Wikipedia:Reference desk/Archives/Science/2018 June 27

= June 27 =

Post-merger LIGO data
Does the LIGO data from after a black hole merger support either one of the following, and if so does that resolve the inner lives of black holes?


 * Post-merger two point masses continue into each other and become a single point mass

or


 * Post-merger two blobs simply become one big blob with no further evolution.

Hcobb (talk) 00:16, 27 June 2018 (UTC)


 * Define "post-merger". The LIGO data fits extremely well with the inspiral-merger-ringdown model that was constructed from numerical simulations of general relativity. The black holes don't instantly become one sphere after their horizons touch - a thread forms between them that expands, and the black hole becomes an elongated sphere, which then oscillates between that and a flattened sphere, emitting more gravitational waves until it settles into a final state. You can never observe events occurring beyond the event horizon, and if such a thing was consistent with LIGO data, you can bet there would be a lot of noise about that. Someguy1221 (talk) 01:12, 27 June 2018 (UTC)


 * Our article is at binary black hole. The ring down phase gets exponentially weaker over time, and it should really be gravitationally red shifted for ever. So basically the signal gets too weak to detect, and there is no detection of anythiing inside the event horizons. Graeme Bartlett (talk) 01:52, 28 June 2018 (UTC)

Electrons
I'm looking for evidence that the electron is not in fact a particle but a bundle of electromagmetic energy vibrating  at the speed of light. Can anyone refer me? 80.2.21.17 (talk) 01:39, 27 June 2018 (UTC)


 * Well that's not what the electron is, so why would there be anywhere to refer you to? It's also not even clear what "a bundle of electromagnetic energy vibrating at the speed of light" even means. It sounds like one of those gobbledygook chains of sciency words that's so vague it's not even wrong. Someguy1221 (talk) 03:03, 27 June 2018 (UTC)


 * Wave–particle duality might be of interest. —107.15.157.44 (talk) 03:16, 27 June 2018 (UTC)

An electron has finite mass that cannot move as fast as the speed of light, though accelerating an electron causes Bremsstrahlung i.e. "braking radiation" emission of photons that do travel at light speed in a vacuum. DroneB (talk) 17:21, 27 June 2018 (UTC)
 * I would kindly suggest to read our article about confirmation bias. Online search engines are very good at finding "evidence" for anything no matter how far-fetched, but setting out to search evidence for a particular position is not how you inform yourself about the validity of that position. Tigraan Click here to contact me 08:21, 27 June 2018 (UTC)


 * The current state on the debate relating to quantum wave-particle duality is concisely discussed here:. It references the following study which concludes: "According to our analysis, the duality principle in its standard form is safe and sound, but our duality relation remains to be thoroughly tested.":. 2606:A000:1126:20CE:0:98F2:CFF6:1782 (talk) 18:54, 27 June 2018 (UTC)
 * The first thing you should do is read these two pages: . The main point is, if you don't have a mathematical framework worked out then all you have is a vague guess, which we call a hypothesis. The next thing to do is to come up with ways to test that hypothesis. What observations are predicted if your proposal is true? Just as an interested layman, the thing that jumps out at me is that, assuming you mean "vibrating at the speed of light in a vacuum", this I believe violates special relativity. The electron has rest mass, which means it can't attain c, the speed of light in a vacuum. Admittedly I'm not completely sure if something "vibrating" at that speed violates it, but I'm not sure that statement has any real meaning. What frequency do you think it's vibrating at? Does this relate to the electron's de Broglie wavelength? If you really want to pursue this, you need to work out what your prediction implies. Also, nothing personal, but be prepared to accept that you're probably wrong. I'm assuming you don't have a physics background, and it's very unlikely for anyone without one to develop some groundbreaking new physics. But don't let this discourage you from learning more. And feel welcome to ask us for help in learning more. --47.146.63.87 (talk) 23:34, 27 June 2018 (UTC)
 * For one thing, by definition, energy cannot exist by itself - it is a quantifiable attribute of something. Sure, matter can vibrate at the speed of light, but only as long as the amplitude is less than the Planck length. Plasmic Physics (talk) 05:15, 29 June 2018 (UTC)

Neuroscientific plausibility of BLIT (short story)
David Langford's BLIT and its companion stories describe images which cause instant death (or at least harmful symptoms) when viewed by "crashing" the brain. Given what is known about visual processing, is it plausible that viewing an image could kill someone as described by Langford? 169.228.167.108 (talk) 03:18, 27 June 2018 (UTC)
 * It would be quite a stretch, but in sci-fi that is common. One could imagine certain images triggering a spontaneous fatal occipital epileptic event. —2606:A000:1126:20CE:0:98F2:CFF6:1782 (talk) 04:48, 27 June 2018 (UTC)


