It's not the maths - it's the physics. The quantum of action represented by Planck's constant gets us "to those values"; going further (or smaller/shorter/more energetic) is not just a question of maths (though it will probably require a different mathematical approach from current ones).
@Brandon Piperjack I'm not sure what you mean - energy measured at a given length? It is true that (for example) the Bekenstein bound is expressed in terms of (amongst other things) Planck's constant and it is related to the entropic content of black holes, and it is true that by combining (in various ways) Planck units you can get to the same limit conditions that would give rise to a Schwarzschild black hole. However, the point I was trying to make is that it's not the mathematical structure that breaks down (unlike for example in calculating "curvature of space-time in a black hole singularity" under GR); it's the actual physical interpretation of the numbers that no longer makes sense: QM formulated in terms of Planck's constant describes nonsense "beyond the Planck units" because what it describes contradicts the (physical) assumptions on which the theory itself is based.
@Brandon Piperjack Nothing to forgive! This may be interesting to read: en.wikipedia.org/wiki/Planck_particle (and the linked article on the "Black Hole Electron"). And this: physics.stackexchange.com/questions/273888/can-a-photon-have-a-wavelength-less-than-the-planck-length/273902
@@dlevi67 Does it make sense to say that it is the shortest possible length, then, if we don't have a theory that accounts for anything shorter? I'm not trying to be pedantic. It's just a philosophical question that arose while I was wondering how it is that I have heard physicists say this.
@@bsadewitz No, you are not being pedantic at all - the 'problem' is a very interesting one, actually: the theory breaks down at the Planck length - as such, it's the shortest meaningful length (or better, distance) that the theory (QM + SR) can describe for particles with mass/energy. We don't have a better theory, but neither do we have a reason to think that space(-time) is quantised at the Planck length (i.e. there is a physical meaning to it). This is partly because some of the other Planck units (e.g. mass) do not seem to represent a meaningful 'limit', and partly because there is some evidence that space is _not_ quantised. You may also find the discussion here interesting: physics.stackexchange.com/questions/185939/is-the-planck-length-the-smallest-length-that-exists-in-the-universe-or-is-it-th
My compliments to you for linking to papers that go into subject matter more in depth! This is needed for those that wish to understand concepts bwyond the cursory .Please continue in future videos.
I've followed the channel for years and this is my favourite Fermilab video. Until now I thought the Higgs Boson going to Church was unbeatable. Thank you Dr. Lincoln!
If Einstein's GR only works in the macro world, how do we know microscopic black holes exist? One of the alleged difficulties of producing a so-called quantum gravity theory is due to the Heisenberg's uncertainty principle. To probe ever tinier distances, we need ever greater energies. The problem is that if you concentrate too much mass in a tiny space, the gravity of such a space becomes so huge that black holes form, making the measurement impossible. This is my question. How do we know that a huge energy allocated to a tiny subatomic region of space would create a black hole, since there is no quantum gravity theory to go by? How do scientists know, what are they basing this idea on, to say that a huge subatomic concentration of energy would lead to a microscopic black hole?
@@ThomasJrMay I can help you to answer your questions, though I'm not a scientist. - So far microscopic black hole is only a theoretical object, scientist only observed the existence of stellar-mass black hole & supermassive black hole - Your questions isn't new to scientist community, a scientist named Bronstein already asking this all the way back in 1930's and thinking how can spacetime be quantized (Which his idea eventually morphed into theory of loop quantum gravity, though not good enough to properly describe our reality) Due to incompatibility description of our reality between quantum mechanics and general relativity, to this day scientists struggle to "marry them" into single theory.
My goodness me - was this one of the best videos yet or what? Thank you so much Don - this scratched so many itches and answered so many questions that were lingering in my mind it is not funny. Thank you for making my week!!!!
Wow good no-fluff explanations without any sensationalism yet the man makes it interesting, entertaining and easy to digest. Never knew the real story behind the Planck units until now.
I wonder what civilization came out with zorblats units and how precise they have to be to measure 1/12 of Planck time. Or it may be the exact opposite, they are so underdeveloped that they use a 12 scale factor as some imperial units, and so they must not even know what they are doing!
@@karellen00 Perhaps they count in base 12, which to some extent would be simpler than base 10, if we were to start from scratch? Or perhaps they name powers of their whatever base (let's say 10) in multiples of 5, and have 10 of them, so rather than having milli/micro/nano etc. they have 10^-5 = "kan", 10^-10 = "lub", ... ,10^-45 = "zor", and a "blat" is 4.5 seconds?
Thank you for this video, after years of me trying to understand Quantum physics and either reading or seeing people talk in absolutes which prickled my mind into more questions than I started out with I can now see that those absolutes were not absolute at all but merely interpretations or extrapolations of what was known. Put more clearly I would read, "this is true therefore this must exist because (complicated mathematics I cannot fully understand)" which did not make sense to me. Persistence has paid off, thanks to people like you, Arvin Ash, PBS Space Time and others I am beginning to see a clearer picture.
Oh, yes, I actually understood the 95% of this (difficult) video and I 'm not a native English speaker. So, as always, I reload it, I prepare a cup of (cold) tea and I watch it...again! Thanks for your job and greetings from Athens, Greece.
This is further to the question and answer regarding fusion and iron. Turning to fission, for instance in current nuclear power reactors, would it be correct to think the energy we derive is actually stored as potential electrostatic energy inside the nucleus? And that the role of the strong nuclear force in fission is really as a kind of "latch" that keeps that electrostatic energy bound up until it's eventuallly released, either spontaneously or through neutron bombardment? Furthermore, for fusion of lighter elements, is it correct to think that the energy we get out is fundamentally from the strong nuclear force, as two light nuclei moving around already have quite a lot of potential energy in the strong nuclear field between them -- or is the strong nuclear force so different that we can't even talk about strong nuclear potential?
That seems largely accurate as a heuristic at least baring a few additional complexities for example as atoms get larger the odds that a number of nucleons, typically Helium 4 for some reason perhaps as it is both a local minimum and acts as a boson which means the Pauli exclusion principal need not apply?, will be able to quantum tunnel out of a nucleus. Note the distinction typically as other nuclear atomic configurations can tunnel out of a nucleus it is just orders of magnitude less likely to happen. Probabilistically this effect ignores energy barriers so you need to think of the latch as somewhat "leaky" due to the whole quantum tunneling effect But yes you can think of the energy difference between the reactants and the products as getting released or absorbed for the reaction to take place and those energy sources are generally based on whether the strong nuclear force or electromagnetic force is dominant.
And further I'm adding with this; stars tends to fusion elements that lighter than iron, up to iron; and there is no more energy left to generate with fusion so we require more energy to create heavier elements. But heavier radioactive elements eventually decays into lead and stops there. Shouldn't it decay more keep giving energy untill it hits to iron again? I thought subatomic particles are lazy and they all tend to stay on lower possible hikikomori energy just like me.
@@Haplo-san I think I can answer that, although not at the deepest level. There are many nuclei that are stable even though they don't have the minimum energy like that of iron. This really goes for most of the stuff you see around you, stable oxygen (lighter than iron), stable gold (heavier than iron). They all have energy, but we don't observe that this energy likes to come out on its own. I hope you are familiar with the nuclide chart, with numbers of protons on one axis and numbers of neutrons on the other axis. There is a squiggly line going roughly diagonally that represents stable combinations of protons and neutrons. Typically there's only one or a few stable isotopes for each chemical element (proton count). You can imagine the nuclide chart also in 3D, where each cell stands as a column, protruding out from the chart with a height indicating how much energy is bound up in the nucleus represented by that cell. Then you'll see a kind of "valley", with the line of stability going down the middle. The sides of this valley can be quite steep, but the valley itself also goes gently uphill as you move towards the heavier nuclei. It also goes uphill towards the lighter elements, where it becomes very steep. In a real valley, a boulder can tumble down towards the lowest point, but often they'll get stuck in some impediment along the way, a local minimum. Equivalently, in the nuclide chart, an unstable heavy nucleus can undergo the various decay modes, moving it to a lower energy state, but the decay chain will typically get stuck in a local minimum. We can make a nucleus unstable by bombarding the material with neutrons and hoping that you get a "direct hit". In some situations, like with Thorium, that can nudge the nucleus into another cell in the chart where the energy bound up in the nucleus becomes more easily accessible, hence the interest in Thorium for energy. (Here I'm ignoring that Thorium is very slightly radioactive, for most practical purposes it's stable.) To spell it out, we are adding a small amount of energy to lift the nucleus out of the local minimum, so it can follow another decay path that may move it closer to the global minimum around iron. In the analogy, this is equivalent to lifting a boulder out of a small trench in order to let it continue tumbling down a valley. Disclaimer: I am not a physicist, and may be wrong.
@@eckligt That was informative, thank you. I imagined something like China's rice terraces. If an atom sitting at higher terrace, you may need a neutrons kick of energy to throw it lower terrace but when it reaches ground level, you will require i-don't-know-how-the-f-loads of energy to dig it more into lighter elements. I also imagined splitting a toothpick into two pieces is easier but keep splitting it more into two pieces becomes a pain very quickly. I was seen this chart before but I wasn't familiar with it, so I will dig more into nuclide chart, it looks interresting. Thanks again.
