A few of the worlds might even be habitable.
The monumental discovery has prompted scientists to launch a website for the planetary system - and yes, it has an equally monumental domain: trappist.one.
Researchers inspired by the new planetary system, which is about 39 light-years from Earth, are using trappist.one to publish fiction, artwork, and even poetic prose about it.
One poem by Sean Raymond, an astronomer at the Laboratoire d'Astrophysique de Bordeaux who co-authored a study in Nature about the planetary system, caught our eye.
Called "Ode to 7 orbs", it beautifully explains the discovery and importance of TRAPPIST-1's seven planets.
Raymond gave Business Insider permission to share his work, which we've reproduced here with a few illustrative additions.