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	2022-11-23: How To See Black Holes By Catching Neutrinos 04:10: See, the speed of light is reduced in any medium inside a vacuum.
	2022-10-12: The REAL Possibility of Mapping Alien Planets! 19:23: ... the electron charge squared divided by 4pi time   the vacuum permittivity the Planck constant times the speed of light. If the ...
	2022-09-28: Why Is 1/137 One of the Greatest Unsolved Problems In Physics? 03:28: ... electron is in Couloumbs,  the speed of light in meters per second, vacuum permittivity and Planck's constant also have their ...
	2022-08-24: What Makes The Strong Force Strong? 18:36: Those fields have positive and negative frequency modes that cancel each other out to leave a vacuum.
	2022-08-17: What If Dark Energy is a New Quantum Field? 00:36: ... mainstream physical explanation for dark energy is that the vacuum of space has a constant energy density. Empty space buzzes with random ... 03:22: Standard “cosmological constant” dark energy has omega -1. This is just what you get when you say that the vacuum has a constant energy density. 05:18: ... fluctuations. For example, it’s actually very difficult to get the vacuum energy to be very close to zero but not quite equal to ... 05:50: ... naive calculation for the energy of the vacuum gives you a number something like 120 orders of magnitude larger than ... 10:55: ... fields, it could potentially cancel out their predicted extremely high vacuum energy in a natural way, so that dark energy becomes the tiny residual ... 15:05: ... of the alchemists, the aether. In that you give us energy in the vacuum of the YouTube funding models. Helping us exponentially expand our ... 00:36: ... intense over time rather than having a constant density expected of a vacuum energy. That would cause the universe to eventually tear itself apart on a ... 05:18: ... fluctuations. For example, it’s actually very difficult to get the vacuum energy to be very close to zero but not quite equal to ... 05:50: ... each other out. A perfectly symmetric canceling could get you down to a vacuum energy of zero, but it’s really really hard to cancel such a large number down ... 10:55: ... fields, it could potentially cancel out their predicted extremely high vacuum energy in a natural way, so that dark energy becomes the tiny residual from ...
	2022-06-22: Is Interstellar Travel Impossible? 19:30: Hawking’s original argument talked about perturbing the positive and negative frequency modes of the quantum vacuum.
	2022-06-15: Can Wormholes Solve The Black Hole Information Paradox? 03:20: ... swallowing and emitting virtual particles. We can think about the vacuum   of space as being filled with a boiling flux of  ...
	2022-05-25: The Evolution of the Modern Milky Way Galaxy 18:10: ... There would indeed be an additional effect  due to the tiny vacuum energy inside   the galaxy. However the effect is minuscule, ...
	2022-04-27: How the Higgs Mechanism Give Things Mass 07:33: ... then the field just sits at the lowest  point. We call that the vacuum ... 11:37: ... transition from the central bump to  the valley is an example of vacuum decay,   and we saw how this can lead to the creation  of ... 11:56: ... two reasons. The first is that the lowest   energy state - the vacuum state - isn’t where the  field strength is zero. This is called a ... 12:26: ... weird thing: there’s not just a single  vacuum state - there’s a rin g of valid states.   The universe will ... 14:54: ... this happens because of the non-zero  vacuum state of the Higgs field. That little   bit of Higgsiness ... 11:37: ... transition from the central bump to  the valley is an example of vacuum decay,   and we saw how this can lead to the creation  of cosmic strings in ... 11:56: ... the  field strength is zero. This is called a non-zero   vacuum expectation value. The original massive  particles of the field now oscillate ... 07:33: ... then the field just sits at the lowest  point. We call that the vacuum state. ... 11:37: ... has reached the base of this  new minimum we have a new stable vacuum state. ... 11:56: ... two reasons. The first is that the lowest   energy state - the vacuum state - isn’t where the  field strength is zero. This is called a ... 12:26: ... weird thing: there’s not just a single  vacuum state - there’s a rin g of valid states.   The universe will just ... 14:54: ... this happens because of the non-zero  vacuum state of the Higgs field. That little   bit of Higgsiness everywhere ... 11:56: ... two reasons. The first is that the lowest   energy state - the vacuum state - isn’t where the  field strength is zero. This is called a ... 12:26: ... weird thing: there’s not just a single  vacuum state - there’s a rin g of valid states.   The universe will just ...
	2022-02-23: Are Cosmic Strings Cracks in the Universe? 00:58: ... will always drop to the nearest minimum  in energy - this is the vacuum state of the field.   In the early universe, the Higgs field ... 04:51: ... the universe, the Higgs field started falling  towards the new vacuum state - we call this vacuum   decay. Neighboring points in a ... 05:59: ... but our  Higgs field formed strings. Remember   that the vacuum decayed in a random  direction towards this circular ... 07:33: ... the defect tighten as much  as they can. The filament of high vacuum energy is   squeezed it down to one-ten-trillionth the ... 08:50: ... travel between the nucleation event   and the completion of vacuum decay and then the  expanding universe stretched them up to the ... 12:19: ... that the universe is riddled with veins   of its primordial vacuum. If we can find one who  knows what we’ll learn? We may discover ... 08:50: ... travel between the nucleation event   and the completion of vacuum decay and then the  expanding universe stretched them up to the ... 05:59: ... but our  Higgs field formed strings. Remember   that the vacuum decayed in a random  direction towards this circular valley.   ... 04:51: ... the same part of the Higgs minimum.   A bubble of this lower vacuum energy was  nucleated, and it expanded at the speed   of light. ... 07:33: ... the defect tighten as much  as they can. The filament of high vacuum energy is   squeezed it down to one-ten-trillionth the width  of ... 04:51: ... the same part of the Higgs minimum.   A bubble of this lower vacuum energy was  nucleated, and it expanded at the speed   of light. Many ... 00:58: ... will always drop to the nearest minimum  in energy - this is the vacuum state of the field.   In the early universe, the Higgs field ... 04:51: ... the universe, the Higgs field started falling  towards the new vacuum state - we call this vacuum   decay. Neighboring points in a field ... 05:59: ... the valley. It   became a fossil of the ancient, high-energy vacuum  that would persists into the modern ... 04:51: ... field started falling  towards the new vacuum state - we call this vacuum   decay. Neighboring points in a field drag on each  other, pulling ...
	2022-02-10: The Nature of Space and Time AMA 00:03: ... new space in a sense um in this that that new space has the same vacuum energy density the old one has the same kind of behavior of virtual ...
	2021-12-20: What Happens If A Black Hole Hits Earth? 00:00: ... when I first learned about black holes I imagined these gigantic cosmic vacuum cleaners that must eventually suck up everything. They're not really ...
	2021-12-10: 2021 End of Year AMA! 00:02: ... think so i think so i think blue quantum gravity um can calculate the vacuum expectation value uh uh which would give us dark energy i don't know ...
	2021-09-15: Neutron Stars: The Most Extreme Objects in the Universe 02:35: ... this layer of haze starts out  very tenuous - almost a vacuum,   and then gets denser as we drop.  But the similarities end ... 03:27: ... back to. Once we’ve landed on the surface, our heads are in the vacuum   of space, while our feet are in a foggy plasma with a density many ...
