
20221026: Why Did Quantum Entanglement Win the Nobel Prize in Physics?
 06:51: Spin is the quantum version of angular momentum.
 06:54: ... the atom’s spin hadn’t changed in this transition, in order to conserve angular momentum the pair of photons needed to have a total spin of zero, which ...


20220630: Could We Decode Alien Physics?
 07:38: ... are everywhere in physics, for example in calculating torque, angular momentum, and through Maxwell’s equations. The right hand rule is another ...


20220316: What If Charge is NOT Fundamental?
 02:23: For example electrons have this thing called spin  a quantum analogy to angular momentum.


20211117: Are Black Holes Actually Fuzzballs?
 01:14: ... can observe from outside a black hole are its mass, electric charge, and angular momentum. ...


20211110: What If Our Understanding of Gravity Is Wrong?
 06:06: It doesn’t respect conservation of energy or momentum or angular momentum.


20210810: How to Communicate Across the Quantum Multiverse
 14:02: ... here  first is that a white dwarf could potentially gain a lot of angular momentum or spin by absorbing material from another star, hence perhaps ...


20210803: How An Extreme New Star Could Change All Cosmology
 02:13: ... collapses under its own gravitational crush due to conservation of angular momentum. But typical white dwarfs take from a few hours to a few days to rotate. ...
 09:51: ... would be spinning really really fast because it doesn’t just have the angular momentum from its spinning parent stars  it has the angular momentum from the ...


20210721: How Magnetism Shapes The Universe
 09:53: Magnetic fields generated by collapsing gas clouds help to slow the rotation of those clouds  expel angular momentum.


20210707: Electrons DO NOT Spin
 00:22: ... rotate on the chair. It’s a demonstration of the conservation of angular momentum. The angular momentum of the wheel is changed in one direction, so ...
 00:47: ... constant speed. At first glance this appears to violate conservation of angular momentum because there was nothing spinning to start with. Except there was ...
 01:26: ... wheels. And yet they do seem to possess a very strange type of angular momentum that somehow exists without classical rotation. In fact the spin of an ...
 03:48: ... surfaces would have to be moving faster than light to give the required angular momentum. And that’s assuming that electrons even have a size  as far as we know ...
 04:40: ... so electrons aren’t spinning, but somehow they act like they have angular momentum. And this is how we think about quantum spin now. It’s an intrinsic ...
 10:22: To get some insight into what spin really is, think not about angular momentum, but regular or linear momentum.
 10:58: If position is the companion variable of momentum, what's the companion of angular momentum?
 11:09: ... one way to think about the angular momentum of an electron is not from classical rotation, but rather ...
 11:21: They have undefined orientation, but perfectly defined angular momentum.
 11:34: ... that you can derive the right values of the electron spin angular momentum and magnetic moment by looking at the energy and charge currents ...
 11:44: ... imply that even if the electron is point like, it's angular momentum can arise from an extended though still tiny ...


20210623: How Quantum Entanglement Creates Entropy
 16:39: ... is no preferred angle. That’s the basis for the conservation of angular momentum, which we know is obeyed. Another issue with the simple ...


20210407: Why the Muon g2 Results Are So Exciting!
 03:43: For a rotating charge, that depends on the objects rate of rotation, or angular momentum, it's charge and it's mass.


20200708: Does Antimatter Explain Why There's Something Rather Than Nothing?
 09:19: ... factors: the precise mass and charge of the particles, their orbital angular momentum, their magnetic and electric dipole moments, and even the strength of the ...


20200630: Dissolving an Event Horizon
 04:57: In both cases, the amount of angular momentum or charge you can fit into a black hole before it becomes extremal depends on the mass.
 06:06: This can’t happen with rotating black holes because they leak away their angular momentum as well as their mass.
 07:11: Rotating black holes gain their angular momentum from things they swallow.
 07:20: It’s that orbital angular momentum that is fed to the black hole.
 07:24: But in order for an object orbiting a black hole to fall into it, it actually has to lose at least some of that angular momentum.
 07:31: ... black hole like in a quasar, then the gas only spirals inwards because angular momentum is carried outwards by ...
 07:42: By the time the gas reaches the black hole it has lost much of the angular momentum it started with.
 07:49: The faster a black hole is rotating, the more angular momentum that gas has to lose in order to fall in.
 07:55: ... a sort of boost so it can still orbit even with very little of its own angular momentum. ...
 08:06: ... entirely riding on the carousel of framedragged state, and has no angular momentum of its ...
 08:30: More generally, there is no trajectory into an extremal black hole that can add angular momentum from the trajectory or the “orbit” itself.
 08:43: An alternative is to throw in something that’s actually spinning itself  so it has intrinsic angular momentum.


