NASA's Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star.
Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water.
Assisted by several ground-based telescopes, including the European Southern Observatory's Very Large Telescope, Spitzer confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.
In contrast to our sun, the TRAPPIST-1 star classified as an ultra-cool dwarf is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar
Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water.
Assisted by several ground-based telescopes, including the European Southern Observatory's Very Large Telescope, Spitzer confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.
In contrast to our sun, the TRAPPIST-1 star classified as an ultra-cool dwarf is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar