Search PBS Space Time


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

  • 06:05: ... distance  of Pluto, or well over 500 times the Earth’s   orbital radius. Around 550 “astronomical  units” or “AUs” in ...
  • 09:31: ... spacecraft starts out by launching  backwards compared to Earth’s orbital direction,   using sails to slow down and sort of tack ...

2022-09-28: Why Is 1/137 One of the Greatest Unsolved Problems In Physics?

  • 02:36: ... spins are separated slightly by their interaction with their own orbital magnetic ...
  • 04:17: And the orbital speed of an electron in the ground state of the Bohr model of the hydrogen atom is 137 slower than the speed of light.

2022-08-24: What Makes The Strong Force Strong?

  • 00:28: ... electrons are held in their orbitals by the electromagnetic force - opposite charges attract, so the ...
  • 03:38: Well, slight correction: electron orbitals can contain two electrons, but that’s because those electrons can have a different spin state.
  • 06:20: So an electron bound to an atomic nucleus will feel less force from the nucleus at larger orbitals.

2022-06-22: Is Interstellar Travel Impossible?

  • 08:26: ... onto our ship by the ISM is around a billion times lower compared to orbital ...

2022-05-25: The Evolution of the Modern Milky Way Galaxy

  • 05:58: ... same merger, they should also have similar  orbits. If their orbital speeds are even   slightly different, they may have ...
  • 06:57: ... also found a group of 13 globular clusters   with matching orbital properties and spectra  that were probably once part of ...

2022-03-08: Is the Proxima System Our Best Hope For Another Earth?

  • 06:18: Such a short orbital period, combined with the star’s mass, gave them an orbital radius for the exoplanet of around 20 times smaller than the Earth’s.
  • 09:17: ... have forced the planet’s rotation period to be in resonance with its orbital ...
  • 10:26: Other orbital resonances can occur - for example, 2 days per year, 3 days per 2 years, etc.

2021-11-10: What If Our Understanding of Gravity Is Wrong?

  • 02:18: That means the orbital velocities of stars out there should be lower in order to keep them in orbit.
  • 02:25: The so-called rotation curve should drop - orbital  speed should diminish with distance from center.

2021-08-03: How An Extreme New Star Could Change All Cosmology

  • 03:19: ... it gives us spectral lines. When electrons in an atom move between orbitals, they emit or absorb light with very specific wavelengths. That tells us ...
  • 09:18: ... together because they emit gravitational radiation that saps away their orbital energy. We’ve seen the result of this with black holes and neutron stars ...

2021-07-21: How Magnetism Shapes The Universe

  • 05:11: Although it’s less of a sphere and more of a teardrop - dragged into that shape by the Sun’s orbital motion through the galaxy.

2021-07-07: Electrons DO NOT Spin

  • 02:25: ... magnetic field like a tiny bar magnet. The different alignments of that orbital magnetic field relative to the external field turns one energy level ...
  • 03:20: ... it acts like a tiny bar magnet. So you have the alignment of both the orbital magnetic moment and the electron’s  internal moment contributing ...

2021-06-23: How Quantum Entanglement Creates Entropy

  • 13:44: ... later. But that was 40 years ago,   and the number of tracked orbital debris has increased from around 4500 to more like ...
  • 15:02: ... presumably our future AI overlords will be better at managing our orbital space,   which will further reduce the Kessler ...

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

  • 01:45: ... while a loose screw or paint chip may not be all that scary on earth, at orbital speeds of 7 km/s they can carry as much energy as a ...
  • 05:53: This is another positive feedback loop - orbital decay accelerates until the satellite finally burns in a glorious blaze of re-entry.
  • 06:18: That’s annoying, but orbital decay is the most important process for cleaning low-earth orbit of defunct satellites and debris.
  • 06:26: Ultimately, the Kessler Syndrome can be avoided if orbital decay cleans up low-earth orbit faster than new launches and new collisions fill it.
  • 08:33: So bringing this all together we can paint a picture of our trashed orbital space.
  • 13:14: ... to maintain our cosmic front yard, and continue our safe use of Earth’s orbital space ...

2021-02-10: How Does Gravity Warp the Flow of Time?

  • 10:17: ... note of caution: be aware that circular orbital motion in a gravitational field is very different from our rotating ...

2020-09-21: Could Life Evolve Inside Stars?

  • 14:19: ... any arbitrarily complex orbital motion can be represented with enough sine wave pairs in a fourier ...

2020-07-08: Does Antimatter Explain Why There's Something Rather Than Nothing?

  • 09:19: ... measure the difference in energies between the various positron orbitals in the anti-atoms using laser spectroscopy. The exact energy of one of ...
  • 12:37: ... keep working on the cake, but in the meantime have a wonderful next orbital revolution - from me and all the space time ...

