Media reports say astronomers have discovered not one, not two, but seven Earth-sized planets orbiting a star called TRAPPIST-1.

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, according to Fox News.

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,” Michael Gillon, astronomer at the University of Liege in Belgium, added during the press conference.

This is the first time astronomers have found so many Earth-sized planets circling the same sun.

The three planets in the habitable zone, also known as the Goldilocks Zone, are called TRAPPIST-1e, f, and g. Exoplanet “e” is about the same size as Earth and even gets around the same amount of star light as we do.

Scientists already knew of thousands of planets beyond our own solar system.