Wikipedia:Reference desk/Archives/Science/2017 November 4

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November 4

Star in Cancer named for Marina Popovich

Marina Popovich says that a star in Cancer is named after her, but the reference is in Russian and it doesn't come up for me. Which star is it? (List of stars in Cancer doesn't list those types of names.) Bubba73 ^{You talkin' to me?} 05:24, 4 November 2017 (UTC)

Very few stars are officially named after individuals. See IAU Working Group on Star Names, and note that the lists linked from that article's references do not include the names "marina" or "popovich". So this seems unlikely. (Note, there are companies that sell the right to "name" a star but nobody else recognizes those names. See Stellar designation#Sale of star names by non-scientific entities.) --69.159.60.147 (talk) 09:18, 4 November 2017 (UTC)

Cancer is her Sun sign (90 to 120 degrees ecliptic longitude). Sun in International Astronomical Union Cancer after 8:41pm UTC+3. Sagittarian Milky Way (talk) 12:57, 4 November 2017 (UTC)

That reference is dead. Ruslik_Zero 20:39, 4 November 2017 (UTC)

This here says it's Alpha Cancri (last para), and it was Gherman Titov who gifted her the certificate to the effect. However, as has been noted, unlike comets, say, stars are never officially named after people, not that it keeps shady companies from selling the stuff. 78.53.24.148 (talk) 21:21, 4 November 2017 (UTC)

• That's what I was going to say, but then I looked at the references (cited above). Very few stars are officially named after individuals, but "never" is now wrong. The longstanding nickname Barnard's Star is now an official name, for example. --69.159.60.147 (talk) 04:24, 5 November 2017 (UTC)

Thanks, I thought that it probably wansn't official. Bubba73 ^{You talkin' to me?} 02:42, 5 November 2017 (UTC)

Resolved

(Simply because it hasn't been linked yet) Stars named after people does list a few more besides Barnard's Star. Some, such as 61 Cygni aka 'Bessel's Star', do have different official names, but there are other examples (e.g. Kapteyn's Star). Marina Popovich is not on that list, nor is she mentioned in the subsection "Covertly named stars". ---Sluzzelin talk 05:28, 5 November 2017 (UTC)

Most comets are named after people, and so are some asteroids 45 Eugenia. 86.155.148.59 (talk) 16:00, 5 November 2017 (UTC)

Stars with naked eye

I couldn't figure out how to word it properly with Google but my question is: I see a lot of amazing pictures of galaxies and stars and cosmic dust and all that, but how much of that is actually visible to the naked eye? I am planning to take a trip to a place with little to no light pollution and I'm trying to temper my expectations. Thank you! — Preceding unsigned comment added by 80.6.102.227 (talk) 22:21, 4 November 2017 (UTC)

See Bortle scale for examples of astronomical objects visible with the naked eye at various levels of light pollution. The Naked eye article may also be useful. Tevildo (talk) 22:28, 4 November 2017 (UTC)

As Bortle himself explains here, you need to get quite far away from big cities, light reflects back from the atmosphere, making the sky even 100 km away from a city become very slightly gray. While you can then see many faint stars, nebulae with low surface brightness will still be drowned out. E.g. in Western Europe, you won't be able to easily see the Triangulum Galaxy with the naked eye, it may be possible to see with a lot of effort from the Alps. This is because it's hardly possible to get away more than a few hundred km from a large city like London, Paris, Brussels, Berlin etc. etc. in Western Europe. Ideally you need to be 1000 km away from such big cities, then you should be able to easily spot such faint objects like the Triangulum Galaxy. It is from such places where you can spot even fainter object with effort, e.g. the astronomer Brian A. Skiff has seen the galaxy M 81 with the naked eye as he mentions here. But he failed to spot Neptune with the naked eye, even though it is theoretically possible to do so. Count Iblis (talk) 00:34, 5 November 2017 (UTC)

The less lightpollution the better ofcourse but actually the weather is much more important since without a clear sky, without any lightpollution, you would only have a "lightunpolluted" view on the clouds. --Kharon (talk) 01:59, 5 November 2017 (UTC)

