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PBS Space Time
Season 2021 • Episode 31 • Is ACTION The Most Fundamental Property in Physics?
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PBS Space Time Season 2021, Episode 31: Is ACTION The Most Fundamental Property in Physics?
It’s about time we discussed an obscure concept in physics that may be more fundamental than energy and entropy and perhaps time itself. That’s right - the time has come for Action. Watch PBS Space Time Season 2021, Episode 31 Is ACTION The Most Fundamental Property in Physics? in HD free online. Enjoy high-quality streaming of PBS Space Time Season 2021, Episode 31 and share your thoughts in the comments below!
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Episodes
35 episodesWhat Happens During a Quantum Jump?
Since the very beginning of quantum mechanics, a debate has raged about how to interpret its bizarre predictions. And at the heart and origin of that debate is the quantum jump or quantum leap - the seemingly miraculous and instantaneous transitions of quantum systems that have always defied observation or prediction. At least, until now.
13 min
Can We Break the Universe?
Today we’re going to delve into a couple of the most famous paradoxes of special relativity: the Twin Paradox, The Ladder Paradox (aka the Barn-Pole Paradox), and a paradox suggested by our very own viewers, which asks whether a spaceship could wrap around the universe & destroy itself. We’ll explore these paradoxes and see why, against our intuition, the universe really does work in this seemingly nonsensical way. But the point of this episode is to go much further - we’re going to try to break the universe by pushing these paradoxes beyond the limit.
17 min
Is Dark Matter Made of Particles?
Dark Matter Particles: Gateway to The Dark Universe
17 min
How Does Gravity Warp the Flow of Time?
There’s a deep connection between gravity and time - gravitational fields seem to slow the pace of time in what we call gravitational time dilation. And today we’ll explore the origin of this effect. And ultimately, we’ll use what we learn to understand how curvature in time - this gradient of time dilation - can be thought of as the true source of the force of gravity.
13 min
Gravitational Wave Background Discovered?
It was pretty impressive when LIGO detected gravitational waves from colliding black holes. Well we’ve just taken that to the next level with a galaxy-spanning gravitational wave detector that may have detected a foundational element of space itself - the gravitational wave background.
19 min
Does Time Cause Gravity?
We know that gravity must cause clocks to run slow on the basis of logical consistency. And we know that gravity DOES cause clocks to run slow based on many brilliant experiments. But I never explained WHY or HOW gravity causes the flow of time to slow down. And I’m not going to explain it now - because in a sense it’s not true. Gravity does NOT warp the flow of time. It’s the other way around - the warping of time causes gravity.
12 min
How Does Gravity Affect Light?
We know that gravity exerts its pull on light, and we have an explanation for why. Actually, we have multiple explanations that all predict the same thing. And at first glance, these explanations seem to describe completely different causes. So what is the true connection between light and gravity, or is truth, in fact, entirely relative?
14 min
The NEW Crisis in Cosmology
I have good news and bad news. Bad news first: two years ago we reported on the Crisis in Cosmology. Since then, it’s only gotten worse. And actually, the good news is also that the crisis in cosmology has actually gotten worse, which means we may be onto something! The most exciting thing for any scientist is when something they thought they knew turns out to be wrong. So it’s no wonder that many cosmologists are starting to get excited by what has become known as the Hubble tension, or the crisis in cosmology. The “crisis” is the fact that we have two extremely careful, increasingly precise measurements of how fast the universe is expanding which should agree with each other, and yet they don’t.
19 min
Zeno's Paradox & The Quantum Zeno Effect
“A moving arrow is at rest.” This is obviously a nonsensical contradiction. But Zeno, a Greek philosopher famous for his metaphysical trolling, devised a paradox whose conclusion is just this. Here’s how it goes: if you look at an arrow flying through the air at any instantaneous snapshot in time, the arrow doesn’t travel any distance. If time is composed of an infinite number of these snapshots, and the arrow doesn’t move in any of them, then the arrow is at rest during the entirety of its flight. The moving arrow is at rest.
18 min
Why the Muon g-2 Results Are So Exciting!
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13 min
What If Dark Matter Is Just Black Holes?
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13 min
The NEW Warp Drive Possibilities
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19 min
How To Know If It's Aliens
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20 min
Breaking The Heisenberg Uncertainty Principle
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12 min
What If (Tiny) Black Holes Are Everywhere?
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17 min
Are We Running Out of Space Above Earth?
While recent news about the Chinese Long March 5 Rocket made a lot of people very nervous because a 22-ton rocket was going to fall out of the sky, this sort of thing happens all the time. Boosters, dead satellites, and sometimes even old space stations get dropped out of the sky fairly often. While the litter seems a little inconsiderate, this is probably far safer than the alternative. The accumulation of space junk poses a huge risk to all human operations in space especially if we cross the threshold into the chain reaction of exponentially growing collisions known as the Kessler Syndrome.
17 min
Can Space Be Infinitely Divided?
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13 min
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20 min
Electrons DO NOT Spin
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19 min
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14 min
How Magnetism Shapes The Universe
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20 min
How An Extreme New Star Could Change All Cosmology
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19 min
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20 min
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14 min
First Detection of Light from Behind a Black Hole
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18 min
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15 min
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20 min
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19 min
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18 min
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17 min
Is ACTION The Most Fundamental Property in Physics?
It’s about time we discussed an obscure concept in physics that may be more fundamental than energy and entropy and perhaps time itself. That’s right - the time has come for Action.
20 min
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19 min
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17 min
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21 min
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15 min