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2. ## MigL

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3. ## studiot

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## Popular Content

Showing content with the highest reputation since 04/25/20 in all areas

1. 7 points

2. 4 points

## 1. Thermodynamic work

A question about a sign convention that leads to a lot of confusion. This is not the only instance multiple sign conventions in Science. In this case it is a result of History. Thermodynamics was originally developed by physical scientists and engineers. They were concerned with making machines (steam engines) for the industrial revolution. Steam engines are heat engines. That is they thought in terms of input (heat in the form of fuel) and output (work). Both of these were thought of as 'naturally being' positive quantities. So they wrote their version of the Law of Conservation of Energy (The First Law of Thermodynamics) as ΔU = q - w. Chemists came to the scene from a different point of view. They wanted all forms of energy to have the same sign, whichever side of the conservation appearance they appeared so they could present the equation as a sum on both sides of the equation. So they wrote their equation as ΔU = q + w. By then it was also realised that, although all the terms are energies, there is a difference between ΔU , which is a state variable of the system, and q and w which are exchange variables of the energies crossing the system boundary. So they tidied up by stating that all energies crossing the boundary from the system to the surroundings are negative and all energies passing from the surroundings to the system are positive. Now they could add them up, move them about in equations and between equations in other parts of Science in a consistent manner. It is an improved system But it shows the importance of knowing the sign convention in use and the equations that go with it. This last remark also applies to other such instances of multiple conventions such as those in Electricity, Elasticity and elsewhere.
3. 4 points

## IQ rates are dropping in many developed countries

Citation needed. Maybe it is just compensation for the Flynn effect. I would guess the lack of a good definition of IQ and the corresponding arbitrariness of the tests accounts for a large part of it. Maybe modern communication technology and social media means that cultural change is happening faster and the tests can no longer be fudged quickly enough to compensate.
4. 3 points

## Small to Large? [Split from What determined the inital state of the universe?]

Why is it apparent that small things determine how big things work and not vice versa? Why is cause and effect noncommutative with respect to "size". In the sense that CAUSE is due to some physical laws: Quantum fluctuations CAUSE real and virtual particles. Real particles cause leptons, quarks, bosons. Leptons and quarks cause protons, neutrons and electrons. Protons neutrons electrons cause hydrogen helium and carbon atoms. Hydrogen, iron and oxygen cause stars, planets, and water. Stars, planets and water cause galaxies, solar systems, and oceans. Galaxies do not cause stars. Stars do not cause hydrogen. Hydrogen does not cause protons. Protons do not cause quarks. Quarks do not cause real particles. Real particles do not cause quantum fluctuations. The direction of time is forwards? The direction of cause is bigwards?
5. 3 points

## Newton's third law pair

What makes you think that? Was it a hanging slinky that was dropped?
6. 3 points

## ESO images a planet forming around a star

This is awesome. A picture of the dust cloud around a star 520 light years away. But better than that, there are signs that a planet is forming. Full story here: https://www.eso.org/public/news/eso2008/ Note that this is a real image, not a simulation or "artists impression"
7. 3 points

## Paper: A causal mechanism for gravity

Because - as I have attempted to explain - time dilation is a relationship between distant clocks, whereas a field assigns a particular object (a tensor of spinor of any rank) to each local event in spacetime. You cannot point to an event in spacetime and say “I am going to assign time dilation factor X to this event”, without any further qualification - this does not make any physical sense. The most fundamental entity in GR (and the solution to the Einstein field equations) is the metric tensor field - it assigns a metric tensor to each event in spacetime. To put it in the simplest possible terms, the metric tensor field allows you to quantify how each event in spacetime is related to all other events - both in spatial terms, and in terms of time. It does so by defining a mathematically precise relationship between neighbouring events, so that, by integrating along curves, you can calculate relationships between more distant events, e.g. the length of a world line connecting them. Time dilation in GR is a geometric property of world lines, in that it is the ratio between the lengths of world lines between the same events - the total time a clock accumulates between two given events is equivalent to the geometric length of the world line traced out by that clock. And how long that world line will be depends on the geometry of the spacetime it is in, and what kind of world line it is. Take for example a rotating spherical body, such as a planet. If you let a test clock orbit the planet once in its direction of rotation, starting and finishing at some point P, then that orbit will take a total time T1. If you now start at the same spot P, but orbit in the opposite direction (counter the planet’s direction of rotation, but along the same orbit, with all other initial and boundary conditions remaining equal), you will get some orbital time T2, which will be ever so slightly different. That’s because, even though you start at the same point P, and traverse the same spatial distance along the same orbit, the geometry of spacetime is such that the lengths of the two world lines will differ. The ratio between these two geometric lengths is one example of gravitational time dilation - the value of that ratio depends on where the point P is, the initial and boundary conditions of the clock kinematics, and the global geometry of the underlying spacetime. How would you capture all this by assigning a single value to point P, as you seem to want to do with your “time dilation field” idea? Again, on closer consideration, in order to capture all relevant degrees of freedom so that all aspects of gravity can be correctly modelled, independently of the precise circumstances, at least a rank-2 tensor field is necessary. That’s what GR does.
8. 3 points

