Nicely explained and good work👍 Like your vids, so cape them coming ✌
@Ikon0aklast
Жыл бұрын
Dark energy creates negative pressure…is a vacuum…but causes space to expand? 🤯 solid video!! I watch a lot of this content and look forward to more of yours! Sub
@craigsimpson9561
Жыл бұрын
If I may play Devil's Advocate (as opposed to "meta-scientist") it should be worth noting that phlogiston theory was "firmly cemented in science" for decades. It wasn't until researchers thought of bottling air to weigh it that it became increasingly apparent that everyone had been viewing everything backwards. Once oxygen was discovered, it became all too apparent that the air was being "deoxygenated" rather than "rephlogistonated". Once with that final hurdle was cleared, the road was paved for the principle of mass conservation. As you say, a theory is just a theory until it is rigorously proven beyond all doubt. What matters most is the rigour of measurement combined with utter impartiality for the outcome, lest we end up "rephlogistonating" the world of science! ;-)
@cykkm
11 ай бұрын
Perhaps I'm missing your point, or possibly you have a misconception of the real state of affairs with the dark matter. _DM is not a theory._ It's a body of solidly uncontroversial observations, many times confirmed and reconfirmed in many ways, and a few hypotheses, rather handwavy-but we need to hedge the bets and at least start digging in the seemingly most promising directions. The galaxy rotation velocity problem that started it all suggests a field-i.e., spatial distribution-of frictionless massive fluid. It's physical nature doesn't follow from this observation at all. An alternative, the correction to gravity in a very weak field limit, so far has failed to converge with GR, and GR works with such an amazing precision that the bar for any correction is inevitably very high. Chronologically later, with more and more precise CMB measurements, we understood that gravitating _something_ is missing from the Universe right from the start-and a lot of it, a few times the mass of gravitating matter which is accounted for! Is it the same frictionless fluid of massive matter? Well, the current models of the formation of the Universe suggest so, in the sense of its conserved mass. It's not coming from one “snapshot” of the very early Universe and another, taken today. We're looking far back in time when looking far into space, and the missing mass is observed to be missing at all times. But all attempts to detect a new kind of matter particle were unsuccessful, and attempts to modify GR so that it holds together also didn't work so far; besides, the missing mass in the early universe is no longer a source of _very weak_ gravity-the initially promising correction to _Newtonian_ gravity that explained the rotation velocity curves quite well also hit quite a brick wall here; even its initial motivation doesn't apply to the early, dense Universe. All we have is a lot of precise, well-confirmed observations that manifest themselves as frictionless, gravitating, conserved in its quantity _something,_ without which the cosmology falls apart. We tentatively put a patch on the existing models, and called it “dark matter,” making no assumptions of its nature. Is it a kind of matter that stubbornly refuses to interact with known matter? Or does GR require a correction? Or do we maybe need a new, more fundamental theory of spacetime and matter-energy? We don't really know. The first of these fits the models quite well, and is the simplest one-we reach for the Ockham's razor when we've got nothing else-hence the tentative “matter” in the name. But nobody buys it for the real McCoy before it's in fact detected, and then detected again in a different experiment or observation. This is where the physics acceptance bar is situated-much higher that even postulating that dark matter is in fact matter, albeit everything points at this being the most likely in the end. TL;DR, we don't need to be reminded of the phlogiston; this lesson is naturally incorporated into the very method of science as we do it today. Besides, the phlogiston is rather an odd one out-a phenomenological theory that didn't predict anything at all. The luminiferous ether was a much better example theory; it implied something that could be tested experimentally. And no, the M.-M. negative result didn't kill it on the spot, _one_ observation is usually unconvincing. Einstein's radical theory, initially that of flat, then of curved spacetime that disposed of time as the absolute and gravity as a force altogether-with its horrible instantaneous action through the void that was hated (surprise, surprise) by the very Netwon who had put it together!-took many years, one funeral at a time, to absorb.
@craigsimpson9561
11 ай бұрын
@@cykkm Thankyou for demonstrating my point so precisely! You are correct to state "All we have is a lot of precise, well-confirmed observations that manifest" and "Is it a kind of matter that stubbornly refuses to interact with known matter? Or does GR require a correction? Or do we maybe need a new, more fundamental theory of spacetime and matter-energy? We don't really know. " Indeed, not only does your second paragraph support (and even endorse) my point, it rather undermines the bold assertions of your first paragraph! This is not a competition between MOND and CDM, like some sort of football match! This is an active area of research, and one which is presently without a theory sufficient to explain (or reliably predict) the evidence which has been so diligently observed. "Best fit" is a euphemism for "close enough", which is hardly five-sigma level certainty! Now that we agree that all we have *are* precise and well-confirmed observations , we can agree that Lambda CDM is not only just a theory, but either an incomplete or incorrect theory, given that it does nothing to explain what CDM actually *is*. In my experience, "Ockham's Razor" is a euphemism for "Confirmation Bias" utilised by people so enamoured by a thought that they dig deep in denial. TL;DR, Whenever I read claims such as "DM is not a theory", it reminds me that we all need to "be reminded of the phlogiston", since so many seem to have failed to learn the lesson, as so abundantly frequently demonstrate with their confrontational and sanctimonious attitudes. We are all human, all capable of error and delusion, and must remain vigilant to bias at all times, lest we become detached from the very reality which we aspire to observe. Most importantly of all, we must never permit our bias to inflate our self-worth to the point where we denigrate other opinions and that which we do not understand. Science is not a football match!
