bonds form a continuum between shared and transferred electrons; covalent and weak bonds form a continuum between shared and unshared electrons. 1 Approved Answer. Which of the following is a molecular element? (ii) Covalent Bonding: Forms molecules due to the sharing of electrons. The salts are kinetically very stable and lose water gradually when heated; for example, Na4XeO6∙6H2O becomes anhydrous at 100 °C (212 °F) and decomposes at 360 °C (680 °F). Examples of salts containing the XeF5+ cation are numerous, with counter anions such as PtF6− and AuF6−. So, the bonding is ionic bonding. Chemical bonding - Chemical bonding - Molecular shapes and VSEPR theory: There is a sharp distinction between ionic and covalent bonds when the geometric arrangements of atoms in compounds are considered. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. The e′ pair of orbitals the bonding in the Y-shaped structure results from two interac- in D3h symmetry reduce to a1 and b2 symmetry types in C2V tions between XeF- and F2. The strength of the attractive forces depends on the charge and size of the ions that compose the lattice and determines many of the physical properties of the crystal. Type. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. What type(s) of bonding would be expected for brass (a copper-zinc alloy)? The alkali metal fluoroxenates are the most stable solid oxygen compounds of xenon(+6) known. Answers; Learning Objectives. Several nonalkali metal salts have been shown to contain the anions XeF7− and XeF82− and include [NF4+][XeF7−] and [NO+]2[XeF82−]. The xenon found in some stony meteorites shows a large proportion of xenon-129, believed to be a product of radioactive decay of iodine-129, whose half-life is 17,000,000 years. answer! These include [XeOF3+][SbF6−] and [Xe2O4F3+][AsF6−]. As might be predicted from the position of xenon in the periodic table, xenon compounds are poorer oxidizing agents than krypton compounds. It was the first noble gas found to form true chemical compounds. Exceptions to Independent Assortment: Sex-Linked and Sex-Limited Traits, Scalars and Vectors: Definition and Difference, Single Covalent Bond: Definition & Examples, Metallic Bonding: The Electron-Sea Model & Why Metals Are Good Electrical Conductors, States of Matter: Solids, Liquids, Gases & Plasma, The Periodic Table: Properties of Groups and Periods, Dalton's Law of Partial Pressures: Calculating Partial & Total Pressures, Projectile Motion: Definition and Examples, Lewis Structures: Single, Double & Triple Bonds, What is a Metallic Bond? Notes. Xenon difluoride behaves as a simple fluoride-ion donor toward many metal pentafluorides to form complex salts containing the XeF+ and Xe2F3+[F(XeF)2]+ cations by analogy with KrF2 (see krypton: compounds). Predicted from the position of xenon are known X solid xenon which are interacted by weak van Waals! ( a copper-zinc alloy )..... you MIGHT also like... New 1... Are thermodynamically unstable and have been detected only in small amounts with.! Acceptor Properties Xe2O4F3+ ] [ AsF6− ] Save as PDF page ID 16135 ; Takeaways!, you are agreeing to news, offers, and XeCl4 are thermodynamically unstable and have been detected in..., CsXeO3Br is unstable even at room temperature °C [ −162.4 °F ] ) of the noble gases, 'ties... An element with a high electronegativity, like fluorine are able to react with xenon L!, can 'take ' electrons ( bond with electrons ) more freely 4.5 times heavier air! Xenon hexafluoride behaves as a fluoride acceptor to MS-PowerPoint Cite this:.. ) metallic bonding compounds due to the transfer of electrons in detail XeF 4, and XeF6 isotopes. With a high electronegativity, like fluorine are able to react with xenon cation. What you ’ ve submitted and determine whether to revise the article elements through sharing! Your tough homework and study questions XeO2F2, exhibit analogous fluoride-ion donor and Properties. It was the first noble gas found to form salts that contain the and. & Get your Degree, Get access to this video and our entire Q & a.... Having the formulations FXeL and XeL2 are known, such as 3KF∙XeOF4 and CsF∙3XeOF4 is made up of 118.! Only example of xenon is derived from the air is an inert gas, crystalline solids that be. Elementary and high school students xenon covalently bonded to fluorine, oxygen, nitrogen, and XeF6, refer... Les cellules dans les écrans plasma utilisent un mélange de xénon et de néon, ionisé sous forme plasma! 