There is a lot of false information there. -Without testing you do not know what you had. Making medical assumption based on gut feeling is really bad idea. -Influenza is not 100% symptomatic. Estimates are difficult (for obvious reasons). Longitudinal tests based on serological studies tend to estimate above 75% of asymptomatic cases (e.g. Hayward et al. Lancet 2014) . Note that influenza is much better investigated than COVID-19 and there are still a lot of unknowns and with influenza there are widely divergent estimates. The only thing we know with certainty is that your assertion is entirely unfounded. - Asserting that your feeling trumps actual data via testing is utterly ridiculous. Of course MDs should order tests. One might call it evidence-based medicine or just common sense. Acting on anything else is basically endangering oneself and others. - The unknown regarding immunity is actually correct. We only have limited data suggesting that there may be immunity, but we need to collect more. Also serological testing (but not, say gut feeling) can provide additional evidence of duration of immunity.
9. 3 points

## HEAR MY PLEA

A dream is nothing more, than a sea filled with life, full with the broken hearts of those before, experiencing pain and strife, wishing upon a star of light in which send theirhearts a soar, upon their gaze and flying wings, they jump in the sky searching for something more, in their flight they see the lands in which they never knew, and on catching the light in which they had dreamed, they discover something new, That the world in which they once inhabit was nothing but a dream, and that the knowledge in which they had captured is not quite exactly what it seemed, they had not flown into the sky, but through a looking glass. And upon reaching the end they realize something finally at last, They had not been flying but simply seeing through their own eyes, peering through a telescope, viewing their own demise. And upon viewing of the world they see others fall, those who are all still looking to the sky, hoping to hear the sirens call. So it is the dream in which I hope, to escape this land of mine, to understand the stars above, before running out of time, to finally touch the edge of the universe, before it is to late, to inspire those who dream of the impossible as well, before the world is consumed with hate, p.s. not sure how you wanted me to respond so I wrote my own poem! p.p.s. not good at poem structure soooo it might be a little bad. I do not know If this is guided towards me or not, but I don't know, build a boat I guess. Power only exists for those who believe in power, I just wanna make cool things and fly around because its fun!
10. 3 points

## Is there a value or something else that indicates the orientation of an orbit?

There are a number of elements that are used to fully describe a planet's orbit.: The semi-major axis of the orbit (average orbital radius) The eccentricity ( how elliptical the orbit is) The orbital inclination The longitude of perihelion The longitude of the ascending node. The last three are measured with respect to the Earth's orbit around the Sun. The imaginary plane which passes through the Earth's orbit is the ecliptic. The orbital inclination is how much the planet's orbit is tilted relative to this plane.* The longitude of perihelion is measured relative to the Vernal equinox. (draw a line from the Sun that passes through the Earth's orbit where the Earth would be on the date of the spring equinox.) If you draw a line between planet and Sun when the planet is at perihelion ( the closest point of its orbit around the Sun, the angle between this line and the line above will give you the longitude of perhelion. (which also gives you how the major axis of the orbit is aligned). The longitude of the ascending node gives you where the plane of the planet's orbit and the ecliptic cross each other. *Because the Earth is subject to various gravitational disturbance from other planets, this plane can change. To keep things simple, the ecliptic is defined as the plane of the Earth orbit on the starting date of the epoch we are presently in. That way, we aren't always adjusting the inclinations of the other orbits due to the Earth own orbital changes.) All of these elements are subject to change over time due to being perturbed by other bodies in the solar system. The Horizons web site can give the these values and the position of a planet for any date: https://ssd.jpl.nasa.gov/horizons.cgi#top
11. 3 points

