Search PBS Space Time


2022-10-12: The REAL Possibility of Mapping Alien Planets!

  • 09:31: ... that intense up-close solar radiation. That propels the craft on a trajectory   that will take them out of the solar system and towards our first ...

2022-08-03: What Happens Inside a Proton?

  • 08:58: ... diagram   you’re actually adding infinite possible  trajectories using Feynman path ...

2022-03-30: Could The Universe Be Inside A Black Hole?

  • 04:07: That trace will define the path of the thrown ball, but you can also extrapolate beyond the ball’s trajectory.

2022-01-27: How Does Gravity Escape A Black Hole?

  • 14:55: We said that the room-sized computer used to calculate the Apollo trajectories had the computing power of a smart phone.

2022-01-19: How To Build The Universe in a Computer

  • 02:56: ... Isaac Newton it had been possible to write down equations describing the trajectories of a pair of massive bodies moving in each other’s gravitational ...
  • 04:17: And I would hope so, because this is essentially  how we calculate the trajectories that place people on the moon or land robots on comets.

2021-11-02: Is ACTION The Most Fundamental Property in Physics?

  • 00:02: ... of least time?. If light changes speed between media, then the fastest trajectory is no longer a straight line. With this principle of least time, Fermat ...
  • 01:22: ... if there was a similar property that could be minimized to determine the trajectories of matter as well as light? There were some efforts - for example Euler ...
  • 08:39: ... between its source and the screen not as a particle with a well-defined trajectory, but as a quantum wavefunction that represents all possible paths it ...
  • 09:24: ... action says that a particle will always land where the action of the trajectory is at a minimum or maximum. That should correspond only to the central ...
  • 12:16: ... all of this together. Configuration space is the space of all possible trajectories given our object’s constraints. In the case of the ball, configuration ...

2021-10-05: Why Magnetic Monopoles SHOULD Exist

  • 07:02: To plot that trajectory you add up all possible paths of the electron, including paths to the left and to the right at the string.

2021-09-07: First Detection of Light from Behind a Black Hole

  • 08:47: ... emerging picture is that gas falls in along some trajectories, but then gets lifted off the accretion disk by the blazing radiation of ...

2021-06-09: Are We Running Out of Space Above Earth?

  • 03:59: And their future trajectories can be calculated to predict possible future collisions.

2021-03-23: Zeno's Paradox & The Quantum Zeno Effect

  • 02:58: ... position; its wavefunction is spread between the start and end of the trajectory. ...
  • 04:41: ... observation resets the trajectory to the start, at which point the wavefunction has to start evolving from ...

2021-03-16: The NEW Crisis in Cosmology

  • 16:28: ... For those who don't know, the path integral calculates the trajectory of a quantum object   by adding up all possible and even ...

2021-01-12: What Happens During a Quantum Jump?

  • 09:47: And that transition appeared to be perfectly described by theory - in this case quantum trajectory theory.
  • 10:19: ... that the quantum jump onset was predictable, and that its trajectory was extremely well described by theoretical calculations, it’s tempting ...

2020-12-15: The Supernova At The End of Time

  • 13:37: ... to "remember" the future collision you have to know the present trajectories of these two far-apart ...

2020-11-18: The Arrow of Time and How to Reverse It

  • 06:57: ... typically, on very small scales due to random alignments of particle trajectories or however else energy is moving around. Entropy can decrease, reach a ...

2020-06-30: Dissolving an Event Horizon

  • 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.

2020-05-18: Mapping the Multiverse

  • 08:13: There are trajectories in this torus that lead you back to your starting location - in both space AND time.

2020-03-31: What’s On The Other Side Of A Black Hole?

  • 01:53: ... in both these regions, the Schwarzschild metric canNOT be used to plot a trajectory that actually crosses the event horizon. That’s because at the event ...
  • 03:46: ... Kruskal–Szekeres coordinates improved our map by enforcing that the trajectory of light always be at a 45 degree angle. In the resulting ...

