Wikipedia:Reference desk/Archives/Science/2011 August 5

= August 5 =

Question (acetone)
I used Acetone to clean my car windows. The fumes and vapors from the Acetone got so bad that it irritated my eyes and body. What can I do to get rid of the fumes and vapors? Thanks and hope to hear from you soon. Thanks for the answers, is there any more suggestions. — Preceding unsigned comment added by 174.111.55.161 (talk) 01:30, 5 August 2011 (UTC)


 * If that question still requires an answer, let us know. μηδείς (talk) 01:48, 5 August 2011 (UTC)


 * Roll down the windows and drive for an hour with the air blasting through the car. You might wish to read our acetone article. Looie496 (talk) 01:50, 5 August 2011 (UTC)


 * If the vapour saturation is high enough, duck and light a match. Plasmic Physics (talk) 02:02, 5 August 2011 (UTC)


 * Watch out, some idiot will try that and sue... but seriously, acetone is a small, highly volatile molecule which easily diffuses into the air and blows away.  Also, in small amounts acetone is a normal metabolite in the human body - though in diabetics it can build up to acetone breath and become part of a pathology.  So as long as you let the car air out enough that you don't smell it (assuming a normal sense of smell) it should not be a hazard at trace levels. Wnt (talk) 05:24, 5 August 2011 (UTC)


 * Can hardly sue Wikipedia for misinformation, it is a wikia afterall. Plasmic Physics (talk) 08:04, 5 August 2011 (UTC)


 * No, but they can get a court order to force Wikipedia to reveal your identity, and then they can sue you. -- Jayron  32  16:16, 5 August 2011 (UTC)


 * That would be a problem for them, my identity is not contained with Wikipedia. Plasmic Physics (talk) 19:33, 6 August 2011 (UTC)


 * Not at all. Wikipedia doesn't have a list Plasmic Physics = David Smith of 327 Magnolia Way, Cardiff completely fictional, off the top of my head, no real person or address to my knowledge, but they can access all the IP addresses you have ever used with this account. This is not easily available, nor just handed out (see WP:CHECKUSER), but they can certainly look it up and hand it over if necessary. These IP addresses will probably mostly correspond to your Internet Service Provider, who will know who was assigned which IP addresses at what time. Some addresses might be your local library, some might be other houses and places, but you can be found if someone really wants to find you. (You could make it a lot harder in some ways, though, if you could be bothered: most people don't bother unless their access to something fun is cut off without it). 82.24.248.137 (talk) 23:08, 7 August 2011 (UTC)


 * Luckily, where I live you're protected from other people's misuse of commonsense, unlike the USA. Plasmic Physics (talk) 23:35, 7 August 2011 (UTC)


 * Is using acetone to clean car windows a good idea? Seems like a great way to ruin the rubber seals and allow leaking later, or to damage the paint on the car.  Googlemeister (talk) 12:49, 5 August 2011 (UTC)


 * Agreed, bad idea. Use the blue window washer solution made for cars.  But, now that the deed is done, I suggest rinsing it thoroughly, rolling all the windows down, and letting is sit for a while.  StuRat (talk) 21:51, 5 August 2011 (UTC)

Thomisida
. Good morning everybody. This spider is surely a member of the Thomisidae family. But I'd like to know the exact species. I photographed it in July, in my garden, lower St-Lawrence region, Prov. of Quebec, Canada. Dhatier (talk • contribs) 03:21, 5 August 2011 (UTC)
 * Good morning. That is a very fine photograph. Cuddlyable3 (talk) 12:40, 5 August 2011 (UTC)
 * It's a goldenrod crab spider, Misumena vatia, the most widespread of the genus Misumena (flower crab spiders). Occurs all throughout the northern hemisphere. I have requested a rename.--  Obsidi ♠ n   Soul   16:00, 8 August 2011 (UTC)

WHAT PERCENT OF THE PLANETS IN THE GALAXY HAVE LIFE
i know it is hard to say for sure, so your best guess is fine. also, do most planets with life have aliens (sentient) or just trees and bugs and single cell organisms?--Fran Cranley (talk) 03:42, 5 August 2011 (UTC)


 * The short answer is that nobody knows. The long answer is to look at the Drake equation, fill in the necessary fields with whatever value you consider appropriate, and then admit that you don't know either. All we know is that this planet has life, and that it took a long time to evolve to its present state - so a modicum of care over the health of the planet might not be misplaced. AndyTheGrump (talk) 03:50, 5 August 2011 (UTC)


