Wikipedia:Reference desk/Archives/Science/2016 March 1

= March 1 =

Mens Vescicles
How full cn they get before expelling? ie how much liquid can they hold:?--31.109.183.147 (talk) 01:14, 1 March 2016 (UTC)
 * Depends what size mallet you hit them with. ←Baseball Bugs What's up, Doc? carrots→ 02:00, 1 March 2016 (UTC)
 * Well BB, I never ever thought you would make me laugh, but you have (out loud)! Very, very funny. But judging by thier location, I think only a very small and specially shaped mallet would suffice.--31.109.183.147 (talk) 02:30, 1 March 2016 (UTC)
 * Ignore the pointless 'jokes' above.... I haven't found a reference for maximal volume, but our semen article suggests an average ejaculation is 3.4 ml, and our seminal vesicle article tells us that they are responsible for 70-85% of the volume of an ejaculation. That at least gives you a rough idea. Fgf10 (talk) 08:33, 1 March 2016 (UTC)
 * The OP liked it. ←Baseball Bugs What's up, Doc? carrots→ 00:35, 2 March 2016 (UTC)
 * Yes indeed Bugs. A refreshing change! Keep em 'coming'--31.109.183.147 (talk) 01:02, 2 March 2016 (UTC)

Clock reverses movement direction
My brand-new wall clock demonstrated 'bizarre behaviour' as seen in the short video. This cyclic movement continued for an hour and ended in a complete stop of the clock. I took the battery out and found it was full. After putting it back the clock continues to function properly. Could anybody explain this? Etan J. Tal(talk) 05:45, 1 March 2016 (UTC)


 * Does it happen to be a clock that synchronizes itself with the radio signal from NIST? Bubba73 You talkin' to me? 06:41, 1 March 2016 (UTC)
 * No synchronisation. This is a simple clock. Etan J. Tal(talk) 07:29, 1 March 2016 (UTC)
 * My guess is that the motor which controls the second hand is broken or misaligned in some way: a gear is slipping so its teeth engage incorrectly (perhaps with another gear) which causes it to turn the wrong way. You'd have to take the clock mechanism apart and watch it directly (there are probably several gears and a motor running the whole thing) to diagnose the source of the problem.  -- Jayron 32 12:57, 1 March 2016 (UTC)
 * I think this may be a quartz clock that uses a latching escapement with a pawl and ratchet. The pawl rides up the tooth, drops into and engages with the tooth, and pulls the gearwheel one increment of rotation. Or, the clock may contain a drive based on the toothless (rubber) ratchet described in that ratchet article. I wonder whether the OP brought the clock in from an unusually cold outside environment and there was significant backlash in the mechanism until it warmed up to room temperature. Incidentally, the description of the action of the pawl that I described above differs from that in the ratchet article. In my experience as firstly, a Strowger switch telephone systems technician and later a servicer of time-clocks in factories, the pawl was the arm that pulled or pushed the gearwheel one increment of rotation electromagnetically by the energizing of a coil with electric current. In the article, it is described as a passive device that merely allows one-way rotation. Akld guy (talk) 15:41, 1 March 2016 (UTC)
 * It's probably just a case of the depleted battery not being able to overcome the weight of the second hand. It reaches the 9 o'clock position, the motor gives up, the hand falls back (either under its own weight, or because the motor has reversed) until it reaches the 6 o'clock position where the motor is powerful enough to lift it again.  See brushless DC motor for technical details. Tevildo (talk) 19:23, 1 March 2016 (UTC)
 * But he said the battery was full when he removed it after one hour. Moreover it was a brand new clock, which he may have just brought in from the cold outside. Akld guy (talk) 20:02, 1 March 2016 (UTC)
 * Right now the clock functions OK with the same battery. No temperature changes could affect the clock. I suppose a Post-Mortem will solve the puzzle... I thank all participants for collaborating. The video is now included in https://en.wikipedia.org/wiki/Surprise_(emotion), https://en.wikipedia.org/wiki/Chronemics, https://en.wikipedia.org/wiki/Clock. Etan J. Tal(talk) 20:16, 1 March 2016 (UTC)
 * I've reverted a couple of those - I don't think it was relevant to any of those pages. SteveBaker (talk) 21:05, 1 March 2016 (UTC)
 * Let's hope so! One point - just because the open-circuit voltage of the battery is the same as the nominal voltage, that doesn't mean it's fully-charged.  You really need to measure the voltage with a load applied to confirm it's OK.  Try measuring the voltage when it's actually in the clock - if it's OK there, then there may indeed be a problem with the clock motor. Tevildo (talk) 20:59, 1 March 2016 (UTC)
 * The type of battery clock shown typically contains an oscillator circuit that drives a small single-phase Synchronous motor. Since the motor may start rotating in either direction a means is added to stall the motor if it chooses to run backwards; this may be done by a tiny ratchet wheel that is clogged, slipping or broken in the OP's clock. AllBestFaith (talk) 21:03, 1 March 2016 (UTC)
 * I can understand the concept of a ratchet stopping backwards sweep of the hands at startup (presumably battery insertion), but that is no explanation for what the OP filmed - the clock running normally and then for no apparent reason reversing. Akld guy (talk) 21:16, 1 March 2016 (UTC)
 * What's the point in deleting the only video clip from https://en.wikipedia.org/wiki/Clock ? I wonder... Etan J. Tal(talk) 21:35, 1 March 2016 (UTC)
 * @Etan J. Tal, see . Discuss at Clock talk page if in doubt. AllBestFaith (talk) 03:02, 2 March 2016 (UTC)
 * This should be discussed on the relevant talk page(s) rather than here. But a guiding principle here is not to say to oneself "Ooh! I have this interesting video/picture/quotation - what are all the places I could insert it into Wikipedia articles?".  No!  The correct mindset for a good Wikipedia contributor is "Hmmm - this article that I'm writing could really use a video/picture/quotation to further expand on this important point - I wonder if I can find something appropriate?".  Taking that view, none of the three articles that you added the video to actually needed a video of a broken clock in order to explain some important point about their subject.  That's why it's been reverted.  It's a common mistake - and no personal criticism of you or your efforts to help out is intended. SteveBaker (talk) 15:34, 2 March 2016 (UTC)
 * I do understand your POV, but I humbly disagree. My personal “Hmmm…” works according to a different mindset, which stems from the following credo: “Hmmm – this photo I have is unique since it has the potential to expand the reader’s knowledge”. It is essentially the opposite way of yours. It is not better, nor truer, but not less valid. There is no single “correct mindset for a good Wikipedia contributor” as you suggest, and it is probably not “a common mistake” as you conclude. Your knowledge starts from the text while mine (sometimes) starts from the visuals. Trying to decipher a visual (photo or video) frequently leads me to explore new topics, which would have stayed completely unknown to me. If I happen to sound record a rare bird, wouldn’t it be a good contribution to WP if I include it in the bird’s article? (This example demonstrates how knowledge might start from the audio channel). The same with the clock: The nature of a clock (save sundials) is its mechanism movement. Hence, it is completely acceptable to include a video clip, which shows this characteristic in the WP article. It is just a (blessed) coincidence that the mechanism was defective, that one can see both normal and abnormal function of this device. The same argument is valid to Surprise. Isn’t that a good example to demonstrate surprise using a non-verbal channel? I do not know if my POV is convincing, but unreverting the video clip will show. Etan J. Tal(talk) 18:43, 2 March 2016 (UTC)
 * I have a quartz clock which is battery operated.  When the battery runs out it stops marking time, but there is a sign of life in that the sweep second hand jerks without, however, going anywhere.   It does this at the usual rate of once per second, i.e. normally it circles the dial in 60 steps.   The second hand in the video, however, moves smoothly when it's working properly, so are there two types of motor?   Am I right in thinking that in the version I have the second hand engages a gear which moves the minute hand which engages a gear which moves the hour hand?
 * On one occasion I noticed different behaviour when the battery was low.  The second hand behaved normally until it reached "11", when it jerked without going anywhere for two seconds, and then moved forward three divisions on the third second.   Thus it ended up where it was supposed to be but did it in a funny way.   Can anyone explain how it could behave like that? 86.143.178.84 (talk) 16:34, 5 March 2016 (UTC)

