Wikipedia:Reference desk/Archives/Science/2019 August 15

= August 15 =

That Russian rocket explosion
I wonder about the Russian rocket that exploded. They said it was nuclear, that is the warhead, I presume, or maybe the propulsion system? That would have been totally crazy. Let's assume that was the warhead. Normally nuclear weapons do not explode. There is no reason for them to do this. A nuclear warhead is pretty much like a nuclear bomb only propelled with a reactive force. Everyone knows how uranium and plutonium bombs worked in 1945 in Japan. The Russians have been saying their weapon is NEW. In what sense? Perhaps it was a dirty bomb? They aren't new. Is it possible that they synthesized transuranial element and made a bomb out of it. What's the advantage? Transuranials are usually synthesized in minute quantities.

WSJ reported that the Russian government ordered the local population in Severodvinsk or perhaps even Archangelsk to move out. So there is a considerable fallout of radioactivity. Then it is another Chernobyl. Then that area will be cleaned in 10 million years. AboutFace 22 (talk) 01:59, 15 August 2019 (UTC)


 * It was a test rocket, so the warhead would have hopefully been a dummy, containing neither nuclear nor conventional explosives. The "nuclear" part of a nuclear-powered cruise missile is the power plant (although this rocket is believed to be a test version of a planned nuclear-powered and nuclear-armed cruise missile). Anyway, the general idea of these things (see Nuclear-powered aircraft, including the section on Russian projects) is that similar to how a nuclear reactor normally works by dumping heat into coolant, the nuclear reactor on this missile would heat up intake air, and use it as an inert rocket propellant. The main advantage is the time that can be spent in powered flight. ICBMs have a fairly limited capacity to adjust course, and spend a lot of time just coasting on a predictable trajectory. A nuclear-powered rocket does not have that limitation. It can adjust its course continuously throughout the flight to avoid countermeasures, and fly a non-obvious route to avoid early detection. That is, it does not need to make a beeline from the launcher to the target, it does not need to achieve orbit to circumnavigate the globe, and its target can be changed on the fly. I mean, so many advantages. Just the one little disadvantage that it's a flying nuclear disaster waiting to happen. Anyway, it's "new" in that it's a new design. Someguy1221 (talk) 02:27, 15 August 2019 (UTC)


 * You can't count on the Russians to use common sense and test things in a safe way. The Chernobyl disaster is a prime example, being a catastrophically failed test. One might argue that was under the bad old days of the Soviet Union, but the current rather authoritarian Russian government has in common the feature that any dissenters can simply be arrested or poisoned, with no need to reform safety procedures. SinisterLefty (talk) 03:00, 15 August 2019 (UTC
 * +1 Someguy1221. You can even bet that the flying nuclear disaster waiting to happen, that is, "upon impact or destruction the nuclear engine spreads radioactivity all over the place as a dirty bomb would" part was counted as another advantage, not disadvantage. Gem fr (talk) 09:05, 15 August 2019 (UTC)


 * Here's a relevant article:. Note that there really isn't a safe way to test this device, as you would need to catch it to stop it from spewing radioactive isotopes all over the target. This is part of why the US stopped development of such a weapon in the 1960s. In the end, assuming it is never used, it is likely to kill more Russians than their enemies.  SinisterLefty (talk) 03:09, 15 August 2019 (UTC)