2020-06-30: Dissolving an Event Horizon

  • 07:20: It’s that orbital angular momentum that is fed to the black hole.

2020-06-15: What Happens After the Universe Ends?

  • 14:49: ... patreon supporters will have their names encoded in the orbital frequencies of colliding suppermassive black holes at the end of time to ...

2020-01-27: Hacking the Nature of Reality

  • 00:14: The year is 1925 and the young Werner Heisenberg is striving to understand the mechanics of the newly-discovered electron orbitals of hydrogen.
  • 00:43: ... the mysterious frequencies of light produced as electrons jump between orbitals. ...
  • 14:29: ... some places it gives up angular momentum - it's orbital energy - to the gas, causing it to migrate inwards, while in other ...

2020-01-20: Solving the Three Body Problem

  • 11:21: ... were likely - and by doing so they could map the range of likely orbital properties for the two objects left behind after the ejection. This ...
  • 12:21: ... series that added together an endless chain of terms to solve the orbital calculation. Because the series converged, which successive terms ...

2020-01-13: How To Capture Black Holes

  • 00:59: ... of space into expanding ripples - gravitational waves - which saps orbital energy from the system. The black holes spiral closer and closer ...
  • 05:58: ... hole pair gets captured by the disk, the surrounding gas saps their orbital energy much more quickly than by gravitational radiation alone. This ...

2019-10-07: 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.

2019-09-23: Is Pluto a Planet?

  • 05:37: ... Orbital calculations put the object beyond the orbit of Neptune, and it appeared ...
  • 06:07: It also seemed too faint to possibly have the mass required to explain Uranus’s orbital discrepancies.

2019-06-06: The Alchemy of Neutron Star Collisions

  • 02:47: ... slowly spiral towards each other as a gravitational radiation saps their orbital energy in the last minute before merger that radiation is so strong that ...

2019-05-16: The Cosmic Dark Ages

  • 08:11: ... or emitted when an electron jumps between the ground and second electron orbitals of ...

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

  • 16:55: ... plane - MUCH bigger than the SpaceShipTwo launcher and designed for orbital rocket launches as well as space ...

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

  • 06:32: ... a few minutes in space the craft re-enters and lands. It never reaches orbital velocity so it's low speed reentry is less fraught than say the space ...

2018-12-06: Did Life on Earth Come from Space?

  • 00:37: ... ahead to get to the nearest stars a rock traveling at the sun's galactic orbital speed of 30 km/s would take several tens of thousands of years but real ...

2018-08-01: How Close To The Sun Can Humanity Get?

  • 07:17: Venus will end up traveling infinitesimally faster as it absorbs Parker's orbital energy.
  • 07:38: ... its orbital period will be the same as Mercury's-- 88 days-- because of its ...
  • 07:54: ... spin roughly, 11 days doing science during each orbital cycle, while spending the other 77 days in the outer parts of its ...

2018-03-28: The Andromeda-Milky Way Collision

  • 06:20: When those black holes are around a light year apart, they'll start losing orbital energy to gravitational waves.

2018-03-07: Should Space be Privatized?

  • 02:09: To spur private competition, NASA implemented its Commercial Orbital Transport Services Program in 2011.
  • 02:32: Orbital ATK followed closely.

2018-01-31: Kronos: Devourer Of Worlds

  • 03:34: That means they're almost certainly a wide binary pair with an orbital period of around 10,000 years.

2017-12-20: Extinction by Gamma-Ray Burst

  • 08:16: Also, further observations with the Keck telescopes indicate that the system's orbital axis isn't pointed directly at the Earth.
  • 08:30: But the orbital axis of a binary system and the rotational axis of its stars are often correlated, so we may have dodged a bullet in this case.

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

  • 00:51: ... after 34 days of follow up observations, and a bit of orbital mechanics, it became abundantly clear that we were looking at the first ...

2017-10-19: The Nature of Nothing

  • 02:41: In each quantum state, so each combination of particle properties, there is a ladder of energy levels, a bit like electron orbitals in an atom.
  • 07:10: ... Rutherford noticed a tiny energy difference between the two electron orbitals that comprise the second energy level of the hydrogen ...
  • 07:26: According to the best existing theory of the time, those orbitals should have had exactly the same energy.
  • 07:50: Virtual particle-antiparticle pairs in the space between the orbitals and the nucleus align themselves with the electric field.

2017-10-11: Absolute Cold

  • 02:07: They can only occupy certain energy levels of vibration or motion, much like the discrete electron orbitals in an atom.

2017-10-04: 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.

2017-09-28: Are the Fundamental Constants Changing?

