Jump to content

Leaderboard


Popular Content

Showing content with the highest reputation since 01/22/19 in all areas

  1. 8 points
    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.
  2. 5 points
    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.
  3. 5 points
    Brevity and sarcasm. No wonder no-one knows WTF you're talking about half the time.
  4. 4 points
    I think there are certain parallels between people believing in conspiracy and religious belief (religion being, from a certain point of view, the ultimate conspiracy) As folks have pointed out from time to time, when people do not use reason to arrive at a position, you will not be able to use reason to talk them out if it. Studies have shown that presenting such people with contrary evidence only tends to harden their resolve.
  5. 4 points
  6. 4 points
    Do you understand that one side lied, broke the law, got prosecuted + fined + reported to the police for criminal action, and the other side didn't? Are you somehow pretending that the situation was symmetrical? Well, it's hard to say. But racism is wrong, and played in favour of "Leave" Xenophobia is wrong, and played in favour of "Leave" External interference is wrong, and played in favour of "Leave" And the margin by which thecheats won is small. Imagine this was a football game and, after the match, it emerged that the winning side had played a "ringer". The acceptable outcomes would be that (1) The cheats would lose by default or (2) there would be a rematch. Why does anyone think it is reasonable to hold the future of the UK to lower standards of propriety than they would for a game of football ?
  7. 3 points
    That is not what "squaring the circle" means. Given a circle of area 1, yes, there also does exist a square also of area 1. That is not a problem. The problem is that from a line segment of length equal to the radius (or equivalently the diameter) of such a circle, it is not possible only using ruler and compass to construct a line segment to make a side of a square of the same area as the circle. The claim in your old book does not make immediate sense. It is true that if you are given a line segment of unit length, then you can quite obviously construct a square of unit area. But having been additionally given a circle of unit area would not be helpful in any way to do it.
  8. 3 points
    Greetings everyone, I am back 😎 So what is space made of? I think we need to first upgrade the question a bit and ask: what is spacetime made of? The answer to this is that it is a collection of events, to be understood in the sense in which the term is used in physics. To be even more exact, it is made of causal networks of events, i.e. events plus information about how those events are causally related. In terms of GR this is described as a manifold with its intrinsic geometry. Space on its own would then be just the spatial part of that network. So essentially, spacetime is a way to structure and organise information. Looking at it this way opens up some interesting questions, not all of which fall under the remit of physics: exactly what kind of information underlies this concept? Can this same set of information be structured/modelled in other ways as well? Is this structure intrinsic to the information, or is it something we impose more or less arbitrarily? Etc. P.S. It is important to remember that spacetime isn’t a physical “thing”, rather, it’s a mathematical model that captures certain aspects of the universe. It’s like a map we draw of a given territory.
  9. 3 points
    I can't see anything wrong with the quoted comments. ! Moderator Note As the only purpose of the thread seems to be to ridicule a member of another forum, the thread is closed. If you want to start a thread to discuss the relationship of mass and energy, then feel free to do so. But don't use it as an excuse to insult members of this or any other forum.
  10. 3 points
    What's wrong with that? Compassion is a huge part of many religions: the academic study of compassion might be useful - but it's not the same as the practice of compassion. When was the soul put into humans? Who cares - the answer won't make you a better human being, which is what religious teaching should be trying to help with. All this pretence at academia by 'religious' people seems to belie an insecurity and need for validation with science. Spiritual practices should stand on their own merits, anything that needs propping up with pseudo-pseudoscience should be left to fall. And honestly Gees, though there are some aloof people on this site, likely including myself, you are among the worst for it. Look at yourself before casting stones.
