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Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 10:52pm On Oct 30, 2021 |
Workch:Not at all. |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by Workch: 11:15pm On Oct 30, 2021 |
A001:A lot of people misunderstand the double slit experiment. |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 11:18pm On Oct 30, 2021 |
Workch:How so? |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by Workch: 11:21pm On Oct 30, 2021 |
A001:many people think that the Doble slit experiment infers that two people can look at the same thing and see something different. That's not what double slit experiment actually means |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 11:23pm On Oct 30, 2021 |
Workch:True. |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 7:56am On Oct 31, 2021 |
Ask Ethan: What should everyone know about quantum mechanics? Quantum physics isn't quite magic, but it requires an entirely novel set of rules to make sense of the quantum universe. KEY TAKEAWAYS 1. The laws of physics always apply to every object in the universe, but on quantum scales, the behavior is far from intuitive. 2. At a fundamentally quantum level, everything is both wave and particle, and outcomes can only be predicted probabilistically. 3. Still, it's the most successful, most powerful framework ever developed to describe reality, and everything in existence obeys its rules. The most powerful idea in all of science is this: The universe, for all its complexity, can be reduced to its simplest, most fundamental components. If you can determine the underlying rules, laws, and theories that govern your reality, then as long as you can specify what your system is like at any moment in time, you can use your understanding of those laws to predict what things will be like both in the far future as well as the distant past. The quest to unlock the secrets of the universe is fundamentally about rising to this challenge: figuring out what makes up the universe, determining how those entities interact and evolve, and then writing down and solving the equations that allow you to predict outcomes that you have not yet measured for yourself. In this regard, the universe makes a tremendous amount of sense, at least in concept. But when we start talking about what, precisely, it is that composes the universe, and how the laws of nature actually work in practice, a lot of people bristle when faced with this counterintuitive picture of reality: quantum mechanics. That’s the subject of this week’s Ask Ethan, where Rajasekaran Rajagopalan writes in to inquire: “Can you please provide a very detailed article on quantum mechanics, which even a… student can understand?” Let’s assume you’ve heard about quantum physics before, but don’t quite know what it is just yet. Here’s a way that everyone can — at least, to the limits that anyone can — make sense of our quantum reality. Before there was quantum mechanics, we had a series of assumptions about the way the universe worked. We assumed that everything that exists was made out of matter, and that at some point, you’d reach a fundamental building block of matter that could be divided no further. In fact, the very word “atom” comes from the Greek ἄτομος, which literally means “uncuttable,” or as we commonly think about it, indivisible. These uncuttable, fundamental constituents of matter all exerted forces on one another, like the gravitational or electromagnetic force, and the confluence of these indivisible particles pushing and pulling on one another is what was at the core of our physical reality. The laws of gravitation and electromagnetism, however, are completely deterministic. If you describe a system of masses and/or electric charges, and specify their positions and motions at any moment in time, those laws will allow you to calculate — to arbitrary precision — what the positions, motions, and distributions of each and every particle was and will be at any other moment in time. From planetary motion to bouncing balls to the settling of dust grains, the same rules, laws, and fundamental constituents of the universe accurately described it all. Until, that is, we discovered that there was more to the universe than these classical laws. 1.) You can’t know everything, exactly, all at once. If there’s one defining characteristic that separates the rules of quantum physics from their classical counterparts, it’s this: you cannot measure certain quantities to arbitrary precisions, and the better you measure them, the more inherently uncertain other, corresponding properties become. Measure a particle’s position to a very high precision, and its momentum becomes less well-known. Measure the angular momentum (or spin) of a particle in one direction, and you destroy information about its angular momentum (or spin) in the other two directions. Measure the lifetime of an unstable particle, and the less time it lives for, the more inherently uncertain the particle’s rest mass will be. These are just a few examples of the weirdness of quantum physics, but they’re sufficient to illustrate the impossibility of knowing everything you can imagine knowing about a system all at once. Nature fundamentally limits what’s simultaneously knowable about any physical system, and the more precisely you try and pin down any one of a large set of properties, the more inherently uncertain a set of related properties becomes. 