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2022-09-21: Science of the James Webb Telescope Explained!

  • 04:03: The very first galaxies shone with intense ultraviolet light as the dense, young gas of the early universe collapsed into the first stars.

2022-06-22: Is Interstellar Travel Impossible?

  • 08:02: Interstellar space is quite a bit less dense than the upper atmosphere - by a factor of around 10^16.

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

  • 02:19: ... thing   is sprinkled with wayward stars and ancient,  dense mini-galaxies called globular clusters.   But mostly the halo ...

2022-05-04: Space DOES NOT Expand Everywhere

  • 08:34: ... apart objects and the spacetime grids they trace. But in sufficiently dense regions gravity won and there the only evidence of the greater expansion ...

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

  • 08:53: They get denser towards the center and have plenty of pressure.

2022-01-12: How To Simulate The Universe With DFT

  • 00:18: That’s how insanely information dense the quantum wavefunction really is.

2021-12-20: What Happens If A Black Hole Hits Earth?

  • 01:49: ... There would have been some regions that just happened to be especially dense. Countless black holes might have formed at the earliest of times, while ...

2021-11-17: Are Black Holes Actually Fuzzballs?

  • 08:55: In fact, if you have a bunch of strings dense enough to form a black hole in general relativity, it wouldn’t actually collapse.

2021-09-21: How Electron Spin Makes Matter Possible

  • 17:29: ... own particle, moving around the lattice. But this pseudoparticle is less dense that its surroundings, so it eventually rises to the surface and so gets ...

2021-09-15: Neutron Stars: The Most Extreme Objects in the Universe

  • 02:35: ... out  very tenuous - almost a vacuum,   and then gets denser as we drop.  But the similarities end there.   Earth’s ...
  • 09:34: ... form sheets. That’s right - nuclear lasagna.  And because it’s so dense, it’s really  hard to bend and move this stuff. Nuclear ...

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

  • 03:48: They sputter and flare with violent events, for example as dense clumps of gas hitting the center, or magnetic instabilities shaking things up.

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

  • 12:16: ... may get its explosive finale after all. A typical white dwarf is pretty dense, at around a metric ton per cubic ...
  • 12:50: ... is a 1000 times denser still. That means it can support incredibly energetic electrons in its ...

2021-07-21: How Magnetism Shapes The Universe

  • 08:30: These are the densest regions of those galactic disks - places where magnetic fields have confined the charged particles of the interstellar plasma.

2021-07-07: Electrons DO NOT Spin

  • 15:31: ... t=0, the universe was extremely compact - which meant hot and  dense, and it was also extremely smooth. The compact part is where the low ...

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

  • 09:18: But these lowest orbits are the most useful and cheapest to launch to - and so are the most densely populated.
  • 15:32: ... asked whether a region dense in Planck relics would emit high-energy radiation as the relics merged ...

2021-04-13: What If Dark Matter Is Just Black Holes?

  • 06:53: ... white dwarf, but it would deposit enough heat to allow the stars' ultra dense carbon and oxygen to undergo nuclear ...
  • 07:14: They're so dense, that they would stop a microscopic black hole in its tracks.
  • 10:01: ... galaxies are so small and dense that even black holes with tens of solar masses should have trickled to ...

2021-03-16: The NEW Crisis in Cosmology

  • 10:08: ... of ancient sound waves   that reverberated through the hot, dense plasma of the early universe. Now those ripples are ...

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

  • 07:17: ... galaxies and the particles that comprise them back and calculate a much denser, more “special” arrangement - in fact an incredibly low entropy ...

2020-10-27: How The Penrose Singularity Theorem Predicts The End of Space Time

  • 01:17: ... after Einstein published them,   revealing that a sufficiently dense ball of matter would be surrounded by a surface where time ...
  • 01:58: ... enough to produce an event horizon - nor   even whether such dense matter would  really contract into a single point.   It ...
  • 09:31: ... that the universe is expanding, and probably started in a much denser state. In fact the latter   had been verified by the detection ...
  • 10:15: ... could, for example, miss and weave past each other in an insanely dense but not   infinitely dense knot. This might be the ...

2020-09-01: How Do We Know What Stars Are Made Of?

  • 04:22: Once it gets close to the surface, material is much less dense, so there are fewer free electrons to do the scattering.

2020-08-17: How Stars Destroy Each Other

  • 03:30: They result when denser streams of matter hit the white dwarf and flare due to heat, but do not produce the storm of fusion of the classical nova.
  • 06:03: ... binaries, that fluctuation includes powerful flares, resulting from denser clumps of material hitting the rapidly rotating surface of the neutron ...
  • 12:12: ... black holes may have formed from the extremely dense matter of the early universe, and these would have different mass ...