 * No-one knows anything. Anyone who knows isn't telling. The Russians are past secretive and well into deceptive. The most likely source to tell us anything both detailed, competent and trustworthy would be Bellona.  WP's article is at 9M730 Burevestnik, but that's more of an edit-war than an article. Andy Dingley (talk) 12:43, 15 August 2019 (UTC)
 * I generally agree with Andy Dingley's sentiments: there is a deficit of unbiased, referenced, factual information from reliable sources; and there is significant reason to believe that this issue would be intentionally misreported in order to confuse and distract; in other words, we have a dearth of good information, and we plenty of misinformation and disinformation.
 * One other resource that might be useful is the Federation of American Scientists, a "think tank" who use science and scientific analysis to attempt to make the world more secure. They often present useful, factual analysis on topics like this.  If you haven't already read their website's 2018 Nuclear Posture Review review, it's a pretty good set of background information that helps to understand context around American policies and technologies, and American assessments of Russian policies and technologies.
 * It might be premature to read the review of the review... until you actually read the Nuclear Posture Review.  From the executive summary:
 * While the United States has continued to reduce the number and salience of nuclear weapons, others, including Russia and China, have moved in the opposite direction. They have added new types of nuclear capabilities to their arsenals, increased the salience of nuclear forces in their strategies and plans, and engaged in increasingly aggressive behavior, including in outer space and cyber space... There now exists an unprecedented range and mix of threats, including major conventional, chemical, biological, nuclear, space, and cyber threats, and violent non- state actors. These developments have produced increased uncertainty and risk.
 * My point is, there is a large amount of information available, but you need to be constantly aware that this type of information shouldn't always be accepted at face value.
 * Nimur (talk) 21:40, 15 August 2019 (UTC)


 * The weaponizing of cyberspace does include the US, see Stuxnet, which seemed to be a joint US/Israeli op. (It did seem to be used for a good cause, at least, slowing Iran's nuclear weapons program.) SinisterLefty (talk) 01:27, 16 August 2019 (UTC)


 * The Bulletin of the Atomic Scientists is likely to more informative, and quicker, than FAS, although both would be worth reading. Sadly I stopped my BAS subscription when they stopped the paper version. Andy Dingley (talk) 21:48, 15 August 2019 (UTC)

Extremely cold subarctic climate (Dfd/Dsd/Dwd) in the Köppen classification
Hi all,

I have a question about the rationale for the subtype d in the continental climate classification (Dfd/Dwd/Dsd). The only difference with c (Dfc/Dwc/Dsc) is the extremely cold winter, with the threshold at -38C for the coldest month (c only requires below 0 or -3C depending on sources).

What happens at -38C? Apparently, there is taiga in D?d climates too (e.g. Verkhoyansk, Russia), but is there any marked difference in fauna/flora that justifies the d subtype?

134.171.85.176 (talk) 05:42, 15 August 2019 (UTC)


 * Permafrost ? I don't know exactly what temps are required to maintain that, but it's quite a significant difference from normal soil, affected all construction, excavation, mining, etc. As for plants, that means roots and bulbs can't grow deep enough to avoid freezing, so would make it hard to survive winter for perennial plants. For animals, hibernation may still be possible, if they dig a den in the soil during summer, above the permafrost zone, and insulate it well enough (with fur maybe) to survive winter there. SinisterLefty (talk) 12:52, 15 August 2019 (UTC)
 * Permafrost also exist in -c, which is quite logical since it doesn't require "extremely cold winter", just an average yearlong slightly under 0. So it most be something else. No idea what happens at the -38C threshold as opposed to, say, -20C, which is already a killer for most species Gem fr (talk) 15:16, 15 August 2019 (UTC)
 * I've tried to dig in the original papers by Wladimir Köppen, but could not find any explanation. The -d is absent in the 1984 & 1900 papers, present in 1918 & 1936 ones. There is a paragraph explaining the difference between Dfc/Dwd (snowy not so cold, dry winter very cold) in the 1918 paper but the reason for the threshold is not stated.  Interestingly, other thresholds are well stated (For instance the 10⁰C for D v. E is linked to the tree line, which is clearly stated in the 1884 and 1900 papers).  — Preceding unsigned comment added by 134.171.85.176 (talk) 23:42, 15 August 2019 (UTC)

why is britain suddenly the tornado capital?
In the newsmedia lately Britain supposedly gets more tornadoes per unit area than Kansas. Is this true or are the just quoting each other, maybe because of deadline pressures? Kansas has slightly more area than Britain, and gets like 50 tornadoes a year, while the news media admits that Britain gets 30 to 40/year. Anyway Oklahoma has less area than Britain and gets 60/year. It may not be something to be patriotic or proud of, but accuracy in little things can affect a journalist’s reputation.Rich (talk) 05:56, 15 August 2019 (UTC)
 * Can you link to the newsmedia source for your assertion? That way we can see exactly what they are claiming. I suspect it comes down to how they are defining a tornado.--Shantavira|feed me 08:01, 15 August 2019 (UTC)


