Has the likelihood of alien life existing just become a lot more likely? Astronomers at the Harvard-Smithsonian Centre for Astrophysics announced this week that they have found what's being dubbed the "Godzilla of Earths" - it's a rocky planet orbiting a distant star over 500 light years away. But it's over twice the diameter and 17 times the mass of the Earth. So it's exciting for two reasons - first, space scientists had thought that planets could only be that big if they were made of gas, like Neptune or Jupiter, rather than rock, like Earth; and, second, the star this planet is orbiting is over 10 billion years old, proving that rocky planets, that could harbour life, have been around for much longer than we have. To find out more about the implications, Chris Smith went to see Cambridge University's own alien planet hunter, Madhu Madhusudhan.