You don't need 1,000 kilometers. Maybe in space or in an airplane when you can see further but from sea level look at the light pollution map of the ocean near New York or Tokyo. If you need 1,000 kilometers somewhere it's because of closer cities, suburbs or farms, not because of your city (also light fishing and human and natural fires can cause enough light to cause light pollution. I haven't done the math to see if there's enough air in the volume lit enough by a candle for things that small to cause it too but if it could it'd only have inches or feet of range. You'd also have to avoid seeing the candle or anything lit brightly by it for 30 minutes to adapt your eyes to the dark before you could test this. [You can look at a candle from less than 1,000 feet away without affecting your dark adaption] so it's got to be much closer if the air around that light is glowing enough from scattering to affect the view) Sagittarian Milky Way (talk) 05:52, 5 November 2017 (UTC)

Photographs of the less bright astronomical objects usually show too little (especially film without a bulb setting) or too much (i.e. taken in space, infrared, composites of long exposures, sometimes including black and white frames through a filter that blocks all but the tiny fraction of the rainbow nebulae glow in (which are then colored i.e. hydrogen red in software, nebulae can be seen with the naked eye but they're gray and usually smaller)) Infrared's pretty neat. The naked eye Milky Way looks brighter the closer to the center it is (both centerline and center point) except a rift of dust seems to block what would be some bright-ass stuff. And it is, Milky Way dust is amazing. 1,000 light years doesn't dim much but 50,000 light years towards the far side of the galaxy dims 100,000,000,000,000,000,000 times. The redder the light or infrared the picture is taken in the further into this dust you can see. Also most stars are brighter in infrared than any color of light. There's a star barely visible to the naked eye that's the 3rd brightest star in the sky in near-infrared. It's a class above Sirius in any color of light but it's just too red for humans. Sagittarian Milky Way (talk) 05:34, 5 November 2017 (UTC)

the Andromeda Galaxy, left

The user geolocates to Dunstable, UK. In New Jersey one can go to the New Jersey Pine Barrens, Batsto, New Jersey being a good place to stop right off the road in a public field, and see the Milky Way and a very bright starry sky on clear, moonless nights. But in the Northern Hemisphere galaxies appear at best as star-sized nebulae to the naked eye. The Andromeda Galaxy, the closest non-dwarf galaxy to ours is in the Southern Hemisphere. μηδείς (talk) 02:30, 5 November 2017 (UTC)

That location isn't too similar to what the darkest possible looks like really. It's only dark by New Jersey and Philly area standards. The closest land you can't detect light pollution with the naked eye from if you know what to look for might be Canada. Sagittarian Milky Way (talk) 04:08, 5 November 2017 (UTC)

View north from a fire tower on Apple Pie Hill in Wharton State Forest, the highest point in the New Jersey Pine Barrens

Your one-upmanship is not particularly helpful, SMW. The Pine Barrons cover 1.1 million acres (4,500 km2; 1,700 sq mi), some 22% of New Jersey's land area, and comparing the land pictured to Philadelphia is simply ridiculous. I might as well say that the heights of the Andes or the Himalayas are better than Saskatchewan for star-watching, and then of course there's Earth orbit or the dark-side of the moon. I simply noted an easily-accessible area between Philadelphia and NYC where one can indeed see things like the Milky Way and the Orion Nebula. μηδείς (talk) 23:53, 5 November 2017 (UTC)

Above 3 kilometers only helps if you stargaze with oxygen bottles cause dark adaptation's one of the first things to go. I guess astrophotography would still work till the height you forgot how to use a camera. Sagittarian Milky Way (talk) 09:39, 7 November 2017 (UTC)

File:Northeasthsalpmap.jpg

This is why I mentioned they're only dark by Jersey and Philly metro (5000 mi²) standards. The Pinelands are a great resource for everyone in the marked area but if someone's coming all the way from England they should know that they're not that dark by North American or even 2 hour drive from New York City standards. For radii between c. 60 and 150 miles the circle actually contains darker land when centered on NYC than Philly.

Ah, do you want to check that? I think you might have your chart upside down. The Andromeda Galaxy – with a declination of +41° is very much visible in the northern hemisphere, and most easily viewed from there. For southern observers, Andromeda never gets very far from the northern horizon. The Magellanic Clouds are presumably the dwarf galaxies you're thinking of, and they're both around -70° declination, deep in the southern sky. TenOfAllTrades(talk) 03:16, 5 November 2017 (UTC)

You're right, I was thinking Magellanic Clouds. Stupid me. In any case, you still need visual aids to make out anything other than a fuzzy star. Where I live, you are lucky to see Orion, Sirius and the Pleiades in the right season, and perhaps the Big Dipper. μηδείς (talk) 03:39, 5 November 2017 (UTC)

