Jump to content

Wikipedia:Reference desk/Archives/Science/2015 January 20

From Wikipedia, the free encyclopedia
Science desk
< January 19 << Dec | January | Feb >> January 21 >
Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.


January 20

[edit]

After how many hours could you wipe off a butter knife and reuse it?

[edit]

Wipe very thoroughly (like one more time after no butter is visible on the paper towel anymore), but without washing it. Sagittarian Milky Way (talk) 00:04, 20 January 2015 (UTC)[reply]

My butter knife has no crevices or cracks. I don't want an off/rancid taste, though. I always wash it if it's been four hours, I wonder if I could do longer. Sagittarian Milky Way (talk) 00:08, 20 January 2015 (UTC)[reply]

Depends on the temperature and personal taste. I often don't even bother refrigerating butter unless the room temperature has been driven up past the usual by the weather. Wnt (talk) 00:14, 20 January 2015 (UTC)[reply]
Yes but a thin smear will oxidise somewhat rapidly in warm weather. SM, just because some cupid stunt posts a question every time a breeze blows in one ear and out the other, it doesn't mean you have to. Let's try and make the refdesk better rather than worse? Greglocock (talk) 00:54, 20 January 2015 (UTC)[reply]
If you wipe it thoroughly, I can't imagine enough rancid butter would remain to be detectable by taste. StuRat (talk) 05:39, 20 January 2015 (UTC)[reply]
Nope. A wipe is as good as a wash. Peanut butter is another story, but even then, a thorough wipe wouldn't be thorough if the knife wasn't clean. Yesterday, I reused the same dirty PB(&B)&J knife for another, six hours later. No wipe. I lived (so far). InedibleHulk (talk) 05:53, 20 January 2015 (UTC)[reply]
Soap isn't that expensive. Seriously, if you can't afford the drop of soap necessary to clean the butter knife, the money you are spending on your internet bill probably is too much, and you wouldn't be posting here. --Jayron32 02:22, 21 January 2015 (UTC)[reply]
Ah well, it takes forever to wash. Maybe the pipes make the water harder. Sagittarian Milky Way (talk) 04:26, 21 January 2015 (UTC)[reply]
My problem is that if I use detergent, no matter how much I rinse the dishes, I seem to taste it still. So, I prefer to only rinse my dishes, which requires avoiding greasy foods, which is probably a good idea anyway. Tomato sauce also seems to act as an emulsifier to keep any grease from sticking. StuRat (talk) 05:39, 21 January 2015 (UTC)[reply]

Species summary format

[edit]

Hello Wikipedia,

Just a question. I very much like the summary boxes that accompany many entries for species of organisms. The 4 features addressed ( 1- Temporal Range, 2- Conservation Status, 3- Classification & 4- Geographic Distribution) are excellent choices. How was format for the boxes arrived at, and is there any incentive to get those boxes that are not quite a complete up to speed?

Many thanks A

Platypus Temporal range: 9–0Ma PreЄЄOSDCPTJKPgN Miocene to Recent Wild Platypus 4.jpg Conservation status

Least Concern (IUCN 3.1)[2] Scientific classification Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Monotremata Family: Ornithorhynchidae Genus: Ornithorhynchus Blumenbach, 1800 Species: O. anatinus Binomial name Ornithorhynchus anatinus (Shaw, 1799) Distribution of the Platypus (Ornithorhynchus anatinus).png Platypus range (red — native, yellow — introduced)AigaBus (talk) 00:50, 20 January 2015 (UTC)[reply]

In general, such issues are decided by discussions between editors, leading to WP:CONSENSUS. For this particular example, see Template talk:Taxobox - note that it has 30 pages of archived discussion. If you want to suggest improvements to this sort of thing, you can post a message to the talk page of the template in question. Tevildo (talk) 01:05, 20 January 2015 (UTC)[reply]
WikiProject Tree of Life would be the group coordinating such efforts. Rmhermen (talk) 02:29, 20 January 2015 (UTC)[reply]

Dregs in Cherry Zero and Vodka

[edit]

I get a few specks of dregs at the bottom of my glass whenever I mix Coca-Cola Cherry Zero (with Aspartame) and Vodka. I used to drink plain Coke and vodka years ago, and don't remember there being any dregs. Any suggestion as to what might be going on here? Thanks. μηδείς (talk) 01:39, 20 January 2015 (UTC)[reply]