  11. 3 points
    There are many stunning photographs at APOD [Astronomy Picture Of the Day] some far more stunning then others...just type in APOD...a new one everyday. Here's another..... SEIS: Listening for Marsquakes Image Credit: NASA, JPL-Caltech, Mars Insight Explanation: If you put your ear to Mars, what would you hear? To find out, and to explore the unknown interior of Mars, NASA's Insight Lander deployed SEIS late last year, a sensitive seismometer that can detect marsquakes. In early April, after hearing the wind and motions initiated by the lander itself, SEIS recorded an unprecedented event that matches what was expected for a marsquake. This event can be heard on this YouTube video. Although Mars is not thought to have tectonic plateslike the Earth, numerous faults are visible on the Martian surface which likely occurred as the hot interior of Mars cooled -- and continues to cool. Were strong enough marsquakes to occur, SEIS could hear their rumbles reflected from large structures internal to Mars, like a liquid core, if one exists. Pictured last week, SEIS sits quietly on the Martian surface, taking in some Sunwhile light clouds are visible over the horizon.
  12. 3 points
    Your childish antics are fooling no one and they are taking away from the debate. We all know the meaning of what you've said and you trying to obfuscate their meaning with your hand-wavy tactics are just making you look foolish. It would have been much simpler to simply say "yes, that may not have been quite accurate" and move on.
  13. 3 points
    Again, this is the problem with just looking words up in dictionaries. "Religious faith" and "religious delusion" are not synonyms. The first is the subject of this thread. The second might be what some people think of religion (and hence is off topic). Stop trying to derail the thread with your misrepresentation of the meanings of the words being used in this context.
  14. 3 points
    An international research team, including a member of the Complexity Science Hub Vienna, investigated the role of "big gods" in the rise of complex large-scale societies. Big gods are defined as moralizing deities who punish ethical transgressions. Contrary to prevailing theories, the team found that beliefs in big gods are a consequence, not a cause, of the evolution of complex societies. The results are published in the current issue of the journal Nature. https://phys.org/news/2019-03-complex-societies-gave-birth-big.html
  15. 3 points
    Yes, he is, but QuantumT is using "you" to refer to all mods, and specifically referring to me in terms of shutting threads down. If the speculative thread dealt with physics, I'm the mod most likely to have interacted with you (over the years) Is it too fast? Well, that depends. We have received comments where people have complained about threads being left open too long, and begging us to close them. The people whose thread was shuttered rarely agree that they should have been locked. Bottom line is that there is no moderation strategy that will please everyone. The mods use their best judgement, built upon doing this for a number of years, and seeing a lot of people come and go. You in particular? In your first thread I tried to nudge you into compliance with our rules. That you needed to be more forthcoming with information. The thread was shut down after you announced "I will not participate in this open forum anymore" But you weren't true to your word. You came back, and to be honest, you lose a certain amount of goodwill from the mods when you pull a stunt like that. Once again, you were not forthcoming with information needed to support your position. That thread was closed, with a note that said if you did present supporting information, you could re-introduce the topic. I don't see where you took us up on the offer. The last one shut down was where you admitted you didn't understand the physics, and yet had a conjecture. I explained that this was not living up to our expectations, and at this point you had twice been given feedback on the matter of being able to support your ideas. Thus I had zero confidence that simply giving some feedback and letting the thread continue would improve matters. That was your third strike. The fact that you are placing the blame elsewhere tells me you haven't absorbed this feedback at all. So the question that I have is how many chances do you expect, when you show no improvement in your behavior?
