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Astronomycast Episode 202 from Monday, October 11, 2010. The planet's a glaze of 581.

Welcome to Astronomycast, our weekly backspace journey through the cosmos, where we help you understand not only what we know, but how we know what we know.

My name is Fraser Kane, I'm the publisher of the universe today, and with me is Dr. Pamela Gay, a professor at Southern Illinois University, Everestville.

Hi Pamela, how are you doing?

I'm doing well, how are you doing Fraser?

Doing really well. So one thing that we wanted to let people know, just people running like, how can they help?

Just a reminder, anytime you want, you can go to iTunes and write a review for Astronomycast so that other people can see that people like this show, especially in other countries than the United States and the United Kingdom.

So if you're in Australia, or Ireland, or Canada, or New Zealand, South Africa, and even some of the countries that are not English as the main language, that would be a huge help.

So just go to iTunes, search for Astronomycast, and then write a review, and that can help other people find out about our show. So if you can do that, that would be awesome.

Okay, so with the discovery of a planet in the habitability zone of Glyza 581, the chances of finding life on other worlds is just getting better and better.

Let's take a look at the discoveries made at Glyza 581 and provide some perspective on the real chances of life and talk about what might come next.

Well, Pamela, let's first talk about just the system itself and the discoveries that have gone on so far leading up to the momentous announcement in the last few weeks, if you could.

Well, this is a star that has been studied for a long time, for a lot of fairly straightforward reasons. First of all, it's fairly close.

This is the 87th closest known star system to the sun. So that means that even though it's 20.3 light years away, as faint as it is, we can get very accurate measurements of what this little star is doing.

So people start studying it, looking at its radial velocities. How does it move to and fro along our line of sight? Hopefully because it's getting yanked about by little worlds.

And as early as 2007, these radial velocity curves, these measurements of its Doppler shifting, began to reveal that there was something pretty interesting going on in the system.

In April of 2007, it was announced by Udry at all. It's not a star. There's a planet that's probably only one and a half times the radius of the earth that's orbiting this one third the size of the sun star.

So that was the first planet discovered around the star. That was the very first planet. But this was just the beginning.

It was. And the more they looked at this little planet, the more and more little worlds began to crop up, not actually that little. They'd be pretty big if they were in our own solar system.

So as continued to look, new press releases slowly came out one by one, indicating first a second planet, then a third planet, then a fourth planet.

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