	2021-09-07: First Detection of Light from Behind a Black Hole 12:46: And then the episode on how vacuum decay could destroy the universe .. or universes, if the ideas in the first episode are right. 14:25: ... von Schweinitz and TBE_pryce both commented that the vacuum decay scenario sounds a lot like the big bang - what with it producing ... 14:39: In fact cosmic inflation - the event that many physicists put the bang in the big bang - IS a type of vacuum decay. 15:03: ... means a new vacuum decay event now wouldn’t yield universe whose interior is expanding ... 15:34: How big does the vacuum decay bubble need to be in order to propagate. 15:42: ... us that it depends on the energy difference between the false and true vacuum - presumably the bigger the difference the smaller the bubble needs to ... 12:46: And then the episode on how vacuum decay could destroy the universe .. or universes, if the ideas in the first episode are right. 14:25: ... von Schweinitz and TBE_pryce both commented that the vacuum decay scenario sounds a lot like the big bang - what with it producing an ... 14:39: In fact cosmic inflation - the event that many physicists put the bang in the big bang - IS a type of vacuum decay. 15:03: ... means a new vacuum decay event now wouldn’t yield universe whose interior is expanding quickly - ... 15:34: How big does the vacuum decay bubble need to be in order to propagate. 15:03: ... means a new vacuum decay event now wouldn’t yield universe whose interior is expanding quickly - in the ... 14:25: ... von Schweinitz and TBE_pryce both commented that the vacuum decay scenario sounds a lot like the big bang - what with it producing an expanding ...
	2021-08-18: How Vacuum Decay Would Destroy The Universe 00:00: ... is going to end. But of all the  possible ends of the universe vacuum decay   would have to be the most thorough - because  it ... 01:00: ... the laws of physics across the universe.   That mechanism is vacuum decay, and  some physicists think it’s ... 05:03: ... true minimum - the true lowest energy, or what we call the true vacuum. This is where the field would   prefer to spend its time given ... 05:43: ... I’ll get to. But what if the   entire universe is in the false vacuum? Then a tunneling event would be a little more ... 06:08: ... a universe filled with the Higgs field in a false vacuum. At a single point in space,   a quantum tunneling event drops ... 07:01: ... Higgs field through the entire universe   down into the true vacuum. This is vacuum decay. It’s a phase transition of the quantum ... 08:08: ... let’s review the horrors that  would result from vacuum decay.   First up, everything gets fried. The energy  ... 08:30: ... Those masses depend on the energy in the field - the so-called vacuum expectation   value. Drop the energy in the field and ... 09:15: ... we really   are living in one of these nasty false  vacuums - then we’ll talk about whether   that vacuum might decay. ... 09:38: ... of these masses tell us that … we are probably in the false vacuum - but we’re actually very close to the boundary. We   ... 10:10: ... there’s only a very small probability  that a bubble of true vacuum will randomly form   that’s large enough to actually ... 11:34: ... it’s very unlikely  that a vacuum decay bubble   will reach us in the lifespan of our ... 12:07: ... this leads to one more comforting fact. If the vacuum does decay inside our cosmic horizon   we’ll never see it ... 09:38: ... of these masses tell us that … we are probably in the false vacuum - but we’re actually very close to the boundary. We   MIGHT ... 01:00: ... the laws of physics across the universe.   That mechanism is vacuum decay, and  some physicists think it’s ... 08:30: ... should also   add that there are other possible types  of vacuum decay beyond Higgs field decay.   For example, there may be weird ... 11:34: ... it’s very unlikely  that a vacuum decay bubble   will reach us in the lifespan of our species,  ... 01:00: ... the laws of physics across the universe.   That mechanism is vacuum decay, and  some physicists think it’s ... 11:34: ... it’s very unlikely  that a vacuum decay bubble   will reach us in the lifespan of our species,  let alone your own ... 07:01: ... the entire universe   down into the true vacuum. This is vacuum decay. It’s a phase transition of the quantum fields.   In fact it has a ... 00:00: ... is going to end. But of all the  possible ends of the universe vacuum decay   would have to be the most thorough - because  it could totally ... 08:08: ... let’s review the horrors that  would result from vacuum decay.   First up, everything gets fried. The energy  released in the decay ... 12:07: ... time we have left - perhaps   mere billions of years - before vacuum decay swallows this fragile and metastable space ... 08:30: ... Those masses depend on the energy in the field - the so-called vacuum expectation   value. Drop the energy in the field and you  reduce the masses of ... 01:15: ... to give you a crude picture - vacuum  decay looks like a bubble of annihilation   that expands at ... 10:54: ... that our giant particle  colliders like the LHC might nucleate a vacuum   decay bubble. But that was unfounded. After all, Earth is ... 10:10: ... so the next question is could the vacuum really decay? As long as decay is possible,   it’s inevitable. At any ... 09:15: ... we really   are living in one of these nasty false  vacuums - then we’ll talk about whether   that vacuum might decay. ...
	2021-05-25: What If (Tiny) Black Holes Are Everywhere? 02:06: ... - a brilliant workaround - to prove that if an event horizon forms in a vacuum, then the vacuum states of the quantum fields have to be ...
	2021-04-07: Why the Muon g-2 Results Are So Exciting! 07:43: The quantum vacuum is seething with an incredible variety of possible virtual particles.
	2021-03-09: How Does Gravity Affect Light? 09:46: The only thing that’s not relative is the speed of light - everyone observes the same local speed of light - 300,000 km/s in a vacuum.
	2020-12-22: Navigating with Quantum Entanglement 09:49: ... - ideally isolated systems of very few particles, perhaps in a vacuum or near absolute zero ...
	2020-11-18: The Arrow of Time and How to Reverse It 10:34: ... to be yes, at least to some degree. The Higgs field sits at a non-zero vacuum energy so could potentially decay to zero, or even to a lower non-zero ... 10:58: ... the universe went thorugh another phase transition - a vacuum decay - then the weak interaction would fundamentally change - to become ... 11:09: given we hgaven't actually done a vacuum decay eposide yet I'll save my deep dive into this for then. 11:16: ... Vacuum Diagrams dropped a lot of wisdom as always. I’m going to try to restate ... 10:58: ... the universe went thorugh another phase transition - a vacuum decay - then the weak interaction would fundamentally change - to become a ... 11:09: given we hgaven't actually done a vacuum decay eposide yet I'll save my deep dive into this for then. 10:58: ... the universe went thorugh another phase transition - a vacuum decay - then the weak interaction would fundamentally change - to become a ... 11:09: given we hgaven't actually done a vacuum decay eposide yet I'll save my deep dive into this for then. 11:16: ... Vacuum Diagrams dropped a lot of wisdom as always. I’m going to try to restate one point ... 10:34: ... to be yes, at least to some degree. The Higgs field sits at a non-zero vacuum energy so could potentially decay to zero, or even to a lower non-zero state ...
	2020-10-05: Venus May Have Life! 09:44: ... about how these spores can survive crazy conditions - including the vacuum of space and the extreme temperatures and pressures of meteor impact or ...
	2020-09-21: Could Life Evolve Inside Stars? 04:02: ... of the universe with different properties - for example, different vacuum ...
	2020-07-20: The Boundary Between Black Holes & Neutron Stars 02:00: ... Louisiana and the VIRGO observatory in Italy, consist of kilometers-long vacuum tubes set at right ...
	2020-07-08: Does Antimatter Explain Why There's Something Rather Than Nothing? 00:22: ... at all? Shouldn’t everything just have annihilated again, leaving only a vacuum bathed in ... 09:19: ... the coupling between the particles and the quantum fluctuations of the vacuum. Any difference in these properties in anti-matter versus matter will ... 00:22: ... at all? Shouldn’t everything just have annihilated again, leaving only a vacuum bathed in ...