2.) Only a probability distribution of outcomes can be calculated: not an explicit, unambiguous, single prediction. Not only is it impossible to know all of the properties, simultaneously, that define a physical system, but the laws of quantum mechanics themselves are fundamentally indeterminate. In the classical universe, if you throw a pebble through a narrow slit in a wall, you can predict where and when it will hit the ground on the other side. But in the quantum universe, if you do the same experiment but use a quantum particle instead — whether a photon, and electron, or something even more complicated — you can only describe the possible set of outcomes that will occur. Quantum physics allows you to predict what the relative probabilities of each of those outcomes will be, and it allows you do to it for as complicated of a quantum system as your computational power can handle. Still, the notion that you can set up your system at one point in time, know everything that’s possible to know about it, and then predict precisely how that system will have evolved at some arbitrary point in the future is no longer true in quantum mechanics. You can describe what the likelihood of all the possible outcomes will be, but for any single particle in particular, there’s only one way to determine its properties at a specific moment in time: by measuring them. 3.) Many things, in quantum mechanics, will be discrete, rather than continuous. This gets to what many consider the heart of quantum mechanics: the “quantum” part of things. If you ask the question “how much” in quantum physics, you’ll find that there are only certain quantities that are allowed. Particles can only come in certain electric charges: in increments of one-third the charge of an electron. Particles that bind together form bound states — like atoms — and atoms can only have explicit sets of energy levels. Light is made up of individual particles, photons, and each photon only has a specific, finite amount of energy inherent to it. In all of these cases, there’s some fundamental value associated with the lowest (non-zero) state, and then all other states can only exist as some sort of integer (or fractional integer) multiple of that lowest-valued state. From the excited states of atomic nuclei to the energies released when electrons fall into their “hole” in LED devices to the transitions that govern atomic clocks, some aspects of reality are truly granular, and cannot be described by continuous changes from one state to another. 4.) Quantum systems exhibit both wave-like and particle-like behaviors. And which one you get — get this — depends on if or how you measure the system. The most famous example of this is the double slit experiment: passing a single quantum particle, one-at-a-time, through a set of two closely-spaced slits. Now, here’s where things get weird. If you don’t measure which particle goes through which slit, the pattern you’ll observe on the screen behind the slit will show interference, where each particle appears to be interfering with itself along the journey. The pattern revealed by many such particles shows interference, a purely quantum phenomenon. If you do measure which slit each particle goes through — particle 1 goes through slit 2, particle 2 goes through slit 2, particle 3 goes through slit 1, etc. — there is no interference pattern anymore. In fact, you simply get two “lumps” of particles, one each corresponding to the particles that went through each of the slits. It’s almost as if everything exhibits wave-like behavior, with its probability spreading out over space and through time, unless an interaction forces it to be particle-like. But depending on which experiment you perform and how you perform it, quantum systems exhibit properties that are both wave-like and particle-like. 5.) The act of measuring a quantum system fundamentally changes the outcome of that system. According to the rules of quantum mechanics, a quantum object is allowed to exist in multiple states all at once. If you have an electron passing through a double slit, part of that electron must be passing through both slits, simultaneously, in order to produce the interference pattern. If you have an electron in a conduction band in a solid, its energy levels are quantized, but its possible positions are continuous. Same story, believe it or not, for an electron in an atom: we can know its energy level, but asking “where is the electron” is something can only answer probabilistically. So you get an idea. You say, “okay, I’m going to cause a quantum interaction somehow, either by colliding it with another quantum or passing it through a magnetic field or something like that,” and now you have a measurement. You know where the electron is at the moment of that collision, but here’s the kicker: by making that measurement, you have now changed the outcome of your system. You’ve pinned down the object’s position, you’ve added energy to it, and that causes a change in momentum. Measurements don’t just “determine” a quantum state, but create an irreversible change in the quantum state of the system itself. 