This is likely some form of Precipitation (chemistry) due to the change in solvent. The substance coming out ought to be hydrophilic. If you filter some through paper you can see if it's brightly colored, and I predict you can dissolve it again in water (perhaps it will take some time). If that fails we may be back to the drawing board. Presumably it is an ingredient not present in something longstanding like rum and coke, and specifically in the cherry zero formula since I assume the vodka is pretty boring chemically (if it were in the vodka it would redissolve in ethanol, not water). Wnt (talk) 13:28, 20 January 2015 (UTC)[reply]
The precipitate is brown, the same hue as the Coke, but more saturated. I'll try seeing if it dissolves again in water. I'll get back, although this thread will probably be off the board by the time I next perform the experiment. I had though perhaps there was a known reaction between aspartame and alcohol, perhaps in the presence of malt coloring. BTW, it doesn't appear crystaline, but I have never dried it, and we're looking at at a few fragments no larger than grains of kosher salt. μηδείς (talk) 16:57, 20 January 2015 (UTC)[reply]
Not everything precipitates as crystals, especially when the change in solvent is abrupt. Getting macroscopic crystals can be a high art in the case of crystallization of large, complex, flexible molecules for applications like X-ray crystallography. This might be a simpler problem, something that can be fixed simply by dribbling in the vodka slowly while swirling. On the other hand it's possible that the substance is a complex mixture, like caramel color (that should be in rum and coke but maybe the pH or other features of the cherry formulation is less conducive to its solubility) Wnt (talk) 21:04, 20 January 2015 (UTC)[reply]
I usually put the ice in first, so it doesn't splash, then the vodka, then slowly pour the Coke into the vodka, since this prevents its foaming over. If I understand you correctly, I'd have to try that in reverse. μηδείς (talk) 17:51, 21 January 2015 (UTC)[reply]

What kind of cat is this?

[edit]

I saw a cat in the middle of the road, so I stopped and tried to chase it off. It followed me and rubbed and purred, so I picked him up and put him in the car. After all, I don't want to run over a cat. I asked at all the houses within 2 miles, and nobody recognized him. So I took him home. He was filthy and bony, but I gave him a bath and started feeding him. Turns out he's a 6 month old kitten. But other than that, I know nothing about him. So, what kind of cat is he, or what mix, and are there any health issues specific to that breed/breeds I should watch out for? I'm assuming he's a plain DLH, since most strays are, but I just wanted to make sure. He's already been to the vet, but I forgot to ask the breed. http://imgur.com/a/vZdKq/embed#0 --Borat is very nice (talk) 01:09, 20 January 2015 (UTC)[reply]

