
20220817: What If Dark Energy is a New Quantum Field?
 01:41: ... that the antigravitational effect of dark energy is due to it having negative pressure. That’s counterintuitive because negative pressure is an inward pulling ...
 02:31: ... dark energy is that, on top of the antigravitational effect of its negative pressure, it also produces regular attractive gravity due to its positive energy ...
 12:31: ... omega is between ⅓ and 1 then the outwardpushing negative pressure still dominates over the inward pull of regular gravity, so expansion ...


20220420: Does the Universe Create Itself?
 15:24: ... because it’s a positive energy density, just like matter. But it’s negative pressure can allow even a closed universe to expand forever. Thanks, dark ...


20201027: How The Penrose Singularity Theorem Predicts The End of Space Time
 05:01: ... always produce this convergence. It would take negative mass or negative pressure to cause light rays to diverge. This focusing property of ...


20200630: Dissolving an Event Horizon
 04:10: ... the central singularity  which pointlike in this case  results in a negative pressure that again resists the inward pull of ...


20200527: Does Gravity Require Extra Dimensions?
 11:58: This is the negative pressure due to the exclusion of quantum vacuum modes, or virtual particles, between two very closely separated plates.


20200518: Mapping the Multiverse
 13:13: ... black holes the electromagnetic field within causes massive tension, or negative pressure that produces an antigravitational ...


20190109: Are Dark Matter And Dark Energy The Same?
 02:53: But here’s the punchline: if empty space has a constant, positive energy density then it also has a negative pressure.
 03:02: For obscure reasons that we delve into those episodes, negative pressure produces an antigravitational effect.
 03:10: ... positive energy density gives it a positive gravitational effect but its negative pressure is ...
 07:57: And that a positive Lambda results in an antigravitational negative pressure?


20180620: The Black Hole Information Paradox
 13:20: ... electric charge within the black hole produces a negative pressure that actually halts the cascade of space within the black hole and ...


20170405: Telescopes on the Moon
 11:33: ... singularity is expected to produce an antigravitational effect through negative pressure, in a way that's mathematically similar to dark ...


20160525: Is an Ice Age Coming?
 12:01: Last week, we wrapped up our conversation on dark energy, talking about antigravity, negative pressure, and conservation of energy.


20160518: Antigravity and the True Nature of Dark Energy
 08:24: It's negative pressure.
 08:26: What does negative pressure even mean?
 08:33: So negative pressure would pull inwards.
 08:49: Negative pressure pulls in.
 09:05: The direct effect of dark energy's negative pressure doesn't do anything, because that negative pressure is the same everywhere in the universe.
 09:14: But even though the negative pressure has no direct effect, it has its relativistic effect.
 09:19: Relativistically, negative pressure has to do the opposite of positive pressure and results in antigravity, because math.
 09:29: The relativistic effective of negative pressure is actually really, really hard to describe intuitively.
 09:38: Part of the problem is that negative pressure doesn't come from the motion of dark energy particles, whatever they might be.
 10:09: That's exactly how we define negative pressure.
 10:12: A volume has negative pressure if it takes work to expand, just like a volume with positive pressure takes work to compress.
 10:22: Negative pressure means energy is gained on expansion.
 10:35: That looks like negative pressure, and yet this abstractsounding negative pressure has a very real physical effect.
 11:01: But both agree that a constant energy density and the resulting negative pressure leads to accelerating expansion.


20151028: Is The Alcubierre Warp Drive Possible?
 03:44: We can create something like it, a negative pressure, on quantum scales via Casimir effect.