Paper consumption in weighbridge in thermal power plant
What data is recorded in 1 weighbridge for railway rake laden with bituminous coal in a coal fired thermal power plant with two 300MW units and if maximum 3 rail rakes arrive a day assume units are operating continously 24x7x365.Similarly what data is recorded by another 1 weighbridge for ash dumper.If the two weighbridges are taking printouts of the data for coal rakes and ash dumper in 10x12 60GSM dot matrix printer paper what will be rate of consumption of paper.How many reams will be consumed anually and monthly in full load and if its is assumed that sometimes the units are operating at lower load and very infrequently shutdown for O and M activity and sometimes coal rakes are not arriving in all scenarios what will be the maximum/ minimum and average possible consumption of consumption of 10x12 60GSM paper reams.In what time will 50 reams of this paper  and 100 reams of this paper will last in maximum /minimum and average generation per unit say 280MW.This is not a homework question. An individual was put into a situation where this info was needed the central point was whether 100 reams of this purported paper really needed in subtropical climate because it is needed to know if genuinely this rate or quantity of paper consumption true for two dot matrix printers in real life question is about the feasibility of this requirement in this scenario in absolute real life and no virtual homework scenario150.242.150.177 (talk) 07:47, 1 March 2016 (UTC)

Roger (Dodger67) (talk) 09:41, 1 March 2016 (UTC)


 * I'm sure the OP is evidentally not a paper technologist (or I guess now weightbridge) so this supposedly means this can't be a homework question. Reference desk/Archives/Science/2016 February 9. BTW from what I can tell it's not possible to answer any part of this question even if we wanted to. It's missing key information. Either the OP didn't copy the question correctly of the white/blackboard, or they didn't copy it correctly off their exercise or question sheet the teacher handed out or relies on specific knowledge about the weightbridges, power plants, coal rakes and ash dumper they're studying. (But I'm not really sure why a question like this would come up if you're studying that.150.242.148.86 (talk) 12:32, 1 March 2016 (UTC)Nil Einne (talk) 12:21, 1 March 2016 (UTC) An individual was put into a situation where this info was needed the central point was whether 100 reams of this purported paper really needed in subtropical climate because it is needed to know if genuinely this rate or quantity of paper consumption true for two dot matrix printers in real life question is about the feasibility of this requirement in this scenario in absolute real life and no virtual homework scenario.I want a realistic estimate based on real life scenario where wide variations is taken to account that is not unitary method and no homework this is. What more info is needed.??? 150.242.150.138 (talk) 12:37, 1 March 2016 (UTC)


 * That will depend on the make and model of the printer, the font size being used, and exactly what data the system has been set up to record. I agree that the question as it stands is not answerable. — Preceding unsigned comment added by 109.150.174.93 (talk) 13:32, 1 March 2016 (UTC)
 * To reiterate the above comment, the key information which is missing is an understanding of what is recorded each time a "railway rake" is weighed on the weighbridge. It might be a single line of text. It might be a page of text. Without this, we cannot proceed. We can make some asumptions - let us ignore the ash business, for a second: suppose that we record date, time, weight, for instance, whenever a delivery is made. That should fit on a single line. 3 lines per day. Say 60 lines are printable per sheet of paper. So a single sheet of paper will last for 20 days. However: let us suppose that each "railway rake" requires two pages to be printed, one for the recipient and one for the train company. That would take 6 pages per day. I trust you now see that we have insufficient information to assist. (In other news: 24x7x365 is nonsense. 24x7 says "full time". 24x7x52 also says "full time". But there are not 365 7-day weeks in a year, and so that says "nonsense".) --Tagishsimon (talk) 17:17, 1 March 2016 (UTC)

