What a week! Astronomers announced the discovery of an Earth-sized planet orbiting the nearby star Gliese 581. We talk about the technique used to discover the planet, the possibilities of finding even smaller planets, and what the future holds for finding another Earth.

Correction: At the beginning of the show, Pamela says that Gliese 581c is estimated to have a mass of no more than 5.6 solar masses. The actual mass limit is estimated to be no more than 5.6 Earth masses. We are very sorry for the mistake. -Rebecca

Episode 34: Discovering Another Earth (13.6 MB)
 

We live in a mind bogglingly big Universe filled with countless stars. We know intelligent life evolved here on Earth. It must be common across the Universe, right? But if there's life out there, how come we haven't been visited by aliens yet? Why haven't we even picked up signals from alien television stations? Where's all the life?
 
 
Episode 24: Fermi Paradox (16.3 MB)

If you're wondering how many extraterrestrials there are in our galaxy, you just have to use a simple equation developed by astronomer Frank Drake in 1961. Just find out how many stars there are, how many support life, how many advanced societies form, and a few other details and we'll be set.

Episode 23: Drake Equation (18 MB)
 

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.

Download Episode 3: Hot Jupiters and Pulsar Planets (12.7 MB)

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.

Download Episode 2: In Search of Other Worlds (13.9 MB)