PBS Space Time

Science and Nature Series / 11 Seasons

PBS Space Time explores the outer reaches of space, the craziness of astrophysics, the possibilities of sci-fi, and anything else you can think of beyond Planet Earth. Host Matt O'Dowd breaks down both the basic and incredibly complex sides of space and time.

5m 57s

Why Do You Remember The Past But Not The Future?

S7 E1 / 12m 7s

The laws of physics don’t specify an arrow of time - they don’t distinguish the past from the future. The equations we use to describe how things evolve forward in time also perfectly describe their evolution backwards in time. Why does the brain and the conscious experience that emerges from it, see the arrow of time so clearly? In other words why do we remember the past and not the future?

The Supernova At The End of Time

S7 E2 / 12m 12s

It looks like the universe is going to end with a series of catastrophic explosions. The very, very long story short is that the universe ends in heat death, as it approaches maximum entropy, and its eternal exponential expansion drives it to effective utter emptiness and absolute cold. But new calculations have revealed we may be able to look forward to one last source of astrophysical cataclysm

Navigating with Quantum Entanglement

S7 E3 / 12m 11s

Erwin Schrödinger suggests that “incredibly small groups of atoms, much too small to display exact statistical laws, do play a dominating role in the very orderly and lawful events within a living organism.” Schrodinger was a visionary - and perhaps very specifically in this case. Because it turns out we might need all the weirdness of quantum mechanics to explain birds.

What Happens During a Quantum Jump?

S7 E4 / 12m 43s

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.

Can We Break the Universe?

S7 E5 / 12m 32s

We 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.

Is Dark Matter Made of Particles?

S7 E6 / 13m 3s

By the time you've read this, a billion dark matter particles may have streamed through your body like ghosts. The particle or particles of the dark sector make up the vast majority of the mass of the universe - so to them, we're the ghostly ones. So, we try to make contact with dark matter particles and enter into the Dark Universe.

Gravitational Wave Background Discovered?

S7 E8 / 13m 54s

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.

Does Time Cause Gravity?

S7 E9 / 8m 55s

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 does gravity causes the flow of time to slow down? In a sense, it’s no. Gravity does NOT warp the flow of time. It’s the other way around the warping of time causes gravity.

How Does Gravity Affect Light?

S7 E10 / 13m 24s

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?

The New Crisis in Cosmology

S7 E11 / 13m 8s

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.

Zeno's Paradox & The Quantum Zeno Effect

S7 E12 / 12m 48s

A moving arrow is at rest.” Zeno, a Greek philosopher famous for his metaphysical trolling, devised a paradox whose conclusion is just this. If we’re talking about a quantum arrow, there may be a way to freeze its motion simply by looking at it, through the aptly named quantum Zeno effect. The Quantum Zeno effect predicts that certain quantum events can be frozen through this act of observation.

Why the Muon g-2 Results Are So Exciting!

S7 E13 / 12m 35s

What happens if a theory produces the most successful predictions in all of physics? Then, that little glitch may be pointing the way to layers of physics deeper than we've yet imagined. Well, FermiLabs Muon G-2 experiment has been chasing the most promising glitch of all, and they've just announced their results.

What If Dark Matter Is Just Black Holes?

S7 E14 / 12m 35s

It may be that for every star in the universe there are billions of microscopic black holes streaming through the solar system, the planet, even our bodies every second. Sounds horrible - but hey, at least we’d have explained dark matter.

The New Warp Drive Possibilities

S7 E15 / 13m 11s

Einstein's "nothing travels faster than light” rule seems to ensure that exploration of even the local part of our galaxy will be excruciatingly slow. But Einstein also gave us a glimmer of hope. He showed us that space and time can be warped - and so the warp drive was conceived.

How To Know If It's Aliens

S7 E16 / 14m 8s

There’s one rule on Space Time: It’s never Aliens. But every rule has an exception and this rule is no exception because: It’s never aliens, until it is. So is it aliens yet? And on today’s Space Time we’re going to examine all the best case scenarios for life beyond Earth.

Breaking The Heisenberg Uncertainty Principle

S7 E17 / 10m 48s

Quantum mechanics forbids us from measuring the universe beyond a certain level of precision. But that doesn’t stop us from trying. And in some cases succeeding, by squeezing the Heisenberg uncertainty principle to its breaking point.

What If Tiny Black Holes Are Everywhere?

S7 E18 / 11m 34s

Black holes may be the scariest objects in the universe. Luckily, the nearest is probably many light-years away. Unless of course, Planck relics are a thing - in which case they might be literally everywhere.

Are We Running Out of Space Above Earth?

S7 E19 / 13m 44s

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. 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.

How Quantum Entanglement Creates Entropy

S7 E21 / 14m 1s

Entropy is surely one of the most perplexing concepts in physics. It’s variously described as a measure of a system’s disorder - or as the amount of useful work that you can get from it - or as the information hidden by the system. Despite the seeming ambiguity in its definition, many physicists hold entropy to be behind one of the most fundamental laws of physics.

Supported by