Why do wooden ships sink?
Is it solely due to ballast and/or cargo? Or is there some other reason? -- I have seen a sailing yacht (~40ft.) on the seafloor that was almost entirely wooden. ~E:70.193.32.201 (talk) 16:58, 1 March 2016 (UTC)
 * See Shipwrecking (also called "foundering") for a decent Wikipedia article discussing the cause of ships sinking. -- Jayron 32 16:59, 1 March 2016 (UTC)
 * Interesting article, but doesn't directly address the question (i.e.: since wood floats, why do wood boats sink?). ~E: 2600:1004:B048:B35E:9FB:8216:A16D:67CA (talk)
 * For the record, many woods are denser than water (~1,000 kg/m3), and a few are even denser than seawater (~1029 kg/m3) . Lignum_vitae is a notable example, but they probably don't build wooden boats out of it. SemanticMantis (talk) 17:18, 1 March 2016 (UTC)
 * In that case this forum thread seems to be a pretty good overview. -- Jayron 32 17:21, 1 March 2016 (UTC)


 * It is just down to ballast. For stability, the centre of gravity should be below the centre of buoyancy. Otherwise there is a danger of the ship/boat turning turtle in rough seas. The amount of stone ballast required to achieve this stability is greater than the buoyancy of the wooden structure itself. So once the ingress of water over-comes the total  buoyancy due to displacement … the whole issue joins Davy Jones' Locker. --Aspro (talk) 19:24, 1 March 2016 (UTC)


 * Even wood that floats is mostly close to the density of water, so that even a small amount of denser material, like nails and cannons and cargo, will make it sink. Plus eventually the wood on a sunken ship will become waterlogged, and encrusted with barnacles and such, which may increase the overall density further. StuRat (talk) 19:48, 1 March 2016 (UTC)


 * The most obvious reason for a wooden ship to sink is that a hole allows water to enter the portion already below the water level, so that the air-filled hull no longer displaces enough water to make the ship bouyant. A wooden ship struck below the waterline by a cannonball, or by hitting a rock, or being rammed by another ship or which has had a hole drilled in the hull or a porthole left open when the ship is tilted over by the wind might sink from water entry. A floating thing without such an airfilled waterproof hull might be termed a "raft" which merely relies on the logs having less density that the water they float in. In the days of sailing ships, it was sometimes the case that a ship hauling logs would have its hull fill with water, but the deck would remain just above the surface for a very long time, with the crew living a miserable existence until some other ship saw them and rescued them. The surviving crew might have little food fresh water or shelter. Some such derelict ships floated around in the North Atlantic for years, one of hundreds such: . Edison (talk) 21:41, 1 March 2016 (UTC)


 * Wooden ShIps don't sink. μηδείς (talk) 02:12, 2 March 2016 (UTC)


 * for your replies. ~E: 2600:1004:B05E:A73:A4B5:DD7D:BB8:5BBF (talk) 06:39, 2 March 2016 (UTC)

Quality of a television output
Why does it always show good quality picture in television when satellite channels are showing a cinema or a serial...? – comparing with watching a movie in a cinema theatre, buying a DVD, watching it in the computer, and so on. -- Apostle (talk) 18:24, 1 March 2016 (UTC)
 * So many possible reasons images may not be great.


 * For movie theatres: projected light levels; physical quality of the screen; whether or not the movie is being projected from film or digitally
 * DVDs: Generally not in HD (as opposed to Blu-ray); quality of the player; ability of player to Video scaler
 * Computers: video cards and/or monitor quality; settings on the computer
 * Since theoretically TV broadcasts over satellite are set up correctly from the start with the minimum of setup, it could easily be the best of the bunch for the averagee viewer. Mingmingla (talk) 18:59, 1 March 2016 (UTC)


 * I don't agree that satellite TV is better quality than a movie theater. In the US, it will generally only be 720p or 1080i resolution, while movies in theaters have better resolution.  However, the much larger screen in the theater means that the "pixels" may appear larger, and if you sit close to the screen, it may look grainy.  Another advantage to the theater is that the room is quite dark, versus many homes that are not. StuRat (talk) 19:40, 1 March 2016 (UTC)


 * The OP didn't specify exactly what is meant by "watching it in the computer", but if the video is being streamed over a network from a remote site, as opposed to playing a local file, then the quality of the network connection comes into play. Many streaming sources automatically decrease the bitrate (and therefore quality) of a stream in response to degradation of network throughput.  Mnudelman (talk) 19:47, 1 March 2016 (UTC)


 * Terrestrial television, cable and satellite transmissions endeavour to provided a signal with sufficient band width (5 Meg or more) in order to provide good reception. If your not getting it, then is is more than likely down to the hardware at your end. --Aspro (talk) 19:52, 1 March 2016 (UTC)


 * I imagine it depends on the cable TV system, but my impression is they were basically just satellite TV with the dish in a remote place (and some options for internet connectivity). I suppose nowadays some might download the DVD via the Internet and have it ready for more reliable transmission, but to this day I think most cable systems will often go out when there are high winds that misalign the company's dish, or blank temporarily while some passing cop is playing with a radio transmitter. Wnt (talk) 21:16, 1 March 2016 (UTC)