	2020-06-08: Can Viruses Travel Between Planets? 08:53: ... space is deadly - it’s a freezing cold vacuum bathed in intense radiation.Virions are a bit like seeds or spores - ... 09:13: Take the tobacco mosaic virus - it can actually be crystalized, protecting it from desiccation, cold, and vacuum. 15:22: ... the Casimir effect is thought to be due to an alteration in the vacuum energy between a pair of conducting surfaces, which leads to those ... 15:49: ... agrees with so-called lifshitz theory, which is based on this altered vacuum energy ... 08:53: ... space is deadly - it’s a freezing cold vacuum bathed in intense radiation.Virions are a bit like seeds or spores - dormant ... 15:22: ... the Casimir effect is thought to be due to an alteration in the vacuum energy between a pair of conducting surfaces, which leads to those surfaces ... 15:49: ... agrees with so-called lifshitz theory, which is based on this altered vacuum energy ...
	2020-05-27: Does Gravity Require Extra Dimensions? 10:08: The experiment is now typically done in a vacuum, with precise temperature control and electrostatic and magnetic shielding. 11:58: This is the negative pressure due to the exclusion of quantum vacuum modes, or virtual particles, between two very closely separated plates.
	2020-05-18: Mapping the Multiverse 15:40: ... been performed with much higher precision using other methods - lasers, vacuum chambers, strange quantum mechanical states of light - you name ...
	2020-05-11: How Luminiferous Aether Led to Relativity 12:25: ... Paul Dirac suggested that a “particulate aether” could explain the near vacuum state of spacetime in which quantum physicists believe particle pairs ...
	2020-04-28: Space Time Livestream: Ask Matt Anything 00:00: ... body rotate itself minute do you want to tell us it can do it in vacuum I can do it can do it in you know outer space there are some amazing ...
	2020-04-22: Will Wormholes Allow Fast Interstellar Travel? 09:44: ... are brought very close together will block components of the quantum vacuum from existing in that region. The gap between the plates will then have ... 12:17: ... And there is one place natural wormholes might exist: in the quantum vacuum. This was another idea of John ... 15:35: ... 1 particle per cubic centimeter and 1 particle per cubic meter. It's vacuum-y enough to kill you fast, but there's enough of the stuff to produce, for ...
	2020-03-03: Does Quantum Immortality Save Schrödinger's Cat? 14:28: ... Oxon asks whether the double slit experiment is usually performed in a vacuum, and if not, why doesn’t interaction with gas cause immediate ... 14:43: ... disturbing them by interactions with the air - so most are done in near vacuum. ... 15:12: Remember the that first double-slit experiment was performed by Thomas Young in 1801 and there wasn't much in the way of vacuum technology.
	2020-02-11: Are Axions Dark Matter? 03:59: ... one thing, the vacuum in QCD is full of weird structure. You might ask how can a vacuum, aka ... 04:33: ... the vacuum can hop between these different states. But because they're all the same ... 05:16: ... it’s these new terms - the ones added by the weird vacuum - that appear to violate CP symmetry. That means the strong force should ... 03:59: ... the vacuum in QCD is full of weird structure. You might ask how can a vacuum, aka “nothing” have structure? Well, in quantum field theories, the vacuum ... 04:33: ... occupy all of those states at once. This bizarre structure for the vacuum alters the equations of motion that come from QCD, new terms get added and the ... 03:59: ... aka “nothing” have structure? Well, in quantum field theories, the vacuum isn’t really nothing. “Vacuum” is the word we use to describe the lowest ...
	2020-02-03: Are there Infinite Versions of You? 07:19: The constants of nature or the energy of the vacuum may well be different between regions. 08:10: It IS technically possible for the energy of the vacuum itself to have any value, even enormously large. 08:17: But universes with large vacuum energies will exponentially expand, until that vacuum energy decays to lower values in smaller regions within.
	2019-12-17: Do Black Holes Create New Universes? 07:16: ... forever then in the distant future, quantum fluctuations of that near vacuum will cause black holes to spontaneously appear - and given infinite time ...
	2019-11-11: Does Life Need a Multiverse to Exist? 09:29: ... problem is, when we try to calculate the strength of this vacuum energy from our theory we get an enormous number - 10^60 to 10^120 ... 09:49: If fact, that’s true if the strength of vacuum energy were only a little larger than is observed. 10:25: ... there are other theoretical ways to get the vacuum energy to take on different values in different regions of the universe ... 11:24: ... suggests that the values of the fundamental constants, including the vacuum energy, are set by the particular configuration of the extra coiled ... 12:04: ... and in each bubble the constants of nature - and especially the vacuum energy - taking on different ... 09:29: ... problem is, when we try to calculate the strength of this vacuum energy from our theory we get an enormous number - 10^60 to 10^120 larger than ... 09:49: If fact, that’s true if the strength of vacuum energy were only a little larger than is observed. 10:25: ... there are other theoretical ways to get the vacuum energy to take on different values in different regions of the universe - or in ... 11:24: ... suggests that the values of the fundamental constants, including the vacuum energy, are set by the particular configuration of the extra coiled dimensions ... 12:04: ... and in each bubble the constants of nature - and especially the vacuum energy - taking on different ...
	2019-11-04: Why We Might Be Alone in the Universe 09:40: That planet acts like a gigantic gravitational vacuum cleaner, absorbing a lot of the debris left over from the formation of the solar system.
	2019-10-21: Is Time Travel Impossible? 05:42: ... already produce this in the Casimir effect, in which the energy of the vacuum is lowered between two nearby conducting ... 11:17: ... fundamental law of physics that prohibits it - for example, the quantum vacuum may be unstable in the infinitely iterating loops of a closed timelike ...
	2019-09-30: How Many Universes Are There? 01:14: ... greater universe – or multiverse - is to expand exponentially due to the vacuum of space itself having a large and constant energy ... 06:19: ... an open and contentious question why the current energy density of the vacuum should be so low without being exactly zero given that it started out so ... 06:43: Here’s a possible explanation: what different bubble universes can end up with different vacuum energies? 06:51: ... low vacuum energies like ours might be extremely rare, but there are so many bubble ... 07:38: More than 10^500 possible vacuum states – probably a lot more. 08:01: We don’t know why our universe has the particular string vacuum state that it does. 08:24: All different vacuum states exist, and our universe necessarily has one that leads to life-friendly particles. 06:43: Here’s a possible explanation: what different bubble universes can end up with different vacuum energies? 06:51: ... low vacuum energies like ours might be extremely rare, but there are so many bubble ... 08:01: We don’t know why our universe has the particular string vacuum state that it does. 07:38: More than 10^500 possible vacuum states – probably a lot more. 08:24: All different vacuum states exist, and our universe necessarily has one that leads to life-friendly particles.
	2019-08-19: What Happened Before the Big Bang? 01:47: It had a nonzero vacuum energy. 03:43: Guth's idea is that there's a local minimum in potential energy that allows the inflaton field to get stuck in a false vacuum state. 06:17: As the universe cools, different vacuum states can appear possibly trapping the inflaton field. 01:47: It had a nonzero vacuum energy. 03:43: Guth's idea is that there's a local minimum in potential energy that allows the inflaton field to get stuck in a false vacuum state. 06:17: As the universe cools, different vacuum states can appear possibly trapping the inflaton field.
