How did NASA find solar system with 7 Earth-like planets?
The discovery of a new solar system containing seven Earth-like planets was majorly made by NASA's Spitzer Space Telescope and ground-based TRAPPIST telescope. The telescopes measured the star's brightness over time. When the planets passed in front of the star, its brightness slightly fainted. The duration and depth of these changes in brightness were studied to identify the seven exoplanets.