 * From what we have observed, it seems there could be 1,235 planets outside the solar system that we can detect (as of Feb 2011). There are also 8 planets in this solar system. As far as we know only 1 of them has life (but we could be wrong). So if you want to calculate a percentage based exclusively on what we have observed of the Galazy so far, it is 0.0805%. Obvioulsy there is a vast amount of unobseverd planets, so that percentage doesn't mean anything at all. --Lgriot (talk) 11:21, 5 August 2011 (UTC)


 * We don't know if any of the "observed" extrasolar planets have life ("observed" in quotes because we mostly just deduce their existence indirectly from spectrographic and brightness variations when observing their parent stars). We have found no blindingly obvious signs of life on other planets in the solar system, but we have extremely rarely even looked for signs of life at any of the known or suspected extrasolar planets. Our tools for doing that are wholly inadequate at the moment. Indeed, our inadequate observation equipment very much limits the type of planets we can detect to implausible candidates for life. Life on Earth evolved essentially as soon as the surface cooled down. This suggests that primitive life may be very frequent. On the other hand, complex life seems to have taken ~3 billion years to evolve from single-celled ancestors, and wether Earth has evolved intelligent life yet is debatable ;-). --Stephan Schulz (talk) 11:44, 5 August 2011 (UTC)


 * Where do we find anyone intelligent enough to debate that? Cuddlyable3 (talk) 12:38, 5 August 2011 (UTC)


 * I believe life must be far more prevalent than intelligent life. As noted above, life on Earth seemed to start as soon as the proper conditions existed, so I would assume this would also happen elsewhere.  However, if there were many planets with advanced technology, then we'd expect to have heard from some by now.  Perhaps there's a middle ground, with many planets containing whales and such, which are somewhat intelligent, but either not quite intelligent enough for extra-planetary communication, or simply lacking the hands, tentacles, etc., needed to do so. StuRat (talk) 21:46, 5 August 2011 (UTC)
 * What I'm a bit scared about is that the reason for the Fermi paradox may well be that technological civilisations destroy their habitat (and thus themselves) before they learn to leave it... --Stephan Schulz (talk) 23:46, 5 August 2011 (UTC)
 * Simple solution to that: don't try and learn to leave it. We'll live forever, then ;) --  KägeTorä - (影虎)  ( TALK )  14:15, 6 August 2011 (UTC)

Water flowing on Mars???


NASA is saying they see evidence of briny water flowing on present-day Mars, perhaps under the surface. How on, erm, Mars is it possible for water to be liquid when it should freeze or evaporate in the cold and thin atmosphere? Wnt (talk) 05:01, 5 August 2011 (UTC)


 * The simple answer is that the conditions under the surface must be different enough from those at the surface to circumvent the problem you describe. Dauto (talk) 06:14, 5 August 2011 (UTC)


 * Do planetary geologists predict higher pressures underground on Mars sufficient for liquid water to exist? -- 203.82.81.40 (talk) 07:39, 5 August 2011 (UTC)


 * The key is "briny". Pure water would definitely not be in a stable liquid state at the temperatures that they observe at these sites (250 to 300 K). Salt decreases the melting point of water (by up to 70K, they say) and makes it more stable. --Wrongfilter (talk) 11:28, 5 August 2011 (UTC)


 * I see someone has started a pretty nice article on seasonal flows on warm Martian slopes, which clarifies that even though the water may be only as salty as Earth's oceans, the slopes are 250 to 300 K. I hadn't realized that anywhere on Mars ever got up to such balmy temperatures!  But what still confuses me is why it doesn't evaporate instantly.  Is there some way that a relatively thin layer of soil could maintain a partial atm of pressure? Wnt (talk) 16:18, 5 August 2011 (UTC)


 * Yes, that is what I am wondering. From a Terran point of view, the atmosphere of Mars seems rather vacuous (MSL pressure of ~ 0.6% earth atmosphere. Also, where can I read abou the physical properties of brine? Wrongfilter suggests a 70K freezing-point depression, but our brine article gives 21.1 K (delta temp). Can the boiling point be elevated over this at such low pressures? -- 203.82.93.106 (talk) 20:23, 5 August 2011 (UTC)


 * I recall reading that Mars was at 20 degC when one of the probes landed on it, but I don't recall which probe it was and if that value turned out to be a measurement error or anomaly. Googlemeister (talk) 20:26, 5 August 2011 (UTC)


 * Per Climate of Mars the orbitally observed range is -143 to +27 C with a mean temperature of -55 C. The upper part of that range would allow liquid water even without solutes, but it would still turn to vapor under the very low pressures present at the surface.  Dragons flight (talk) 00:09, 6 August 2011 (UTC)


 * Some thoughts:


 * 1) Mars may have had a thicker atmosphere in the past. The magnetic field of a planet seem important here, as it deflects the solar wind, which would otherwise blow the atmosphere away.  Early Mars likely had a strong magnetic field, like Earth, due to a molten iron core.