 * The UK gets an average of 30-50 tornadoes a year. That’s more tornadoes per land area than anywhere else in the world (except – weirdly – the Netherlands.) For a more scholarly article see: where it says


 * "Few of the storms were very strong however, with 95% classified as being F0 or F1 (or estimated wind speeds of up to 112 mph) with the remainder F2 (estimated wind speeds up to 157 mph). There were none any stronger than that, such as the devastating F5s (estimated wind speeds over 300 mph) that can hit the United States and cause widespread loss of life and damage to property."
 * There's nothing new about this, it's been one of those oft quoted "did you know" facts for years. It usually comes up when a tornado has caused some damage somewhere in the UK

————————-
 * So Kansas and Oklahama both have smaller areas than the total of the UK, and but both have more and stronger tornadoes. Is their point that the UK and Netherlands are countries, rather than parts of a country? But the newscquote above doesn’t say country, it says “per land area.”Rich (talk) 20:16, 15 August 2019 (UTC)
 * If their point is they define a land area to be a total land mass surronded by water, like an island or a continent, that can’t be consistent, because then they bring in the Netherlands, which is not completely surrounded by water.Rich (talk) 20:34, 15 August 2019 (UTC)
 * This is kind of an illustration of the old saying, "Figures don't like, but liars do figure." ←Baseball Bugs What's up, Doc? carrots→ 01:20, 16 August 2019 (UTC)
 * It seems more likely that they're using nation-states. Per square x the US's tornadoes are going to be wildly reduced due to the immense size of places like Alaska, which get fewer tornadoes. Imagine a tiny country that's only one meter by one meter in size. If they got one tornado this year, they could say that they experienced one tornado per m^2 - thousands of times more than the USA in total (or, indeed, even the heart of tornado alley, on a per meter basis). Matt Deres (talk) 19:57, 16 August 2019 (UTC)

Binge-eating cookies: Does the body pass through excess calories?
I find many contradictory views and opinions online about this.

Thought experiment: suppose a person is reasonably healthy, constant-weight, consuming a 2000 calorie/day diet that includes 1900 calories of regular food and one 100-calorie cookie, each day.

Let's say that over one 20-day period, the person redistributes the 20 cookies to consume them all on the first day, and then diligently consumes only the regular 1900-caloried diet, and nothing else, for the other 19 days. Total calories consumed over 20 days is the same as if one cookie was consumed per day during the same period.

Ignoring the glycemic response from this, will there be any difference in weight at the end of the period?

My thinking is, the digestive system isn't 100% efficient and won't be able to store the energy from all those cookies the first day, so many of the calories will pass through and out, so the net effect is to process less calories over the test period. At the extreme, eating 40,000 calories on one day and starving for 19 days will probably result in weight loss.

If that's true, then is there some threshold level beyond which eating more calories won't make a difference?

On the other hand, alternating between binge-eating 4000 calories one day and fasting the next also gives 2000 calories/day on average, but it seems to me that this sort of regimen might improve efficiency, training the body to store more energy for the following day's fast. Maybe the way calories are distributed matters.

Have there been any studies published on this? ~Anachronist (talk) 21:02, 15 August 2019 (UTC)


 * The body does have a limit, but that limit also changes due to behavior. General reference on calorie absorption - The rate at which your body is able to absorb calories from a meal is heavily influenced by many factors related to both the person eating the meal and the content of the meal itself. Calories that are not absorbed are usually consumed by the microbiome, though some fats/lipids/sugars make it all the way through. There have been a variety of studies trying to measure this. This one concluded that consuming basically just sugar-water, the average person could absorb about 200 calories per hour. There's not a set time limit on absorbing these, though. The digestive system can actually slow the passage of food and drink in response to a calorie rich meal. Just so many variables! There is a hard limit at some point where you are essentially saturating nutrient transporters in your intestine, but it's known that habitual overeaters seem to have a greater capacity to absorb nutrients. So while 200 calories in an hour = 4800 calories in a day might be the max for getting calories from sugar water for the typical person in that study, it might not be the max for someone who is morbidly obese and always consumes 30,000 calories a day, or for an olympic athlete who consumes 12,000 calories a day while training. And of course the mechanisms of calorie uptake are separate for sugar, protein and fat, so that's not the total max. Here is a much more detailed review of just sugar absorption, including discussion of various animal studies. Also in this study, specifically on patients who habitually binge-and-purge, the data shows that the habitual binge-and-purgers were able to eat several times more than the controls, and actually had better nutrient absorption. Someguy1221 (talk) 01:18, 16 August 2019 (UTC)