2020-03-24: How Black Holes Spin Space Time

  • 05:14: ... We see it around any rotating mass. In frame dragging, any “freefall” trajectory - the path taken by an object moving freely in the gravitational field - ...
  • 09:06: ... is dropped into the ergosphere of a kerr black hole on a carefully tuned trajectory. ...

2020-03-16: How Do Quantum States Manifest In The Classical World?

  • 16:29: ... produce a new big bang? Could a random perfect alignment of all particle trajectories produce a big bang density? Maybe - some physicsts think this may be how ...
  • 17:40: ... equal. You can imagine the wavefunction as consisting of very many fine trajectories - possible histories by which the system can evolve. Some final results ...

2020-02-24: How Decoherence Splits The Quantum Multiverse

  • 04:22: We can think of those paths as slices of the wavefunction that represent possible trajectories.
  • 04:28: The probability of the photon having reached this particular spot is determined by the sum of all possible trajectories to that spot.

2020-01-20: Solving the Three Body Problem

  • 05:25: ... them one at a time. A sufficiently small section of any gravitational trajectory can be approximated with an exact, analytical solution - perhaps a ...

2019-03-20: Is Dark Energy Getting Stronger?

  • 16:12: They followed suborbital trajectories, which left them in space for only minutes.

2019-03-13: Will You Travel to Space?

  • 08:09: ... Richard means when he says point-to-point travel. These space-kissing trajectories could one day allow us to travel halfway across the globe in a couple of ...
  • 12:08: ... made its first successful trip to space, and not on a sub-orbital trajectory. ...

2019-01-30: Perpetual Motion From Negative Mass?

  • 06:48: A so-called geodesic path is the trajectory of an object in a gravitational field assuming no additional forces.
  • 07:31: In the analogy a positive mass depresses the sheet so that the trajectory of an positive mass apple bends towards the massive object.
  • 07:40: But those trajectories only depend on the active gravitational mass of the central object, and on the velocity and starting position of the apple.
  • 08:08: Trajectories curve away from the source, and that looks like a repulsive force.

2018-12-12: Quantum Physics in a Mirror Universe

  • 00:02: ... unaltered in that mirror world Newton's laws will still give the balls trajectory those laws work the same no matter the direction of motion in fact if we ...

2018-11-21: 'Oumuamua Is Not Aliens

  • 00:44: But what made this object special was its trajectory.
  • 09:22: ... socked from its orbit by impact and or gravitational interaction into a trajectory that will send it to the ...

2018-11-14: Supersymmetric Particle Found?

  • 07:02: ... coming in at an angle, skimming the arc of the earth on a shallow trajectory. ...

2018-10-31: Are Virtual Particles A New Layer of Reality?

  • 07:46: And that uncertain momentum gives them real locations, real trajectories through space.

2018-09-20: Quantum Gravity and the Hardest Problem in Physics

  • 14:03: It's possible to extract energy from a rotating black hole by throwing in objects on near-miss trajectories.

2018-07-25: Reversing Entropy with Maxwell's Demon

  • 05:41: The demon has the ability to observe speed and trajectories of individual particles in the system.
  • 07:08: Weirdly, it's not in the measurement of particle trajectories or the motion of the door.

2018-05-16: Noether's Theorem and The Symmetries of Reality

  • 12:10: ... fitting laws of motion to the stars' five-year trajectory, there's only a very narrow trajectory of extremely precise locations ...

2018-04-04: The Unruh Effect

  • 04:03: ... can never catch up to my friend as long as they stay on that hyperbolic trajectory. ...

2018-03-15: Hawking Radiation

  • 04:58: He imagined a single spacetime path, a lightspeed trajectory called a null geodesic.
  • 05:14: In fact, it is the very last trajectory to do so.
  • 05:37: By the time this trajectory has found its way back out into flat space again, those fluctuations look like real particles.

2018-03-07: Should Space be Privatized?

  • 03:14: ... Mike Melvill, blasted this rocket-powered plane into a suborbital trajectory, topping 100 kilometers in ...

2018-02-28: The Trebuchet Challenge

  • 06:19: This time, you release the projectile a little earlier, so it takes a more vertical trajectory.