2020-06-30: Dissolving an Event Horizon

  • 01:12: Without it, the infinitely dense singularity and its surrounding madness is exposed to the outside universe.

2020-06-22: Building Black Holes in a Lab

  • 03:26: ... - right down to the emission of Hawking radiation. The details are a bit dense for YouTube, but I’ll link a lovely paper by Matt Visser for those who ...

2020-05-04: How We Know The Universe is Ancient

  • 03:24: ... no alternative - the universe must have once been in an extremely hot, dense state, and expanded from there. Astronomers call this the big bang model ...
  • 09:39: ... For a while we thought we’d found globular clusters - ancient, dense groups of stars - that were 15 billion years old. As bad as finding ...

2020-01-20: Solving the Three Body Problem

  • 11:21: ... This looks to be incredibly useful for understanding the evolution of dense regions of the universe, where three-body systems of stars or black ...

2020-01-13: How To Capture Black Holes

  • 00:59: ... may end their lives to leave a pair of binary black holes. And in very dense environments like the cores of galaxies, lone black holes may find each ...
  • 03:34: ... falling together. Now binary black hole pairs surely do exist in the dense galactic center, but they may have trouble merging in such a dense ...

2019-12-17: Do Black Holes Create New Universes?

  • 03:26: ... collapses, its mass doesn’t all end up stuck in the central, infinitely dense ...
  • 09:09: ... mostly produce neutron stars - planet sized balls of neutrons so dense that they teeter on the edge of collapsing into a black ...
  • 09:34: The resulting material is even denser than the original neutron star, and so brings the star closer to collapse.

2019-08-19: What Happened Before the Big Bang?

  • 00:04: That is as long as you define 'The Big Bang' as the universe's early hot dense expanding state that's well described by Einstein's equations.
  • 05:26: This gives us the expanding hot dense universe that we know and love in our Big Bang model.

2019-08-06: What Caused the Big Bang?

  • 10:59: ... evolve as the rest of the Big Bang story predicts: An extremely hot dense ocean of matter and radiation that slowly cools and disperses and forms ...

2019-07-18: Did Time Start at the Big Bang?

  • 01:22: ... Theory is just a theory" Let me be very clear, the evidence for a hot dense early universe is practically ...
  • 01:56: ... Whose ratio is exactly what we expect if the entire universe was a dense billions of degrees nuclear furnace for the first several minutes of its ...
  • 04:38: ... it enough times and the universe could end up as hot and dense as you like But it'll still be infinite, spatially, the scale factor is ...

2019-06-17: How Black Holes Kill Galaxies

  • 02:54: ... we look out into the Universe so galaxies first grew in clusters in the densest parts of the Universe Places where enormous worlds of Dark Matter pulled ...
  • 07:21: ... across the Universe slowly rose it became concentrated in the most denser region of the Universe where giant ellipticals assembled the rising ...

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

  • 13:02: ... 300 Kelvin. And Spluff5 asks us another related question, "how dense was the gas just after recombination?" - well let's figure it out the ...

2019-05-09: Why Quantum Computing Requires Quantum Cryptography

  • 15:35: But dark matter alone could never clump together densely enough to produce a black hole by itself.

2019-03-06: The Impossibility of Perpetual Motion Machines

  • 14:50: More dense regions were a little hotter, so recombination started later in those.

2019-02-20: Secrets of the Cosmic Microwave Background

  • 00:08: ... Background radiation The remnants of the heat glow released when the hot dense early Universe became transparent for the first time It sounds like ...

2019-01-24: The Crisis in Cosmology

  • 07:07: The Cosmic Microwave Background is the remnant heat glow of the universe's initial hot dense state.
  • 07:46: ...and also slightly more dense These over-densities...

2018-08-23: How Will the Universe End?

  • 04:15: It's so densely packed that all possible quantum states are completely filled and no further collapse is possible, short of becoming a black hole.
  • 08:38: ... annihilate themselves as they collide with each other or be captured by dense stellar remnants during the Degenerate Age and, ultimately, end up in ...
  • 10:11: Black dwarfs decay into iron stars-- still degenerate and insanely dense, but now perfect balls of iron.

2018-05-02: The Star at the End of Time

  • 09:24: Joshua Hillerup asks whether dynamical friction leads to less dark matter near the centers of galaxies since dark matter's not very dense.
  • 09:41: ... light years of the Milky Way stellar disk and the much smaller and denser stellar ...
  • 09:54: ... that the supermassive black hole in our galaxy center is in itself a dense swarm of smaller black holes in a shared orbit amounting to the same ...