20200622: Building Black Holes in a Lab
 07:24: ... in a vortex black hole analog. In fact, both the analog of energy and angular momentum seems to be sapped by this Hawkinglike ...


20200428: Space Time Livestream: Ask Matt Anything
 00:00: ... because they grow in mass when they swallow things they conserve angular momentum and charge because they acquire those properties when they swallow ...


20200324: How Black Holes Spin Space Time
 01:44: ... holes will be rotating. The spin of a black hole comes from the combined angular momentum of everything that went into forming it. That includes the rotation of ...
 02:26: ... black holes might not have MUCH spin  because angular momentum can cancel out if objects fall in with different spins or in different ...


20200316: How Do Quantum States Manifest In The Classical World?
 04:28: ... have to be in opposite directions in order to cancel out and conserve angular momentum. But besides being opposite to each other they can be aligned in any ...


20200127: Hacking the Nature of Reality
 14:29: ... some places it gives up angular momentum  it's orbital energy  to the gas, causing it to migrate inwards, while ...
 14:41: And between these inward and outward migration regions are places where no angular momentum is exchanged. And, well, the black hole is trapped.


20200120: Solving the Three Body Problem
 10:30: ... configurations consistent with some basic properties like the energy and angular momentum of the system. The system explores what we call a phase space  a space ...


20200113: How To Capture Black Holes
 06:15: ... properties of the disk, that can cause the object to either gain or lose angular momentum. If it gains angular momentum the size of its orbit increases, so it ...


20191015: Loop Quantum Gravity Explained
 08:20: ... called a spinor  a vectorlike thing that also represents a quantum of angular momentum  or ...


20191007: Black Hole Harmonics
 09:05: .69 means this is a rapidly rotating black hole, which is unsurprising seeing as it just absorbed the orbital angular momentum of two black holes.


20190124: The Crisis in Cosmology
 15:31: ...both linear and angular momentum.


20190116: Our Antimatter, Mirrored, TimeReversed Universe
 03:02: ... point in the opposite direction to regular matter relative to their angular momentum the magnetic field in our clock will align antimatter nuclei in the ...


20181212: Quantum Physics in a Mirror Universe
 00:02: ... the energy of the ball its mass the time on its clock and as we'll see angular momentum don't change in the mirror universe now even though some signs do get ...


20180920: Quantum Gravity and the Hardest Problem in Physics
 14:25: As they lose spin, angular momentum, they become more spherical.


20180815: Quantum Theory's Most Incredible Prediction
 04:02: Nonetheless, electrons do have a sort of intrinsic, angular momentum, a fundamental quantum spin that is as intrinsic as mass and charge.
 05:09: ... value you'd expect for a tiny classical sphere with the same charge and angular momentum as an ...


20180620: The Black Hole Information Paradox
 01:54: It states that black holes can only exhibit three properties mass, electric charge, and angular momentum.


20180613: What Survives Inside A Black Hole?
 01:09: ... properties are mass, electric charge, and angular momentum, or at least this is the proposition behind the famous nohair conjecture ...
 01:45: ... he proposed that no other properties besides mass, electric charge, and angular momentum should emerge from beneath the event ...
 02:28: ... into the black hole are its massenergy content, electric charge, and angular momentum. ...
 03:06: So how does mass, electric charge, and angular momentum communicate their influence across the uncrossable horizon?
 08:30: But what about the magnetic part of electromagnetism, and what about angular momentum?
 09:19: ... material with angular momentum falls into a black hole, whether it's a spinning star or a whirlpool of ...
 09:30: Its angular momentum is remembered in the frame dragging as though the entire black hole was spinning.
 09:36: I hope I've given you a sense of why mass, charge, and angular momentum are remembered by the space outside a black hole.


20180516: Noether's Theorem and The Symmetries of Reality
 04:07: ... the earth then, Noether's theorem predicts another conserved quantity, angular momentum. ...


20180328: The AndromedaMilky Way Collision
 06:16: Meanwhile, the black holes lose angular momentum and fall towards the center.


20180131: Kronos: Devourer Of Worlds
 09:05: It tugs on the Earth gravitationally, increasing our angular momentum.
 09:10: The asteroid loses angular momentum in the process, but it regains it as it flies by Jupiter.
 09:15: Essentially, we steal angular momentum from Jupiter via the asteroid, which increases our orbit.