	2019-08-06: What Caused the Big Bang? 03:23: ... the upshot is that if the vacuum of space has a constant energy density, then Einstein's equations end up ... 03:42: The speed of that exponential expansion depends on the strength of the vacuum energy density. 04:13: ... do this, the energy density of the vacuum during inflation would need to be vastly stronger than dark energy. ... 04:32: So, the vacuum energy would need to drop from a very high value to basically zero. 04:48: QFT can explain how a vacuum can have energy, which - surprise surprise - we also covered in a playlist. 06:29: And by the way, the lowest energy state of a field is called its vacuum state. 07:06: We would call this a false vacuum and it gives us exactly the constant vacuum energy density needed for inflation. 07:13: There are other ways for a field to end up with a positive vacuum energy density and I'll come back to these. 08:16: ... field remains in a vacuum state that doesn't matches temperature - in the same way that water can ... 08:51: ... on that other side, it sees a deeper truer minimum - perhaps the true vacuum state - and suddenly starts to lose energy again racing towards that ... 09:07: ... point would also be dragged out of the local minimum towards the true vacuum and so the entire inflaton field would cascade down in ... 09:30: The inflaton field also undergoes a phase transition towards the new vacuum state. 10:39: So, the vacuum of inflation is converted into an extremely hot ocean of particles. 03:42: The speed of that exponential expansion depends on the strength of the vacuum energy density. 04:32: So, the vacuum energy would need to drop from a very high value to basically zero. 07:06: We would call this a false vacuum and it gives us exactly the constant vacuum energy density needed for inflation. 07:13: There are other ways for a field to end up with a positive vacuum energy density and I'll come back to these. 03:42: The speed of that exponential expansion depends on the strength of the vacuum energy density. 07:06: We would call this a false vacuum and it gives us exactly the constant vacuum energy density needed for inflation. 07:13: There are other ways for a field to end up with a positive vacuum energy density and I'll come back to these. 06:29: And by the way, the lowest energy state of a field is called its vacuum state. 08:16: ... field remains in a vacuum state that doesn't matches temperature - in the same way that water can become ... 08:51: ... on that other side, it sees a deeper truer minimum - perhaps the true vacuum state - and suddenly starts to lose energy again racing towards that ... 09:30: The inflaton field also undergoes a phase transition towards the new vacuum state. 08:51: ... on that other side, it sees a deeper truer minimum - perhaps the true vacuum state - and suddenly starts to lose energy again racing towards that ...
	2019-04-03: The Edge of an Infinite Universe 08:15: ... – past and future - where he could define the state of the quantum vacuum in solvable flat ... 08:37: He found that two “infinitely distant” regions could not both be in a perfect vacuum state if a black hole lay between them.
	2019-03-28: Could the Universe End by Tearing Apart Every Atom? 04:32: ... completely dominate the expansion so we have the energy density of the vacuum and the pressure that it exerts but now that pressure term is important ... 11:54: ... a plausible physical explanation for a constant dark energy that the vacuum has a set amount of energy per volume. There are at least some physical ...
	2019-03-20: Is Dark Energy Getting Stronger? 02:13: Mathematically we represent a constant vacuum energy with Einstein’s cosmological constant – or Lambda.
	2019-03-13: Will You Travel to Space? 13:58: Mark Segal and Pieces'O'Cake Maleck asked what if the cog part of the Brownian ratchet is in a vacuum? 14:28: So, what if the cog is in a vacuum, so there are no particles to turn it backwards? 14:38: ... particles will also have a lot of internal thermal vibration. Even in a vacuum, that internal vibration is enough to randomize its rotational ...
	2019-03-06: The Impossibility of Perpetual Motion Machines 08:41: One popular source of free energy is the zero-point energy of the quantum vacuum, and it’s the most fun to debunk. 08:48: ... going to have to refer you to our entire playlist on the quantum vacuum for the physics, but the important point is that any energy of the ...
	2019-02-07: Sound Waves from the Beginning of Time 12:26: It appears unchanging over time, just as we'd expect if dark energy is the energy of the vacuum itself.
	2019-01-30: Perpetual Motion From Negative Mass? 09:46: ... them all very badly, and has implications for the stability of the vacuum ...
	2019-01-09: Are Dark Matter And Dark Energy The Same? 02:18: The standard picture of dark energy is that it’s an actual greater-than-zero energy of the vacuum of space.
	2018-12-06: Did Life on Earth Come from Space? 00:37: ... to contend with near absolute zero temperatures extreme dryness a hard vacuum and probably worst of all some incredibly destructive radiation for up ...
	2018-11-07: Why String Theory is Right 15:26: More accurately, the conducting plates create a horizon in what would otherwise be a perfect infinite vacuum. 15:40: Those horizons perturb the vacuum which can lead to the creation of very real particles, as in Hawking radiation. 16:03: David Ratliff asks if a quantum tree falls in a vacuum and nobody is around to measure it, does it still have energy?
	2018-10-31: Are Virtual Particles A New Layer of Reality? 08:42: So that's the deal with virtual particles in particle interactions, but we also hear about the role of virtual particles in a complete vacuum. 08:52: ... might have heard the quantum vacuum described as his roiling ocean of virtual particle-antiparticle pairs ... 09:15: These modes also exist in the vacuum just without the excitations. 09:20: ... mode should have 0 energy in a vacuum, but in quantum mechanics, nothing can be so exact-- thanks, again, to ... 09:31: In order to remain "uncertain," there has to be a slight chance that when you look at a vacuum, any given mode will have non-zero energy. 09:48: So there's a chance that when measured the vacuum will appear to have energy and so have particles. 10:00: Or more to the point, do vacuum fluctuations produce actual particles when there's nothing else around? 10:12: In the math of QFT, the perfect vacuum is a steady state. 10:27: ... into one of these possibilities when something interacts with the vacuum. ... 10:42: This is a pretty subtle point, but it makes a huge difference in how we think about the vacuum. 10:53: Instead, they're fanciful way of talking about what might happen if something interacts with the vacuum. 11:28: In his actual mathematical derivation, he instead talks about vibrational modes of the quantum vacuum being cut off by the event horizon. 11:37: This disturbance of the vacuum generates particles. 11:40: But without the black hole, the vacuum stays a vacuum. 11:44: A similar perturbation of the quantum vacuum is also seen in the Casimir and Unruh effects. 08:52: ... pairs popping into and out of existence, the so-called vacuum fluctuations or zero point ... 10:00: Or more to the point, do vacuum fluctuations produce actual particles when there's nothing else around? 11:37: This disturbance of the vacuum generates particles. 11:40: But without the black hole, the vacuum stays a vacuum.
	2018-10-25: Will We Ever Find Alien Life? 14:52: Well, I'm going to quote Vacuum Diagrams on this one.
	2018-10-10: Computing a Universe Simulation 13:04: Light traveling through space is slowed down from the full light speed of the perfect vacuum.
	2018-10-03: How to Detect Extra Dimensions 07:39: This is usually thought of as coming from the action of the energy of the vacuum. 15:30: [INAUDIBLE] Vacuum Diagrams, Gareth [INAUDIBLE] complaining-- they just keep at it.
	2018-09-20: Quantum Gravity and the Hardest Problem in Physics 15:01: VoodooD0g points out that the vacuum isn't really empty, what, with all the virtual particles popping into and out of existence. 15:27: No real quantum states means no information except, perhaps, whatever information you need to track the bulk properties, like vacuum energy. 15:01: VoodooD0g points out that the vacuum isn't really empty, what, with all the virtual particles popping into and out of existence.
	2018-08-23: How Will the Universe End? 12:23: Vacuum decay may drop the universe to an even lower energy state, wiping out the laws of physics as we know them. 14:49: QED further tweaks this by showing the charge can smear by something called the vacuum polarization. 12:23: Vacuum decay may drop the universe to an even lower energy state, wiping out the laws of physics as we know them. 14:49: QED further tweaks this by showing the charge can smear by something called the vacuum polarization.
	2018-07-18: The Misunderstood Nature of Entropy 09:12: ... it on a particular spot to construct a special microstate or to use a vacuum pump and a glass wall to move all of the air to one side of the ...
	2018-04-11: The Physics of Life (ft. It's Okay to be Smart & PBS Eons!) 11:07: ... Vacuum Diagrams points out that from the point of view of an inertial observer, ...
