Wikipedia:Reference desk/Archives/Science/2020 July 27

= July 27 =

Teeth
Why are teeth so numerous? Why have so many teeth, rather than just two, big, U-shaped teeth? And, what is with them being so maintenance-heavy? Why do they rot so easily? — Preceding unsigned comment added by 2602:252:D14:F900:A5A7:1F:C2F2:B639 (talk) 03:59, 27 July 2020 (UTC)
 * Cause our teeth are shit and should've been encased in silicon oxide (we might need to swallow sand occasionally to get enough silicon) but evolution isn't to make life easier, it's the side effect of accidental mutations sometimes getting popular by fertility or even luck and even worse, the logical result is reproducing to death. This is why pigeons are hungry, if there were any more that many would die, if they don't they just fuck till there *are* too many. Just because other lifeforms have silicate shells doesn't mean we'd evolve them too. Sagittarian Milky Way (talk) 05:56, 27 July 2020 (UTC)
 * The interrogative adverb "why" has several meanings. See also Teleology in biology and Poor design. If humans had just two, big, U-shaped teeth, they'd have a real problem though, if one broke. You can go on living happily with quite a few fewer teeth. Human teeth have not co-evolved with the typical human diet, which involves much less gnawing and much too much sugary stuff, and thus (without meticulous dental hygiene) much more dental plaque buildup and a happier environment for the bacteria causing tooth decay than when mammal teeth evolved. Here is a link to an article on the topic from the Scientific American. --Lambiam 08:34, 27 July 2020 (UTC)
 * According to the link, our current diet is too soft and sugary for our teeth. I would ask "why so soft and sugary?", but it is probably best if I do not ask: I somehow suspect that the [rabbit hole] is very, very deep. 2602:252:D14:F900:4D59:D5D9:8F1C:E9B7 (talk) 21:11, 27 July 2020 (UTC)
 * Not really, the answer is "agriculture". Most of what we eat is man-made; we've selectively bred it to be more nutritious and easier to eat. Compare maize or bananas with their wild relatives (the articles have pictures). --47.146.63.87 (talk) 23:25, 28 July 2020 (UTC)
 * Might as well ask why we even need teeth. We have blenders. Just turn everything into soup or paste and do away with teeth all together. 97.82.165.112 (talk) 11:15, 27 July 2020 (UTC)
 * Also bear in mind that humans need "four types of teeth: incisors, canines, premolars, and molars, which each have a specific function. The incisors cut the food, the canines tear the food and the molars and premolars crush the food."--Shantavira|feed me 11:30, 27 July 2020 (UTC)
 * We inherited the layout from our primate forbears and so on down the evolutionary chain. Tortoises have two bony ridges that function like the OP's "U-shaped teeth", but lack the ability to chew. Alansplodge (talk) 13:40, 27 July 2020 (UTC)


 * See also here. Count Iblis (talk) 10:33, 31 July 2020 (UTC)