 * pretty sure Ignoring the glycemic response from this cannot be done.
 * (digesting issues have been rise above). My understanding (2 cents) is that, while we know a lot about, say, glycogen or fatty acid metabolisms, the way they interact is still too complex for us figure out, and it depends a lot on the specific case. Whether the extra cookies are turned into glycogen or triglyceride would probably matter, for instance (again, just 2cents to highlight how complex properly answering is) Gem fr (talk) 07:38, 16 August 2019 (UTC)


 * Somehow Matt Stonie does manage to stay slim. Count Iblis (talk) 00:28, 18 August 2019 (UTC)

Light transmission
Why can't light pass through metals? 80.2.20.134 (talk) 23:45, 15 August 2019 (UTC)
 * The free electrons prevent electromagnetic waves (in particular visible light) to penetrate deep into the metal. See also Faraday cage (blocking of radio waves).  — Preceding unsigned comment added by 134.171.85.176 (talk) 23:57, 15 August 2019 (UTC)


 * A sheet of metal that's sufficiently thin might allow some light to pass through. (I know because my high school chemistry teacher said so.) ←Baseball Bugs What's up, Doc? carrots→ 01:15, 16 August 2019 (UTC)
 * Gold leaf, for example, is translucent. --jpgordon&#x1d122;&#x1d106; &#x1D110;&#x1d107; 01:33, 16 August 2019 (UTC)
 * One-way mirrors and transparent conducting films can be made from (semi)transparent layers of metal. The key is to get the layer reeeeeeeeally thin. DMacks (talk) 08:30, 16 August 2019 (UTC)


 * It does. But it's attenuated very quickly.  Thin enough films will transmit appreciably, although this is thinner than gold leaf (they're so thin they need to be deposited on something else).  Our articles on penetration depth and skin effect might cover some of this.
 * To study the maths of this, consider light as an electromagnetic wave. When attenuated, this drops in intensity exponentially with depth, but it's not instant. Andy Dingley (talk) 11:22, 16 August 2019 (UTC)


 * See also https://phys.org/news/2009-07-transparent-aluminium-state.html and https://www.nature.com/articles/nature10741 (real-life experiments referenced in our article about the fictional material transparent aluminium). {The poster formerly known as 87.81.230.195} 2.123.24.56 (talk) 14:03, 16 August 2019 (UTC)
 * Or transparent aluminum, in Star Trek IV. ←Baseball Bugs What's up, Doc? carrots→ 14:38, 16 August 2019 (UTC)
 * Um, that is precisely the subject of the Wikipedia article I linked to immediately above. {The poster formerly known as 87.81.230.195} 2.123.24.56 (talk) 23:17, 17 August 2019 (UTC)
 * I don't recall Scotty pronouncing it that way. ←Baseball Bugs What's up, Doc? carrots→ 11:32, 20 August 2019 (UTC)
 * Advances towards transparent aluminum exist. Last I've read, experiments can make aluminum transparent to ultraviolet light for a very short time. Both the bandwidth that can pass through the structure and the time it is transparent have increased over the years. 135.84.167.41 (talk) 18:46, 16 August 2019 (UTC)
 * Is opaque aluminum even actually better (besides uselessness as a window) than some bulletproof glass composite sandwich with coatings that was present day tech before the scriptwriter had thought of transparent aluminum? Why not just use that? Sagittarian Milky Way (talk) 14:42, 18 August 2019 (UTC)