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  1. Dear All, I am going to take a hiatus from the forum from today. As some of you might know, the natural sciences are not my only area of interest; in particular, I am committed to a form of spiritual practice as well, and have been living in a Buddhist monastery as a lay person for the past few years. I have made the decision to deepen this practice further by ordaining as a monk in the Theravadin Thai Forest tradition, and for various logistical and monastic-political reasons this should ideally happen at a traditional training monastery in Thailand. So tomorrow I will be departing for Thailand to seek ordination there. I think it doesn’t need pointing out that forest monks generally don’t spend a lot of time on Internet forums, so chances are that I will only get to check in here very occasionally, if at all. That being said, there are a lot of question marks and uncertainties, particular in terms of immigration formalities, so it is possible that I need to come back here to Europe in a few weeks once my initial entry permit runs out, and make alternative arrangements from here (meaning I’ll have to find another place to ordain). I will only know once I get to the monastery and start dealing with the local immigration authorities (I see frustration and nightmares on the horizon!), but I’m willing to take that risk. I have been debating whether it is useful to present my reasons for going this path - you have seen me here being on about physics and equations all the time, so this might appear strange to some of you. But I’ve decided not to, because when it comes down to it, I can’t really present a convincing rational argument - this decision simply didn’t come about as the result of reason. I will say only that I’ve seen and understood enough in the spiritual practice that I have already done in the last few years, to know that this is the right path for me. The argument is a phenomenological one, not the result of rationality, so it cannot be easily conveyed in a written post. Spirituality ultimately expresses itself in the kind of person you become by engaging in it, and that’s not something you can fake or wear as a mask. You also cannot reason yourself into the monastic life - that is far too weak a basis for anyone to be at peace with that form of life, never even mind to be able to derive any benefit from it. It needs to be a true conviction that arises somewhere deep within, and that cannot be verbally communicated to others. I will add here that for me there has never been any contradiction between scientific endeavours, spiritual practice, and philosophical enquiry. Not only is there no contradiction, for me these are just aspects of the same underlying motivation to better understand the human condition; hence, if engaged with in the right way, they are complementary and inform each other. I have always felt strongly that it is necessary to achieve some kind of synthesis of these three things for us as a species to make any kind of real long-term progress, since each one in isolation can be misused for harmful and even destructive purposes, as history has sadly shown us all too often. So anyway, thank you everyone for sharing in these discussions, and I hope I have been able to make some kind of contribution - no matter how small - to this forum. In case I’m not back here for a while, I wish all of you the very best, and hopefully we’ll cross paths again. Keep my account open, just in case
    12 points
  2. I got a major award today (plaque, not a sexy leg-lamp) for my "staunch defense of USNO's interests" in a project I'm working on
    8 points
  3. I was reading through Mordred's long standing thread on space and I came across some posts from Mike in the early part. Members may wish to know that Mike passed away earlier this month after a long standing degenerative illness (not covid). Mike was an interesting character, an artist with a degree in Physics and the founder of a successful manufacturing business before retirement to Cornwall. His artistic (dreamy) side gave him an unusual and sometimes frustrating perspective on Physics, especially later in life when we knew him. But he was a genuine character and sometimes offered suprising insights as well.
    8 points
  4. Staff have decided to update the forum rules to include the following: This is in response to a number of threads and certain members who have made threads here under the premise of 'just asking a question,' only to reveal that they are in fact trying to peddle conspiratorial or otherwise nonsense ideas. While covered to some extent by pre-existing rules, we have decided to make it explicit that we will not be hosting these sorts of threads, if for no other reason than the fact that they are a waste of everyone's time.
    8 points
  5. OK let's clarify something here. First consider the following definitions. Mass is resistance to inertia change Energy the ability to perform work. Spacetime a geometric model system with 3 spatial dimensions with 1 time dimension. In physics dimension is an independent variable or value that can change without affecting any other mathematical object. So how does mass curve spacetime. Well GR models bodies in free fall that is without any force applied. Time is given units of length and can be called an interval. This is done by setting c which is constant to all observers and adding a unit of time. So the time coordinate is given units of length by ct. [latex] (t,x,y,z)=(ct,x,y,z)=(x^1,x^2x^3x,x^4)[/latex] the last is in four momentum form for convenience as its useful to model a particle trajectory along the x axis. Now what is spacetime curvature. Well space is just volume... (Very important ) it isn't a stretchable bendable fabric... Those are just analogy descriptive. What spacetime truly means by curvature is the worldline paths for light it us the null geodesic. If you shoot two laser beams in flat spacetime those beams stay parallel. If spacetime is curved then the beams converge for positive curvature and spread apart for negative curvature. This is a consequence of how the mass term affects the time it takes for a particle to go from emitter to observer. That whole resistance to inertia. So let's drop two objects toward a planet. You have the usual Centre of mass. As the objects free fall they do not stay parallel. They will converge upon one another as they approach the center of mass. That what is really meant by curvature the free fall paths are curved. Not the volume of space.
    8 points
  6. So looking at the image below, it appears that Galagidae have recognizable soles, but Cynocephalidae do not : and when we look at a primate phylogeny, we see the split between these two groups is around 65 million years ago: So soles originated about 65 million years ago, give or take. You meant soles as in soles of the feet, right?