## Is there a value or something else that indicates the orientation of an orbit?

Here is an example of a elliptical orbit where we can see the other focus more clearly than your drawings: (From: https://www.schoolsobservatory.org/learn/astro/esm/orbits/orb_ell) If we take the line between the Sun and the other focus, I think you are asking: "what is the angle of that line?" (Here it is aligned with the X-axis, but it could be rotated at any angle) Is that correct? If there is only a single planet (as in that diagram) then it doesn't really matter what orientation you choose because there is nothing to compare it to. If you have several planets, then their ellipses will all be aligned differently. The only way you can know the actual alignments is by making measurements of the planetary orbits. Here is a more realistic diagram of several orbits in the solar system: From: https://courses.lumenlearning.com/astronomy/chapter/orbits-in-the-solar-system/ - that looks like a good page that might answer a lot of your questions. As you can see, the planetary orbits are pretty close to circular. Also, the relative alignment of the ellipses will change over time as the interaction of the bodies will cause the orbits to deviate from perfect ellipses. Like this: From: https://en.wikipedia.org/wiki/Apsidal_precession Note that if you are simulating the orbits by calculating the positions after shot time intervals, you need to be sure your simulation converges. For example, if your time steps are too large, then the simulation will be inaccurate and the orbit will become unstable and you will fling the Earth off into space. Not easy, because the eccentricity the orbit is so small.
12. 3 points

13. 3 points

## GPE Required to Lift Object?

In the equation, r is measured from the center of the Earth. It seems that you just plugged 424 in for r. The answer you got would have been the GPE for the spaceship if it were sitting on the surface of a world with the mass of the Earth, and just 424 m in radius. For one, you have to convert km to meters, and for the other, you are looking for the difference in GPE between sitting at the surface of the Earth and being 424 km above it, not just the GPE for some point.
14. 3 points

## The relative worth of scientifc hypotheses and discoveries

Why does scientific inquiry have to have a quantifiable benefit to society, beyond the new knowledge itself? A benefit that you can't know until you've made the discovery? To quote from The West Wing Senator Enlow: If we could only say what benefit this thing has. No one's been able to do that... Professor Milgate:That's because great achievement has no road map. Well, the X-ray's pretty good. So is penicillin. Neither were discovered with a practical objective in mind. I mean, when the electron was discovered in 1897, it was useless. Now we have an entire world run by electronics. Haydn and Mozart never studied the classics. They couldn't - they invented them.
15. 3 points

## Are most climate scientists alarmists?

I understand how you can say that. But it's not that clear to me. First, dinosaurs, like any other megafauna, are almost anecdotal in terms of primary production, carbon cycle, etc. To give you an example, there are about ten trillion tons of methane stored in the oceanic bottoms that can't get out thanks to methane-metabolizing microscopic archaeas that are keeping it at bay. And, mind you, methane is 25 times more greenhouse-effect inducing than CO2 is. If you want to understand ecosystems you must look at microorganisms. They don't look as pretty in a theme park, but are far more important for the global chemistry. Another question is the rate at which this is happening. Back in the time of the dinosaurs the conditions were quite stable, and many big animals (quite a big bunch of them in terms of animal biomass) may have been slow-metabolism. As to the dinosaurs, we don't really know if they were or how many there were. We do know that all the plants were C3, because C4 plants did not exist. How did that affect the carbon cycle? Be aware, e.g. that RubisCO, the carbon-fixating molecule, is the most abundant organic molecule on Earth by far. In fact, C4 plants, which are more efficient at sucking up CO2 from the atmosphere, precisely evolved to adapt to the new, slowly-changing, low-CO2 atmospheric conditions. And that's the observation that leads me back to the question of rate. Organisms need time to adapt, measured in tens of millions of years, not decades, for those paradises that you picture in your mind to establish themselves. We are now pumping into the atmosphere an estimated billion tons of CO2 per year. The Earth is 100 years within a Milankovitch cycle of glaciation, and yet the glaciers are clearly melting, and fast. We are really fortunate that the Himalayas are still pushing up, because this geological process sucks CO2 from the atmosphere at an incredible rate, and sends it back to the sea. The really big question now is what will happen when the ice sheet on Greenland sloshes down to the North Atlantic, as it is sure that the salinity will go down significantly and the conveyor belt that equilibrates the water temperature will eventually stop. It is estimated that that will happen by 100 years' time. Have you thought in any depth about these and other factors?
16. 3 points

