After the big bang, all we had was hydrogen, a little bit of helium, and a few other trace elements. Today, we’ve a whole periodic table of elements to enjoy, from oxygen we breathe to the aluminium cans we drink from to the uranium that powers some people’s homes. How did we get from plain old hydrogen to our current diversity? It came from stars, in fact successive generations of stars.

Episode 75: Stellar Populations (14.4MB)

We’ve been so crazy following our own whims through the universe that we’ve neglected your questions. That ends today. It’s time to dig deep into our overflowing email box to retrieve the puzzling questions our listeners have sent in.

Episode 73: Questions Show #8 (16.8MB)

This week we're going to study some of the most ancient objects in the entire Universe; globular clusters. These relics of the early Universe contain hundreds of thousands of stars, held together by their mutual gravity. Since they formed together, they give astronomers a unique way to test various theories of stellar evolution.
Episode 68: Globular Clusters (14.3MB)

We've discussed star formation in the past, but now we wanted to talk about the different kinds of stellar nurseries we see across the Universe. We know where our Sun came from because we can look out and see different stellar neighborhoods at every stage of development. It takes a village of gas and dust to raise a star.

Episode 46: Stellar Nurseries (13.1MB)
 

Huge stars become black holes, and small stars become white dwarfs. But medium-sized stars can become neutron stars; exotic objects that overcome the nuclear force holding protons and electrons apart. What was once the size of a star is compressed down to only a few dozen kilometres across.

Episode 38: Neutron Stars and their Exotic Cousins(14.64MB)
 

Gamma ray bursts are the most powerful explosions in the Universe, releasing more energy in a few seconds than our Sun will put out in its lifetime. It's only been in the last few years that astronomers are finally starting to unravel the cataclysmic events that cause these energetic explosions.

Episode 36: Gamma-Ray Bursts (14MB)
 

It's Spring in the Northern Hemisphere, and that means the Sun is back. But it's more than just a free heat lamp for your garden, it's an incredible, dynamic nuclear reaction complete with flares, coronal mass ejections, twisting magnetic fields and the solar wind. Put in your headphones, head outside and enjoy the sunshine while you listen to this week's podcast.

Correction: At the beginning of the show I say the Sun has 50 billion years to go. I mentally combined two numbers. In 50 million years life will become untenable or impossible on Earth. In 5 billion years the sun goes off the main sequence. We are very sorry for the mistake. -Pamela

Episode 30: The Sun, Spots and All (14.4 MB)

Our Sun has been around for billions of years, and will last for billions more. We're lucky, it's pretty stable and regular as stars go, only changing in brightness a little now and then. But there are stars out there that change dramatically; astronomers call them variable stars, and they demonstrate just how bizarre and dangerous the Universe can be.

Episode 22: Variable Stars (28 MB)

No more suspense. This week we blow the biggest stars up. Kaboom. Want more details? Then you've got to listen.

Download Episode 14: We're all Made of Supernovae (12.3 MB)

We've celebrated the birth of new stars, but the stellar lifecycle doesn't end there. Stars like our Sun will spend billions of years fusing together hydrogen and pumping out energy. And when the fuel runs out, their death is as interesting as their birth. This week Fraser and Pamela trace out this stellar evolution, and explain what the future holds for stars, large and small.

Download Episode 13: Where Do Stars Go When They Die? (12.3 MB)