    8 points
  7. So if I change the charge of one plate, somebody can measure an instantaneous change at the other plate. Wouldn't that be a violation of special relativity? @Menan You show that you do not understand entanglement. Let's go one step at a time. First a classical example. I have a bag of balls, they are all red or green. Without looking I pick two balls, and I put them in separate boxes. I keep one, and send the other far away. Then I open my box, and see it is a green ball. What can I conclude about the colour of the ball in the remote box? Right, nothing. And why? Because there was nothing special with my picks. It could have been two reds, two greens, or one red and green. Now I pick, looking of course, one red and one green, and put them in two separate boxes. So what I did here is 'entangle' the balls. Now I shuffle the two boxes, so that I do not know which one is which. If I open one, and see that it is red, I immediately know that the ball in the other box is green. And of course, this is independent on the distance. If I send the second box lightyears away, and only then open my box, I still know immediately what some alien sees when he opens his box. I know it because the observations are correlated. And the correlation already happened at the moment of my picks. That is the moment of entanglement. It is not when the boxes are opened. Now in quantum physics, there are processes where two particles pop out, which have e.g in one aspect always opposite values. Say the direction of spin. So if I measure the spin e.g. in a vertical direction, say it is 'up', then I immediately know that the other one will measure spin 'down', when also measured in the vertical direction. But as with the balls, the 'moment of entanglement' is when these particles popped into existence. But in quantum physics a few things are different: first, it is impossible to say which particle has which spin without measuring (it is as if I created the green and red balls, including their boxes, without knowing which ball is in which box). But as the two particles are entangled, if I measure both, the measurements will always be correlated. And there is nothing special with correlation: if I send one particle far away, and then measure my particle in the vertical direction, and the alien measures his particle in the same direction, I will always know what he measures: the opposite of my measurement. The 'spooky' aspect comes in when we do not know from each other in which direction we measure the spin. It can be vertical, horizontal, 30o, 45o, 55.3977o. What we find is that the correlation is stronger than one would expect if we would assume that the particles already had a definite spin from the beginning. But it still is correlation, not causation. As with the red and green balls, there is no direct causal relationship between my and the alien's observation. The causal relationship goes back to the moment of 'entanglement'. Everything afterwards is just correlation, and therefore cannot be used to transfer information. And because there is no causal relationship between my measurement of the spin of my particle, and the alien's measurement, I cannot use entanglement for sending information. And all this is very well understood by all quantum physicists, and is no secret at all.
    8 points
  8. I suspect distaste for homosexuality is inborn in many of us. Given that we have a drive to be attracted to the opposite sex, we find the idea of sex with someone of the same sex a big turn-off. Consequently we may find the idea of a sexual approach from somebody of our own sex rather disturbing. If that is homophobia, then I am a homophobe. It seems to me that the blanket term "homophobia" is thrown around too easily. One needs to draw a distinction between personal sexual taste and the attempts by some to condemn different (minority) tastes in others. It is the latter that society should refrain from.
    7 points
  9. You can label it Political Correctness, or whatever you wish. The fact is that our Western societies are now almost at a point where the individual right nt to be offended, trumps society's right to free speech. And where your own personal, subjective reality can be forced, under threat of law, on the rest of society. If it was someone in authority doing this to society, you would all label him a despot, or dictator, or fascist. When it is anyone with a gripe against the rest of society, or a pretentious, virtue signalling university student, who has no clue what being underpriviliged really is, you guys all stand and cheer, while disparaging those who stand up against the nonsense, claiming they are out of their area of expertise, or just in it for popularity and money. You guys need to give your collective heads a shake !
    7 points
  10. Well, since Markus has expressed his desire to join a Monastery, I think that definitely answers the OP question. But, some words to Markus... ( no offence meant, just trying to lighten the mood ) A young monk arrives at the monastery. He is assigned to helping the other monks in copying the old laws of the church by hand. He notices, however, that all of the monks are copying from copies, not from the original manuscript. So, the new monk goes to the head monk to question this, pointing out that if someone made even a small error in the first copy, it would never be picked up! In fact, that error would be continued in all of the subsequent copies. The head monk, says, “You make a good point, my son.” He goes down into the dark caves underneath the monastery where the original manuscripts are held in a locked vault. Hours go by and nobody sees the head monk. The young monk gets worried and goes down to look for him. He sees him banging his head against the wall and wailing. “We missed the R! We missed the R! We missed the R!” “Father!” cries the young monk. “What’s wrong?” The head monk with tears in his eyes replies, “The word is CELEBRATE!"
    7 points
  11. I am unsure why you would think that - you have never upset me in the slightest with anything you have said, so no apology is necessary at all. But just to set the record straight anyway: it is highly unlikely that I know more about GR than you do I am merely an interested amateur, and everything I post here - without exception - is entirely self-taught. Unlike Mordred, I have no academic credentials in any area of science; truth be told, I never even went to university at all. My understanding of GR and physics in general is cobbled together from a variety of textbooks over the years. I am on the autism spectrum, and one of the defining characteristics of people on the spectrum is that we tend to get totally absorbed by narrow areas of interest (this is called monotropism) - for me that just happened to be physics, specifically GR, at least in the beginning; so I did a lot of reading and self-study in that area. In recent years my interests have diversified somewhat, and I also got involved with certain areas of philosophy and spirituality. Also, understanding GR is natural and intuitive to me, in a way that does not seem to be the case for most neurotypical people; perhaps people on the spectrum find it easier to step outside established paradigms (in this case Newtonian physics) and look at things from a different angle. We tend to have difficulties with other aspects of life, though. I can only speak for myself here. I have no interest whatsoever in anything to do with politics; I stay as far away from it as I can. Anytime in the past when I needed to get involved in politics (workplace, family, etc) it ended badly for me in some way or another. The main reason would be that, as being on the autism spectrum, I am unable to read social cues and guess at peoples’ social intentions. Social interactions between neurotypical people are a complete mystery to me, I cannot understand them. I function reasonably well in daily life, but that is only because I have learned to mask a lot; it’s not the same thing. To me, politics is a bunch of people with strong opinions, who