They do have a way of wriggling into your heart, don't they ?
Not sure about the breed, but it looks like a longhair. Longhair cats need extra care, like frequent brushing and occasional trimming, to prevent their fur from becoming matted or causing them fur balls. StuRat (talk) 05:34, 20 January 2015 (UTC)[reply]
Like you say, most strays don't care about keeping their lineages pure and their traits by-the-book. No cat likely does, some just go along with their owner's fancies. You have a mutt. Those light splotches aren't going to win him any points in a formal beauty contest, but he's cute, and having unrelated parents is generally a health bonus. Granted, there's a lot about genetic makeup that a picture can't show, but probably safe to assume he just needs regular cat treatment. Some longhairs never get matted, and cough up their hairballs with ease. Brushing's still good if you don't want to clean up the hairball, and most like the contact. InedibleHulk (talk) 07:03, 20 January 2015 (UTC)[reply]
Good, I just wanted to make sure he wasn't mixed with any breeds that had specific health problems, like Persians with their breathing issues or the vision problems of Siamese. As long as he's a mutt that's fine :) I noticed his face was kind of flat compared to my other cats so I was worried he might be part Persian, but as long as its not enough to cause problems I'm happy. --Borat is very nice (talk) 17:13, 20 January 2015 (UTC)[reply]
@Borat is very nice:, looks like a nice kitty, good luck! You might be interested in Cephalic_index_in_cats_and_dogs, Brachycephalic_syndrome, and Cephalic_index#Cephalic_index_in_animal_breeding - this tends to be much more of a problem in dogs than in cats, and in general there are also far fewer true-breeding breeds of cats than dogs. So longhair mix is the best anyone other than an in-person vet can say, and I don't think it's nose looks particularly short anyway :) SemanticMantis (talk) 18:05, 20 January 2015 (UTC)[reply]
Borat is very nice: Though (as others have noted here) breeds tend not to be as distinct in felis catus as in many other domesticated species, the phenotype of your new pal's coat technically define him as a "red" medium-longhair tabby-mix. I know, a mouthful. But these distinctions are largely superficial as regards the lines of your inquiry (heritable conditions and health complications). Other than the mild malnutrition which you referenced yourself the only potential health issue that can be deduced from those photos is that which others have touched upon -- grooming issues and the occasional hairball or minor GI obstruction (and these are usually preventable, should your cat prove prone, with the use of a petroleum-jelly product made specifically for this purpose).
I will say also that (while I've never been able to find much in the validation of this claim and am skeptical of it as someone versed in phylogenetics) you will find no shortage of veterinary workers who will insist that reds (that is, orange cats) tend to be amongst the most affectionate, inquisitive, sociable (and socially intelligent), and relaxed cats -- and they generally are regarded as particularly bright as well. Of course, they are also said to be more rowdy and energetic as a general rule. I'm dubious on all counts, but I will say that I ended up with one of my own in circumstances that, pretty much word-for-word, mimic the description you gave of how you came by this fellow, and the average stray is just not that friendly. Anyway, mine turned out to be one of the most truly fascinating creatures I have ever known, with behaviours and mental capabilities I never expected to observe in a cat, and a general disposition that's about as affectionate and full of character as you can possibly imagine -- I hope you can expect much the same.
If you are concerned about getting a leg-up on potential health complications (as you seem to be), I highly recommend this text as a primer and general reference; it's written with a fair degree of physiological detail, but remains accessible to a non-expert and is fairly comprehensive of most all issues your are likely to have to deal with. Of course, whenever there's anything wrong, the vet is always your best resource. Good on you for giving this guy a home after doing your best to ascertain he doesn't already have one; you two are looking like bosom buddies already! Snow talk 08:24, 22 January 2015 (UTC)[reply]
I read "Borat is very nice, though (as others have noted here)", and giggled inappropriately. -- OBSIDIANSOUL 09:20, 22 January 2015 (UTC)[reply]
Haha, yeah, that was honestly sloppy formatting (now corrected). I'm sure he is in fact very nice though. At the very least, deserving of a "I break for small animals" bumper sticker, clearly. Snow talk 09:35, 22 January 2015 (UTC) [reply]
Awww, Nice kitty! 'Borat' might make a good name for it actually! --220 of Borg 15:09, 24 January 2015 (UTC)[reply]

Compass poles reversed

[edit]

Someone broke a rather nice compass by playing around with a magnet and making it spin. Now, north is south and south is north and the owner is quite cross. Is there a way to fix this? Please help. A young child's life hangs in the balance. Anna Frodesiak (talk) 03:49, 20 January 2015 (UTC)[reply]

Grab a magnet and move it over this compass. Make sure you are moving along the needle in the same direction each time. See if the compass points to the North again. I'm pretty sure a similar process is exactly what happened to the compass back then when it started pointing in the wrong direction. I hope I saved this poor kid's life. I don't want to live with this weight on my conscience.--Pathnew (talk) 05:07, 20 January 2015 (UTC)[reply]
Does the compass have correction marks/magnets? If not, it's not that nice :). Checkout compasses for airplanes for their MEL. --DHeyward (talk) 05:20, 20 January 2015 (UTC)[reply]
It worked! (I didn't see correction marks or magnets.) Moving a magnet over the compass just made it spin. So, they held the magnet pole to pole and moved back and forth from the tip of the north arrow to the axis to keep the needle facing one direction. It didn't work and they kept flipping the magnet this way and that. The compass got demagnatized a couple of times and didn't want to point anywhere (which surprised me). Eventually and suddenly, it worked. Nobody knows what they did right. The adults thought it was all terribly interesting. The kid, who was about to trade several allowances for a backward compass was relieved, is now off the hook, and thanks you -- and so do I. :) Anna Frodesiak (talk) 06:12, 20 January 2015 (UTC)[reply]
What a tragedy that this child probably doesn't have an old fashioned CRT type TV set to play with. :) Wnt (talk) 13:23, 20 January 2015 (UTC)[reply]
And I just can't tell whether you're referring to the cool color patterns you could make, or to getting in big trouble after too much playing caused the shadow mask to get magnetized and some of the cool patterns to become, seemingly, permanent! Fortunately it -- mostly -- demagnetized itself after a week or so, and most of the discoloration went away... —Steve Summit (talk) 23:44, 20 January 2015 (UTC)[reply]
Ah, now I see what you mean. I know if you hold a magnet on an iphone, bad things happen. But to kids, this is all BEANS. (Much like Lily Tomlin's "If you hold a baby upside down, it faints.") Anna Frodesiak (talk) 00:03, 21 January 2015 (UTC)[reply]
It depends on how old the TV is. My father briefly had a TV repair shop when I was a kid - and very often, I'd get old TV's that were beyond repair to play with (YIKES!!!). Playing with magnets around those early color TV's was always a lot of fun. With a few magnets, you could tie the picture up in complex knots - and with care, the effect wasn't permanent. But if you got the magnets too close, the TV would remain screwed up even after you removed the magnets. With TVs more than (guessing) about 30 years old, the magnetization effect would be entirely permanent and you'd have to rent an automatic degaussing coil to fix it. Back further than that, you'd need to call on an expert to degauss your TV manually...which turns out to be quite a skilled job! More recently, some computer monitors added a degaussing button that you could use to manually degauss the tube - and then, eventually, they added degaussing circuits that would briefly degauss the tube every time you turned it on. Those don't do a perfect job - which is why it could take days or weeks of turning it on and off again for the tube to finally fix itself. Thankfully, the era of the CRT is almost at an end, and all of these wonders are soon forgotten! SteveBaker (talk) 17:44, 21 January 2015 (UTC)[reply]