2017-12-13: The Origin of 'Oumuamua, Our First Interstellar Visitor

  • 08:53: Its trajectory we'll send it towards the constellation Pegasus, perhaps to find a new star system there to visit.

2017-11-22: Suicide Space Robots

  • 08:33: Pioneer 10 and 11, Voyager 1 and 2, and New Horizons are all on trajectories that will fling them into interstellar space.

2017-07-19: The Real Star Wars

  • 00:43: It seemed to many that we were on a trajectory to a spacefaring technological utopia.
  • 01:51: ... orbit satellites, hitting around 1,200 kilometers at the peak of their trajectories. ...
  • 02:01: Despite definitely being in space, these are called suborbital trajectories because they don't actually reach orbital velocity.

2017-07-07: Feynman's Infinite Quantum Paths

  • 04:58: In relativity, it's proportional to the proper time, so the time measured by the clock on a given trajectory.
  • 10:54: However, unlike the ridiculous infinite trajectories a particle can take, those infinite events don't cancel out nearly so neatly.

2017-04-19: The Oh My God Particle

  • 04:02: ... analyzing the energies and trajectories of the debris, the collision that produced them and the nature of the ...

2017-03-22: Superluminal Time Travel + Time Warp Challenge Answer

  • 09:08: If we assume that this trajectory is valid, then there's no limit to how far into the past we can travel.
  • 10:29: Even our fantasies of time travel are just another pattern emerging from our one-way trajectory through the temporal part of spacetime.

2017-03-08: The Race to a Habitable Exoplanet - Time Warp Challenge

  • 00:18: In fact any FTL ship set on the right trajectory can find its way back in time to a point before its journey began.
  • 04:21: ... a spacetime trajectory that allows you to fly the Paradox all the way back to the beginning of ...

2016-12-08: What Happens at the Event Horizon?

  • 03:32: As it approaches the event horizon, its future light cone bends towards the black hole as fewer and fewer of its possible trajectories lead away.
  • 03:42: Below the event horizon, all possible trajectories lead towards the singularity.
  • 04:39: Super handy for understanding monkey trajectories.
  • 14:50: ... asks how it can be that pilot wave theory predicts different particle trajectories, given that the particles supposedly all start at exactly the same ...
  • 15:42: This uncertainty leads to the range of potential future trajectories, including trajectories through one slit or the other.
  • 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.

2016-11-30: Pilot Wave Theory and Quantum Realism

  • 04:45: The wave defines a set of possible trajectories and the particle takes one of those trajectories.
  • 04:51: ... and velocity at any point, you could figure out its entire future trajectory. ...
  • 09:30: This can therefore affect the trajectories and properties of particles carried by that wave, potentially very far away.
  • 11:05: Quantum field theory pretty explicitly requires that all possible particle trajectories be considered equally real.
  • 11:13: Pilot-wave theory postulates that the particle really takes a single actual trajectory, the Bohm trajectory.

2016-10-26: The Many Worlds of the Quantum Multiverse

  • 01:24: Quantum mechanics very successfully predicts this result by describing each particle's journey as a superposition of all possible trajectories.
  • 06:20: ... Copenhagen interpretation tells us that the superposition of particle trajectories, of histories, merges into the single timeline of the observer's ...

2016-07-27: The Quantum Experiment that Broke Reality

  • 07:02: ... have this family of could-be trajectories from start to finish and for some reason, when the wave reaches the ...

2015-07-29: General Relativity & Curved Spacetime Explained!

  • 07:50: ... what you find is planetary orbits or spatially straight, radially inward trajectories along which you would see spatial speed increase, or pretty much ...

2015-07-15: Can You Trust Your Eyes in Spacetime?

  • 07:16: ... time, like what you might see in a physics 101 class, tangent vectors to trajectories represent velocities, how fast you're going and in what ...

2015-07-08: Curvature Demonstrated + Comments

  • 02:31: Suppose that he breaks up the trajectory from here to here into 1,000 steps and does that process.
  • 06:10: ... they converge at the North Pole, even though neither person on those trajectories ...
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