Astronomy Cast

You hear distances all the time in astronomy. This star is 10 light-years away; that galaxy is 50 million light-years away; that Big Bang over there happened 13.7 billion years ago. But how did astronomers actually figure out how far away everything is? It's not a single measuring stick. Instead, astronomers have built up a series of overlapping measuring tools (yes, we're calling supernovae and variable stars tools), which take us from right around the corner to very ends of the Universe. Get out your ruler... no, the bigger one... never mind... just listen.

It's all relative. How many times have you heard that? Well, when you're traveling close to the speed of light, everything really is relative; especially the passage of time. This week, Fraser and Pamela give you the skinny on Einstein's Special Theory of Relativity. After listening to a few thought experiments, you too should be able to wrap your head around this amazing theory.

Dress warmly, gather some friends and family, and head outside to watch sand burn in the upper atmosphere. There's nothing like a good meteor shower. Fraser and Pamela explain this beautiful phenomenon: what causes them, the best storms and showers to watch for, and different types of meteors you might see.

Got your eye on that $40 telescope at Walmart? Wait, hear us out first! Fraser and Pamela discuss strategies for getting into amateur astronomy - one of the most worthwhile hobbies out there. We discuss what gear to get, where to look, and how to meet up with other astronomy enthusiasts.

Last week's episode started out with a bang- a Big Bang. This week we continue our discussion into the beginning of everything. We present three additional lines of evidence that have led astronomers to the conclusion that our Universe started out as a singularity 13.7 billion years ago, and has been expanding ever since.

As a tribute to John Mather and George Smoot, the two leaders of the Cosmic Microwave Background Explorer (COBE) satellite science team, and winners of this year's Nobel Prize for Physics, we head back to the beginning of everything- the Big Bang. Follow as we trace the Big Bang's discovery, and one of the most important lines of evidence: the cosmic microwave background radiation which was predicted by theory and then discovered by accident.

Dark matter . . . What is it? Nobody knows for sure, but it's definitely there. Or maybe it's not there, and we just need some redefinition of gravity at vast scales. Join Fraser and Pamela as we discuss the discovery, detection, and possible explanations of dark matter.

You have lived on the Earth all your life, so you'd think you know plenty about planets. As usual though, the Universe is stranger than we assume, and the planets orbiting other stars defy our expectations. Gigantic super-Jupiters whirling around their parent stars every couple of days; fluffy planets with the density of cork; and Earth-sized fragments of exploded stars circling pulsars. Join us as we round up the latest batch of bizarro worlds.

Look down at your feet. There... you're looking at a planet. Now look into the night sky and you should be able to spot a few more. After that, spotting additional planets becomes really hard, especially when you're trying to find them orbiting other stars. This week we discuss the techniques astronomers use to locate distant worlds.

Pluto. It's a planet, then it's not. This week we review Pluto's history, from discovery to demotion by the International Astronomical Union. Learn the 3 characteristics that make up a planet, and why Pluto now fails to make the grade.