6.) Entanglement can be measured, but superpositions cannot. Here’s a puzzling feature of the quantum universe: you can have a system that’s simultaneously in more than one state at once. Schrodinger’s cat can be alive and dead at once; two water waves colliding at your location can cause you to either rise or fall; a quantum bit of information isn’t just a 0 or a 1, but rather can be some percentage “0” and some percentage “1” at the same time. However, there’s no way to measure a superposition; when you make a measurement, you only get one state out per measurement. Open the box: the cat is dead. Observe the object in the water: it will rise or fall. Measure your quantum bit: get a 0 or a 1, never both. But whereas superposition is different effects or particles or quantum states all superimposed atop one another, entanglement is different: it’s a correlation between two or more different parts of the same system. Entanglement can extend to regions both within and outside of one another’s light-cones, and basically states that properties are correlated between two distinct particles. If I have two entangled photons, and I wanted to guess the “spin” of each one, I’d have 50/50 odds. But if I measured the spin of one, I would know the other’s spin to more like 75/25 odds: much better than 50/50. There isn’t any information getting exchanged faster than light, but beating 50/50 odds in a set of measurements is a surefire way to show that quantum entanglement is real, and affect the information content of the universe. 7.) There are many ways to “interpret” quantum physics, but our interpretations are not reality. This is, at least in my opinion, the trickiest part of the whole endeavor. It’s one thing to be able to write down equations that describe the universe and agree with experiments. It’s quite another thing to accurately describe just exactly what’s happening in a measurement-independent way. Can you? I would argue that this is a fool’s errand. Physics is, at its core, about what you can predict, observe, and measure in this universe. Yet when you make a measurement, what is it that’s occurring? And what does that means about reality? Is reality: 1. a series of quantum wavefunctions that instantaneously “collapse” upon making a measurement? 2. an infinite ensemble of quantum waves, were measurement “selects” one of those ensemble members? 3. a superposition of forwards-moving and backwards-moving potentials that meet up, now, in some sort of “quantum handshake?” 4. an infinite number of possible worlds, where each world corresponds to one outcome, and yet our universe will only ever walk down one of those paths? If you believe this line of thought is useful, you’ll answer, “who knows; let’s try to find out.” But if you’re like me, you’ll think this line of thought offers no knowledge and is a dead end. Unless you can find an experimental benefit of one interpretation over another — unless you can test them against each other in some sort of laboratory setting — all you’re doing in choosing an interpretation is presenting your own human biases. If it isn’t the evidence doing the deciding, it’s very hard to argue that there’s any scientific merit to your endeavor at all. If you were to only teach someone the classical laws of physics that we thought governed the universe as recently as the 19th century, they would be utterly astounded by the implications of quantum mechanics. There is no such thing as a “true reality” that’s independent of the observer; in fact, the very act of making a measurement alters your system irrevocably. Additionally, nature itself is inherently uncertain, with quantum fluctuations being responsible for everything from the radioactive decay of atoms to the initial seeds of structure that allow the universe to grow up and form stars, galaxies, and eventually, human beings. The quantum nature of the universe is written on the face of every object that now exists within it. And yet, it teaches us a humbling point of view: that unless we make a measurement that reveals or determines a specific quantum property of our reality, that property will remain indeterminate until such a time arises. If you take a course on quantum mechanics at the college level, you’ll likely learn how to calculate probability distributions of possible outcomes, but it’s only by making a measurement that you determine which specific outcome occurs in your reality. As unintuitive as quantum mechanics is, experiment after experiment continues to prove it correct. While many still dream of a completely predictable universe, quantum mechanics, not our ideological preferences, most accurately describes the reality we all inhabit. Source: https://bigthink.com/starts-with-a-bang/basics-quantum-mechanics/ 1 Like 1 Share |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 8:14am On Nov 03, 2021 |
Can you see the Sun? What we see isn't actually what exists. Most people would dismiss this question as being obvious. Everyone can see the sun, right? Actually, the answer is no. We can't see the actual sun. There are 3 layers separating the actual sun and what we actually see. Firstly, the sun is too bright. We are actually blinded by it's brightness. We need special light filters to limit the amount of light reaching our eyes, to actually see anything. This is the result. The second factor is time. Light takes over 8 minutes to travel from the sun to the earth. What we see, is an image from the past. It's not the sun as it currently is. It's like a picture. A picture created by our mind. This brings us to the third layer. It's called indirect realism. You see, the way vision works is that our mind creates a picture based on the light currently striking our eyes. This is how we see things. We never see the actual thing, but only the mind model. Strangely, this is something which some people grasp very easily, while it makes no sense to others. I have yet to find a satisfactory explanation why some people don't get it. What this means is that some people insist that we can see the actual sun, while those who understand indirect realism know that we only see a representation of the sun. A simulation of reality. Source: Quora 1 Like
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Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 1:00pm On Nov 03, 2021 |