  16. 3 points
    And I thought it was something to do with corona
  17. 3 points
    I'm not going to quote snipe back and forth. I'll just post my thoughts in hopes of finding places we agree again. When we discuss topics like healthcare, everyone always trots out the "how are we going to pay for it" canard. Some people object to this seemingly reflexive response because it never seems like we have that same response when discussing military spending, going to war, cutting taxes, etc. There is always room for spending. There are tools we can use to account for it. The government budget is not like a household budget. Taxes can be increased. Money can be printed and borrowed. There's always a need to be vigilant and not do these things in excess, and there's always room for discussion around what the threshold should be for what IS excessive and what is NOT excessive, but to boldly proclaim it all to be impossible then drop the mic and walk away is what is truly absurd here. I'm not arguing for pure spending or permanent spending. I'm saying we can shift money from place A to place B, and that we also need to account for future returns. After all, that's what the GOP does when arguing for tax cuts on the rich... I have seen many people (most often conservatives) frame government spending as a pure cost, and I personally feel that's a mistake... a completely unrealistic perspective on how economies operate. Now... This is my opinion, and it's perfectly okay to hold a different one, but I frame these issues instead as investments. What is the expected return? Will this increase jobs? Will this reduce poverty? Will this enhance wellbeing? How will these affects impact revenues and growth? What are the costs of inaction (this last one is especially relevant when rebuilding after hurricanes for not proactively addressing climate change). It's just that this constant and immediate shitting on ideas is so one-sided and so hypocritical from one topic to the next. These calls for detailed payment plans when the topic relates to healthcare or green jobs programs... these defeatist attacks that suggest forcefully that "WE JUST CAN'T DO IT!!1!!2!one!!"... yet at the same time and from the exact same people deafening silence when it comes to giving massive handouts to corporations or adding a few hundred billion for the military or lobbing a few multi-million dollar missiles into the desert overseas somewhere... Nope, not a peep! Nothing. Nada. Zilch... Crickets in an amphitheater. And don't even get me started about when actual payment plans are shared and just get swept aside in strawmen and scaremongering... The core issue here is about what we choose to value. It's the politics that are hard, not the economics, yet it's always the economics used to short-circuit the conversation and prevent us from even talking about these ideas or creatively finding ways to achieve them. Seriously... You're going on about how we cannot afford healthcare, yet today already we pay something like 3x what most other civilized nations do, and we have generally worse outcomes, lower quality care, and we don't even manage to cover everyone. We don't need to invent this from scratch, we just need to look at what's working elsewhere, claim it for our own, and stand up to fight for it in good faith. This is not a problem of budgeting, it's a problem of priorities. Now... AOC is just the newest foil for the right. She's the new bogeyman being used to get people all lathered up and wetting their pants and distracted from reasonable dialogue, but no matter how many times you repeat the word math or call her arrogant or pretend you're taking some arbitrary high-ground... no matter how many times you call her a liar for using poetic license on a single news article and no matter how much you get yourself all worked up into a tizzy and tell us all you're taking your ball and going home... there is just nothing about what she's suggesting that is either impossible or unworkable.
  18. 2 points
    Australia's National Parks and Forestry and community Fire authorities use controlled burning and have never been prevented by "green regulation" from using it. Leading fire experts and former and current heads of fire authorities reject the claims that green regulation preventing burning off is to blame. Blaming environmentalists is a nasty political claim that has no actual substance. The forestry industry has long been antagonistic to those calling for forest protection and regulation that limits their access to State owned forest resources - hating greenies comes with the job. But I think conservative right politics has become especially antagonistic and inflaming those hatreds because those are the loudest voices on climate change, the message is cutting through and that issue is gaining popular support. Australian Greens have no policies that prevent hazard reduction burning - tending more towards promoting indigenous practices of controlled burning. They have never had enough representation to force policies on this. Livestock have been excluded from National Parks because their purpose is for native flora and fauna, not private grazing (a privilege widely abused when and where it was or is permitted); lots of Australians who are not "greenies" fully support that purpose. Reduced opportunities for burning off are more to blame for inadequate hazard reduction burning, as well as poor resourcing of National Park and Forestry management, that have to have teams and equipment on the ground to do it. Record and near record warm winters are making what was previously a relatively predictable and relatively safe activity - hazard reduction burning - unpredictable and dangerous. Fire authorities have always had all the authority needed, to conduct burning off but they also have authority to call a halt to burning off when conditions are making it too dangerous.They decide, not The Australian Greens. My own observation and speculation is that one of the crucial things that is changing with climate change warmer winters is lack of dew; my own observation was that previously, winter burning was often self limiting because cool conditions caused dew to form late in the night or early morning. Fires were lit in the previous afternoon or evening with a reasonable expectation they would go out. With warmer conditions there can be no such expectation; these activities are requiring ever greater vigilance, more people on the ground and more equipment. Around here - in the middle of recent fires - the last few winters would have allowed no more than 1 month of opportunity to fires to burn slowly with low likelihood of escaping containment. That is actually too short a time for large areas with high fuel loads; six weeks can be considered the minimum for a fire to burn out sufficiently to be declared "out" and slow burning trees and tree roots can still restart fires for longer periods than that. When I consider warming of 3C (at best I think) and possibly more than 5C (with the minimum levels of climate action that would be welcomed by Australia's current government) - it is properly terrifying.