@@Haplo-san I recommend this video from a French research institute that explains this better than anything else I have come across: th-cam.com/video/UTOp_2ZVZmM/w-d-xo.html Note that you may struggle with their highly accented English.
An interesting bit (Ignoring the ways the current models could break down): - A Planck mass Schwarzschild black hole would be a Planck length across. - A Planck energy photon would have a wavelength of a Planck length. - A Planck energy is equivalent to a Planck mass (via E=mc²). Naively, a photon of that wavelength should, by it self, be a kugelblitz: a black hole formed only from radiation. (Though I suspect that breaks down when you start asking about what reference frame you are measuring from, but it's still fun.)
THank you for clarifying the meaning and essence of Planck's Constant for me, DR. Lincoln. Yes, I until now, had always thought it was the shortest length, or at least the shortest measurable length. Your explanation makes more sense and is more fascinating to me.
Regarding iron and fusion: theoretically we could add lots more neutrons to let nuclei hold together despite having lots of protons, but there seems to be a rule that you can't have more than about 1.5 times as many neutrons as protons before beta decay starts occuring. How is it that protons stabilise neutrons over a wide variety of nucleus sizes but neutrons aren't able to stabilise each other (you don't get stable n4 or anything)?
Neither protons nor neutrons truly "stabilize" each other; instead, atomic nuclei will fill out their protons and neutrons so that, roughly, the highest energy proton and highest energy neutron will have the same energy in the nucleus. This is because the energy levels in general become more spread out as you add more nucleons, so if you had a very energetic proton or neutron relative to the other "stack" of nucleons, it would be more energetically favorable for that very energetic proton/neutron to beta decay into the shorter stack. You should think of them as two different stacks of energy levels because they are not identical particles so the Pauli exclusion principle doesn't apply between them. The reason that nuclei tend to fill with a ratio of about 1.5 neutrons per protons is because the proton energy levels are more spaced out due to electrostatic repulsion (since protons are charged). So, roughly speaking, in a given amount of energy, you can fit 3 neutrons per every 2 protons.
The nuclear force is attractive between protons and neutrons, but is slightly repulsive between likes. And protons do not stabilize nuclei. For any given element there are between zero and a few stable isotopes. (Zero for Z > 82, i.e., those elements beyond lead, no isotopes are stable.) For those isotopes with fewer neutrons than the stable ones, the protons tend to beta decay. For those isotopes with more neutrons than the stable ones, the neutrons tend to beta decay. Both processes bring the given nucleus closer to a stable isotope. Makes sense.
@@betaneptune In the first case it is called beta plus (or positron emission) in the second its beta minus. If the neuton "surplus" is even higher the isotope might undergo double beta decay, neutron emission or in extreme cases double neutron emission (this last two happens on the nutron drip line). In case of proton "surplus" it can undergo electron capture or proton emission in case if it is on the proton drip line. These aren't even all the possibilities depending on what type of isotopes we talk about there could be many hierarchicly ranked way to decay (depending on the probabilities and the forces at play). As an interesting note, Ni-62 has a higher binding energy/nucleon than Fe-56 which was mentioned in the video.
1) Dineutronium has apparently been detected, briefly, and there was apparently an unreplicated report of tetraneutronium (n4). en.wikipedia.org/wiki/Neutronium 2) I came across this interesting uncited nugget on Wikipedia that seems to answer your question, if it's correct: """At small separations between nucleons (less than ~ 0.7 fm between their centers, depending upon spin alignment) the force becomes repulsive, which keeps the nucleons at a certain average separation. For identical nucleons (such as two neutrons or two protons) this repulsion arises from the Pauli exclusion force. A Pauli repulsion also occurs between quarks of the same flavour from different nucleons (a proton and a neutron). [...] The nuclear force has a spin-dependent component. The force is stronger for particles with their spins aligned than for those with their spins anti-aligned. If two particles are the same, such as two neutrons or two protons, the force is not enough to bind the particles, since the spin vectors of two particles of the same type must point in opposite directions when the particles are near each other and are (save for spin) in the same quantum state. This requirement for fermions stems from the Pauli exclusion principle. For fermion particles of different types, such as a proton and neutron, particles may be close to each other and have aligned spins without violating the Pauli exclusion principle, and the nuclear force may bind them (in this case, into a deuteron), since the nuclear force is much stronger for spin-aligned particles. But if the particles' spins are anti-aligned the nuclear force is too weak to bind them, even if they are of different types.""" 3) The maximum number of neutrons per proton isn't really 1.5. Rather, the number of neutrons needed per proton to avoid β-decay, also known as "beta-stability", goes up steadily as the number of protons goes up. If you plot known nuclides on a graph of half-lives or any other measure of stability, they fall in a very clear curve called the "valley of stability", which starts out following the line of Z=N (where Z=# of protons and N=# of neutrons), but then gradually curves in the direction of having more and more neutrons per proton. en.wikipedia.org/wiki/Valley_of_stability (For example Carbon usually has 6 protons and 6 neutrons, and 1.5*6=9 neutrons would give Carbon-15, whose half-life is 2.45 seconds. Uranium, on the hand, usually has 92 protons and 146 neutrons, a ratio of ~1.59, and a ratio of 1.5 would give Uranium-230, whose half-life is 20.8 days. Proton-count affects the ideal ratio a lot, and nuclides can be very picky about this ratio.) This is actually the major hurdle in making superheavy elements. There are actually predicted "islands of stability" in super-heavy nuclides, where elements may have most-stable isotopes that are more stable then the elements before them, analogous to how Thorium and Uranium are more stable than the elements from Polonium to Actinium. In fact, the next predicted one is of elements that have already been synthesized, specifically centered around Flerovium-298 or somewhere thereabouts. That "island" lies approximately along the natural continuation of the known "valley" of beta-stability, and is also predicted to be more stable against α-decay and spontaneous fission, which are the main cause of the holes that appear late in the valley. The problem is that current methods of synthesizing superheavy elements can only make neutron-poor elements, by the standards of elements with such high proton counts (a.k.a. atomic numbers), because they can only make them by smashing together smaller elements, which all have much lower N/Z ratios (because if they didn't they would β-decay). For example, the highest-N/Z ratio, and also longest-lived, isotope of Flerovium ever made is Flerovium-290, or possibly Flerovium-289, rather lower in N/Z than the Flerovium-298 that I mentioned. 4) The previously described effect can be understood in the following way: The nuclear force (a.k.a. "residual strong force") decays at a rate that is much faster than the square of the distance (because it's "mediated" by virtual particles that have mass and decay, so distance does more than just cause the force to spread out over more area). Thus, as nuclei get bigger, the repulsive force grows faster than the attractive force and more neutrons are needed per proton. To use something like Don Lincoln's analogy, if you increased the number of nucleons in the nucleus without changing the N/Z ratio, then the number of protons, and therefore the positive charge, would go up proportionally to volume, while the distance between them would only go up at the cube-root of this rate, meaning that the repulsive force per unit charge would only go down with the r^2 rather than the r^3 rate at which charge is going up. (This is the square-cube-law.) On the other-hand, the nuclear force acts "more like a contact force" and would not go up in this way. Thus, larger nuclei would be less stable. This can be averted by keeping the protons further apart from each other in larger nuclei, e.g., if the proton-density goes down proportionally to radius, than the repulsion-per-unit charge will go down with the cube of the radius as the charge goes up now only with the square of radius, shifting the balance the other way (thus the actual balance would be less extreme than this). Since the nuclear force is more like a contact force, increasing the distance between protons means you have to add more neutrons to fill in that space between the nuclei. (I don't think that's exactly how it works, spatially, but I think it's a good metaphor.)
Good video as usual, thanks so much. But... Could the Planck length be actually *smaller* than the real minimum physical size, if this should happen to be quantized? Thank you
I have always, since my early childhood, asked questions about the world around me, always wondered about everything, and almost always thinking about everything I could. I brainstorm about things much more than most people, yet these scientists from decades and even centuries ago simply shock and amaze me with their insight, intelligence and the ability to come up with these superb solutions. Though I can understand almost everything, I currently can't fully comprehend how these scientists were able to develop these theories and formulas. It forces me to humbly admit that there are levels of intelligence beyond my grasp, gifted to very few people in the world.
So question about time dilation. If going close to light speed dilates your time more and more, does going slower shrink your time til it’s infinitely small?
6:02 "OK. Hopefully I taught you something you didn't know and given you something to ponder." That you did, Dr. Don. I knew about the Planck length, but not the connection to its being the smallest size based on *current understanding of physics.* Thanks!
Him: It's been said that the Planck length is the smallest length, but that's not the entire tale, as I will tell you in this week's episode of sub, sub, Subatomic Stories. Me: Good one, Don!
Let's see, something like if the space is expanding faster than a particle can move through it, that particle will actually lose energy to the expansion. Photons red shift, electrons slow down.
If Einstein's GR only works in the macro world, how do we know microscopic black holes exist? One of the alleged difficulties of producing a so-called quantum gravity theory is due to the Heisenberg's uncertainty principle. To probe ever tinier distances, we need ever greater energies. The problem is that if you concentrate too much mass in a tiny space, the gravity of such a space becomes so huge that black holes form, making the measurement impossible. This is my question. How do we know that a huge energy allocated to a tiny subatomic region of space would create a black hole, since there is no quantum gravity theory to go by? How do scientists know, what are they basing this idea on, to say that a huge subatomic concentration of energy would lead to a microscopic black hole?