 * 2) Modern Mars is rather desert-like, and deserts have extremes of temperatures. So, while the average temperature may be much lower on Mars, those portions in direct sunlight may warm up considerably, with little atmosphere and no oceans to support cooling and redistribution of that heat by convection. StuRat (talk) 21:38, 5 August 2011 (UTC)


 * From it appears that the observed flows occur just a little but north of the "frost line" in the "southern extreme transitional" zone of Mars - not in the tropics.  From File:MarsTopoMap-PIA02031_modest.jpg it appears that most of this region is actually higher than the average terrain on Mars, at +0 to +4 relative to something.  (For the Mariner probes the zero level used was the triple point of water, but I don't know how that relates to the scale on this figure).  So... although supposedly some locations on Mars might once in a blue moon rise up to as much as a balmy 80 degrees Fahrenheit, these slopes are cold - -70C to -100C.  But this is also a region of climate extremes, and I'm not quite sure what the climate is as the water is flowing.  The atmosphere should never be dense enough to contain the water.  Water on Mars gives an explanation that maybe the water starts flowing and freezes along the path, containing liquid water beneath it at higher pressure... not sure I believe that, but then again, at such tiny pressures as this, the force needed to keep the pressure qualitatively higher isn't really that much.  Hmmm... look forward to the explanation from the professionals. Wnt (talk) 19:19, 8 August 2011 (UTC)

Claims of Scientific Evidence Against Evolution
I have heard some people claim that there is scientific evidence against evolution. Is that true? If so, then what they? Are they really scientific evidences against it? — Preceding unsigned comment added by 110.174.63.234 (talk) 08:22, 5 August 2011 (UTC)
 * No they are not real scientific evidence against it. Real evidence agaisnt it would be for example fossils of rabbits in the precambrian. Nothing like has ever been observed. It is just people making it up, because they don't want to accept the massive biological evidence AND DNA evidence, AND fossil evidence that are all pointing to the same obvious conclusion: Evolution is a fact.--Lgriot (talk) 11:30, 5 August 2011 (UTC)
 * FYI, we have articles directly relating to Lgriot's claims: Precambrian rabbit & Evolution as theory and fact. &mdash; Scientizzle 15:29, 5 August 2011 (UTC)
 * The Talk.origins website has a taxonomically organised list of claims by creationists. Notice "claims", not "scientific evidence". The list is here. --Stephan Schulz (talk) 11:48, 5 August 2011 (UTC)


 * Fossil rabbits in the Precambrian layer wouldn't disprove evolution. Even I you could prove they were definitely from that time period, and weren't just some later insertion, it would only disprove our current models of common descent and maybe our current taxonomical theories. To disprove biological evolution itself would require something much more basic, like disproving that traits are physically inherited, or proving that each species can only vary within certain narrow parameters and that they therefore cannot drift more than a certain genetic distance from a somehow hardcoded 'typical' version of the species, or that no mutations ever produce viable offspring. Of course, we have such a wealth of data showing the opposite that you would also have to show how all this data could be wrong, while proving this unlikely scenario. It would have to be a proof on such a basic level, because biological evolution is a mathematical inevitability once you have inherited traits, variation in traits, and variable reproductive success. Even if the inherited traits had no impact on reproductie success, you would have genetic drift which is sufficient to establish new species if populations are isolated. This is, of course, why even many of those pushing for a creationist interpretation start introducing things like 'Intelligent Design' and 'microevolution': because any halfway intelligent person who looks at the evidence can see that evolution simply has to happen, unless our most basic assumptions about inheritability, or even cause and effect, are fundamentally broken. 212.183.128.47 (talk) 12:03, 5 August 2011 (UTC)
 *  it would only disprove [...] maybe our current taxonomical theories. Maybe??? Come on, mamals during the precambrian era!? it would maybe disprove our current taxonomy? It would be earth-shatering. We'd have to review everything end-to-end. I'd personnaly start wondering if something is playing a little game with us. And I'd be very interested in those theories that try to reconcile these rabbits with the taxonomy we now have. That would be a very interesting debate. --Lgriot (talk) 13:29, 5 August 2011 (UTC)
 * I can't help it: I read too much scifi. Time machine? Aliens? Separate descent of animals up to rabbits on Atlantis, spreading to the rest of the world when it sank? Rabbit-shaped plant roots? Rabbits turn out not to be mammals? Given that any theory has to explain why all the other evidence suggests our current theories as well as explaining the rabbit, I wouldn't like to say with certainty that it would actually suggest our underlying theories of how taxonomy works would necessarily be wrong, since it would be so unlikely anyway that an explanation that looks unlikely now might look more likely in the event. But even if we had to rework all of that from the bottom, it still wouldn't disprove evolution. 86.161.210.242 (talk) 15:23, 5 August 2011 (UTC)
 * Perhaps rabbits evolved intelligence and made an attempt at paleontology, with some casualties. ;) But seriously, there is a point there that if we can think of excuses for such a gaping hole in the theory, there's some doubt as to the falsifiability of the theory.  I don't think this is a problem limited to evolution though - any theory which is extremely fundamental to a science becomes difficult to falsify because there are so many lines of proof favoring it and so many ways to explain away one experimental observation (the Voyager data questioning whether gravity is really inverse square, for example).  There may indeed be some risk that a society could be "blinded with science" this way, but I doubt evolution (or gravity) is the example. Wnt (talk) 16:26, 5 August 2011 (UTC)