This is an interesting group to join: https://www./UnifyQMwithGR/?ref=share
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Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 3:01pm On Nov 03, 2021 |
Does modern cosmology prove the existence of God? The Kalam cosmological argument asserts that everything that exists has a cause, and what caused the Universe? It's got to be God. The Kalam cosmological argument attempts to argue, based on logic and the Universe itself, that God must exist and must have created it. However, in order to be a compelling argument, there must not be any loopholes in any of the premises, assumptions, or steps in the argument. Based on what we currently know, a Universe arising from a creator is definitely possible but isn't necessarily mandatory. We know that everything in the Universe, as it exists today, arose from some pre-existing state that was different from how it is at present. Billions of years ago, there were no humans and no planet Earth, as our solar system, along with the ingredients necessary for life, first needed to form. The atoms and molecules essential to Earth also needed a cosmic origin: from the lives and deaths of stars, stellar corpses, and their constituent particles. The very stars themselves needed to form from the primeval atoms left over from the Big Bang. At every step, as we trace our cosmic history back farther and farther, we find that everything that exists or existed had a cause that brought about its existence. Can we apply this logical structure to the Universe itself? Since the late 1970s, philosophers and religious scholars — along with a few scientists who also dabble in those arenas — have asserted that we can. Known as the Kalam cosmological argument, it asserts that 1, whatever begins to exist has a cause, 2, the Universe began to exist, 3, and therefore the Universe has a cause to its existence. So what, then, is the cause of the Universe’s existence? The answer must be God. That’s the crux of the argument that modern cosmology proves the existence of God. But how well do the premises hold up to scientific scrutiny? Has science proved them, or are other options possible or even likely? The answer lies neither in logic nor theological philosophy, but in our scientific knowledge of the Universe itself. Does everything that begins to exist, or comes into existence from a state of non-existence, have a cause? If you think about it rationally, it makes intuitive sense that something cannot come from nothing. After all, the idea that anything can come from nothing sounds absurd; if it could, it would completely undercut the notion of cause and effect that we so thoroughly experience in our day-to-day lives. The idea of creation ex nihilo, or from nothing, violates our very ideas of common sense. But our day-to-day experiences are not the sum total of all that there is to the Universe. There are plenty of physical, measurable phenomena that do appear to violate these notions of cause and effect, with the most famous examples occurring in the quantum Universe. As a simple example, we can look at a single radioactive atom. If you had a large number of these atoms, you could predict how much time would need to pass for half of them to decay: that’s the definition of a half-life. For any single atom, however, if you ask, “When will this atom decay?” or, “What will cause this atom to finally decay?” there is no cause-and-effect answer. There are ways you can force an atom to split apart: you can get the same effect with a cause. If you were to fire a particle at the atomic nucleus in question, for example, you could trigger its splitting apart and releasing energy. But radioactive decay forces us to reckon with this uncomfortable fact: The same effect that we can achieve with an instigating cause can also be achieved, naturally, without any such instigating cause at all. In other words, there is no cause for the phenomenon of when this atom will decay. It is as though the Universe has some sort of random, acausal nature to it that renders certain phenomena fundamentally indeterminate and unknowable. In fact, there are many other quantum phenomena that display this same type of randomness, including entangled spins, the rest masses of unstable particles, the position of a particle that’s passed through a double slit, and so on. In fact, there are many interpretations of quantum mechanics — paramount among them the Copenhagen Interpretation — where acausality is a central feature, not a bug, of nature. You might argue, and some do, that the Copenhagen Interpretation isn’t the only way to make sense of the Universe and that there are other interpretations of quantum mechanics that are completely deterministic. While this is true, it’s also not a compelling argument; the viable interpretations of quantum mechanics are all observationally indistinguishable from one another, meaning they all have an equal claim to validity. There are also many phenomena in the Universe that cannot be explained without ideas like: 1. virtual particles, 2. fluctuations of (unmeasurable) quantum fields, 3. and a measurement device that forces an “interaction” to occur. We see evidence of this in deep inelastic scattering experiments that probe the internal structure of protons; we predict that it needs to occur in order to explain black hole decay and Hawking radiation. To assert that “whatever begins to exist must have a cause” ignores the many, many examples from our quantum reality where — to put it generously — such a statement has not been robustly established. It