Dear friend in Physics of the Universe! I am enlightened by your illustrative videos and FermiLab's (USA's) Scientific contributions to the Humanity 💐❣️🙏 Absolutely thank you so much and the whole staff of the FermiLab, USA. You are all great support to all the Human beings in all countries/ nations of the world 🌎🤗🌍🌄
@@divyanshvishwkarma9548 And my english is to weak to write this good but I think that entanglement is above time and space. And even event horizon is no barrier for this.
Conditions under the event horizons changes a lot, for instance Space and Time swapping their role (or properties to say) And any event that occurs under event horizon doesn't have any effect on an outside observer, And I am not a physicist now but can say that the monster will either break the entangled, or if it didn't, only a clever experimental physicist can find it😁😁
Cannot believe you actually got out “astrophysicist are known to be dull and not funny “ without Neil deGrass Tyson cutting you off and telling his side instead!!! Lol
"... I know you didn't ask me, but..." ;) I really appreciate what Neil deGrasse Tyson does and did for the public awareness of science, though I do think he took it a bit too far. His podcasts with Chuck Nice are some of the unfunniest things I've ever seen. I'd love to see more in-depth videos from him, which are lacking lately. When he's able to put his ego aside, he's a great communicator.
@@ThelemicMagick true, what you said I agree. I can't stand watching Neil, nothing I saw I liked, but its what appeals to the masses is most important. Its like donald trump for conservatives/racists/2nd amendment gun toters. Same goes with left leaning liberal idiots/sjw dimwits/snowflakes. Of course its not this serious, etx, but the idea is the same, the underlying truth about society, and the mass population is the same: fickle like anything, band wagon jumpers. I wish we had good leaders, moral leaders, and role models. I'd vote Dr. Lincoln as one.
He isnt an astrophysicist. When was the last time he did any real science? decades ago. For the most part his contributions are posting self-important tweets.
If Einstein's GR only works in the macro world, how do we know microscopic black holes exist? One of the alleged difficulties of producing a so-called quantum gravity theory is due to the Heisenberg's uncertainty principle. To probe ever tinier distances, we need ever greater energies. The problem is that if you concentrate too much mass in a tiny space, the gravity of such a space becomes so huge that black holes form, making the measurement impossible. This is my question. How do we know that a huge energy allocated to a tiny subatomic region of space would create a black hole, since there is no quantum gravity theory to go by? How do scientists know, what are they basing this idea on, to say that a huge subatomic concentration of energy would lead to a microscopic black hole?
Thanks. FINALLY! Someone that doesn't spew nonsense that the Planck length is the end all to be all. Important? Yes. The answer to what is below that length? To be determined using math not invented yet. Cheers.
Hi, great video. Has anyone suggested the dark photons as candidates for the hidden variables proposed by Eisten to overcome quantum mechanic uncertainty?
scientists: "Energy is not conserved" Me: I been lied to my whole life... Seriously, down with normal "education" and the established media, we all need to get our info from the SAUCE
joaquin vega Conservation of energy is still the best rule to follow for nearly every phenomena you can see in your everyday life. Especially if an investor aproaches you with his idea about infinite free energy...
Sure. Everyone should be taught general relativity in first grade. The fact that the kids can't even add yet shouldn't stop them from solving the Einstein field equations.
your shows are the best, love how you explain things tha twork. you should do a live show some time so people can ask you questions directly. thank you for the show.
Finally, someone explained what's actually going on with the plank length. The way that the plank length came from a hodge-podge of the Standard Model and gravity and yet was also said to be the smallest distance with 100% certainty always didn't make sense to me.
Also, regarding your comments on energy conservation, if you consider a photon is just an spacial aperture to a big bang temperature and expanding space changes the wavelength of that expression, it is easy to understand that the core energy of the photon has not changed, only the spacial apertures' behaviour of collapse has changed. B-)
It's critical what you said at 5:52 about the Planck length not necessarily being the shortest size, it's just where current physics breaks down. I haven't heard a physicist saying that before but it makes perfect sense to me. Seems the problem is about the basic definition of reality, reality is being defined as that which can be measured which is fine for all practical purposes but should reality be limited to our ability to measure? Could there be particles too small to measure or have any impact on our physical universe?
Dr Don, the videos are just getting better and better, thank you for the great information and humor :) And, Americans, you should vote this guy your president !
I noticed several years back that a photon with a wavelength of a planck length would have just exactly enough gravity to trap itself in a resonant orbit at a diameter of the planck length. It is the only wavelength of any photon where the mass equivalent and swartzchild radius converge as smaller wavelength photons would have a larger swartzchild radius and longer ones would have a shorter swartzchild radius. It seems that any photon with a wavelength smaller than the planck length would have a mass great enough that it would be some kind of singularity.
1. The mass of photons is _zero_ regardless of their wavelength. You must be talking about “relativistic mass” which is an outdated, deprecated concept. See also: ”Fermilab: Is relativistic mass real?” th-cam.com/video/LTJauaefTZM/w-d-xo.html 2. Objects do not “have gravity”; gravity is an *interaction* between several objects/particles. 3. The term is “ _Schwarzschild_ radius”: en.wikipedia.org/wiki/Schwarzschild_radius 4. It is possible in general relativity to have a black hole from energy that does not originally come from mass. When it comes from photons, it is called a “kugelblitz”, a special case of a geon: en.wikipedia.org/wiki/Kugelblitz_(astrophysics) 5. I wonder how you conclude from a wavelength to a particular orbit, but I will think about the possibility.
@@ThomasLahn I think what I should have said is that there is a certain planck scale wavelength photon that would trap itself in resonance at its own Swarzschild radius where the diameter is an integer of the wavelength/2. I think it is 2pi planck length. For all other photons with shorter or longer wavelengths, the wavelength and Swartzchild radii diverge dramatically.
@@mertonhirsch4734 The _SCHWARZSCHILD_ radius is given by rₛ = 2 G M/c² = 2 G E/c⁴, where I have applied M = E/c² to obtain the mass equivalent to a given energy (this semiclassical approximation works well for gravitational redshift by white dwarfs, so maybe here, too.) A photon whose wavelength is the Planck length lₚ ≈ 1.6163 × 10⁻³⁵ m has the energy E = ℎ f = ℎ c/λ = ℎ c/lₚ ≈ 12.29 GJ. [This corresponds to hard gamma rays.] Therefore, the Schwarzschild radius of such a photon would be rₛ = 2 G ℎ c/(c⁴ lₚ) = 2 G ℎ/(c³ lₚ) ≈ 2.031 × 10⁻³⁴ m ≈ 12.57 lₚ. So you can see that the Schwarzschild radius would be considerably greater than the Planck length. You appear to think that the wavelength of a photon would have to do with the space that it occupies. But (AFAIK) that is not so. Photons are elementary particles, assumed as point-like, and we cannot tell exactly where they are (Heisenberg uncertainty relation: σₓ σₚ ≥ ℏ/2). They are not in any orbit (the Bohr model already fails to describe electrons; it surely fails for photons); we can only calculate probabilities of them being detected for regions where we want to detect them. Only if, for some reason, the photon would be constrained inside a radius that is much smaller than its own Schwarzschild radius, then it would be a kugelblitz and a microscopic black hole with a fuzzy event horizon (since the position of the photon and its wavelength would be uncertain) would form around that region (assuming that GR would be applicable). But then the photon would still not be orbiting anything: inside that radius, all geodesics point inward, and since it is already at the singularity that it created, it would be stuck, and it is questionable whether it could even exist as there are no photons at relative rest. On the other hand, such a microscopic black hole would evaporate in 1.18814 × 10⁻³⁷ s (if Hawking is correct; calculated with Viktor T. Toth’s Hawking radiation calculator), so it is not clear what would happen (does the photon continously regenerate black holes as it is trapped in that region?). A theory of quantum gravity is required here. Also, you have to consider that for the photon to be constrained to that region, an enormous amount of energy (namely at least the energy of the photon again; see above) would be necessary in addition to the energy that it already has. If I understood Don Lincoln’s video “The Origins of Mass” correctly, that energy would be added to that system, at least doubling the Schwarzschild radius. Finally, try jila.colorado.edu/~ajsh/bh/quiz.html#quiz to clarify some misconceptions about black holes that you appear to have :)
@@ThomasLahn Just wanted to point out that the value you got: ≈ 2.031 × 10⁻³⁴ m is exactly 4pi x the planck length. I believe that I didn't use a planck length. I think that if you start with a 2 x planck length photon you get a 2pi planck length S.C. radius.
@@mertonhirsch4734 No, the Schwarzschild _radius_ of that photon is _approximately_ 4π lₚ, and you argued _2_ π lₚ for the _circumference_ of its orbit (no doubt based on the Bohr atomic model and de Broglie wavelength of electrons) before. Seeing seeming relations in and between numbers, especially when irrational numbers are involved, after the fact, by careless rounding, is numerology, not science. See also: en.wikipedia.org/wiki/Kees_de_Jager#Cyclosophy Bohr (and Sommerfeld) were wrong: Electrons are not orbiting in circles with radiuses corresponding to their (de Broglie) wavelengths (or in ellipses); neither are photons. And light is not orbiting black holes at the Schwarzschild radius, but further out (you should have taken the quiz). Your idea does not add up.
