Wikipedia:Reference desk/Archives/Science/2017 April 21

= April 21 =

Mars the Orange Planet
Mars looks orange rather than red. Why is Mars is called the Red Planet and not the Orange Planet? Could it be due to lingual reason or is it just easier to say according to a forum I saw? Yeah, I know Mars looks reddish as seen in the sky on Earth (that could've been the root origin of the Red Planet), but it looks orange when seen from telescopes or from spacecraft near it. Planet Star  00:10, 21 April 2017 (UTC)
 * We've been calling it the red planet longer than we've had telescopes. Medieval and classical astronomical works describe it as red.  Ian.thomson (talk) 00:13, 21 April 2017 (UTC)
 * Also, the word orange as a colour descripion is of relatively recent origin. (First used in English in 1512.) Mars has been associated with war and blood for millennia. {The poster formerly known as 87.81.230.195} 90.217.249.244 (talk) 00:31, 21 April 2017 (UTC)
 * Interestingly enough, the planets from Mars to Neptune approximately follow the spectrum, with no green. Mars is red, Jupiter is orange, Saturn is yellow, Uranus is cyan, and Neptune is blue. Two questions are (1) why is there no green planet and (2) do you think planet 9 will be violet?? (For the latter of these questions, it would be nice if official info could be found sometime within 2017.) Georgia guy (talk) 00:38, 21 April 2017 (UTC)
 * You might be interested in Sudarsky's gas giant classification, as a start for searching literature on this. It is predicted that so called "Class V" (as in Class five) Gas Giants could be visibly green. I couldn't find you answer for whether a terrestrial planet could be green. Someguy1221 (talk) 01:40, 21 April 2017 (UTC)
 * Are you suggesting we're living in a gay solar system, Georgia guy? :) --   Jack of Oz   [pleasantries]  05:13, 22 April 2017 (UTC)
 * I'm just pointing out a pattern in planet colors. I didn't even think about that question as something someone would ask me. Georgia guy (talk) 00:52, 23 April 2017 (UTC)
 * There you go then. --   Jack of Oz   [pleasantries]  00:41, 24 April 2017 (UTC)


 * People don't usually argue subtle color distinctions for tiny dots of light. ("Mars is cinnibar?  You're trippin', dude.  It's more of a burnt sienna.")  The thing that distinguishes Mars and a couple of stars from all the little white dots is that they're slightly redder, so "red" seems like a good thing to call it.  See also psychological primary color.  Someone please also link that theory where, if a language has a word for green, then it has a word for blue, or however it goes. --Trovatore (talk) 00:42, 21 April 2017 (UTC)
 * Basic Color Terms: Their Universality and Evolution. -- Jayron 32 01:05, 21 April 2017 (UTC)
 * That's it, thanks. --Trovatore (talk) 04:15, 21 April 2017 (UTC)


 * I believe the color of Mars is mainly from iron oxide (rust). Would you describe that as orange or red ? StuRat (talk) 05:12, 21 April 2017 (UTC)
 * No, I'd say it's brown. But we're supposed to provide references, so, using onelook.com, let's see what some dictionaries say. Rust, the substance, is:
 * "reddish" according to Merriam-Webster
 * "reddish- or yellowish-brown" according to Oxford
 * "reddish-brown or reddish-yellow" according to American Heritage
 * "brown" according to Collins (There, see, I was right!)
 * "red" according to Macmillan
 * But, like gray, brown is a color that can only be perceived by contrast with something brighter (see Brown). Since a planet is seen against the night sky, it cannot be perceived as brown; if its surface is brown it will appear red, orange, or yellow. --76.71.6.254 (talk) 05:56, 21 April 2017 (UTC)


 * Tovator and 76.71 have it. It's hard to make a photograph that captures the experience of looking up at faint pinpricks against a jet black sky, but some of the photographs on NakedEyePlanets.com are passable.
 * Mars looks noticeably red compared to its surrounding stars. (Moreso with naked eye than with those photographs.)
 * Even in these photographs it's easy to lean in close to your monitor and contemplate the exact color, but in real life, when it's just a shimmering dot close to the edge of your vision... Well, with my eyes, I feel proud that I noticed it was red. ApLundell (talk) 14:37, 21 April 2017 (UTC)