Sagittal sutures and scaphocephaly

[edit]

What is the problem with scaphocephaly, i.e. why would it potentially be important to separate an infantile closed sagittal suture? Facebook friends have just learned that their twins will have to have surgery to remove their skulls' closed sagittal sutures, but the sagittal suture article doesn't seemingly mention any downsides to early closing, other than scaphocephaly, and the scaphocephaly article doesn't seemingly mention anything other than a changed head shape. Is it just an æsthetic thing, because a long, narrow, and wedge-shaped head obviously doesn't look very nice, or are there other reasons why scaphocephaly is a problem? Nyttend (talk) 04:32, 20 January 2015 (UTC)[reply]

One thing I can think of right off comes down to safety, namely the ability - or lack thereof - of the individual to wear protective equipment such as hardhats or fire helmets. RegistryKey(RegEdit) 05:27, 20 January 2015 (UTC)[reply]
Won't it put pressure on the growing brain, if the skull is prevented from spreading apart to accommodate the growth ? StuRat (talk) 05:28, 20 January 2015 (UTC)[reply]
Despite my skepticism, this source seems to agree with that, at least to some extent. (bear in mind that we CANNOT guess from our armchairs whether this surgery is necessary or not, and I certainly haven't read enough to dream of doing so) Wnt (talk) 22:36, 20 January 2015 (UTC)[reply]
Understood; I'm basically asking a variant on the beta strep infection question at Kainaw's criterion. Nyttend (talk) 23:02, 20 January 2015 (UTC)[reply]
Nyttend, I understand the distinction you are trying to make there in referencing that essay, but I am concerned that we are already abutting the border between the two scenarios it attempts to separate. Nontheless, I'm going to point you in the direction of these resources... [1], [2], [3], [4], [5], [6], [7], [8], [9], [10] ...but without summarizing their findings. Snow talk 08:56, 22 January 2015 (UTC)[reply]

Scratching athlete's foot - better than sex?

[edit]

Can scratching athlete's foot be more enjoyable than sex?

If so, how does that work?

(Please provide references, if you can). The Transhumanist 10:50, 20 January 2015 (UTC)[reply]

I Googled "'athlete's foot' 'more enjoyable' sex" and found Seven Reasons to Get Out More at the top. Might be worth a ponder. InedibleHulk (talk) 11:09, 20 January 2015 (UTC)[reply]
  • There's no objective way to measure this, so only experience will tell, and we can't advise you to have sex, nor to contract a variety of athlete's foot and itch it. Contact your physician/clinical psychologist/dermatologist/sex surrogate. μηδείς (talk) 20:57, 20 January 2015 (UTC)[reply]
  • Enjoyment (whether from sex, chocolate, a good belly rub, "runner's high", or any number of other sources) is largely a function of neurochemistry, mostly by compounds called endorphins. An individual's response to any activity is unique, so it's entirely possible for one person to have a greater "endorphin rush" from any specific activity than from sex. The world has 7ish billion people. I'd not be shocked if you told me any one of them enjoyed any random activity more than sex. --Jayron32 02:19, 21 January 2015 (UTC)[reply]

User:InedibleHulk, User:StuRat, User:Baseball Bugs, and the rest...