Regarding the question of Nick Fontaine about the super strong cable that lowers a camera below the event horizon: the event horizon is not some kind of dark velvet curtain that covers the singularity from our eyes. It's the surface at which the gravity created by the singularity requires faster-than-light escape velocity. And below the event horizon the gravity is even stronger, so the escape velocity is even higher. As a result, the inside of the black hole must be also black, provided that it's a simple non-rotating black hole. If it does rotate, then it's not so obvious what's inside. For knowing more, I recommend the excellent PBS Spacetime youtube channel.
Dr, Lincoln : My avocation is physics (particle) but not my vocation. I am saying and asking this simply for an elementary explanation of the latest breakthroughs that you may know regarding fusion energy - NASA seems to indicate advances are being made but that is all I could ascertain as to what they have found. Any ideas ?
All quantities can be measured with just two basic units: the second, s, and the electronic charge, e. Both distances and time intervals between events can be measured in units of the second. Energy, momentum, mass, acceleration, temperature and frequency can all be measured in units of the reciprocal of the second, s⁻¹. The speed of light in vacuum, entropy and angular momentum are dimensionless in these units.
Speaking of black hole secrets.. is it possible to send out a message from inside the event horizon via gravitational waves? For instance, if two black holes are orbiting each other closely, they would form a single event horizon but you can maybe modulate frequency/amplitude of the gravitational waves and thus send a message out?
May I suggest to put the thing you read from a bit further away from the camera and a bit closer in line with the camera sight. In that way it becomes less obvious you read lines which shows in the eye movement and makes it more natural by creating the perception you look at the viewer while talking. Improving production quality and such.
We've learned two things from Brian May's work: 1) as long as your thesis doesn't take longer than 37 years to finish, you're not a slacker; 2) astrophysicists quote Kansas lyrics in their theses. (If you want Disney lyrics, you have to look to particle physicists).
I learned something nifty today! So now I get to talk about a fun weird little bizarre fact about the Planck units. When you start looking at the extended list of DERIVED Planck units, you come across one that makes you scratch your head a bit. It certainly made me scratch mine! It's called the Planck resistance, and it comes out to be... 30Ω. Thirty ohms. For someone who used to be quite firmly in the camp of believing the planck units were the absolute physical limits of things (the smallest, the least massive, the hottest, the whateverest), this baffled my electrical engineery brain! There's resistances that can be considerably smaller and bigger than this planck resistance! So what gives!?!? Turns out it's just the number that comes out in the wash when you combine the planck units in the same way that the ohm is defined. It's nothing more special than the resistance that is defined by the fundamental constants of nature, when those constants are taken to equal 1 unit of whatever thing they define. This little subatomic story enlightened me tonight and made me realize what should have been obvious this entire time. :)
Physics Explained has a great video on Planks lengths, apparently nothing can be closer to each other than this lenght otherwise black hole forms, and since even light can't escape black hole we can't retrieve any meaningful information from it; so maybe smaller things exist we just have no means to detect it on such scale
Isn't possible to see the lost of energy of the photon going through expanding space as just being diluted on more "space" ? the energy is still there but on a larger area thus the bigger wavelength ?
I believe energy is always conserved however we humans simply haven't worked out the kinks yet How is energy transferred to space and time to create the curvature of such
As the universe expands it red-shifts light. That reduces the energy of the light. Has anyone calculated if energy was conserved then the intensity of the microwave background would be higher. But that would also mean that one photon of energy leaving would result in more photons at the destination.
@@LaserFur light is an excitation of a field, if the field expand with the universe, isn't it normal for a vibration to expand too ? Thus the energy is locally lower because it spread across a bigger region ??
@@Tutul_ not counting the normal divergence of the light or dust along the path. The expansion of space itself lowers the wavelength. At a detector it measures less energy, but yes that energy would be over a longer period of time. So energy is conserved in this case.
Thank you, I've noticed that this misconception is often floating around. Are there any ideas for how we could measure things at smaller scales? (I have a hypothesis that what we think of as point particles may be solid objects with diameters far shorter than the planck length)
A great program and great effort and a great presenter. Small comment. Energy is conserved not because of Noether theory. It is conserved because momentum is conserved or the world is symmetric, from which energy conservation is derived. E=(1/m) integral(mv.dmv)=.5 m v^2. Regards.
Please address the lack of a theory of quantum measurement. That is, why is there no formula for the collapse of the wave function. Thanks for your series. Excellent.
You are an amazing educator. Thank you so much for bringing all this amazing wondrous content and presenting it in a way that I can understand at least some of it! Lol! I wondered if there might be a chance to cover ‘Wigner’s Friend’ please and any more recent developments on this? Once again, Thank you hugely!
Thanks for answering my question Dr. Lincoln. I appreciate the links to more info and will certainly read them!
Yes, this was a great question and a superb reply. Really enjoyed this and I will check out the links too.
hello
Ugga bugga.
Ugga bugga boo.
It truly warms my heart to see Fermilab’s TH-cam channel doing so well 🥰 it gives me hope for the future
I weep for the future
I am glad that there is so many people that like technical stuff like this!
A wonderful episode of Subatomic Stories. I learned so much new about our world! Thank you very much for this series Don Lincoln!
Thank you, Don. The planck length being the length where our math breaks down answers questions and misconceptions I’ve had for years.
It's not the maths - it's the physics. The quantum of action represented by Planck's constant gets us "to those values"; going further (or smaller/shorter/more energetic) is not just a question of maths (though it will probably require a different mathematical approach from current ones).
@Brandon Piperjack I'm not sure what you mean - energy measured at a given length? It is true that (for example) the Bekenstein bound is expressed in terms of (amongst other things) Planck's constant and it is related to the entropic content of black holes, and it is true that by combining (in various ways) Planck units you can get to the same limit conditions that would give rise to a Schwarzschild black hole.
However, the point I was trying to make is that it's not the mathematical structure that breaks down (unlike for example in calculating "curvature of space-time in a black hole singularity" under GR); it's the actual physical interpretation of the numbers that no longer makes sense: QM formulated in terms of Planck's constant describes nonsense "beyond the Planck units" because what it describes contradicts the (physical) assumptions on which the theory itself is based.
@Brandon Piperjack Nothing to forgive!
This may be interesting to read: en.wikipedia.org/wiki/Planck_particle (and the linked article on the "Black Hole Electron"). And this: physics.stackexchange.com/questions/273888/can-a-photon-have-a-wavelength-less-than-the-planck-length/273902
@@dlevi67 Does it make sense to say that it is the shortest possible length, then, if we don't have a theory that accounts for anything shorter?
I'm not trying to be pedantic. It's just a philosophical question that arose while I was wondering how it is that I have heard physicists say this.
@@bsadewitz No, you are not being pedantic at all - the 'problem' is a very interesting one, actually: the theory breaks down at the Planck length - as such, it's the shortest meaningful length (or better, distance) that the theory (QM + SR) can describe for particles with mass/energy.
We don't have a better theory, but neither do we have a reason to think that space(-time) is quantised at the Planck length (i.e. there is a physical meaning to it). This is partly because some of the other Planck units (e.g. mass) do not seem to represent a meaningful 'limit', and partly because there is some evidence that space is _not_ quantised. You may also find the discussion here interesting: physics.stackexchange.com/questions/185939/is-the-planck-length-the-smallest-length-that-exists-in-the-universe-or-is-it-th
I still haven't decided what I think about the uncertainty principle.
Simple yet elegant. Well done
😆
Don't put too much energy in it or you might not get away
You must be too sure about something else.
Brilliant. Good job there.
My compliments to you for linking to papers that go into subject matter more in depth! This is needed for those that wish to understand concepts bwyond the cursory .Please continue in future videos.
I've followed the channel for years and this is my favourite Fermilab video. Until now I thought the Higgs Boson going to Church was unbeatable.
Thank you Dr. Lincoln!
Where did the Time Crystal one fit in? That was at least funny.
@@drdon5205
Watch only if hav'nt earlier.
th-cam.com/video/nnkvoIHztPw/w-d-xo.html
How about ....
th-cam.com/video/nnkvoIHztPw/w-d-xo.html
If Einstein's GR only works in the macro world, how do we know microscopic black holes exist?
One of the alleged difficulties of producing a so-called quantum gravity theory is due to the Heisenberg's uncertainty principle.
To probe ever tinier distances, we need ever greater energies. The problem is that if you concentrate too much mass in a tiny space, the gravity of such a space becomes so huge that black holes form, making the measurement impossible.
This is my question. How do we know that a huge energy allocated to a tiny subatomic region of space would create a black hole, since there is no quantum gravity theory to go by?
How do scientists know, what are they basing this idea on, to say that a huge subatomic concentration of energy would lead to a microscopic black hole?
@@ThomasJrMay I can help you to answer your questions, though I'm not a scientist.