 * Sorry for the delay, I ran out of internet 'kbs'.
 * I understand. Well I still think TV picture is better than any other; I guess I could be wrong... Thanks for the clarification peeps. Regards. -- Apostle (talk) 22:06, 3 March 2016 (UTC)

Food of the future News
Does anybody have any idea about the entitled news showed on the news channel called Aljeezera ? -- Apostle (talk) 18:24, 1 March 2016 (UTC)


 * Don't understand your question. Are you asking if Al-Jazeera is more reliable that Fox News (Ho, Ho, Ho.); (Or should that be faux news). Think this ought to be re-posted on inhumanities ref desk. Just a thought.--Aspro (talk) 19:34, 1 March 2016 (UTC)
 * I would definitely consider Fox to be more reliable for sports news. ←Baseball Bugs What's up, Doc? carrots→ 02:19, 5 March 2016 (UTC)


 * The OP never once mentioned Fox News, so I'm not sure why you felt the need to bring it up. The most recent story on Al Jazeera's website related to "food of the future" is this story from 6 February 2016.  Perhaps that is the story the OP is asking about?  If that is the story, the website of the company so profiled it here and there's another profile of their work here on Newsweek and Here is information from the same time frame covering other companies doing similar work, on the Smithsonian's website.  -- Jayron 32 19:42, 1 March 2016 (UTC)
 * Sorry for the delay, ran out of internet 'kbs'.
 * Thanks J. I appreciate it...
 * Btw, I think Aspro was joking. I'm also guessing that he forgot to put it in small...lol
 * Regards. -- Apostle (talk) 22:06, 3 March 2016 (UTC)

Btw, if anybody knows what software(s) the companies are using to break, understand and or combine the molecular structures of the products/items. Let me know... -- Apostle (talk) 22:06, 3 March 2016 (UTC)

Is everyone does Valsalva maneuver?
I've read in a forum, discussion about Valsalva maneuver. One says in the name of the physiologists that it's dangerous while the other says that it can not be, since everyday does it when he goes to the toilet and another example is about those who go to the gym and do "deadlift" that it can not be done without Valsalva maneuver. Is that true? and Who's right? I'm confused about. 93.126.95.68 (talk) 21:02, 1 March 2016 (UTC)
 * See Valsalva maneuver. According to our article, there is a slight risk of retinal detachment. Tevildo (talk) 21:08, 1 March 2016 (UTC)

Bandwidth of alien broadcasts.
Suppose the SETI folks actually detected a transmission from a star a couple of hundred lightyears from here.

What kind of bandwidth could that transmission have?

In stories like Contact (novel)/Contact (1997 American film) we seem able to get a truly gargantuan amount of information from alien worlds - over not much time.

Is there a way to put a reasonable limit on the amount of bandwidth the aliens would be able to pack into a signal that SETI could be expected to pick up? If they are transmitting in the Water hole - that's a 1,500 MHz signal, so I suppose nyquist sets a limit at 750 Mbits/second. That's pretty good by Internet standards - but are there other limitations that would peg it at a much smaller number?

What about the idea that they'd use the water hole frequency to tell us "Please tune to XXX GHz for the actual message." - what could they manage at other frequencies?

SteveBaker (talk) 21:14, 1 March 2016 (UTC)


 * The biggest issue is the speed of light delay means it would be twice the distance in light years before the aliens would get a reply from us, and be able to focus all the energy of the planet at us in a narrow band transmission. Until then, they are only likely to send out very simple "Here we are" messages that can be broadcast in all directions. StuRat (talk) 21:49, 1 March 2016 (UTC)


 * My question came from a thought about exactly that. But I'm not asking about delay - I'm asking about bandwidth.


 * If I was living in a relatively advanced technology (say, 50 years in advance of ours) with lifespans only reasonably extended from ours (200 years maybe), and faced with the same problem of that lightspeed delay over 50 to 100 light years, I'd want to avoid a to-and-fro conversation taking millennia because I'd never live to hear the answer.


 * The way I'd try to avoid that would be to send a description for a simple programming language and an artificially intelligent 'bot' program written in that language - along with (say) a complete copy of Wikipedia or something like that. Assuming the programming language could be simply described in terms of mathematics (which, I think would be relatively easy once you get past the "Ooh! Look! They're sending us the first 10 digits of pi in base 12!" stage) - it ought to be possible for people with 21st century Earth-like tech to be able to figure out how to run the AI bot and chat with it.  That would allow them to teach it their language (so they don't have to figure out how to ready my Wikipedia-thing) - to ask it all sorts of questions about my civilization, to build up trust and friendship - then to have my AI start to ask them questions about their civilization, and after a relatively short period of time (a few years, lets say), to have them send a similar AI+Wikipedia package back to me in return so I can find out a huge amount about their civilization.


 * Taking that approach would allow both civilizations to gain a massive understanding of each other in just one round-trip delay - plus just a few years for decoding the message and chatting with the AI bot. In essence, if we have good AI (I don't think that's unreasonable in the next 50 years) - and enough bandwidth to transmit it somewhere - we can avoid most of the difficulties of that round-trip delay by more or less sending one of our AI citizens to their planet at the speed of light and having them send us an AI citizen in return.