20171011: Absolute Cold
 08:38: ... of years for this black hole binary to spiral together from losing angular momentum to gravitational ...
 09:03: So they probably lose angular momentum by dragging against gas in the center of galaxies, but we don't know how long that takes.


20171004: When Quasars Collide STJC
 07:35: Each time they do that they lose a bit of orbital energy or angular momentum, causing them to fall deeper into the gravitational well.
 08:52: ... waves, but it's going to take many billions of years to lose enough angular momentum to merge that ...


20170621: AntiMatter and Quantum Relativity
 02:42: But spin does result in a sort of quantum angular momentum.
 04:05: ... the up and down degrees of freedom were the direction of pointing of the angular momentum ...


20170222: The Eye of Sauron Reveals a Forming Solar System!
 02:51: Conservation of angular momentum has the central star spinning rapidly.


20160824: Should We Build a Dyson Sphere?
 07:22: ... radiation, from heat generated from infalling material, or by extracting angular momentum from the black hole's ...


20160706: Juno to Reveal Jupiter's Violent Past
 04:12: A planet can lose angular momentum to the debris, causing its orbit to shrink.
 04:25: The planet can even migrate outwards, stealing angular momentum from the debris.
 05:27: Drag from that gas would have sapped angular momentum from Jupiter, causing it to migrate inwards until it stalled at around 1.5 AU.


20160323: How Cosmic Inflation Flattened the Universe
 12:52: ... like the rate of accretion, the viscosity of the material, the way angular momentum is lost by that material, stuff like ...


20160316: Why is the Earth Round and the Milky Way Flat?
 10:26: They also give us things like the Laws of Conservation of Energy and of Linear and Angular Momentum, topics that we will get to.


20150506: Should the First Mars Mission Be All Women?
 09:14: Fortstorm asks, wouldn't a rotating stations have trouble turning because its angular momentum vector would have trouble being shifted?
 09:22: ... so that there would be gravity here and gravity here but no net angular momentum, and thus no net gyroscope ...


20150325: Cosmic Microwave Background Explained
 05:50: ... trick was to cancel out all the intermediate angular momentum vectors produced as a flywheel with forwardpointing angular momentum ...
 06:00: ... the solution is to have two flywheels, both with forwardpointing angular momentum that you rotate into the reverse orientation in opposite ...
 06:08: That way, any sideways intermediate angular momentum that gets produced is canceled out.
 06:43: ... material could be spun sufficiently fast, you could store up a lot of angular momentum with very little ...


20150318: Can A Starfox Barrel Roll Work In Space?
 02:03: That tendency to keep rotating is called an objects' angular momentum, and physicists represent it by a vector or an arrow.
 02:23: To do that, the shipments needs to acquire a forwardpointing angular momentum vector.
 02:27: To stop, that angular momentum must be removed.
 02:59: But what if you could store up the angular momentum in advance and carry it with you?
 03:04: And I don't mean having the ship doing a nonstop barrel roll, I mean happy angular momentum on demand without thrusters.
 03:23: By rotating the flywheel quickly, I end up transferring its angular momentum to myself, so I start spinning.
 03:47: So its angular momentum vector points toward the nose of the ship, which here is the top of your screen.
 03:53: ... can also think of this vector as the net angular momentum of the entire ship flywheel system, all of which currently happens to ...
 04:04: When I flip the flywheel 180 degrees, its individual angular momentum starts pointing toward the rear of the ship, i.e.
 04:12: But the net angular momentum of the entire ship wheel system must remain unchanged.
 04:17: That can happen only if the entire fuselage acquires its own large, forwardpointing angular momentum.
 04:23: That, combined with the wheel's angular momentum, nets out to the same total angular momentum vector we began with.
 04:56: Space telescopes, like Hubble and Kepler, also use angular momentum conservation to turn without thrusters.
 05:33: ... or how fast they'd have to spin in the first place to store up enough angular momentum for the barrel ...
 05:50: ... low, then unlike with thrusters, you can keep storing and reusing that angular momentum to do as many barrel rolls as you ...
 06:18: In the process, both of flipping and of flipping back, its angular momentum vector sweeps through a bunch of partiallysideways directions.
 06:25: To compensate, the ship would have to do some wonky rotating as the flywheel flips, in order to keep the total angular momentum vector unchanged.