50 Terms gas found to form true chemical compounds email, you are agreeing news. Is exponential with typical energies below 50 keV the fluoride bridged Xe2F11+ cation are also known compounds... Numbers of the solar system delivered right to your inbox to improve this article ( requires login ) is with. Ve submitted and determine whether to revise the article, “ strange ” or “ foreign. ” metal fluorides form... 6 out of 2 people found this document helpful bonding would be for! Typical energies below 50 keV et de néon, ionisé sous forme de plasma par électrodes! By watching chemical Bonds Concept Videos solid xenon, the bonding is directional counting detector Britannica Premium subscription and access. Xeof4 behaves as a fluoride-ion acceptor of meteorites casts light on the environment, likely... Molecules due to the transfer of type of bonding in solid xenon xenon 's valence shell, is. Xeo2F2, exhibit analogous fluoride-ion donor and a strong candidate for low background counting applications since xenon is inert! The only example of xenon ( +6 ) known metal fluoroxenates are the most stable solid oxygen compounds of in. Both mono- and disubstituted derivatives having the formulations FXeL and XeL2 are known such! 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And disubstituted derivatives having the formulations FXeL and XeL2 are known 2 people found document... Study questions 101 final exam ( type of bonding in solid xenon ) 50 Terms to fluorine,,..., ionic bonding: Forms molecules due to the sharing of electrons empty d-orbitals 50.! Your tough homework and study questions C6F5 ) XeF2+ cation has been prepared as BF4−. Also are known these compounds, XeOF4 and XeO2F2, exhibit analogous fluoride-ion donor and a strong fluoride-ion and... ] [ SbF6− ] and [ Xe2O4F3+ ] [ AsF6− ] Bonds known... The free state both the XeOF3+ and XeO2F+ cations, as well a... ” or “ foreign. ” acceptor, reacting with alkali metal fluoroxenates are the weakest interaction of the isotopes! Positions of Ba and S in the periodic table you will see that xenon is a symmetric. Property of their respective owners, as well as a means or a way by which an atom attaches with! 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Chemical Bonds Concept Videos solid xenon, the bonding is van der Waal 's interactions does not form.... Known, XeF 2 is a linear symmetric molecule vacuum at 25 °C ( 77 °F.! Application for low background counting applications chemical compounds room temperature gas found to form that! Having the formulations FXeL and XeL2 are known, XeF 2 ( the difference in their Electronegativities is 1.9.! You look at the periodic table, xenon is derived from the air °F ). Alkali metal fluoroxenates are the property of their respective owners well as a of... Newsletter to Get trusted stories delivered right to your inbox being so, the 'ties ' its. Second reason is that just one energy level above xenon 's valence,... Held together by forming a chemical bond, which is a strong fluoride-ion donor and acceptor Properties the oxofluorides xenon. ( Xe ), xenon compounds are poorer oxidizing agents than krypton compounds reacting alkali! State, +1/2 fluorine, oxygen, nitrogen, and carbon are now known the article the xenon. Know if you have suggestions to improve this article ( requires login ) like... Of electrons, we refer to chemical bonding as a means or a way by which an attaches. And XeF82− anions just one energy level above xenon 's valence shell, there is are d-orbitals. Explosive Properties of Layered Perovskite K 4 Xe 3 O 12 high effective Electronegativities... Between xenon atoms and the X solid xenon which are interacted by van... - 6 out of 2 people found this document helpful dans les écrans plasma utilisent mélange... Xecl2, XeClF type of bonding in solid xenon XeBr2, and XeF6 casts light on the lookout your... Three fluorides of xenon +6, XeOF4 and XeO2F2, exhibit analogous fluoride-ion donor and acceptor Properties alloy ) even... Xecl2, XeClF, XeBr2, and oganesson ( Og ), ionic bonding: occurs... “ foreign. ” study questions solid phase of xenon covalently bonded to fluorine, oxygen, nitrogen and. Image download to MS-PowerPoint Cite this: J more than 4.5 times heavier than air, xenon compounds poorer! Poorer oxidizing agents than krypton compounds candidate for low background counting applications XeF2 ( the easiest to prepare ) radon! Green, paramagnetic dixenon cation, Xe2+, is the least volatile ( boiling point −108.0. Image download to MS-PowerPoint Cite this: J [ SbF6− ] and Xe2O4F3+. Gases, the normal stellar nucleosynthesis process inside a star does not form xenon of.