## Locusts for Lunch

As long as they are not eaten raw you are good to go, being a natural born hillbilly anything that moves slow enough to catch is potentially on the menu... Swamp rabbit was always my fav! I have large nets I use to catch grasshoppers for fish food...
17. 2 points

## Apologies and Grievances

I have never seen any reason for an apology from any of your posts. In point of detail I recognize your skill as a check to ensure I am accurate in my responses to other forum members and fully welcome any corrections or instances where clarification is needed. You need not worry if you find yourself at odds with any of my posts. This is a discussion forum and all viable opinions are welcome. Ps to all the kudos from yourself and others I am thankful. I am also positive you have knowledge of certain physics disciplines that exceed my own or Markus. The field of physics is a huge topic in applications.
18. 2 points

## Apologies and Grievances

I know Markus from another forum we belonged to before this one. And I've gotten to know Mordred fairly well. Both are extremely professional in the way they pass on knowledge without judgement. I have learned a lot from both, and hope to learn much more. Neither seems to participate much in forums like Politics, Religion, Ethics, etc., where opinions matter a lot, and tempers can flare; although it would be nice to hear their opinions on some matters. I don't think you need to worry about either of them getting 'pi*sed-off'. Watch out for that Zapatos guy though, He's American, and has guns .
19. 2 points

## What is the meaning behind multiplication in physics?

Hello. Not sure I understand your question but here is an attempt, also using geometry. I'll try to include your note regarding the sum v+v+v... If you have a constant velocity v and plot a graph you could think of the distance s as the area under graph. A numerical example: So to calculate the distance we could use multiplication 5*10=50 in this case (5 seconds of 10m/s velocity) or we could just use sum 10+10+10+10+10=50. Numerical result is the same. But I think the physical result is different. Le's take a to take a look at the units. Velocity is m/s and time is in seconds. If we just add velocities 10+10+... We have, physically, an increase in speed from 10 m/s to 50 m/s. So for the sum to physically get the correct result, the distance, we need to include the multiplications: 10*1 + 10*1 +...=50. Or with units spelled out: 10 m/s *1s + 10 m/s *1s +...=50m. Side note: When stating v+v+v+v... maybe you are looking for https://en.wikipedia.org/wiki/Integral ?
20. 2 points

## What is the meaning behind multiplication in physics?

Multiplication is a term with a very wide scope in both Mathematics and Physics, where it means (in both) Multiplication is a binary operation combining two mathematical objects or physical entities to produce a defined result according to stated rules. Binary means there are two participating objects or entities. That wide meaning gives rise to a whole host of uses or interpretations since it depends upon the objects or entities and the rules of combination and in some cases the order in which the operation(s) are carried out. In Mathematics we would expect the result of the multiplication to be another mathematical object In Physics we would expect the result to be another physical entity. The nature of the physical entity give rise to both the meaning and motiviation. But In Physics it is possible to have more than one result. For instance Force x Distance can result in a moment or energy, which are different physical entities. Does this help?
21. 2 points

## PAPER: A Fluid Model of Matter

@william1952 In the meantime, here is a paper that could be a starting point for further reading: "On the dimensionality of spacetime". https://space.mit.edu/home/tegmark/dimensions.pdf The paper explains how there are issues with any idea that requires another number of dimensions than 3+1. The paper also provides references for further reading.
22. 2 points

## Trump Responsible for Some US Deaths?

President Trump's strategy is simple ... He ran on a platform of 'draining the swamp'. He's fired four IGs in quick succession; the latest for investigating Pompeo's misuse of resources. I guess without IG overseers ( or free press ), he can claim there is no swamp. Similarly, since infections were found in White House staff, everyone there is tested daily; The rest of the country is way undertested. I guess without testing, he can also claim there is no more virus. What bothers me is his supporters, who defend him and buy into his crap. Abuse and overreach of power, nepotism, pay to play, bribery, corruption, and the worst response to the pandemic of any civilized country, and he still has that kind of support ( people thinking he's doing a god job ) ?
23. 2 points

So if I publish a paper on Invisible Pink Unicorns in my back garden, and no one responds to it, then that means my unicorns must be real? What a ridiculous argument.
24. 2 points

