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  1. 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 sometim
    8 points
  2. 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
  3. 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
    8 points
  4. 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
  5. 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
    8 points
  6. 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
    7 points
  7. 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
    7 points
  8. 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
  9. SR does not claim that such an observer will always see the Earth clock run slow, if by see, you mean what his eyes or instruments directly record. In this usage of see, he will see it run at a rate of T = To ((1-v/c))(1+v/c))1/2 where v is positive if Earth and the Observer are receding from each other and negative if they are approaching each other. A factor contributing to this observation is the the distance and thus the propagation time for signals is constantly changing, getting longer when receding and getting shorter when approaching. This factor works out to be c/(c
    7 points
  10. 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
    6 points
  11. 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 o
    6 points
  12. 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
  13. 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 wi
    6 points
  14. My son holding my grand daughter!
    6 points
  15. 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
    6 points
  16. 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:
    6 points
  17. 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
  18. As I said in my previous post. Relativity makes no such claim when it comes to what an observer will visually see. This is a straw-man argument based on a misrepresentation of Relativity. To explain the difference between what the observer would visually see vs. what he is conclude is happening, we'll use some space-time diagrams. First consider two clocks separated by some distance and stationary with respect to each other. The blue line is our "observed" clock and the green line is our "observing" clock. The scale is such that light, shown as the yellow lines, is
    6 points
  19. Stephen Hawking has passed away at the age of 76 on Pi day, 3/14/2018. http://www.bbc.com/news/uk-43396008 https://www.theguardian.com/science/2018/mar/14/stephen-hawking-professor-dies-aged-76?CMP=fb_us
    6 points
  20. This is the rhetoric pushed by billionaires who don't need the government the way most of us do. Isn't it pretty obvious that the billionaires in politics today are only interested in removing restrictions on themselves, and limiting the money spent on the rest of us? These folks have been hammering this message of "bad government" and "sleazy politicians" for decades, while actively being the representatives with the sleaziest behavior, doing everything they can to make the government bad. They don't care if you have access to libraries, museums, parks, swimming pools, or healthcare. The
    6 points
  21. Puerto Rico agrees. Black athletes agree. The anti-fascist movement agrees.
    6 points
  22. Why do you limit your options to 'god did it' or 'everything popped out of nothing'? What about it didn't start, i.e. it's always existed? What about 'we don't know'? Also, as i understand it physicists have found that things do simply pop into existence. And yes, i'm frequently astonished by existence. Why does that imply god? I like this question. Many people seem to question that the universe could either just pop into existence or that it has always existed - but are happy to ascribe these exact same properties to something they call 'god'. Either way something has thi
    6 points
  23. 5 points
  24. Three of those images imply too much power in the wrong place. The other is a horse.
    5 points
  25. 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
  26. 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
  27. 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 c
    5 points
  28. 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 woul
    5 points
  29. Thank you for all your feedback. I’m currently working on some mental health issues and cannot reply on give the answers the time that I would like to in regards to research and time and I struggle to express the concept fully and accurately, more to come but I have to work on my stability at this time kind regards David Wavish
    5 points
  30. 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 h
    5 points
  31. Join a science forum and post once...
    5 points
  32. Brevity and sarcasm. No wonder no-one knows WTF you're talking about half the time.
    5 points
  33. 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
  34. It's pretty easy, and it's been done to death. Most of their arguments are strawmen, in that they make a false or misunderstood claim to attack, instead of a more difficult, legitimate claim. For instance, that the creation of proteins is astronomically improbable, therefore it couldn't have happened. Since they mistakenly think the universe is only a few thousand years old, they can't accept that evolution had millions of years to miss before it finally hit. Many of the arguments are nitpicking Darwin, as if the theory began and ended with him. They ignore what every scientist knows, th
    5 points
  35. 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
    5 points
  36. 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 colle
    5 points
  37. We're working on it. http://indexsmart.mirasmart.com/IFCS2018/PDFfiles/IFCS2018-000128.pdf https://www.osapublishing.org/josab/abstract.cfm?uri=josab-35-7-1557
    5 points
  38. 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 an
    5 points
  39. You will find all relevant answers in this excellent resource: http://stopmasturbationnow.org/
    5 points
  40. I'll let you know about a "rule of thumb" with regards to science and the scientific methodology. First and foremost, before you let your imagination run free, searching/looking for any new ideas that are not mainstream, please make an effort to get to know the mainstream product, and why it is mainstream and held as valid by most scientists...learn its predictions that have been shown to be valid...research the experiments that have supported its validity...check out all the observational data that support it. Then if you really and truly believe there is a serious fault with the particular i
    5 points
  41. Here we finally have it! Proof of the existence of a creator? Best evidence yet!
    5 points
  42. I just wanted to express my heartfelt apology to the members of the forum. I was on suspension for a year for very indecent behavior. I hope I can rejoin your community once again.
    5 points
  43. Because I am a philosopher, not a scientist, and this is a science forum, I did not feel any obligation to vote on the issue. Most people, who have read my posts already know my view on the "click-it squad". I would also like to say that I do not see much value in the vote, as the people who are in the forum are reasonably happy with the way the system works, and the people who are not happy with the system have mostly left. So I predict that the vote will be self-confirming and retain the system. The one point that was brought up in this thread, about people arguing with accepted Sc
    5 points
  44. I'm told that when naked mole rats sit around shooting the breeze, they discuss how they are a clear aberration. Apparently domestic cats hold much the same viewpoint. Not to mention African Greys. It seems its a tendency of any reflective species to view itself as unique and special. You can probably eliminate any single species from the planet and the biosphere will continue pretty much as it was apart from some small, local readjustments. So you can replace the word "humans" in your statement with the name of any species . If you don't feel a Great White is not a supe
    5 points
  45. Others have already more than adequately addressed this, and I acknowledge you've mentioned it may have been a poor analogy, but just to close the loop... I said the job of POTUS was different from brain surgery and the precise skills that requires, not that it was simple. That's what happens when the US electorate votes in a man that is obviously unfit and unqualified and who received most of his votes by engaging in grievance politics... scapegoating mexicans, whipping up religious resentment for muslims, implicitly supporting klan members, stoking economic resentments, sayin
    5 points
  46. It is difficult to explain why you are wrong because you don't understand the subject and so you just reject the explanations (this has been true in all of your threads). And yet you are the one who constantly quotes the words of others but ignores the science. For example: Dalo: I don't believe X Others: Here is a simple explanation why you are wrong ... D: That's a bit vague, can you be more specific? O: <detailed explanation with evidence and a mathematical analysis> D: I don't need all that maths and what about [irrelevant sidetrack] O: Wha
    5 points
  47. First off, dark matter and dark energy are two different things and the reasons for expecting their existence are completely unrelated. The only thing they have in common is that they have "dark" in their names. The initial evidence for dark matter came from observations of how stars move in galaxies. Galaxies are formed from stars that are mutually orbiting each other. If we look at a galaxy, and estimate its mass by the matter we can see, we find that there does not appear to be enough to hold the galaxy together. At the speed the stars are orbiting, they should fly apart. We also
    5 points
  48. This would be very cool. Unfortunately, here in the USA, I don't see that happening any decade soon since there would be parental concern about the radioactivity as well as (unreasonable) religious concerns. * The discussion reminds me of a point I read once that if Darwin had been wrong, the discovery of DNA and how it works would have destroyed his theory and we would have been seeking an alternate mechanism. Instead the discovery of DNA lead to a refinement of Darwin's theory into the even more robust Evolutionary Theory. It is humbling to think of how Darwin, through o
    5 points
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