I've been working on the article athlete's foot. While reading up on and search-browsing the subject, I came across many posts in forums by persons claiming to have reached levels of orgasmic bliss by scratching or rubbing their athlete's foot. Some scratched or rubbed themselves into a state of ecstasy until their feet were raw or even bleeding. Some even went so far as coddling the disease instead of eradicating it, so they could relive the experience once their feet healed up from the previous scratch session. So I'm wondering if there is any scientific literature on this phenomenon that answer the following questions: What is it called? How prevalent is it in the population? What exactly is going on (physiologically)? And what is the role of athlete's foot fungus in this? The Transhumanist 07:32, 21 January 2015 (UTC)[reply]

As to what is going on physiologically, this study regards itching in general and how it effects the brain. It states in the abstract "Our findings not only confirm a role for the central networks processing reward in the pleasurable aspects of scratching, but also suggest they play a role in mediating itch relief." And this study finds that the most pleasure is gotten from scratching the ankle. Newspapers took that last study to mean that scratching the ankle is better than masturbating. I can't find any name for the practice, I would just call it a scratching fetish. In both studies something was done to make the skin itchy as oppose to having people scratch for no reason. I think your guys trying to get athlete's foot just haven't figured out more effective ways to induce itching. I do not think it should be part of the athlete's foot article, but part of the Itch article if at all. Richard-of-Earth (talk) 10:57, 21 January 2015 (UTC)[reply]
Algolagnia is a love of pain (as distinct from masochism), and urtication is the practice of applying irritants in a sexual context - scratching fetishes probably come somewhere between the two. Tevildo (talk) 18:24, 21 January 2015 (UTC)[reply]
It doesn't fit within the definition of sexual fetish, because there is no sexual arrousal, just extreme pleasure from scratching, so good it can be compared to the levels of pleasure received from sex. Any references about how the fungus causes itching, the scratching-pleasure feedback loop, and anything about how this might be a survival adaptation of the fungus, would be most helpful. What I'm lacking here are search terms, I have no idea what these phenomena are called or how they might be described. I would be very impressed if you could find any scientific literature, even if it only includes observations, about this in relation to fungi responsible for athlete's foot. The Transhumanist 18:53, 21 January 2015 (UTC)[reply]
My initial impression from the question was the "ick" factor - particularly if you don't thoroughly wash your hands afterward. You don't want to end up with "Athlete's Eyeball", for example. ←Baseball Bugs What's up, Doc? carrots14:09, 21 January 2015 (UTC)[reply]

I'm punching in every relevant search phrase I can think of into Google. Any suggestions? The Transhumanist 18:53, 21 January 2015 (UTC)[reply]

Why is NASA hoarding the Dawn data on the Ceres mission?

[edit]

I was very disappointed not to find a raw image feed for Dawn as it approaches Ceres [11], and apparently this is deliberate. [12] Are these images ever being released, or are they being hoarded as a commercial asset, or is NASA afraid that big bright spot really is an alien monolith? In this day and age how can they justify hiding away the data? Wnt (talk) 14:02, 20 January 2015 (UTC)[reply]