 * And, while we are on the subject, "What, if anything, is a rabbit?" AndyTheGrump (talk) 16:36, 5 August 2011 (UTC)


 * Maybe finding the Precambrian fossils of this rabbit would convince me, or at least convince me to run away... very, very fast. --Modocc (talk) 21:20, 5 August 2011 (UTC)


 * You mean Pioneer, not Voyager. The Voyagers weren't spin-stabilized, instead achieving attitude control through the frequent firing of thrusters.  The resulting unpredictable little accelerations are much too big for it to be possible to determine if the Voyagers have also experienced the Pioneer anomaly.  Red Act (talk) 17:35, 5 August 2011 (UTC)


 * Good catch! No wonder I didn't find the link. ;) Wnt (talk) 18:11, 5 August 2011 (UTC)


 * The honest answer is, of course there's scientific evidence against evolution. There's scientific evidence both for and against practically any proposition you care to name.  The problem is to weigh the evidence, and figure out, on balance, which side does it support more than the other. --Trovatore (talk) 22:35, 5 August 2011 (UTC)
 * Come on then. Give us the answer to the OP's question. What IS that evidence? I can't think of any. HiLo48 (talk) 22:47, 5 August 2011 (UTC)
 * I'll answer, but before I do let me clarify that I'm a biologist myself and pretty much totally convinced of the validity of evolution. The strongest evidence against it, in my view, would be cases where biological systems seem to show very sophisticated engineering, in ways whose natural origins we don't yet understand.  One very basic example is the genetic code, using triplets of DNA to code for amino acids; a less basic one that particularly strikes me is the modular structure of the cerebellum. Looie496 (talk) 23:28, 5 August 2011 (UTC)
 * I wasn't even necessarily going that deep. My point is more that evidence comes in chunks of all sizes; sometimes you put together a lot of little pieces of evidence, none of them very strong in themselves, to reach a scientific conclusion.  And there are certainly various small pieces of evidence against evolution.  For example, whenever we think that species B evolved from species A, but there must have been an intermediate type C, then if evolution is true, it is more likely to find C in the fossil record than if evolution is not true.  If, then, we have not found C in the fossil record, then in the sense of Bayesian inference, that is a small, scientific, data point against evolution.  It is not convincing in itself, but it is the sort of thing that could be added to a scientific case against evolution, and is therefore evidence.  --Trovatore (talk) 23:58, 5 August 2011 (UTC)

Creationists seeking scientific evidence to refute evolution is as absurd as evolutionists seeking scriptural support to deny creationism.Wolfgangus (talk) 09:20, 6 August 2011 (UTC)

Creation Evidence Museum! Axl ¤  [Talk]  21:42, 7 August 2011 (UTC)


 * Everything you wanted to know about inheritance of acquired characteristics and more: http://www.guardian.co.uk/science/2010/mar/19/evolution-darwin-natural-selection-genes-wrong . ~ AH1 (discuss!) 14:04, 8 August 2011 (UTC)

Fiat leporēs: The Spirit of God was hovering over the Precambrian waters, and he had a nasty flu that day from all the volcanism and shiz. And God said, 'Wed der be twewobits,' and lo there was wabbits. --  Obsidi ♠ n   Soul   06:12, 9 August 2011 (UTC)

Radio frequencies
I recently noticed my local FM station at 107.9 can also be heard at 86.5. Why is this? I know that the Intermediate frequency is 10.7 MHz, and 107.9 - 10.7 -10.7 is 86.5, though I have no idea how this plays into effect. Avic ennasis  @ 13:31, 5 Av 5771 / 5 August 2011 (UTC)


 * If you look at the station's website, you might find that it has a main transmitter and a relay situated somewhere else, in order to get better coverage. Hence, they'll be on separate frequencies.--Aspro (talk) 13:49, 5 August 2011 (UTC)