may be possible that this is the case, but it is anything but certain. Did the Universe begin to exist? This one is, believe it or not, even more dubious than the prior assertion. Whereas we can imagine that there is some fundamentally deterministic, non-random, cause-and-effect reality underlying what we observe as the bizarre and counterintuitive quantum world, it is very difficult to conclude that the Universe itself must have begun to exist at some point. “But what about the Big Bang?” That’s what they all say, right? Isn’t it true that our Universe began with a hot Big Bang some 13.8 billion years ago? Kind of. Yes, it is definitely true that we can trace the history of our Universe back to an early, hot, dense, uniform, rapidly expanding state. It is true that we call that state the hot Big Bang. But what’s not true, and has been known to be not true for some 40+ years, is the notion that the Big Bang is the beginning of space, time, energy, the laws of physics, and everything that we know and experience. The Big Bang wasn’t the beginning but was rather preceded by a completely different state known as cosmic inflation. There is an overwhelming set of evidence for this, which includes: 1, the spectrum of density imperfections that the Universe exhibited at the onset of the hot Big Bang, 2, the existence of those overdense and underdense regions on super-horizon cosmic scales, 3, the fact that the Universe exhibited completely adiabatic, and no isocurvature, fluctuations at the earliest times, 4, and the fact that there is an upper limit to the temperatures achieved in the early Universe that is well below the scale where the laws of physics break down. Cosmic inflation corresponds to a phase of the Universe where it was not filled with matter and radiation, but rather it had a large, positive energy inherent to the fabric of space itself. Instead of getting less dense as the Universe expands, an inflating Universe maintains a constant energy density for as long as inflation persists. That means instead of expanding and cooling and slowing in its expansion, which the Universe has been doing since the start of the hot Big Bang, the Universe was, prior to that, expanding exponentially: rapidly, relentlessly, and at an unchanging rate. This represents a tremendous change to our picture of what the beginning of things looked like. Whereas a Universe filled with matter or radiation will lead back to a singularity, an inflating spacetime cannot. Not just “may not” but cannot lead to a singularity. Remember, fundamentally, what it means to be an exponential in mathematics: after a certain amount of time, whatever you have will double. Then, when that same amount of time passes again, it doubles again, and so on and so on, without bound. That same logic can be applied to the past: that same amount of time ago, whatever we had was half of what we had now. Take another, equivalent timestep backward, and it is halved once again. But no matter how many times you halve and halve and halve whatever you had initially, it will never reach zero. That’s what inflation teaches us: our Universe, for as long as inflation went on, can only get smaller but can never reach a size of zero or a time that can be identified as the beginning. In the context of General Relativity and theoretical physics, we say that this means the Universe is past-timelike incomplete. Unfortunately for us, in scientific terms, we can only measure and observe what the Universe gives us as measurable and observable quantities. For all the successes of cosmic inflation, it does something that we can only consider unfortunate: by its nature, it wipes out any information from the Universe that existed prior to inflation. Not only that, but it eliminates any such information that arose prior to the final tiny fraction-of-a-second just before the end of inflation, which preceded and set up the hot Big Bang. To assert that “the Universe began to exist” is completely unsupported, both observationally and theoretically. It’s true that, about 20 years ago, there was a theorem published — the Borde-Guth-Vilenkin theorem — that demonstrated that a Universe that always expands cannot have done so infinitely to the past. (It’s another way of expressing past-timelike incompleteness.) However, there is nothing that demands that the inflating Universe be preceded by a phase that was also expanding. There are numerous loopholes in this theorem as well: if you reverse the arrow of time, the theorem fails; if you replace the law of gravity with a specific set of quantum gravitational phenomena, the theorem fails; if you construct an eternally inflating steady-state Universe, the theorem fails. Again, as before, a “Universe that came into existence from non-existence” is a possibility, but it is neither proven nor does it negate the other viable possibilities. Therefore, the Universe has a cause, and that cause is God? By now, we have certainly established that the first two premises of the Kalam cosmological argument are, at best, unproven. If we assume that they are, nevertheless, true, does that establish that God is the cause of our Universe’s existence? That is only defensible if you define God as “that which caused the Universe to come into existence from a state of non-existence.” Here are some examples that show why this is absurd. When we simulate a two-dimensional Universe on a computer, did we bring that Universe into existence, and are we, therefore, the God(s) of that Universe? If the Universe’s inflationary state arose from a pre-existing state, then is the state that gave rise to inflation