I think this is just a variant of an Embargo_(academic_publishing) (we don't have a page specific for data embargo but I think you get the point) - the idea is that the NASA researchers should have first claim to publish findings based on the data. We wouldn't want NASA scientists being "scooped" by somebody else! After some time has passed, much of it will probably be made available to the public. Here's a blurb about embargoes at the ESA from the Rosetta mission, which also says
Of course the frustrating thing is that they can embargo some things, let others out immediately, never release some stuff. To my knowledge it's all highly discretionary, either by the PI or some higher level of NASA management. NASA does have a data portal [14], but while it has a lot of stuff, it is sparse compared to what NASA has collected. Btw, to my understanding this wouldn't be an issue for research funded by the NIH - who now requires all research that they fund be publicly released [15] - though of course that's still after publication, not raw data that has not yet been analyzed. So maybe write to your congresspeople and say you want access to NASA data since you paid for it (assuming you are taxpaying a citizen of USA)? SemanticMantis (talk) 15:00, 20 January 2015 (UTC)[reply]
Looks to me, as if this is a NASA Public relationsinitiative thats gone wrong. Let me play the devils advocate here,(warning – my personal opinion follows): A NASA Bean-Counter thinking to himself: These probes cost the tax payer billions. I have to justify this expenditure so we can send more and I can keep my overpaid job. Hum thinks... When things are free, they are viewed to have little value. So! Let's withhold these images from Dawn and so create scarcity – thereby increasing the public's hunger. Which of course doesn’t increase their scientific value but slows the process of discovery down. Therefore, I don't think its for economic gain but rather a misguided sense of power-politics from within NASA. We pay for the development of these robots and the means to deliver them to their destinations and the teams of scientists and technicians required to operate them, etcetera, so why should we not decide, what we receive and when? NASA had better think again -if it wants our hard earned tax dollars in the future.--Aspro (talk) 15:15, 20 January 2015 (UTC)[reply]
Whilst I've been typing, Samantha (my cat) has been walking and pawing all over her keyboard and found we are not alone:A plea for more pictures from Dawn--Aspro (talk) 15:22, 20 January 2015 (UTC)[reply]
(EC) There is some informed discussion starting from about here [16]. At least as of that time (in 2011), it doesn't sound like anyone actually asked why the policy was in place, but it seems it's not unique in NASA projects. The specific phrase (actually a lot of the Daily Mail article), originated from this 2011 AP source [17]. It sounds like a lot of data will be eventually released to PDS [18] (and GB from earlier parts of the program has been [19]), probably within 6 months or so of some time, it's mostly that the raw images aren't be released when received unlike with some other projects. There is some brief newer discussion here [20] but there wasn't any mention of any reason ever being established beyond the fact that they were considered largely uninteresting etc. Nil Einne (talk) 15:44, 20 January 2015 (UTC)[reply]
After EC, the above link from Aspro helps clarify a bit of what I read in my sources above. The bit about being uninteresting etc was largely relating to the stuff on approach to Vesta (and Ceres etc I guess). Not much of this was really made available as it happened and there was some attempt to get explaination and suggest a change of policy about this part. Once it reached Vesta (or Ceres etc) the more interesting images were released using the one a day policy. At least in the stuff in the unmannedspaceflight forums, there's no info I can find on anyone actually asking why they had the one a day policy, while the principle is somewhat similar to the limited release for the approach images, the specific reasoning won't I guess work (except perhaps they may say a lot of the images aren't that interesting particularly without touchup so they prefer to select the best or something).

Ultimately the view appears to be this likely is much more to do with the PI than to do with a bean counter or any hope for commercial asset anyway (and I'm not sure how the later is supposed to work anyway, it's not clear there's sufficient researchers interested and willing to pay enough to make it worthwhile, and for the media there's little NASA can do since any of the stuff from NASA is in the public domain so while they could give some media who pay exclusive access, everyone else is freee to copy once this media actually uses it.

Nil Einne (talk) 16:07, 20 January 2015 (UTC)[reply]