	2018-04-04: The Unruh Effect 01:00: As we saw in our episode on horizon radiation, the presence of horizons distorts the quantum vacuum in a way that can create particles. 06:00: And just as with Hawking radiation, that horizon cuts off your access to certain fundamental frequency modes of the quantum vacuum. 06:36: The vacuum should appear warm with a temperature proportional to the acceleration. 07:06: ... patch of space filled with radiation, but the latter will see an empty vacuum in the same ...
	2018-03-15: Hawking Radiation 01:54: ... appear and then annihilate each other, briefly borrowing energy from the vacuum ... 03:51: ... a quantum field is in a vacuum state, there's a balance between positive and negative frequency modes, ... 04:18: Horizons cut off access to certain modes of the quantum fields, disturbing the balance that defines the vacuum. 05:21: Hawking imagined a simple quantum field tracing this path, a field that is in a perfect vacuum state before the formation of the black hole. 05:28: But he found that the close shave with the black hole disturbs the fundamental vibrational modes that define the fluctuations of the vacuum. 05:54: ... allowed him to compare the state of the vacuum in two regions of flat space far from the black hole, regions where the ... 07:04: With the loss of certain fundamental modes, the vacuum state must be constructed from the remaining modes. 07:10: That distorted vacuum looks like it's full of particles. 09:19: The vacuum should look like a vacuum. 03:51: ... a quantum field is in a vacuum state, there's a balance between positive and negative frequency modes, which ... 05:21: Hawking imagined a simple quantum field tracing this path, a field that is in a perfect vacuum state before the formation of the black hole. 07:04: With the loss of certain fundamental modes, the vacuum state must be constructed from the remaining modes. 05:54: ... of flat space far from the black hole, regions where the nature of vacuums, quantum fields, and particles are perfectly well ...
	2018-03-07: Should Space be Privatized? 12:18: ... [INAUDIBLE] laughs at physicists with their frictionless trebuchets in a vacuum, while Don Sample suggests we start by assuming a spherical ...
	2018-01-24: The End of the Habitable Zone 10:49: Last week we talked about how slicing a piece out of space time caused different observers to disagree on the nature of the vacuum. 11:14: The vacuum state of all fields are redefined in the vicinity of a black hole or for an accelerating observer. 12:32: But in short, it involves calculating the state of the vacuum before the black hole formed and then again after it formed. 12:38: In order for the two states to be consistent, the after vacuum state has an excess of positive energy modes. 11:14: The vacuum state of all fields are redefined in the vicinity of a black hole or for an accelerating observer. 12:38: In order for the two states to be consistent, the after vacuum state has an excess of positive energy modes.
	2018-01-17: Horizon Radiation 00:46: And for two observers with very different, but constant speeds-- inertial observers, the vacuum itself should appear the same. 01:45: As it turns out, what gives is the nature of the vacuum, and in fact, the notion of what a particle is becomes observer dependent. 01:53: ... of which are very similar and are results of this observer dependent vacuum. ... 02:22: ... get at this idea of observer dependent particles and vacua, we're going to need some quantum field theory, and we're going to need ... 03:44: ... frames in a way that leaves the laws of physics and the nature of the vacuum ... 03:55: ... the laws of physics, they find they have to redefine the nature of the vacuum, ... 04:08: To see how this happens, we need to think about how particles, interactions, and vacuums are described in quantum field theory. 06:59: Now it starts out with no oscillations, analogous to the vacuum state in quantum field theory. 09:13: But there's no such restriction for the creation and annihilation operators it's made of, and it's these operators that define the vacuum. 09:22: As discussed in a previous episode, we can think of the vacuum as a sea of virtual particles. 09:35: Infinite spatially undefined particles with defined momenta, and these just happen to cancel each other out, leaving 0 particles or a vacuum. 10:51: Now when you use the new, rejigged field operator to describe the vacuum, some momentum modes that once canceled out no longer cancel out. 11:01: What was once a vacuum now has particles. 11:20: The vacuum acquires a non-zero temperature. 11:39: Now we've already seen how this effect reduces the energy of the vacuum between conducting plates. 11:20: The vacuum acquires a non-zero temperature. 03:44: ... frames in a way that leaves the laws of physics and the nature of the vacuum intact. ... 06:59: Now it starts out with no oscillations, analogous to the vacuum state in quantum field theory. 04:08: To see how this happens, we need to think about how particles, interactions, and vacuums are described in quantum field theory.
	2017-12-06: Understanding the Uncertainty Principle with Quantum Fourier Series 01:19: The vacuum itself can be thought of as constructed from the sum of infinite possible particles. 11:01: ... these spatially infinite particles, that we can describe how the quantum vacuum changes to give us phenomena like Unruh and Hawking radiation, which you ...
	2017-11-29: Citizen Science + Zero-Point Challenge Answer 06:00: There were two, both quizzing you on the zero-point energy of the quantum vacuum. 06:06: The first question was about practical uses of the quantum vacuum. 06:57: ... a simplistic theoretical estimate of the vacuum energy density comes from assuming that there are no virtual photons ... 07:06: ... frequency corresponding to a photon with the Planck energy, you get a vacuum energy density of a ridiculously high 10 to the power of 112 ergs per ... 07:18: In this theoretical estimate, vacuum energy density is proportional to the fourth power of cutoff frequency. 07:59: And if vacuum energy is proportional to the fourth power of cutoff frequency, then this equation gives the relationship we need. 08:07: There are a bunch of constants in the cutoff frequency vacuum energy relation, but they cancel out. 08:13: That ratio of vacuum energies is 10 to the power of 120. 08:32: ... the right maximum virtual photon frequency definitely can't give us the vacuum energy that we see as dark ... 08:13: That ratio of vacuum energies is 10 to the power of 120. 06:57: ... a simplistic theoretical estimate of the vacuum energy density comes from assuming that there are no virtual photons above a ... 07:06: ... frequency corresponding to a photon with the Planck energy, you get a vacuum energy density of a ridiculously high 10 to the power of 112 ergs per ... 07:18: In this theoretical estimate, vacuum energy density is proportional to the fourth power of cutoff frequency. 07:59: And if vacuum energy is proportional to the fourth power of cutoff frequency, then this equation gives the relationship we need. 08:07: There are a bunch of constants in the cutoff frequency vacuum energy relation, but they cancel out. 08:32: ... the right maximum virtual photon frequency definitely can't give us the vacuum energy that we see as dark ... 06:57: ... a simplistic theoretical estimate of the vacuum energy density comes from assuming that there are no virtual photons above a certain ... 07:06: ... frequency corresponding to a photon with the Planck energy, you get a vacuum energy density of a ridiculously high 10 to the power of 112 ergs per centimeter ... 07:18: In this theoretical estimate, vacuum energy density is proportional to the fourth power of cutoff frequency. 08:07: There are a bunch of constants in the cutoff frequency vacuum energy relation, but they cancel out.
	2017-11-22: Suicide Space Robots 10:42: ... past couple of episodes have continued discussion of the quantum vacuum and zero-point energy, including some discussion of the pseudoscience ... 11:30: And just quickly regarding the objections of vacuum diagrams to some of my statements in this whole quantum vacuum series-- doctor diagrams, vacuum. 11:39: May I call you vacuum? 12:00: You say that quantum field theory makes no prediction about the energy of the vacuum. 12:12: QFT may not make a prediction about the zero-point energy, but it does predict the existence of a fluctuating quantum vacuum. 12:46: Hawking radiation is related to this whole vacuum energy virtual particle thing. 11:30: And just quickly regarding the objections of vacuum diagrams to some of my statements in this whole quantum vacuum series-- doctor diagrams, vacuum. 12:46: Hawking radiation is related to this whole vacuum energy virtual particle thing. 11:30: And just quickly regarding the objections of vacuum diagrams to some of my statements in this whole quantum vacuum series-- doctor diagrams, vacuum.