 * (ec)Broadcasters want everyone in a large area (say all of Belgium or all of Arkansas) to hear a station. But a single tower broadcasting will not reach the whole territory (for reasons of power use and topography). So they (or usually mast operating companies like Arquiva) built multiple towers (usually on top of hills) to "tile" the whole territory. In order to service people in remote valleys and people with rubbish antennas, these transmitters are a bit overpowered (than they'd need to be if everyone had a big antenna on their roof).  So if you live roughly between two towers, you can see both. In, above, we talk about the same scenario for TV reception.  But whereas TV antennas are (kinda) directional, you'd usually receive FM with an omnidirectional antenna, so you can receive signals from both towers on the same radio receiver, without having to do anything to the antenna.  To prevent the two towers from interfering with one another, they transmit on different frequencies. For you, between the two, you're getting a reasonably strong signal from both. You've not said what country you live in (and where) which would help us know precisely what's up, but the scheme is much the same the world over. You can search the website of whatever authority controls broadcast in your country (e.g. in the US it's the FCC) and find the locations of all the regional radio and tv broadcast towers (and their boosters), which usually also lists the channel assignment (the frequencies) each station is broadcast on from that tower.  Armed with that you can figure out the physical location from which you receive every signal. TL;DR - you're getting signal from different towers. -- Finlay McWalter ☻ Talk 13:50, 5 August 2011 (UTC)
 * I understand the use of multiple towers/frequencies to reach a larger audience. However, unless I'm mistaken, most FM radios in the US don't go below 87.5, which is why I'm surprised to hear content on 86.5. Also, if it matters, the callsign of the station heard on 86.5 is "Y108", the same as 107.9. If they were intentionally broadcasting on 86.5, wouldn't they have to identify that in some way? Avic ennasis  @ 14:04, 5 Av 5771 / 5 August 2011 (UTC)

The original signal at the intermediate frequency (IF) has to be mixed with another frequency to be converted to the carrier frequency. Mixing is kind of like adding and subtracting frequencies, so to get 107.9 MHz from 10.7 MHz, you need to mix it with 97.2 MHz (97.2 + 10.7 = 107.9). However, on the output of the mixer there will also be an identical signal at 97.2 minus 10.7, or 86.5 MHz. There is meant to be some filtering to remove the 86.5 MHz signal, but in this case some energy managed to get through to you, since none of the components are ideal. &mdash;Akrabbimtalk 13:55, 5 August 2011 (UTC)
 * I think your math is a little off. :-) If it helps, the local station is WDSY-FM. Avic ennasis  @ 14:04, 5 Av 5771 / 5 August 2011 (UTC)
 * Thanks, typos corrected (87.5 --> 86.5). &mdash;Akrabbimtalk 14:11, 5 August 2011 (UTC)


 * In that case, it might be a pirate re-transmission. Is this the first time you have noticed it; in other words, could it have just popped up during the summer vacation like so many pirate stations. Just looked up the US frequency allocations and this is for television, non government broadcasts;  that finishes at 88mhz with FM radio above that. So, off-hand I cant think of any legitimate reason that it should be there. Also, if you can receive it way-down-there on 'your' radio, it suggest to me there might be a slight chance that you also  have your rig wired up to a rotatable  array of some sort, in which case  you could have a go at  DXing  its location and reporting it.--Aspro (talk) 15:02, 5 August 2011 (UTC)

Akrabbim is correct and the effect is described at Superheterodyne receiver. The guesses above about multiple transmitters, pirates and a direction-finding rig are all wrong. Cuddlyable3 (talk) 16:09, 5 August 2011 (UTC)

The "Laotian bird" Nock-ten (2011)
I have posted a question here at the language desk asking for a reliable source explaining the nature of the "Laotian bird" for which this storm is named. Comments there by those who might have a clue would be appreciated. μηδείς (talk) 15:57, 5 August 2011 (UTC)
 * I don't know. But a source that looks like it actually took a moment to do some translation says it's Laotian for "bird" (rather than a kind of bird).  True, most of the world's media says that it's a "Laotian bird", but I have a sinking feeling they're all copying each other and a 2004 Wikipedia article.   This becomes increasingly a worry - as Wikipedia becomes the only easy source for looking up certain things, we may end up breathing our own exhaust. Wnt (talk) 17:28, 5 August 2011 (UTC)
 * Maybe we're looking in the wrong place. Tropical Storm Nock-ten (2011) says it was the Japan Meteorological Agency (JMA) which gave the storm that name. Maybe it would be more reasonable to assume that it's a Japanese word, maybe for a Laotian bird. HiLo48 (talk) 22:39, 5 August 2011 (UTC)