 * With such a scheme, one could hope to get a reply within a plausible life-span...but only if there is enough bandwidth between the civilizations to permit a few terabytes of information to be transmitted over a period of a couple of years. SteveBaker (talk) 15:20, 2 March 2016 (UTC)


 * But that has nothing to do with bandwidth, does it? My_Son,_the_Physicist is a short story by Asimov that discusses the delay issues. His solution is simple: just keep talking. SemanticMantis (talk) 22:20, 1 March 2016 (UTC)


 * I like my approach better than Asimov's! SteveBaker (talk) 15:20, 2 March 2016 (UTC)


 * I am assuming the computing meaning of "the rate of data transfer", or, more generally, Steve seems to be asking about the total amount of data transferred. To transfer the most data, they would need to allocate a lot of power on a narrow beam transmission, which would allow us to pick up many "bits" at once, each sent over a very narrow frequency range.  But, if they can't allocate much power, due to having to divide it up on signals sent in every direction, then the signal we get will be too weak, so they will have to use wider frequency ranges in the hopes that we will notice it at all. StuRat (talk) 00:07, 2 March 2016 (UTC)


 * Yeah - amount of data (in bits or bytes) transmitted per second. I agree that doing this with an omnidirectional signal is bad - but let's assume they detect Earth using the Transit Method and are able to detect the presence of a pre-industrial civilization here by looking at a spectrogram of our atmosphere...and so they know where to beam their message when they figured this out 100+ years ago. SteveBaker (talk) 15:20, 2 March 2016 (UTC)


 * StuRat, you're assuming the alien experience would likely be no different from the human experience. By definition, we cannot make such assumptions.  --   Jack of Oz   [pleasantries]  23:20, 1 March 2016 (UTC)


 * Which assumptions do you mean ? That their energy supply is limited ?  That's a limitation of physics, not just culture. StuRat (talk) 00:08, 2 March 2016 (UTC)


 * Until then, they are only likely to send out very simple "Here we are" messages that can be broadcast in all directions. What is "likely" from a human perspective may not be so from the perspective of any of the trillions of alien civilisations that must surely exist.  Our knowledge of physics has expanded enormously just in the last 50 years.  We must know pretty much everything worth knowing by now, eh? No, the more we learn, the more we realise we have hardly even begun to scratch the surface.  From the perspective of some alien cultures, we must still be like the early C20 scientists who warned that any motor vehicle that travels any faster than 25 mph would kill all its passengers.  Or that travel to the moon and planets is scientifically impossible. --   Jack of Oz   [pleasantries]  09:12, 2 March 2016 (UTC)


 * In the interests of factual accuracy, I should point out that, although Dionysius Lardner may not have been the greatest scientist ever, he never actually said that. Tevildo (talk) 21:16, 2 March 2016 (UTC)


 * I stand corrected. Thanks. But there was a law requiring vehicles to be preceded by a pedestrian waving a red flag to warn people of the inherent danger. Since he could hardly exceed walking pace, this seriously eroded the point of having vehicles.  --   Jack of Oz   [pleasantries]  04:01, 3 March 2016 (UTC)


 * Paying someone to walk a few miles while you conserve your energy and ride along in comfort and style behind them was evidently an acceptable deal to the people who had enough money to spend on a ruinously expensive horseless carriage. SteveBaker (talk) 14:37, 3 March 2016 (UTC)


 * Agreed. We have to realize that, at the time, a car wasn't the same thing as it is now, it was a slow vehicle used to show off how rich you were.  In that context, the law was reasonable, at that time. StuRat (talk) 18:44, 4 March 2016 (UTC)


 * If they send the signal in all directions, versus, say, 1 arc second squared, they would need to use (360×60×60)2 or 1.68 trillion times the signal strength, so it would arrive at the same strength. I can't see how this physics could change with technology.  They could, conceivably send the signal on a narrow beam transmission only to the nearby planets.  Here technology could make a difference, as, for us, moving the antennas to point to new locations takes time, but they might have some way to aim with no moving parts, and even to use one antenna to send multiple narrow beams at once.  In this case, if they only wanted to send data to the nearest 100 planets, they would only need 100 times as much power. StuRat (talk) 18:15, 2 March 2016 (UTC)


 *  I can't see how this physics could change with technology. - Exactly.  Humans can't get beyond human thinking.  That's what makes us humans.  Non-human civilisations are utterly unknown to us, and it's a complete waste of time, let alone a misuse of the Reference Desk, to engage in hypothesising about what they can or can't do.  If the best we can do is send out "Here we are" messages in all directions, do not assume that that is the best they can do. You have no basis on which to adjudge this as "likely". --   Jack of Oz   [pleasantries]  20:52, 2 March 2016 (UTC)


 * Some physics could be wrong, like string theory, but the very well established parts aren't likely to be completely wrong, although they might need a minor tweak here and there. For example, the Earth being around 93 million miles from the Sun.  Maybe we might need to refine that distance out in the 8th decimal place, but it's not going to turn out it's really a trillion miles or a thousand.  Same is true for how a signal decreases when spread out. StuRat (talk) 18:48, 4 March 2016 (UTC)


 * Where do you get the 360? Using the definition of square degree, I get a ratio of 535 billion. HTH. —Tamfang (talk) 06:04, 4 March 2016 (UTC)


 * I used an approximation. I didn't think it would be that far off, though.  Can I see your math ? StuRat (talk) 18:40, 4 March 2016 (UTC)


 * The OP misunderstands the Nyquist rate. The Water Hole is a bandwidth of 246 MHz centered on 3.086 GHz. It could be used for simple DSB data transmission at 123 M bit/s or a high-order Quadrature Amplitude Modulation signal of up to many gigabits per second. The possible data rate is limited not by the radio bandwidth but by the signal-to-noise ratio i.e. the energy per bit. Your intelligent alien probably should have mastered digital modulation methods including Viterbi decoding of convolutional channel coding and FEC to maximise this. Using an unnecessarily wide frequency range with a given transmit power makes it harder, not easier to detect a beacon signal. (Spread spectrum modulations are useful only to an already prepared and synchronized receiver.) AllBestFaith (talk) 02:42, 2 March 2016 (UTC)