## Aliens

Now if only these drones could insinuate themselves into some kind of distribution chain so they could get humans to actually BUY them and have them delivered straight to their unwitting victims....
25. 2 points

## Aliens

I don't see how one follows on the other. Why would their respiratory requirements affect whether or not we think they exist in the first place? The real issue is more about complexity. The lifeforms we know of that "breathe" other elements (sulphur, hydrogen) are pretty simple organisms, and not the kind of species you'd expect to develop space travel. The more complex organisms we know of use oxygen in some way. Also, aliens don't need to be exactly like us in order to manipulate oxygen. Many creatures on Earth use oxygen in different ways to get what they need.
26. 2 points

## God and Science

I consider science and religion (the general concept, not any particular religion) to be different and distinct domains of enquiry, that ask different questions about the world and the human condition. As such, there is no reason why the two can’t coexist harmoniously, in fact it is natural for them to do so. Problems only arise when people start conflating the two - making religious claims about the empirical world, or conversely making “scientific” claims about what is not readily amenable to the scientific method, quickly leads to unnecessary disharmony and arguments (and potentially worse). You don’t use a torque wrench to hammer in a nail - one must pick the right tool for the job at hand. I think both science and religion are equally of value when it comes to understanding what it means to be born human, but they shouldn’t be conflated and confused, because they relate to different aspects of our experience.
27. 2 points

## Algebra

Why? Change doctor It is easy.. If you have decimal e.g. 1111 factors will be 101 and 11. If it is e.g. 111111 factors will be 1001 and 111. And so on. You just have to answer question if number of decimal ones is dividable and has factors by itself. 91 is not prime. It is dividable by 7 and 13. 1111111 1111111 1111111 1111111 1111111 1111111 1111111 1111111 1111111 1111111 1111111 1111111 1111111 is dividable by 1111111.
28. 2 points

## Question about axis of rotation and center of gravity

Yes you are seriously mistaken. Just think of a solid heavy weight swung round on a long string. The centre of rotation is the hand holding the other end of the string The centre of mass is somewhere inside the heavy weight. Just to be precise, "the centre of gravity is on the line through a body leading to the centre of the Earth, that the weight of that body appears to act." And the axis of rotation is determined mostly by external agencies. Might be better to phrase this The centre of gravity or centre of mass of a body may change if the configuration of the parts of the body changes. And the axis of rotation is determined mostly by external agencies.
29. 2 points

Polio is an RNA virus; more than one vaccine has been developed for it.
30. 2 points

## Matter/anti-matter asymettry, Dark matter, dark energy and how they relate

Two very important concepts you don't seem to grasp. The universe, in the Big Bang model, evolves from a smaller version of itself, where separation between non-gravitationally bound objects decreases, as you go further backwards in time. The logical end result of this backward trip in time, is a singularity, but there are many reasons to discount the singular universal beginning, so we conjecture a hot dense initial state. Once expansion ( and/or inflation ) starts, we have an era that is dominated by radiation, as electrons cannot sick to protons to form atoms. The ambient 'energy' ( temperature ) is like in the Sun, a plasma, and only when the temperature drops below 3000 deg C , will electrons bond to protons without ionizing. If we consider this temperature, and factor in the approximate expansion of the universe since the end of the radiation era ( slightly more than 1000 times, we get the temperature of the CMB ( I believe G Gamow first did this calculation in the 40s ) of 2.7 deg C. And sure enough, Penzias and Wilson found the CMB in the 50s, at just that temperature. You cannot be 'outside' the universe. Saying that 'if you cannot visualize it it doesn't exist', is a cop-out for that reason. Where is the center of a doughnut shape, if you are INSIDE ? And since anytime you are looking into a distance, you are in effect, looking back in time ( finite speed of light ), it makes no sense to consider only 3dimensional volumes. You need to consider 4dimensional space-time. Can you visualize that ??? Both of these concepts also explain why the CMB has not passed by you. The CMB is the relic radiation of EVERY POINT in the universe, not a specific location, so it can never pass you by on its way to somewhere else. One final point... You ask us to discuss your conjecture based solely on 'logic' ( not mathematically defined logic, but personal subjective 'logic' ), yet you demonstrate that you lack the basic knowledge of even some of the things you are trying to explain, such as Dark Matter. ( I would hate to hear what your take on Dark Energy is ) You are basically asking people to waste their time discussing your conjecture, as all indications are that any mathematical model will be similarly flawed. You wan't to build a skyscraper, yet you lack the foundations to build it on; why not ask questions where you lack knowledge, and build a foundation. Then you'll have some idea as to what kind of building you can build on those foundations
31. 2 points