the God of our Universe? And if there is a random quantum fluctuation that caused inflation to end and the hot Big Bang — the Universe as we know it — to begin, is that random process equivalent to God? Although there would likely be some who argue in the affirmative, that hardly sounds like the all-powerful, omniscient, omnipotent being that we normally envision when we talk about God. If the first two premises are true, and they have not been established or proven to be true, then all we can say is that the Universe has a cause; not that that cause is God. The most important takeaway, however, is this: in any scientific endeavor, you absolutely cannot begin from the conclusion you hope to reach and work backward from there. That is antithetical to any knowledge-seeking enterprise to assume the answer ahead of time. You have to formulate your assertions in such a way that they can be scrutinized, tested, and either validated or falsified. In particular, you cannot posit an unprovable assertion and then claim you have “proved” the existence of something by deductive reasoning. If you cannot prove the premise, all logical reasoning predicated upon that premise is unsubstantiated. It remains possible that the Universe does, at all levels, obey the intuitive rule of cause-and-effect, although the possibility of a fundamentally acausal, indeterminate, random Universe remains in play (and, arguably, preferred) as well. It is possible that the Universe did have a beginning to its existence, although that has by no means been established beyond any sort of reasonable scientific doubt. And if both of those things are true, then the Universe’s existence would have a cause, and that cause may be (but isn’t necessarily) something we can identify with God. However, possible does not equate to proof. Unless we can firmly establish many things that have yet to be demonstrated, the Kalam cosmological argument will only convince those who already agree with its unproven conclusions. Source: https://bigthink.com/starts-with-a-bang/modern-cosmology-god/ |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 6:18pm On Nov 03, 2021 |
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Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 8:54pm On Nov 03, 2021 |
The most detailed image of the sun. Nature is amazingly beautiful! Image Credit: NASA 1 Like
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Re: All About Science: Key Facts, Researches, And Discoveries In Physics by Workch: 9:27pm On Nov 03, 2021 |
A001:must have been taken by Parker solar probe |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 9:29pm On Nov 03, 2021 |
Workch:I think so. |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by Workch: 9:35pm On Nov 03, 2021 |
A001:Most definitely, that’s the closes object we have to the sun. |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 9:55pm On Nov 03, 2021 |
Workch:Okay. |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 10:26pm On Nov 03, 2021 |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by Nobody: 12:41am On Nov 04, 2021 |
A001: Do you think what is real has a beginning? |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 4:47am On Nov 04, 2021 |
Crystyano:Yes. But I don't think existence has a beginning or an end. A person or thing has always existed and will always exist in one form or the other. |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by Nobody: 9:03am On Nov 04, 2021 |
A001: Existence/Reality can be considered as the quality of being what exists or being what is real It is the same as the truth It exists in different forms to which there's no limit But anything that is real possesses limits as it is just one of the infinite things that exist The limits show that it is a specific object with a specific size or the specific property of a specific object So,existence can also be considered as the property of something to possess limits towards a specific size But existence itself has no limit There's no such thing as the totality of existence since existence has no beginning/end The truth is being displayed in different ways Existence is being displayed in different ways Reality is being displayed in different ways There's no limit to what is happening or the property of something to possess limits or what is being displayed What is happening is what is being displayed or the property of something (a specific object or the property of a specific object ) to possess limits towards a specific size |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 9:23am On Nov 04, 2021 |
Crystyano:Whether there's something called the totality of existence or not, I'm less concerned. This thread isn't meant to discuss such a philosophical argument. Please, don't derail the thread. |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 9:36am On Nov 04, 2021 |