  19. 2 points
    Not everything is about your President, guys. Iran has been destabilizing the region for years... yet everyone assumes it is the 'President we love to hate' who is destabilizing the region. Iran has been in a 'proxy' war with the US for years, Using the Hezbollah ( Shia ) political parties in neighboring countries to stir up trouble against Sunni controlled governments and US interests in those countries. Both England and Germany have sided with the US on this act, while Russia and France have condemned it ( China as usual, has been quite non-committal ) Funny how a country like Iran burns off enough natural gas ( byproduct of their oil extraction, called flaring ) to supply a small country, yet, can claim with a straight face, that it needs home-grown nuclear technology for reasons other than warfare.
  20. 2 points
    The gauge groups I mentioned are not specifically the harmonic oscillator. QFT accounts for the quantum harmonic oscillator in its gauge groups but that isn't the full story. https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.hep.phy.cam.ac.uk/~gripaios/gft_lecture_notes.pdf&ved=2ahUKEwi79v_N09TmAhVuHzQIHbErDekQFjAAegQIBhAB&usg=AOvVaw2Tq7K0egwVnGx8aslG3PJE Here is a primer QFT takes a considerable time to learn. https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.damtp.cam.ac.uk/user/tong/qft/qft.pdf&ved=2ahUKEwjw6qeL1tTmAhVXs54KHaCABBkQFjAAegQIBRAB&usg=AOvVaw0XQ8pIIPzIxiwafEUsja8F In order to be observed there must be a quanta of action. The external lines on those Feymann diagrams are observable's. (Operators) The internal lines (propogators ) (often thought of as virtual particles) are not observable. Here is the standard model of particle physics (not including Higgs) that is in another post [math]\mathcal{G}=SU(3)_c\otimes SU(2)_L\otimes U(1)_Y[/math] Color, weak isospin, abelion Hypercharge groups. Couplings in sequence [math]g_s, g, \acute{g}[/math] [math]\mathcal{L}_{gauge}=-\frac{1}{2}Tr{G^{\mu\nu}G_{\mu\nu}}-\frac{1}{2}Tr {W^{\mu\nu}W_{\mu\nu}}-\frac{1}{4}B^{\mu\nu}B_{\mu\nu}[/math] Field strengths in sequence in last G W B tensors for SU(3),SU(2) and U(1) Leads to covariant derivative [math]D_\mu=\partial_\mu+ig_s\frac{\lambda_i}{2}G^i_\mu+ig\frac{\sigma_i}{2}W^i_\mu+igQ_YB_\mu[/math] Corresponds to [math]G_{\mu\nu}=-\frac{i}{g_s}[D_\mu,D_\nu][/math] [math]W_-\frac{I}{g}[D_{\mu}D_{\nu}][/math] [math]B_{\mu\nu}-\frac{I}{\acute{g}}[D_\mu,D_\nu][/math] You can find the Higgs on page two https://www.scienceforums.net/topic/117992-the-lagrangian-equation/ In essence we were trying to validate and reverse engineer the equation in post 1. In order to do that I had to examine each gauge group of the standard model. Given by [math]\mathcal{G}=SU(3)_c\otimes SU(2)_L\otimes U(1)_Y[/math]
  21. 2 points
    No way. You're about a hundred years older than me.
  22. 2 points
    US special forces staged a raid near the Syria/Turkey border and flushed out Abu Bakr al-Baghdadi, who then blew himself up with explosives when trapped. Apparently DNA confirmation of his identity is now possible 'in the field' and much quicker than the usual couple of weeks it takes for criminal cases. Obviously there is a need to be sure, as he has been 'reportedly' killed several times before. D Trump is either trying to draw attention from his escalating problems, or still trying to take wind from B Obama's sails ( the Osama bin-Laden takedown ), as apparently he posted a ( staged ) picture in the Situation Room from the wrong time; he was playing golf during the actual raid. Congratulations to American Special Forces and Intelligence Services. Also, our Allies in the area who supplied the intelligence; you know, those same people D Trump deserted and left to be slaughtered by the Turkish offensive two weeks ago.