do not recognise them as being opinions, and mistake them for some kind of reality. So they get terribly agitated when others don’t share them; there is a lot of suffering it it, really, and no one seems to even see that. I have plenty of views and opinions as well, but I tend to be able to recognise them as such (or so I hope), and see how they are changing with time, so I don’t try to push them on other people. They are just constructs of my mind, so ultimately they say more about my mind than they do about the world at large. As for religion and ethics, they are areas of interest to me - but I personally don’t see them as something to be debated or discussed on social media, which is why I don’t participate in those threads. Religion - or rather: spirituality - in particular is something you do, not just some passive view on the world. I see lots of people who call themselves “Christian” or “Muslim” or “Buddhist”, but these are just labels - those same people may speak and act in ways that reveal complete ignorance of the nature of human suffering. And conversely, some of those people I have met who were most at peace with themselves and the world did not label themselves in any way; they just lived a truth that existed within them on a visceral, intuitive level. So religion and spirituality are never external things, they come from the inside; they are lived, not debated. That’s all I can really share with regards to this. Ethics, to me, is the art of finding the path of least suffering, for myself and everyone else who is involved, in any given situation. There is no such thing as “right” or “wrong”, there is only cause and effect. One can write down general principles for this that may hold true in most cultural backgrounds, but ultimately it is again something intuitive and visceral, something that happens inside. Intention has a lot to do with it - if we act from a place that understands the suffering inherent in all sentient life, and consciously choose to act in ways that minimises it to the best of our limited abilities, then the seeds of our actions will generally be wholesome ones. Again, I think it has a lot to do with one’s reasons for being here. I am on this forum for two reasons only - to expand my own knowledge and understanding, and to help others do the same; and very often, these two things are mutually co-dependent, and happen simultaneously. It is no longer about getting anyone else to adopt my own views on things. Ultimately you cannot force someone to understand something; you can only offer them the tools that might enable them to put the causes and conditions in place for such understanding to arise eventually. But different people come from different backgrounds, and they are at different stages of their own journeys when they arrive here on this forum; it does happen that someone just isn’t ready to listen, and then it won’t matter what you say to them, regardless of how rational and scientific it is. They will be unable to see the merit in it. It’s not even their “fault” really, it’s just that the conditions are not right yet for understanding to arise. Getting upset or offended will never help in these situations - most often it is best to simply disengage and walk away. After all, it is their journey, so I don’t need to loose my own balance over it.
    7 points
  12. Just did not want to let this pass without a party (Dutch treat...). You are all invited at the lakeside! (Just Click on the picture to see it full size.) Thank you to all from who I learned a lot, and also thank you all who understand less than I do about certain subjects, but force me me to rethink, or make my viewpoint clearer, or force me to read some book or article (again). I noticed that much of what I read is influenced by topics here in these fora. And thanks to those who make this forum possible, moderators, administrators, sponsors, etc. Up for the next 1000!
    7 points
  13. 6 points
  14. Putin dies and goes to hell, but after a while, he is given a day off for good behavior. So he goes to Moscow, enters a bar, orders a drink, and asks the bartender: -Is Crimea ours? -Yes, it is. -And the Donbas? -Also ours. -And Kyiv? -We got that too. Satisfied, Putin drinks, and asks: -Thanks, how much do I owe you? -5 euros.
    6 points
  15. Despite a month of promises, on Thursday the 24th at night, conviniently while the Putin shitstorm started he reinstalled a prosecutor in the disciplinairy chamber who tormented a pregnant woman resulting in her death becuase of religious BS. The disiplinairy chamber is an illegal entity and a private tool of Kaczyński and Ziobro (minister of justice and prosecutor general in one person) and is the main reason which prevents us from receiving the 150 bln euro form the EU post Covid fund and results in us paying around 1mln euro in fines. Daily. The president is not autonomous, he's a tool and a clown, unfortunately. Just came back home from a day of trips, dropping people off at shelters and getting food and supplies.
    6 points
  16. There are several parallel issues here. One is that wealth acquired by the ultra wealthy tends to get put into tax shelters and nebulous investments so it grows (but remains outside the system), whereas that same money in the hands of the less fortunate goes IMMEDIATELY into the community around them. They spend it on groceries and vehicle repairs and school clothes for kids and paying the electricity bill so it’s not dark in their apartment anymore at night and their kids can read. The providers of those goods and services in that community where this money is being spent ALSO spend the money once received for THEIR groceries and THEIR service needs and on THEIR kids. Dollar for dollar / unit for unit… the money in the hands of the less fortunate does more net good than money in the hands of the already fortunate. Yes, spending from the wealthy also creates jobs and injects money back into the system, but very little relative to money used in “trickle up” stimulation packages. Also, a bit of extra money in the hands of someone who already has a bunch of it doesn’t tend to change their behavior or encourage extra spending. Getting $1,000 tax break when you’re sitting on $50M isn’t going to suddenly result in them finally making a call to a plumber or the purchasing a new dishwasher… but for the person living paycheck to paycheck that money literally changes lives, gets spent and injected back into the system quickly, and results in lasting reductions in poverty and suffering. When you’re living at the margins, every dollar counts. It also costs a lot to be poor. When the washing machine breaks, you can’t afford a new one but you can afford to pump quarters into the machine at the laundromat… but that ends up being more expensive on net. When the car breaks down, you don’t get to work on time and you get fired. The rich, however, have tax protected ways of growing their wealth and can afford tax attorneys to hide it. Paying more tax has more impact on their ego than on their lived experience. The anger at the rich is out of hand, though. We need better policies and enforcement mechanisms, not more hate and vitriol directed at those doing better than us. Sadly, the anger is probably in large part intentionally being amplified by the very people on the receiving end. If they can keep everyone mad and focused on the wrong things, then the status quo remains stable and no progress or change gets made. Like most issues in economics, we make a huge mistake by treating it as a moral failure when at its core it’s a policy failure. Fixing the policy is just super hard because the people with the power to change the laws tend to be the same ones benefiting the most from them… and also because focusing on wonky policy details is hard for a public who’s often just trying to survive through to tomorrow and who’d much prefer throwing stones and being distracted with us/them tribalism. Perhaps this thread could try focusing on wonky policy details instead of distractions like yachts and steel boats… or not.