 * Different people see borderline colors differently (citation needed). I always see Mars as orange (OR) with my naked eye. As for why it might be called red even if everyone saw it as orange, sometimes (citation needed) orange is subsumed in red—see for example redhead. Loraof (talk) 15:34, 21 April 2017 (UTC)


 * There's a difference in shade depending on if it's very bright like the August 2003 "perfect opposition" (best opposition for 284 years) or minimum brightness (where it approaches the dimness at which the naked eye doesn't have color vision) and also how close to the horizon it is and how hazy the sky is. Have you seen it under all these conditions? Sagittarian Milky Way (talk) 00:25, 22 April 2017 (UTC)


 * Like the Red Planet, the robin redbreast typically has orange plumage. --catslash (talk) 15:57, 21 April 2017 (UTC)


 * I find the premise absurd. I have added a true color image of the planet.  If I were to characterize this as anything other than red, I would call it i peachy-red, and find it in no way orangish. μηδείς (talk) 02:22, 22 April 2017 (UTC)
 * But when I hold my set of coloured pens next to your image, it is almost exactly the same colour as the orange pen, and nothing like the red one. Wymspen (talk) 14:24, 22 April 2017 (UTC)
 * There needs to be a color called rorange. Sagittarian Milky Way (talk) 16:22, 22 April 2017 (UTC)
 * I just held up an actual fruit and a red sharpie pen to the image. It is certainly closer to an unsaturated red than orange to my eyes, but then our computer settings may be off.  I'll certainly grant that Mars is not FF0000 in the RGB color system, but I have never seen an image that has made me think the planet looked orange. μηδείς (talk) 02:12, 23 April 2017 (UTC)
 * Careful, most "True color" images from space instruments are not quite true color. (And they often don't match each-other.) In this image's case the red channel is coming from OSIRIS's "orange" filter. which is 607-691nm, which is not the same as cameras you might get from your phone's camera. It makes for good images, but without knowing the exact details of how the image was processed, I wouldn't use it to win a debate. ApLundell (talk) 09:23, 23 April 2017 (UTC)

Constraint vs Restraint (Physics and Maths)
Dear Science Reference Desk,

"constraints" and "restraints" are terms used interchangeably, but it seems they have a clear distinction in Physics, Maths, ..., that I could not find on en.wikipedia.org.

Some help from the web:

http://pd.chem.ucl.ac.uk/pdnn/refine2/overview.htm

http://ambermd.org/Questions/constraints.html

This question fits the Maths Reference Desk as well.

Thank you for the consideration! 134.147.45.13 (talk) 08:11, 21 April 2017 (UTC)


 * I think Wikipedia makes the distinction very clearly. See the disambiguation pages Constraint and Restraint. Loraof (talk) 15:42, 21 April 2017 (UTC)


 * The disambiguation pages do not clarify the difference in Physics or Maths. For instance, there is no Restraint in the subject I am referring to, albeit the Physical restraint... but it's not Physics! :) --134.147.45.13 (talk) 09:54, 27 April 2017 (UTC)

Scientific knowledge
What is always more powerful and more scientific knowledge, is it special knowledge or general knowledge?--109.252.29.219 (talk) 10:35, 21 April 2017 (UTC)
 * Does special justice always being more juditional than general justice?--109.252.29.219 (talk) 11:09, 21 April 2017 (UTC)
 * Does extraordinary justice always being more juditional than other justice?--109.252.29.219 (talk) 11:31, 21 April 2017 (UTC)
 * Define those words you're using. ←Baseball Bugs What's up, Doc? carrots→ 12:19, 21 April 2017 (UTC)
 * I’m interesting, does special justice always creating a special knowledge and does general justice always creating a general knowledge in science?--109.252.29.219 (talk) 12:30, 21 April 2017 (UTC)
 * What are you talking about? Do you have any examples? ←Baseball Bugs What's up, Doc? carrots→ 12:33, 21 April 2017 (UTC)


 * I'm afraid your command of the English language is not good enough to express yourself such that people can help you find answers to your questions. It's clear your native language is something other than English.  If you tell us your native language, we can direct you to help in your own native language.  -- Jayron 32 13:15, 21 April 2017 (UTC)