How many months might it take to Photoshop out any cities which showed up on photos of outer planets? Edison (talk) 17:26, 20 January 2015 (UTC)[reply]
They discovered that the bright spot was actually a planet destroyer weapon left over from the apocalyptic war of Phaeton. And NASA scientists are now furiously debating the ethics of revealing this to the public. Elsewhere, the intrepid little explorer Curiosity stared at the Martian sky and whispered "That's no dwarf planet!" in his faint beeping language unintelligible to humans. -- OBSIDIANSOUL 03:36, 21 January 2015 (UTC)[reply]
Wnt: If you are an amateur observer, you can join the Amateur Observers' Program to get access to Dawn data. If you are a professional researcher, you can contact NASA or the Dawn Science Team for more specific requests. It goes without saying that if you don't know what data you are looking for, you aren't going to get very far by asking for it. Spacecraft are immensely complicated; raw scientific data isn't always available in a format that you will know what to do with; it would be silly for the uninitiated outsider to send a mail asking for "the latest photographs from the spaceship." From which instrument do you seek data? In what capacity do you wish to analyze the data? ... and so forth. It has been my experience that whenever I ask for data - provided that I do enough homework and ask the right questions - NASA grants me access to said data - even if it is not available on their public website. It helps if your mailing address is a professional research institute or a reputable research university. Nimur (talk) 21:49, 20 January 2015 (UTC)[reply]
That sounds very paternalistic if you don't mind me saying so. This is 2015. Even laptops to-day have computing power that in my youth would have filled up an air-conditioned room – or two. In my day, we did not have the internet to help us find what Reed–Solomon code even was. To-day, a keen amateur only needs access to the raw data. If this data was available – there would be no need to email anybody and ask the right questions -would there? Which is all tax payers are asking for – or is that too much to ask for? This smells like a bean-counter and PR job gone wrong, and without our support they don't have jobs.--Aspro (talk) 23:04, 21 January 2015 (UTC)[reply]
Sir, while you are entitled to your opinion, the difference between your approach and my approach is that I actually get to look at interesting astronomical images. Nimur (talk) 05:52, 22 January 2015 (UTC)[reply]
That’s the problem. Without the red tape, ordinary tax payers would have the same access as you, yourself. --Aspro (talk) 21:48, 22 January 2015 (UTC)[reply]
That's good to hear. Still, much of the point of looking at something like the Cassini raw data is to get the sense of what is available. How much is processing, and how much is actually the instruments? (In that case, mostly the instruments! Though the color channels were a bit unusual, they were still not much different from the usual image you get from a regular digital camera) I admit, I didn't have a noble or professional purpose in mind here, more to play around with some scripts and maybe see if I can make a case that the images of the bright spot are resolving into a sphinx, dragon, statue of Ozymandia... :) At best a one-day blog wonder, with mirth to be had by all, except in the unlikely but not utterly impossible case that it turns out to be so. :) Wnt (talk) 23:33, 20 January 2015 (UTC)[reply]
For Cassini/Huygens, begin by reading NSSDC's Cassini Data Archive manual. That book tells you where to get the data - what servers to connect to, which people to contact, and so on. Understand that Cassini was a multi-billion-dollar mission. The volume of data produced is massive. It might take a few world-class supercomputers to handle "all" of the "raw data."
You are probably more interested in what space scientists call "high level science product" - the sort of refined image data that can actually be used to construct a photograph of an interesting astronomical target. ...But you can grab any dataset you like, if you know how to use that data product. First, decide the instrument and data product you want to work on. Then, peruse the public repository at NSSDC's Cassini data collection. Anything that the spacecraft produced that isn't in the public web-database can be located by contacting the appropriate PI as documented in the catalog manual.
If you wish the same for Dawn Mission, here is NSSDC's Dawn data collection page.
I'm really not trying to be snarky - but just because the data is freely available doesn't mean it is useful to you. There is a reason that some people spend ten or so years studying physics and astronautical engineering - specialization of labor. If a very smart team of people spend ten years designing a mission instrument, it is not plausible that an amateur hobbyist - irrespective of his/her intelligence and skillset - can casually interpret the scientific instrument's data.
Does it take a long time for NASA to post data? Sure. Dawn's X-band downlink can be as slow as 10 bits per second. How long does it take to link a 24 megabyte QUB file? You do the math. When it's done, you've got ... a QUB file that's only meaningful to a handful of scientists at Max Planck institute. And remember that science data link must always be prioritized behind flight operations communication.
Nimur (talk) 05:52, 22 January 2015 (UTC)[reply]
“but just because the data is freely available doesn't mean it is useful to you.” ?!”it is not plausible that an amateur hobbyist”?! Marie Curie wasn't a qualified nuclear physicists. Radar was developed from observations of amateurs too. Edward Jenner wasn't a qualified virologist. The list goes on and on. One of the reasons that mankind has been so successful is that people do specialize... and cross pollinate with other disciplines. This is why data should be easily accessible. Some of those people who need easy access to this info (who you say don't know how to make use of the data) may be in a specialization (experts in their own right) that can bring new insights, that the privileged academics (like you) that can sail through the red tape may not. So by not seeing this, you have inadvertently proved the point that you are not the best decider of how this tax-payer-paid-for info, our info is best distributed. As I said before: That sounds very paternalistic if you don't mind me saying so and even more so now.--Aspro (talk) 21:12, 22 January 2015 (UTC)[reply]
I'm not very clear about how you get from "connections as slow as 10 bits a second" to needing "world-class supercomputers", but thanks for the information. This does get me through to a directory whose readme says "This EDR dataset is the primary record of image data as it was received on Earth. The images in this dataset have not been processed in any way other than by decompressing, extracting header information, and generating and attaching PDS labels. Which means that the answer to one of my questions is that yes, raw data is indeed available from Dawn, within a very reasonable definition. Now I'll admit, this .IMG file is still a little 2313374ME, but people say we ought to be able to decipher images sent by alien civilizations, so with a little digging there's probably a way. A bigger problem though is I don't see anything in the folder more recent than 2013, nor a "Ceres" collection on the list. But we're getting there. In the dark you can't learn about a wall except by running into it. :) Wnt (talk) 15:34, 22 January 2015 (UTC)[reply]
Again - let me reiterate - jumping into the database before you spend a solid month learning the data products catalog - might be going about things backwards. There is documentation for all the esoteric file formats and unusual instrumentation output - but it's written by researchers - so you just might need a Ph.D. to understand it. Nimur (talk) 16:16, 22 January 2015 (UTC)[reply]
esoteric file formats?!! Oh. So you are saying that this data is only for the selected few (which you seem to count yourself amongst). Whilst your fellow tax payers should just cough up their hard earned dollars, so you and other lackeys alone have privileged access. What absolute I'am holier-than-thou twaddle. As your Mom might have forced upon you - or in your case probably not: Wash your mouth-out with soap and think before you type.--Aspro (talk) 00:46, 23 January 2015 (UTC)[reply]
  • I'm just glad I will probably live long enough to see the planets Ceres and Pluto. Back when the first Voyager images of the gas giants came back we were all still thinking about fallout shelters. Once I've seen them, being consumed by grey goo in 2017 will not seem so bad. μηδείς (talk) 01:57, 21 January 2015 (UTC)[reply]