	2017-11-08: Zero-Point Energy Demystified 00:00: ... PLAYING] The mysterious zero-point energy, the quantum vacuum, has been a misrepresented subject of science fiction and pseudoscience ... 00:14: Let's talk about what vacuum energy really can and really can't do. 00:32: ... prediction of quantum field theory, that there exists an energy of the vacuum resulting from the non-zero zero-point energies of the quantum field ... 00:53: ... our observations of the accelerating expansion of the universe suggest a vacuum energy density of only 10 to the power of minus 8 ergs per centimeter ... 01:05: ... we discussed in the episode on the vacuum catastrophe, this mismatch between the measured and theoretical values ... 01:35: ... source to manipulating it to generate warp fields or pushing against the vacuum energy in propulsionalist space ship ... 01:54: Today I want to debunk some of the nonsense surrounding the quantum vacuum. 02:02: If the vacuum has an energy density of 10 to the power of ridiculous ergs per centimeter cubed, where is it? 03:29: And this would be the case even with an extremely energetic quantum vacuum. 03:35: On its own, the vacuum is the same everywhere. 03:45: No such movement is possible for the vacuum, and so the vacuum contains no useful energy. 04:02: In order to access vacuum energy, we need to introduce a disequilibrium. 04:08: In fact, we need to reduce the vacuum energy in one region of space. 04:31: By cutting off certain frequency modes between the plates, you lower the vacuum energy in that region. 05:18: Well, if we define the average vacuum energy as 0, then the Casimir Effect produces negative energy. 05:26: Unfortunately, the vacuum energy between Casimir plates is very much positive in an absolute sense. 05:36: That means the vacuum energy between Casimir plates still produces positive spatial curvature, not the negative curvature required for warp drives. 05:46: ... popular use for the quantum vacuum is as a medium to push against for propulsion engine systems, like the ... 06:10: Virtual particles, and hence, the quantum vacuum, mediate all forces. 06:15: However, it's not possible to transfer momentum from a particle to the vacuum without getting another real particle out the other end. 06:23: That momentum must be given up by the vacuum to produce real particles again. 06:33: In the case of the EM drive, the proposal is that microwaves within the drive's resonant cavity push against the quantum vacuum. 06:59: Vacuum energy is real, and it's part of the fundamental clockwork of the universe. 07:20: That said, the quantum vacuum does have its uses. 07:56: Geckos literally manipulate quantum vacuum energy to climb walls. 08:21: How many geckos do you need to catch and put on a leash in order to drag you up any wall, using only the power of the quantum vacuum? 08:35: ... as we saw last week, the theoretical density of the vacuum energy due to the electromagnetic field is estimated by integrating the ... 08:48: You get that the vacuum energy density is proportional to the fourth power of that cutoff frequency. 08:55: Based on the vacuum energy density, as we've already talked about, answer me this. 01:05: ... we discussed in the episode on the vacuum catastrophe, this mismatch between the measured and theoretical values of vacuum ... 00:14: Let's talk about what vacuum energy really can and really can't do. 00:53: ... our observations of the accelerating expansion of the universe suggest a vacuum energy density of only 10 to the power of minus 8 ergs per centimeter ... 01:05: ... this mismatch between the measured and theoretical values of vacuum energy is one of the greatest unsolved problems in ... 01:35: ... source to manipulating it to generate warp fields or pushing against the vacuum energy in propulsionalist space ship ... 04:02: In order to access vacuum energy, we need to introduce a disequilibrium. 04:08: In fact, we need to reduce the vacuum energy in one region of space. 04:31: By cutting off certain frequency modes between the plates, you lower the vacuum energy in that region. 05:18: Well, if we define the average vacuum energy as 0, then the Casimir Effect produces negative energy. 05:26: Unfortunately, the vacuum energy between Casimir plates is very much positive in an absolute sense. 05:36: That means the vacuum energy between Casimir plates still produces positive spatial curvature, not the negative curvature required for warp drives. 06:59: Vacuum energy is real, and it's part of the fundamental clockwork of the universe. 07:56: Geckos literally manipulate quantum vacuum energy to climb walls. 08:35: ... as we saw last week, the theoretical density of the vacuum energy due to the electromagnetic field is estimated by integrating the energy ... 08:48: You get that the vacuum energy density is proportional to the fourth power of that cutoff frequency. 08:55: Based on the vacuum energy density, as we've already talked about, answer me this. 00:53: ... our observations of the accelerating expansion of the universe suggest a vacuum energy density of only 10 to the power of minus 8 ergs per centimeter ... 08:48: You get that the vacuum energy density is proportional to the fourth power of that cutoff frequency. 08:55: Based on the vacuum energy density, as we've already talked about, answer me this. 06:10: Virtual particles, and hence, the quantum vacuum, mediate all forces.
	2017-11-02: The Vacuum Catastrophe 00:15: There's a massive disagreement between the theoretical and the measured values of the energy of the vacuum. 00:21: We call this theoretical fail the vacuum catastrophe. 00:32: The quantum vacuum is a seething ocean of activity. 01:13: Quantum field theory predicts that the energy of the vacuum should be up to 120 orders of magnitude greater than the measured value. 01:26: Let's talk about vacuum energy from a theoretical standpoint. 01:45: However, even the lowest possible energy oscillation, the one corresponding to the absence of particles, the so-called vacuum state, has some energy. 01:55: ... satisfy the Heisenberg uncertainty principle, the vacuum state of any fuel oscillation must be half of the tiny Planck constant ... 02:09: ... a minuscule amount of energy, except to properly describe a perfect vacuum, every single possible frequency mode at every point in space must have ... 02:23: To calculate the density of energy of the vacuum, we should add this tiny energy over an infinite range of frequency modes for all fields. 02:42: We'll get back to whether the idea of an infinite vacuum energy is actually possible. 03:31: ... if we add up the vacuum energy, including virtual photons, all the way up to the Planck energy, ... 03:49: ... enough energy to boil all of the oceans on the planet, yet even if vacuum energy did have a value this high-- in fact, even if it were infinite-- ... 04:23: As long as the vacuum energy is the same everywhere, then it's inaccessible to us as an energy source. 04:39: Long story short-- a crazily high, even infinite, vacuum energy doesn't affect the predictions of quantum field theory. 05:07: Vacuum energy should produce a gravitational effect, and a huge vacuum energy should produce a huge gravitational effect. 05:37: ... down that rabbit hole if you haven't already, but the upshot is that, if vacuum energy really did have the enormous value predicted by theory, then our ... 05:53: ... days of quantum field theory was the beginning of what would become the vacuum catastrophe, but it wasn't a full blown catastrophe ... 06:25: It gives particles a supersymmetric counterpart that may precisely cancel out their vacuum energy. 06:32: ... down to the so-called electroweak energy, which brings the predicted vacuum energy down to a mere 10 to the 47 ergs per centimeter ... 06:52: For a while, theorists assumed that something like this must be happening, meaning the vacuum energy was really 0. 07:09: ... is, in fact, accelerating in exactly the way we'd expect from a non-zero vacuum ... 07:20: ... of accelerating expansion allows us to measure the absolute density of vacuum ... 07:31: Assuming vacuum energy is to blame, dark energy weighs in at 10 to the power of negative 8 ergs per centimeter cubed. 07:59: ... can give us an extremely high vacuum energy or a vacuum energy of exactly 0 if we assume symmetry of positive ... 08:50: That would imply countless other universes with different, less comfortable vacuum energies. 11:05: Vacuum energy can't be used as a power source. 11:08: It's not just science fiction that abuses the vacuum this way. 00:21: We call this theoretical fail the vacuum catastrophe. 