 * Japanese words don't end in -ck, either by pronunciation or spelling. The -ck spelling convention alone, limited pretty much to English and German, makes the Lao-ness of the word as written suspect.  We seem to be dealing with a word reported at several removes from its origin, like the various English transliterations of the Russian name Fyodor or Feodor (spelt Фёдор) which comes from the Greek  Θεόδωρος (Theodōros), "Theodore".  The best hint I have found so far is that the Thai language wikipedia article for the storm links to the Thai article on kingfishers.  μηδείς (talk) 03:37, 6 August 2011 (UTC)


 * Is this helpful? It suggests that the Thai for "kingfisher" has both the syllables "nok" and "ten" in it. Bielle (talk) 03:45, 6 August 2011 (UTC)


 * See Lists of tropical cyclone names. Given the way the naming works, there's little doubt it came from Laos. Regional Specialized Meteorological Centre in Japan which is operated by the Japan Meteorological Agency is in charge of the naming but they use the process outlined there/Tropical cyclone naming/. Lao script gives wiktionary:ນົກ or nōk as meaning bird. That article and Romanization of Lao isn't particularly clear on what, if any specific, romanisation is normally used by the Laotian government but I presume the specific romanisation was submitted by whoever in Laos was in charge of submitting the name. Given the relationship between Thai and the Lao language and the above, it seems likely the meaning is something akin to kingfisher. Nil Einne (talk) 09:58, 6 August 2011 (UTC)
 * Yes, nok is certainly the word for bird in both Lao and Thai. A kingfisher is nok kraten in Thai (นก กระเต็น) and in Lao they've probably just shortened it (or maybe it was the other way around).  Sean.hoyland  - talk 10:30, 6 August 2011 (UTC)
 * Hmmm, that last link gives a script that delivers in Wiktionary, so maybe "นก-เต็น" is the actual word in one or the other language? This seems to be bringing up search hits about the hurricane (e.g. ), though often without the hyphen.  But searching that in dictionary pulls up นักเต้น (náktên), defined as "dancer".  This discussion is a comic (but not so comic) demonstration that - despite some very useful accomplishments - Wikimedia projects still have a serious need for better communication between languages and cultures ... Wnt (talk) 14:17, 6 August 2011 (UTC)
 * Yes, the Thai press are using นก เต็น (nok ten) as the Thai script transliteration of the Lao ນົກ​ ເຕັນ  Sean.hoyland  - talk 17:55, 6 August 2011 (UTC)
 * [From the Language desk] :The Lao spelling appears to be ນົກເຕັນ. This appears to be a name for the kingfisher.. This recent blog post seems to link ນົກເຕັນ with the Common Kingfisher and with the storm (I can't read Lao). Also, if you go to this dictionary, and search for kingfisher in the box marked "Text", you get the entry for ນົກເຕັນ. Unfortunately I don't know how to link to the entry directly.--Cam (talk) 23:55, 6 August 2011 (UTC)
 * It was Laos who submitted the name to the WMO Typhoon Committee back when the names were devised in the late 1990s assigning it the meaning "bird" HKO, JMA. The Typhoon Committee then selected the JMA to assign the names as it was already their Regional Specialized Meteorological Centre for the region.Jason Rees (talk) 11:07, 7 August 2011 (UTC)

Thanks, all. I have modified Nock-ten (2011) based on the responses and suggest readers check that article- it could use help from the knowledgeable and even lay native angloparlantes. μηδείς (talk) 03:55, 7 August 2011 (UTC)

When in the history of Astronomy could a planet on the far side of the sun be ruled out?
Hello everyone, bit of a conundrum for you. A common speculation in the old sci-fi genre over the years has been a planet orbiting the sun in the same orbital plane as the jolly old Earth but exactly opposite us, so it was always concealed behind the Sun. I was wondering is any of you fine chaps could tell me when such an idea could be definitively proven to be merely a fancy. Not being too up on the old star-gazing routine I'm a bit stumped! I would imagine it could perhaps either been when our understanding of the solar system and our ability to see the effects of a heavenly body's gravitational field on other heavenly bodies was mastered. Alternatively perhaps when those very clever chaps started launching those space probes and the telemetry showed no such place.