@cykkm
11 ай бұрын
@@craigsimpson9561 “Indeed, not only does your second paragraph support (and even endorse) my point, it rather undermines the bold assertions of your first paragraph!” - You're clearly not stating any point beyond vacuously true statements. I'm entirely unaware of your views; I expounded my own. And “bold assertion” is judgemental; please don't put words into my mouth. I only interpret where we approximately are, with good intentions. Don't be confrontational. “This is not a competition between MOND and CDM” - Of course not, but there's a but… I don't see them as naturally compatible; in the extreme, it's one or the other. Notably, Hossenfelder published in a couple past years on her attempts to marry them. Her main idea was a phase transition in the DM field from CDM to MOND regime. My understanding is that she dropped it on the floor by now, albeit starting quite enthusiastically, and I'm unaware of any other work developing on this idea. “"Best fit" is a euphemism for "close enough", which is hardly five-sigma…” - best fit is not an euphemism. It really stands for what's on the package; the sigmas work both ways. A good fit supports a model, a lack of such prompts questioning both data extraction methods and the model. I hope it's not necessary to remind that a model doesn't imply or necessarily produces a theory. Again, I don't see what's prompting your negative attitude. Bias is never helpful, be it toward a preferred model, or toward nihilism, all the same. “we can agree that Lambda CDM is not only just a theory, but either an incomplete or incorrect theory, given that it does nothing to explain what CDM actually *is*. ” - No, we cannot agree on that. First, a theory is the highest level construct in science, so that “just a theory,“ even less the “not only just a theory but” have no meaning; “just a theory” is an oxymoron, a self-contradictory description given commonly understood context. A theory is a more lax concept in astrophysics, which is an observational science. ΛCDM _in a narrow sense, dark energy + cold dark matter, doesn't feel a predictive theory to me yet: it's way too phenomenological to be one at this stage. In the wide sense, which ΛCDM is also used in (“the whole modern cosmology”), it includes the Big Bang and a kitchen sink. To me, it's a sloppy use of the term. The Big Bang _is_ a theory. Second, all our theories are incomplete or incorrect, or both. Your assertion is vacuously true. Science is “just” currently the best construct, philosophical and social, to faithfully capture Nature's ways in theoretical frameworks. Idealistically, the absolute majority of people working in science believe that such a truthful capture is _in principle_ possible, i.e. that Nature is comprehensible to the mind in her entirety. Practically, the truth contents of this postulate does not matter, as it's ; it serves as an underlying philosophical postulate. It would perhaps be impossible to dedicate one's life to science without such a belief: while science is a societal, communal, co-operative effort, academia, the societal formation which is _doing_ the majority of science, is individualistic and extremely competitive. It doesn't pay very good either, doesn't confer a celebrity status or puts one in a position of power-arguably, the three most important human lustful longings-so that it's hard to grasp how one may be attracted to academia without a belief in science and a genuine desire of discovering Nature's secrets. What I'm reading aloud here is common knowledge; I'm explicitly refraining of sharing my personal opinions on academia as a social phenomenon, as it wouldn't contribute to the discussion, whose focus is chiefly on science itself. I'm expecting the same of you, please. Whether I'm astonished by the wonderful construction of the Solar System or enraged by its faulty construction full of punch points, the Solar System doesn't care and is hardly going to take my feedback and improve. The same applies to the society: it evolves rather than being made, it's a complex system in the system theory sense, and may only be accepted as is. Third, the question of what something “really” is, in this distilled form, is ill-posed and unanswerable. We construct theories to capture our knowledge of Nature; the theories carve out objects out of reality, idealised to lesser or greater degree, and operate with these objects. Objects of theories don't make sense outside of these theories. There is no force of gravity in GR; there's no spacetime in Newtonian mechanics. Sometimes there is an overlap; other times a complete disjunction, as is in this example. Fourth, theories rarely if ever describe what their objects _are,_ much less what they _“really” are._ When I hear, mostly from laypeople curious of science, that they have a trouble believing that dark energy is behaving like “negative mass“ (entirely wrong but often oversimplified down to this; FWIW, GR is compatible with negative mass, albeit we never observed it-but so it is with black holes, initially dismissed as a non-physical artifact of the theory's maths) or “repulsive gravity“ (better, that more or less works), I invariably ask: “oh, so you have no problem with the ‘normal,’ positive energy? Can you explain what it is?” This really makes people think. Energy is an interesting scalar quantity, a good numeric variable in many theories, very useful in describing many observed phenomena, conserved in most theories and models, thus giving rise to useful symmetries, simplifying the mathematical description... Is it what energy *is*-a _useful real number?