- So far microscopic black hole is only a theoretical object, scientist only observed the existence of stellar-mass black hole & supermassive black hole
- Your questions isn't new to scientist community, a scientist named Bronstein already asking this all the way back in 1930's and thinking how can spacetime be quantized (Which his idea eventually morphed into theory of loop quantum gravity, though not good enough to properly describe our reality)
Due to incompatibility description of our reality between quantum mechanics and general relativity, to this day scientists struggle to "marry them" into single theory.
Between Subatomic Stories and Sean Carrolls videos I expect my PHD in Physics to arrive by the end of the year! Thank you!
If it helps
Spin of Indivisible Particle : Watch...
th-cam.com/video/nnkvoIHztPw/w-d-xo.html
My goodness me - was this one of the best videos yet or what? Thank you so much Don - this scratched so many itches and answered so many questions that were lingering in my mind it is not funny. Thank you for making my week!!!!
I've said it before and I'll say it again: I absolutely LOVE this video series.
Wow good no-fluff explanations without any sensationalism yet the man makes it interesting, entertaining and easy to digest. Never knew the real story behind the Planck units until now.
Yay, new vid from Dr. Don! 💖🌌
Tip: always know your plank length before you go to the hardware store.
is 6 inches a good planck length?
Measure twice, cut once
@@mellowfellow6816 that's exactly what my parents thought too, but then they changed their minds when my brother was born
I have a ruler that shows light distance... Got it through V Sauce Curiosity box.
th-cam.com/video/_Y8HgmOoLCM/w-d-xo.html
Thank you for explaining the Plank length issue...it took 5 videos but your finally was clear enough to understand.
" Planck time = zorblats " ...I need that tshirt
12 zorblats! Come on man, be precise!
I wonder what civilization came out with zorblats units and how precise they have to be to measure 1/12 of Planck time. Or it may be the exact opposite, they are so underdeveloped that they use a 12 scale factor as some imperial units, and so they must not even know what they are doing!
@@karellen00 Perhaps they count in base 12, which to some extent would be simpler than base 10, if we were to start from scratch?
Or perhaps they name powers of their whatever base (let's say 10) in multiples of 5, and have 10 of them, so rather than having milli/micro/nano etc. they have 10^-5 = "kan", 10^-10 = "lub", ... ,10^-45 = "zor", and a "blat" is 4.5 seconds?
@@Thishandlewasvailable zorTblats!
12. 12 Zzorblats to the plank. Gotta be 12. Maybe even more.
Thank you for this video, after years of me trying to understand Quantum physics and either reading or seeing people talk in absolutes which prickled my mind into more questions than I started out with I can now see that those absolutes were not absolute at all but merely interpretations or extrapolations of what was known. Put more clearly I would read, "this is true therefore this must exist because (complicated mathematics I cannot fully understand)" which did not make sense to me. Persistence has paid off, thanks to people like you, Arvin Ash, PBS Space Time and others I am beginning to see a clearer picture.
I will henceforth quote my age in Zortblats
@Roger Dodger 2.9x10^52 Zortblats per Dog Year.
Oh, yes, I actually understood the 95% of this (difficult) video and I 'm not a native English speaker. So, as always, I reload it, I prepare a cup of (cold) tea and I watch it...again! Thanks for your job and greetings from Athens, Greece.
I understood about 1 zorblat of this talk but still find it interesting .
You are great scholar and teacher sir. I wish and pray God that people like you to be in all education institution to teach science.
Shout out to Dr Lincoln for showing us his childhood photos.
How can you not love these videos. Thank you Mr. Lincoln.
This is further to the question and answer regarding fusion and iron. Turning to fission, for instance in current nuclear power reactors, would it be correct to think the energy we derive is actually stored as potential electrostatic energy inside the nucleus? And that the role of the strong nuclear force in fission is really as a kind of "latch" that keeps that electrostatic energy bound up until it's eventuallly released, either spontaneously or through neutron bombardment?
Furthermore, for fusion of lighter elements, is it correct to think that the energy we get out is fundamentally from the strong nuclear force, as two light nuclei moving around already have quite a lot of potential energy in the strong nuclear field between them -- or is the strong nuclear force so different that we can't even talk about strong nuclear potential?
That seems largely accurate as a heuristic at least baring a few additional complexities for example as atoms get larger the odds that a number of nucleons, typically Helium 4 for some reason perhaps as it is both a local minimum and acts as a boson which means the Pauli exclusion principal need not apply?, will be able to quantum tunnel out of a nucleus. Note the distinction typically as other nuclear atomic configurations can tunnel out of a nucleus it is just orders of magnitude less likely to happen. Probabilistically this effect ignores energy barriers so you need to think of the latch as somewhat "leaky" due to the whole quantum tunneling effect
But yes you can think of the energy difference between the reactants and the products as getting released or absorbed for the reaction to take place and those energy sources are generally based on whether the strong nuclear force or electromagnetic force is dominant.
And further I'm adding with this; stars tends to fusion elements that lighter than iron, up to iron; and there is no more energy left to generate with fusion so we require more energy to create heavier elements. But heavier radioactive elements eventually decays into lead and stops there. Shouldn't it decay more keep giving energy untill it hits to iron again? I thought subatomic particles are lazy and they all tend to stay on lower possible hikikomori energy just like me.
@@Haplo-san I think I can answer that, although not at the deepest level. There are many nuclei that are stable even though they don't have the minimum energy like that of iron. This really goes for most of the stuff you see around you, stable oxygen (lighter than iron), stable gold (heavier than iron). They all have energy, but we don't observe that this energy likes to come out on its own.
I hope you are familiar with the nuclide chart, with numbers of protons on one axis and numbers of neutrons on the other axis. There is a squiggly line going roughly diagonally that represents stable combinations of protons and neutrons. Typically there's only one or a few stable isotopes for each chemical element (proton count). You can imagine the nuclide chart also in 3D, where each cell stands as a column, protruding out from the chart with a height indicating how much energy is bound up in the nucleus represented by that cell. Then you'll see a kind of "valley", with the line of stability going down the middle. The sides of this valley can be quite steep, but the valley itself also goes gently uphill as you move towards the heavier nuclei. It also goes uphill towards the lighter elements, where it becomes very steep. In a real valley, a boulder can tumble down towards the lowest point, but often they'll get stuck in some impediment along the way, a local minimum. Equivalently, in the nuclide chart, an unstable heavy nucleus can undergo the various decay modes, moving it to a lower energy state, but the decay chain will typically get stuck in a local minimum.
We can make a nucleus unstable by bombarding the material with neutrons and hoping that you get a "direct hit". In some situations, like with Thorium, that can nudge the nucleus into another cell in the chart where the energy bound up in the nucleus becomes more easily accessible, hence the interest in Thorium for energy. (Here I'm ignoring that Thorium is very slightly radioactive, for most practical purposes it's stable.) To spell it out, we are adding a small amount of energy to lift the nucleus out of the local minimum, so it can follow another decay path that may move it closer to the global minimum around iron. In the analogy, this is equivalent to lifting a boulder out of a small trench in order to let it continue tumbling down a valley.
Disclaimer: I am not a physicist, and may be wrong.
@@eckligt That was informative, thank you. I imagined something like China's rice terraces. If an atom sitting at higher terrace, you may need a neutrons kick of energy to throw it lower terrace but when it reaches ground level, you will require i-don't-know-how-the-f-loads of energy to dig it more into lighter elements. I also imagined splitting a toothpick into two pieces is easier but keep splitting it more into two pieces becomes a pain very quickly. I was seen this chart before but I wasn't familiar with it, so I will dig more into nuclide chart, it looks interresting. Thanks again.
@@Haplo-san I recommend this video from a French research institute that explains this better than anything else I have come across: th-cam.com/video/UTOp_2ZVZmM/w-d-xo.html
Note that you may struggle with their highly accented English.
You are the best science educator for physics in TH-cam as of now !
An interesting bit (Ignoring the ways the current models could break down):
- A Planck mass Schwarzschild black hole would be a Planck length across.
- A Planck energy photon would have a wavelength of a Planck length.
- A Planck energy is equivalent to a Planck mass (via E=mc²).
Naively, a photon of that wavelength should, by it self, be a kugelblitz: a black hole formed only from radiation. (Though I suspect that breaks down when you start asking about what reference frame you are measuring from, but it's still fun.)
THank you for clarifying the meaning and essence of Planck's Constant for me, DR. Lincoln. Yes, I until now, had always thought it was the shortest length, or at least the shortest measurable length. Your explanation makes more sense and is more fascinating to me.
Regarding iron and fusion: theoretically we could add lots more neutrons to let nuclei hold together despite having lots of protons, but there seems to be a rule that you can't have more than about 1.5 times as many neutrons as protons before beta decay starts occuring. How is it that protons stabilise neutrons over a wide variety of nucleus sizes but neutrons aren't able to stabilise each other (you don't get stable n4 or anything)?
Dineutron (2 neutrons) was observed 8 years ago. So it's not completely unstudied.