 * The most important issue would be the signal to noise ratio, but that's a practical rather than theoretical limit -- it can always be improved by increasing the power of the signal and tight-beaming the signal toward a specific target, assuming the intended recipient is known. Looie496 (talk) 14:28, 2 March 2016 (UTC)


 * So what could we expect? One bit per second?   A megabit per second?   What is the ballpark figure here? SteveBaker (talk) 15:25, 2 March 2016 (UTC)


 * Steve, I don't think we can give you a limit or even a ballpark, but what we could do is show you what the SETI institute is looking for (very very very narrow-band signals). We could apply the philosophical stylings of the Drake equation, rewritten to include bandwidth and range terms, so that we can speak quantitatively about the relationship between detectability probabilities and signal-strength or signal information-content.  It's a lot easier to detect a very low-information signal.  It is a lot harder to prove that an information-dense signal is something-other-than-noise.  Nimur (talk) 17:26, 2 March 2016 (UTC)
 * Clearly there would need to be two signals:
 * Very low bandwidth, "20 prime numbers...listen at xxxGHz...20 prime numbers...listen at xxxGHz"...over and over...repeating maybe once a minute.
 * At xxxGHz - an information-dense signal that's almost indistinguishable from noise that repeats: "This is how to decompress the message...This is how we represent algorithms...Here is an AI chat-bot algorithm...Here is Wikipedia, Use the chatbot to help you to understand it." over and over again.
 * I'm hoping it would take no more than a few months to send one repeat of the full message. But that's really my question.  This only works if you can can send an error-corrected terabyte in under (say) a year.  If it takes a hundred years to send all of that, then this approach isn't so good.  SteveBaker (talk) 15:19, 3 March 2016 (UTC)
 * As a reference, Voyager 1 which is now in interstellar space at a distance of 134 AU (2.00×1010 km) managed 115,000 b/s from Jupiter, half that rate at the distance of Saturn, and as it recedes the last telemetry we are likely to receive from it will be 40 b/s. Wikipedia content is distributed under license(s) that allow humans to re-distribute it but do not expressly grant that right to non-human aliens. It is ominous that the Klingon vocabulary has no translation of "fair use". AllBestFaith (talk) 18:06, 2 March 2016 (UTC)
 * There's nothing in either the CC or GFDL licences that appear to explicitly restricts re-distribution to humans although the GFDL does refer to formats suitable for human modification. Of course both licences are designed to work under human legal systems. However if you're referring to the legal systems of non human aliens and if the non-humans aliens have concepts of intellectual property and if they do recognise human intellectual property rights then there's no intrisic reason why they won't similar recognise the applicability of free content licences. If they dont recognise human intellectual property or don't have such a concept then it would seem likely the licence is moot anyway, they can do what they want with the content. How sentient non-humans aliens will be treated under human legal systems without law changes is an interesting question, if they are largely treated as human then there's no intrisic reason to think they won't be able to take advantage of free content licences. If they aren't then it's not totally clear that they can even get in trouble for intellectual property violations so the issue may be moot. And as for the copy, provided it follows the terms of the licence, there doesn't seem to be a reason for it to be destroyed. If my cat accidentally prints out something without the permission of the copyright hold (e.g. something even I can't print out), potentially no one will get in trouble but the copy would probably still have to be destroyed. If my cat accidentally prints out a copy of a wikipedia article and manages to comply with the licence in the process, there doesn't seem to be a reason why the copy of the article would need to be destroyed. P.S. IANAL and this is not legal advice. I recommend and aliens and cats consult a lawyer if they intend to do anything related to intellectual property. P.P.S. Of course I'm only talking about redistribution. If aliens want to contribute to wikipedia whether their contributions will be protected or not is a relevant question although all it means is we could treat their material as if it were in the public domain. Derivatives carried out on alien planets under alien legal systems is a more interesting question. Even if the aliens allow redistribution it could be any derivatives will add serious complications. If we want to reimport their content it may get particularly tricky if there is some recognition of their intellectual property rights, particularly if their legal systems impose added conditions or allow them to ignore our rights. Nil Einne (talk) 21:35, 2 March 2016 (UTC)
 * When representatives of life on Earth reach a consensus that the risk of enlightening aliens (of unknown intentions towards us, and possibly overestimated present knowledge of how to do us harm) is an unproblematic way to encourage friendly reciprocation, feel free to broadcast Wikipedia contents such as Nuclear weapon, Biological agent, War and "how to kill large numbers of human beings indiscriminately" to every planet. AllBestFaith (talk) 01:20, 3 March 2016 (UTC)
 * What does that have to do with licence issues? While the latest CC (which we don't use although could be used for redistribution of our content if people wanted to), does deal with a few non copyright issues, it's mostly still intellectual property issues with a few mot stuff like moral rights thrown in. In any case your original question was about non humans redistributing the content, not humans redistributing the content to non humans which definitely doesn't seem to be something the licence limits. There may be non licence legal considerations, but I'm not sure why you brought up licencing issues if you wanted to consider non licence issues. And it seems unlikely any licence is going to affect these legal considerations if they exist. Also the current state of human politics strongly suggests even for non licencing issues, you will not need consensus of life on earth (and I'm not sure how you get consensus of cats and dogs and stuff anyway), you will not even need consensus of humans. Heck in quite a few countries you probably won't even really need consensus of the citizenry there. (I'm not convinced there is actually any country where you're explicitly forbidden from broadcasting to aliens. Although quite a few countries do require you get a licence for most forms of high powered broadcast so technically a licence could be denied if that's your plan. I'm not conviced this is likely in quite a few countries though as the law generally relates to whether or not you're causing inteference problems for others. There are of course countries where broadcasting is more strongly restricted based on content although even in this case the main consideration tends to be other citizens of that country.) Whether or not you should is even more off topic than the original licence issue. Note also, even if there are licencing issues, this only applies to content under that licence. Licencing issues are not going to arise for sending public domain content such as anything produced by the US federal government, or the Encyclopædia Britannica Eleventh Edition etc etc. Perhaps most significantly, as I think this discussion has highlighted, it's fairly likely anyone capable of sending the signal given the current state of technology would have enough funding that they could self finance a project producing information on all the areas you highlighted which aren't sufficiently covered by public domain sources. It would still lack the breadth of wikipedia e.g. on extramarital affairs of various footballers or the dumb things various politicians have said, or what happened in the 18th hour of season 3 of 24 or whatever but how important this would be is unclear. Nil Einne (talk) 14:45, 3 March 2016 (UTC)
 * My idea to send something-like-Wikipedia-with-appropriate-licensing-for-aliens is that we don't know in advance what the aliens will want to know. Maybe they are more interested in how the Japanese name their railway stations or on the sexual proclivities of humans more able to propel a spherical projectile into a predefined volume of space using only the limbs more normally assigned to propulsion than fine object manipulations?  Perhaps that's more important to them than whether we know the properties of palindromic base-10 prime numbers?  How we would we know?  They're aliens for chrissakes!
 * That's why a 200-year question...answer cycle won't work - and why Asimov's idea of "just keep talking" is inefficient if something that we said is fundamentally not understood or misinterpreted by the aliens. So that's why I'd send a big block of human knowledge and an AI bot that knows how to interpret and translate it in a human-like way.  The bot would have at least as much knowledge as any astronaut we might ever manage to send - and could (ideally) be able to provide a very human spin on it and explain areas of confusion or difficulty.  Getting something similar in return would be an amazing gift for humanity - and it could be done with just one round-trip radio signal.  However, it stands or falls on whether there is enough bandwidth to be able to send all that software code and data in a reasonable amount of time.  Hence the question. SteveBaker (talk) 15:08, 3 March 2016 (UTC)
 * @Nil Einne, I did not ask a "question about non humans redistributing the content" but am grateful that you give your speculations about that side issue. Laws against Crimes against humanity have always been enacted after significant damage has been done, and in the category "crimes against earth life" we have so far little protection beyond some haphazard Environmental laws. So to caution you and Baker in your headlong rush to active SETI i.e sending signals into space in the hope that they will be picked up by an alien intelligence, and pending constitution of some responsible Authority, I give notice that I do not grant a right to broadcast life-critical data that belongs to my earth race from this my small precious planet, not even just because you think you can. My cat endorses this message. AllBestFaith (talk) 10:47, 5 March 2016 (UTC)
 * So, you deny me my right to free speech when I'm talking to non-humans? I dunno about that!  :-)  SteveBaker (talk) 19:00, 5 March 2016 (UTC)