Solar Panels
I have heard recently in conversation that Solar Panels being the solution to our future energy problems may be a false economy. I recall the Palm Oil Solution in the late 90’s which has turned from a blessing to a curse and wonder if what I heard is accurate…Google searches seem to provide me with multiple false results. I was told that Solar panels for industrial use, e.g. those use in massive farms to power cities, only last a few years at which point they need to be entirely replaced. The now useless panels can’t be fully recycled or recycled at all and will end up in landfills, bleeding harmful chemicals and causing more damage that what they are supposed to prevent. Is this true? What other solutions are there? The only other I have heard is that of harnessing the power of Ocean waves; yet I have heard very little about this. Why? Why would we take the gargantuan step to move from coal or nuclear power generation to solar, if this is not truly a solution, if we’re going to make the change why not do it properly the first time? What other solutions are there and why are these not being employed? Thanks. — Preceding unsigned comment added by 31.53.187.190 (talk) 12:25, 27 July 2020 (UTC)
 * Don't believe every anti-environmental thing without asking physicists or something first (I guess we're probably good enough). If you were Israeli or Palestinian you wouldn't believe every bad thing said about your people without consulting reliable sources would you? That should apply to anything with haters. Sagittarian Milky Way (talk) 13:30, 27 July 2020 (UTC)
 * ...and that's why I'm asking here. — Preceding unsigned comment added by 31.53.187.190 (talk) 14:22, 27 July 2020 (UTC)
 * One excellent source of information on energy is the ... Energy Information Agency, an independent analysis agency under the United States Department of Energy.
 * Every year they publish an Annual Energy Outlook, including projections about the economic and physical developments for short and long term. "The Annual Energy Outlook presents an assessment by the U.S. Energy Information Administration of the outlook for energy markets through 2050."  This is a largely factual assessment.
 * If you are looking for an introduction to a policy assessment, first you have to decide whose policy opinions you trust. Where do we begin on such a broad topic?
 * If you are a late-stage learner, we can point you to published books, journals, and scientific reviews. In almost any public library's nonfiction section, you will find a lot of writing on the topic of energy policy.
 * If you are an early-years student and looking for information, we should point you toward appropriate college-level classwork and the resources therein.
 * One can pursue many years of full-time education and still only have received a brief introduction to energy and environmental policy. For example, the first- and second-year undergraduates at Stanford might take Sustainable Energy for 9 Billion, ... and if they are interested, they might pursue three more years of undergraduate specialization in the environmental and energy curriculum, and then proceed toward five or six more years in post-graduate research in environmental or energy topics.
 * The point, though, is that you are not going to find an easy answer to this topic. We cannot and should not summarize it into a sound-bite.
 * For something a little bit topical, here is a Conversation with Steven Chu: Lessons from the Past and Energy Storage for Deep Renewables Adoption, part of the Precourt Institute for Energy's Global Energy Forum, a "virtual dialogue" filmed in the context of the COVID-19 Pandemic. Steven Chu is a physicist, a Nobel laureate, and served under President Obama as the United States Secretary of Energy.  One time he even shot up some atoms with a laser, so this is a guy who doesn't mess around.
 * Nimur (talk) 16:12, 27 July 2020 (UTC)


 * From an economic perspective: Many manufacturers seem to offer a warranty for 20-25 years on panels (normally, that they will still perform at 80% nominal level after that time). For comparison: Normal large power-plants are often designed for a 30 year life span. At the moment, it seems that solar panels are more often replaced because newer generations offer significantly better performance, not because they are "worn out". Any product can be recycled. None can be recycled perfectly. The degree to which they are recycled depends on the economic and regulatory environment. A German research project claimed full-cycle recycling rates (including production waste) of about 95% back in 2010 . --Stephan Schulz (talk) 16:54, 27 July 2020 (UTC)


 * Domestic panels have a 20 year 80% warranty typically. In 4 years I have seen no drop off in performance. I also have some 30 year old panels that seem to be about 10% efficient, which may well be what domestic grade was back then. So it would seem that claims of a lifetime of 'a few years' are rather selective at best. Greglocock (talk) 22:33, 27 July 2020 (UTC)


 * Solar panels are pretty durable, but large battery storage systems may be more of a problem. 2601:648:8202:96B0:0:0:0:5B74 (talk) 06:03, 28 July 2020 (UTC)


 * The Lifespan of Solar Panels quotes a couple of studies which show a long term annual loss of between 0.5% and 0.7%. It also describes the 2010 discovery of a 1946 solar panel (actually a solar globe) which still worked. Alansplodge (talk) 20:14, 28 July 2020 (UTC)
 * There are ways other than batteries of storing power. Cool fact: superconducting magnetic energy storage can store electrical power indefinitely, since superconductors have no resistance. The only problem is maintaining the superconductive state. The choice between different methods is an engineering and economic problem. For instance, battery systems are nice for stabilizing electrical grids since they can be discharged at-will; there's no "lag time" like that needed to spin up an electrical generator. --47.146.63.87 (talk) 23:32, 28 July 2020 (UTC)
 * I remember - but cannot point to the source - a claim that momentum wheels have 85% efficiency and can give back the stored energy at will, but are not economically feasible since it requires costly generators. אילן שמעוני (talk) 08:45, 31 July 2020 (UTC)
 * That would be flywheel energy storage. --47.146.63.87 (talk) 00:40, 2 August 2020 (UTC)