The Large Magellanic Cloud isn't small to the naked eye. And the Milky Way doesn't look too dissimilar to astrophotographs of spiral galaxies edge-on and is a bit more than a fuzzy star (360 degrees wide). Sagittarian Milky Way (talk) 04:08, 5 November 2017 (UTC)

You are contradicting a claim I didn't make. The fact that it's called a cloud kind of gives it away, doesn't it? μηδείς (talk) 23:10, 5 November 2017 (UTC)

Ah yes you're right, the visual aids is still about the Northern Hemisphere (I'll ignore the tropical northern since the view is so degraded that far from 70°S it's close enough). Nebula means cloud (coined decades after the telescope) so it's not blatantly obvious to me that a cloud has to be big. Sagittarian Milky Way (talk) 02:12, 7 November 2017 (UTC)

So now you are reverting to reverse time travel [redacted by Medeis]? The objects were called Las Nubes de Magallanes when reported by Magellan's expedition. (Nube literally means cloud in English, and is not technical term referring to the small fuzzy objects which vexed Charles Messier who catalogued them to distinguish them from the comets which he was interested in or William Herschel who determined that the Messier Objects were comprised of stars.)

This predates the astronomical use of the term nebula with the astronomical meaning "cloud-like patch in the night sky" first recorded c. 1730. The suffix -ulus/ula is a diminutive derived from Latin, so of course nebulae are small, and "nebula" is not the equivalent of "nube", but of Spanish nebulosa. μηδείς (talk) 03:51, 7 November 2017 (UTC)

Okay you're right, little cloud. Looks bigger in a 'scope but I'm centuries too late to suggest nube. Sagittarian Milky Way (talk) 09:09, 7 November 2017 (UTC)

I did some searching on this question a while ago while writing a trivia-league question. Pretty much every source I checked made different assumptions and gave different numbers, but the consensus was clearly that under ideal naked-eye conditions on the Earth the number of stars you can see as individual objects at one time is a few thousand. The question is whether you can see stars of magnitude 6 or brighter, or 6.5 or brighter, or whatever; also, stars near the horizon are dimmed and you won't be able to see all of them that you could if they were higher. Anyway, I downloaded the Bright Star Catalog, which was available somewhere under here, and found 5,080 stars listed of magnitude 6 or brighter; 8,404 of magnitude 6.5 or brighter. Of course at any particular time and place about half of them will be below the horizon. So it's pretty safe to assume 2,000-plus; 3,000-plus, maybe not. --69.159.60.147 (talk) 04:36, 5 November 2017 (UTC)

The sky with the most individually distinguishable naked eye stars probably has the Milky Way near the zenith. The winter sky has more bright stars cause of the Orion Arm which we're in (but closer to the inner edge), the summer sky has more dim stars cause the Orion Arm's a minor spur of the Persus or something arm and the next arm in (Scorpius-Sagittarius?) is major but further (as one would expect from us being in a minor inner spur of the next outer major arm). The Southern Hemisphere's uhm, Northern Hemisphere spring (their autumn) sky probably has more individually resolved stars than the Northern Hemisphere's fall and you could still see some of the midnorthern latitudes' summer and winter stars when Centaurus or Crux is overhead so it's probably not when the Cepheus or Cassiopeia Milky Way is high. Sagittarian Milky Way (talk) 05:32, 5 November 2017 (UTC)

See Dark-sky preserve. There is an organisation which inspects areas and grades them [1]. 86.155.148.59 (talk) 15:22, 5 November 2017 (UTC)

As an aside, here's a link to a worldwide light pollution survey, presented as an overlay on Google Maps: link. (Sadly, I live in one of those big-city white areas at the ugly end of the Bortle scale.) The map is based on 2006 data, but most areas won't have changed much beyond a gradual worsening. TenOfAllTrades(talk) 15:26, 5 November 2017 (UTC)

I do wonder if we're taking the question in a bit of the wrong way. Counting stars and spotting Triangulum are certainly ways to assess viewing conditions, but I get the impression that the OP is perhaps at least as interested in a more qualitative description, with particular emphasis on similarities and differences between what you see with the naked aye versus photographs. Correct me if I'm mistaken, but I presume that the OP is new to dark-sky observing (and probably has fairly limited observing experience in general—welcome to the hobby!); learning to find the most obscure and difficult-to-see objects probably isn't the priority here. So what are the differences that will stand out?

