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3. ## iNow

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## Popular Content

Showing content with the highest reputation since 03/28/04 in Posts

12 points
2. ## Mike Smith Cosmos

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
3. ## Rules update: bad faith discussions

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
4. ## Matter creates gravity

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. $(t,x,y,z)=(ct,x,y,z)=(x^1,x^2x^3x,x^4)$ 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
5. ## When did God put the soul in humans during evolution?

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
6. ## So are quantum entangled or teleported particles instantly there

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

7 points
8. ## Can you be a scientist and still believe in religion?

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

7 points
10. ## My first thousand

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
11. ## Special Relativity - simple questions?

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+v) When you factor this out of the first equation you are left with the time dilation equation. This means that there are two things to consider: what you see happening to the Earth clock, and what is happening to the Earth clock. So while while receding from the Earth, the observer will see the the 1000 Hz signal as being 500 hz and the Earth clock as ticking 1/2 as fast as his own,. Taking into account the effect of the increasing distance, he will determine that the Earth clock is ticking 0.8 as fast as his own. He will meet up with the object when his own clock reads 1.01.2022 (as the distance between Earth will be only 1.2 ly as measured by him and this is how long it takes to traverse this distance at 0.6c.) He will see the Earth clock reading 1.01.2021, but determine that it is 8.07.2021 on the Earth at that moment. Now at first, you might be tempted to think " But wait, if he sees 1.01.2021 on the Earth clock, and the Earth is, according to him, 1.2 ly away, wouldn't that mean that it should be 3.15.2022 on the Earth by his reckoning?" This is not the case. The light he is seeing at that moment left Earth at a time when the distance between them was less than 1.2 ly, so the time it took the light he is seeing took less than 1.2 years to reach him from the Earth. Now he accelerates in order to come start the trip back towards Earth. We will assume a minimal acceleration period. Now this is the part where people tend to get tripped up. After he is done and is now approaching the Earth and not receding, we will assume that he still reads 1.01.2021 on the Earth clock by visual means. However, he will no longer conclude from this that it is 8.07.2021 on the Earth. Instead he will conclude that it is 6.05.23. During the return trip he will see a frequency of 2000 hz from the signal and the Earth clock tick twice as fast as his own. But again, taking into account the decreasing distance effect, he will conclude that the Earth clock is ticking at a rate 0.8 as fast as his own. Thus he will see the Earth clock tick from 1.01.2021 to 1.01.2025, but conclude that it ticked from 6.05.23 to 1.01.2025 during his return leg. (see will see it tick off 4 years, but conclude that it ticked off 1.6 years. Again, it all come back to what happens during that acceleration period. As far as anyone at rest with respect to the Earth is concerned, nothing special beyond the standard SR effects take place. But for the observer actually undergoing the acceleration, things aren't this simple. For him, the rate at which clocks run depend on which direction they are from him relative to the acceleration he is undergoing and the distance from him in that direction. Clocks in the direction of the acceleration run fast, and those in the opposite direction run slow (beyond what he sees. This even effects clocks that share his acceleration. A clock in the nose of the Ship will run fast and one in the tail will run slow. ( in this case, since there is no changing distance between himself and the clocks, what he sees, will be in perfect agreement with what is happening to the clocks. While this may seem to be at odds with common sense, it is how a Relativistic universe works. A problem with your questions is that they only deal with particular points of the whole scenario without taking in the whole picture. It like comparing two men walking and only considering where they end up. Below we have the paths of two men, Red and Blue, over the same interval. If you just look at where they end up, you would conclude that Blue walked a shorter distance because he ends up closer to the starting point than Red does. But when you consider the whole interval, it is clear that Blue walked a further distance. The same thing is true with SR, if you only consider the end results, you are missing what is really going on.
7 points

7 points

6 points
14. ## autism brain connectivity

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
15. ## 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.
6 points
16. ## Last post of the first 1000

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

6 points
18. ## My grand daughter!

My son holding my grand daughter!
6 points
19. ## The Border Wall or Fence

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
20. ## What if Einsteins Definition of Simultaneity is incorrect?

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
21. ## SFN's New Moderators Thread

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

6 points
23. ## Stephen Hawking Passed Away 3/14/2018

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
24. ## Trump Effects

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. They have all those things taken care of due to their massive wealth, and object to taxes that make these things available to the rest of us. They've chosen to ignore our efforts that brought them great wealth, and instead spend money convincing folks that government needs to be dismantled for OUR good. And now they have this blatant racist sexual assaulter-in-chief who is morally and economically corrupt, and happens to have a deluded following all chanting about bringing down the Fed. Working class folks who think this billionaire has their backs while he whittles away at the very thing that has the best chance of making all their lives a lot better. The wolves have tricked the sheep into removing restrictive fences, and the sheep are all praising the freedom.
6 points
25. ## Why doesn't truth matter & middle ground

Puerto Rico agrees. Black athletes agree. The anti-fascist movement agrees.
6 points
26. ## God and science

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 this property - why not discard the middleman and simply ascribe it to the universe. Depends how god is defined. A god that set up the conditions for the big bang but does not intervene at all thereafter would be impossible to detect, at least with our current capabilities. A personal god that answers prayers and parts seas has been pretty well debunked. Such a god would be easy to detect - we would just look for instances where the laws of physics contradict themselves (i.e. the rules change) - seas start to part, lakes turn into wine, whatever other crazy stuff you think a god might do. There is no sign of such a god.
6 points
27. ## What taxes a billionaire?