  23. 2 points
    Why can't you see who giving you likes? Compared to some of the people on the forum, who actually know about science, my posts contain no substance whatsoever, yet I've got 22. I know there not important, I'm just curious.
  24. 2 points
    I wasn’t totally convinced at first, but I like Warren a lot. I’ve been tracking her for years, especially after the financial crisis and steps she took to fight back against banks in support of families like mine. I also like that her dream job was teaching special needs kids, and that’s what she did until getting fired for being pregnant. I think she’s genuine in her desire to help, understands the system better than most and is smart as hell, capable of getting it done, and isn’t in it just for reasons of avarice. Beyond that, I’m still waffling a bit about who my next choices are, and now that I live in Iowa I take it pretty seriously. Mayor Pete is impressive and smart, and I liked what I heard when I went to go meet him. He’s focused on the right things and surrounds himself with smart people, but I’m just not convinced he’s ready for the top slot (tho Trump has shown anyone can do it). I also met Michael Bennett and quite liked him. Super down to earth and well rounded. He’s a former school administrator and just a smart decent guy. He’s got a great collaborative demeanor, tons of respect across the aisle, and everyone who’s worked with him loves and respects him quite a bit regardless of party, but he’s just not inspiring people and that’s critical. He’s a bit milquetoast, TBH, and that won’t fare well in a cage match with Teflon Don. I was previously interested in Kamala and would love to watch her rhetorically punch Trump in the balls, but I get a sense of inauthenticity and heavy reliance on talking points from her that doesn’t sit well with me. She’s clearly a smart fighter, though, just still have no idea what she truly stands for / what her principles are. I’m a firm no on Beto, Tulsi, de Blasio, and the bulk of the others (can anyone say Mariam Williamson???), but do like Booker... just don’t think he can win. Would prefer him to be selected for a cabinet position addressing racial disparities in criminal justice and gun policy, etc. I’m also watching Andy Yang a bit like I would watch a lab grown experiment in a Petri dish, but to me he’s more of an interesting oddity than a serious contender (sorry, JCM... different strokes for different folks, and all). Anyway, we’re the first people on the planet here in Iowa who get to decide on this, so we can’t adjust our choice based on what other voters have chosen in other states... I can’t wait and see who’s popular or who gets traction, but instead need to be ready to make more of a raw and personal choice. I’ll need to stand in a room with my neighbors and with my kids on a cold winters night in February and choose my person for all to see. to defend my choice / try to convince others to join me and make the same choice when the caucuses occur. I’ll also be there to listen to others and will try to remain open to being convinced by them to move over to their candidate instead... All that said, no matter who wins the primary, I’ll most definitely be voting for that person in the general, whether they were my 1st choice or my 17th. This needs to be an election more about principles than purity. Peace ✌️
  25. 2 points
    The Sun is so hot that most of the gas is ionised. Free electrons and protons are allowed to have (almost ) any energies. When they crash into eachother some fraction of the energy- depending on angles of impact etc, is sent out as em radiation. Also, at those temperatures the "lines" are broadened by doppler shift and at the high pressures involved they are also broadened by collisions. https://en.wikipedia.org/wiki/Spectral_line#Line_broadening_and_shift The overall effect is a mass of overlapping emission bands which approximate (rather well) to a black body spectrum.
  26. 2 points
    I'm a welder. It's a steady income now that I have a family. I failed out of a biochemistry program years ago. The hardest thing I've had to overcome was depression. Hindsight I've learned a lot about the value of education. I'd cut off my arm to go back to school. I have no idea what I would tell myself in the past. And I really think I should know. I didn't make this topic because I wanted to talk about myself. I want to know how smart, successful people came to choose their careers and if anything helped make them into who they are today.