2018-04-25: Black Hole Swarms

  • 00:24: The stars are so densely packed that the night sky would be 500 times brighter than our own.
  • 01:38: Well, the simple answer is straightforward-- dense things sink.
  • 01:43: Colder and hence denser water or air, sinks to the bottom of the ocean or the atmosphere.
  • 01:49: Dense elements, like iron, sink to the centers of forming planetary bodies in a process called differentiation.
  • 01:56: And the densest, stellar objects, like black holes, sink to the centers of galaxies or star clusters.
  • 03:50: They're like ancient, extremely dense mini-galaxies, containing millions of stars.
  • 08:05: ... black holes are so densely packed in the centers of galaxies, then we should probably know that, if ...

2018-04-18: Using Stars to See Gravitational Waves

  • 07:52: ... it may be possible to observe this effect in the dense star fields of galactic cores if those galaxies also contain binary ...

2018-04-11: The Physics of Life (ft. It's Okay to be Smart & PBS Eons!)

  • 00:56: A hot cup of coffee will tend towards the same temperature as the room, and the hot, dense of our universe must expand.
  • 01:24: ... the matter in the observable universe being crunched into an infinitely dense point are low ...

2018-01-24: The End of the Habitable Zone

  • 01:28: ... collapse from a giant gas cloud was halted as soon as the core became dense enough, dense enough for fusion to produce exactly the energy to balance ...

2017-11-08: Zero-Point Energy Demystified

  • 03:10: But try to drive your car in a dense 1,500 Kelvin atmosphere, and the piston has no reason to rise.

2017-10-25: The Missing Mass Mystery

  • 05:37: In the nexuses between filaments matter is dense enough for galaxies to form.
  • 06:15: We typically see that stuff inside galaxy clusters where the plasma is relatively dense and is energized by the light of the galaxies themselves.
  • 07:08: But it can't be so hot or dense as to emit detectable X-rays.
  • 10:35: As those baryons fall into the dense nexuses of the cosmic web, they'll feed galaxies with material to form new stars.

2017-10-04: When Quasars Collide STJC

  • 05:27: ... can splatter as their fuel supply changes or as the jets smash into denser regions of the surrounding ...
  • 06:21: ... the black hole where the jet begins, we think the matter should be so dense that the lowest energy radio waves have trouble escaping the ...

2017-09-20: The Future of Space Telescopes

  • 01:22: But these planets are extremely difficult to directly image because they are dense and small.

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

  • 01:54: When a massive star ends its life in a supernova explosion, it leaves behind an ultra dense core.

2017-08-16: Extraterrestrial Superstorms

  • 05:21: All of this happens in the troposphere, the densest and innermost layer of the atmosphere.

2017-08-02: Dark Flow

  • 01:44: The CMB is the leftover heat glow from the hot dense early universe.

2017-05-31: The Fate of the First Stars

  • 02:18: Today, they're found in the galactic bulge or in globular clusters, which are ancient, dense islands of stars that orbit far out in the galactic halo.

2017-04-26: Are You a Boltzmann Brain?

  • 01:04: For example, the hot, dense gas in a recently fired engine piston only expands because it's surrounded by a colder, less dense environment.
  • 01:18: But if you put the compressed piston in an environment that's full of equally hot, dense gas, nothing happens.
  • 04:26: ... will occasionally converge into a dense environment like a black hole or a galaxy, or into a complex arrangement ...

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

  • 03:23: But in that densely packed system, it covers three of the planets.

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

  • 02:14: Start with a dense core in a giant molecular cloud.
  • 02:38: The protostar continues to collapse more slowly until eventually the core gets hot and dense enough to ignite in fusion.

2017-02-02: The Geometry of Causality

  • 14:02: Well, although quasar accretion disks can reach some pretty crazy temperatures, they aren't particularly dense.

2017-01-19: The Phantom Singularity

  • 01:43: ... often use the word singularity to describe the hypothetically infinitely dense core of a black hole, but in math the meaning of this word is much more ...

2016-12-14: Escape The Kugelblitz Challenge

  • 03:51: OK, in the case of the collapsing start, that's still a core, is going to be an insanely hot, dense place and not great for observers.

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

  • 13:45: And the problem is that the universe at this time wasn't dense enough and was expanding too quickly for strange matter to form in any great abundance.
  • 15:45: Also, it's dense but not necessarily strong.

2016-11-16: Strange Stars

  • 02:49: ... quickly gives way to a fluid of almost pure neutrons, neutronium, the densest known substance in the ...
  • 04:50: In that state, it forms a superfluid rather than a plasma, a superfluid even denser than neutronium.

2016-10-19: The First Humans on Mars

  • 03:35: That means either living underground or building dense shelters from local material.
  • 08:56: ... possibility that primordial black holes formed in the insanely dense conditions right after the Big Bang and that these might still be around ...

