Latifa Karama

Talk about lucky number seven. Astronomers have discovered not one, not two, but seven Earth-sized planets orbiting a star called TRAPPIST-1. What’s more, three of them are in the habitable zone— the happy place where liquid water can exist on the surface of rocky planets, as it’s not too hot or cold. (Although liquid water could potentially exist on any of the seven, NASA said, it likes the odds on those three best.) The space agency calls the discovery of the fascinating solar system record-breaking.  “The discovery gives us a hint that finding a second Earth is not just a matter of if, but when,” Thomas Zurbuchen, associate administrator of the Science Mission Directorate at NASA Headquarters, said at a news conference  announcing the discovery. Zurbuchen called it a "major step forward" towards the goal of answering the very big question: Is there life on other worlds? The discovery "is very promising for the search for life beyond our solar system,” Michae