Ep. 140: Entanglement

Artist's impression of an experiment to test entanglement

One of the most amazing aspects of quantum mechanics is quantum entanglement. This is the strange behavior where particles can become entangled, so they're somehow connected to one another – no matter the distance between them. Interact with one particle and the other reacts instantly; even if they're separated by billions of light-years.

Ep. 140: Entanglement
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Ep. 139: Energy Levels and Spectra

Stellar Spectra. Image credit: NOAO

Last week we took a peek into the tiny world of quantum mechanics, and its unintuitive, but very accurate mathematical predictions. And although we all appreciate the physics lesson, you're probably wondering what this all has to do with astronomy. Well, today we bring it all home and explain how quantum mechanics has given astronomers one of the most powerful tools they have to study the nature of the cosmos.

Ep. 139: Energy Levels and Spectra
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Ep. 138: Quantum Mechanics

Einstein, one of the founders of quantum mechanics

Quantum mechanics is the study of the very tiny; the nature of reality at the smallest scale. It's a science that defies common sense, and delivers no helpful analogies. And yet it delivers the goods, making scientific predictions with incredible accuracy. Let's look into the history of quantum theory, and then struggle to comprehend its connection to the Universe.

Ep. 138: Quantum Mechanics

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Ep. 117: Time

Ancient Chinese sundial and observatory.

Today, time rules our lives. We live each day with the moments broken up into hours, minutes and seconds. We never seem to have enough time. But can you imagine not being able to tell time at all, where the movements of the Sun and the stars was the only way to know what time it was? Let's learn about the history of time, methods of telling time, and Einstein's historic discovery that time isn't as fixed as we thought it was.

Ep. 117: Time
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Questions Show – light speed, Andromeda galaxy, dark matter and black holes

Another week, another roundup of your questions. This week listeners asked: will reaching light speed destroy the Universe? When is Andromeda going to look really, really cool with the unaided eye? Why didn't dark matter all turn into black holes? And there's even more. If you've got a question for the Astronomy Cast team, please email it in to info@astronomycast.com and we'll try to tackle it for a future show.

Show – light speed, Andromeda galaxy, dark matter and black holes (17.07MB)
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Ep. 107: Nucleosynthesis: Elements from Stars

Look around you. Breathe in some air. Everything you can see and feel was formed in a star. Today we'll examine that long journey that matter has gone through, forged and re-forged in the hearts of stars. In fact, the device you're using to listen to this podcast has some elements formed in a supernova explosion.

Ep. 107: Nucleosynthesis: Elements from Stars
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Ep. 106: The Search for the Theory of Everything

At the earliest moments of the Universe, there were no separate forces, energy or matter. It was all just the same stuff. And then the different forces froze out, differentiating into electromagnetism, the strong force and the weak force. Today we'll look at the problem that has puzzled physicists for generations: is there a single equation that explains all the forces we see in the Universe. Is there a theory of everything?

Ep. 106: The Search for the Theory of Everything
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Ep. 105: The Strong and Weak Nuclear Forces

After a quick Dragon*Con break, we're back to our tour through the fundamental forces of the Universe. We've covered gravity and electromagnetism, and now we're moving onto the strong and weak nuclear forces. We didn't think they'd really need to be separate episodes, so we're putting them together. And then we'll cap the whole series with the quest for the theory of everything.

Ep. 105: The Strong and Weak Nuclear Forces
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Ep 102: Gravity

You seem to like a nice series, so here's a new one we've been thinking about. Over the course of the next 4 weeks, we're going to cover each of the basic forces in the Universe. And this week, we're going to start with gravity; the force you're most familiar with. Gravity happens when masses attract one another, and we can calculate its effect with exquisite precision. But you might be surprised to know that scientists have no idea why gravity happens.

Ep. 102: Gravity
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Ep. 96: Humans to Mars, Part 3 – Terraforming Mars

And now we reach the third part of our trilogy on the human exploration and colonization of Mars. Humans will inevitably tire of living underground, and will want to stretch their legs, and fill their lungs with fresh air. One day, we'll contemplate the possibility of reshaping Mars to suit human life. Is it even possible? What technologies would be used, and what's the best we can hope for?

Ep. 96: Humans to Mars, Part 3 – Terraforming Mars
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