2016-09-29: Life on Europa?

  • 06:11: That surface is by far the most densely populated region in the oceans beneath the Antarctic Sea ice.

2016-04-27: What Does Dark Energy Really Do?

  • 04:40: Now, that actually points to a more dense universe.

2016-04-20: Why the Universe Needs Dark Energy

  • 09:43: Within these regions, the shape of spacetime is dominated by the gravitational field of the densely packed matter.
  • 10:38: Even with dark matter, the universe is just not dense enough to recollapse.

2016-04-06: We Are Star Stuff

  • 03:28: ... about 20 minutes after the Big Bang, the entire universe was hot and dense enough for nuclear fusion, for protons to slam together hard enough to ...

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

  • 11:12: Felix Ironfist asks, "why didn't the universe collapse into a black hole, if it was so dense and massive?" This is a classic question.

2016-03-09: Cosmic Microwave Background Challenge

  • 00:15: It tells us that the universe was once most certainly much smaller, hotter, and denser than it is today.

2016-03-02: What’s Wrong With the Big Bang Theory?

  • 00:41: Direct and convincing evidence tells us that the universe was once much smaller, hotter, and denser than it is now.
  • 12:21: The Big Bang describes a series of events that happened to the universe following its existence in an extremely hot, dense state.

2016-02-24: Why the Big Bang Definitely Happened

  • 01:04: ... descriptions detailing the expansion of the universe from a tiny, super dense, super hot speck to the enormous cosmos that we know ...
  • 03:34: One such prediction is that the entire universe was once as hot and dense and opaque as the inside of a star.
  • 04:38: ... to explain without a universe that was once much smaller, hotter, and denser. ...

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

  • 02:25: These super dense objects produce serious gravitational radiation.

2015-12-09: How to Build a Black Hole

  • 02:09: The collapsing outer shells ricochet off this impossibly dense nugget in a supernova explosion, enriching the galaxy with juicy new elements.
  • 06:23: So a neutron star is comprised of the densest matter in the universe.
  • 06:55: And here's the thing-- the denser the neutron star becomes, the more momentum space you get.

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

  • 01:26: This is kind of a coincidence of the specific situation of a uniformly dense planet and Newtonian mechanics.
  • 01:46: You have to do the algebra in this case, because this is very specific to the situation of a uniformly dense planet.

2015-08-19: Do Events Inside Black Holes Happen?

  • 08:37: ... three, that all black holes are super dense-- this kind of depends on what you mean by "density." If you know that ...
  • 08:50: For instance, the 4 million solar mass black hole at the center of the Milky Way is about as dense as water.
  • 09:13: ... mean by "density." Maybe you mean that all black holes are infinitely dense because all the stuff that goes into the black hole collapses to an ...

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

  • 01:26: But I think it's easier to pretend that the planet is a uniformly dense fluid, and that this particle can pass through that fluid without friction.

2015-06-17: How to Signal Aliens

  • 09:51: Now, how do you reconcile this with the fact that helium is still less dense than air?
  • 10:02: ... get less dense as you rise in the opposite direction of a gravitational field, because ...

2015-06-03: Is Gravity An Illusion?

  • 04:26: ... that air is piling up in the rear of the car and getting slightly denser there, so the balloon is just trying to go toward the less dense air ...
  • 04:57: The pendulum hangs down and the balloon aims up because air is denser on the ground and less dense at higher altitudes.

2015-04-01: Is the Moon in Majora’s Mask a Black Hole?

  • 02:09: OK, so how dense is Termina's moon?
  • 04:00: ... Termina's moon really were only as dense as Earth's moon, its tidal force when hovering just above the planet's ...
  • 04:22: ... moon to be-- wait for it-- between a billion and 100 trillion times denser than Earth's moon, depending on whether you think the tidal force is ...
  • 04:57: The only solid macroscopic objects in nature that are that dense are neutron stars.
  • 05:03: Those objects could only get that dense in the first place because of their immense self-gravity.
  • 05:32: So if it's not a neutron star, how can Majora's moon be so dense?
  • 05:39: ... you could somehow put a much denser mass at the center, the material around it might have enough of a ...
  • 05:50: So to serve as a gravitational seed, we need something incredibly small and incredibly dense, even denser than a neutron star.

2015-03-18: Can A Starfox Barrel Roll Work In Space?

  • 05:33: ... I can't tell you how massive or dense the gyros would need to be, whether you'd flip them mechanics or with ...

2015-03-04: Should We Colonize Venus Instead of Mars?

  • 04:45: ... at that altitude, the atmosphere is still dense enough for lots of stuff to floae-- like balloons filled with helium or ...
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