Can any of you fine fellows help an old duffer out here? It's a bit hard on the old noggin don't you know. Chin chin! Quintessential British Gentleman (talk) 18:42, 5 August 2011 (UTC)
 * Yeah, you basically answered it yourself. We'd see such a planet's gravitational effect on other astronomical bodies (Neptune, for example, was expected to exist before we actually observed it...sort of). You might be interested in 2010 TK7, an asteroid that shares Earth's orbit. --Goodbye Galaxy (talk) 19:24, 5 August 2011 (UTC)
 * Right... but that wasn't your question! Whoops. If I had to guess, I'd say around late 1700s to mid 1800s, but I'm not entirely sure. --Goodbye Galaxy (talk) 19:27, 5 August 2011 (UTC)
 * If it was a small planet, like Mercury or smaller, it could hide longer then another earth sized planet could, but at some point, the IAU would take away the planet status. Googlemeister (talk) 20:23, 5 August 2011 (UTC)


 * A so-called counter-Earth would have been known since antiquity, since it would periodically be visible from Earth. First, Earth's orbit is elliptical and not circular, so a planet that was following the same path about the Sun would 'gain' on us when it was close to the Sun, and fall behind when Earth was close to the Sun.  (This problem could be avoided if the counter-Earth were in a symmetrical orbit.)  The second problem is that the Sun's position is perturbed by the other planets (especially Jupiter) and so wiggles back and forth; depending on where the counter-Earth was in its orbit, it would periodically peek out from behind the displaced Sun.
 * Leaving aside those issues, a planet of Earth's mass sharing our orbit wouldn't be dynamically stable. (Or, alternatively, our orbit wouldn't be stable.) Small perturbations (caused, for example, by the other planets) would lead to exponentially growing imbalances in the forces on the counter-Earth, relatively rapidly dragging it out from behind the Sun.  The mathematics governing Lagrange points (a counter-Earth would be at L3) showed up in the eighteenth century; presumably a capable astrophysicist of that era would have been able to determine that no stable counter-Earth orbit could exist. TenOfAllTrades(talk) 20:51, 5 August 2011 (UTC)
 * The point that any sufficiently large "counter-Earth" would be periodically visible, would have followed from the studies of Kepler in the early 17th century, right? 188.117.30.209 (talk) 08:54, 6 August 2011 (UTC)


 * If it was small enough and dark enough, we might not know about it even now. Of course, as noted previously, something that small can't really be called a planet.  However, the definition of a planet includes it clearing it's orbital path of debris, which is difficult to determine if the path was cleared, but presumably mainly by the Earth. StuRat (talk) 21:28, 5 August 2011 (UTC)

Is Wikipedia auditioning for the part of Colonel Blimp? Cuddlyable3 (talk) 21:45, 5 August 2011 (UTC)


 * Hmmm, it's true that the center of mass of the Sun and Jupiter is outside the Sun. But wouldn't the Earth and Counter-Earth, being bodies orbiting the sun, follow it on its orbit around its center of mass with Jupiter, thus remaining in line with one another and the Sun? Wnt (talk) 22:54, 5 August 2011 (UTC)
 * Jupiter's period of rotation is much longer than that of Earth, so they wouldn't be synchronized. Rckrone (talk) 03:09, 6 August 2011 (UTC)
 * I don't think that matters. If the Sun is (a little bit) revolving around Jupiter, then the Earth should be revolving around Jupiter too, as a "moon" of the Sun when looked at this way.  Whenever the Sun is on one side of Jupiter (or the barycenter) the Earth is also. Wnt (talk) 14:22, 6 August 2011 (UTC)
 * Yeah, you're right. Rckrone (talk) 21:37, 6 August 2011 (UTC)

Do you have a source or link for the Jupiter-Sun barycenter claim, Wnt? μηδείς (talk) 03:40, 6 August 2011 (UTC)


 * See barycenter for one source (NASA).--Shantavira|feed me 07:52, 6 August 2011 (UTC)


 * Wow. That's great.  I am truly impressed by what one learns from wikipedia, as opposed to those moribund rags like Scientific American and National Geographic.  Why had I never heard this before?  μηδείς (talk) 03:52, 7 August 2011 (UTC)

Thanks everyone for chipping in. I didn't know about that Counter-Earth article, so essentially even before space probes could have seen the area a counter-earth would've either been visually spotted due to the elliptical nature of earth's orbit or it's existence disproven either mathematically or by lack of observable gravitional effects on other planets, and it's likely that the theory was discredited anytime from the 17th century onwards. Thanks chaps, much appreciated. Keep up the good work. Quintessential British Gentleman (talk) 12:21, 6 August 2011 (UTC)