    6 points
  17. Throughout the COVID-19 pandemic there have been key findings that have altered our understanding or required responses to this disease. For example, the realization that pre- or asymptomatic persons might be infectious has required a different approach to masking and social distancing. While we have several threads discussing the pandemic, I feel that recent developments justify a new topic, especially as it could be used to clarify potential misunderstandings. With the delta variant (B.1.617.2) gaining dominance we are seeing yet another change that requires us to re-think the trajectory of the pandemic. First of all, the transmission rate of this variant is much higher than estimates for the original strain. The CDC has compared it to chicken pox, which has a basic reproduction number (R0) of >10. What does it mean? First of all, this might indicate that vaccine-based herd immunity is entirely out of the picture. With a R0 of 10 you would need to have a total protection of >92% of the population. Since the effectiveness of the best vaccines against the delta variant are a bit lower than 90%, it means that even with no vaccine hesitation and even if we could vaccinate children with it, we won't hit the required target for herd immunity. This has been assumed to happen for a while now, and might be the least surprising bit of news. However, there are a few recent findings that have prompted changes in messaging, for example with regard to masking. The key issue here are the finding that folks with breakthrough infections have similar viral loads as unvaccinated folks. What does it mean? Fundamentally there some vaccinated folks that get infected with SARS-CoV-2. That in itself is not surprising. Historically, breakthrough infections happen for most vaccinations at low frequencies. Most of the time the focus is on illness, i.e. symptomatic manifestations of infections. However, as mentioned, the possibility of asymptomatic spread has changed that. The fact that vaccinated folks still have high titers means that folks with breakthrough infections could infect others and especially unvaccinated folks are at risk of becoming seriously ill. Vaccinated folks, for the most part do not seem to develop serious symptoms anymore, but it means that vaccinated folks could unwittingly infect and endanger un-or undervaccinated folks. This has prompted a reversal in the masking recommendation. Moreover, it has made many infectious disease experts nervous as in many countries mask mandates are being lifted. Unknowns: There are still many open questions. For example, in the US, the delta variant is causing more illness in younger folks, including children. It is not clear whether this is really a property of the virus, or just because younger folks tend not to be vaccinated. It is not certain whether the vaccine effectively protect from long-haul COVID symptoms. The rate of breakthrough infections is unclear, we know the lower end of the estimate based on detected cases, but since folks without symptoms typically do not get tested, we do not know exact numbers. Even in a highly vaccinated community it is possible that there is a large enough reservoir to allow new variants to develop. https://www.cdc.gov/mmwr/volumes/70/wr/mm7031e2.htm?s_cid=mm7031e2_w https://www.medrxiv.org/content/10.1101/2021.07.31.21261387v1 Discussion points: As a whole it means that we are heading into new territory during fall and winter. The big question is whether the current vaccination rates are good enough to prevent mass hospitalization or will easing of restrictions make folks forget that the disease is still there and cause a new surge. Vaccine hesitancy will add fuel to this potential fire. The communication in many countries/states/provinces have been confusing to say the least and quite a few folks I have talked to seem under the impression that there is little danger left, despite the fact that even in highly vaccinated countries, especially younger folks are barely hitting 50% of full vaccinations. Moreover, most folks in the world are still unvaccinated, meaning that we will need to prepare for more variants. Everyone is being sick and tired of the situation, yet undoubtedly the world has changed yet again (and will continue to do so). A big decision at some point is to establish how many deaths we are comfortable with. With regard to flue, for example, the number is surprisingly high across countries and by any estimate, COVID-19 is going to eclipse it, unless very high vaccination rates are maintained, which is notoriously difficult. Edit Aug, 19, 2021: A new preprint has come out indicating that with the Delta variant Pfizer might only be 42% effective at preventing infections (not disease!) and Moderna was about 76%. https://www.medrxiv.org/content/10.1101/2021.08.06.21261707v1 This seem to highlight that behavioral prevention is still going to be important.
    6 points
  18. I’m on the autism spectrum myself. The problem here is that we can’t isolate a specific sensory stimulus at the exclusion of everything else. So in this particular example, the stimuli coming from eye contact and his spoken words are both present, and both equally prominent simultaneously, which makes it difficult to focus on the actual content of either one of them. Averting eye contact simply makes it easier to focus on the person’s speech, so a lot of autistics will do this unconsciously and automatically. A better example would be a room full of people all talking to each other; it is very hard for me to just focus on what the person in front of me is saying, since I am forced to equally register all the other conversations in the room at the same time. There is no functioning filter there to limit and focus sensory stimuli - which is why we get sensory overload in certain stimuli-rich environments. Note that this is a matter of degree - different environments affect different autistic people in different ways and degrees.
    6 points
  19. 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.
    6 points
  20. This is my 1000th post! Time to celebrate, This is a fine moment to open the Islay Single Malt I got for Christmas. Cheers from Ghideon, to all new and old form members!
    6 points
  21. It might help, if you @Angelo would first, in an objective tone, lay out exactly what you believe Tyson's argument to be, and the steps in his reasoning (as far as they are provided and assuming they are truthful). As far as I understand the simulation hypothesis, is that it is based on chance and likelihoods coupled with some very specific assumptions; however the things you say, and the way you ask your questions and/or comment on other peoples posts, to me seems to indicate that you (at best) don't know the full reasoning behind the simulation hypothesis (or you do understand it, but are wilfully creating strawmens). Additionally, it would be great to present the strongest argument(s) for the simulation hypothesis, and not immediately assume that Tyson and other people agree on everything. If he has some illogical reasoning or assumptions you don't agree with, then it may be good to find a better version of the argument, instead of immediately disregarding the entire hypothesis. If you are really interested in understanding Tyson's and other people's point of view on this, it would help to start with a detailed summary/explanation of the hypothesis, because I could explain it (as far as I understand it), but I doubt the explanation is similar to what you think it is. And if you aren't sure on WHAT people belief, then it is very strange to already think of it as nonsense, therefore (assuming you have good reason to think of it as nonsense) it should be easy for you to explain it (in your own words, please don't just link something, that doesn't test your current understanding). Kind regards, Dagl