Could our Universe be Someone’s Chemistry Project? It is a pivotal time for astrophysicists, cosmologists, and philosophers alike. In the coming years, next-generation space and ground-based telescopes will come online that will use cutting-edge technology and machine learning to probe the deepest depths of the cosmos. What they find there, with any luck, will allow scientists to address some of the most enduring questions about the origins of life and the Universe itself. Alas, one question that we may never be able to answer is the most pressing of all: if the Universe was conceived in a Big Bang, what was here before that? According to a new op-ed by Prof. Abraham Loeb (which recently appeared in Scientific American), the answer may be stranger than even the most “exotic” explanations. As he argued, the cosmos as we know it may be a “baby Universe” that was created by an advanced technological civilization in a lab! As the former chair (2011-2020) of the astronomy department at Harvard University, the founding director of Harvard’s Black Hole Initiative (BHI), the director of the Institute for Theory and Computation (ITC) at the Harvard-Smithsonian Center for Astrophysics (CfA), and one of the chief researchers with the Galileo Project, Loeb is no stranger to “exotic” theories about advanced intelligence and cosmic origins. https://www.youtube.com/watch?v=--jeD7TG2Us His credentials also include chairing the National Academies’ Board on Physics and Astronomy, the advisory board for Breakthrough Starshot, and being a member of the President’s Council of Advisors on Science and Technology. He is also the author of the bestselling book “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth,” which addressed the possibility that the interstellar object ‘Oumuamua was an artificial probe. This time around, it’s the foundations of the Universe itself (and whether or not aliens may have been involved) that have attracted Loeb’s interest. For starters, there have been many conjectures as to what might have existed before the Big Bang. Some of the more well-known examples include that the Universe emerged from a vacuum fluctuation or that it is a cyclic process with repeated periods of contraction and expansion – Big Bang, Big Crunch, repeat. There is even the notion that the Universe was born from matter collapsing inside a black hole in another Universe, which then rebounded to form the other side of the Einstein–Rosen bridge (a “wormhole”) where our Universe was conceived. A similar version of this argument states that the Big Bang could have been a supermassive “white hole” that formed from a supermassive black hole (SMBH) in our parent universe. Yet another theory is that our Universe is a consequence of the string theory interpretation of the multiverse, where infinite Universes coexist, and every possibility plays out an infinite number of times. According to Loeb, this could take the form of our Universe being created in a laboratory by an advanced civilization. “Since our universe has a flat geometry with a zero net energy, an advanced civilization could have developed a technology that created a baby universe out of nothing through quantum tunneling.” https://www.youtube.com/watch?v=rhFK5_Nx9xY In the context of quantum physics, tunneling refers to a phenomenon where a wave function can propagate through a potential barrier. This plays an essential role in physical phenomena, ranging from nuclear fusion and tunneling electron microscopes to quantum computing. Unfortunately, the Standard Model of particle physics models cannot resolve how quantum mechanics and gravity interact, hence why a Theory of Everything (ToE) is still lacking. However, a sufficiently advanced species may have already developed a ToE and the technology for creating baby Universes. In essence, this theory offers a possible origin story that appeals to the religious notion of a creator and the secular notion of quantum gravity alike. It suggests that a Universe like our own – which hosts at least one civilization (i.e., us) – is like a biological system that reproduces over generations. As Loeb explained to Universe Today via email: "It explains the Big Bang as an infinite series of baby universes born inside each other, just like chicks hatching out of eggs and laying new eggs later in their life. " If something predated this series of generations – it would have been something else, just as in the ‘chicken and egg dilemma.'” This is reminiscent of the Kardashev Scale, which characterizes civilizations by Type (I, II, and III) based on the amount of energy they can harness. Whereas Type Is are able to harness the energy of their entire planet, Type II civilizations can harness the energy of their whole star systems, and Type IIIs can harness the energy of their entire galaxy. In this case, says Loeb, the metric is a civilization’s ability to reproduce the astrophysical conditions that led to their existence. For some, this whole Baby Universe theory might sound similar to the Zoo Hypothesis – a proposed resolution to the Fermi Paradox. But as Loeb explained, there’s a fundamental difference between the two: “The Zoo is a place where you watch the animals, but a baby universe cannot be observed from the outside according to General Relativity, Einstein’s theory of gravity. The interior of the baby universe disappears from view of the creator and snaps out of the creator’s spacetime. The situation is analogous to the formation of a black hole, where all the matter that falls into it cannot be observed once it enters the black hole horizon. “As a result the creator of the baby universe will never know which type of civilization formed in it and will also not be able to intervene. Creating a baby universe might not consume energy because the negative gravitational energy cancels out the positive energy of matter and radiation in our universe, which is characterized by a flat geometry. “The fate of our Universe is completely independent of the baby universe, just as the history of a person that enters the event horizon of a black hole has no influence on us. Based on everything we know, our own universe will expand forever.” Another appealing feature of this theory is the way it’s free of anthropic reasoning, which essentially states that the Universe was selected for us to exist in. Formally known as the Anthropic Principle, this stands