• A lot more stars. With the naked dark-adapted eye, good seeing (that is, good atmospheric conditions), clear skies, unobstructed view to the horizons, and (this is important) no Moon, you're looking at somewhere over 4000 stars at magnitude 6.5 or brighter: [2]. This compares quite favorably with the few dozen you might see from a city location, or the few hundred you might get at a suburban site.
• But not all the stars. Telescopes, binoculars, even regular camera lenses all capture light through a front aperture bigger than the pupil of your eye, and so they collect a lot more light to play with. (This page shows the difference between a 200 mm medium-sized amateur telescope and the human eye in the first figure.) Film or digital camera sensors can collect that light over an extended period of time, too (several seconds, minutes, or even hours), to pull even the faintest objects out of the background. I know from experience that if I put my very average consumer-grade DSLR on a tripod outside with a good-but-not-stellar (ahem) medium-angle lens, I can shoot a five-second exposure that easily displays stars that are fainter than 9th magnitude—even from a badly-light-polluted city location.
• Less color than you might expect. Color vision just isn't very sensitive. Most stars, even under ideal conditions, look plain white; a few of the brightest ones have visible color: [3]. Similarly, the small number of naked-eye nebula (like the Orion Nebula) are smudges of gray, not sprays of violet: [4].
• Lower magnification and resolution. Globular clusters are smudges rather than dense piles of pinpoint stars. Most of the objects in the sky won't show structure or detail to the naked eye, just smudges and single points. Remember that the list of Messier objects was compiled by a frustrated naked-eye comet-hunting astronomer who wanted a catalog of all the little fuzzy smudgy things in the night sky that looked like they might be comets—but weren't. (Amateur astronomers refer to faint nebulae and distant galaxies – somewhat tongue in cheek – as 'faint fuzzies'.) For a few extended objects, you may only be able to see the brightest parts with the naked eye. For example, the Andromeda Galaxy is nearly three degrees wide (the full Moon is only about half a degree across) but you'll only be able to see a wee smudge in the middle with the naked eye.

All that said, don't get the impression that it's not worth looking at the night sky with the naked eye. It's magical. The sky feels close enough to touch. The Milky Way is awesome. Be patient and let your eyes get fully dark adapted. Do not look at your smartphone. Lie down on your back and soak it in. TenOfAllTrades(talk) 15:26, 5 November 2017 (UTC)

Actually those smartphones seem like they ought to be useful. Invent a way to put their display in a really dim adjustable "starlight mode" that is maybe 10-100 times brighter than the stars at arm's length. Use their various position-orientation spy stuff to get them to calibrate their position based on a camera photo of the moon, or else by user sighting at stars. Then have them present a light-amplified view of whatever is directly behind them. (Not by using the camera, which I *assume* is not yet spy-grade enough to see the stars, but based on orientation; the user would still need to align his head right) Wnt (talk) 13:49, 6 November 2017 (UTC)

This is a well established genre of phone app. I use an Android app called Star Map [5] that does exactly that, although it doesn't need to be calibrated since the phone has GPS. The link above also shows a number of other apps that seem to operate similarly: Star Walk, Sky View, Star Chart, Star Tracker, Night Sky, SkEye, etc. CodeTalker (talk) 15:27, 6 November 2017 (UTC)

Using food or money on research participants

When “animals” are used in research experiments, they are rewarded food. When humans are compensated for their time, they are given money. Is this just a widespread assumption by the researcher, or are humans really attracted to money over food? If a researcher has a low budget, then will offering a piece of fruit work instead of giving money? Or do researchers still have to allot some of the budget to paying the participants? 50.4.236.254 (talk) 23:55, 4 November 2017 (UTC)

The articles Human subject research and Animal testing give some perspective on these kinds of research, both of which are normally guided by ethical restraints, see ref. 1 and ref.2 respectively. Financial or food incentives may form part of the research methodology, or merely be necessary outlays to obtain participants. Blooteuth (talk) 01:20, 5 November 2017 (UTC)

(ec) There are some questionable assumptions there about how humans are compensated for their participation in research. Over the last few decades, I have received:

• A smidgen of course credit (in an undergraduate introductory psychology course) for participation as a subject in psych experiments;
• A chocolate chip muffin in exchange for a vial of blood (while a grad student) for a neighboring bio lab that needed a 'normal' control;
• Nothing whatsoever in exchange for consent to carry out research using biopsy specimens collected in the normal course of a surgical procedure I underwent;
• A small-but-not-negligible cash payment (enough for dinner and a pint at the local pub) for participating in a series of telephone surveys tracking my recovery from the surgery mentioned in the previous bullet.