    6 points
  22. My son holding my grand daughter!
    6 points
  23. Implicit here is a false suggestion of equivalence. That’s not the case. If a kid walks down the hallway in school and gets punched in the face and has his lunch money stolen, is it his fault for carrying lunch money or walking freely down a public hallway? No, of course not, but if you think “both sides” need to compromise here then that’s precisely what you’re saying... that the kid is equally guilty as the bully. Trump last year said send a bill to my desk and I’ll sign it. Republicans were in control so drafted their version. Democrats agreed to vote for it and provide billions of dollars for this wall last year, and the compromise was that dreamers would get status. Trump backed out. He moved the goalposts. He said I want more. Funding ran out in December and Democrats said, fine... we’ll sign the republican bill yet again... we’ll compromise... but want money allocated to smarter enforcement options. A wall is not smart, and even countless republicans across the nation and some on Fox News itself agree. Trump said no. Eff you, a wall or nothing. Democrats said, Republicans still control all 3 branches of government. Since they’re in control, they need to get their president onboard. They couldn’t. President had a tantrum. Paper tiger in the Oval Office. Said he wants a shutdown. Shutdown began. Democrats took control of the house in January and on Day 1 passed a bill to reopen the government. Senate leader McConnell would not even bring it to the floor. Democrats later said they’d give more money for border protection, just not a wall. They compromised. President still refused. Wall or nothing. Eff the workers. Democrats passed multiple other bills to reopen parts of the government and agreed to negotiate terms on border security. They AGAIN voted for the previously passed republican funding bill from December. McConnel AGAIN wouldn’t bring it to the floor. Today Democrat senators continued to pressure McConnell to bring the bills up for a vote. He refused. He said it was pointless because the president won’t sign. Democratic Senators reminded him that they had the votes to override a presidential veto... that they are a co-equal branch of government and need to act like it. McConnell left. He just walked off the floor. Still no vote. Democrats will again pass a bill tomorrow to reopen the government. The bill will be the one drafted and previously agreed to by republicans. I agree there’s a lack of compromise here, but to say it’s equal across the aisle is absurd. The bully is trying to steal the lunch money. The other side has already offered to share their sandwich with him and are not at fault merely for having lunch money in their pocket.
    6 points
  24. Right, he is saying that the speed of light in both directions is the same with respect to any inertial frame as measured from that frame. So in the following example we have two observers. One standing along the tracks and the other traveling along the tracks in a railway car. Two flashes are emitted from two points along the tracks that are equal distance from the track observer. the light from these flashes arrive at the midpoint observer at the same moment as the railway observer is passing him. Thus both observers detect the light from the flashes at the same time. Like this: For the midpoint observer ( or anyone at rest with respect to the tracks) these flashes were emitted simultaneously, as shown by the expanding circles: However, for the railway car observer, events have to occur differently. He still detects the light from both flashes simultaneously, and they arrive when he is adjacent to the track observer. But unlike the track observer he has not remained halfway between the emission points the entire time. He is not an equal distance from the emission points when either of the flashes was emitted. But he must also measure the speed of light for each of the flashes as being the same relative to himself. But since the distances each of these flashes travel relative to him are not the same, in order for the light of the flashes to reach him simultaneously, they must have left at different times. And the sequence of the events for him occur like this: For the track observer, the flashes are emitted simultaneously, but for the railway observer they are not. This is the relativity of simultaneity: Events that are simultaneous in one inertial frame are not so according to another which in relative motion with respect to the first frame.
    6 points
  25. I am pleased to now add CharonY and Strange to the list of gullible fools wonderful people willing to sacrifice their time for the greater good here at SFN. Congratulations!
    6 points
  26. Because the transfinite ordinals and cardinals are not real numbers. The subject of the thread is "The geometry of the real number line." That's YOUR topic, right? So we are discussing the real numbers. The transfinite ordinals and cardinals are fascinating in their own right, but have nothing to do with the real numbers. In fact the transfinite ordinals (and the cardinals, which are technically a proper subclass of the ordinals) do not intersect the real numbers at all. The transfinite ordinals and cardinals are neither subclasses nor superclasses of the real numbers. They're just a completely different subject. If you are trying to understand whether there's a largest number in [0,1), it's no help to think about transfinite numbers, since transfinite numbers are not in that interval at all. Does that make sense? Besides, haven't you already said you are only interested in the standard real numbers? Why are you suddenly interested in mathematical objects that are NOT standard real numbers? This para does not make sense. First, we can't use transfinite numbers in a discussion of the reals, because transfinite numbers are not members of the real numbers. We can of course use transfinite numbers to talk about the cardinality of various subsets of the reals, but that's not what we're talking about here. Ah. Well, the length of a single point is zero. The length of [0,1] is 1, and so is the length of [0,1). The addition or deletion of a single point makes no difference when we're calculating the length of an interval. I'll keep my clothes on if it's all the same to you, thanks. The length of a point is zero, so adding or deleting a point can not make any difference in the length of a line segment. I think what you are saying is that the intervals [0,5] and [5,6] both contain the number 5, and that is correct. I don't see how that helps you to find a largest number in [0,1). So the two intervals would "bang into each other" at the point 5. You are correct that 5 is an element of both intervals. But as a point, the number 5 has length 0. The two facts are both true. 5 is a point on the real number line and it has length 0. So yes, two points of zero length can still bang into each other, if you want to put it that way. Remember, Newton showed that you can reduce gravitational calculations to "point masses." So if it helps, you can think of them that way. They are points with zero dimensions, zero length, and zero volume, but they still pack a punch. I'm not saying that's any kind of mathematical argument, but if it helps you to resolve this particular objection, I'm ok with it. In your imagination. But the proof that there is no largest number in [0,1) should cause you to realize that your intuition is flawed. It should give you a better intuition. Now there is nothing wrong with having such a faulty intuition. Pretty much everyone has faulty intuitions about the real numbers before they see these technical discussions. But now that you've seen a formal proof that there is no largest number in [0,1), you should be willing to realize that your intuition is faulty, pre-mathematical as it were, and you should update your intuition. What exactly about the proof are you still unconvinced about? I asked you that in my previous post. It's no good for you to say you're unconvinced, without saying exactly what aspect of the proof you are unsure about. If you could focus on the proof we could discuss that. I can't discuss onions or bodies of water or vague pre-mathematical notions of the real numbers. It's more helpful to focus on the actual math. We are not going to discover a largest number in [0,1), because we already proved a few posts back that there is no such thing. Now I'm confused. Didn't you see and more or less agree with the proof I already posted? There is no largest number in [0,1). Proof: Suppose you claim that x∈[0,1) is the largest number in that set. Take half the distance between x and 1 , namely 1−x2 and add it to x , giving: x+1−x2 You can see that we have the strict inequality x<x+1−x2<1 so that x is not the largest number in [0,1) after all. Since x is entirely arbitrary, we have just shown that there is no largest number in [0,1). You have already seen this proof, and more or less said you agree with it. But now you are saying "Are you sure there are proofs?" You already saw the proof. Yes, I'm sure there's a proof, I've now stated it twice. And you've agreed to it. So I have no idea what you mean by asking if I'm sure there's a proof. Ah ... ps ... you said, am I sure THEY are proofs. Are you asking if the proof I gave is actually a proof? Yes, I'm sure. If there is any part of it you are unsure of, I wish you would ask about it or say which part you find unconvincing, so that we can focus on that.