 * I just noticed that the Languages on the reference desk aren't filled in. It would be nice so we could easily direct this user to the Russian reference desk. 209.149.113.5 (talk) 13:18, 21 April 2017 (UTC)


 * They are on the left side of the page Reference desk. Not sure it will help.  If this is who I think it is, he's a regular customer here and we should probably shut this thread down; it never goes anywhere in the years he's been asking these sorts of questions.  -- Jayron 32 13:43, 21 April 2017 (UTC)
 * This series lacks the "is been" constructions typical of that regular customer. —Tamfang (talk) 23:55, 23 April 2017 (UTC)

Thanks. To my mind, extraordinary justice does always creating special knowledge which always being more juditional than general knowledge.--109.252.29.219 (talk) 13:28, 21 April 2017 (UTC)
 * I'm sorry, but this isn't understandable as a statement in English. I suggest trying to see if there's a help desk on the Russian wikipedia. Shock Brigade Harvester Boris (talk) 13:34, 21 April 2017 (UTC)
 * The answer lies in the eye of the Beholder. Classic Intellectuals have always voted Philosophy aka "general knowledge" "King of Science". A General would probably choose "Rocketscience" as most powerfull instead. --Kharon (talk) 13:42, 21 April 2017 (UTC)
 * Is special troll different from general troll? Where can I turn to have my language understood? Are there any English-speaking forums? Bus stop (talk) 13:57, 21 April 2017 (UTC)


 * I think we've seen enough here. -- Jayron 32 14:10, 21 April 2017 (UTC)

Specialty or profession
What is always more important the specialty or profession?--109.252.29.219 (talk) 18:24, 21 April 2017 (UTC)

Identifiable whisperers
Whispering tells me "... there is currently no known possibility to use speech recognition successfully on a whispering person, as the characteristic spectral range needed to detect syllables and words is not given through the total absence of tone".

So, how come we can (usually) quickly identify a whisperer whose normal voiced speech is already known to us? Not just family and friends, but I'd bet that if I heard a recording of, say, John F. Kennedy whispering something, I'd know immediately it was he. What is it that we have that voice recognition technology has not yet achieved? --  Jack of Oz   [pleasantries]  23:41, 21 April 2017 (UTC)


 * Really? I can't. Maybe it's just me. I honestly can't distinguish whispers. Usually, the content and speaking style are more important than the voice. 50.4.236.254 (talk) 00:44, 22 April 2017 (UTC)

There are two sources for that statement, one written in 2011, and the other undated. I note that when I search Google Scholar for speech recognition via whispers, I find this is a very active field of research, with hundreds of papers published on the subject every year. Certainly, there are many experts who think it is possible to do this, and they are trying to figure out how. This is totally outside my field of expertise, so I wouldn't even know who to begin citing. Someguy1221 (talk) 02:47, 22 April 2017 (UTC)


 * I suspect the signal to noise ratio is relevant. The timbre of a voice might be lost to the hissing characteristic of a whisper.  I remember reading that thieve's cant avoided voiced sounds in order to be less noticeable or comprehensible to unwanted listeners. μηδείς (talk) 02:08, 23 April 2017 (UTC)
 * Yep, and presumably those listeners would (in general) not know the thief and would never have heard their normal voiced speech. I'm talking about speakers who are known to the listener.  Try it out among your household or friends.  Get a few people together, close your eyes, and see if you can't recognise who's whispering at any moment.  I'm sure most people have this recognition capacity.  I have a significant hearing loss and I can certainly do it (assuming no external sounds to confuse the ear). Why can't some artificial technology do the same?  --   Jack of Oz   [pleasantries]  00:49, 25 April 2017 (UTC)


 * Well, we know fusion is possible. Maybe the technology hasn't gotten there yet?  Flight and light bulbs were also imagined before they were accomplished. μηδείς (talk) 14:23, 25 April 2017 (UTC)


 * Er, I started out by quoting the bit that says technology can't currently do it, and now you're telling that's because technology hasn't got there yet. Who knew?  :)  --   Jack of Oz   [pleasantries]  19:56, 25 April 2017 (UTC)