05:53: ... days of quantum field theory was the beginning of what would become the vacuum catastrophe, but it wasn't a full blown catastrophe ... 08:50: That would imply countless other universes with different, less comfortable vacuum energies. 01:26: Let's talk about vacuum energy from a theoretical standpoint. 02:42: We'll get back to whether the idea of an infinite vacuum energy is actually possible. 03:31: ... if we add up the vacuum energy, including virtual photons, all the way up to the Planck energy, we get a ... 03:49: ... enough energy to boil all of the oceans on the planet, yet even if vacuum energy did have a value this high-- in fact, even if it were infinite-- we may ... 04:23: As long as the vacuum energy is the same everywhere, then it's inaccessible to us as an energy source. 04:39: Long story short-- a crazily high, even infinite, vacuum energy doesn't affect the predictions of quantum field theory. 05:07: Vacuum energy should produce a gravitational effect, and a huge vacuum energy should produce a huge gravitational effect. 05:37: ... down that rabbit hole if you haven't already, but the upshot is that, if vacuum energy really did have the enormous value predicted by theory, then our gently ... 06:25: It gives particles a supersymmetric counterpart that may precisely cancel out their vacuum energy. 06:32: ... down to the so-called electroweak energy, which brings the predicted vacuum energy down to a mere 10 to the 47 ergs per centimeter ... 06:52: For a while, theorists assumed that something like this must be happening, meaning the vacuum energy was really 0. 07:09: ... is, in fact, accelerating in exactly the way we'd expect from a non-zero vacuum energy. ... 07:20: ... of accelerating expansion allows us to measure the absolute density of vacuum energy. ... 07:31: Assuming vacuum energy is to blame, dark energy weighs in at 10 to the power of negative 8 ergs per centimeter cubed. 07:59: ... can give us an extremely high vacuum energy or a vacuum energy of exactly 0 if we assume symmetry of positive and ... 11:05: Vacuum energy can't be used as a power source. 04:39: Long story short-- a crazily high, even infinite, vacuum energy doesn't affect the predictions of quantum field theory. 03:31: ... if we add up the vacuum energy, including virtual photons, all the way up to the Planck energy, we get a finite ... 01:45: However, even the lowest possible energy oscillation, the one corresponding to the absence of particles, the so-called vacuum state, has some energy. 01:55: ... satisfy the Heisenberg uncertainty principle, the vacuum state of any fuel oscillation must be half of the tiny Planck constant times ...
	2017-10-25: The Missing Mass Mystery 02:19: This energy of the vacuum comprises 70% of the universe's energy content. 07:48: That makes it a more perfect vacuum than anything we've created in a lab or even exists in the Milky Way. 11:21: A non-zero vacuum energy would have a gravitational effect. 11:34: So enough vacuum energy could result in a closed, rather than infinite, universe. 11:39: And rather differently to regular matter, vacuum energy doesn't dilute in an expanding universe. 12:09: The energy is borrowed from the energy of the vacuum for the minuscule time allowed by the uncertainty principle. 02:19: This energy of the vacuum comprises 70% of the universe's energy content. 11:21: A non-zero vacuum energy would have a gravitational effect. 11:34: So enough vacuum energy could result in a closed, rather than infinite, universe. 11:39: And rather differently to regular matter, vacuum energy doesn't dilute in an expanding universe.
	2017-10-19: The Nature of Nothing 03:21: We call this the vacuum state of the field. 03:25: Inside a perfect vacuum, all of the field at all locations should be in the vacuum state, exactly zero energy at all times. 04:07: In a vacuum, the most likely state in that blur is the zero energy vacuum state. 06:23: ... are just a mathematical tool to describe the behavior of a dynamic vacuum and that no such particles actually exist, or that they are only the ... 07:40: ... physicist Hans Bethe successfully explained it in terms of a fluctuating vacuum ... 08:15: Another way to hunt for virtual particles is through their bulk effect on the vacuum. 08:34: It should have vacuum energy. 08:51: ... any non-resonant virtual photon would be excluded, reducing the vacuum energy between the ... 09:11: The higher vacuum energy outside, compared to the inside of the plates, should result in a pressure differential that pushes the plates together. 09:42: Now while there are potentially other explanations for the observed force, this has been taken as strong evidence that vacuum energy is real. 09:51: Neither the Casimir effect nor the Lamb shift allow measurement of the absolute strength of vacuum energy. 10:05: So how much vacuum energy is there? 10:18: Dark energy itself may be vacuum energy. 10:22: ... so, then the amount of vacuum energy needed to produce the observed acceleration is tiny, around one ... 10:33: And the theoretical calculation of the strength of the vacuum energy is a little higher than that. 10:53: ... field theory, with its dependence on virtual particles and vacuum fluctuations, is one of the most successful theories in all of science, ... 07:40: ... physicist Hans Bethe successfully explained it in terms of a fluctuating vacuum energy. ... 08:34: It should have vacuum energy. 08:51: ... any non-resonant virtual photon would be excluded, reducing the vacuum energy between the ... 09:11: The higher vacuum energy outside, compared to the inside of the plates, should result in a pressure differential that pushes the plates together. 09:42: Now while there are potentially other explanations for the observed force, this has been taken as strong evidence that vacuum energy is real. 09:51: Neither the Casimir effect nor the Lamb shift allow measurement of the absolute strength of vacuum energy. 10:05: So how much vacuum energy is there? 10:18: Dark energy itself may be vacuum energy. 10:22: ... so, then the amount of vacuum energy needed to produce the observed acceleration is tiny, around one one ... 10:33: And the theoretical calculation of the strength of the vacuum energy is a little higher than that. 10:53: ... in all of science, and yet it's prediction of the strength of the vacuum energy seems to be wildly ... 10:22: ... so, then the amount of vacuum energy needed to produce the observed acceleration is tiny, around one one hundred ... 10:53: ... field theory, with its dependence on virtual particles and vacuum fluctuations, is one of the most successful theories in all of science, and yet it's ... 03:21: We call this the vacuum state of the field. 03:25: Inside a perfect vacuum, all of the field at all locations should be in the vacuum state, exactly zero energy at all times. 04:07: In a vacuum, the most likely state in that blur is the zero energy vacuum state.
	2017-10-11: Absolute Cold 01:17: Understanding the limit to cold will lead us to an understanding of the nature of the quantum vacuum itself. 06:21: For example, the quantum fields that fill our universe also fluctuate due to the Uncertainty Principle resulting in what we know as vacuum energy.
	2017-09-28: Are the Fundamental Constants Changing? 02:03: Its value today is 299,792,458 meters per second in a vacuum.
	2017-08-16: Extraterrestrial Superstorms 13:13: Vacuum Diagrams points out that two diagrams are missing from the challenge answer.
	2017-07-19: The Real Star Wars 05:31: But in the vacuum of space, these lasers can have ranges of many hundreds, even thousands of kilometers.
	2017-06-28: The First Quantum Field Theory 09:40: ... fields in the so-called hyperfine splitting or spins interacting with vacuum energy fluctuations in the lamb ... 13:33: ... Vacuum Diagrams points out that Schrodinger himself did write down a ... 14:26: ... when we're still struggling to reconcile it with general relativity?" Vacuum Diagrams had a great response that explains the problem of infinities ... 13:33: ... Vacuum Diagrams points out that Schrodinger himself did write down a relativistic ... 14:26: ... when we're still struggling to reconcile it with general relativity?" Vacuum Diagrams had a great response that explains the problem of infinities that both ... 13:33: ... Vacuum Diagrams points out that Schrodinger himself did write down a relativistic version of ... 09:40: ... fields in the so-called hyperfine splitting or spins interacting with vacuum energy fluctuations in the lamb ...