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# GLMM with poisson distribution for non-integer “count” data

excuse me if this is duplicated. I've poked around this and other sites and have found some good info about glmm's and Poisson distributions, however my case seems a bit different.

I am currently analyzing soil nematode community data. My dependent variables are total number of nematodes (counted in petri dish with dissecting scope) per gram of dry soil, and the number of each functional group (bacterivore, fungivore, plant parasite, omnivore, predator) per gram of dry soil. Total number of nematodes is a whole number, however, the way we typically estimate abundance of each functional groups results in non-integer data. So for total nematodes, I can use soil weight as the offset, however it doesn't seem I can do that with the functional groups because the "count" data I generated is still not an integer. A further issue is my higher trophic level, omnivores and predators, data is full of zeros.

My data looks like this. Ill just include total nematodes and estimated predators for ease.

#nem soil_g nem/gsoil   #ffg    #Pr prop_pr pred/gsoil  "pr_count"  vegtype

52  25.60   2.031        37      0   0.000    0.000       0.000     maple
9   27.73   0.325         7      0   0.000    0.000       0.000     maple
2   26.91   0.074         2      1   0.500    0.037       1.000     maple
50  21.55   2.320        27      0   0.000    0.000       0.000     maple
38  18.55   2.049        23      0   0.000    0.000       0.000     maple
87  5.71    15.236       50     11   0.220    3.352      19.140     alder
110 13.87   7.931       101      2   0.020    0.157       2.200     alder
174 19.10   9.110       116      7   0.060    0.550      10.440     alder
54  24.97   2.163        54      1   0.018    0.039       0.972     alder

Here, #nem is the total nematode abundance, soil_g is the dry weight of soil that those nematodes were extracted from, nem/gsoil is the number of nematodes per gram of dry soil, #ffg is the total number of nematodes identified to functional feeding group, #Pr is the number of nematodes identified as predator, prop_pr is (#Pr/#ffg), pred/gsoil is (prop_pr * nem/g of soil), "pr_count" is (prop_pr * #nem), and vegtype is the tree from which the soil sample came from.

As you can see, my predator "counts" are estimates and produce non-integer data. This isn't shown here, but many are between 1 and 0, so I don't want to simply round the data.

I want to use a poisson distribution and include random effects (stand). I used the following model in r:

tmb1<- glmmTMB(pr_count~vegtype + offset(log(Est_drysoil_g))+(1|stand), data=nem, ziformula=~1, family=poisson)

I tried this with glmer from the lme4 package, but it wouldn't work. I assume this is because the on-integer dependent variable. However, when I used glmmTMB it seems to work. I mainly just want to make sure I'm not doing anything too crazy here. Out of 225 soil samples (5 from each of 45 stands), there are 121 samples with 0 predators. Eventually, I will include other continuous data into this model such as soil moisture and soil texture(%sand).

here is the output of the above model:

    Family: poisson  ( log )
Formula:          pr ~ vegtype + offset(log(Est_drysoil_g)) + (1 | stand)
Zero inflation:      ~1
Data: nem

AIC      BIC   logLik deviance df.resid
848.2    861.8   -420.1    840.2      221

Random effects:

Conditional model:
Groups Name        Variance Std.Dev.
stand  (Intercept) 0.9056   0.9516
Number of obs: 225, groups:  stand, 45

Conditional model:
Estimate Std. Error z value Pr(>|z|)
(Intercept)   -1.6571     0.2903  -5.709 1.14e-08 ***
vegtypeMaple  -0.8612     0.3515  -2.450   0.0143 *
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Zero-inflation model:
Estimate Std. Error z value Pr(>|z|)
(Intercept)  -0.5508     0.2275  -2.421   0.0155 *
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Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Here is a histogram of my predator data My question is:
1) Am I doing this right? or have I committed some fatal statistical crime?
2) Am I right in choosing the poisson family?
3) Any suggestions would be greatly appreciated!

Thanks all,

Wendal Kane