    5 points
  27. We instituted a version of a safe zone in my household when my children were too young to drink. Coming home drunk was a violation of our rules, but if my kids were out with the car and under the influence, they could call home for a ride, 24 hours a day, with zero retribution for drinking. I was willing to accept law breaking and rule breaking if it meant saving them from harm. I suspect people who aren't willing to accept safe zones for drug use among strangers will usually feel differently if it is a loved one whose life is at risk.
    5 points
  28. Why don't you fuck off to Russia and enjoy the delights of their state media. Stop dragging this topic into irrelevance. If you've got an axe to grind, make your own thread. We don't need your bile making a difficult subject more difficult to navigate. You are making this thread stink of red herrings.
    5 points
  29. The attachement from the international libraries association is self explanatory. Although not specifically for scientific matters I thought it was particularly well presented and a good candidate as a sticky on this site.
    5 points
  30. If we go back to the topic of C-16, it seems to me - and correct me if I'm wrong, his objection is that by disallowing discrimination of people based on gender identity or expression, that would prevent him from refusing to use a person's preferred pronoun, thus limiting his free speech. 1) There is a non-trivial proportion of humans who are actually born biologically intersexed, or conditions such as androgen insensitivity that will cause an individual's genitals to change from female to male during puberty. Not to mention the significant body of research demonstrating the neurological basis of transsexuality. He is basically asking that his delusional denial of biological reality be protected, which to me, seems pretty fragile and snowflakey. 2) Based on 1), how would he know an individual's sex at birth, or current physiological state? If someone says they are he/her/they, how is he to know the phenotypic or neurological reality of that? Even if it changes mid semester? If you tell me you're a Christian, and I deliberately call you a Muslim and presume you follow the tenets of Islam - that would currently be discrimination and he doesn't seem to have a problem with that. It would appear that applying it to gender identity is cherry picking. 3) No one is forcing him to believe in gender dysphoria, or accept the biological fact that gender is not fixed at birth. They are compelling him not to discriminate against those who do. As such, his right to question the validity of gender fluidity remains protected. The only thing being taken away is his "right" to discriminate against specific individuals based on their identity. Which brings the argument down to "You are denying my "right" to treat people differently based on their gender identity" which, yes - is the intent of the law. Watch me play this tiny violin.
    5 points
  31. Yes @joigus, I lurk in the shadows and follow proceedings here whenever I get the opportunity At present I live in the jungles of Thailand, having recently been ordained as a monk, and do not have access to anything other than an old mobile phone with spotty and slow internet access, so I’m not really in a position to participate in discussions. It’s just too slow and painful to type this way. I will return once I get access to better infrastructure - perhaps some time next year. Satellites in orbit are in free fall - place an accelerometer into them, and it will show exactly zero at all times. No proper acceleration -> no force acting on them. And yet they don’t fly off into space, but remain gravitationally bound into their elliptical orbits. Clocks in them are also dilated wrt to far-away reference clocks, which is also a gravitational effect. Thus, no force, but still gravity. Newtonian forces are simply bookkeeping devices, and as such they often work well - but only in the right context. Their nature is descriptive, but not ontological. They are not very physical either, given that they are assumed to act instantaneously across arbitrary distances. The strong, weak, and EM interactions aren’t ‘forces’ in that sense at all, since they work in very different ways. They are only sometimes called ‘forces’ by convention, for historical reasons. They ultimately arise through the breaking of symmetries, with the particles involved being irreducible representations of symmetry groups. Finally, it should be noted that physics makes models, that’s what it sets out to do - and as such it is always descriptive rather than ontologically irreducible. So, asking whether gravity “really is” A or B, or whether A or B are “true” is fairly meaningless, since both A and B are descriptions of reality, but not reality itself. Like maps of a territory. The correct question is thus whether models A and/or B are useful in describing gravity, and in what ways and under what circumstances they are useful. So - Newtonian gravity is sometimes useful, but GR is more generally useful, as it gives more accurate predictions for a larger domain. So for now the best answer to “what is gravity” that we have is a purely descriptive one: it’s geodesic deviation, and thus a geometric property of space time. To put it flippantly, it’s the failure of events to be causally related in a trivial manner. Future advancements may upend this picture in the high-energy domain, perhaps radically. We’ll see. I’m sorry I can’t contribute much at the moment, but I’ll leave you with the above thoughts. I could have written much more, but it’s too much of a pain on a small mobile phone screen.