	2017-06-21: Anti-Matter and Quantum Relativity 13:50: Galdo145 asks whether bubble universes with different vacuum energies would convert to the lower energy state after colliding? 14:02: ... vacuum field can have one or more local minima, where the vacuum energy can ... 14:14: The vacuum energy may come to a rest at different minima in different bubbles or it can be a false vacuum in one and the true vacuum in the other. 14:23: If two bubbles with different vacuum energies collide, then the one with the higher energy should convert to the lower energy. 14:38: ... the high energy bubble, it's much worse because that change in the vacuum energy state would propagate at the speed of light to fill that ... 13:50: Galdo145 asks whether bubble universes with different vacuum energies would convert to the lower energy state after colliding? 14:23: If two bubbles with different vacuum energies collide, then the one with the higher energy should convert to the lower energy. 14:02: ... vacuum field can have one or more local minima, where the vacuum energy can come to a rest in an eternally inflating spacetime, halting ... 14:14: The vacuum energy may come to a rest at different minima in different bubbles or it can be a false vacuum in one and the true vacuum in the other. 14:38: ... the high energy bubble, it's much worse because that change in the vacuum energy state would propagate at the speed of light to fill that universe, ... 14:02: ... vacuum field can have one or more local minima, where the vacuum energy can come to a ...
	2017-06-07: Supervoids vs Colliding Universes! 09:13: In particular, its vacuum energy takes on a stable value.
	2017-04-19: The Oh My God Particle 03:09: All cosmic rays are traveling at pretty close to the speed of light, but that's the speed of light in a vacuum.
	2017-01-19: The Phantom Singularity 12:53: ... Club by looking at Harold White et al's paper on an apparently positive vacuum test of the EM ... 15:55: A vacuum test out of TU Dresden in Germany observed a thrust, but found the thrust was the same even if they stood the EM drive vertically. 17:09: But honestly, orbital tests don't eliminate most of the issues of vacuum chamber ground tests. 12:53: ... Club by looking at Harold White et al's paper on an apparently positive vacuum test of the EM ... 15:55: A vacuum test out of TU Dresden in Germany observed a thrust, but found the thrust was the same even if they stood the EM drive vertically.
	2017-01-11: The EM Drive: Fact or Fantasy? 00:08: They flooded in since Eagle Works Labs published a paper detailing their tests of an EmDrive in a hard vacuum chamber. 01:23: ... "Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum." First, a bit of ... 03:55: But the latest test was in a vacuum chamber at 1/10 billionth of sea level atmospheric pressure, so no convection is possible. 07:02: The paper invokes pilot wave theory as a way to justify treating the quantum vacuum as a sort of plasma with which it can exchange momentum. 07:19: Our understanding of the quantum vacuum in standard quantum field theory doesn't allow you to push off it, like you might row a boat on a lake. 07:59: Instead, they invoke pilot wave theory to justify treating the quantum vacuum as a deformable medium. 08:18: ... the quantum vacuum is some sort of almost classical medium, then they argue that the ... 08:29: ... of this is relevant unless the founding assumption is right, that the vacuum is something very different than described by the otherwise amazingly ... 09:01: A distant third is that it's something brand new, like this quantum vacuum stuff. 00:08: They flooded in since Eagle Works Labs published a paper detailing their tests of an EmDrive in a hard vacuum chamber. 03:55: But the latest test was in a vacuum chamber at 1/10 billionth of sea level atmospheric pressure, so no convection is possible. 09:01: A distant third is that it's something brand new, like this quantum vacuum stuff.
	2016-12-08: What Happens at the Event Horizon? 16:16: Vacuum Diagrams correctly points out that to know the future trajectory of a particle, you only need position, not velocity, as I had stated. 16:47: ... and some of it was from people who know a good deal more than I do, like Vacuum ... 16:16: Vacuum Diagrams correctly points out that to know the future trajectory of a particle, you only need position, not velocity, as I had stated. 16:47: ... and some of it was from people who know a good deal more than I do, like Vacuum Diagrams. ... 16:16: Vacuum Diagrams correctly points out that to know the future trajectory of a particle, you only need position, not velocity, as I had stated.
	2016-05-18: Anti-gravity and the True Nature of Dark Energy 02:03: A constant cosmological constant represents a nonzero energy of empty space, a vacuum energy. 02:18: OK, the big, weird fact about a constant vacuum energy density is that leads to exponential expansion. 13:09: ... mechanical tabulators followed by solid state relay calculators, then vacuum tube ... 02:03: A constant cosmological constant represents a nonzero energy of empty space, a vacuum energy. 02:18: OK, the big, weird fact about a constant vacuum energy density is that leads to exponential expansion. 13:09: ... mechanical tabulators followed by solid state relay calculators, then vacuum tube ...
	2016-05-11: The Cosmic Conspiracy of Dark Energy Challenge Question 02:25: If that constant truly stays constant over time, then it represents an energy of the vacuum.
	2016-04-27: What Does Dark Energy Really Do? 07:36: This lets us interpret the cosmological constant as representing a sort of vacuum energy, a property of space itself. 07:48: But why should a constant vacuum energy cause the universe to accelerate? 07:36: This lets us interpret the cosmological constant as representing a sort of vacuum energy, a property of space itself. 07:48: But why should a constant vacuum energy cause the universe to accelerate?
	2016-04-20: Why the Universe Needs Dark Energy 07:54: We call it "dark energy," and we interpret it as an energy possessed by empty space itself-- by the vacuum. 08:04: ... density of regular matter will, at some point, drop below that of this vacuum energy, as described by the cosmological-constant ...
	2016-03-23: How Cosmic Inflation Flattened the Universe 08:05: And we'll explore exactly what could cause such a weird sort of energetic vacuum real soon-- inflatons, scalar fields, forced vacuums, all of that. 08:15: ... fact that empty space can propel its own expansion and will do so if the vacuum contains a ubiquitous constant energy ... 08:05: And we'll explore exactly what could cause such a weird sort of energetic vacuum real soon-- inflatons, scalar fields, forced vacuums, all of that.
	2016-02-03: Will Mars or Venus Kill You First? 01:57: So we're talking close to a vacuum here. 03:21: ... pretty soon after exposure to a vacuum, your blood will be leached of oxygen, starving your brain, and at some ... 03:49: In 1966, a NASA vacuum chamber space suit test went horribly wrong, leaving Jim LeBlanc exposed to a vacuum. 04:09: ... fact, it's understood that you can survive exposure to a complete vacuum for around 90 seconds, as long as someone drags you back into that ... 03:49: In 1966, a NASA vacuum chamber space suit test went horribly wrong, leaving Jim LeBlanc exposed to a vacuum.
	2015-12-16: The Higgs Mechanism Explained 01:28: But even in a vacuum, the electron field is there.
	2015-10-28: Is The Alcubierre Warp Drive Possible? 06:02: Quantum scale manipulation of the vacuum energy a la the Casimir effect may be enough.
	2015-10-22: Have Gravitational Waves Been Discovered?!? 05:11: Split it in two, and then send the twin beams at right angles down four-kilometer long vacuum tubes.
	2015-10-07: The Speed of Light is NOT About Light 00:14: ... from traveling at any speed but 300,000 kilometers per second in a vacuum-- according to any observer-- and, two, keep anything from traveling ...
	2015-08-19: Do Events Inside Black Holes Happen? 06:15: They're not vacuum cleaners.
	2015-06-10: What Happens to a Helium Balloon in Freefall? 00:56: So for simplicity, let's just say that the van is falling through a vacuum.
	2015-04-08: Could You Fart Your Way to the Moon? 00:20: ... a suit with a special valve that would allow you to pass gas into the vacuum of ... 02:33: But in the near total vacuum of space, expelling gas would have to make you move.

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