 * There are several earlier sci-fi treatments of this. Victor Contoski Wrote "Von Goom's Gambit" in 1966, wherein any chess master who discovers this particular chess sequence is so horrified that death immediately follows. Stephenson's 1992 Snow Crash is about a linguistinc "virus" crashing the brain's operating system. -Arch dude (talk) 05:20, 27 June 2018 (UTC)
 * Or Monty Python's "Funniest Joke in the World" (1969). —2606:A000:1126:20CE:0:98F2:CFF6:1782 (talk) 05:24, 27 June 2018 (UTC)
 * Zwei peanuts ver valking down ze Strasse, von vas assaulted. Peanut. Sagittarian Milky Way (talk) 18:04, 27 June 2018 (UTC)


 * Long story short: no, there is zero realistic possibility of this happening. This is a trope which has gained currency in science fiction via the same route as a great many misrepresentations of the basic mechanics of the human brain: namely, the notion that the brain might function fundamentally like a digital device designed for computation.  In reality, the brain is a neural net (which, from the framing of your question, you surely understand) and thus is not capable of "crashing" in the same way as a digital computer would if provided with an input which leads to a fatal logical error.  With regard to a still image, there is no such thing as any combination of photonic stimuli comprising any received image on the retina which is capable of causing neurological damage when processed higher in the visual cognition system.


 * As one respondent noted above, there are pre-existing neurological conditions (epilepsy being the best known) which can trigger seizure with the right amount and type of stimuli, but typically movement or oscillations in luminosity are the triggering factor; there are rare instances where a threshold of luminosity or a specific level of a particular kind of underlying stimulation are sufficient to the induce seizure, but not cases where a specific still image does so where no other image in existence would. Even then, seizures typically are not fatal and they do not generally cause direct damage to brain tissue (they can cause very significant or in rare cases fatal indirect damage from striking one's head or from broader physiological complications that result from the seizure).  Snow let's rap 08:05, 4 July 2018 (UTC)

Is there any way to see scientifically plausible Earths that almost were?
Is deriving today's (or even the Cambrian's?) world map from only a near-omniscient knowledge of 4 billion BC and the laws of physics the realm of the butterfly effect? Planetesimal orbits/impacts are only probabilistic beyond a few million years and many left lava seas of pierced crust so maybe right? Then is there a way I could see a scientifically accurate or at least plausible simulated world map with the minimum change needed to butterfly effect away the current world map into randomness? Are these computationally cheap enough to make to do statistical analyses? i.e. is the longest continent of 4.56 billion year old Earths more likely to be longer or shorter than current Eurasia, how often are the South Poles of 4.56 billion year old Earths in ocean trenches, odds of unbroken equatorial current, smallest world's largest continent in X simulations.. Sagittarian Milky Way (talk) 17:55, 27 June 2018 (UTC)
 * Short answer: no. 2606:A000:1126:20CE:0:98F2:CFF6:1782 (talk) 20:28, 27 June 2018 (UTC) ... CAUTION: attempting to read above query may result in spontaneous crashing of the brain's operating system
 * I've seen the current continent configuration my whole life, I just wanted to see another one. One of the more likely ones, not "perfectly square Pangea" or "roll dice, each map pixel under 3 is land". Sagittarian Milky Way (talk) 01:53, 28 June 2018 (UTC)
 * Here's one purported "scientific" what-if alternative Earth map: Daily Mail (ignore article on Gabrielle Union in nude bikini). —2606:A000:1126:20CE:0:98F2:CFF6:1782 (talk) 02:21, 28 June 2018 (UTC)
 * Please be aware the Daily Fail is an odious publication filled with hate speech. It is also widely known for it's terrible reporting of anything vaguely scientific. You really shouldn't link to it. Fgf10 (talk) 07:58, 28 June 2018 (UTC)
 * The article about Gabrielle Union seems scientific enough. ←Baseball Bugs What's up, Doc? carrots→ 08:37, 28 June 2018 (UTC)
 * With this sort of thing, it's generally best to look for the actual paper. It appears to be this one . Unfortunately most of the links there don't work except for the paper itself. Still the link to the UoS PR does work and seems to confirm that image came from the researchers and isn't something the Daily Mail made up. It's possible the supplementary material is here [//pubs.geoscienceworld.org/gsa/geology/article-abstract/42/3/211/131501/oblique-rifting-of-the-equatorial-atlantic-why], with many journals it would be nowadays but I don't have access to check. Nil Einne (talk) 19:16, 30 June 2018 (UTC)


 * Continental drift appears to be driven by convective upwelling currents in the mantle. Convective upwelling is notoriously chaotic in the technical sense of the term, so any sort of actual prediction is pretty much a non-starter. It might be possible to build a simulation that would be realistic, but not not one that would yield Earth's actual continents over time. Other processes that result from convective upwelling include Mesoscale convective systems of thunderstorms and boiling liquids in a pot. The weather guys cannot predict the locations of thunderstorms within a mesoscale system, but they can tell us roughly what percentage of the area will have the storms. Similarly, you cannot produce a model that will show exactly where the steam bubbles will be in a roiling pot, but you can describe them statistically. -Arch dude (talk) 03:36, 28 June 2018 (UTC)


