As Nasa scientists announce the discovery of a new solar system that has at least three Earth-like planets - is this newly discovered solar system proof we're not alone? br br br For centuries it has been one of the most vexing mysteries for mankind: are we, the seven billion inhabitants of this wondrous blue planet really alone, or is there life somewhere out there in the universe? br Yesterday, we came a step closer to answering that tantalising question with the landmark announcement by Nasa scientists of the discovery of a new solar system that has at least three Earth-like planets — with climates that just might support life. br The kind of planets that a certain ET might have called home. br The discovery by an international team using advanced telescopes in space and at far-flung locations around the world has caused a frenzy of excitement among astronomers who, as a breed, are not given to hyperbole.