  27. 2 points
    Here is the arxiv article https://arxiv.org/abs/1906.03369 Hrrm how to simplify this. Ok let's give this a shot. In classical physics you have the E and B fields for electromagnetism however in QM those fields are replaced by the probability potentials [math]\phi[/math] and [math]\mathcal{A}[/math] now in regions where the E and B fields are zero you can still have potential via the wavefunction that the [math]\phi[/math] and [math]\mathcal{A}[/math] are non zero This tells us that the QM and QFT subsequently treatments is more fundamental than the classical treatment in that it is more complete in the information of the EM field. In essence the paper helps confirm that the probability wave functions do have a physical and measurable effect through their potentials. For example it's also a key aspect to how a particle wave packet can go through two slits at once.
  28. 2 points
    Someone asked a question the other day that made me realise that there seems to be a parallel between the Heisenberg uncertainty principle (HUP) and Noether's theorem. For example, one conjugate pair of variables in the HUP is energy and time. While in Noether's theorem, the conservation of energy is related to time symmetry. Another conjugate pair is momentum and position. And the conservation of momentum is related to spatial translation symmetry. I assume this is not just a coincidence. So is there a deeper reason? Is Noether's theorem the reason why these are conjugate pairs?
  29. 2 points
    They must spend a fortune on custom-made hand puppets for this type of briefing.
  30. 2 points
    This is the key. Right now, insurance money (which the taxpayer has paid) and tax subsidies (which the taxpayer has paid) are being based on maximum profit like any growth business model. The problem is that healthcare needs to be aimed at caring for people's health in order to be effective. In the US, the focus on profit allows businesses to leech away funds that the taxpayer needs. One example among many is durable medical devices. Businesses are allowed to create monopolistic deals with doctors offices for oxygen, blood, and sleep devices. There's no competition for them with your provider, so you have no choice when they fail to provide their services, or overbill, or send the wrong filters/tubes/parts. They learned this from the cable TV giants, who similarly have no competition within their protected areas. Customer service becomes a big joke (google Apria Healthcare or Comcast customer service and look at the comments!). We definitely need a more European attitude about spending on social requirements (which I feel healthcare is). In the US, we let capitalism build the paths our socialism takes, and wonder why all our money gets leeched away.
  31. 2 points
    Here is what one average person (me) thinks. Trying to make big progress is good! But you reference concepts such as bosons, gravitons, entanglement, spin, black holes, invariant speed of light from currently accepted theories. That means you are working in the framework where those concepts makes sense and are applicable. Things that are inherently incompatible with these concepts will not impress on professionals. Example; faster than light travel and information exchange and anti gravity cannot work in the current theories of relativity and standard model of particles as far as I know. That means that your proposed ideas is not possible within the currently accepted theories and models as pointed out by members more skilled than me. And these theories are supported by loads of evidence. You need to find some way to make progress outside current theories. Something completely new and novel is required by you. Not adjustments or adoptions of concepts in current theories, that is not enough to fundamentally change the basis for current theories.
  32. 2 points
    Pressure, as commonly understood, is not easily related to General Relativity. However, if we think of space-time as a coiled spring, it is easy to understand that if you compress that spring, you increase its energy, and the curvature of space-time around it. An easy to understand excerpt from https://ned.ipac.caltech.edu/level5/Guth/Guth3.html explains the relationship between pressure, energy density, space-time curvature ( gravity ) and expansion/inflation. "THE PRESSURE OF THE FALSE VACUUM can be determined by a simple energy-conservation argument. Imagine a chamber filled with false vacuum, as shown in the diagram below. For simplicity, assume that the chamber is small enough so that gravitational effects can be ignored. Since the energy density of the false vacuum is fixed at some value uf, the energy inside the chamber is U=ufV, where V is the volume. Now suppose the piston is quickly pulled outward, increasing the volume by dV. If any familiar substance were inside the chamber, the energy density would decrease. The false vacuum, however, cannot rapidly lower its energy density, so the energy density remains constant and the total energy increases. Since energy is conserved, the extra energy must be supplied by the agent that pulled on the piston. A force is required, therefore, to pull the piston outward, implying that the false vacuum creates a suction, or negative pressure p. Since the change in energy is dU = ufdV, which must equal the work done, dW = -pdV, the pressure of the false vacuum is given by p = -uf. The pressure is negative, and extremely large. General relativity predicts that the gravitational field which slows the expansion of the universe is proportional to uf + 3p, so the negative pressure of the false vacuum overcomes the positive energy density to produce a net repulsive gravitational field. "
  33. 2 points
    Have we ruled out trolling as the cause of the problem? Anyway, it seems that nearly everything can change- everything except Farid's mind.