_ Yes, people wave their hands, and try to explain “but it really is… but of course it's very intuitive! The energy is just energy! Motion, schmotion, heat, schmeat...” Another philosophical question is about “the nature of time.” To me, myself being steeped in GR, time is that quantity whose interval my own clock measures. Period. It has no “nature,” but I can measure an interval of my local proper time, which is different from yours. I can tell you how my watch or atomic clock works, but that won't take you closer to an answer to the question “what is time?” I know that, philosophically, this is not a universally shared point of view. Smolin, for one, believes in the reality of time, in some sense. The fact that I can understand the physics he produces, and, although I don't recall him consuming mine, that's certainly not an impossibility too, is a very strong indication that this fundamental disagreement lies outside the domain of physics proper. Now, do you know what is the _nature_ of energy, what it “really is?” If you believe you do, good; people have a wide range of beliefs. If not, it's a quantity. An abstraction, a number. You can't point to it. GR is perfectly compatible with energy density inherent to spacetime, and exerting pressure where it's present, which is everywhere. The anecdote that Einstein “just inserted a constant into the EFE” is at best half-true. EFE-like equations can be derived in the weak field limit from the classical gravitational potential φ(R); Λ later arises as a constant of integration, not fixed by initial condition, i.e. as a free parameter. I have some reservations, however: I'm not certain if he had derived it this way. “In my experience, "Ockham's Razor" is a euphemism for "Confirmation Bias" utilised by people so enamoured…” - Fifth, and the last. In _my_ experience, the Good Old Will's razor a sensible tool to decide on what problem to spend the next 5 or 10 years of your only life, when everything is so unclear. There are too many paths open, and new data pours in at a waterfall rate. You seem to refer to quite a negative personal experience. While I hear you, personal grudges are out of scope. Bad science happens. That's indeed not the news for you. “so many seem to have failed to learn the lesson, as so abundantly frequently demonstrate with their confrontational and sanctimonious attitudes.” - The first half is vacuously true. Some have, some haven't. Many? “Abundantly” demonstrate? How many is many, and how much is abundant? As many as there are grains of sand in a heap? In the second, you seem to allude to your personal beef within academia. This is clearly out of scope. What I distill is that you believe science as a social process is in a big trouble, but the depth of your argumentation is entirely unconvincing. “We are all human, all capable of error and delusion, and must remain vigilant to bias at all times, lest we become detached from the very reality which we aspire to observe. Most importantly of all, we must never permit our bias to inflate our self-worth to the point where we denigrate other opinions and that which we do not understand.” - Sounds line a Universal Declaration of Ideal Scientist. True, but kinda implicit. You won't change the human condition or academia by repeating declarations like this. Precisely, you won't change it by the use of any device. “Science is not a football match!” - Ummm.... uhh… meh… okay. That was supposed to be an immensely profound observation, I suppose. You've utterly failed to coney your thought, and at this point I assume that the reason is that you don't have a cohesive one. I hear only blanket banalities and echoes of personal grudges. I don't believe that this discussion would be of any use to either of us if dragged on, and have to bow out. Thank you for your time.
@craigsimpson9561
11 ай бұрын
@@cykkm Narcissism is learning disorder. How can you learn something when you "already know everything"? No wonder you were so upset when I dared to hold an opinion other than your own. No wonder you felt the need to insult me until I conformed to your bias. What right do I have to hold an opinion which conflicts with your personal beliefs, after all? Anyway, let me see if I have this straight: you start off by calling me ignorant, lecture me based upon your presumption of said ignorance, and have the nerve to tell me "don't be confrontational" and "don't put words in my mouth"? Why are you so blind to your own hypocrisy? Is it your arrogance, or your confirmation bias acting out of fear of being wrong (which must seem impossible to you, as you are incapable of error, right)? My original point still stands: arrogance, hubris, narcissism, hypocrisy, irrational attachment - none of this is good science, and anyone guilty of such sins cannot be an impartial observer! If that makes no sense to you, then I can't help you. Once again, you have demonstrated my point perfectly, despite your claims that you are unaware of what I was actually saying. Self-delusion does not facilitate impartial observation. Regardless, since you seem to be intent on personal attacks and deliberately obstinate rather than a polite and open-minded discussion, I now know that there is no point in reasoning with you. Remember, you're the one who started his comment by insulting me in a confrontational manner, so to cry foul at my response to such needless and baseless attacks (all because I dared to question your pet theory and make you feel uneasy to the point of excessive justification of your confirmation bias) is rather rich, wouldn't you say? I know you are too ashamed to reply, so I will presume your apology, and therefore, I shall forgive you.
@TalkingGIJoe
Жыл бұрын
there is no such thing as dark energy or dark matter... everything we need is there, we just lack understanding.
@OVAstronomy
Жыл бұрын
If only people would watch the video or at least read the description before commenting this...
@craigsimpson9561
Жыл бұрын
"There is no dark side of the moon! Matter of fact, it's all dark." -- Professor Pink Floyd Seriously, though, the reason it's called "dark" is precisely because it is unobserved and thereby unknown. In other words, your comment actually reads: "there is no such thing as unknown energy or unknown matter... everything we need is there, we just lack understanding." Generally, most people agree that what we are searching for is something unknown, regardless of its actual state...
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