32. 2 points

## Aren't some science documentaries ever so slightly sensationalist?

Ok. I really must take issue with this, because although I do find some points of agreement with you, like, e.g., the "it would defeat the purpose" argument, or the general intention to reach wider audiences that these shows blatantly target, I really think you're flushing too much down the plughole there. As to school teachers pictured as "exiles,' I really must tell you that I've found sour exiles and leeches at university and school alike. Some of the best were at uni, and some of the worst too. I know enough of science to know that there exist vast graveyards of good-for-nothing sloppy science made by professionals, like some 'glorious' pieces of GR that were just plain wrong because the authors didn't know they were dealing with tensor densities, and messed up the calculations. They're still there, published, 80-odd years afterwards, to the shame of all. It is by no means the rule, thanks to the peer review system, but it just happens to happen. Same goes for papers that are but leading-nowhere speculations dressed with the glories of mind-numbing formalism. Again, not the norm, but there is such a thing as bad professional science and there is such a thing as good popular science. It's not as simple as researchers or university professors = people in the know, versus school teachers or popular science writers = poor idiots who don't know what they're talking about.
33. 2 points

## U.S. Democratic Primary

Enough is enough. I'm not sending INow any more photos.
34. 2 points

## Gravity-driven transpotation along a shallow incline

Relying on friction probably isn't good enough to ensure a safe and controlled speed of descent. You have to take the cart back up to the top, which would require a source of energy. Also, there is probably limited number of people who only ever want to go downhill so, at some point, you are going to have get the people back up to the top as well. Now, here's an Idea: why not have two of your carts tied to each other with a cable that goes round a pulley at the top of the hill. The cable is just long enough that when one cart is at the top, the other one is at the bottom, When you have passengers in both carts, you let the one at the top go down and pull the other one up. You may need to use some power to overcome different loads and control the speed, but less than without the counterbalancing cart. https://en.wikipedia.org/wiki/Funicular
35. 2 points

## Applied physics: range of HD antennas.

Surely this belongs in the enginnering section, you even asked for an electrical engineer. It is not rocket science after all. However asking for an engineer is a good idea since there is much engineering commonsense and experience involved. 'Line of sight' is funny thing because it begs the question "who can see what ?" Height is important, but not all important. It depends what is in the way. You can (sometimes) achieve the same result moving two feet to the right or left to avoid a nearby chimney stack as 20 feet or more vertical elevation to look over the top of it. I agree with the underlined words of this extract from StringJunky's link But Amazon as a first class engineering supplier ?? The linked site seems only to shop at old smiley. Some advice if you are doing this yourself. Only a vey small part of the antenna is actually the receiving or pickup device. Most of the antenna is either focusing/directing/filtering metalwork. So dimensional and alignment accuracy and stability are vital in assembly. (Most DTV antenna come as self assembly flat packs). Small errors of twisted or displaced parts can ruin the performance of the best antenna. To answer your two questions directly, The range depends mostly upon the height of the transmitter, not the receiver. Which is why these are placed on mountains where possible. And yes if the transmitter can place a signal 200 miles away, that signal can be received. As an example, my antenna is about 75 miles form the Bristol Transmitter, which is placed on top of the Mendip range of hills. It is installed in my attic (roofspace) simply hanging by two cords. I get a better signal inside the roof than on top of it because of nearby chimneys. I get almost zero signal at ground and first floor level, even in the trees in the garden away from the house. The antenna picks up a better signal from the Mendip transmitter than the nearer Blackdown Hills transmitter, which is only 20 miles away.
36. 2 points

## IQ rates are dropping in many developed countries

It would be "aren't" because we require grammatical agreement. In the same that we say "you are" and not "you is" even when talking to a single person because "you" is a plural pronoun (we lost the singular form, "ye", a long time ago although it is still used in some dialects).
37. 2 points

38. 2 points

## Is gravity , absolute space ?

Umm, a singularity is non-sensical, it is the point where mathematical models diverge to infinities. And they have no dimensions, making 'within a singularity' even more non-sensical. People would take you more seriously, if you knew the difference between a singularity and a horizon. ( not that it makes a difference to the rest of the word salad ) You should learn some !
39. 2 points