  34. 2 points
    Implicit in this response is the suggestion that you've read through every single other thread that has arisen here through the years on the topic of IQ. Given that you haven't, not only are you a troll, but you're a liar... and I know who you are... have you seen you enough times under other usernames.
  35. 2 points
    The Carl Schwarzchild you mention was born in 1873. The quote I gave was from a paper read out to the Royal Society by Henry Cavendish in 1783, on behalf of Michell.
  36. 2 points
    To elaborate what I mentioned above, in order for that to happen the selective sweep must be so strong (or mutation rate so low) that any mutations would have to be strongly selected against. Especially as most mutations will be neutral this is highly unlikely in principle, which makes it very unlikely to exist in practice.
  37. 2 points
    I can understand how it may have seemed hasty without the added perspective of what was happening behind the scenes. As mentioned a few times already, after closing it staff discussed the closure and the member was contacted. We considered reopening the thread if we believed the member was hoping to participate in genuine discussion. They weren’t (as per PM), so it stayed closed. It wasn’t a spur of the moment decision, nor was it irreversible. I’m not sure what else there is to say on the matter. We take these things case by case, and a lot of staff discussions and interactions with members are not made public. That isn’t going to change. SFN is not a conspiracy forum, nor is it a make up whatever BS you want and call it science forum. We give a lot of leeway to people to post and defend their ideas, but we have to draw a line somewhere. If we identify early on that a poster has absolutely no interest in participating in rational discussion, why should we let it continue? That runs completely counterintuitive to the spirit of the forum, and has no place here.
  38. 2 points
    If any reparations are to be made to 'correct' past inequalities/injustices, they would have to be sizeable. 20 dollars apiece and an apology isn't going to do squat to correct the inequalities inherent in the system. That being said, the government does NOT have any of its own money that it can dish out. It is all taxpayer money that the government re-distributes, and any that goes towards reparations either comes at the expense of other programs, or has to be re-payed by our children. So although Dimreepr is being his usual terse self, he makes a valid point and sizeable reparations could hurt others. Why not simply have equal standards going forward, that people are people, not black or white. Only those qualities which directly affect a person's performance/actions is to be considered, not their skin color, sexual orientation, ethnic background, etc. Even what Ten oz did in a previous post, breaking down voting and sports affiliation, while seemingly done to show the inherent inequalities, would be considered racist if done in other areas, such as crime statistics. So you can see the dilemma in trying to have a 'conversation' about reparations; you don't come off as being genuine if you make some areas of discussion off-limits. Some people ( not me, I'll be keeping my distance ) will no doubt want to discuss the role/influence black-on-black violence, and absent fathers, have on the current inequalities. It may start out as a conversation/discussion, but in the current political climate, it would likely degenerate into race wars. Does the US really need that problem also ?
  39. 2 points
    You also need to note that there is a group of people on forums who hold a much more prestigious title than the ones who are mods - the ones who were asked to moderate and refused
  40. 2 points
    I couldn't resist another attempt... how about writing symbols on the back of paper and use back-light? Could work with the right combination of paper thickness, light and ink. Quick experiment, using office paper, ball pen and flashlight from behind paper. Flashlight off: Flashlight on:
  41. 2 points
    ! Moderator Note Please read the rules regarding speculations. Speculation on this site is supposed to be supported by evidence or at least an established theoretical framework. It is not a place for a freewheeling exercise in fact-free nonsense. Locked.
  42. 2 points
    yesterday was my birthday so I took some time to think. think about how much I have learned(mainly from just looking at posts). and how am better than when I started. and part of that was because of you guys(part was just growing up). there is more but I can't find a good way to say it. p.s sorry for being kind of a shiteposter.
  43. 2 points
    AKA 24/7 Reality TV shows. Binge-watching all 21,650 seasons of Man vs Beast. You will LONG for death.