    5 points
  32. 5 points
  33. Three of those images imply too much power in the wrong place. The other is a horse.
    5 points
  34. Volcanic lightning is hard to beat. https://en.m.wikipedia.org/wiki/Volcanic_lightning Calbuco, The Awakening.” ... Calbuco Volcano is located in the lakes region south of Santiago, Chile’s capital city and is one of the 10 most dangerous volcanoes in the country. After more than 40 years of inactivity, the day April 23 the volcano erupts, spewing more than 200 million tons of ash https://www.dailytelegraph.com.au/news/photos/national-geographic-photo-contest-2015/image-gallery/a2afa2087ecd4f4d62475d231b129e31
    5 points
  35. Interestingly, this too is mistaken. Decades of evidence shows rather consistently that the riots get more out of control and the property damage gets worse the more police are present. From 50 years ago: https://belonging.berkeley.edu/system/tdf/kerner_commission_full_report.pdf?file=1&force=1 From 5 years ago: https://www.washingtonpost.com/posteverything/wp/2015/05/01/when-police-ratchet-up-the-force-riots-get-worse-not-better/ And from 5 months ago: https://www.themarshallproject.org/2020/06/01/why-so-many-police-are-handling-the-protests-wrong
    5 points
  36. The 'bowling ball on a rubber sheet' is a two dimensional reduction of a 4 dimensional configuration. It has multiple problems, one of which is that you can observe it from an embedding third dimension. Space-time has no embedding dimension; both the bowling ball and you, the observer, would need to be intrinsic to the rubber sheet ( i.e. also two dimensional ). A three dimensional representation would already get rid of some problems, but not all. Picture a three dimensional grid, where x, y, and z axis divide up the space into cubic elements. A mass placed in this space would curve the x, y, and z lines such that the elements are moreskewed, and smaller, as you get closer to the mass. That is 'space' curvature, and one aspect of gravity, but already much harder to visualize than the two dimensional example of the bowling ball/rubber sheet. Actual gravity is four dimensional 'curvature' of space-time, and I can't help you visualize that as it is impossible. Some problems are just not suited to visualization, but understanding even just the basics of the math goes a long way to clarifying things.
    5 points
  37. Today I learned that skills improved by participating here on scienceforums can, at least in some minor way, be helpful in the current virus situation. I joined a local initiative where students studying from home can ask about math and physics. Debating science here has made me more confident regarding mainstream science and how to respond with useful hints (instead of solutions) to homework questions.
    5 points
  38. Element 115 (moscovium) has a half life of about half a second, so is not very practical as a target. https://en.wikipedia.org/wiki/Moscovium (And I doubt that element 116 can be produced by firing protons at the nucleus.) "Immediately decays"? It is true that the half life of livermorium is less than that of mosocvium; but it is not immediate. Livermorium decays via alpha decay. In other words, it emits a helium nucleus (a pair of protons and a pair of neutrons bound together). https://en.wikipedia.org/wiki/Livermorium It does not emit anti-protons. That would violate all sorts of conservation laws. https://en.wikipedia.org/wiki/Conservation_law And anyway, what would be the point? This can only be of interest to people who think that antimatter=magic. What are you going to do with these anti-protons? Presumably combine them with some protons to generate energy. But you can't get any more energy out of that than you put in. So the whole process of accelerating some protons, transmuting 115 to 116, then capturing the anti-protons and then generating some protons for them to interact with, then controlling their interaction and directing the energy ... all takes energy. And must run at less than 100% efficiency. https://en.wikipedia.org/wiki/Laws_of_thermodynamics So you are going to get less energy out than just using shooting the original protons out the back of the rocket. Or using the heat from the rapid decay of the moscovium (you will be left with no useful fuel after a few minutes, anyway). There is nothing to critique here. This is just meaningless word-salad from a bad SF book. No references here because there is no such thing as "Gravity-A waves", "Gravity B waves" or "Gravity Amplifiers". Also, gravitational waves (which do exist) are not directly related to gravity. Gravitational attraction is not a wave phenomenon. Also, gravity is only attractive; there is no practical or theoretical reason to think that somehow causing gravitational waves (if that is what the ignorant author means) to interfere would cause any gravitational effect (either pull or push). Gravitational waves cause stress (stretching and shrinking) in directions orthogonal to their direction of travel. This effect is too small to be significant, unless you are a few miles from two merging back holes. https://en.wikipedia.org/wiki/Gravitational_wave Gravity waves are something completely different. They are a phenomenon in fluid dynamics and have nothing to do with gravity (in the sense implied here; they are caused by gravity, not a cause of gravity). https://en.wikipedia.org/wiki/Gravity_wave It is almost as if the author doesn't know what they are talking about. And are just stringing together a bunch of words they don't understand. See anyone can do it.
    5 points
  39. A better question is why [math] 10^{-43}[/math]. Would it help to recognize that number is one unit of Planck time with our current observable universe to the volume of 1 Planck length. The temperature being equivalent to Planck temperature. The Planck units are in essence boundary conditions on which our ability to mathematically describe in essence breaks down into Infinities and nonsensical results. You often only hear the space and time axis in essence flipping roles for the GR descriptive but cosmology must also include both macro and quantum effects. So its good to understand how the limits of the macro and quantum theories apply. (String theory also recognizes these limits) One detail as mentioned in this thread is were describing our Observable portion in essence the limits of shared observable causality with our current universe. Time being a measure of rate of change or duration you in essence need a dimension in order to have something to measure or even something that must be able to change. However one must also realize that the t=0 represents the collective worldlines of all particles in our observable portion extrapolated from the closest we can mathematically describe and potentially measure. In the closest to pointlike we can describe. It does not represent any time outside our region of shared causality. In essence [math]10^{-43}[/math] is the origin of time for all potential worldlines in our observable universe that are extrapolated to the beginning of our observable universe (as the emitter event).
    5 points
  40. Fake news! It was a perfect renewal! Absolutely perfect. In a world where even my fridge can give me reminders, I still managed to forget. Luckily Capn was able to social engineer his way through my answering service who sent a page out to me stating "CAPN REFSMMAT - RE: WEBSITE". They even listed a hospital he was calling from 😂. I wasn't on call today so when I heard my answering service text me I about lost my mind until I saw who it was.