in opposition to the Copernican Principle (or Cosmological Principle) that asserts that there is nothing special or unique about humanity or the space we occupy in the Universe. However, the mere fact that slight variations in the laws of physics would rule out life would seem to suggest that we are fortunate. In recent years, it has been suggested that multiverse theory is a possible resolution for the Anthropic Principle. The Baby Universe theory is consistent with this idea, as it theorizes that the Universe gives rise to advanced civilizations that are drivers of a cosmic Darwinian selection process. At present, humanity is not advanced enough to replicate the cosmic conditions that led to our existence. Whereas a civilization that could recreate these cosmic conditions (i.e., produce a “baby Universe” in a laboratory) would fall into class A on this proposed cosmic scale, a class B civilization could adjust the conditions in its immediate environment to be independent of its host star. Given our present situation, humanity is currently a class C or D since we cannot recreate the habitable conditions on our planet (when our Sun dies) and are carelessly destroying planet Earth through climate change. But eventually, humanity may reach the point where we become a class A civilization and can partake in the hypothesized process of cosmic reproduction. Who knows? Maybe we will even be able to create a baby Universe that is an improvement over our own. Loeb contends that such hopes may be a tad optimistic but that the prospect for cosmic procreation presents some very inspiring possibilities: "We are getting close to producing synthetic life in our laboratories. Once we will understand how to unify quantum mechanics and gravity, we might know how to make a baby universe in the laboratory. The ethics of making another universe would be similar to making another human being... “But ultimately, it would be flattering to our species if the abilities that past generations assigned to God, namely creating a universe and creating life in it, will be at our disposal as an advanced scientific civilization. If another civilization that predated us by a billion years had reached that goal already and we will encounter it one day, then that civilization will be a good approximation to what our past religions regarded as God.” Source: https://www.universetoday.com/153107/could-our-universe-be-someones-chemistry-project/amp/ Further reading: https://www.scientificamerican.com./article/was-our-universe-created-in-a-laboratory/ |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by Workch: 9:39am On Nov 04, 2021 |
A001:What we know is that, there’s nothing like “before Big Bang”. It doesn’t make any sense in physics to say “before Big Bang”, unless in the light of big bounce which we are yet to get any evidence for. |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 9:45am On Nov 04, 2021 |
Workch:Yea, you're right. But the author used the phrase to refer to the origin of the Big Bang. How else can he make such a reference without the phrase? |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by Workch: 9:49am On Nov 04, 2021 |
A001:Seriously I don’t know, that’s why it’s a mystery |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 9:51am On Nov 04, 2021 |
Workch:I think the use of the phrase is not that bad. It's strictly a misnomer. |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by Nobody: 4:02pm On Nov 04, 2021 |
Workch: The issue is the definition of the universe But there's no way anything specific can exist alongside or before or after nothing or no other thing that's specific In fact, Since the universe is a combination of several things...not 'all that exists' which is impossible... Then ,it means it was once something else... and it will still become another thing... The Big Bang is not the beginning of what is real What is real has no beginning /end What is real has no limit |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by IMAliyu(m): 8:18pm On Nov 04, 2021 |
Good stuff, following |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 8:47pm On Nov 04, 2021 |
The complete Greek alphabets (upper case and lower case):
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Re: All About Science: Key Facts, Researches, And Discoveries In Physics by Workch: 9:47pm On Nov 04, 2021 |
Lawrence Krauss always say that if you remove all the particles in the universe, the remainder will still weigh something, meaning that nothing still weighs something. He uses it to justify the argument that the universe can come from nothing since nothing still weigh something. |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 9:51pm On Nov 04, 2021 |
Workch:"Nothing" doesn't exist in reality. What we regard or see as nothing is due our limited perception and knowledge. Before the invention of microscopes, humans didn't know of the existence of microorganisms. Then, microorganisms were seen as nothing. Today, we now know they're a key part of our ecosystem. Over time, what we see as nothing will continue to change as more and more advances are made in science and technology. No true vacuum exists in any part of the universe. Something, however minute, must always exist in any specific space.
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Re: All About Science: Key Facts, Researches, And Discoveries In Physics by Nobody: 6:52am On Nov 05, 2021 |
A001: There's no limit to what exists |
Re: All About Science: Key Facts, Researches, And Discoveries In Physics by A001: 12:00pm On Nov 05, 2021 |
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