@Wnt:, You need to read Kim Stanley Robinson's most elegant Icehenge before May 1st. μηδείς (talk) 02:00, 21 January 2015 (UTC)[reply]

Goddard's first rocket

[edit]

See File:Goddard and Rocket.jpg. What's what? I see two sections, connected by little lines: a little thing at the top, and a big piece almost as tall as Goddard at the bottom; is one the rocket, and the other an associated device, or are they two parts of the same thing? And is everything else the frame, which sat still when the rocket was launched, or is he holding onto part of the rocket? It would help if someone could add annotations (see Commons:Help:Gadget-ImageAnnotator) to the image, explaining what's what. Nyttend (talk) 18:21, 20 January 2015 (UTC)[reply]

There is a labeled diagram here: [21]. Seems like something we could re-create as an SVG and place side-by-side with the actual photo in our article, rather than having to click through to and hover to see annotations. DMacks (talk) 18:34, 20 January 2015 (UTC)[reply]
So based on that, the short answer is that he put the rocket motor above the fuel and oxygen tanks. Presumably he wanted the thrust applied at a point above the center of gravity so that the assembly would be stable without needing a steering mechanism. And the obvious downside is that the exhaust impinges on the tanks, so it wouldn't work for rockets meant to fire for more than a short time. --65.94.50.4 (talk) 18:52, 20 January 2015 (UTC)[reply]
Actually it don't matter if the rocket is firing for a long or short time, since the 'obvious' idea of trying to stabilise a rocket by using the weight of the tanks as a pendulum simply don't work. See Pendulum rocket fallacy for a practical and physical explanation of why - it's a short and concise read =) WegianWarrior (talk) 18:58, 20 January 2015 (UTC)[reply]
  • Thanks! I wasn't imagining the behavior of a pendulum when I wrote the above, but rather an object like a cart being pulled rather than pushed along the ground -- but the fallacy of generalizing this to the rocket is the same as with the pendulum. --65.94.50.4 (talk) 05:48, 21 January 2015 (UTC)[reply]
My question grew out of the section up above where this fallacy is mentioned. Until reading that he put the tank below the engine, I had never noticed the thing on the ground (the actual tank); I'd only ever noticed the rocket up at the top of the picture. Nyttend (talk) 22:58, 20 January 2015 (UTC)[reply]
The tanks were above the engine. The rocket engine is only at the top in the photograph for fueling. It launched the other way up. Otherwise, is would have embedded itself in the ground! --Aspro (talk) 21:46, 21 January 2015 (UTC)[reply]
So you think it launched with the nozzle pointing upwards? In that case it would have embedded itself in the ground! --65.94.50.4 (talk) 01:58, 22 January 2015 (UTC)[reply]
I think it's in launch position now, and that the engine on top will fire downward, onto the engine. This wound't be very efficient, but was sufficient to test the stability theory. I wonder if instead of a rigid frame, if he ever tried the fuel tank suspended by a hose. It would have to be able to withstand the rocket blast, of course. Perhaps 3 rockets spread out with the cable in the center would protect it better. I'm not sure how this would affect stability, but it would make for an interesting test. StuRat (talk) 18:42, 22 January 2015 (UTC)[reply]
This Goddard rocket nonsense has been circulating longer that the Moon landing conspiracy theories. Found this old ref that explains more: New Scientist 18 Dec 1986 Hope this helps.--Aspro (talk) 19:44, 22 January 2015 (UTC)[reply]
It certainly does: "Goddard's first rocket is unusual, because the combustion chamber is at the top of the rocket stack with the liquid oxygen and petrol fuel tanks below. Ball thinks that the rocket probably flew only once in this configuration..." When the article says it was reversed 180 degrees and could not have been fired, it has to be talking about which side of the rocket is facing which side of the launch stand. --65.94.50.4 (talk) 04:01, 23 January 2015 (UTC)[reply]