Horizon: Are we Alone in the Universe?

For fifty years, the Search for Extra Terrestrial Intelligence (SETA) has been scanning the galaxy for a message from an alien civilisation. So far to no avail, but a recent breakthrough suggests they may one day succeed. Horizon joins the planet hunters who have discovered a new world called Gliese 581c, which may have habitats capable of supporting life. NASA hopes to find fifty more Earth-like planets by the end of the decade, all of which dramatically increases the chance that alien life has begun elsewhere in the galaxy.