Neither protons nor neutrons truly "stabilize" each other; instead, atomic nuclei will fill out their protons and neutrons so that, roughly, the highest energy proton and highest energy neutron will have the same energy in the nucleus. This is because the energy levels in general become more spread out as you add more nucleons, so if you had a very energetic proton or neutron relative to the other "stack" of nucleons, it would be more energetically favorable for that very energetic proton/neutron to beta decay into the shorter stack. You should think of them as two different stacks of energy levels because they are not identical particles so the Pauli exclusion principle doesn't apply between them.
The reason that nuclei tend to fill with a ratio of about 1.5 neutrons per protons is because the proton energy levels are more spaced out due to electrostatic repulsion (since protons are charged). So, roughly speaking, in a given amount of energy, you can fit 3 neutrons per every 2 protons.
The nuclear force is attractive between protons and neutrons, but is slightly repulsive between likes. And protons do not stabilize nuclei. For any given element there are between zero and a few stable isotopes. (Zero for Z > 82, i.e., those elements beyond lead, no isotopes are stable.) For those isotopes with fewer neutrons than the stable ones, the protons tend to beta decay. For those isotopes with more neutrons than the stable ones, the neutrons tend to beta decay. Both processes bring the given nucleus closer to a stable isotope. Makes sense.
@@betaneptune In the first case it is called beta plus (or positron emission) in the second its beta minus. If the neuton "surplus" is even higher the isotope might undergo double beta decay, neutron emission or in extreme cases double neutron emission (this last two happens on the nutron drip line). In case of proton "surplus" it can undergo electron capture or proton emission in case if it is on the proton drip line. These aren't even all the possibilities depending on what type of isotopes we talk about there could be many hierarchicly ranked way to decay (depending on the probabilities and the forces at play). As an interesting note, Ni-62 has a higher binding energy/nucleon than Fe-56 which was mentioned in the video.
1) Dineutronium has apparently been detected, briefly, and there was apparently an unreplicated report of tetraneutronium (n4). en.wikipedia.org/wiki/Neutronium
2) I came across this interesting uncited nugget on Wikipedia that seems to answer your question, if it's correct:
"""At small separations between nucleons (less than ~ 0.7 fm between their centers, depending upon spin alignment) the force becomes repulsive, which keeps the nucleons at a certain average separation. For identical nucleons (such as two neutrons or two protons) this repulsion arises from the Pauli exclusion force. A Pauli repulsion also occurs between quarks of the same flavour from different nucleons (a proton and a neutron).
[...]
The nuclear force has a spin-dependent component. The force is stronger for particles with their spins aligned than for those with their spins anti-aligned. If two particles are the same, such as two neutrons or two protons, the force is not enough to bind the particles, since the spin vectors of two particles of the same type must point in opposite directions when the particles are near each other and are (save for spin) in the same quantum state. This requirement for fermions stems from the Pauli exclusion principle. For fermion particles of different types, such as a proton and neutron, particles may be close to each other and have aligned spins without violating the Pauli exclusion principle, and the nuclear force may bind them (in this case, into a deuteron), since the nuclear force is much stronger for spin-aligned particles. But if the particles' spins are anti-aligned the nuclear force is too weak to bind them, even if they are of different types."""
3) The maximum number of neutrons per proton isn't really 1.5. Rather, the number of neutrons needed per proton to avoid β-decay, also known as "beta-stability", goes up steadily as the number of protons goes up. If you plot known nuclides on a graph of half-lives or any other measure of stability, they fall in a very clear curve called the "valley of stability", which starts out following the line of Z=N (where Z=# of protons and N=# of neutrons), but then gradually curves in the direction of having more and more neutrons per proton. en.wikipedia.org/wiki/Valley_of_stability (For example Carbon usually has 6 protons and 6 neutrons, and 1.5*6=9 neutrons would give Carbon-15, whose half-life is 2.45 seconds. Uranium, on the hand, usually has 92 protons and 146 neutrons, a ratio of ~1.59, and a ratio of 1.5 would give Uranium-230, whose half-life is 20.8 days. Proton-count affects the ideal ratio a lot, and nuclides can be very picky about this ratio.)
This is actually the major hurdle in making superheavy elements. There are actually predicted "islands of stability" in super-heavy nuclides, where elements may have most-stable isotopes that are more stable then the elements before them, analogous to how Thorium and Uranium are more stable than the elements from Polonium to Actinium. In fact, the next predicted one is of elements that have already been synthesized, specifically centered around Flerovium-298 or somewhere thereabouts. That "island" lies approximately along the natural continuation of the known "valley" of beta-stability, and is also predicted to be more stable against α-decay and spontaneous fission, which are the main cause of the holes that appear late in the valley. The problem is that current methods of synthesizing superheavy elements can only make neutron-poor elements, by the standards of elements with such high proton counts (a.k.a. atomic numbers), because they can only make them by smashing together smaller elements, which all have much lower N/Z ratios (because if they didn't they would β-decay). For example, the highest-N/Z ratio, and also longest-lived, isotope of Flerovium ever made is Flerovium-290, or possibly Flerovium-289, rather lower in N/Z than the Flerovium-298 that I mentioned.
4) The previously described effect can be understood in the following way: The nuclear force (a.k.a. "residual strong force") decays at a rate that is much faster than the square of the distance (because it's "mediated" by virtual particles that have mass and decay, so distance does more than just cause the force to spread out over more area). Thus, as nuclei get bigger, the repulsive force grows faster than the attractive force and more neutrons are needed per proton. To use something like Don Lincoln's analogy, if you increased the number of nucleons in the nucleus without changing the N/Z ratio, then the number of protons, and therefore the positive charge, would go up proportionally to volume, while the distance between them would only go up at the cube-root of this rate, meaning that the repulsive force per unit charge would only go down with the r^2 rather than the r^3 rate at which charge is going up. (This is the square-cube-law.) On the other-hand, the nuclear force acts "more like a contact force" and would not go up in this way. Thus, larger nuclei would be less stable. This can be averted by keeping the protons further apart from each other in larger nuclei, e.g., if the proton-density goes down proportionally to radius, than the repulsion-per-unit charge will go down with the cube of the radius as the charge goes up now only with the square of radius, shifting the balance the other way (thus the actual balance would be less extreme than this). Since the nuclear force is more like a contact force, increasing the distance between protons means you have to add more neutrons to fill in that space between the nuclei. (I don't think that's exactly how it works, spatially, but I think it's a good metaphor.)
Wow, so this really deserved a much more compelling title, like, MISCONCEPTIONS ABOUT PHYSICS.
Don: astrophysicists aren't funny.
Matt of Pbs Spacetime: 🙄
Well he might be sorta funny must mostly he's dead serious,his voice,his face,everything.
@@loganwolv3393 Someone is not getting all the jokes :P
Or Dr. Becky
@@loganwolv3393 he has a very dry sense of humor, but I get a good lol once or twice per episode.
@@LeoStaley So easy to miss and hard to appriciate huh? i see.
Hi Don! I hope that you understand that I learn something new and fascinating every episode. Thanks you so much!
Good video as usual, thanks so much. But... Could the Planck length be actually *smaller* than the real minimum physical size, if this should happen to be quantized? Thank you
good question
Min. Physical.....
th-cam.com/video/nnkvoIHztPw/w-d-xo.html
I have never seen someone speak with so much passion about tachyons
Just great. Thank you.
I like that Dr. Lincoln draws a clear distinction between the known and the speculative.
"So, what is it with astrophysicists?" Badum tish!
I have always, since my early childhood, asked questions about the world around me, always wondered about everything, and almost always thinking about everything I could.
I brainstorm about things much more than most people, yet these scientists from decades and even centuries ago simply shock and amaze me with their insight, intelligence and the ability to come up with these superb solutions.
Though I can understand almost everything, I currently can't fully comprehend how these scientists were able to develop these theories and formulas.
It forces me to humbly admit that there are levels of intelligence beyond my grasp, gifted to very few people in the world.
How can we get some of the great t-shirts you wear?
So question about time dilation. If going close to light speed dilates your time more and more, does going slower shrink your time til it’s infinitely small?
Thanks for the history lesson! 👍
6:02 "OK. Hopefully I taught you something you didn't know and given you something to ponder."
That you did, Dr. Don. I knew about the Planck length, but not the connection to its being the smallest size based on *current understanding of physics.* Thanks!
Watch this, may help ...
th-cam.com/video/nnkvoIHztPw/w-d-xo.html
Him: It's been said that the Planck length is the smallest length, but that's not the entire tale, as I will tell you in this week's episode of sub, sub, Subatomic Stories.
Me: Good one, Don!
This channel is GREAT! As a casual, trying to figure out reality this sort of info is a great roadmap for me. Thank you!
Lucky for me, I watched Sean Carol's video about exactly that!
Let's see, something like if the space is expanding faster than a particle can move through it, that particle will actually lose energy to the expansion. Photons red shift, electrons slow down.
If Einstein's GR only works in the macro world, how do we know microscopic black holes exist?
One of the alleged difficulties of producing a so-called quantum gravity theory is due to the Heisenberg's uncertainty principle.
To probe ever tinier distances, we need ever greater energies. The problem is that if you concentrate too much mass in a tiny space, the gravity of such a space becomes so huge that black holes form, making the measurement impossible.
This is my question. How do we know that a huge energy allocated to a tiny subatomic region of space would create a black hole, since there is no quantum gravity theory to go by?