In my very tiny sample of experience, research participation has seldom resulted in a cash payment, and food has been used as a perfectly acceptable reward.

More generally, there are serious ethical concerns around cash payments to research subjects. Research ethics boards (REBs) and regulatory agencies (like the FDA) tend to frown on studies that propose using overly-large payments to influence subjects and induce consent or agreement to participate in studies against their better judgement. These guidelines from UC Berkeley touch on a number of principles, and highlight the potential for undue influence or coercion. These guidelines from the University of Toronto draw a distinction between reimbursement (repayment for out-of-pocket expenses like transportation and parking) and compensation (payment – monetary or otherwise – for the participant's time and effort).

On the question of whether and how various rewards work, here's a quote from a relevant paper.

"However, empirical evidence demonstrating that payment is necessary and/or effective for the recruitment of clinical research subjects is limited. People appear to be attracted to research and motivated to participate for a variety of reasons. Healthy volunteers, who are frequently paid and unlikely to benefit medically from research participation, are often attracted to research and motivated to participate by money. Yet they appear to have a variety of other motives besides those of a financial nature for participation in research, including curiosity, altruism, sensation seeking, and desire for attention provided by physicians (24–26). Patient-subjects — those who suffer the disease or condition under study in a particular research protocol — are often motivated to participate by the hope of personal therapeutic benefit. When patient-subjects enroll in clinical studies and they understand the likelihood of direct medical benefit to be remote or nonexistent, their motivations are likely to be similar to those of healthy volunteers. Although patient-subjects are often offered payment for their participation in clinical studies, little research has been done to evaluate the extent to which money influences recruitment or their willingness to participate (21). Given the diverse motivations of subjects in clinical research and a lack of relevant data, it is difficult to know how much paying subjects helps to accomplish recruitment goals."

The short version is that different people are motivated by different things, and study participants often receive trivial compensation. TenOfAllTrades(talk) 01:39, 5 November 2017 (UTC)

The question is confusing "reward" as part of a research protocol itself (training a behavior, etc.) with "compensation" for being a participant. You don't need to pay mice, you just pay a breeder and then drop them in your maze. Token rewards involved in protocols depend on what behavior is intended to be learned. DMacks (talk) 01:49, 5 November 2017 (UTC)

From what I gather by talking with my fellow clinical trial participants, while some do it out of charity, they still need to take unpaid leave to participate, still other participated to raise funds while on an OE. I was one of the former, and I would be rather irked if I weren't comensated for my lost earnings. I already sacrificed my time, and it's exhausting being poked and prodded at all hours of the day and night. Offering me fruit instead of money would be an insult, I'd rather take nothing in compensation. Plasmic Physics (talk) 05:21, 5 November 2017 (UTC)

• It's purely a matter of convenience. Animals would be given money too if only they could be persuaded to work for it. Looie496 (talk) 13:58, 5 November 2017 (UTC)

Volunteers may only eat what they are given (if they smuggle in food they may be discharged and/or not paid).[6] This is because diet affects how the body metabolises the trial drug. 86.155.148.59 (talk) 15:39, 5 November 2017 (UTC)

Like domestic animals in general, animals used in research are completely dependent on their human carers for all their needs, so food or water can be withheld for a period before the experiment so they have an incentive to work for it. If you could starve your human subjects in the same way they would also be willing to work for their food but as human subjects take part voluntarily you can't normally confine them and withhold food from them and so you have to find a different way to encourage them to take part. Usually the main drivers are altruism, simple curiousity or the possibility of helping to find a cure for a disease from which they suffer, and any money paid is to offset any financial losses they may incur, such as wages lost and/or travel expenses. Richerman (talk) 00:36, 6 November 2017 (UTC)

Does a couple of months' worth of grocery vouchers count? Plasmic Physics (talk) 19:15, 6 November 2017 (UTC)

Going back to my original comment, we're looking at a number of different concepts. There's reimbursement for out-of-pocket expenses, compensation for the value of a participant's time and effort, and (what I will call) rewards which might be motivational 'prizes' for completing tasks or accomplishing goals in an experiment—likely a psychology experiment. The original poster conflates a "reward" (the food in a maze, for a mouse) with "compensation"-type payment (money a human subject receives for participating in a study). Those are different things, with different consequences. Generally speaking, lab animals don't receive "compensation"; they get dropped in the maze whether they want to or not. TenOfAllTrades(talk) 19:37, 6 November 2017 (UTC)