 * So...er...bandwidth? SteveBaker (talk) 15:08, 3 March 2016 (UTC)
 * The interstellar medium produces random artifacts in radio transmission, which we can characterize by looking at distortions in pulsar signals. For a GHz carrier frequency and a distance of ~1000 light years, interstellar medium distortions are estimated to limit the useful signal to about 1 kHz.  One can of course get larger bandwidth at shorter distances.  There may also be ways to measure and partially compensate for ISM distortions with the right engineering, but I wouldn't expect to ever get huge bandwidth at interstellar distances.  On the other hand ~1 kHz gets about 10 GB per year, which isn't a bad start.  Dragons flight (talk) 16:33, 3 March 2016 (UTC)


 * Assuming aliens have had literal millennia to plan communications, I suspect what one will see first is a great booming signal with some simple math and a very low bit rate (~1 bit / s) to get our attention. Related to that, or perhaps modulated on top of that, might be a simply encoded signal (~10 bits/s) with basic instructions for where to find a better signal and how it is encoded.  Perhaps that signal gets you ~1 kbit/s using Arecibo-type technology, and then you can really start to do interesting things.  With that signal, perhaps they tell you how to build a super receiver with advanced technology to counter the problems of interstellar transmissions, and find a magical >100 kbit / s transmission, which might finally be the real signal.  Even if it takes years to iterate through the signals it could still be accomplished in much less than the round-trip signal time to most nearby stars.   Dragons flight (talk) 19:14, 3 March 2016 (UTC)


 * Thanks! That's the answer I was looking for.  I agree that you'd need a simple, low-bandwidth/high-energy message on one frequency that would point towards a high-bandwidth message on some other frequency that would contain all of the content.  There is an argument for doing it in several stages - (as in Contact (novel) where there were three layers - the initial repeating prime number sequence, the "primer" and then the description of how to build "the machine").
 * 1 kbit/sec is annoyingly right on the edge of making the idea work! It would take decades to maybe a century to send the package that I'd want to send...which is faster than the likely round-trip delay - but not by much.  It might just be quicker to ask them what they want to know and send just that than it would be to send a representative set of everything unconditionally.  Of course there is nothing stopping you from doing both.
 * Ten times faster than that would make doing what I'm thinking of work very well, ten times slower would make it clearly useless. 1 kbit/sec is just annoying! :-)
 * Oh well...I guess we'll have to wait and see! SteveBaker (talk) 20:25, 3 March 2016 (UTC)
 * Now you just sound greedy. What, you want to send RAW images in 24-bit color, or what?  1 kbit/s, 1 bit/s, 1 bit/day, there's plenty you can say.  Remember Under the Eye of the Clock. --Trovatore (talk) 20:34, 3 March 2016 (UTC)