How do scientists know, what are they basing this idea on, to say that a huge subatomic concentration of energy would lead to a microscopic black hole?
That was fascinating, and I'm really looking forward to the next new chapter. Thank you.
What?! Dr Don, you haven't always had a mustache?
My mom made me shave it when I was a baby.
Dear friend in Physics of the Universe!
I am enlightened by your illustrative videos and FermiLab's (USA's) Scientific contributions to the Humanity 💐❣️🙏
Absolutely thank you so much and the whole staff of the FermiLab, USA.
You are all great support to all the Human beings in all countries/ nations of the world 🌎🤗🌍🌄
If we send one of the Quantum entanglement particle to Black Hole they are still entaglement?
Well, I am fellow teen little to answer, But I can say entangled particles cohere as they interact with environment, and even measurements
@@divyanshvishwkarma9548 And my english is to weak to write this good but I think that entanglement is above time and space. And even event horizon is no barrier for this.
Conditions under the event horizons changes a lot, for instance Space and Time swapping their role (or properties to say)
And any event that occurs under event horizon doesn't have any effect on an outside observer,
And I am not a physicist now but can say that the monster will either break the entangled, or if it didn't, only a clever experimental physicist can find it😁😁
@@divyanshvishwkarma9548 That I wrote: "entanglement is above time and space"
man id love to see a crossover between fermilab & pbs spacetime. this was a cool episode by the way. got me thinking about the planck length.
Cannot believe you actually got out “astrophysicist are known to be dull and not funny “ without Neil deGrass Tyson cutting you off and telling his side instead!!! Lol
neil deGrass Tyson is annoying. Anyone who likes doing TED videos is a tool.
"... I know you didn't ask me, but..." ;)
I really appreciate what Neil deGrasse Tyson does and did for the public awareness of science, though I do think he took it a bit too far. His podcasts with Chuck Nice are some of the unfunniest things I've ever seen.
I'd love to see more in-depth videos from him, which are lacking lately. When he's able to put his ego aside, he's a great communicator.
@@ThelemicMagick true, what you said I agree. I can't stand watching Neil, nothing I saw I liked, but its what appeals to the masses is most important.
Its like donald trump for conservatives/racists/2nd amendment gun toters.
Same goes with left leaning liberal idiots/sjw dimwits/snowflakes.
Of course its not this serious, etx, but the idea is the same, the underlying truth about society, and the mass population is the same: fickle like anything, band wagon jumpers. I wish we had good leaders, moral leaders, and role models. I'd vote Dr. Lincoln as one.
Thanks Dr. Lincoln. This episode was very instructive.
This series are good for learning in the simplest way possible.
Dr. Don Lincoln: astrophysicists aren't funny.
Neil deGrasse Tyson: hold my beer.
He isnt an astrophysicist. When was the last time he did any real science? decades ago. For the most part his contributions are posting self-important tweets.
@@rykehuss3435 Agreed, Neil deGrass Tyson is annoying. Anyone who likes doing TED videos is a tool.
If Einstein's GR only works in the macro world, how do we know microscopic black holes exist?
One of the alleged difficulties of producing a so-called quantum gravity theory is due to the Heisenberg's uncertainty principle.
To probe ever tinier distances, we need ever greater energies. The problem is that if you concentrate too much mass in a tiny space, the gravity of such a space becomes so huge that black holes form, making the measurement impossible.
This is my question. How do we know that a huge energy allocated to a tiny subatomic region of space would create a black hole, since there is no quantum gravity theory to go by?
How do scientists know, what are they basing this idea on, to say that a huge subatomic concentration of energy would lead to a microscopic black hole?
@@rykehuss3435 Tyson is hawt,but Not a real scientist
Thanks. FINALLY! Someone that doesn't spew nonsense that the Planck length is the end all to be all. Important? Yes. The answer to what is below that length? To be determined using math not invented yet. Cheers.
Why is Brian May a disciple of Kansas? He made a study of Dust in the wind.
Howdy. Agreed and very funny! I looked at his Paper and am amazed! To say or type anymore will REVEAL my idioticy. Thanks for helping me laugh! Cheers
VINCE BERNAL TH-cam done right, glad for giggles
Spin of Indivisible Particle : Watch...
th-cam.com/video/nnkvoIHztPw/w-d-xo.html
Dr. Don, you were a bit shaken last time, but I am glad you got your composure back.
Lmao standup comedy as part of your PhD 😂
PhD thesis defense. It is a thing.
I just discovered your channel and subscribed! I'm excited for your upcoming videos.
Hi, great video. Has anyone suggested the dark photons as candidates for the hidden variables proposed by Eisten to overcome quantum mechanic uncertainty?
Awesome video Don! Thanks a lot for sharing! You have a great sense of humor! It's very fun to watch your videos!
scientists: "Energy is not conserved"
Me: I been lied to my whole life...
Seriously, down with normal "education" and the established media, we all need to get our info from the SAUCE
It still holds well enough in contexts where general relativity doesn’t have to be taken into account. It is still very useful.
joaquin vega Conservation of energy is still the best rule to follow for nearly every phenomena you can see in your everyday life. Especially if an investor aproaches you with his idea about infinite free energy...
Sure. Everyone should be taught general relativity in first grade. The fact that the kids can't even add yet shouldn't stop them from solving the Einstein field equations.
@Michael Bishop Could they have solved the EFE after that? Or any PDE? Or even ODE?
your shows are the best, love how you explain things tha twork. you should do a live show some time so people can ask you questions directly. thank you for the show.
Finally, someone explained what's actually going on with the plank length. The way that the plank length came from a hodge-podge of the Standard Model and gravity and yet was also said to be the smallest distance with 100% certainty always didn't make sense to me.
Your reading choices on the left side (behind you) are very interesting.
Also, regarding your comments on energy conservation, if you consider a photon is just an spacial aperture to a big bang temperature and expanding space changes the wavelength of that expression, it is easy to understand that the core energy of the photon has not changed, only the spacial apertures' behaviour of collapse has changed.
B-)
Planck has held the field longer than General Relativity, and Special Relativity. That's quite an accomplishment.
He doesn’t get nearly enough credit for his accomplishments. Everyone talks about Einstein, who got his ideas from Planck and Maxwell ( Among others).
Doesn't quantum entanglement disprove relativity ?
It's critical what you said at 5:52 about the Planck length not necessarily being the shortest size, it's just where current physics breaks down. I haven't heard a physicist saying that before but it makes perfect sense to me.
Seems the problem is about the basic definition of reality, reality is being defined as that which can be measured which is fine for all practical purposes but should reality be limited to our ability to measure?
Could there be particles too small to measure or have any impact on our physical universe?
Wonderful video as usual. I sometimes forget the human drama behind the story of physics, both are fascinating
Dr don you are exactly what I needed
Your sense of humor is top notch😂😂👍👍
Dr Don, the videos are just getting better and better, thank you for the great information and humor :)
And, Americans, you should vote this guy your president !
This is a great channel, the questions from the viewers are also awesome. Recently subscribed.
I noticed several years back that a photon with a wavelength of a planck length would have just exactly enough gravity to trap itself in a resonant orbit at a diameter of the planck length. It is the only wavelength of any photon where the mass equivalent and swartzchild radius converge as smaller wavelength photons would have a larger swartzchild radius and longer ones would have a shorter swartzchild radius. It seems that any photon with a wavelength smaller than the planck length would have a mass great enough that it would be some kind of singularity.
1. The mass of photons is _zero_ regardless of their wavelength. You must be talking about “relativistic mass” which is an outdated, deprecated concept. See also: ”Fermilab: Is relativistic mass real?” th-cam.com/video/LTJauaefTZM/w-d-xo.html
2. Objects do not “have gravity”; gravity is an *interaction* between several objects/particles.
3. The term is “ _Schwarzschild_ radius”: en.wikipedia.org/wiki/Schwarzschild_radius
4. It is possible in general relativity to have a black hole from energy that does not originally come from mass. When it comes from photons, it is called a “kugelblitz”, a special case of a geon: en.wikipedia.org/wiki/Kugelblitz_(astrophysics)
5. I wonder how you conclude from a wavelength to a particular orbit, but I will think about the possibility.
@@ThomasLahn I think what I should have said is that there is a certain planck scale wavelength photon that would trap itself in resonance at its own Swarzschild radius where the diameter is an integer of the wavelength/2. I think it is 2pi planck length. For all other photons with shorter or longer wavelengths, the wavelength and Swartzchild radii diverge dramatically.
@@mertonhirsch4734 The _SCHWARZSCHILD_ radius is given by
rₛ = 2 G M/c² = 2 G E/c⁴,
where I have applied M = E/c² to obtain the mass equivalent to a given energy (this semiclassical approximation works well for gravitational redshift by white dwarfs, so maybe here, too.)
A photon whose wavelength is the Planck length lₚ ≈ 1.6163 × 10⁻³⁵ m has the energy
E = ℎ f = ℎ c/λ = ℎ c/lₚ ≈ 12.29 GJ.
[This corresponds to hard gamma rays.]
Therefore, the Schwarzschild radius of such a photon would be
rₛ
= 2 G ℎ c/(c⁴ lₚ)
= 2 G ℎ/(c³ lₚ)
≈ 2.031 × 10⁻³⁴ m
≈ 12.57 lₚ.