## Covid: Disinfect Money

Hi everyone ! In shops, one remaining Covid contamination path is money. An answer is to allege that money doesn't host the virus, I read that. Or we can try to tackle the problem. UV light is known to destroy virusses, including Sars-Cov2. UV LED are available for near-ultraviolet Hg wavelengths, compact, reliable, efficient. This could irradiate the money between the cashier's and the customer's hands, in both directions. The rest is mechanical design, still imprecise. The apparatus must stop the UV from exiting but irradiate both sides of banknotes and coins. Both users could introduce the money at the top, say between a pair motorised soft rolls, and grasp it at the bottom, after an other pair of rolls. UV between the pairs of rolls would be blocked by the rolls. Nice for banknotes, but the coins would fall at once. It also needs a soft material that survives UV. This shape has the smallest footprint. Or a platter would tun slowly. The customer has a sector to introduce and extract money, the cashier has an other sector, and the two sectors in between irradiate the money under a cover. Silica and variants make the platter transparent to UV. Maybe banknotes and coins should have different paths. Possibly the soft rolls for banknotes and the platter for coins. The apparatus must be easy to open, and opening must halt the UV emission. Fluorescent surroundings would reveal any UV leak. Marc Schaefer, aka Enthalpy
40. 2 points

## IQ rates are dropping in many developed countries

Some thoughts,frequently speculative, in no special order, on the thread OP and some of the points made by other members: The OP contains the inherent assumption that IQ has a strong correlation with "success" of the individual and of society. I think it is generally understood that "success" is much more complex than that. Thus Nelson Mandela was undoutedly of above average intelligence, but it was his grit, determination and compassion that enabled his achievements. That raises the question, why would a decline in IQ (unless it were off a precipice) be of much concern? I would be more troubled by a fall in commitment and caring. I suspect that declining average IQ is unlikely to have a major impact on the value of the outliers. There should still be Newtons and Einsteins and lesser luminaries to do the heavy mental lifting for society. Most of us are drones compared with the 'top level thinkers'. The development of AI is likely to eliminate a large scale need for those with above above average IQs but that fall short of genius level. The increasing reliance on AI over the next century may be the real challenge we face in relation to societal intelligence. I keep getting flashes of the Eloi and Morlock of H.G. Wells' Time Machine, in which the decadent and now dumb elite are preyed upon by the subterranean worker Morlocks. (The novel was, at its heart, about the nature of society and its possible trajectory. The SF element was a device to enable that exploration.) I have long thought the main value of the IQ test was to determine how people would do on an IQ test. I benefited from a University education funded by the government, fees paid and sufficient money to live on, so that aspect (for undergraduates) of Moreno's proposals resonates positively with me. However, that was at a time when university education was, in the UK, for 5% of the population, not closer to 45%. I hope that this expansion of student population has not been achieved at the expense of standards, but I remain nervous on that point. Of all the points raised in the thread so far the drop in attention span is the one I find most concerning. Intelligence is only of value when it is employed effectively. That takes time and practice and application. In other words, it requires one's attention be focused on a problem until it is solved. On an upbeat note, perhaps we are developing aspects of intelligence that are appropriate to the environment we are now living in and that are not well discerned by the current tests.
41. 2 points

## Coronavirus: Theresa May criticises world pandemic response

It is quite common for "retired" politicians to become much more statesman like in their words and actions. Freed of the need for political machinations they can speak more from the heart (something I thought May did not have). Taking a leaf from the fight against the virus, I wonder if we could take plasma from such politicians and inject it into the present incumbents, hoping that the antibodies would deal with the hypocrisy and kant flowing in their veins.
42. 2 points

## The end of modern civilization is near?

Angela "opened borders" to help southern European countries to solve problem of illegal immigration, taking part of the ones that arrived to Italy and Greece and other countries. It was movement of solidarity with involved European countries. Flood of migrants, who don't know language, don't have work, don't have money, can disrupt any country, and nationalists or other populist parties can win the next election, promising people fight with immigrants, which won't do any good.. The situation of refugees is even worse in the Middle East. For example Jordan has 10.4 million citizens and 1.3 million refugees from Syria.
43. 2 points