 * Well, I want to know if sending an AI computer program (let's guess that's about 1Gbyte) plus a big chunk of knowledge (and I use Wikipedia as the kind of thing I have in mind - that's 10Gbytes of compressed text plus around 20 Tbytes(!) of compressed pictures, sounds, videos, etc). So the size of the media files from WikiCommons dwarfs everything else.  If we could just not bother with them, then even at 10Gbytes/year, we're done in a year or two...but at that speed, the media files push that up to a thousand years to transmit it all.  If we employed a few thousand people, we could probably prune the 20Tbytes of media considerably - but it would be tough to know what to leave out, and I'm sure we'd still need a hundred years to send it.  We could toss in a copy of the human genome (~1Gbyte) for just a month of extra transmission time - but the 10,000 Tbytes it would take to send the library of congress would be entirely unreasonable.
 * The nearest thing we have to a computer that could answer most of the alien's questions might be IBM's Watson (computer) - which knew enough to beat the best Jeopardy! players in the world. It used a 4 Tbyte database to do that, so sending a copy of Watson would take 400 years - and that's without any pictures at all.
 * SteveBaker (talk) 18:26, 4 March 2016 (UTC)


 * Also keep in mind that you can't simply send a computer program, you also have to convey a description of the computer required to run it and all the other technical details we take for granted. Can't exactly send a JPEG without explaining how to interpret a JPEG.  I imagine a lot of bytes being expended in the early days in order to build a basis for efficient communication.  Dragons flight (talk) 21:10, 4 March 2016 (UTC)
 * Well, you have to explain what the bytes that make up the program are intended to do. You don't need to describe the computer itself.  For example, in a One instruction set computer, there is only one operation that's repeated over and over. So all that needs to be explained is how that one instruction behaves on the available data.  It seems plausible that this could be conveyed in the language of arithmetic, perhaps with a couple of pictures.  Once you've conveyed that very simple instruction set, you can transmit a short program written in that horribly restrictive form that interprets some higher-level/more-compact programming language.  One would expect an analysis of the 'interpreter' to allow reasonably intelligent aliens with some kind of programmable computer to translate the AI program into something they could run efficiently on their computers.  This doesn't seem difficult to me providing we can convey a representation of a number, and the symbols we use to convey arithmetic operations.  Sending 'demo' programs that calculate prime numbers or the digits of pi or something would greatly aid in helping them to bootstrap the entire process. SteveBaker (talk) 18:56, 5 March 2016 (UTC)
 * 1 kbit/sec might be annoying to you but that is the auto-centric view point. The more important issue is the quality & potential of the information received. Example: The Dead Sea Scrolls were transliterated at several orders of magnitudes slower than 1 kbit/sec. That seems to be the trouble with the under seventy year olds today. They want it and they want it now! And like Veruca Salt they get their knickers in a twist if they can't have it instantly. In day of old (yore), a stone mason laying the first course of the  foundations to a new cathedral would not expect to be amongst the living when his son finally topped it off on completion  60 years later. Patience, young grasshopper. --Aspro (talk) 18:49, 4 March 2016 (UTC)
 * Those stonemasons believed that their reward was from God - hence they'd get what they wanted long before the cathedral was finished. My reward would be knowing the mind of an alien species.  It's not much use to me if it arrives long after I'm dead!  That's not to say that we can't do things that take longer than a human lifespan - but figuring out a way to do this WITHIN a human lifespan seems like a good thing to do if it can be done. SteveBaker (talk) 21:07, 4 March 2016 (UTC)

US midwest bronchitis outbreak
When there is an outbreak of such diseases as influenza or whooping cough, one hears news coverage with statements from CDC or state health departments. In January and February of 2016 in the midwestern US, there has been a severe outbreak of bronchitis, with prolonged coughing, wheezing and gurgling in the lungs and prolonged fever. Some are hospitalized or given antibiotics if it develops into pneumonia, although the primary infection seems to be viral. It seems to be bronchitis initially without manifestation of the common cold, sore throat, sinus infection or tonsillitis.The incidence seems high, such as all of one's coworkers, numerous neighbors and church members, but I've seen no news coverage. Does any US agency or do state agencies collect and tally information about mass infections such as I described? I can only find a March 1 news story in The Post and Courier of Charleston that says "..anecdotal evidence from primary care providers suggests that upper respiratory illnesses are raging this winter. Dr. Bo Machado is the medical director of Health First, a network of four primary care and urgent care offices in the Charleston area. He said Health First has treated hundreds of patients with this virus, and there’s not much his staff can do for patients except help ease their symptoms because the virus doesn’t respond to antibiotics. “Instead of lasting three days or five days, it’s lasting 10,” Machado said. “And because of that, it’s spreading to more people because it’s around longer.” Why doesn't the CDC analyze it and see what the "virus" is or what the predominant viruses are? It seems like something might have mutated and become more virulent. .Edison (talk) 21:22, 1 March 2016 (UTC)


 * I looked into info for Ohio. Here are reporting requirements for infectious disease there. Bronchitis does not appear to have any mandated reporting at the state level. However that doesn't mean they wouldn't know if there were an outbreak. Disease statistics are prepared monthly by the state of OH, and can be seen here, and there is also a phone number/email address for the Bureau of Infectious Diseases that you can contact for more info. I just picked OH at random because I know a few things about their system, I suspect other states have similar infectious disease reports, summaries, and official contacts. I am not currently aware of any non-state and non-federal regional body that would collect and report infectious disease data for the midwest. But I do think you can contact an official body in your state for more specific info, if any is available.  SemanticMantis (talk) 22:04, 1 March 2016 (UTC)


 * Bronchitis that cleared up after ten days would be an improvement on the usual. As the NHS says "In most cases, bronchitis will clear up by itself within a few weeks without the need for treatment.", and as our article says "Acute bronchitis usually has a cough that lasts around three weeks". DuncanHill (talk) 13:57, 2 March 2016 (UTC)