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.
5 points
28. ## Is Gravity a Force?

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
29. ## Transgender athletes

I watch MMA. Some women in the sport have raised concerns about transgender athletes, which is how it came to my attention. Some in the medical have put forward scientific reasons to legitimise this concern, others refute these reasons, and that debate continues within the medical community (links have been provided in the course of this thread). To have these concerns just brushed away as ridiculous, and to equate them with resistance against gay marriage is unhelpful at best. It's the sort of rhetoric that pushes people toward Trump and Brexit, as it exacerbates the us vs them attitude that precludes nuanced debate - the nuance here being that having concerns about transgender athletes does not automatically make you transphobic (although it's likely true that all transphobes oppose all trans athletes and will leverage legitimate concerns to muddy the waters). It may turn out that these concerns are unfounded, but i would hope, on a science forum of all places, that the concerns were addressed rather than being dismissed simply ridiculous. It is patronising.
5 points
30. ## I will no longer post on your forum for the following reasons.

Lol I’m reminded of this
5 points
31. ## A very tough (and possibly controversial) poll about sexual abuse and rape

While this thread is closed and (I think) being the only person who identifies as female in this thread, I just wanted to provide a little food for thought. Of all the women in my life with whom I am close to, I can't think of a single one who hasn't been sexually assaulted or raped by a man at some point in her life. I cannot say the same about the men I know wrt to false accusations. Anecdotal I know, but something to think about.
5 points
32. ## The Official JOKES SECTION :)

I can't unsee it. Eh?
5 points

5 points
34. ## FTL thought experiment

When you arrive at point C, you will see the same light coming from both stars as someone who never moved from point C; Light that left both stars 5 yrs ago. You see both stars as they were 5 yrs ago.
5 points
35. ## The Official JOKES SECTION :)

Three of those images imply too much power in the wrong place. The other is a horse.
5 points
36. ## Gravity

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. ## The world has changed...

The 'economy' is not just a money making mechanism for the wealthy, Phi. It is the means by which most of us feed, clothe, house ourselves and our families; it's how we survive. I have no problem with the economy 'going for a sh*t' as long as it saves lives. But if it 'goes for a sh*t' for too long, people start losing their life for reasons other than the pandemic. That is the balance that has to be struck; dying by starvation is just as bad as dying by Covid-19. I believe that is what Danijel Gorupec meant.
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38. ## Bob Lazar

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.
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39. ## How can the cosmos be eternal?

A better question is why $10^{-43}$. 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 $10^{-43}$ 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).
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40. ## Space anchor idea

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
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41. ## Sorry about the downtime -- we're back!

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.
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42. ## Idea for a rocket engine

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.
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43. ## Members in the Mod Queue

thethinkertank has been placed in the queue for spamming the forum with an impressive amount of nonsense.
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44. ## Shamima Begum

Brevity and sarcasm. No wonder no-one knows WTF you're talking about half the time.
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45. ## climate change intensified the amount of rainfall in recent hurricanes

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.
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46. ## Why doesn't the electron fall into the nucleus?

Because the electron is not a classical particle (“little ball of mass and charge”), but a quantum object. As a first approximation, you can picture an electron as a 3D standing wave around the nucleus - you can only get standing waves of a given wavelength in specific places, which is why orbitals come in discrete levels. Crucially, there is a lowest energy level, which corresponds to the minimum distance an electron can be with respect to the nucleus (let’s assume here there is only one electron) - and that lowest energy level is not zero. Therefore the electron cannot fall all the way to the nucleus, it can only fall into its lowest energy level, which corresponds to an orbital that is still some distance outside the nucleus. This is a direct consequence of the laws of quantum mechanics, and coincidentally one of the questions that motivated the development of quantum mechanics in the first place.
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49. ## Time Does Not Exist

Ironically, under the title “time does not exist” it says “posted three hours ago”.
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50. ## Banned/Suspended Users

scherado has been banned for multiple instances of rule-breaking in his quest to become the Troll King. We apologize that his interruption in the normal rational discourse was all noise and no signal whatsoever. Roger Dynamic Motion has been banned, NOT for incessant hijacking and almost daily irrationality, but for failing to respond to requests for clarity, EVER. Discussion requires that we express our ideas so others can understand. We wish him good luck with his ideas, whatever they were supposed to be.
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