 * If the planet only "peeked out" a little from behind the Sun occasionally (which seems improbable - it would more likely wander widely), it would only be potentially visible without the aid of modern-ish instruments during total solar eclipses. However its gravitational perturbations on other planets (like those of Neptune on Uranus which led to Neptune's discovery) would have been obvious to astronomers from Newton onwards, as has been said above.
 * The concept was used for the locale of the Gor series of SF novels by "John Norman", which was subtitled The Chronicles of Counter-Earth. Norman avoided the problem by having the planet be the home of an advanced alien race, the giant-ant-like "Priest-kings", who used their advanced technology to tweak its motion, keeping Gor always exactly opposite Earth and presumably also adjusting the other planets' perturbations. {The poster formerly known as 87.81.230.195} 90.197.66.72 (talk) 17:44, 6 August 2011 (UTC)

move the world
One of the ancient philosophers, maybe Archimedes, stated that with a large enough lever and a place to stand he could move the world. I have my doubts on that. Given known materials, would it be possible to construct a lever capable of moving the earth a distance of 1 cm if we could assume that a 180 lb Archimedes had a place to stand, and a fixed point where he could use his lever, (we should probably assume that he needs to be capable of moving his lever as well)? My guess would be that even if his lever was a Titanium alloy, the lever would need to be so long that poor Archimedes would just have his lever flex on him rather then lifting the earth, but I am only assuming here. Googlemeister (talk) 20:46, 5 August 2011 (UTC)


 * Agreed, no real-world material would work. Also note that such a lever would be quite massive, so it's gravitational effect on the Earth might well outweigh any use as a lever. StuRat (talk) 21:30, 5 August 2011 (UTC)
 * (ec)We can't assume what you ask so it's not our problem. Cuddlyable3 (talk) 21:34, 5 August 2011 (UTC)


 * It should be noted that you don't need a lever to move the world. Any amount of force will do, for example just jumping up and down.  Granted it won't move the Earth by 1 cm.  But if you're allowed to start not on the Earth ("a place to stand") then you could theoretically shoot yourself at the Earth with enough energy to change it's orbit by 1 cm, or any amount that you like. Rckrone (talk) 22:39, 5 August 2011 (UTC)


 * According to my rough calculations, if you can find a material workable enough to shape and rigid enough so as not to bend too much, you can nudge the earth over a bit. The trick is to get enough of the material to create a lever with a length something in the range of 100 to 1000 times the diameter of the observable universe. (Less if you weigh more than 200 kilos and are quite strong.)


 * As noted these are "rough calculations" so please get input from another person at this desk before starting fabrication. CBHA (talk) 23:46, 5 August 2011 (UTC)


 * A problem here is that like any object, the Earth's doesn't have a precisely defined momentum and position. The uncertainty in the momentum is actually quite large, it's of order sqrt(M k T) with T the temperature at its surface. This means that it becomes a problem to say that a small amount of momentum, say, of order 10 kg m/s added to the Earth actually changed its orbit. The probability that nothing changed at all will be significant. Count Iblis (talk) 00:35, 6 August 2011 (UTC)
 * He was correct, but would need a lever approximately 5973600000000000000 kms long, according to my (probably wrong) strokes on the calculator, for a push on the lever of about 10kg. It would need to be a thicker lever the closer it gets to earth so it doesn't collapse under the gravitational effects of bodies in the solar system. The hinge required needs to whitstand the force from said gravity, as well as force from the leverage, the faster he wants to move the earth, the stronger the hinge, foundation and lever need to be. Use the ratio of the 1cm : length of lever, which will be the same ratio as the mass of the earth : force applied to lever's end. He weighs 90kg, but he'd need to be in a 1G environment in his 'place to stand' which would clearly need to move if he is to stand. He needs to move through 5973600000000000000 kms for the earth to move 1cm. Anyone want to check/correct the figure ? Penyulap   talk 13:21, 6 August 2011 (UTC)

Archimedes did not specify a distance. His boast was most cromulent. μηδείς (talk) 03:47, 7 August 2011 (UTC)


 * Cromulent, although unpractical. Plasmic Physics (talk) 00:05, 8 August 2011 (UTC)


 * So a meter shove of the lever moves the Earth somewhere around 10^-24 meters? That's like 10^-14 Angstroms, and something like a billionth of the size of a proton?  Does that count as moving the Earth, if you can't make any observation that would detect the difference, and it is very strictly a statistical effect? Wnt (talk) 19:25, 8 August 2011 (UTC)

So, your question is, "Does actually moving the Earth actually count as moving the Earth?" You can, of course, be killed by things you are not aware of. Ergo.... μηδείς (talk) 00:49, 9 August 2011 (UTC)


 * Well, if you "move" the Earth in this manner, and you take a poll of the positions of a billion atomic nuclei... half of them have moved one way, half the other. Maybe on average the number moving one way is 1 greater than the number moving the other.  Does that count as "moving" it? Wnt (talk) 05:36, 9 August 2011 (UTC)


 * Let me paraphrase you: "Well, if you "move" the Earth in this manner, ... does that count as "moving" it?"


 * Unless you want to argue struthiously that what you personally aren't in a position to observe doesn't exist, the logical form of your question is to question the validity of the proposition A > A. μηδείς (talk) 18:57, 9 August 2011 (UTC)