NASA's Spitzer Space Telescope has discovered a new solar system that could host alien life.

　　The system contains "seven rocky, Earth-sized planets," orbiting around a single star. Three of these planets lie firmly within the hospitable zone, and could therefore hold liquid water, a substance we believe to be essential for life.

　　The system, which lies around 40 light years (235 trillion miles) from Earth, has been named TRAPPIST-1, after a Chilean telescope that discovered three of the planets in 2016. That telescope is called The Transiting Planets and Planetesimals Small Telescope, hence "TRAPPIST."

　　"This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life," said Thomas Zurbuchen, associate administrator of the agency’s Science Mission Directorate in Washington. "Answering the question 'are we alone' is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal."

　　All seven of the planets lie closer to their star than the closest of our solar system's planets--Mercury--lies to the Sun. They may still be hospitable, however, since scientists believe TRAPPIST-1's star is cooler than our own.

　　We may find out more about the system in the future; in 2018, NASA will launch its new James Webb Telescope, which is capable of detecting the chemical properties of water, methane, and oxygen in potential atmospheres.

　　For now, you can read more about the discovery in the science journal Nature, or in NASA's press release.

　　If you want to discover new planets for yourself, you might be interested in Mass Effect: Andromeda, which launches on March 21 for PlayStation 4, Xbox One, and PC.