  • 04:34: Electron energy levels-- or orbitals in atoms-- are quantized, meaning only certain levels are allowed.
  • 05:38: ... magnetic fields produced by an electron's spin and by its orbital motion actually interact with each other in an effect called spin orbit ...
  • 05:48: There are two stable configurations for this interaction-- the little bar magnet may be aligned with the orbital field, or opposite to it.
  • 06:02: So when electrons jump between orbitals, the energy they absorb or emit depends on their spin alignment.
  • 13:10: It would send a spacecraft to at least 550 times the Earth's orbital radius, out beyond the edge of the solar system.

2017-09-13: Neutron Stars Collide in New LIGO Signal?

  • 03:30: The rate of loss of orbital energy exactly matches the expected rate of emission of gravitational radiation.

2017-07-19: The Real Star Wars

  • 02:01: Despite definitely being in space, these are called suborbital trajectories because they don't actually reach orbital velocity.
  • 02:33: ... Soviet program, the Fractional Orbital Bombardment System, actually did enter true orbit, and it would allow ...

2017-06-21: Anti-Matter and Quantum Relativity

  • 03:24: In the case of electrons in atoms, it suggests that we should only find one electron per atomic orbital, if we count each orbital as a quantum state.
  • 03:34: However, we actually observe two electrons per orbital.

2017-05-17: Martian Evolution

  • 03:36: We know that the zero-G experienced in orbital or interplanetary space leads to decreased bone density and muscle mass in astronauts.

2017-04-05: Telescopes on the Moon

  • 12:39: The sideways components, angular or orbital components in spherical coordinates, stay space-like.

2017-03-29: How Time Becomes Space Inside a Black Hole

  • 03:06: This equation assumes no orbital motion, only motion towards or away from the center of the black hole, which is a distance r away.

2017-03-15: Time Crystals!

  • 10:52: Well, that's where orbital resonance comes in.
  • 10:55: The planet's orbital periods have evolved so that each pair of planets lines up at regular intervals.

2017-03-01: The Treasures of Trappist-1

  • 02:13: ... planets have now settled into stable orbital resonances with each other, and that's a hint that they may have formed ...

2017-02-22: The Eye of Sauron Reveals a Forming Solar System!

  • 06:13: Fomalhaut B shows up as a bright orbital body in Hubble images.

2017-01-19: The Phantom Singularity

  • 17:09: But honestly, orbital tests don't eliminate most of the issues of vacuum chamber ground tests.

2016-12-14: Escape The Kugelblitz Challenge

  • 05:55: Plan A is to build an infinitely-strong Dyson sphere surrounding the earth just outside the moon's orbital radius.

2016-08-24: Should We Build a Dyson Sphere?

  • 04:33: We start with limited mining, space launch, and orbital construction facilities, all of it autonomous.

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

  • 12:35: My pleasure-- a resonant frequency is when two orbiting bodies have orbital periods that form a neat ratio of small integers.

2016-07-06: Juno to Reveal Jupiter's Violent Past

  • 03:50: Jupiter probably didn't form in its current orbital location.
  • 05:37: Saturn would have quickly followed until it fell into orbital resonance with Jupiter, three of Saturn's orbits to every two of Jupiter's.

2016-05-25: Is an Ice Age Coming?

  • 08:37: There is an unfortunate combination of orbital properties that kickstarts this process.

2016-04-06: We Are Star Stuff

  • 09:27: ... those remnants will eventually spiral in as they radiate away their orbital energy in gravitational ...

2016-03-16: Why is the Earth Round and the Milky Way Flat?

  • 10:05: Disks happen when orbital motion dominates the resistance to gravity.

2016-02-11: LIGO's First Detection of Gravitational Waves!

  • 02:30: But gravitational waves carry energy, which is sapped from the orbital energy of the system.
  • 02:40: Now we've seen this slow orbital decay in binary neutron stars.

2015-11-25: 100 Years of Relativity + Challenge Winners!

  • 02:28: First, let's do the calculation in the frame of reference of Apophis' 2029 orbital velocity.
  • 02:45: The x-axis is the orbital path of the asteroid.

2015-08-27: Watch THIS! (New Host + Challenge Winners)

  • 01:09: ... from what I just said, you can also work out an expression for the orbital period of a particle moving under the planet's gravity in a circular ...

2015-08-12: Challenge: Which Particle Wins This Race?

  • 00:59: ... Newtonian gravity, you can work out an expression for the orbital speed of this particle in terms of the mass and radius of the planet, or ...

2015-06-24: The Calendar, Australia & White Christmas

  • 04:27: The orbital plane wobbles.
  • 04:33: Now, one effect of all this orbital craziness is that the mean tropical year is actually getting shorter by about a half second every 100 years.
  • 06:58: ... a few tens though, going in different orbital planes, you could actually probably see them from most places, because ...

2015-05-27: Habitable Exoplanets Debunked!

  • 01:04: ... the habitable zone, in turn, is defined as the sweet spot of orbital distances from that star at which the energy from starlight would ...
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