So you can see that the Schwarzschild radius would be considerably greater than the Planck length.
You appear to think that the wavelength of a photon would have to do with the space that it occupies. But (AFAIK) that is not so. Photons are elementary particles, assumed as point-like, and we cannot tell exactly where they are (Heisenberg uncertainty relation: σₓ σₚ ≥ ℏ/2). They are not in any orbit (the Bohr model already fails to describe electrons; it surely fails for photons); we can only calculate probabilities of them being detected for regions where we want to detect them.
Only if, for some reason, the photon would be constrained inside a radius that is much smaller than its own Schwarzschild radius, then it would be a kugelblitz and a microscopic black hole with a fuzzy event horizon (since the position of the photon and its wavelength would be uncertain) would form around that region (assuming that GR would be applicable).
But then the photon would still not be orbiting anything: inside that radius, all geodesics point inward, and since it is already at the singularity that it created, it would be stuck, and it is questionable whether it could even exist as there are no photons at relative rest. On the other hand, such a microscopic black hole would evaporate in 1.18814 × 10⁻³⁷ s (if Hawking is correct; calculated with Viktor T. Toth’s Hawking radiation calculator), so it is not clear what would happen (does the photon continously regenerate black holes as it is trapped in that region?). A theory of quantum gravity is required here.
Also, you have to consider that for the photon to be constrained to that region, an enormous amount of energy (namely at least the energy of the photon again; see above) would be necessary in addition to the energy that it already has. If I understood Don Lincoln’s video “The Origins of Mass” correctly, that energy would be added to that system, at least doubling the Schwarzschild radius.
Finally, try
jila.colorado.edu/~ajsh/bh/quiz.html#quiz
to clarify some misconceptions about black holes that you appear to have :)
@@ThomasLahn Just wanted to point out that the value you got: ≈ 2.031 × 10⁻³⁴ m is exactly 4pi x the planck length. I believe that I didn't use a planck length. I think that if you start with a 2 x planck length photon you get a 2pi planck length S.C. radius.
@@mertonhirsch4734 No, the Schwarzschild _radius_ of that photon is _approximately_ 4π lₚ, and you argued _2_ π lₚ for the _circumference_ of its orbit (no doubt based on the Bohr atomic model and de Broglie wavelength of electrons) before. Seeing seeming relations in and between numbers, especially when irrational numbers are involved, after the fact, by careless rounding, is numerology, not science. See also:
en.wikipedia.org/wiki/Kees_de_Jager#Cyclosophy
Bohr (and Sommerfeld) were wrong: Electrons are not orbiting in circles with radiuses corresponding to their (de Broglie) wavelengths (or in ellipses); neither are photons. And light is not orbiting black holes at the Schwarzschild radius, but further out (you should have taken the quiz). Your idea does not add up.
Regarding the question of Nick Fontaine about the super strong cable that lowers a camera below the event horizon: the event horizon is not some kind of dark velvet curtain that covers the singularity from our eyes. It's the surface at which the gravity created by the singularity requires faster-than-light escape velocity. And below the event horizon the gravity is even stronger, so the escape velocity is even higher. As a result, the inside of the black hole must be also black, provided that it's a simple non-rotating black hole. If it does rotate, then it's not so obvious what's inside. For knowing more, I recommend the excellent PBS Spacetime youtube channel.
Excellent Video, Don !!
Dr, Lincoln : My avocation is physics (particle) but not my vocation. I am saying and asking this simply for an elementary explanation of the latest breakthroughs that you may know regarding fusion energy - NASA seems to indicate advances are being made but that is all I could ascertain as to what they have found. Any ideas ?
All quantities can be measured with just two basic units: the second, s, and the electronic charge, e. Both distances and time intervals between events can be measured in units of the second. Energy, momentum, mass, acceleration, temperature and frequency can all be measured in units of the reciprocal of the second, s⁻¹. The speed of light in vacuum, entropy and angular momentum are dimensionless in these units.
Speaking of black hole secrets.. is it possible to send out a message from inside the event horizon via gravitational waves? For instance, if two black holes are orbiting each other closely, they would form a single event horizon but you can maybe modulate frequency/amplitude of the gravitational waves and thus send a message out?
May I suggest to put the thing you read from a bit further away from the camera and a bit closer in line with the camera sight. In that way it becomes less obvious you read lines which shows in the eye movement and makes it more natural by creating the perception you look at the viewer while talking. Improving production quality and such.
Just out of curiosity, at what location do you think text is located?
@@donlincoln1961 I guess from your perspective on the left side of the camera, maybe less than two meters away.
@@disruptivetimes8738 Interesting. That's not where the teleprompter is.
@@drdon5205 Then I apologize for my wrong assumption.
We've learned two things from Brian May's work: 1) as long as your thesis doesn't take longer than 37 years to finish, you're not a slacker;
2) astrophysicists quote Kansas lyrics in their theses. (If you want Disney lyrics, you have to look to particle physicists).
Thanks Don, for answering my query. Indeed you have a great sense of humor and it would have been great to see you in the Big Bang Theory series.
I learned something nifty today! So now I get to talk about a fun weird little bizarre fact about the Planck units. When you start looking at the extended list of DERIVED Planck units, you come across one that makes you scratch your head a bit. It certainly made me scratch mine!
It's called the Planck resistance, and it comes out to be... 30Ω. Thirty ohms. For someone who used to be quite firmly in the camp of believing the planck units were the absolute physical limits of things (the smallest, the least massive, the hottest, the whateverest), this baffled my electrical engineery brain! There's resistances that can be considerably smaller and bigger than this planck resistance! So what gives!?!?
Turns out it's just the number that comes out in the wash when you combine the planck units in the same way that the ohm is defined. It's nothing more special than the resistance that is defined by the fundamental constants of nature, when those constants are taken to equal 1 unit of whatever thing they define. This little subatomic story enlightened me tonight and made me realize what should have been obvious this entire time. :)
Physics Explained has a great video on Planks lengths, apparently nothing can be closer to each other than this lenght otherwise black hole forms, and since even light can't escape black hole we can't retrieve any meaningful information from it; so maybe smaller things exist we just have no means to detect it on such scale
About that “conservation” point. My hair stood up like Planck’s. Holy zorblatts, Doc!
Thank you sir . Your work is always great . Love from India 🇮🇳
1:18. The “proof Quantum mechanics can blow your mind”got an instant thumbs up.
Quantum Mechanics - watch...
th-cam.com/video/UymZR_N4GIM/w-d-xo.html
Isn't possible to see the lost of energy of the photon going through expanding space as just being diluted on more "space" ? the energy is still there but on a larger area thus the bigger wavelength ?
I believe energy is always conserved however we humans simply haven't worked out the kinks yet
How is energy transferred to space and time to create the curvature of such
As the universe expands it red-shifts light. That reduces the energy of the light. Has anyone calculated if energy was conserved then the intensity of the microwave background would be higher. But that would also mean that one photon of energy leaving would result in more photons at the destination.
@@LaserFur light is an excitation of a field, if the field expand with the universe, isn't it normal for a vibration to expand too ? Thus the energy is locally lower because it spread across a bigger region ??
@@Tutul_ not counting the normal divergence of the light or dust along the path. The expansion of space itself lowers the wavelength. At a detector it measures less energy, but yes that energy would be over a longer period of time. So energy is conserved in this case.
@@LaserFur I think you misunderstand me or I missexplained it
The pictures joke was actually fantastic.
Thank you, I've noticed that this misconception is often floating around. Are there any ideas for how we could measure things at smaller scales? (I have a hypothesis that what we think of as point particles may be solid objects with diameters far shorter than the planck length)
A great program and great effort and a great presenter. Small comment. Energy is conserved not because of Noether theory. It is conserved because momentum is conserved or the world is symmetric, from which energy conservation is derived. E=(1/m) integral(mv.dmv)=.5 m v^2. Regards.
Just fantastic. Thank you very much.
THANK YOU PROFESSOR LINCOLN...!!!
Great video. Helped a lot. Thank you
That before and after pic of Planck's contribution to QM had me rolling!
As always, great video! Thank you!
Please address the lack of a theory of quantum measurement. That is, why is there no formula for the collapse of the wave function.
Thanks for your series. Excellent.
You are an amazing educator. Thank you so much for bringing all this amazing wondrous content and presenting it in a way that I can understand at least some of it! Lol! I wondered if there might be a chance to cover ‘Wigner’s Friend’ please and any more recent developments on this? Once again, Thank you hugely!
Hi Don
Are zortblats defined in terms of scroungknewts and feffphrittminskitts?
Or do you just normalize the units.
Thanks!
;)
1:04 Prof Lincoln you're the best.
Does a single particle have gravity (bends spacetime?), or is there a "tension" in spacetime that needs a minimum mass concentration for it to bend?
Current thinking is one particle is enough.
@@drdon5205 Thank you Dr. Don. If you can add anything, like how we know it and how we could measure it, I am all ears ;-)
Why are you always so worried about how much time an episode takes ? Longer episodes like 20min+ would be amazing!
BTW, Paul M Sutter, astrophysicist has a TH-cam channel that talks about astrophysics and physics in general, and quite fun person in his channel.