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12m 33s

Is Time Travel Impossible?

Time travel stories are cool because both the past and future are somehow more interesting that the present and because everyone wants a redo. But so far it appears we’re doomed to live consumed by regret in the eternal, boring present. Time marches on, inexorably and only forward. Or so we thought until Einstein came along.

11m 20s

How Black Holes Kill Galaxies

When we first realized that black holes could have masses of millions or even billions of times that of the sun, it came as a bit of a shock. They were discovered as the driving force behind quasars, where matter is heated to extreme incandescence before its plunge into vast black holes. But if that weren’t enough, we soon realized that every decent-sized galaxy contains a supermassive black hole.

10m 37s

No Dark Matter = Proof of Dark Matter?

We’ve been failing to detect dark matter for decades. Finally, the latest failure to detect dark matter may have actually proved its existence. One of these is true: either most of the matter in the universe is invisible and formed of something not explained by modern particle physics OR our understanding of gravity is completely broken.

14m 39s

The Holographic Universe Explained

We live in a universe with 3 dimensions of space and one of time. Up, down, left, right, forward, back, past, future. 3+1 dimensions. Or so our primitive Pleistocene-evolved brains find it useful to believe. And we cling to this intuition, even as physics shows us that this view of reality may be only a very narrow perception.

15m 16s

The Edge of an Infinite Universe

Have you ever asked “what is beyond the edge of the universe?” And have you ever been told that an infinite universe that has no edge? You were told wrong. In a sense. We can define a boundary to an infinite universe, at least mathematically. And it turns out that boundary may be as real or even more real than the universe it contains.

14m 31s

Is Dark Energy Getting Stronger?

The power of Dark Energy may be increasing as the universe ages. Subtle clues are emerging that the accepted model for the nature of dark energy and dark matter may not be all that. We saw the first such clue recently in our recent episode on the Crisis in Cosmology. Today we’re doing a Space Time Journal Club to reveal another clue

12m 46s

Will You Travel to Space?

The private space-race has been on for a while now. The attention has been on Space-X and Blue Origin with their reusable rockets. But there’s one private space program that’s been doing things a little differently. Richard Branson’s Virgin Galactic isn’t building rockets at all – it’s building spaceships. And I got to sit down and talk to him about it.

11m 7s

The Real Science of the EHT Black Hole

How do you take a picture of a black hole and what can we learn from it? Our first ever actual bona fide photo of a black hole, made by the Event Horizon Telescope and revealed to the world in a press conference on April 10th. Since then it’s got plenty of coverage, because … I mean look at it. It’s a freaking black hole. It’s black, it’s holey, it’s everything we hoped it would be.

13m 53s

Secrets of the Cosmic Microwave Background

Hook up an old antenna to your TV and scan between channels. The static buzz you hear is mostly due to the ambient radio produced by our noisy pre-galactic civilization. But around one percent of that buzz is something very different – it’s the cosmic microwave background radiation.

12m 48s

Sound Waves from the Beginning of Time

Invisible to the naked eye, our night sky is scattered with the 100s of billions of galaxies the fill the known universe. Like the stars, these galaxies form constellations – hidden patterns that echo the reverberations of matter and light in an epoch long before galaxies ever formed. These are the baryon acoustic oscillations, and they may hold the key to understanding the nature of dark energy.

14m 28s

Perpetual Motion From Negative Mass?

Challenge question: if 1kg of apples is $5 and 2kg is $10, how much is -1kg of apples? The answer? Priceless. Because you could use negative-mass apples to build warp drives, travel in time, and construct a perpetual motion machine. In fact that last one will be today’s actual challenge question.

13m 17s

The Crisis in Cosmology

The search for a single number: the hubble constant, which is the rate of expansion of our universe, has consumed astronomers for generations. Finally, two powerful and independent methods have refined its measurement to unprecedented precision. The only problem is that they don’t agree. This calls into question some of our most basic assumptions about the universe.

13m 50s

Our Antimatter, Mirrored, Time-Reversed Universe

The foundations of quantum theory rests on its symmetries. For example, it should be impossible to distinguish our universe from one that is that is the perfect mirror opposite in charge, handedness, and the direction of time. But one by one these symmetries were found to be broken, threatening to break all of physics along with them.

15m 7s

Why String Theory is Wrong

There’s this idea that beauty is a powerful guide to truth in the mathematics of physical theory. String theory is certainly beautiful in the eyes of many physicists. Beautiful enough to pursue even if it’s wrong?

13m 8s

Are Dark Matter And Dark Energy The Same?

Astronomers are the worst at naming things. Dark energy AND dark matter? Who can remember which is which. But perhaps one astronomer has just fixed it, with a theory that says perhaps actually they are they same stuff.

14m 21s

Did Life on Earth Come from Space?

How did life on Earth get started? Did life on Earth originate on another planet? Either Mars, or in a distant solar system? Could Earth life have spread to have seeded life elsewhere? Let’s see what modern science has to say about the plausibility of panspermia.

13m 4s

'Oumuamua Is Not Aliens

To repeat the space time maxim: it’s never aliens … until it is. So let’s talk about ‘oumuamua.

13m 37s

Why String Theory is Right

Some see string theory as the one great hope for a theory of everything – that it will unite quantum mechanics and gravity and so unify all of physics into one glorious theory.

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