    5 points
  41. No. Space-time should not be comprised of anything like dough. It is not substance-like at all. The concept of space-time is just the recognition that the measurements of space and time are frame dependent and not absolute. The analogy is that in Newtonian physics, space and time are treated like North/South vs. East/West. In such a situation everyone, no matter what direction they are facing, all agree on these directions. Everyone, for example, agrees that town A is 40 miles North and 30 miles East of town B. However the Space-time manner of treating this is that each person uses his own sense of Left/Right and Front/Back. Thus one person facing one direction will say that town A is 30 miles to the left of and 40 miles in front of town B, while someone facing in another direction would say that town A is 50 miles directly to the right of town B. It makes no more sense to think of space-time as being "substance-like" than it would to think of Left/Right-Front/Back as being "substance like". Now I also realize that in GR, it is said that Space-time "curves" in the presence of mass. And to many people this implies space-time being a "structure or substance". This is not what this means. "Curvature" of space-time really just means that the geometry rules governing it are non-Euclidean. In other words, the rules of plane, Euclidean geometry just don't hold.
    5 points
  42. I'll clarify for him. For the reaction mass to produce an upward force on the rocket, it has to be accelerated downward relative to the rocket. In order to return that mass to the top of the rocket, any downward velocity the mass has relative to the rocket has to be stopped and reversed. This is an acceleration just as much as the one producing the upwards force on the rocket (acceleration is either change in speed, direction or both). This action will exert a force on the rocket opposite to that caused by accelerating the fuel downward. The end result of this force will be counter any upward movement by the rocket. This ends up with the net movement of the rocket as being zero. There is no way around this. There is no "clever" way to "fool" the rocket into having net movement by recirculating the fuel/reaction mass.
    5 points
  43. thethinkertank has been placed in the queue for spamming the forum with an impressive amount of nonsense.
    5 points
  44. It seems you have to know an awful lot these days not to offend people, other than not saying anything. Good manners, adherence to tolerant principles, and absence of mal-intent does not seem to be enough.
    5 points
  45. Trump has relentlessly insisted for 3 and a half years that Mexico would pay for a border wall. No nuance, no doubts, no maybes, Trump said Mexico would pay for the wall. He held rallies a;; over the country leading people in chants where he'd say "who's going the pay for the wall" and stadiums full of supporters when yell "MEXICO". Trump has given interviews and briefings where he'd cut reporters off and insult those who challenged how he'd get Mexico to pay. Now here we are with the govt shutdown as Trump demands a newly elected House majority give him the money tax payer money for his wall......and some people are actually trying to launch arguments blaming Democrats .
    5 points
  46. Kidnapper abducts 50 of your colleagues. Says he will only release them if you let him have sex with your wife. You say, no. Are you now responsible for the 50 colleagues being held hostage? Of course not. The magnitude of stupid required to suggest such a thing is overwhelming. Kidnapper says, fine. Let me have sex with your wife, I’ll also return the many items I stole from your home last year, and will additionally agree not to steal anything else for 2 more years. Agree to this and I’ll release the hostages. Understandably, you again say, no. Are you now responsible for the 50 colleagues being held hostage? Of course not. Are you the one now at fault for “not compromising” with the kidnapper? Of course not. The magnitude of stupid required to suggest such a thing is overwhelming. “What if you just let him put it in the butt?? that’s a compromise” ... that’s where this conversation has devolved into. No. Not just no, but hell no. Yet that’s precisely what’s happening here when posters keep saying Democrats are the ones responsible despite their MANY votes attempting to reopen government and to get workers paid, and despite the obvious obstacle here being Mitch McConnel and the president for refusing to even allow a vote.
    5 points
  47. Accusations of deliberate, widespread bias and falsification of results, across every major institution (in several different nations) doing climate science and climate modelling really does require evidence. Evidence of which, if this misconduct was really going on, would leave a much clearer trail than a couple of questionable phrases in one email exchange. There is no such evidence, just accusations or it would have come to light a long time ago. Does anyone really think successive governments across the developed world, many with demonstrated hostility to climate science's reports and studies, could not uncover that extent of deliberate bias and collusion? Or that level of incompetence not be noticed within long running non-secret institutions where high standards - with everything on the record - are essential to everything they do? The claims of bias and incompetence are all accusation and no evidence. We have agencies that can pick out guarded exchanges between anonymous terrorist conspirators but they can't catch out hundreds (thousands?) of published working scientists conspiring within and between legitimate government agencies? They haven't exposed this alleged conspiracy of incompetent science and world subjugation because it doesn't exist. Making casual accusations against ordinary people doing their job (better than some people like) is, itself, a serious kind of wrongdoing (slander), besides being very insulting to people who, so far as evidence goes, have been doing their jobs with all the appropriate care and attention and honesty. All that professional effort to work out how our climate system really works, only to be casually accused of being everything from colluding in incompetence to engaging in a global conspiracy! What upsets me almost more than anything else, is that climate scientists have given us an extraordinary gift in the forewarning and foresight they have given. The window of time to transform the way we do energy has been precious beyond price; that we have been squandering it is not the fault of climate scientists failing to communicate. The persistent counter-messaging by opponents and obstructors is indicative of a far more insidious conspiracy of biased incompetence than even their made up version of conspiratorial climate scientists and green-socialist-globalists. In the face of that kind of politicking, and given the seriousness of the climate problem it is climate scientist who do not resort to advocacy that I find questionable. Mistermack - I think you are too gullible and that you have been gulled. I don't expect you to believe anything from me even if you did give it due consideration. Or from Al Gore or from Greenpeace or whoever; however, I do think you should consider taking the Royal Society and National Academy of Sciences, the NOAA, NSIDC, NASA, CSIRO, Hadley CRU and so on, seriously.
    5 points
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