549: Stellar nucleosynthesis revisited: In and on and around dead stars Astronomy Cast 549: Stellar nucleosynthesis revisited: In and on and around dead stars by Fraser Cain & Dr. Pamela Gay Last week we gave you an update on the formation of elements from the Big Bang and in main sequence stars like the Sun. This week, we wrap up with a bang, talking about the death of the most massive stars and how they seed the Universe with heavier elements.

548: Stellar nucleosynthesis revisited: In stellar cores & atmospheres Astronomy Cast 548: Stellar nucleosynthesis revisited: In stellar cores & atmospheres by Fraser Cain & Dr. Pamela Gay The Universe started out with hydrogen and helium and a few other elements, but all around us, there are other, more proton-rich elements. We believe these heavier elements formed in stars, but which stars? And at what points in their lives? Today we'll update our knowledge with the latest science.

547: Why Astronomy Still Needs Humans Astronomy Cast 547: Why Astronomy Still Needs Humans by Fraser Cain & Dr. Pamela Gay Few sciences have been able to take advantage of the power of computers like astronomy. But with all this computing power, you might be surprised to learn how important a role humans still play in this science.

546: Weird Issues: Planetary Migration Astronomy Cast 546: Weird Issues: Planetary Migration by Fraser Cain & Dr. Pamela Gay Before we discovered other planets, our Solar System seemed like a perfectly reasonable template for everywhere. But now we see massive planets close to their stars, which leads you to the question, how does it all get there. Do the planets form in place or do they migrate around?

545: Weird Issues: Are comets asteroids or are asteroids comets? Astronomy Cast 545: Weird Issues: Are comets asteroids or are asteroids comets? by Fraser Cain & Dr. Pamela Gay Things used to be so simple. Comets were snowballs from the outer Solar System, and asteroids were rocks from the inner Solar System. But now everything's all shades of grey. Astronomers have found asteroids that behave like comets and comets that behave like asteroids.

544: Weird Issues: Biosignatures Astronomy Cast 544: Weird Issues: Biosignatures by Fraser Cain & Dr. Pamela Gay Once again, another place where the Universe is going to make this difficult for us. Proving, once and for all that there's alien life on another world. It should be straightforward, look for biosignatures, but it looks like there are natural sources that could explain almost any chemical we could hope to search for.

Got clear skies? Go out tonight and catch the Orionids Meteor shower, a storm of falling stars generated by Halley's comet. Later this week, we'll see aurora like those that will one day be predicted by the ESA Solar Probe. We also have an update on the Mars 2020 rover.

543: Weird Issues: The Habitable Zone Astronomy Cast 543: Weird Issues: The Habitable Zone by Fraser Cain & Dr. Pamela Gay Our series on Universe weirdness marches on. This week we take a look at the habitable zone, and how things aren’t as simple as we thought.

542: Weird Issues: The Age of the Universe Astronomy Cast 542: Weird Issues: The Age of the Universe by Fraser Cain & Dr. Pamela Gay Our series on Universe weirdness continues, this time we learn how astronomers are struggling to make sense of the age of the Universe.

541: Weird Issues: Expansion Rate of the Universe Astronomy Cast 541: Weird Issues: Expansion Rate of the Universe by Fraser Cain & Dr. Pamela Gay Just when the Universe was starting to make sense, the cosmos throws a curveball at us. Astronomers have been trying to accurately measure the expansion rate of the Universe as far back as Hubble. It's been tough to nail down, and now astronomers are starting to figure out why.