 * The mechanisms driving continental drift are not understood well enough to support long-term modeling. It is possible to make predictions for a few million years by assuming that the continents will keep moving in the same way they are now, but the mechanisms that cause continents to change their speed and direction of motion are very poorly understood. Looie496 (talk) 13:23, 28 June 2018 (UTC)


 * 4.56 billion years ago the Earth was a boiling ball of liquid rock. Count Iblis (talk) 15:44, 28 June 2018 (UTC)
 * "4.56 billion years ago the Earth was a boiling ball of liquid rock" is one theory. Other sources propose that the Earth has never been completely smelted 194.174.76.21 (talk) 16:34, 28 June 2018 (UTC) Marco Pagliero Berlin
 * For example, Gary Larson indicated that the earth was only half-baked. ←Baseball Bugs What's up, Doc? carrots→ 20:09, 28 June 2018 (UTC)
 * See here: "The energy associated with giant impacts is large enough to generate global magma oceans during Earth's accretion. However, geochemical evidence requiring a terrestrial magma ocean is scarce. Here we present evidence for at least two separate magma ocean outgassing episodes on Earth based on the ratio of primordial 3He to 22Ne in the present-day mantle. We demonstrate that the depleted mantle 3He/22Ne ratio is at least 10 while a more primitive mantle reservoir has a 3He/22Ne ratio of 2.3 to 3. The 3He/22Ne ratios of the mantle reservoirs are higher than possible sources of terrestrial volatiles, including the solar nebula ratio of 1.5. Therefore, a planetary process must have raised the mantle's 3He/22Ne ratio. We show that long-term plate tectonic cycling is incapable of raising the mantle 3He/22Ne ratio and may even lower it. However, ingassing of a gravitationally accreted nebular atmosphere into a magma ocean on the proto-Earth explains the 3He/22Ne and 20Ne/22Ne ratios of the primitive mantle reservoir. Increasing the mantle 3He/22Ne ratio to a value of 10 in the depleted mantle requires at least two episodes of atmospheric blow-off and magma ocean outgassing associated with giant impacts during subsequent terrestrial accretion. The preservation of a low 3He/22Ne ratio in a primitive reservoir sampled by plumes suggests that the later giant impacts, including the Moon-forming giant impact, did not generate a whole mantle magma ocean. Atmospheric loss episodes associated with giant impacts provide an explanation for Earth's subchondritic C/H, N/H, and Cl/F elemental ratios while preserving chondritic isotopic ratios. If so, a significant proportion of terrestrial water and potentially other major volatiles were accreted prior to the last giant impact, otherwise the fractionated elemental ratios would have been overprinted by the late veneer." Count Iblis (talk) 21:19, 29 June 2018 (UTC)


 * Plate reconstruction explains some of the ways that we try to move backwards in geological time in an attempt to understand the past configuration of continents and oceans. The uncertainties get bigger the further you go back, so we can have no more than an educated guess as to how things were more than about a billion years ago (roughly when the supercontinent of Rodinia was formed). Trying to model alternatives when moving forward in time from any point in the past (exploring other locations for destructive plate boundaries for instance) or even from the present, involves huge uncertainty - see for example Pangaea Ultima. Mikenorton (talk) 15:47, 29 June 2018 (UTC)

Giraffe's Feet
I read in a paper: "Although the giraffe's toes are indeed separate from one another, a thin layer of spongy tissue sits beneath the toes and attaches them one to the other." I would be grateful if a user could please inform me whether or not this statement is correct. Thank you.Simonschaim (talk) 18:19, 27 June 2018 (UTC)
 * See even-toed ungulate, the group of which giraffes are a member. They all have the same basic foot anatomy. --47.146.63.87 (talk) 23:10, 27 June 2018 (UTC)
 * Neither of those articles (nor any other I have so far found) address the query. It might help us to assess the statement if Simonschaim tells us where it was found. {The poster formerly known as 87.81.230.195} 2.122.0.113 (talk) 12:38, 28 June 2018 (UTC)
 * It could be http://www.dailyhalacha.com/m/halacha.aspx?id=502 But the photos of giraffes' feet I found on the net ( https://www.google.com/search?q=%22giraffe%22+%22hooves ) show clearly separated nails/hooves, even if the toes are not. It is possibly a question of definig toes vs. hooves? Which question I think is rather clear in English, but it is maybe not so clear in the language of the Torah?194.174.76.21 (talk) 16:28, 28 June 2018 (UTC) Marco Pagliero Berlin