  44. 2 points
    1. Go back and read the posts you made that received multiple neg reps. 2. Don't be that person.
  45. 2 points
    What is a shadow made of? Shadows certainly 'exist' - whatever that means. A shadow is a prime example of zero something. I think the english language offers a good construction. it = a thing is a noun. Nouns can be 'concrete nouns' like an apple or water or well, concrete. Or nouns can be abstract nouns like anger, a shadow, weight and so on.
  46. 2 points
    I didn’t. Now, help me understand how all of this ties to your topic of an independent successfully running for POTUS in 2020. In 2016, the Democrat took 48.2% of the vote, the Republican took 46.1% of the vote, and all the others/independents in total took only 5.7%. Given your laser like focus on vastness and majorities, perhaps you can elaborate a bit on why you think there’s a snowballs chance in hell for an independent victory. Help us unsterstand how you manage to frame this as at all viable given that individual independents in 2016 managed only to secure (as their TOTAL vote percentage) less than the margin by which Clinton won (but still lost the office). Stein and Johnson: 1-3% of the vote. Clinton margin: 2% of the vote. Winner: Trump. J.C.MacSwell: Still wishful thinking and ignoring the facts on the ground by continuing to speak of mythological independents. https://docs.google.com/spreadsheets/d/133Eb4qQmOxNvtesw2hdVns073R68EZx4SfCnP4IGQf8/htmlview?sle=true#gid=19
  47. 2 points
    It all comes down to the fact that the Earth is not a perfect sphere and its axis of rotation is not perpendicular to its orbit around the Sun or the Moon's orbit. Because of the Earth's slight oblate shape, the differential in force acting across it due to the gravity of these two bodies, applies a torque to the Axis in an attempt to align the axis to being perpendicular. But the mass of the Earth has a set angular momentum that it tries to conserve. the end result is the This torque ends up being "deflected" into producing the "wobble" known as precession. If the Earth were a perfect sphere, there would be nothing for the gravity differential to get a "handle on" and we would get no precession.
  48. 2 points
    With this misconception/misinterpretation you're just giving bullets to guns of climate change deniers. It's not so simple. Global warming will melt ice on the North and the South poles. Right. It'll change e.g. underwater sea current in Atlantic. This current is causing warm winters in U.K. Now, if climate change supporter is simplifying global warming to just words like you said, and people see exactly reverse, like it can happen in UK after disappearance of underwater sea current, they will be confused, and say you're talking nonsense about global warming, if they will have severe winters.. Global warming is global change of moderate environment, to the more extreme environment.. Extremity not just in hotness (in some regions), but also extremity of coldness (in some regions).
  49. 2 points
    Beware newspapers need to catch the public's attention. When Angela Merkel said "I can imagine that no car with an Otto or Diesel engine is sold in 2030", in some newspapers it became "Merkel decided to ban Diesel cars in 2030". You believe electric cars are unrealistic... But humans have this ability to make unexpected things possible. For electric cars there is a very strong incentive. Think at LED lamps. Based on the ruinous tiny things just capable of telling "on-off", I thought all plans of LED lighting were foolish. But recently I replaced all my lamps by LED, because they work and are better. Companies have invested billions in that technology. One key is that it suffices when a few people (at the right place!) believe a progress is possible and useful. Never mind if 99.99% of Mankind don't believe it. This is a superiority of a free country, where people can explore new direction and are allowed to fail, over a dictatorship where one single person decides everything and can only try to catch up what was done abroad. Batteries are already good enough to move cars. In California, in Norway, electric cars sell very well. Trucks may be the next big market. Companies invest billions to develop batteries, they will improve. Whether the next ones will use lithium (which isn't expensive nor scarce), zinc or sodium, I don't know. It's impossible to predict 10 years in advance and with limited data. You know, all companies have long thought through before their heavy investments, and they made different decisions. My preferred one is liquid hydrogen at 1atm with vacuum insulation. Decent density, and the tank is only as heavy as the hydrogen. I'd have nothing against adsorption, but it seems to need a high pressure, which makes it less attractive. Aeroplanes will use hydrogen soon, much more so than batteries, and their tanks will spread to cars.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.