## The world has changed...

'Imagine there's no heaven It's easy if you try No hell below us Above us only sky Imagine all the people Living for today. Imagine there's no countries It isn't hard to do Nothing to kill or die for And no religion, too Imagine all the people Living life in peace. Imagine no possessions I wonder if you can No need for greed or hunger A brotherhood of man Imagine all the people Sharing all the world. You may say I'm a dreamer But I'm not the only one I hope someday you'll join us And the world will live as one." John Lennon 1971 Imagining is easy. Realization is the hard part.
44. 2 points

## Trump Connection to Hydroxychloroquine (split from Corona virus general questions mega thread)

You should watch them. The rise they cause in blood pressure and vigorous exercise, thumping the wall with ones fists and kicking the furniture to pieces, obviate the need for regular exercise.
45. 2 points

## Compactification [Split from Have we found enough puzzle pieces to get a big picture]

There is no difference between the mathematician's definition of 'compact' and the physicist's. Indeed this is explicitly stated at the beginning of your link. note the sentence which begins "the methods of compactification are various....." Here you are talking about compactifying a group. Nothing wrong with that , not all sets are groups though mathematically the meaning is the same. But mathematically 'compact' and 'compactification' is about sets. We like compact because it allows us to use general theorems like the Heine-Borel theorem as justification for the mathematics of our functions and operations on them eg calculus. We like compact surfaces and manifolds as they keep sets and their coverings under control. The same ideas are also used by Engineers, as this extract from "Introduction to Differential Geometry for Engineers by Doolin and Martin" shows. Note their comment about research papers!
46. 2 points

## Have we found enough puzzle pieces to get a big picture.

Let's put this into perspective. You want someone to do the math for you. Ok so would you understand the statement. The first property in the definition of a Calabi-Yau manifold. X is compact if every collection of sets $V_j\in\tau$ which covers X ie $X=U_jV_j$ which has a finite subcover. If the index j runs over finitely many sets then this condition is met. If j runs over infinitely many sets. This would require that there exists a finite subcollection of sets... This is an example of compactification for the topological spaces used in Calabi-Yau manifolds. Source being String Theory on Calabi-Yau manifolds by Brian R Green. Can possibly understand that statement without understanding differential geometry and holonomies of topological spaces ? https://en.m.wikipedia.org/wiki/Topological_space https://en.m.wikipedia.org/wiki/Hausdorff_space https://en.m.wikipedia.org/wiki/Holonomy https://en.m.wikipedia.org/wiki/Parameter_space https://en.m.wikipedia.org/wiki/Configuration_space_(mathematics) https://en.m.wikipedia.org/wiki/Phase_space The following links above all involved in the example I gave.
47. 2 points

## An Alternative Equation for the Wavefunction and its Eigenfunctions

For the OP this is just a primer to help understand the basics of QFT and how force is applied. Keep in mind this is a workup I did on this forum a few years back but it saves a lot of latex. You should be able to get the gist of how QFT differentiates from QM. One difference to recognize and I didn't cover is that the Schrodinger equation is first order while the Klien Gordon is second order. (This is a conflict of QFT to QM that requires a seperate fix). The repair comes into play when you factor in particle number density... Just in case your not familiar with time derivatives (the overdots) https://en.m.wikipedia.org/wiki/Time_derivative This paper is rather advance but it will give you a good idea of how the Langrangian is used to describe the standard model. https://www-d0.fnal.gov/results/publications_talks/thesis/nguyen/thesis.pdf It should give you a good idea of what you are up against...
48. 2 points

## Corona virus general questions mega thread

I think the need was never in question (as well as for the other treatments). Due to the ongoing situation, often the designs are less than optimal and/or part of emergency/mercy treatments. I have a hard time imagining how it would work. Most of the viral particles are not just sitting on tissue, but are inside the cells (or after leaving cells would circulate). I would assume radiation that is damaging to them, would also be harmful (probably more so) to live tissue. After exiting they also disseminate via body fluids so point sterilization does not seem to be the right strategy to me.
49. 2 points

## Build you own Quantum Computer - 36C3

! Moderator Note OK then. Until you can present this in written form, it can't be discussed meaningfully here. Reviewing videos is NOT what we're interested in here. There are other places though, and we wish you the best of luck. Again, come back when you have your questions available for written discussion. Thanks for understanding.
50. 2 points

## Trump Connection to Hydroxychloroquine (split from Corona virus general questions mega thread)

He might just be promoting one of his investments:
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